Ideal AFRs? Rich after injector change.

[Fidhle007]

So now that I've gone wideband I'm curious about my AFRs. I'm running a TMS chip for Euro MAF and 24# injectors but I had 21.5# S52 injectors installed for awhile (NEVER trust ANYTHING you read on the internet.) Despite the undersized injectors everything seemed pretty ok (between 15.1 and 14.5 at idle and cruise and going up to the mid 12s under load) but last night I switched to Bosch Design IIIs (PROPERLY SIZED) and it's running rich (low 12s at idle, up to 10ish under load.) I know I have to give everything a chance to remap but is it bad to run an S50 on the rich side? Also, I figure unplugging the ECU for a bit could help everything reset, should I go ahead and do that or let everything work itself out normally?

Thanks!
Brendan

[e30polak]

My s52 ran rich for over 2 yrs because of the 24# injectors. There is no need for bigger injectors without cams unfortunately. Once I got my car custom tuned it ran much better than with the TMS tune.

[Dillinger]

(never trust anything you read on the internet.)

qft

[loonibab325i]

24# injectors seems to me like an overkill, no?

I would stick with the s52 injectors... I'm running the TMS cam kit with the 24 # injectors and the car even seems to run a bit rich straight of that setup.

[jackbenny]

Out of curiosity (and not trying to threadjack here) but what size injectors are most people running if they have the Euro/540 HFM and no schrick/sunbelts? I'm prepping my motor for the swap and I have the HFM and planned to get 24lb injectors coupled with a chip from Matt and TRM. Eventually I would like cams but just want to get the swap running and all the teething problems sorted. Is it better/more cost effective/smarter to just run 21.5lb injectors and wait until the cam swap to upgrade injectors and software?

[shopkeep]

How about getting an SAFC and try leaning it out a little? Just a thought...i have been wanting to get a wideband + SAFC and see how much more i can squeeze out of mine...I have 24# injectors as well and this thread makes me want to get them even more now. I know that is the cheesy way out, just an idea though.

[Fidhle007]

Well I pulled out the ECU and let it sit on my desk since lunch so maybe it will have a better chance to remap now... It seems to run better with the Design IIIs than it did with the 21.5lbers but like I said, my AFRs are not where I think they should be. I'll plug it back in and report back when I know more.

Just FYI, the Design IIIs are what Turner sells in they're Stage II (or is it III) kit, which is essentially what I'm using: Chip, Euro MAF, 24#, intake, flywheel. Maybe the secret to good AFRs is to run pink tops with a TMS 24# tune...? I'm planning on more power mods in the near future anyway so eventually I'll need the design IIIs...

[z31maniac]

Out of curiosity (and not trying to threadjack here) but what size injectors are most people running if they have the Euro/540 HFM and no schrick/sunbelts? I'm prepping my motor for the swap and I have the HFM and planned to get 24lb injectors coupled with a chip from Matt and TRM. Eventually I would like cams but just want to get the swap running and all the teething problems sorted. Is it better/more cost effective/smarter to just run 21.5lb injectors and wait until the cam swap to upgrade injectors and software?

matt will tell you the 21.5s are good even for Schricks.

I'm going to run the pink tops, TRM chip, 540 MAF.

[z31maniac]

Oh and my dead hooker stacking compatriot, I'd still like to see 13:1 under load, not ~12.5:1.

[jackbenny]

matt will tell you the 21.5s are good even for Schricks.

I'm going to run the pink tops, TRM chip, 540 MAF.

That's good news. Now to verify I have 21.5 lb injectors since i can't believe everything I read on the internet! ;)

[Fidhle007]

Oh and my dead hooker stacking compatriot, I'd still like to see 13:1 under load, not ~12.5:1.

I'm seeing 11 to 10 under load but it seems to be better now that I've unplugged the ECU. I'll give it a tank or two to level out and then I'll see where it's at. Maybe the pink tops are the holy grail after all and I got lucky..

[z31maniac]

Yikes that's rich even for FI!

[e30polak]

Yikes that's rich even for FI!

Word. You could run a dry-shot of NOS and be ok with those numbers lol.

BTW I have the TMS tune for the same mods and the AFRs suck. That's your main culprit, you'll see that when you put it on the dyno.

[matt]

Unplugging the OBD1 ECU for even a half a second will clear its adaptations.

21.5s are fine up to 250whp. As long as your chip is programmed to match them.

[Fidhle007]

That's the thing, it's a TMS chip for 24lbers and Euro MAF...? So in theory I should have been running lean with the 21.5s and now things should be right but that doesn't seem to be the case...