EGT's

[Unchained]

There's probably some people who know a lot more than me on this subject so how hot is to hot?
With my turbo motor the EGT at a cruising speed is around 1350 but if I run at WOT 20 lbs boost / 6800 rpm for a few seconds the temp goes up to 1800 + eek!
So then I'm inclined to richen up the max rpm point on the fuel maps and the EGT's go down as well as the HP.
At the 1800+ EGT the motor pulls incredibly strong.
I never ran a EGT gauge before now and don't really know what is the norm. I've asked around and no one seems to be able to give me a good answer on the EGT's
Most say reading the plugs is the best and the EGT gauge is not the best way to tune, only a reference.
I think there is more power to be had here but I am cautious about the temps I have seen.
Maybe a turbo motor reads a lot higher EGT because of the exhaust backpressure?
Running 20 lbs boost relates to 20 lbs backpressure also.
I have the thermocouple mounted in the head about 1" from the exhaust flange.
Any input?

[Snowboat]

Don't know diddley, but I think you should be around 1,400'.

[LakesOnly]

Don't know what to tell you about EGT's in a blown application...
I ran EGT regularly when I raced normally aspirated motors. I relied on it extensively during testing...so much, in fact, that if my EGT wasn't working (thermocouple failed, etc.), I wouldn't even bother going out to test.
Used in conjuction with other readings, such as plugs, stopwatch, baro, even a dyno, etc., you can get a relatively accurate idea as to how to set up your motor for particular applications, races etc.
In my experience, for example, the use of a stopwatch, jetting and plug readings would set me up for a particular road course. All this time, I would watch my EGT and note the temp based on my fastest lap times. Then, as the day went on and the atmosphere changed, I could watch the EGT change and adjust jetting accordingly and stay on top of my game. Further, when I went to various other tracks away from home, jetting for max power became a snap because it was based on my knowm EGT temp at peak engine performance.
Different experienced people will give you wide temp variations as far as what is acceptable/maximum EGT. Personally, I'm known for being frugal and lean toward engine reliability. For this reason, I would usually run 1250-1300 farenheit but be perfectly willing to run as high as 1500 farenheit if the competition required me to do so. I never had a major failure even at 1500 degrees nor did I ever run into anyone else that did (of those others that read EGT).
Please remember that I have no idea how this experience with normally aspirated motors should reflect/compare to your blown motor. I would think, however, that if you are producing greater power with your engine at 1800 degrees, then you should probably be referencing all the other components that indicate just how your engine is taking it...such as plugs, oil temp, etc.
I would strongly recommend that you speak with some long-time professional turbo motor builders that have more experience at this and can help you determine what is right for your application. Ray Hall, Paul Pfaff, etc.
Good luck,
LO
[ September 07, 2003, 06:34 PM: Message edited by: LakesOnly ]

[bigkatboat]

I think you will find that 1600 F is the TOP of a motor that will LIVE. I've built a ton of turbos (ski race) and blowers (drag and ski race) and the 1800 F number sounds (like rolling a floor jack over you dick) bad. Once you realize what happened, it's too late to care. Play/ enduro motors will live at 1450/1550 F, and drag race only, who cares? Just load in another bullet, after this one melts. Have you tested you EGTs for accuracy? 1800 F sounds like a down payment on a new motor. (or at least the valves and seats) :cool:

[Mr.curious]

I am currently dealing with same exact thing, I just installed egts today, I installed them in manifold before turbo. I can tell you i Have been flying and building turbocharged airplane engines for years . peak lean is about 1700 degress any thing over that and things start to melt. I know if they are installed after the turbo the temp is around 150-300 cooler due to pressure. the gauges will vary in temps. I doubt your is reaching 1800 but it does definitly sound like its lean, lenghts and connections change every thing even soldering the thermal couple after bolting togther changes the temp a little. but as long as they read consistant thats what is important. I am going to test my boat monday night or weds morning and I will let you know the results. I am only running 10 psi of boost. But I am having some lean issues at cruise at 0 psi boost. I will let you know what mine read. I am sure if you do a plug reading you will find that it is lean on top end. Thats my two cents best of luck ,cause running a turbo motor lean only takes 3 or 4 seconds to melt. I have already melted a few sets of JE pistons Ken

