Ve ?

[Taylorman]

So a NA unless very tricked out does not reach 100% VE right? Blowers are used to get the motor to 100 and above 100% VE right. How much boost is required just to get the motor to 100%? The more boost the hight the VE right?

[steelcomp]

So a NA unless very tricked out does not reach 100% VE right? Blowers are used to get the motor to 100 and above 100% VE right. How much boost is required just to get the motor to 100%? The more boost the hight the VE right?Plenty of NA motors running past 100%VE.
Your question needs a lot more info to be answered. Each motor is diferent and will have different requirements.

[TurboNova]

Let's look at what VE actually is.
"The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE). An engine operating at 100% VE is ingesting its' total displacement every two crankshaft revolutions.
Volumetric Efficiency, For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages and valve system components.
Generally, the RPM at peak VE coincides with the RPM at the torque peak. And generally, automotive engines rarely exceed 90% VE. There is a variety of good reasons for that performance, including the design requirements for automotive engines (good low-end torque, good throttle response, high mileage, low emissions, low noise, inexpensive production costs, restrictive form factors, etc.), as well as the allowable tolerances for components in high-volume production.
For a known engine displacement and RPM, you can calculate the engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm) as follows:
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456"
This equation is theoretical VE and not the actual VE of the engine.
I have tuned quite a few turbo engines in the 95% efficiency, but have yet to even see an engine that makes 100% and I don't think over 100% is truly achievable. Even when you have a boosted engine it will not make your VE higher it will just make the air charge more dense, the engine can only still pump out a maximum volume of air. Most of the engines I see even the boosted ones are in the 80%-90% range.

[Morg]

Let's look at what VE actually is.
"The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE). An engine operating at 100% VE is ingesting its' total displacement every two crankshaft revolutions.
Volumetric Efficiency, For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages and valve system components.
Generally, the RPM at peak VE coincides with the RPM at the torque peak. And generally, automotive engines rarely exceed 90% VE. There is a variety of good reasons for that performance, including the design requirements for automotive engines (good low-end torque, good throttle response, high mileage, low emissions, low noise, inexpensive production costs, restrictive form factors, etc.), as well as the allowable tolerances for components in high-volume production.
For a known engine displacement and RPM, you can calculate the engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm) as follows:
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456"
This equation is theoretical VE and not the actual VE of the engine.
I have tuned quite a few turbo engines in the 95% efficiency, but have yet to even see an engine that makes 100% and I don't think over 100% is truly achievable. Even when you have a boosted engine it will not make your VE higher it will just make the air charge more dense, the engine can only still pump out a maximum volume of air. Most of the engines I see even the boosted ones are in the 80%-90% range.
Excellent post,
The problem is, reality sucks. And motor builders have goals promissed to customers.
This may get interesting. :) :)

[steelcomp]

Let's look at what VE actually is.
"The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE). An engine operating at 100% VE is ingesting its' total displacement every two crankshaft revolutions.
Volumetric Efficiency, For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages and valve system components.
Generally, the RPM at peak VE coincides with the RPM at the torque peak. And generally, automotive engines rarely exceed 90% VE. There is a variety of good reasons for that performance, including the design requirements for automotive engines (good low-end torque, good throttle response, high mileage, low emissions, low noise, inexpensive production costs, restrictive form factors, etc.), as well as the allowable tolerances for components in high-volume production.
For a known engine displacement and RPM, you can calculate the engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm) as follows:
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456"
This equation is theoretical VE and not the actual VE of the engine.
I have tuned quite a few turbo engines in the 95% efficiency, but have yet to even see an engine that makes 100% and I don't think over 100% is truly achievable. Even when you have a boosted engine it will not make your VE higher it will just make the air charge more dense, the engine can only still pump out a maximum volume of air. Most of the engines I see even the boosted ones are in the 80%-90% range.
How many examples of an NA engine exceeding 100% VE would you like?

[92562]

How many examples of an NA engine exceeding 100% VE would you like?I wouldn't mind seeing one. :D
Since an engine is nothing more than an air pump, just looking at the VE equation tells me that due to little things like blow-by, etc. you'll never reach theoretical VE. Maybe a good rotary? Unless I am oversimplifying things, teach me something here.

[steelcomp]

