Thread: Questions reguarding my turbo setup and AF mixture

Hey guys, I am currently running a USDM DE, T25 @ stock boost (7-8psi), JWT ecu, 370cc injectors @3bar, S4 cams, stock maf, and 3inch turbo back. I do have a vacuum leak. My vacuum at idle reads around 10 in hg. Is my stock maf causing my lean mixtures, should upgrade to a E60 maf, JWT reflash, with 370cc @ 4 bar?

I am getting a 12.4-12.5 AFR on my wideband @ WOT. I would like my AFR to be around 11.8@WOT. Heres a picture of my #4 spark plug

you should be finding that vac leak before doing anything else

you will get lower vac with s4 cams

check for boost leaks

if your jwt ecu is setup for your setup no need to change it stock maf will be maxed out really quick

need to know how old are the plugs what the others look like

you cant decide what you want your afr to be with a jwt only they can hence why they are obsolete now and replaced by much better options

Ive sprayed carb cleaner all around my motor and no change in idle. This vac leak has been a pita. I'm starting to believe its my charcoal canister. Yes, my jwt is tuned for my exact setup. Im afraid Ive maxed out the maf.

try using brake cleaner and not the cheap walmart stuff the legit brakeklen brand

also like i said vac will be lower on the s4 cams

there are not that many places for there to be vac leaks on these motors and most of them are very easy to change the hoses which i recommend to all owners of these older cars.

do you have any vac tees? they are prone to break and leak

Just bump your fuel
Pressure 1-2psi and see your wot afr

At stock idle with s4 cams you will have very low vacuum. I had to increase my idle and mess with the fuel map to get my vacuum around 12-15. How do you know you have a vacuum leak? I highly recommend getting a tunable ecu and getting your car dyno tuned. And you probably are very close to maxing out your maf. One of the best investments would be a nismotronic and a map conversion. Those pesky boost leaks wreak havoc on maf systems.