Fueling an HE351 turbo on a 12 valve (Kind of long)

When I was playing around with my drive pressure gauge, drive pressure was more closely related to RPM than boost. 40psi at 2000 rpm was less than 50psi drive pressure. 40psi at 3500 rpm is closer to 65psi drive pressure on my setup.

While it's true that drive pressure steals horsepower, the added benefit of more boost results in more net HP to the wheels but admittedly efficiency decreases. Believe it or not, you will continue to make more and more HP the harder you push a turbo up to the point of turbo failure.


This might not hold true for a 1/4 mile blast down the road since pushing a turbo that hard makes for super heated air that could possibly heat soak the charge air cooler. A heat soaked charge air cooler results in high intake air temps and only so much volume can fit in the cylinder before the valves close. Cooler air will have more oxygen so in the case of running down the track, a wastegated maximum boost makes sense.

For a 2-5 second blast on the dyno, I question the need for a wastegate on a single turbocharged non-nitrous assisted motor.
 
TheSh111t said:
Really? 60 PSI drive pressure? Isn't it true that the closer you are to 1:1 ratio (Bost to drive pressure ratio) the better off you are? I have also heard that high drive pressures can attribute to head gasket problems. Not knocking you for doing it, just trying to get an understanding. I will be running a set up kind of like yours, and I would like to know the things to look out for.
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High drive pressure is related to head gasket failure, but not in the direct sense. High drive pressure is usually a present when EGT's are high. High egt's weaken the head gasket. High boost and high timing create high cylinder pressure. High cylinder pressure blows head gaskets directly.
 
Thanks so much for the info. I can't wait to get mine going. I'm leaving for Scotland first thing in the morning (For work) and I won't be home for 4 weeks. As soon as I get home I'll be trying my damndest to finish up my truck. Money has been the big hold back, but that problem should finally be solved (To some extent) If I get all of the parts, I'll probably have the truck up and running durring my 2-3 weeks off. I'll post any and all results when I have them. It is so cool of people to share there results with me, sometimes people hide things like they are some big secret (Not youu guys). Thanks again. I'm going to sign off for a while, but will check in the second I get back home. Good luck and great health to you all.
 
Big Blue24 said:
High drive pressure is related to head gasket failure, but not in the direct sense. High drive pressure is usually a present when EGT's are high. High egt's weaken the head gasket. High boost and high timing create high cylinder pressure. High cylinder pressure blows head gaskets directly.
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That puts things in to perspective. Thanks for clarifying.
 
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