Turbo's and nitros question

[billet racing]

Consider puting Nitros to the turbo motor.
Set up. 496 Chevy Twin Turbo
Builds 18 lbs boost at 6,000 rpm's
Concern with the fuel lines. 7 lbs fuel pressure. will the boost effect this?
Lying in bed the other night I invisioned the boost pressure keeping the fuel from flowing.

[keithmenard]

the way it was explained to me was you can't inject x pounds of pressure into that much boost.
I think the way to do it is inject the nos BEFORE the turbos.

[Unchained]

Consider puting Nitros to the turbo motor.
Set up. 496 Chevy Twin Turbo
Builds 18 lbs boost at 6,000 rpm's
Concern with the fuel lines. 7 lbs fuel pressure. will the boost effect this?
Lying in bed the other night I invisioned the boost pressure keeping the fuel from flowing.
What kind of setup do you have ?
Blow through or draw through ?
If it's a draw through, boost isn't going to affect the fuel flow because the carb is ahead of the turbo.
A carb base plate nitrous setup would probably work well.
What's the reason for the Nitrous? Do you have a lot of turbo lag?
If you need more power can you just up the boost and recalibrate the carb?

[billet racing]

Draw through.
Race Aero system. Water cooled Risers, carbs sit ahead of the turbos. Feed into common pleneum, with intercoolers.
would need two injection plates to mount them under the carbs and ahead of the turbo's
Why? Because. Never fast enouph.
Using this as a lake boat. Real pleased with the setup. Want to go faster. The other idea we are kicking around is a new hull just for racing. and Blown acohol.
It's a horrible disease
Jerry

[Unchained]

Jerry,
Did you look up on an impeller chart and estimate the power you're making with 6000 rpm and ??? impeller ?
I would think that 18# boost into 500 ci should be over 1100 hp.
Does it seem to be making that much ?
Maybe you can change / optimize your tune and get more.
Just my opinion here but nitrous is great for racing but the constant changing and refilling the bottle gets to be a pain. With two 150 hp carb base plates a 10# bottle will last one minute.

[ttmott]

Can I watch?????
I would have to run the numbers but off the cuff the best advantage is the "pre-densification" of the charge theoretically allowing the compressor to pump more consequently higher boost. The big concern is if the O2 should disassociate before the combustion chamber (probably wouldn't) and gernade your entire turbo and downstream assembly. The really big question is if you would be outside of the turbo's map causing a destructive surge condition with the dense mixture.
I say step up to a 500 hp fogger system cap the waste gates and report back!!

[billet racing]

Running an A/B impeller. 32 degree advance Holly 750's out of box, changed jets some. Running a tad rich in my opinion, (playing it safe there)
MSD does not have boost control. Has a switched retard I can apply. adjustable.
I estimated around 900+ HP Have not Dyno'ed for optimum power set up.
21' Daytona, lake setup.
Any suggustions?

[carreraboat]

Just curious what cam you running on your setup?

[billet racing]

I'll post up all the technical info on tomorrow.

[Unchained]

Running an A/B impeller. 32 degree advance Holly 750's out of box, changed jets some. Running a tad rich in my opinion, (playing it safe there)
MSD does not have boost control. Has a switched retard I can apply. adjustable.
I estimated around 900+ HP Have not Dyno'ed for optimum power set up.
21' Daytona, lake setup.
Any suggustions?
Oh no, I feel another sermon about O2 sensors coming on..................
Here's a quote from a tech article,
"Extensive testing with laboratory quality instrumentation on aircraft engines universally indicates that best power is NEVER made at AFRs richer than 12 to 1."
I wouldn't retard timing unless you're sure it's causing a problem.
I need a knock sensor with my setup to help optimize ignition timing too.
Your jet pump is your dyno. If adjustments increase rpm you're going in the right direction.
So............What was Mr. Mott trying to say ?

[ttmott]

