I'm interested in the larger volume injectors that are sold by M7 and others and at what point they become necessary. I have several performance improvements (see below) and am wondering if there would be an improvement in performance with an upgrade to the 400 injectors since I understand JCW comes stock with 380 injectors.

Thanks for your help.

 

I'be got the dual spray Bosch (380's) from Helix and they work great on my setup

 

On the side that says get larger injectors:
I've logged data that shows the ECU thinks the injectors are open all the time at red-line. Some of the tuners say that the cars need them for a 19% pulley or mods that improve airflow to that type of degree.

Arguements against: Some of the modders have gone to very high power levels on stock injectors with A/F ratios that are fine.

What it comes down to is that if you only have the "begginer" mods, don't spend the $. But if you're going well beyond the basics, use diagnostics to let you know if you need them (look at your injector duty cycle and A/F ratios to know for sure).

Matt

 

Most A/F graphs I have seen show the mini pig rich, even with CAI,17%,Headers,exhaust,larger i/c....on stock injectors.

 

with my mods, I noticed a strange flat spot when I fitted my Milteck cat back, low and mid have improve a lot while high wasn't that good, then I fiteed M7 400CC and power on high revs was back

 

Dr:

Yes but: It turns out that, especially with smaller pulleys, more power is saved at the top end by cooling the pistons with more fuel, so you get better peak power output with a fuel level that is not acheiveable with the stock 330s. The 330s give you safe AFRs, but the best power is from the big boys (if tuned properly).

BTW we have a smokin' deal on JCW injectors right now: $295 for a set of 4.

 

get to have all the fun!

Matt

 

pberry51mini,
How about 540CC's? These fit the stock everything, no spacers, no plugs needed, just tools to install them! But they will be a bit too big.

To use these you would need to retune the ECU by removing alot of fuel. The problem when you do this with piggy backs ECUs, is that you will increase timing (because of how they work) which can cause other issues. At this point there isn't really any ECUs that you can change timing with.

For the mods you have i would stick with the 380 injectors, they are best matched for your car.

 

Not "yes but":

Richer AFR than "max torque" AFR will give less power, at the benefit of increased detonation resistance through cooler combustion temps. On pump gas, tuning any leaner than 12.5:1 on a boosted engine is a recipe for ka-blam-o. It doesn't matter what injectors you have as long as you can tune for the AFR you want, disregarding duty cycle.

Remember, 12.8 to 13.2:1 is "max torque" on most gas engines, however you want to run at least a number richer [i.e. 11.8 to 12.2:1] on a boosted engine to cool combustion and reduce knock. Also remember that 10% Ethanol gas that most of us run effectively increases AFR by 0.5:1, meaning that if we tune for a 11.5:1 lambda, the real AFR is actually 12.0:1. The big power turbo cars [like STI's and Skyline's and Supra's and Evo's] run as rich as 10.5:1 to reduce knocking. They could lean it out to make more power but it wouldn't last long.

So in the end Eric, you're not "saving power" by adding fuel, you're saving the engine by not knocking.

 

You guys are the best.
Ryephile - man you have really studied this stuff - I really appreciate the input you and Dr. O have put into this. Thanks.

I've read the past threads on this subject and there doesn't seem to be any clear direction for me to go with my JCW so I'm going to just keep my stock 380s for the time being.

I hope this subject continues, I'm learning alot here.

 

I was speeking to Randy at Webb about this a few weeks ago when I ordered my pulley. He told me with my mods (15%, 2% header, exhaust, intake and such) it was not necessary and I belive but don't quote me on this i think he said they were running stock injectors on the mule and it ran a nice AF ratio. I'm not sure if that was pre or post twin charge though.


Seann

 

You're very welcome! Pushing the envelope forces you to learn one way or another. If you have the JCW 380cc's I'd venture to say you're fine on injector with average bolt-on's. Only if you chose to do twincharge or nitrous and the like will you need to worry yourself with bigger injectors.

--->safia: I can't say for sure what Randy is running, though I'd hope he's running at least 440's with his turbokompressor if he's running the ~22psi that Helix tunes the e-boost for. That all said, with your currrent mods you'll be fine with the stock injectors, but if you start doing headwork and a camshaft then consider JCW injectors with an ECU flash to match. That's the most important advice I can offer actually; to have your ECU flash match your injector size!

Cheers,
Ryan

 

Fair enough, I should have chosen my words more carefully

 

Like I said I don't know for sure what he said...just mentioned he was running stock up until...

I was gonna check out the M7 injectors