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herman pahls wrote:

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Does anyone monitor fuel pressure on their data logger?
Above 7000 rpm my fuel pressure drops from 50 to 42 psi (mechanical guage) in the higher gears on a 2008 Hayabusa.
GDRE felt that there should be very little if any pressure drop on an adequte fuel system regardless of load.
I am using a Mallory pressure regulator and just installed a new Bosch fuel pump and got the same pressure drop.
I am trying to solve a severe miss the engine developed above 7000 rpm at T-hill last week.
GDRE had just cleaned all 8 injectors after a low RPM missing problem.
Fuel filters are perfectly clean.
Any suggestions or similar expreience?
Thanks Herman

I totally agree with George on this issue. Using a Bosch pump on our turboed stroker Hayabusa with much higher demand than yours we would not see any drop in pressure at all. I don't remember whose regulator we have installed, unfortunately.

Marty

herman pahls wrote:

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Marty
You mentioned you have a Turbo Busa.
Would you consider mentoring me on Turboing my Busa?
Please call Oregon 541 404 6464
Thanks Herman

Ted gave you the long version; the short version is DON'T!! Buckets of money doesn't even come close to what it will take to get a serious motor running. We've got all the good pieces; billet cranks, Carrillo's, dry sump, custom this and that, and that's just the beginning. Maybe we made some of our own bad luck with the bored stroker motors we've been running, but we have had an unhealthy ability to vibrate exhaust manifolds and intake plenums to death, sometimes simultaneously and often multiple times in a weekend. At various times we've proven that it is possible to start melting an exhaust port, and we even proved that a minor oil leak can be a major conflagration when combined with a hot turbo. And I've spent a lot of time trying to come up with a fuel and timing map that will work from no-boost idle to 20+ lb. boost top end with driveable midrange, and haven't succeeded yet. We've spent a small fortune in datalogging gear, having found that it is useful necessary to track real-time air/fuel ratio, exhaust temp, fuel pressure, and boost pressure in addition to the usual stuff.

In three years we had one race where the car finished with full power, two more where it started with full boost and ended normally aspirated (but still running, sorta), and lots more that started with full boost and ended really abruptly. When it is on it makes probably between 320 and 350 HP, and will spin soft Atlantic tires really easily, but it is far more likely to mess with your head before it cooperates.

BTW, I did find out that we use a Bosch return line regulator, and I can say that the only variation in fuel pressure we see is related to the boost pressure reference, but I can say that when we are running at full boost with over 80 lb's of fuel pressure, it doesn't drop at all until Don lifts his foot off of the throttle. I did have one thought, though; are you running with the regulator between the pump and the injectors, or are you running a bypass regulator after the injectors? You would be better off with the latter, as it doesn't have to pass the full volume of fuel that the motor consumes, just the amount that it doesn't need.

If you ever come down to Laguna Seca and can make a stop on your way home contact me, maybe I could show you our setup. The shop is about midway between Laguna and Sears Point, just off of I-880.

Marty

Tom Bootz wrote:

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but we have had an unhealthy ability to vibrate exhaust manifolds and intake plenums to death, sometimes simultaneously and often multiple times in a weekend

Have any trouble keeping your oil cooler in one piece?

Sorry for the thread drift.

Nope, the oil cooler was never an issue. The oil that kept winding up in the intercooler was a problem, as it is difficult to clean it out!

Marty