[LakesOnly]

bigkatboat:
...the 1800 F number sounds (like rolling a floor jack over you dick) bad... :cool: Owww! jawdrop That's baaaaad!
LO

[Nubbs]

When we dynoed twin turbo gas motors, we would not let the turbine inlet temp get above 1600F. Something to keep in mind: for a turbine inlet temp of 1600F, the EGT's at the ports would be around 1350F-1400F. The EGT was higher at the turbine inlet than at the exhaust port. Your EGT at the exhaust port is 1800F, but your EGT is hotter at the turbine inlet.
Why do you say 20psi boost relates to 20psi back pressure? :confused: Did you measure it?

[Unchained]

Nubbs:
Why do you say 20psi boost relates to 20psi back pressure? :confused Did you measure it? [/QB]No, I didn't measure it but I was told that by the turbo guru that I bought some of the components from.
From some more asking around I've done evidently there is a problem that you can get with too rich a mixture called " stack firing " where lots of fuel is still burning going out the pipe. I'm thinking this is the problem I'm experiencing that is causing the high temps because if I richen it up slightly even just 7% the engine won't peak out. Then it seems the EGT went down not because the mixture was better but because the engine wasn't burning all the fuel and the top RPM was way down.
Even with the temps I've read I haven't noticed the headers or the turbine housings glowing red yet.
Of course I only held it at WOT for 4 or 5 seconds.
I've seen blower motors on a dyno pull and the headers were glowing red after 5 or 6 seconds.
Thanks for the input and opinions,
Keep it coming

[FastTimmy]

Unchained, Your are rite on track!
evidently there is a problem that you can get with too rich a mixture called " stack firing " where lots of fuel is still burning going out the pipe. Is your thermocouple at the header flange?

[Unchained]

[QUOTE]Originally posted by FastTimmy:
Is your thermocouple at the header flange? [QUOTE]
Yes,
http://www.***boat.com/image_center/data/500/220thermocouple-med.jpg
If it's still burning on the way out it would defininely read the hottest at the point where my thermocouple is installed.
I've been running it this way for a while now and it hasn't caused any problems but I want to figure out a solution. I always feel like I'm right on the edge of too rich to clean out.
If I hadn't bought the EGT meter I wouldn't have noticed the high EGT and just tuned it until it pulled the hardest and got the highest RPM to the jet pump(same thing). In a way I feel the EGT meter is messing me up.
It makes sense that less fuel would make less heat.
One thing I notice with this Haltech system is the range of adjustability you have.
With Carbs, changing jets makes very small incremental changes in the mixture.
With the EFI you can change the mixture by large volumes.
You can make monumental errors if you don't watch out.
At WOT / 20 lbs. boost the injectors are open 7.5 milliseconds per revolution and that's too rich.
There is probably the equivalent of less than one drop coming out of each injector per revolution.

[FastTimmy]

On my old set up I had my pyros about one inch further from the valve. THey were in the header tube. I would see 1500 most of the time when running hard. I had only seen a lean 1600 deg (lean with o2 meter)once and when I torr the engine down after about 50 hours I discoverd that I had ring butting with .025 of top gap on a 4.280 bore.
I wonder what the turbine inlet temp is?
Timmy

[Boozer]

Why are you running the thermo couple right there? I have always run the thermo coupler on an exhaust collector and gotten pretty accurate readings. If you were seeing a true 1800 your motor would be gone already.
The Haltech has a knock sensor doesnt it? Watch your knock count and that will tell you the whole story. If you are running hot you are running lean. Most likely you'll be getting some seriously high knock counts if your getting lean enough to hit 1800 EGT's.
One thing I have learned about tubro motors. Your engine will always pull its hardest right before it melts eek!

