Whats a Safe PSI Limit for my setup?

[jmwenick]

Hey guys here's my setup:

t3/T04E .50AR/.63AR 57 trim Turbo370cc InjectorsWalbro 190 Fuel PumpAdjustable FPRStock MafJRC IntercoolerTurbonetics Evolution WastegateRFL BOV

What do you think is a safe PSI limit to run on this setup?

[S13FX]

Well Anything pretty much above 8psi, because the stock maf I believe only will work up until about 220rwhp. Just get your self a z32 maf. And with a good tune you can push around 300hp safely. But it also depends on how good of a condition your engine is in.

[jmwenick]

Another question I have is at what psi will I have to start retarding timing?

[lrb_2000]

5-6psi..

[KATwo40]

Nah, I'd say more like 7-8psi. Don't run anything less than about 8psi, because the turbo operates pretty far outside the peak efficiency range below that. Optimum efficiency begins around 10psi and heads up to around 18-20psi, if I'm not mistaken.

[nismofly]

the 370s and stock mafs will limit you to like 250 ish

i wouldnt advise setting it above 10, and lower would be better in case you get a slight creep or anything

[WDRacing]

Yeah, I ran quite a few times with no retard at 10 psi. I was running quite rich at the time though, about 11:1 or so. With a good 12.5:1 AFR I'd keep it at 8 psi until you buy the MSD BTM for timing retard or however you plan on dealing with timing.

WD

[jmwenick]

Okay, cool. Thanks for all the input guys, I think I'll go for 9 psi with a 11.5 AF Ratio. What do you guys think i'll have for Horsepower? Any Guesstimates?

[nismofly]

probably right around 240 - 250 at the rear wheels

im going with a 50 trim .63 a/r, so yours might be a tad higher, but spool a little slower

youll have to see, every cars different

[Edub1]

You have some miss-matched stuff there. 9LBS on that turbo will probably over shoot the 370cc injectors. You also have a lot of un-used turbo.

That turbo should be set up with 460-550cc injectors and a Z32 MAF. Stock A/F ratio should be fine but you'll want to pull 3-4 degrees (guestimate) of timing.

Really, with that turbo you need to get it up on a dyno and tune it.

[KATwo40]

You have some miss-matched stuff there. 9LBS on that turbo will probably over shoot the 370cc injectors. You also have a lot of un-used turbo.

That turbo should be set up with 460-550cc injectors and a Z32 MAF. Stock A/F ratio should be fine but you'll want to pull 3-4 degrees (guestimate) of timing.

Really, with that turbo you need to get it up on a dyno and tune it.

Yes, you REALLY SHOULD tune this critter with the wideband/datalogging OR on the dyno with their wideband. Like posted above, 12:1-12.5:1 should be sufficient, but I'd at least pull about 5* of base timing. It's not a fix-all, but it does help keep the detonation to a minimum. Also, remember to toss in some fresh plugs, one step colder and gapped at .030" to help keep the detonation to a minimum.

Every engine is different, so take this as you will, but I hit 8-9psi on my 370's and have plenty of fuel. In fact, I had to dial the SAFC2 back quite a bit in the high torque rpm range under full boost to redline. That was to achieve a 12.2:1 ratio, or around it.

I think the best thing you can do is begin with what you have, tune the setup on about 7psi and see how it goes. If you want to overboost from there, go for it in increments of no more than 2psi, to be safe. Make sure you're either on the dyno using their wideband, or have a wideband with datalogging in the car...preferrably with a co-tuner/driver to help you stay safe.

Get everything dialed in, then change something else. Maybe change the MAF. Keep the boost and injector size the same. Remember to change only one thing at a time, so if you have a problem, you'll know exactly where to begin.

Many times people buy lots of stuff, slap it all in there and then don't know what the problem is when the have one. They post questions like, "My car runs funny...I just installed SAFC2, 550's, Z32 MAF, Turbo kit, Electronic boost controller, etc....What's the cause?

It's quite frustrating to try to answer questions like this. It's an easily avoided situation.

[jmwenick]

ok, thanks for the info guys. I have another question for you. With my 370's, if the Safc is at 0% correction does that mean I'm dumping all 370cc of fuel? Cause I was tuning tonight for 9 psi, and I brought it to about -1% correction, and I got worried, cause I heard that injectors can lean out if you run them at 100% duty cycle too long. Also, how can I check the duty cycle anyway? Thanks for the help guys, keep it coming...

[Edub1]

I'm not an SAFCII owner but there should be a setting to change injector size. But like I said, 9 PSI on a T04E 57 trim is going to be way too much air for 370s. There are threads about injector size if you look. You want to run around 300HP with that turbo. This should use ~550cc injectors.

That turbo moves a lot of air - I wouldn't **** around.

[jmwenick]

Thanks, so far, while tuning I have been alright for my AFR's and Knock. But can Someone answer my questions above^. Thanks

[KATwo40]

Thanks, so far, while tuning I have been alright for my AFR's and Knock. But can Someone answer my questions above^. Thanks

With the 370's, you should be seeing correction on high throttle around -27% to begin your tuning. From there, use the peak/hold function on the SAFC2 display to view RPM, knock, MAF usage and whatever else. Make your boosted run and watch the wideband. The moment you see the AFR get outside your desired level (11.4-12.5:1 would be fine, I suppose), lift the throttle that instant. Look at the peak/hold display to see at what RPM you lifted. Adjust the high throttle correction factor accordingly at that RPM range. Repeat as needed.

I'd begin this process on about 7-8psi. Monitor the usage of the MAF. If you start reaching 90%, I'd stop there. You'll want room for changes in air density associated with changing atmospheric conditions and locations.

9psi is probably pushing the 370's to somewhere around 85-90% duty cycle, depending on your fuel pressure. 80% duty cycle is the industry standard for maximum.

[jmwenick]

awesome info thanks, now all I have to do is figure out how to use the peak hold function

[Edub1]

You might want to check out this post. 9lb on that turbo should be ~ 300HP.

zerothread?id=21932

[KATwo40]

You might want to check out this post. 9lb on that turbo should be ~ 300HP.

zerothread?id=21932

Looks more like about 250-260hp to me...right around the good 370cc range.

I took the liberty of mapping this compressor on the DOHC. Please, excuse the crooked line. My hand is not so steady with a mouse.

Also, on this map, PR=1.72 (about 9psi).

[Edub1]

At 250 HP the 370 injectors will be maxed out. But, it's your motor - do what you like.

[jmwenick]

yeah, I am definetly ordering some 550cc injectors from deatschwerks quick. Last night, we were tuning for 8 psi, fuel pressure raised to about 45 psi, and the injectors were nearly maxed. I don't like running on the edge of destruction, so injectors are def coming. Just wanted to fill you guys in. Thanks for the help

[KATwo40]

yeah, I am definetly ordering some 550cc injectors from deatschwerks quick. Last night, we were tuning for 8 psi, fuel pressure raised to about 45 psi, and the injectors were nearly maxed. I don't like running on the edge of destruction, so injectors are def coming. Just wanted to fill you guys in. Thanks for the help

Good choice.