Baseline Dyno acheived, FINALLY

[rayaapp2]

Its been around 4-5 months since I said I was going to do it. I finally got the car on and made two runs at it with little to no tune. The engine is RB25DET from a 94 R33. I built my own 3" mandrel bent exhaust system with a Gredy straight through tip muffler. The only other non-stock/OE part is the intercooler. I have a million miles of pipe with multiple, excessive bends to fit a NPR Isuzu box truck intercooler.

 

So after 5 cars cut in line and pulled up on the Dyno I finally got in at the last minute and made my two runs. Both runs ran far to lean and started to pop at about 6400 rpm.

I actually walked away from this with a smile on my face because I realized that I made more power than I had expected to. Also I know there is much more power waiting to be unlocked in a tune session.

 

 

So that's exciting to me. Now Im off to find out why Im so lean still.

[240zdan]

im suprised the engine is still alive with an afr like that.

[rayaapp2]

im suprised the engine is still alive with an afr like that.

 

It doesnt go there until you load the engine in the upper rpm range as you can see from the graph above. So under normal driving the AFR is verging ok and closer to 13.5:1.

[240zdan]

If it were me, personally, I wouldnt drive the car, or at least under no circumstances hit boost until I'd have figured out what the issue is. Once I have an idea of what the issue is head back to the dyno and try again.

Do you have any pics of your setup? What pump are you running? Intank, inline, surge tank, fuel cell?

[streeteg]

ya those a/f rations are crazy. My baseline dyno was 214whp not getting above 11s

[rayaapp2]

Well I am running a stock setup. I was running the R33 fuel pump for a while then I switched to the Q45 as it has the same rating as the stock R33 Rb25det pump.

 

The return line on the R33 is tiny. Its almost a returnless system. I put a restricter in the return line to make it 4mm. Then I threw it on the 5 gas analyzer and started to tune. I have a APEXi SAFC II to tune with along with Nissan Data Scan on a lap top. So I tuned the low end in at no load(I know but whatever). I pulled off the silencer on the back at this point. Then back on the Dyno today to make 13 more runs. I'll try to give you a walk through on my tune and runs.

 

The first 2 or 3 runs were total crud. Something like 140hp. We didnt bother printing them out. We used them to start tuning the AFR in. The next few runs are here:

 

 

Closer with the AFR. Not really there yet though. I did make the most power I would all day at 252hp. But the miss is still there. So I called it quites for lunch and went down to the napa store and bought cheap copper core plugs that were rated 1 step colder than stock. Its pretty warm today and my car was heat soaking during lunch so we got back on the dyno and decided against cooling it down just to stay consistant with the ONE change at a time rule. During these runs we made some fine tuning after each pull. You can see the slight changes.

Here is what I put down with the next 5 runs.

 

 

Very consistent if you ask me and good numbers for a mostly stock setup. There is still some power hidden in there. More tuning will have to be done.

[240zdan]

it STILL looks LEAN.

13:1 AFR under boost? That cant be good. I would shoot for 13:1 N/A, 11.5:1 Boosted.

I know you are still working on the fueling issue but still.. thats lean as hell

It almost looks like the higher you rev, the better it gets.

Maybe its a maf issue?

[rayaapp2]

Yeah I have read a few posts about the MAF being to close to the turbo inlet and getting strange disturbances.

 

Mine is within 8" currently but will get moved when I change the intake and intercooler setup. It will let me move the filter out of the engine bay and the MAF closer to the radiator support.