[UBFJ #454]

From the pic. it looks like your running Al heads.
With the sensor positioned the way you have it, it is sensing more of the heat generated by the adjacent cylinders than had you installed it 1 1/2 inches out from the flange in the header tube (either top, or, bottom). While an increase in sensed temp (above a header tube installation)would occur if one does such an installation as yours in a cast iron head, it would not be as much as in an Al head due to the greater heat conductivity of Al over Fe/Ni alloys. Also, your installation position is closer to the exhaust valve than is normally done resulting in higher temp readings.
Most EGT temp. data out there are from EGT's in the header tubes as described above. Not having any comparison data between the two installations, I can't say for sure, but, I suspect a good portion of your higher temp readings (above what is typically quoted) is solely due to the position of your sensor.
[ September 10, 2003, 02:11 PM: Message edited by: BEAR_454PE ]

[Dave C]

I usually run no more than 1400 but typically around 1300 in an N/A motor. I never used turbos or S/C.
The EGT sensor I used directed installation of the probe in the header tube 2 inches away from the header plate. (i.e. 2 inches away from the motor down the tube.)
the directions actually said to run the EGT on the dyno to correlate the temps against the highest output #'s and tune accordingly.
It also said the forced induction motors "typically" run higher temps than N/A.
[ September 10, 2003, 04:19 PM: Message edited by: Dave C ]

[bigkatboat]

Where is your spark timing ? Is the 'big fire' going out the exhaust, because the timing is late ? Late timing will cause high exhaust temps.

[Unchained]

The timing is at 32 degress at that boost level and rpm.
I'm convinced that the high EGT's that I've got are a result of unburnt fuel going out the pipe. I'm going to continue to cut back on the top end mixture and watch the plugs and the EGT's should come down.
It doesn't make sense that the mixture could go from too rich to clean out to too lean in a matter of just 5% to 7% of the fuel mixture at WOT.
I've already adjusted the fuel map and when I take the boat out this weekend I'll see what I get.
This is a situation where if I was running unleaded fuel I could use an Oxy sensor in the pipe and the Haltech box would tell me what the mixture was or I could run the system in the closed loop mode.
My goal is to run pump gas with a closed loop system but at the high boost levels I have now it's not possible.

[Unchained]

Since my last post on this subject I have repositioned the thermocouple to 1 3/4 " out in the pipe away from the header flange.
Same high temp readings.
I have been tuning from rich to lean and if it's too rich to clean out the temps are still near 1650 and the max rpm is down to 6200.
If I lean it out it comes on real strong and now turns the jet pump with the AA impeller to just over 7000 rpm with 20 lbs boost but I've seen EGT's up to 1900 degrees now. eek!
This is one of the reasons I still don't want to hold it WOT for more than 5 or 6 seconds because I'm afraid I'll have a meltdown.
From the HP/impeller chart that LV jetboy sent me It's probably near 1300 HP.
I never owned an engine that had balls like this before.
I have a brand new EGT meter and am still puzzled why I read so much higher EGT's than others who have responded and emailed me. (maybe the meter is on the metric scale :rolleyes: )
I've been considering a water injection system like I ran at the sand drags years ago.
I feel that my fuel system is bulletproof with a belt driven Aeromotive pump and a boost referenced regulator.
31 degrees total timing advance.
Running 110 octane fuel.
I feel like I should disconnect the EGT meter and tune by feel like before.
Any more input?

[Infomaniac]

Have you talked to any of the hard core turbo gurus that sell the equipment?

[SuperWrench0166]

http://www.sdsefi.com/techegt.htm
i think i would try another complete egt setup i would also run one in both sides so you can see if its same on each side.

