My friend has the gt35/40 and he and another friend installed the gm 3bar map sensor on the car and made sure everything was tuned right with a wide band. But, the problem is the car runs great as long as you keep the boost below 18 psi, once it hits 18 psi the car acts like it hits a fuel cut (he's running a pfc with 850 primary and 1300 sec. injectors and the large nippon denso fuel pump). Does anyone have any thoughts on what is causing this. The injector duty is only around 75-77%. Could this fuel pump be maxed out as far as flow? Any help would be greatly appreciated.Thanks.

 

It could be the pump, but in that case you just wouldn't be able to tune the car well because your mixture would change based on electrical load. Get a fuel pressure gauge to be sure, but it is entirely possible that the Denso pump is running out of steam at high pressure. But it would yield detonation rather than an abrupt cut-out.

What is the PowerFC's boost setting set at? Even if you aren't using the PowerFC for boost control, it will cut if you go much over the setting that is stored in the PowerFC.

-Max

 

thanks. I'll talk to him this afternoon and find out if that is it. Thanks again.

 

1300cc are not enough and you'll need 850 primaries once you run over 22psi. And if you do run over 18psi, I wouldn't run the Power FC...IMO....its not proven, proven more so by your problems.

 

He already has the 850 primaries as I said in my first post.

 

oops, didn't see that. Get 1600cc secondaries and a damn good fuel pump.

 

Hey max, That fixed the problem. Man, thanks alot. We really appreciate it.

 

Max, the car is now running 20 psi on race fuel and is very strong. Thanks again.

 

Could this be Mike Smith's car???

 

Yeah, It's mikes.

 

Donald,What did he put down @ 20psi with the GT35/40. I'm going to try that myself, maybe even 22psi later this month.

K

 

Nocab72, we have not dynoed the car but the car is breaking the tires loose at 5500 in 3rd gear. The tires are 275/35/18's. We're wanting to get to a dyno as soon as we get a chance. And, get this, the motor is a factory mazda rebuild. No porting.