[Guest]

Just dynoed yesterday afternoon. The car was running pretty good, except my spark plugs were bad so I couldn't turn up the boost very high. I got 591.4rwhp and 526 ft lbs on my last run, which spiked to 27.5psi. The max hp was actually achieved around 25.5psi or so; I had some boost creep a little before redline and my plugs started missfiring, so I called it a day. I just put in some new plugs and plan to re-dyno next weekend or the weekend after at 30 or 32psi. Some people seem to think my car was running really lean. I think it was running a little lean myself, but not that bad. Please check out the first dyno sheet on this page and let me know what you think about the air/fuel curve. I want to make sure I have it set right before I dyno at higher boost. Thanks.

http://www.directedengineering.com/dyno.html

-Paul

 

[Guest]

That is pretty lean once it came onto boost. 14:1 at 4000 is not good. It looks like it was goin richer cause your plugs may have been blowing out. Next time try to add some fuel from ~3000-4500. I'd go ahead and add ALOT in that range just for driving on the street. Smooth out that A/F curve and it'll make power quicker.

 

[Guest]

Ok, will do. Thanks. I'm not sure if my fuel system is working quite right. At around 25psi I started adding a lot more fuel but it didn't really seem to do much. Actually my air/fuel got slightly leaner when I added fuel, not sure why. My final settings on my gcc were +4, +4, +8, +4, +4. The +8 was for the 4100rpm range. I have an SP fuel system with 2 stock fuel pumps. You don't think they're working too hard are they? My main 40amp fuse for my fuel system melted during one of my dyno pulls. I'm pretty sure the reason for this is because there appeared to be a bad connection by the fuse holder, so I think it just overheated. So that's probably just a coincidence, but I thought I'd mention it anyway. I put in a new fuse holder with a 30 amp fuse (couldn't find a 40 amp) and it's been fine ever since. What are the ideal a/f ratios per rpm at say 30psi with 110 octane fuel on the dyno? And what are the ideal ratios on the street? Thanks.

 

[Andi]

I hope you didn't just run both pumps off the stock wiring. It's not up to the task. Run a thick wire from the battery for the pair of pumps and run them off a relay triggered off the stock wiring.

You should tune to 11.5:1 air/fuel ratio IMHO.

Andi

 

[Guest]

Andi-

No, I'm not using the stock wiring. I have a big 8 or 10 gauge wire coming from the battery that goes to a relay. You think I should aim for 11.5 at all rpms? Or only around the point where I reach max hp and thereafter? Looking at my dyno sheet, it appears that my turbo was fully spooled at about 4600rpm, so I assume at that point until redline my a/f should be right at 11.5 ideally? And up to the point it can be a little higher? I'm talking just for the dyno. On the street when I'm going through gears, my turbo is actually fully spooled around 3400-3800rpm, so I would probably have to shift the whole curve to the left by that amount.

-Paul

 

[Andi]

Andi-

No, I'm not using the stock wiring. I have a big 8 or 10 gauge wire coming from the battery that goes to a relay. You think I should aim for 11.5 at all rpms? Or only around the point where I reach max hp and thereafter? Looking at my dyno sheet, it appears that my turbo was fully spooled at about 4600rpm, so I assume at that point until redline my a/f should be right at 11.5 ideally? And up to the point it can be a little higher? I'm talking just for the dyno. On the street when I'm going through gears, my turbo is actually fully spooled around 3400-3800rpm, so I would probably have to shift the whole curve to the left by that amount.

-Paul

I tune the SFC-R for 11.5:1 from spool (~4000RPM) onward, and leave 3000 and below untuoched since the o2 sensor takes care of and learns those RPMs.

Andi

 

[Guest]

I tune the SFC-R for 11.5:1 from spool (~4000RPM) onward, and leave 3000 and below untuoched since the o2 sensor takes care of and learns those RPMs.

Andi

I've been wanting to ask this....

Since load on an engine differs from dyno drum to street, should one still aim for 11.5:1 ratio on a dyno? I've heard (many times) that an engine would run around a point leaner on the street than on a dyno jet. Therefore, to achieve a 11.5:1 A/F ratio, should one tune their car to 10.5:1?

Can anyone confirm this?

 

[houstonT]

On my black car, on the dyno, the car ran 11.7:1 and on the street it ran 11.9:1. I ran SLIGHTLY leaner on the street. Anyhow, per andi's advice, 11.5:1 is VERY safe, i personally would tune to 11.8:1 or so on the dyno. You should have a perfectly smooth a/f curve from the time the turbo spools all the way to redline...
Peter

 

[Andi]

I've been wanting to ask this....

Since load on an engine differs from dyno drum to street, should one still aim for 11.5:1 ratio on a dyno? I've heard (many times) that an engine would run around a point leaner on the street than on a dyno jet. Therefore, to achieve a 11.5:1 A/F ratio, should one tune their car to 10.5:1?

Can anyone confirm this?

I do A/F tuning in 5th gear to make it a more real-worlrd engine load.... and tune for low 11's (i.e. between 11 and 11.5) rather than exactly 11.5, figuring that it might go slightly leaner on the street.

Andi

 

[Guest]

Thank Peter/Andi.

 

[supra400hptt]

One pump can pull 22 amps I believe. I'd adjust the fuse accordingly. 60 amp unless you can find a 50.

 

[Guest]

supra400hptt-

22A? Wow, more than I thought. Maybe I'll put in a 50 amp fuse then. I rigged it up with a 30A fuse temporily so I could finish dynoing and everything seemed fine. I think I got some water in the last fuse holder which is probably why it overheated. Thanks for the info. I'm going to post some videos of my dyno runs on our site, in case anyone is interested. Not like it's anything special. BTW, I just posted some new pics of our single-turbo kit on our site; I know some people were eagerly awaiting them.

Paul
http://www.directedengineering.com

 

[Boost Junkie]

What size relay do you have? IMO, a single 30 or 40 amp is marginal at best. You can wire two 30s in parallel, or buy a single 80-amp relay. BTW, 80s are hard to find.

Get a built-in wideband and you won't have to guess about the AFR variation from boost pressure to boost pressure, or dyno to street, or day to day.

Steve - FJO dealer

 

[dre99gsx]

wideband

speaking of wideband, FJO unit is something I would highly consider. I've had it on my DSM for afew weeks now, and its doing a great job, even on a daily usage (city driving, etc). I am dynoing this sunday to do a comparison with the shop wideband, and some tuning. Very optimistic, and its probably something I would get, along with the egt gauge for precise tuning at your fingertips.