[Unchained]

Superwrench, Thanks for referring me that information.
It was really enlightening.
Here's a quote,
" Many people think that the leaner you go, the higher the EGT gets. This is also incorrect. Peak EGT occurs at stoichiometry- about 15 to 1 for our purposes. If you go richer than 15 to 1, EGT will drop and if you go leaner than 15 to 1 EGT will ALSO drop "

[Infomaniac]

Unchained:
Superwrench, Thanks for referring me that information.
It was really enlightening.
Here's a quote,
" Many people think that the leaner you go, the higher the EGT gets. This is also incorrect. Peak EGT occurs at stoichiometry- about 15 to 1 for our purposes. If you go richer than 15 to 1, EGT will drop and if you go leaner than 15 to 1 EGT will ALSO drop " I was going to mention that. I have not had time to read the link.
Smokey proved that years ago measuring the rich/lean temperature using a torch. Give it a try. Easy to change while you look at the temp.
[ October 12, 2003, 11:57 AM: Message edited by: Infomaniac ]

[565edge]

Unchained,over 7,000 rpm with a double A.That is awesome.If you could leave your foot in it you would be flying.You might end up giving infomaniac a run fo his money.

[HeavyHitter]

Unchained, at 7000 rpm you only have 8.57ms at 100% duty cycle on the injectors. If you're running 43 psi fuel pressure there with 160 lb/hr injectors 7.5 ms is at 87% duty cycle or 2227 horses worth of fuel. take 250 off of that to drive the turbos and you've still got nearly 2000 hp. If the fuel pressure is higher so is your flow. 1800 degree EGT is a bit much. Should be in the 1600 degree range. I would suggest you put that engine on a dyno with a wide band O2 sensor so you can tell what's really going on. You've got way too much into that thing to melt it down. A $500 dyno session is well worth the money.

[UBFJ #454]

Now that you've verified that you get essentially the same reading 1 1/2 back from the flange, in the header pipe, put bungs in all the pipes ... if you don't want to buy more than two (2) EGT's (which I suggest) fine, simply move each of the two along even and odd banks and record readings. Then switch sides for the EGT sensors for a few pulls and compare. Look for the classical BBC characteristics and go from there.
O2 sensors on each cylinder would be much better in my opinion as I don't believe in tuning off EGT's ... I use o2's. My experience has been that EGT's provide a relative measurement, not an absolute. EGT's will however give you an absolute number and you'll know when you've Nuked a cylinder, or two ... something you'll know anyway.

[Unchained]

Thanks for the feedback.
Heavy Hitter, I'm running 42lbs fuel pressure at idle with boost referencing so at 20 lbs boost I'm running 62 lbs fuel pressure.
I would like to run an O2 sensor but they only work with unleaded fuel.
I've run the injector time down to 6.4 ms at 20psi boost and that's where I got the most HP and the highest EGT's.
At 7.5+ ms the engine won't clean out.
I know what you mean about the dyno tune but I would have to do it myself unless the dyno guy knew the Haltech mapping.
I'm going to be in Phoenix for the drags on the 25th, 26th are you going to be there? I'd like to meet you and Bear454.

[UBFJ #454]

Unchained - Look forward to meeting you. We'll be doing T&T on Thursday, then qualifying on Friday & Saturday and, hopefully racing on Sunday. Stop by and say hello.
Jak Young

[HeavyHitter]

Unchained, not sure if I'll be able to make it to the race at Firebird. At 60 psi your injectors are flowing 189 lb/hr. 2630 horses worth if you're firing the injectors evey rotation. Not sure if your Haltec has a cam trigger to run full sequential so I'm assuming the injectors each fire every rotation. If not then the hp numbers you've figured are close. I would say not though, since the TV 70's are real big and at 20 psi that thing should be a monster. My latest little pump gas turbo set up only makes 1100+ hp with 95 lb/hr injectors at 48 psi fuel pressure and 12 lbs boost with smaller TA 45's. That's at 6.17ms injector timing @ 6000 rpm. Had to turn the fuel pressure up to keep clear of the rev limiter factory set at 90% duty cycle at 5300 rpm where it made peak torque of 1098 ft-lbs. I would guess you're over the top with fuel.