For starters, Here's a single four barrel 427" SB Chev.ETAVBWIN.ZIP
looks like you are "Trapping" at least 117.0 VE % or more
without wasting too much out of exhaust or rings
CID= 427.445 --- Fuel Consumed in Lbs/Hour ---
CFM @ 12.5:1 13.2:1 14.0:1 14.7:1 16.0:1 Fuel Engine
Engine 117.0 A/F A/F A/F A/F A/F Heat Friction
RPM Ve % Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr HP HP
5700 824.8 258.2 244.5 230.5 219.6 201.7 1835 129.3
5800 839.3 262.7 248.8 234.6 223.4 205.3 1867 134.3
5900 853.8 267.3 253.1 238.6 227.3 208.8 1899 139.5
6000 868.2 271.8 257.4 242.7 231.1 212.3 1931 144.7
6100 882.7 276.3 261.7 246.7 235.0 215.9 1964 150.0
6200 897.2 280.8 266.0 250.8 238.8 219.4 1996 155.4
6300 911.7 285.4 270.2 254.8 242.7 222.9 2028 161.9
6400 926.1 289.9 274.5 258.8 246.5 226.5 2060 168.5
6500 940.6 294.4 278.8 262.9 250.4 230.0 2092 175.2
6600 955.1 299.0 283.1 266.9 254.2 233.6 2125 182.1
6700 969.5 303.5 287.4 271.0 258.1 237.1 2157 189.1
6800 984.0 308.0 291.7 275.0 261.9 240.6 2189 196.2
6900 998.5 312.6 296.0 279.1 265.8 244.2 2221 203.5
7000 1013.0 317.1 300.3 283.1 269.6 247.7 2253 210.9
7100 1027.4 321.6 304.6 287.2 273.5 251.3 2286 218.8
7200 1041.9 326.1 308.8 291.2 277.3 254.8 2318 226.8
7300 1056.4 330.7 313.1 295.2 281.2 258.3 2350 235.0
7400 1070.8 335.2 317.4 299.3 285.0 261.9 2382 243.2
7500 1085.3 339.7 321.7 303.3 288.9 265.4 2414 251.7
7600 1099.8 344.3 326.0 307.4 292.7 269.0 2447 260.2
7700 1114.3 348.8 330.3 311.4 296.6 272.5 2479 268.9
CID= 427.445 --- Fuel Consumed in Lbs/Hour ---
CFM @ 12.5:1 13.2:1 14.0:1 14.7:1 16.0:1 Fuel Engine
Engine 117.0 A/F A/F A/F A/F A/F Heat Friction
RPM Ve % Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr HP HP
7800 1128.7 353.3 334.6 315.5 300.4 276.0 2511 278.0
7900 1143.2 357.8 338.9 319.5 304.3 279.6 2543 287.3
8000 1157.7 362.4 343.2 323.6 308.1 283.1 2575 296.9
8100 1172.1 366.9 347.5 327.6 312.0 286.6 2607 306.5
8200 1186.6 371.4 351.7 331.6 315.8 290.2 2640 316.4
8300 1201.1 376.0 356.0 335.7 319.7 293.7 2672 326.3
8400 1215.5 380.5 360.3 339.7 323.6 297.3 2704 336.4
8500 1230.0 385.0 364.6 343.8 327.4 300.8 2736 346.7
8600 1244.5 389.6 368.9 347.8 331.3 304.3 2768 357.5
8700 1259.0 394.1 373.2 351.9 335.1 307.9 2801 368.5
8800 1273.4 398.6 377.5 355.9 339.0 311.4 2833 379.7
8900 1287.9 403.1 381.8 360.0 342.8 315.0 2865 391.0
9000 1302.4 407.7 386.1 364.0 346.7 318.5 2897 402.5
9100 1316.8 412.2 390.3 368.0 350.5 322.0 2929 414.2
9200 1331.3 416.7 394.6 372.1 354.4 325.6 2962 426.0
9300 1345.8 421.3 398.9 376.1 358.2 329.1 2994 437.9
9400 1360.3 425.8 403.2 380.2 362.1 332.7 3026 450.1
9500 1374.7 430.3 407.5 384.2 365.9 336.2 3058 462.3
9600 1389.2 434.9 411.8 388.3 369.8 339.7 3090 474.8
9700 1403.7 439.4 416.1 392.3 373.6 343.3 3123 487.4
Note=> Air/Fuel Ratio will shift towards 12.5:1 to 13.2:1
for non-acceleration Steady-State type Dyno test.
Air/Fuel Ratio will shift towards 14.0:1 to 14.7:1
for 600 RPM/SEC or faster acceleration type Dyno test
Fuel in Lbs./Hour at various Air/Fuel Ratios may differ from
actual Dyno Data due to Fuel Specific Gravity and Temperature
Fuel Heat HP = the amount of Energy per Lbs. of Fuel converted into HP
Friction HP = the amount of mechanical and fluid friction losses,
along with Pumping Losses ... based upon research
by GM , Honda , SuperFlow equations , and others.
at 300 RPM/SEC its =>
427.445 Cubic Inches @ 8200 RPM with 117.0 % Volumetric Efficiency PerCent
Required Intake Flow between 396.1 CFM and 420.6 CFM at 28 Inches
Required Exhaust Flow between 244.9 CFM and 284.9 CFM at 28 Inches
300 RPM/Sec Dyno Test Low Normal Best
Peak HorsePower 965.1 980.1 995.1
Peak Torque Lbs-Ft 667.2 674.1 681.0
HorsePower per CID 2.258 2.293 2.328
Torque per Cubic Inch 1.561 1.577 1.593
BMEP in psi 235.4 237.8 240.2
Carb CFM at 1.5 in Hg. 1187 1320 1454
Target EGT= 1118 degrees F during 4 second 600 RPM/Sec Dyno accel. test
Octane (R+M)/2 Method = 115.1 to 115.0 Octane required range
_________________

[steelcomp]

I wouldn't mind seeing one. :D
Since an engine is nothing more than an air pump, just looking at the VE equation tells me that due to little things like blow-by, etc. you'll never reach theoretical VE. Maybe a good rotary? Unless I am oversimplifying things, teach me something here.
A quick look at an engine as an air pump in a static state may give you that impression, but under dynamic conditions, things aren't as they seem. Optimizing airflow into, and out of an engine, and the combustion process that takes place during that period, has become very sophisticated...to a level that is difficult to understand without a physics and engineering degree.
Trust me...100%VE is commonplace.

