danny951

Ah yes, I remember the deltagate threads from several years ago.

Andial951

Thanks Tom....car feels a lot better.......here is the dyno graph with the A/F plot.

Andy

That's a good curve and it's a good camparison for what displacement will do. Your numbers at 13 psi are about what a 2.5 will do at 16-17 psi. The only comments I have are 1) it's running fairly rich and 2) your spoolup should be a lot faster. My 2.5 with K27/6 will hit hit 200 ft-lbs by 2750 rpms, your's isn't hitting that till 3100. Too much fuel will slow that down and I'd be looking for an exhaust leak also.

Andial951

Andy......thanks for the comments......you may be right about the exhaust leaks......I havent put all of the clamps on the exhaust yet so I suppose its possible it could be leaking.

I turned up the fuel pressure becuase it was getting lean at around 5500+ rpms. I suppose I need some kind of engine management systme where I can adjust the fuel pressure per rpm. Gettin a MAF with chips soon so we will see how that goes.

Do you think your earlier spool up could also be due to the MAF?

Andy

I can understand having to up the fuel pressure because you're encountering the same thing I did. My old Autothority chips which had about the same curve as yours would max out the stock injectors at 4000 rpms (I have an injector duty cycle gauge) and my a/f ratio would straight line increase from there due to more air but no more fuel. In addition you have less boost driving up the fuel pressure so yeah, you really did need to increase it. Your pushing all the hp you can with the stock injectors. I don't know who's MAF your going to get but buy some 55#ers (at least, probably 72's) to go with it, then you'll be fine with 3 bar pressure again, as long as you have good tuning for the displacement and boost. My vote would be for Vitesse here.

I would think that any spool-up advantage due to the MAF could be made up by your displacement. I would look for a header or crossover leak. I now have a big header leak I'm gonna have to do something about, saving up for the SFR S1 headers... Good luck.

Rick

My question exactly...anyone know for sure?

Tom M'Guinn

Andial,

The a/f ratio on that dyno run would make me a little nervous. At 5500 rpms you are close to 13:1. You dyno graph does not go all the way to redline, but I suspect with APE chips the a/f ratio would continue to lean out from 5500 to 6300 -- probably going over 13:1 and well into a range that threatens your head gasket. You can turn up the fuel pressure to help on the top end, but of course you will then make that mid-rpm range even richer than it already is -- this is the common pattern with APE chips -- without electronics, you have to run them overly-rich in the mid-rpm range in order to have enough fuel at high rpms. A MAF and digital fuel computer should fix that right up though.

Andial951

Tom,

Thanks for the comments. I am not running APE chips but i did have to turn up the fuel pressure to compensate for the lean at high rpms (i didnt want to push the car too hard so I asked them to stop the run at 5500). I did order the scivision MAF and I think I should have it next month. I am unsure but I think if I use their chips I wont need a fuel computer.....unsure though.....I'll have to get more info.

I will do another run after the MAF install and we will see how things work out.

toddk911

Anyone have an easy way to check for exhaust leaks? Specifically header/crossover?

MPD47

Wait, a wastegate that bleeds boost and cant decide if it wants to stay open or shut isnt a good design?!?! Dude must've been a rocket scientist....

juanchovidal

juanchovidal