how come so many people use diffrent injector sizes for the same whp goal? I don't mean a small difference in cc but ive read multiple people using like 700-1000cc injectors for 400whp. I just wanted to know what the reason was for going that high unless they wanted to upgrade. i thought i read that too big of injectors wont atomize the fuel properly and that you should be within a certain "range" for your goal to have proper atomization and flow? whats size injectors for 350-400 whp?

 

Price was my main reasoning, I got a set of quality 1000cc injectors for a very good price and it left me room to step up, 350-400 may sound like oh I will be happy/have enough, but the truth is you will never be happy or have enough, hopefully I'll stop at 700 as I don't feel like upgrading any other supporting mods to get there other than the turbo and a second pump ;p

 

im looking to run it on pump gas. 93 so Im limited. i dont want to pay to play when it comes to fuel. I have reasons for 350-400. For me, Im not looking to do highway runs or drag all the time. i figured it would be a fun street car for my days off that could take something if needed that wasn't highly modded. you know, something to embarrass the rich guys driving their "sport cars" they bought off the lot. just all round fun to drive. I stopped hanging around all the people who build cars around here so Im not into the biggest dick competition anymore either. would be sweet tho if you did a 700hp ka. Think a guy in bradenton has a 850hp 240....or maybe it was a sti. I forget.

 

Usually its room to grow based. I bought 850cc because I don't plan on staying at 400hp. I'd like to see 500ish, but in time. The larger the injector the harder it is to get a stable idle. Sard injectors are a better design than the Nismo/Tomei units FYI. Larger winding and better spray pattern. That is if you are using the stock rail/intake manifold.

 

There are more things that go into "better injector than xxx" than spray pattern and winding size. More importantly minimum stable duty cycle, linearity, and void time. Dig up the Mazworx blog post on that sometime. The difference between big Bosch injectors and the Injector Dynamics data is ludicrous. Not to mention that I've never even seen similar data for Denso (PE, Sard) or JECS (Nismo, Tomei) injectors.

For "350-400whp" cars, use something in the 740cc range. 550's will run out somewhere just past 350whp, even though internet hardasses say that their buddy makes 4 million on 550's. Going larger than 740cc is where people start to have idle issues (depending on car and tuning). 850cc Sards idle well from what I hear. The 96# (1000cc) Bosch injectors have a questionable idle. Also, I'm not hearing good things about the RC 750cc high impedance injectors overall.

Just buy Nismo/Tomei 740's and be done.

 

I know there's more that goes into it, but not everyone is a "geek" if you will. But winding size does play a big role in the stability and response of the pintle. I believe Sards lag time is .85ms where the Tomei/Nismo is slightly higher.

I have 850cc Sards and my car idles rock solid. Thanks for the additional information Ep.

 

good information. you stated that intake manifold will effect it. I'm going to be using a gato manifold probably 8 injector one, maybe nitrous option later if I want to go past 400 without exceeding my turbos ability. excessive would be alright if they had a straight runner option but I'm not down for there cut and weld of the stock runners onto another plenum.....

 

was with you til here, now it just seems dumb.

 

So reasonably, no real reason to go with anything larger if someone were sticking to a GT2860RS "28R style" correct ?

 

Yeah, the 28RS should run out of breath before 550's run out of fuel. Duty cycle should remain reasonable as well.