[92562]

Thanks,
I have the physics degree, but it's geared toward nuclear medicine, not engineering! It just seemed to me that the only way to get more out than you put in is to consider that the heated gases take up more volume than the cool intake gases. I've only dynoed a handful of the engines I've built and frankly, never paid that column much attention. Thanks for the education! :cool:

[steelcomp]

Thanks,
I have the physics degree, but it's geared toward nuclear medicine, not engineering! It just seemed to me that the only way to get more out than you put in is to consider that the heated gases take up more volume than the cool intake gases. I've only dynoed a handful of the engines I've built and frankly, never paid that column much attention. Thanks for the education! :cool:
Air can be compressed. A moving column of air can be accelerated, then suddenly stopped in the front, yet continue to move in the rear, packing the molecules together, and compressing. Then, at the proper moment, the door is shut from behind, trapping that compreessed column of air. This is called ram effect, and in an oversimplified manner, can "overfill" a given volume. Port shapes, intake runners, exhaust, cam timing can all effect this ram effect to the point of exceeding the calculated volume of an engine at a given rpm.
Volumetric effeciency isn't letting out more than you take in, rather, it's the ability of the engine to take in near, or above it's calculated volume. What goes out is another story all together.

[TIMINATOR]

Steel and me agree on somthing? OMFG!!!!!! Look at any NASCAR,sprint car,decent drag or boat motor and VE is over 100%. This started to become more commonplace in the early 60s when intake ram tuning became more common. Tuned exhaust, better heads (cnc'd), roller cams, and more precision machining make this fairly easy actually. TIMINATOR

[cstraub]

100% VE is possible in an NA engine. The last few dyno sheets I have gotten on 540 CID engines they were 101 to 102%. As Steel and Timm pointed out RAM effect has alot to do with it. As steel stated this is the column of air that is entering the cylinder. . .this column has 2 things mass and velocity. What happens is after the intake valves starts to close and the pistons reaches BDC and begins to travel up on the compression stroke this column of air is still filling the cylinder. This added air and fuel packs the cylinder with "more" air then it takes to fill it.
Stroke helps in the ram effect especially at lower rpm ranges say around 3000. Piston speed is increased so as the piston travels down on the intake stroke there is more draw on the intake track. This builds more air velocity and will allow the RAM effect to be more prevelant.
As Timm pointed out the Cup engines run around 115% to 117% VE. I am told that top NHRA Pro Stock engines are about the same if not a little higher then the Cup stuff. These NA engines are the cream of the crop.

[Morg]

I've been reading this post for the pat couple of days. I have never studied a dyno sheet. Never really thought they were usefull for what I am doing. I will never be able to duplicate what a dyno will tell me. Why spend the money? the only thing I would do with the results would be show my buddies, & they would just say BFD, I still run faster than you....
But are you telling me that a 427ci sbc normaly aspirated with a single 4 barrel made 995.1 HP & 681.0 lbs or torque?
"300 RPM/Sec Dyno Test Low Normal Best
Peak HorsePower 965.1 980.1 995.1
Peak Torque Lbs-Ft 667.2 674.1 681.0"
You guys have mentioned Pro-stock & cup cars. I would consider those deals having un-limited budgets & the best head builders out there. I would say that they can make that happen.
Which is all fine & good. But is anybody in here able to lay down over $8000 for a a pair of heads?
I still say reallity sucks & motor builders need to justify the costs with a dyno sheet that shows what they said they would produce.

[steelcomp]

Morg, there is way more info on a dyno than just power numbers, but bottom line is, no one races dynos. An engine that accelerates a given load fastest from point A to point B wins, regardless of horsepower. (quote: Larry Widmer) This is why I started the thread a while back about "what makes an engine accelerate". The best accelerating engines don't always make the most HP. Dyno's can show trends, and curves. Without a dyno, you really have no way of knowing how your engine is going to perform untill it's too late, and you find you missed the power band by 1K rpm, and get left behind out of the corners. :cry:
But are you telling me that a 427ci sbc normaly aspirated with a single 4 barrel made 995.1 HP & 681.0 lbs or torque?Ten-four.
Here are some quotes from another site where I posted a question asking guys to give examples of their engines with VE exceeding 100%:
"personally i've never had an engine under 100%. i don't think your pal has much to dispute. the best v/e engine i've done is a s.b. mopar 461 cube single four barrel 94 octane pump gas deal that was solid in the 120's & tickled 127%. all of my really good engine's are in the low 120's, somewhere in the 1-teen's is nothing to sneeze though i am curious as to what the pro-stocker's are at these day's, or even if it's a number they pay any kind of attention to. good or bad it's a number i watch."
"My 502 was around 104VE from what I remember, its been a few yrs.
What do you guys think, a wimpy street motor makin over 100 doesnt seem that hard?"
"I did a LS1 408 stroker with a mild cam that had 105%, and that was on the dyno. Might have the datalog of the run if you're interested."
"I had my 434 sbc dynoed, it is NA, and was 113-115 for most of the pull with a high of 120 at one point. You can look at the dyno sheet and specs here" http://www.knights-rule.com/cgi/gallery/v/members/70mc/

