do i need to step up to 440 injectors

[lncatch]

im going to upgrade my turbo to a gt28rs, i am only going to run 7-8 lbs of boost, i have an afc, fmic, turbo back exhaust and the 626 intake manifold. Im just wondering if i need to step up to 440 injectors. Everything else runs fine with the stock injectors, im just not sure if they can handle putting out what the gt28rs will need. if anyone can let me know that would be a great help thnaks

 

[SeR_Cyclops]

I say at that low PSI you will be fine on the stock injectors.

 

[climb1019]

i have a gt2860 running about 12 psi, lowest it will go (bang), with fmic, exhaust unichip, and it runs about 13 afr at high rpm, so if you find a good deal go for it to keep safe.

 

[HondaEat-R]

Remember, PSI is not as relevant as CFM. You can run a larger than stock turbo, and maintain the same "psi", but the CFM has surely changed, and is going unmeasured. PSI is simply pressure, CFM is actually a volumetric flow rate. If you have a way to tune them, get them. It's a cheap upgrade that insures a more relaxed duty cycle, and gives more room to grow. And, BTW, I have a set on 440's sitting here, but one was stuck open and leaky. You may be able to clean them & use. Let me know. Good luck.

 

[yudkib]

psi is more related than you think. pick any two turbos and pick any engine. that engine has a maximum volumetric consumption rate for a certain psi and rpm, and both of those turbos have maximum volumetric flow rates for the same psi. if the turbo flow rate is greater than the engine flow rate, then its still running efficiently. so both turbos could run 10psi at 5000RPM and be identical. but if the max flow rate for the engine (at a given PSI and RPM) is greater than the turbo flow rate, boost drops off.
so both performed identically at 5000 RPM- but at 6000 RPM the gt2554 cant keep up, however, the max flow rate on the gt2860 is still above the maximum for the engine. so its still 10psi at redline whereas the gt2554 drops to about 8, even though the wastegate hasnt changed. its a complicated process - but basically, boost builds in the plenum... if the turbo can pressurize it fully, then its always the same... the differences come where the turbo cant continue to pressurize it. and youll spend hours learning turbo maps to figure it out.

 

[43975]

What really important for you is what's going to pop your motor!!! Look at CFM ratings to know what the FS motor can and more importantly can't take.
Check this thread
http://www.mazdas247.com/forum/showthread.php?123715235-Need-some-larger-turbo-psi-skool-n
I basiacally came up with what limits you can run.
For the record I'm only running 4 psi on a GT28RS and I'm still on stock injectors. I evenually plan on tuning to run 6-7 (needed a Wideband first) but that is as far as I'm willing to go on stock motor.
Unless you have some way of tuning the 440's you don't have an option but to run stock.

 

[lncatch]

I have 440 injectors at the house that ive had for a while and I have the split second afc. As far as i know they are good, i got them from a buddy who upgraded his wrx injectors...from what i understand the wrx injectors are a drop in for the msp. I just figured if i didnt have to go through the hours of trying to tune the car then id just stick with the stock injectors

 

[43975]

If your dropping in a GT28RS and trying to run 7-8 PSI on an unforged motor, you HAD BETTER, spend those hours tuning your ride!!! You also need a wide band to tune it in properly. I would say drop in the GT28RS run low boost and see what your AFRs are running then take it from there. I know a couple guys that ran the GT28RS for a very long time unforged, stock injectors and stock ecu. I myself ran untuned with a MSP ecu for about a year and the car ran well. But I had no wide band so who knows how close I was to popping the motor.

 

[boostedprotege]

the stock injectors start to max out around 14-15psi on a gt2860rs... i use mpi piggyback to tune.... my afr's stick around 12.5, with meth 11.8

 

[boostedprotege]

If your dropping in a GT28RS and trying to run 7-8 PSI on an unforged motor, you HAD BETTER, spend those hours tuning your ride!!! You also need a wide band to tune it in properly. I would say drop in the GT28RS run low boost and see what your AFRs are running then take it from there. I know a couple guys that ran the GT28RS for a very long time unforged, stock injectors and stock ecu. I myself ran untuned with a MSP ecu for about a year and the car ran well. But I had no wide band so who knows how close I was to popping the motor.

at 9psi on the msp ecu you still runn pig rich 10.0afr's but your run into sparkcut.. expecially in cooler weather

 

[lncatch]

i have a wideband and the stuff i need to tune it, im not concerned with doing the tune, i jest need to have my car up and running. just seems like going off what i have now to tune would be much quicker than starting from scratch pretty much with the 440 injectors, i can always tear into that some other time when i dont have to have the car.so as long as its safe just running stock boost then ill just stick with the stock ones untill i have a chance to do the 440's

 

[boostedprotege]

the stock injectors are more then enough... i peak at 14psi n still on stock injectors but i'm prety much at the limit if i wana go higher i need injectors..