I was "injecting" a little tongue-n-cheek humor....get it......forget it.
The issue I was trying to explore was the fact that due to the N2O is delivered in a cryogenic state and under the carbs before the compressors a very large amount of densification will occur. The amount of squeeze (N2O) determines the amount of cooling. Secondly, the compressor design is critical with regards to the ratio of mass flow in LB/M and the pressure ratio P2C/P1C (inlet / outlet) (refer to the compressor map for your turbo); as flow increases and the pressure ratio decreases the compressor enters into an area known as stall where it is unstable and will self destruct. All of the data for existing turbo maps are based upon ambient (or close to ambient) conditions. Now let's double or triple the density of the incoming charge; the surge line which may have been at 15 LB/M at a pressure ratio of 1.8 is now at 5 or 6 LB/M at a ratio of 1.8. This also negates the fact that the charge is heated after the compressor further amplifying the situation; you may say it is heated anyway but the physics reveal that heat transfer is not constant with respect to comparative temperatures and densities.
Nitrous Oxide provides two factors for increasing power one which already discussed is the densification of the charge allowing to pack more fuel/air into the cylinders and the second which requires the additional fuel is the release of the oxidizer or the extra oxygen molecule. N2O when under pressure with temperature will disassociate the nitrogen allowing more oxygen for a fuel burn. Consider the pressure / temperature downstream of the turbocharger and the increased possibility of a detonation (something I really know about). I doubt this situation may exist but in the early NHRA days when the crazys tried exotic fuel mixing and N2O injection with forced injected engines parts were flying all around the spectator stands and the pits. NHRA put the stop to nitrous / supercharge situations.
I would say, however, the entire situation changes if the N2O was injected at the cylinder head port where the turbocharging dynamics have become steady state.
Like I said, I'm interested in seeing what happens with a draw-through setup 500 HP N2O fogger kit and cap the waste gates. Make sure you get video....
Tom

[ttmott]

OOPS I went backwards
did say:
Now let's double or triple the density of the incoming charge; the surge line which may have been at 15 LB/M at a pressure ratio of 1.8 is now at 5 or 6 LB/M at a ratio of 1.8.
should say:
Now let's double or triple the density of the incoming charge; the surge line which may have been at 15 LB/M at a pressure ratio of 1.8 is now at 25 or 30 LB/M at a ratio of 1.8.

[whale]

Billett Racing.......can you post a picture of your setup. I may have the same system on a 21 foot Rayson Craft. I just bought this boat and I am intrested in learing about this setup..........Thanks, Wayne

[steveo143]

It would be easy to mount a carb baseplate system between intercooler and intake manifold.
steveo143 aka dimarco21 II.

[Unchained]

It would be easy to mount a carb baseplate system between intercooler and intake manifold.
steveo143 aka dimarco21 II.
Steveo,
If you did that you could avoid the problems that ttmott is explaining in the most heady engineering terms :confused: but then you would be injecting your fuel and nitrous into turbo boost pressure and would need to have boost compensated fuel pressure for the base plate. Example 7# fuel pressure + 18# turbo boost = a fuel pump that can deliver 25# of pressure for the base plate alone. The fuel pressure also would have to rise with the boost and not all at once.

[billet racing]

Cam specs.
Lift Intake .731 Exhaust .727 @ .18 valve adjustment
Duration Intake 290 Exhaust 286 @ .020 lift
Duration Intake 257 Exhaust 253 @ .050 lift
Lobe seperation 114
Solid roller. Comp Cams
496' tall deck Merlin Alum heads, 320's 8.2-1 comp.
Does this help you?

[carreraboat]

That does help just doing a little reaserch for my setup

[carreraboat]

how often do you find yourself running your vavles

[billet racing]

I'll post up a picture soem time next week. Need my sone to help with this.
Run my valves? Do you need to do that?
Actually, often. It's a pain getting those valve covers off with the upswept center riser exhaust manifolds. Depending on how hard we run, how long. Good set of stud girdles help. Always before any race, and afterthe weekend to check for any carnaige. Catch it early, so I have time to repair. Keep a spare set of springs and rollers with me. Check the whole valve trail as I have had rollers go bad as well.
Have run at Havasu for a long weekend. Actually ran 3 drums(55 gallon) of fuel through her and no problems. Every so slight tweeking if needed.

[Unchained]

Billet Racing,
Have you done any research into the turbo size you're using that came with the Race Aero setup?
There could be some restrictions / limitations there. I'm thinking that any of the turbo kits out there may have been made conservative rather than for max power.
Have you tried putting a pressure gauge in the exhaust to compare the exhaust backpressure to the boost pressure ? That would identify a too small turbine housing problem.
It seems to me like you should be turning that AB impeller a lot higher rpm than 6000. My engines a larger displacement at 540 ci. but I'm turning a AA to 7000 with 20# boost. I'm getting 30# backpressure to make 20# boost.
http://www2.***boat.com/image_center/data/520/220datalogoct05.jpg
Good luck
Mark
616 813 7237

[HeavyHitter]

I agree with Mark 18 lbs of boost is a lot for the rpm you're turning. You might just be revving the snot out of the turbos. As far as nitrous the way to install it is by welding a port to the compressor housing inlet. 1200 psi of gas pressure does wonders for spooling up a turbo fast. Aim the spray at an angle to the compressor wheel blades. It's a real rush.