[steelcomp]

100% VE is possible in an NA engine. The last few dyno sheets I have gotten on 540 CID engines they were 101 to 102%. As Steel and Timm pointed out RAM effect has alot to do with it. As steel stated this is the column of air that is entering the cylinder. . .this column has 2 things mass and velocity. What happens is after the intake valves starts to close and the pistons reaches BDC and begins to travel up on the compression stroke this column of air is still filling the cylinder. This added air and fuel packs the cylinder with "more" air then it takes to fill it.
Stroke helps in the ram effect especially at lower rpm ranges say around 3000. Piston speed is increased so as the piston travels down on the intake stroke there is more draw on the intake track. This builds more air velocity and will allow the RAM effect to be more prevelant.
As Timm pointed out the Cup engines run around 115% to 117% VE. I am told that top NHRA Pro Stock engines are about the same if not a little higher then the Cup stuff. These NA engines are the cream of the crop.
Hey, wow! Chris...where you been?
Coming up for a little air? :D
Nice to hear from you.

[cstraub]

Hey, wow! Chris...where you been?
Coming up for a little air? :D
Nice to hear from you.
It is busy. I've browsed the forums but have not posted much. How's that last project coming along?

[Morg]

Ok,
I will agree that a dyno will tell you where you are making the power & where to set your deal up. That is basic.
And like you said you don't race dyno's.
Tell me this, The dyno is calculating how much power you are making & also telling you what the VE numbers are. Would'nt the calibration of the dyno be determining these numbers?
Is the operator setting the calibration??
Are you ever going to see those conditions in the real world???

[78Eliminator]

Morg, you got it all wrong. Dynos are what it's all about, baby. Dyno sheets and how big of a tachometer you can fit on your dash.

[Morg]

Dude, you are killing me cheif..
Trying to figure this deal out.
Its not like a real dyno is the same as working on desktop dyno, where you can make it say whatever you want.
Besides I run a monster tach, got a problem with that?

[78Eliminator]

Dude, you are killing me cheif..
Trying to figure this deal out.
Its not like a real dyno is the same as working on desktop dyno, where you can make it say whatever you want.
Besides I run a monster tach, got a problem with that?
Your monster tach is too small Morg. What you need, daddy-o, is a tach with a face as large as a moroso professional degree wheel. Then the people in the grandstands will know exactly how many rpms you’re turning as you blow through the finish at 80, with that motor that just dynoed @ 2000HP and 180 VE.

[Morg]

As LVjetboy used to say, you have a social BS problem.

[Blown 472]

Your monster tach is too small Morg. What you need, daddy-o, is a tach with a face as large as a moroso professional degree wheel. Then the people in the grandstands will know exactly how many rpms you’re turning as you blow through the finish at 80, with that motor that just dynoed @ 2000HP and 180 VE.
Heeheheheh. But don't forget too that the tune up you got on the dyno in the nice cool room aint going to cut it in the 120 degree humid day. :rollside:

[steelcomp]

Ok,
I will agree that a dyno will tell you where you are making the power & where to set your deal up. That is basic.
And like you said you don't race dyno's.
Tell me this, The dyno is calculating how much power you are making & also telling you what the VE numbers are. Would'nt the calibration of the dyno be determining these numbers?
Is the operator setting the calibration??
Are you ever going to see those conditions in the real world???
The airflow going into the motor is measured by a flow meter. That's calibrated by the manufacturer. The vloume of the engine at any given RPM is calculated...not much you can change there.
It dosen't matter if you're going to see them in the real world or not. These guys use dyno's as a tool, not a toy. Real world coinditions are always changing. It would be impossible to know just what the effects of your modifications were if you didn't have some sort of baseline, and this is called sea level. You have two sets of numbers on a dyno. Actual and corrected. The actual numbers will change with the conditions, and without a correction factor, would be useless. Corrected numbers on a dyno bring everything back to the same page so that accurate comparisons can be made. If you know you need to run a certain mph and et, you can calculate how much hp you need. Depending on how much $ you have invested, you might want to know the output of your engine before you go racing. Dyno's also serve as a tuning aid. When I built my 467, I built a pair of hybrid carbs, and really had no idea where we would be AFA tune up. On the dyno, you can see all the info you need in order to know weather you're safe or not. Interestingly enough, there was a little mis-communication and I had my float levels set way low. On the first pull, the motor went dead lean...over 20:1 afr. Had I been at the lake, I would have had a nuclear meltdown in a second. Steve Brule' and Dave Ebbert both saw it instantly, and stopped the pull. No harm done. Good operators. 18 pulls later, and I knew exactly what kind of power I was making, the best timing setings, the best jetting, I found out my headers made more power than the test headers, and that my scoop cost me almost 40hp. Regardless of the numbers, that was all valuable info.
Some like big numbers for bragging rights. That's fine. They don't get it. Some like big numbers because they show some serious dedication and hard work, and as a result, they have a reason to brag. But they are looking for results, not bragging rights, and messing with the calibration on a dyno just to get bigger numbers would be totally counterproductive for them.

