Injector Advice and supporting mods

[Slizz]

In a nut shell my car got a fuel leak, pulled the plenum cause it was the fuel line in between each fuel rail, decided to test injectors, shat my pants.

I'm trying to decide whether I should go with 615cc or 740cc injectors. Here's a list of mods I'm gonna get before I get injectors:

Stillen Intake with velocity stack (already have oncar)
ECU Tune
EFI Wiring Harness
PTU Harness w/ sensor
Alt-Trans Harness
Knock Sensor Relocate
Boost Gauge
CZP Boost jets for 11-13 psi
3" dps
3"TP
z1 motorsports 3" Pg coupe exhaust (I want fuggin loud azz car!)
Short Throw Shifter
brake master cyl. brace

My car is 92 tt 5sp 151k miles maintenance is pretty much up to date t belt done 40k ago, need to check timing and run boost leak cheak but I will do that once I get it running again. My Ultimate goal is 600 whp but I will build the engine before I shoot for that #, I'd like to hit about 450 whp for now but thats gonna take me awhile to get everything for it.

Basically I wanna know if the 740cc will be too much, and if my clutch will slip at 11ish psi (11 or 12 is all I want) with the above mods. I plan on doing full 2.5 ash spec piping, z1 b.a smic, doolz intake, full ur pulley set, clutch & flywheel, and a few other misc things. But that will be after I get it up and running, over time thats all the stuff I want to get done....

Any help would be much appreciated I need to decide by friday cause thats when i'm sending my ecu out.

Thanks boysss!!

[Slizz]

Anyone???!?

[Slizz]

nvm im just gonna go with 370cc until i can afford to do all bolt ons... then ill do motor build/turbos and bigger injectors.

[ThisIsSparTTa]

Injectors by themselves don't increase power. You'd see the same power on 615CC or 740CC. My understanding is it's better to go with 740CC because there have been more tunes done with them, so the base tunes are more reliable. I'm not really aware of any benefit of the 615CC over 740CC. With your mods, I doubt you'd hit the limits of the 615 or 740CC.

[Slizz]

I'm more worried about slipping clutch, and dangerous intake temps because of running stock ic piping/ic's, I dont want to blow it up but I cant afford to put a clutch/ic's in it unless i want to wait until next winter hahaha. So i'm just gonna play it safe and go with 370's until I'm 100% certain everything will be able to hold the next level... I guess.... I wanted to do 740's so I'd never have to change them again, but at this point i don't care about that specific part i just want to drive it owned it for like 6 months now and driven it literally 1 month.


SO basically gonna run 370's until all bolt on's. Then get new wheels/tires, body work n paint then, some interior work and simple sound system, suspension and brakes. Then I'll work on getting turbos, 740's, full engine build top to bottom. Then I'll pull engine/trans and work em ;P

[ThisIsSparTTa]

Again, larger injectors don't mean more power. They still provide the same amount of fuel on the low end. They give you the ability to feed more fuel on the high end when the engine really needs it.

[Slizz]

I never once asked what injectors do. I know what they do, but if I'm getting it tuned for 715cc injectors over 370cc injectors obviously its gonna do something different rofl.

[ThisIsSparTTa]

No, it won't.

If you had a SZ base tune for 370CC, upgraded to 740CC without changing a single other thing, and then used a SZ base tune for 740CC, your car would run the same.

[Slizz]

So basically your saying I could run 2200cc injectors and nothing else at all? AND NOTHING WOULD CHANGEE? Yea... It dont compute... thats double the flow rate, if the ecu knows theirs 740cc injectors in there then it knows thats how much they feed so obviously they are going to feed more fuel if they change the fuel maps... Not making sense to me at all.

[zcar93na]

A base tune for certain size injectors is so the ecu knows what size injectors are being used. They're all different resistance so the same signal is gonna make them do different things. So yes, you could have 2200cc injectors on a completely stock car with a base tune. Because the ecu is reading off the o2 sensor to get the right air/fuel ratio, and your tps (throttle position sensor) and whatever it is that monitors boost as to how much fuel you need at that particular moment. I have a non-turbo, so I'm not TT savvy. But I have common sense.

There, does it compute for you now? You obviously wanted advice when you posted this, then you argue with someone that's trying to help you, steer you in the right direction? That's not how it works.

[Slizz]

Sorry, just frustrated, I wasn't really thinking honestly... Thanks guys, I'm gonna go with 740cc then! Sorry sparta, I read somewhere that higher injectors with no real big power boosters can actually decrease performance, but if what you guys say is true I'll trust ya.

Thanks

[zcar93na]

With everything you listed you want to get, 740's will be great. If you want to get those now and a base tune to go along with them, that's fine. But as you get more bolt ons (turbos, exhaust, etc) you'll need to get a new base tune eprom chip to suit those modifications. The first ecu tune will be the most expensive, after that you just give them (z1, sz, czp) specs and they'll program a chip that you can install. Shouldn't be anymore than $100 each.

Also, buy your parts that are close in relation as location at the same time; Like you can do your clutch and DP's at the same time, etc.

[Slizz]

I have ebay dp's and test pipes intalled now, they were a pain to install but they work their only 2.25" tho so I want to go up, might just run dumped test pipes till i can afford full exhaust, clutch/flywheel, rear main seal, throwout bearing ect ect

[Slizz]

Hopefully gonna have my ecu sent out tomorrow morning to ash for 740's woohooo