stock injectors okay with stock turbo at 12psi?

[1988montecarloss]

planning on getting an enthalpy rom tune done on my car (S13 with sr20det) and pushing the stock turbo up to 12psi instead of the stock 7psi, are the stock injectors (370cc) enough for this?

motor is basically stock other than 9:1 forged internals, a FMIC and the BOV is vented to the atmosphere

[Ilya]

on a B-18 Motor that you have, you will be just fine

[TheRealSy90]

Stock boost is not 7psi. 7psi is the factory wastegate pressure. The stock boost with the oem boost control solenoid connected properly tapers between 11-12psi depending on load and rpm. I ran my bone stock redtop on 12psi for 3 years with only a walbro 255, and i'm still running that same engine now 6 years later. 12psi is the generally accepted safe limit on the t25 before you're just "pushing hot air".

HOWEVER, due to you having higher than stock compression now, i'm not sure if the stock 370cc injectors will be enough. But your contact at Enthalpy will definitely know, and they should recommend a bigger injector size if you need to upgrade them. If you really want to stay with stock injectors, you could raise the fuel pressure to effectively force them to have a higher capacity, but of course you would want to coordinate this all with your ROM tuner so that you are on the same page.

As an aside, I recommend recirculating the bov as well. But if you really need to vent it they can adjust the rom to compensate.

[Sleepiedaze]

youll be fine.

[1988montecarloss]

Stock boost is not 7psi. 7psi is the factory wastegate pressure. The stock boost with the oem boost control solenoid connected properly tapers between 11-12psi depending on load and rpm. I ran my bone stock redtop on 12psi for 3 years with only a walbro 255, and i'm still running that same engine now 6 years later. 12psi is the generally accepted safe limit on the t25 before you're just "pushing hot air".

HOWEVER, due to you having higher than stock compression now, i'm not sure if the stock 370cc injectors will be enough. But your contact at Enthalpy will definitely know, and they should recommend a bigger injector size if you need to upgrade them. If you really want to stay with stock injectors, you could raise the fuel pressure to effectively force them to have a higher capacity, but of course you would want to coordinate this all with your ROM tuner so that you are on the same page.

As an aside, I recommend recirculating the bov as well. But if you really need to vent it they can adjust the rom to compensate.

what is stock compression? i was told they internals were stock compression ratio and i always thought it was 9.0:1 :confused:

im pretty sure my car doesnt have the factory boost solenoid on it either and i planned on using an electronic boost controller i have to get it to 12psi, but how would i tell?

sorry for all the noob questions, this is my first sr20 :ugh:

[KAT-PWR]

Stock for sr is 8.5:1 IIRC

[blackmags91]

Don't forget about your MAF. The factory sr20 maf starts to top out around 12 or 13psi right? (someone please correct me if im wrong)
If you're already getting a ROM tune, throw a z32 MAF on there and never worry about your maf again.

But like everyone else has said, make sure it doesn't go over 12psi and youll be fine. I daily'd and tracked a completely stock redtop at 11-12psi for about 3 years before upgrading maybe 2 years ago. Motor is still going strong after all of that.

[TheRealSy90]

99% of the time they boost solenoid isn't included with imported swaps, so you most likely don't have it. If you did it would be plumbed in the vacuum line between the wastegate actuator and the pressure source. A manual controller set at 12psi will work perfectly as that's what I always used.

Also, the stock mafs will work perfectly at 12psi.

[1988montecarloss]

Stock for sr is 8.5:1 IIRC

alright im assuming thats what it will be but i will compression test it too, 8.5:1 should result in 150-160psi correct?


Don't forget about your MAF. The factory sr20 maf starts to top out around 12 or 13psi right? (someone please correct me if im wrong)
If you're already getting a ROM tune, throw a z32 MAF on there and never worry about your maf again.

But like everyone else has said, make sure it doesn't go over 12psi and youll be fine. I daily'd and tracked a completely stock redtop at 11-12psi for about 3 years before upgrading maybe 2 years ago. Motor is still going strong after all of that.

i already picked up a z32 maf, probably shouldve included that in my first post haha

99% of the time they boost solenoid isn't included with imported swaps, so you most likely don't have it. If you did it would be plumbed in the vacuum line between the wastegate actuator and the pressure source. A manual controller set at 12psi will work perfectly as that's what I always used.

Also, the stock mafs will work perfectly at 12psi.

yeah im %99.9 sure mine doesnt have one although ill go double check

thanks for the advice guys :)

[KAT-PWR]

You said you are 9.0:1 compression but yes that range will probably be okay
Do a boost leak test prior to running on the new tune just because

[UG-T]

Don't forget about your MAF. The factory sr20 maf starts to top out around 12 or 13psi right? (someone please correct me if im wrong)


Stock SR runs 11-12psi on the stock t25 and factory MAF... Factory MAF will measure anything the t25 can flow.

I ran mine (stock injectors, stock maf and stock fpr) @ 16psi spiking 18 for 3 years on fl 93 octane. Only mods at the time. 255lph fp, evo 9 front mount, hks hi power and HkS induction kit.

[!Zar!]

12psi is totally safe. You need nothing else.

Though I hope you have an upgraded fuelpump and clean fuel filter.

[UG-T]

To OP, if that's all you have done and not much else planned... stock MAF and factory tune is quite fine

[1988montecarloss]

12psi is totally safe. You need nothing else.

Though I hope you have an upgraded fuelpump and clean fuel filter.

car has a walbro 255 and will get a new fuel filter after all this is done

[TheRealSy90]

You don't even need to have a tuned ecu if you are t25 on 12psi with stock mafs. Oem ecu will work perfectly.

[!Zar!]

car has a walbro 255 and will get a new fuel filter after all this is done

Then you sir, are set to go.

[bmaddock]

For future reference, you can make some assumptions from other people's numbers and use http://www.deatschwerks.com/resources/fuel-calculators/fuel-injector-calculator