[Morg]

Steel,
Excellent points, What you stated is exactly what I beleive a dyno should be used for. Try to imagine setting up an EFI without a dyno, huge waist of time.
People need to remember that it is just a tool.
But, at the same time toting huge numbers on a dyno still is worthless. You will never see it in the real world.

[Morg]

BTW- how did you test the scoop without loading air into it???

[steelcomp]

Steel,
Excellent points, What you stated is exactly what I beleive a dyno should be used for. Try to imagine setting up an EFI without a dyno, huge waist of time.
People need to remember that it is just a tool.
But, at the same time toting huge numbers on a dyno still is worthless. You will never see it in the real world.
That's not true at all. The first race at Ming this year, there were conditions early Sat. where the air was below sea level. Most of Sat it sat right around 500'. You can bet that if you tuned your motor at a DA of 3000' ( hypothetical actual conditions in the dyno room) you're going to need that info and make a jet change. On a day like that at Ming, you're going to be putting that "corrected" sea level power right to your prop, less gear box drag, strut bushing, etc. That could be as much as 75-80 more hp. I wonder what set up changes you'd need to think about?
The "toting" part I agree with. (unless it's me doing the totin') :D

[steelcomp]

BTW- how did you test the scoop without loading air into it???
We didn't. We tested it thinking that at very least, a scoop shouldn't cost anything in power sitting still. This one did...big time. Would it pick up with more air flow? Don't know. All we know is it cost airflow and the BSFC went down...motor was leaning out. We think maybe lack of carb signal due to poor air distribution inside. We fattened it up a couple jet sizes, and picked it back up about 50% of what we lost, but that's not enough, and only a bandaid. Maybe the opening just wasn't big enough. Maybe this, maybe that...all I know is that scoop isn't going back on that motor. I'd have never known that without the dyno.

[Morg]

You bring up another reason why guys need to remember why the dyno is just a tool. You need to be able to tune in real world situations. Better or worse.
And speaking of real world, How do you set a fuel & timing curve with a dyno that will not load the motor in the same way the application will. I could see how a jet would be pretty close, but in my flatt the rpm could see 7500 at the hit with prop. burn, then pull down to 6700 & back up to 7400

[Morg]

We didn't. We tested it thinking that at very least, a scoop shouldn'rt cost anything in power sitting still. This one did...big time. Would it pick up with more air flow? Don't know. All we know is it cost airflow and the BSFC went down...motor was leaning out. We think maybe lack of carb signal due to poor air distribution inside. We fattened it up a couple jet sizes, and picked it back up about 50% of what we lost, but that's not enough, and only a bandaid. Maybe the opening just wasn't big enough. Maybe this, maybe that...all I know is that scoop isn't going back on that motor. I'd have never known that without the dyno.
Speaking of ram effect. I know its going on a jet :D , but you have to think you will get more air through at speed.

[steelcomp]

Speaking of ram effect. I know its going on a jet :D , but you have to think you will get more air through at speed.
True, but if it's a distribution problem inside the scoop, can you guarantee me that ramming more air into the scoop is going to fix it, and maybe not make it worse?

[Morg]

True, but if it's a distribution problem inside the scoop, can you guarantee me that ramming more air into the scoop is going to fix it, and maybe not make it worse?
Nope, but this is what I mean by real world. Things that cannot be told in a dyno room. Seems like someone who is so into the theory of engine dynamics would need to truly find the anwser to this one, maybe it will make it better.

[steelcomp]

Nope, but this is what I mean by real world. Things that cannot be told in a dyno room. Seems like someone who is so into the theory of engine dynamics would need to truly find the anwser to this one, maybe it will make it better.
Maybe isn't a chance I want to take. I'd rather start with a scoop that has no effect sitting still, than one that I know will cost me power. They'll both work better with air being forced into them, but I'd rather not start off with a 40hp handicap.
Good questions.

[steelcomp]

You bring up another reason why guys need to remember why the dyno is just a tool. You need to be able to tune in real world situations. Better or worse.
And speaking of real world, How do you set a fuel & timing curve with a dyno that will not load the motor in the same way the application will. I could see how a jet would be pretty close, but in my flatt the rpm could see 7500 at the hit with prop. burn, then pull down to 6700 & back up to 7400
Dyno's can be programmed to give a specific sweep rate to simulate acceleration. If all the conditions you desceibed above are under full throttle, then the tune up only needs to correspond with the rpm, regardless of going up or coming down. You'd certainly want to focus on that rpm range when doing your tuneup.
What about out of the corners?

[cstraub]

There are 2 types of dyno's. One is used for R&D. This type is used for tuning combinations, trying new parts, "out of the box thinking, all for the common goal of learning. This type of dyno gives you a baseline from which you should be able to tune your engine at the track for optimized performance. It also enables one to set up the rest of the boat or car to work with the powerband at which the engine operates the best.
The 2nd dyno is used for M&S. . .Marketing and Sales. This dyno is used to produce numbers to sell engines and/or parts. Our own government gives the OEM a fudge factor of +/- 10% on HP ratings. Americans love power so the engine that makes 300HP at 5500 is much more marketable at 325HP at 5500. These dyno's create bragging numbers and very happy customers in the shops, but when it comes to actual performance of the engine in the application a lot of times the customer is dissapointed but is confused because the dyno numbers say this but the speedo says other.
It all comes down to will your combo run the number.. . .period. And if it does it doesn't matter whether you have 600HP or 700HP.

