Alpine951

I went to a dyno day last weekend with some 3000gt guys. I was having boost controller problems. I had the thing all messed up. I have been searching here trying to get an idea what a good curve should look like, or wether it should be a curve or a straight line assuming I can hold boost at 18 psi, which I can. Also when doing a dyno run how high should I run the rpms up when on the dyno. I told them 6k rpms and I was scared it was going to break, but after looking at some charts on here it seems like people run it up to 6500 and more. The shop is a heavy 3000gt tuner. The dyno operator told me they don't like to see the afr going up to 11.7 area in the high rpms but after looking here I see that 12.0 in the 6k rpm seem to be what people shoot for with the 951. is this correct? I am running a k27/6 that I just put in earlier this year running 18 psi and 65# injectors. When I go back to the dyno I want to know what to look for.

Evan70

Good curve (blue) versus bad curve(red). The good curve actually leans out a little on the top end, but it still give you a good idea of what it should look like.

Alpine951

So what is good about the blue curve?

RogueM3

It doesnt dip below 10:1, for one thing. A pretty good number is roughly 13:1 (seeing as how 14.7:1 is Stoich)...I would think a flat line at 13:1 would pretty much be the perfect graph.

Ian Carr

Evan, your curve is actually dangerous. Going into the 13's on the top of the rpm range is just asking for some thing to break. A afr should be close to a flat line between 10 and 12.8 (or around that). 13 and above in high rpms is running lean.

You basically want to get a flat line

Evan70

It doesn't actually go to 13, it peaks out at 12.8:1. It's just a little hard to tell because of the scaling on the graph. Still, even at 12:8:1, I agree that it's running a just little lean on the top end. That's why I dropped it back to 15psi for street use (that dyno was at 17psi).

Ian Carr

O yeah that looks like its in the 13's. Sounds good though

Black Arrow

Heres my graph. Pretty good with the old VR software chip!
Between 11.8 and 12.5:1 all the time. Small peaks at about 12.7:1



ZT2 log

special tool

HAHA - nice!!!!!!

For anyone that might not know what they are looking at - its nice.

Thomas - I can't quite see the BLUE digits - care to announce those numbers out loud for the class???

awilson40

Here's mine
Its at 12.0 at pk TQ, goes a little leaner to 12.5 around 5k then
richens back to 12.0 at redline.

Black Arrow

ST: Sure thing honey!

What about this picture? This is a 4th gear run, NOT tuned for best spool up either!


Still dont se the numbers? 14.7psi @ 3182rpm, 19psi @ 3368rpm!

special tool

AAAAHHH - getting too close....
You must have been driving up a mountain.

I have a 3109........