[Unchained]

Heavy Hitter, You're talking a little over my head.
The injection is triggered by a Hall effect sensor and a crank wheel. I'm not running sequential injection, The setup is on multipoint so as far as I know It fires all the injectors every time around.
The Haltech dealer told me that sequential wouldn't really benefit my application.
I thought I had plenty of injector capacity here but the datalog doesn't record duty cycle, you have to watch it on the screen which isn't possible while at WOT.
With the regulator set at 42lbs like I have and the boost referencing at 1:1 the actual fuel flow / pressure going into the engine is probably still 42 psi because it is shooting into the pressurized intake.
What's your phone number so I can pick your brain about a couple things?
You seem to have a lot of experience in EFI.
You can send it on a private message if you don't want to broadcast it.
Thanks,
Mark

[DEL51]

Unchained, I hope you can pick up a few pointers from the experts. I do know that if you can cool it down it will be awesome.On your next rebuild I suggest some use of coatings to help out.I had my dished pistons coated on the tops with a thermal barrier coating. When had my engine dynoed they used a wideband O2 sensor with the leaded race fuel. They have a life that is reduced by the lead additive.That was part of the cost included in my applicaton. I have a couple of questions for you and anyone else who cares to join in. If you measure EGT an inch and a half off the valve, is that the same temp seen by the valve face? Is there a temp diference between the seat and the face? I have spoken to Ken Dutweiller. He is a turbo expert with efi.I called him long ago about a blower setup I had, He's more into the v6 turbos but you may want to look him up.He is a very nice man and I bet he may be of some help.We are all behind you ,unfortunately I will not be at the races to meet you. I have some scheduling problems with the plant.I will see the money not spent on the trip on a Banderlog water controller.Good luck, Chris

[Unchained]

Del51,
I talked to Heavy Hitter and he is a wealth of information on turbo's and EFI systems.
Even though my engine has been running good he showed me where I've been putting way to much fuel to it at WOT from the start. He figures out the fuel quantity that the injectors will put out for a given rpm and calculates how much HP that will make. He told me that my setup should be putting out 1600 hp at 20 lbs boost once I get the mixture set right. eek! What am I going to do with all that? I probably only needed 12 lbs boost to make 1300 hp.
I need one of those wide band O2 sensors and that will get it exactly right. The boating season is about done here in Mi. so I won't be able to hook up an O2 sensor until spring now. Add to that the oil cooler that I need also.
Well my whole 1st season on this setup will have been spent tuning but I still ran the boat for 20 to 30 hrs and had a lot of fun with it.
When I had the blower/carb setup I never was sure I had the WOT mixture exactly right there either.
Mark

[565edge]

Unchained did you ever get a top speed number with the set up right now?

[Unchained]

Originally posted by 565edge
Unchained did you ever get a top speed number with the set up right now?
No, I never had my foot in it for more than 5 or six seconds because of the high EGTs that I haven't figured out yet.
I'm ready to pull the motor and check out the parts after I get back from Phoenix on the 29th. If everything looks good I'm gong to reassemble, add a wideband O2 sensor and put it on a dyno this winter. I found a guy an hour drive from here who can dyno up to 2000 hp.
I did datarecord a run with two of us in the boat (225 lb friend) cooler, toolbox, etc. and I matted the throttle at 20 mph gps and backed off at 95 mph gps and that was 5.5 sec.
I think with just me in the boat and running at the drags where I could cross the start line at a higher speed I could get past 100 mph in less than 5 sec.
It's all about the accelleration rate.
I don't really need to know the top speed.
Many others have run these hulls to over 130 in 1000'
They're braver than me.
Maybe next year.
Does anyone know, at what speed are dragboat racers crossing the start line?

[Snowboat]

Say Unchained; I know this is off the thread, but I see you are active lately. Weren't you the one that posted a special exhaust system a couple of years ago? I'm thinking you were the guy that lived on a lake, in a quiet subdivision, and fabbed some tubing that ran over the transom and down close to the water. If you are that person, could you post the pic again. Might spark some conversation about noise laws, and ways to combat them. Thanks.