[TIMINATOR]

Steel: I have found the same thing on scoops and am wondering which one it was you had issues with. I believe that most boat scoops were designed before flowbenches and dynos came into popular use, and the biggie..... the carbs were smaller too! We now have out of the box 4150s that flow what only a Dominator could flow a few years ago! Back in the day,a 750 was a big carb and having a stroked BBChevy was a real big deal. They are common now, but I haven't seen any new, bigger scoops to go with the bigger carbs and motors. My Dominator scoop sits under 3 years of dust on the shelf because it hurt the top end of the Daytona, I paid big bucks for it. The flowbench agrees with my findings, but I won't sell it because I wouldnt stick somebody else with something that doesn't work. The Machinery handbook has the impact pressure for air velocity, I will post later if I get time or maybe someone else can first. I believe at about 120 mph or 140 mph it was .1 lb. definatly not enough to make up for that 40 HP! TIMINATOR

[GUGS102]

I found out my headers made more power than the test headers, and that my scoop cost me almost 40hp.
Steel comp -
I had the same result, although I was running on the water with a roller 489 and HP 950. Picked up 2 MPH roughly the same 40HP. Out of curiousity, which scoop were you running? I have a stainless dooley,basset etc.
I never understood the physics, but now it makes more sense. Any one else have similar results with the scoops. I think they look great but not the most functional. Although I think the best use for them is to turn around when the water,rain,sleet gets really bad and you are trying not to inhale H20 in the motor :) .
Gugs

[Morg]

There are 2 types of dyno's. One is used for R&D. This type is used for tuning combinations, trying new parts, "out of the box thinking, all for the common goal of learning. This type of dyno gives you a baseline from which you should be able to tune your engine at the track for optimized performance. It also enables one to set up the rest of the boat or car to work with the powerband at which the engine operates the best.
The 2nd dyno is used for M&S. . .Marketing and Sales. This dyno is used to produce numbers to sell engines and/or parts. Our own government gives the OEM a fudge factor of +/- 10% on HP ratings. Americans love power so the engine that makes 300HP at 5500 is much more marketable at 325HP at 5500. These dyno's create bragging numbers and very happy customers in the shops, but when it comes to actual performance of the engine in the application a lot of times the customer is dissapointed but is confused because the dyno numbers say this but the speedo says other.
It all comes down to will your combo run the number.. . .period. And if it does it doesn't matter whether you have 600HP or 700HP.
Thats what I have been talking about.

[Morg]

On the scoops I would definatly agree that the scoop could have a huge effect.
My point being how can you test a scoop in a dyno room. Yes you can see how one will perform better & probably cause less turbulance to the air entering the carbs. But how do you know how either scoop will truly perform until you run the thing?
Tell me this, do you think Gregg Anderson installs a scopp on his motor in the dyno room??

[Morg]

Dyno's can be programmed to give a specific sweep rate to simulate acceleration. If all the conditions you desceibed above are under full throttle, then the tune up only needs to correspond with the rpm, regardless of going up or coming down. You'd certainly want to focus on that rpm range when doing your tuneup.
What about out of the corners?
So you can program in the sweep rate, but how will the dyno know the load on the motor?
Yes you can tune for a specific rpm, but again the motor load will effect the fuel curve.
As far as rpm out of the turns, no way of knowing until you run the course on race day & what lane you end up in.
As an example, the first time Tedesco ran the dual prop. deal at ming, the boat left hard & popped the blower off as soon as the props hooked up. Real world situation. Bigger load, needs more fuel. How can you tell a dyno what the load on the motor will be?

[78Eliminator]

I have a story for you. I worked with a guy a few years back. He bought a supercharged mustang cobra brand new. Shortly after, he became a member of some mustang forum, much like ***boat. He started getting ideas about what to do and asked me if he should go pay for a dyno session before he started so he would have some kind of idea about what the changes would really do to his car. I told him to forget about the dyno, and spend the money on a helmet and go to a track and get some 1/4 times. Like most people who ask for advice, he really just wanted me to tell him "Yes, go baseline with a dyno" and that’s what he ended up doing.
So, he was doing it all. Buying the throttle bodies, the smaller supercharger pullies, the computer remapping hardware. Bolt on junk. No real idea of what he wanted to do. No application in mind. His goal, was to impress a dyno. Every time he bought something, he took a trip to the dyno. He would bring in the numbers to work with a smile on his face. Bragging rights. He posted them on the internet too. But he complained that his car just didn’t feel right. That despite the numbers, it felt like a dog. That after all this time and money, and even a dyno sheet telling him that he was more powerful, he still felt like the old girl was not what she was right off the car lot. And that is when he learned the powerful lesson of application. He never even decided what he wanted to do! Want to drag it? Want to have a 200 mph car? What the hell did he want? For some people, that sheet is good enough. For others it’s a marketing tool, and some people use it like mentioned before, for R&D.
Summary: If you are building a motor for drag racing, the best place to do r&d is at the track. If you are building a motor for a piece of paper, why not make that paper a time slip?

