need advice on S3 fuel - SRT Forums

kornbred · 10-27-2009, 09:04 PM

I've pieced together a S3 kit, but I don't have the S3 fuel rail or fuel pump canister. I do have a walbro 255 with rewire, DW 650's, and a DSP. My problem is I've maxed out the injectors according to the duty cycle this formula gives PW*RPM/1200000. I'm boosting to 24 falling to 19 and the DC% is over 100% from 4000 - 6000 rpm's.

That said do I just need some 750's or should I get a rising rate FPR setup like the S3? I already have the S2 injectors if I go with the S3 setup.

lymanrok · 10-27-2009, 11:37 PM

from upto i know s3 fuel has been replaced with a new solid state double fuel. fuel works fine at first when driving the car but when car is pushed at 65-75 mph, the engine begins to slow and signs of fuel starvation are apparen.

duster360 · 10-27-2009, 11:44 PM

Quote: Originally Posted by kornbred

I've pieced together a S3 kit, but I don't have the S3 fuel rail or fuel pump canister. I do have a walbro 255 with rewire, DW 650's, and a DSP. My problem is I've maxed out the injectors according to the duty cycle this formula gives PW*RPM/1200000. I'm boosting to 24 falling to 19 and the DC% is over 100% from 4000 - 6000 rpm's.

That said do I just need some 750's or should I get a rising rate FPR setup like the S3? I already have the S2 injectors if I go with the S3 setup.

Did you have your injectors scaled in your PCM?
What does the A/F look like from 4k-6k?
Whats the EXACT pw PID you're logging?(post the log?)

650cc at 58psi is nearly the same fuel volume as S3 at 68psi(S3 higher reg)

kornbred · 10-28-2009, 10:19 AM

the tune I'm running was rescaled for the S2 injectors I had on my previous setup, I just pulled some fuel when I put in the 650's on the e1 I had. With the S3 turbo my WOT fuel is set close to 0 with the hand held.

AFR is up and down from 12.0 at 4k to 11.2 at 6k, I haven't smoothed it out yet.

AVG TOTAL WORKING PW is the PID I'm working with. I'll post a log later when I get home.

duster360 · 10-28-2009, 11:05 AM

Quote: Originally Posted by kornbred

the tune I'm running was rescaled for the S2 injectors I had on my previous setup, I just pulled some fuel when I put in the 650's on the e1 I had. With the S3 turbo my WOT fuel is set close to 0 with the hand held.

AFR is up and down from 12.0 at 4k to 11.2 at 6k, I haven't smoothed it out yet.

AVG TOTAL WORKING PW is the PID I'm working with. I'll post a log later when I get home.

What PCM are you using?
If its not a S2/S3 PCM, is the PCM scaled for 3bar sensors?

kornbred · 10-28-2009, 12:29 PM

It's the stock PCM but it is rescaled for the sensors.

SilvrMike · 10-28-2009, 01:40 PM

my .02

spend 150 on a rail , and 75 on the fpr , put it on, and watch it run with out a problem and sell the other stuff

bye bye headaches , hello driving

kornbred · 10-28-2009, 09:16 PM

I'll try to post a log tomorrow. I didn't have time to find a host tonight.

kornbred · 10-29-2009, 09:39 PM

S3_10-29-09.log
Finally got it posted. You'll probably have to turn off your firewall and allow pop ups, at least I did to post it. Seeing some knock now too that wasn't there with the e1, AFR is < 11 from 5~6k.

duster360 · 10-30-2009, 08:23 AM

Quote: Originally Posted by kornbred

AFR is < 11 from 5~6k.

Notes:

1) Boost control sucks. Its pulsating +/- 6psi at WOT past 4500rpm. Looks like your Off PCM boost control becuase you can see the WG duty cycle is trying to correct it but not having much luck at it. Or you're on PCM Boost and someone really screwed it up?

FYI:The PCM will inject extra(uneeded) fuel for sudden rises in MAP.

2) You said A/F on this run is LESS than 11.0, as in 10.9 and lower. But you previously mentioned "12.0 at 4k to 11.2 at 6k". Thats a pretty big shift rich. (see#3)

3) Open loop FA is the A/F the PCM is trying to hit. For one thing your's is all over the map at WOT and just ugly. There's a goffy lean spike right after WOT but then its tanks to under 10.0:1 from 4800-6000rpm. Most likely COT is causing that put the OLFA looks so crappy its hard to say. Logging EGT will tell you for sure. If EGT is over ~1740F right when OLFA drops rich,,thats COT(cat over temp enrichment)

So YEAH if the PCM is trying to hit an UBER rich A/F(9.8:1) your DC% is going to be pretty high. Add in the wild boost swings and a little extra fuel the PCM will add for this,,and you get a DC over 100%.

FYI the PCM caps MAX IPW at around 90-92% so IF at your max DC, your true A/F is in the 10s, you have no fuel issues.

Imo you need some serious tuning(boost, OPFA) help before you waste money on any new hard parts.

kornbred · 10-30-2009, 09:11 PM

this is the tune I referred to in the first posts s3_2.log, guess I loaded the wrong one.
The other one is after I unhooked the battery and zeroed out boost control with the hand held. I am going to get in touch with the guy that tuned it and get him to make some adjustments.
You think the inj's will be fine?