[565edge]

Unchained i can not answer your question.I went 110 this weekend at the njba drags,I also heard there mph clocks where slow about 3-4 mph.That was at 7,000 rpm with a b impeller in my edge stealth.I would think you might be going around 30 mph when you go through the lights.My motor makes around 950hp on a decent tune up.

[Unchained]

Originally posted by Snowboat
Say Unchained; Weren't you the one that posted a special exhaust system a couple of years ago? I'm thinking you were the guy that lived on a lake, in a quiet subdivision, and fabbed some tubing that ran over the transom and down close to the water. If you are that person, could you post the pic again. Thanks.
That was me,
Some laughed,
Some applauded,
Either way it worked great and I am planning a similar setup on my current boat.
I plan on dumping the engine water into the pipes about 24" downstream from the turbos and then going aluminum tubing the rest of the way out.
I figure that the exhaust will end just behind the sponsons.
Underwater at idle of course.
http://www.childsdale-ind-prop.com/pictures/unchexhaust5.jpg
http://www.childsdale-ind-prop.com/pictures/unchexhaust4.jpg

[Snowboat]

Yes Sir! That's the one! A little more bracing, and a couple of butt ugly Flowmasters just after the headers, and we can all be legal. Think outside of the box. Thanks for posting.

[Unchained]

Well after over 25 hours use in the first summer on the new turbo setup and having shown such high EGTs for the three dozen + times that I ran it up to 20+ lbs boost / 7000 rpm I tore the engine down for inspection and found.......
..........
.........Everything looks normal.
valves and combustion chambers looked OK, no signs of meltdown or detonation.
http://www.***boat.com/image_center/data/500/220headinsp1-med.jpg
Pistons look good,
http://www.***boat.com/image_center/data/500/220blockinsp1-med.jpg
Even my intercooler core held up good and the bottom side shows no signs of fins blowing out.
http://www.***boat.com/image_center/data/500/220intercoolerinsp1-med.jpg
This is good because when I met Tom Papp at Firebird and he told me that some people were having problems with intercoolers losing fins at above 12 lbs boost level.
Even though I had some challenges this year learning the Haltech EFI system I'm overall happy with the results.
If I had it to do over again I would run the engine on a closed loop system at 10 lbs boost with unleaded fuel until I had the mapping down and then switch to open loop and run leaded gas to work with high boost.
Anyone need to make some major HP?
Everything in this picture for $ 3,000.00
http://www.***boat.com/image_center/data/500/220stheaderswturbos-med.jpg
I think that if someone knows how to tune an Enderle that these turbo compressors could be piped into the front of the Hat.
That would be less expensive than going EFI.
I need a new project and am ready to make another set of headers.

[Infomaniac]

SOLD !!! Hurry and get the engine out I will pick it up today :D
You might want to edit the post to say everything in "THIS" picture.
Looks like it is burning clean. Not much margin there.

[HeavyHitter]

Unchained,
Constant flow injection is as complicated if not more on a turbo system. You still have the typical bypass and low speed bypass, but you add a return diaphragm valve that is boost driven with with another high power circuit which really requires a second set of injectors. By the time you're done it's a wash and you really have to know which spring or bypass to change.

[GofastRacer]

Originally posted by HeavyHitter
Unchained,
you add a return diaphragm valve that is boost driven with with another high power circuit
Please excuse my ignorance here but are you talking about a high speed lean out??....:confused:

[HeavyHitter]

No high speed lean out would be the third poppet on a conventional system. This is exactly the opposite. It's a valve that sits at the tank and closes off the main bypass as boost level climbs. You balance that pressure with the "R" valve which supplies a secondary set of injectors or just more fuel to the primary set. In single set configuration the engine generally doesn't idle well since the injectors have to be big enough to hanld the whole fuel load. An engine similar to Unchained would run #10 vented injectors and #20 non-vented (secondary circuit). 110 pump or bigger and hang on.