[steelcomp]

So you can program in the sweep rate, but how will the dyno know the load on the motor?
Yes you can tune for a specific rpm, but again the motor load will effect the fuel curve.
As far as rpm out of the turns, no way of knowing until you run the course on race day & what lane you end up in.
As an example, the first time Tedesco ran the dual prop. deal at ming, the boat left hard & popped the blower off as soon as the props hooked up. Real world situation. Bigger load, needs more fuel. How can you tell a dyno what the load on the motor will be?
The dyno is only a measuring device. Had they had Tadesco's motor on a dyno, and simulated a run at full throttle, they would have seen the fuel requirements for that motor at any given rpm under full load. You can sweep a dyno up, and you can sweep a dyno down, ultimately stalling a motor. That's full load. You can stop the dyno at a given rpm for steady state readings. At full throttle, the load on the prop that limits the motor to a given rpm is no different then the dyno limiting the motor to a given rpm. A load is a load, and if you think of it from the motor's standpoint instead of the load standpoint, the motor dosen't know if it's hooked to a dyno or a prop or a jet or a transmission and a pair of slicks. At full throttle, at any given rpm, the motor makes X amount of power, and requires X amount of fuel to do it. It will take the same load to pull the motor down, weather on a dyno or the race track. A lot of time and sffort is spent in R&D shops to as closely as possible simulate actual track conditions in order to address the very questions you're asking.
None of this, BTW, is in search of "big" dyno numbers. Again, it's just using the dyno as a tool to gather information otherwise either difficult or near impossible to gather otherwise. Results at the track are the ultimate indicator.

[steelcomp]

Morg, to give you more of an idea of what dyno's can do, here's a quote from Larry Widmer regarding pro stock engine development, and this was written in June of '98. (hope I don't get in trouble for this)After installing all the "good" stuff, we’ll do a quick run in to re-torque and reset the valves. The next hour is spent installing pressure transducers for each cylinder, exhaust temp. sensors, and chemical analysis probes in each primary tube, correct air ducting and inlet temp. and volume measuring instruments, and also the fuel flow and all normally used sensors. We have the ability to not only adjust carb mixture remotely, but we also can re-map the ignition timing. Dyno’s have come a long way during the last twenty years, and . Dyno’s have come a long way during the last twenty years, and we’ve attempted to stay on top of the game, as the more you can simulate in the dyno cell, the less track time is required. Aside from being able to program a drag strip, oval, or road course into the system, we also simulate G’s by mechanically tilting the entire dyno / engine combination. For lateral G. the engine is all we tilt.
We now have the ability to not only map cylinder pressure from each cylinder vs. crank angle at all rpm., analyze the combustion efficiency by looking at the gasses that are spent, but we can also read the torque of each cylinder during the tests, and when the test is complete, we can down load, and determine where we need to fine tune.

[Morg]

I just read on another forum all the same stuff Steel has been saying. It appears I was totaly wrong all the time.
I dont know what I was thinking??

[Fiat48]

There are 2 types of dyno's. One is used for R&D. This type is used for tuning combinations, trying new parts, "out of the box thinking, all for the common goal of learning. This type of dyno gives you a baseline from which you should be able to tune your engine at the track for optimized performance. It also enables one to set up the rest of the boat or car to work with the powerband at which the engine operates the best.
The 2nd dyno is used for M&S. . .Marketing and Sales. This dyno is used to produce numbers to sell engines and/or parts. Our own government gives the OEM a fudge factor of +/- 10% on HP ratings. Americans love power so the engine that makes 300HP at 5500 is much more marketable at 325HP at 5500. These dyno's create bragging numbers and very happy customers in the shops, but when it comes to actual performance of the engine in the application a lot of times the customer is dissapointed but is confused because the dyno numbers say this but the speedo says other.
It all comes down to will your combo run the number.. . .period. And if it does it doesn't matter whether you have 600HP or 700HP.
The bottom line is always the combo to run the number.
I can think of nothing more fun than to own one of today's high tech dynos,
have an unlimited supply of parts and combo's to try and just beat the hell out a motor to get the best numbers possible. The biggest thing would be the "why" factor. The learning why particular changes give certain results both good and bad. The proving of theories and disproving.
I'd truly enjoy that. But the neighbors would have me in jail for sure.

[TIMINATOR]

Steel: I am sure many of us would like to know what scoop lost you near 40 HP. I had a similar deal on the Daytona jet and would like a name or picture of the scoop in question. What about you Gugs 102? and I believe that Hotrod sprint mentioned a similar loss. anyone else? TIMINATOR

[Unchained]

Try to imagine setting up an EFI without a dyno, huge waist of time.
Once I got the O2 sensor I found that EFI tuning in the boat was a great way to go. You have the exact load on it that it will be pulling for a given rpm.
I had my son drive and hold the throttle at a constant rpm and I adjusted the fuel maps for every 500 rpm. That works OK up to about 4500 rpm and then the boats going too fast to watch the sensor and the screen on the laptop.
Then I datalogged the runs with the Innovative box and played it back and adjusted the fuel maps from that.
Once you've worked with EFI and see the degree of precision that you can tune to, it seems like you're handicapped with the lack of tunability with a carb and a mechanical advance distributor.
I'm collecting parts now to make my own bugcatcher / EFI hat to put on the blower on the V- drive Daytona that I got in January. I think it's going to be an easy swap. I'm not fond of roots blowers but this ones already on and it was recently rebuilt and repolished.
I found a used Haltech E6K unit with the harness for $ 500. that I'm going to be using.
I'll be making a thread of the assembly and tuning of it once I've collected all the parts.

[Morg]

Once I got the O2 sensor I found that EFI tuning in the boat was a great way to go. You have the exact load on it that it will be pulling for a given rpm.
I had my son drive and hold the throttle at a constant rpm and I adjusted the fuel maps for every 500 rpm. That works OK up to about 4500 rpm and then the boats going too fast to watch the sensor and the screen on the laptop.
Then I datalogged the runs with the Innovative box and played it back and adjusted the fuel maps from that.
Once you've worked with EFI and see the degree of precision that you can tune to, it seems like you're handicapped with the lack of tunability with a carb and a mechanical advance distributor.
I'm collecting parts now to make my own bugcatcher / EFI hat to put on the blower on the V- drive Daytona that I got in January. I think it's going to be an easy swap. I'm not fond of roots blowers but this ones already on and it was recently rebuilt and repolished.
I found a used Haltech E6K unit with the harness for $ 500. that I'm going to be using.
I'll be making a thread of the assembly and tuning of it once I've collected all the parts.
As youo know I have read a bunch on the EFI. Sounds like a cool deal.
Question, Has anyone come up with injectors big enough for alky?. I'm guessing somewhere in the 100 to 120 lb range.

[Unchained]

I'm using eight 160# / hr injectors and that's not enough for alcohol with a 540 ci engine.
One of the ways to do it with EFI is, in addition to the regular injectors, to have a couple nitrous / fuel solenoids right on the fuel rails and have them open at a set manifold psi and shoot the fuel directly into the manifold plenum with a jet in the line. I've also heard of shooting it right into the turbo compressor.
I personally don't see where any alcohol advantages outweigh the negatives unless someone really needs to make over 2500 hp.

[steelcomp]

Steel: I am sure many of us would like to know what scoop lost you near 40 HP. I had a similar deal on the Daytona jet and would like a name or picture of the scoop in question. What about you Gugs 102? and I believe that Hotrod sprint mentioned a similar loss. anyone else? TIMINATORTim, it's an old 70's Harwood style. Unfortunately, without further testing, it's pretty difficult to know exactly why the motor looses power with this particular scoop. I have lots of theories, but no data to back any of them. It may be the opening. It may be the venturi under the opening. It may be the relationship between the bottom of the scoop and the tops of the carbs. Who knows. This scoop may work perfect on another set-up. It was on a boat that set numerous records and won championships in Comp Jet back in '80/'81. (Dick Griffin in a Texas Tunnel called Thumper)
Here's a pic of the scoop. That dosen't necessarily mean it didn't have the same problems back then. Just some history.
http://www.***boat.com/image_center/data/520/1729scoop1.jpg
http://www.***boat.com/image_center/data/520/1729scoop2.jpg
Same scoop, 1978
http://www.***boat.com/image_center/data/520/1729Bakersfield1-med.jpg

[GUGS102]

Steel: I am sure many of us would like to know what scoop lost you near 40 HP. I had a similar deal on the Daytona jet and would like a name or picture of the scoop in question. What about you Gugs 102? and I believe that Hotrod sprint mentioned a similar loss. anyone else? TIMINATOR
Here is the scoop I lost the HP and MPH with.
http://www.***boat.com/image_center/data/520/2928P3300614.JPG

[DEL51]

I'm using eight 160# / hr injectors and that's not enough for alcohol with a 540 ci engine.
One of the ways to do it with EFI is, in addition to the regular injectors, to have a couple nitrous / fuel solenoids right on the fuel rails and have them open at a set manifold psi and shoot the fuel directly into the manifold plenum with a jet in the line. I've also heard of shooting it right into the turbo compressor.
I personally don't see where any alcohol advantages outweigh the negatives unless someone really needs to make over 2500 hp.
Max application, question? If it was a blower setup could a guy run injectors to the intake runners and on the top like the standard open loop designs? Also, could it be driven by one computer? I read an article about a pontiac builder, maybe butler, and they made an aluminum block. They wanted to test its limits and achieved 2800 hp using turbo/efi technology. I guess the block was fine and they are going methanol to see 3000+ using efi, FYI.

[Blown 472]

Max application, question? If it was a blower setup could a guy run injectors to the intake runners and on the top like the standard open loop designs? Also, could it be driven by one computer? I read an article about a pontiac builder, maybe butler, and they made an aluminum block. They wanted to test its limits and achieved 2800 hp using turbo/efi technology. I guess the block was fine and they are going methanol to see 3000+ using efi, FYI.
I think that motta is in his kids car.