Hi Guys,

What is the max power you can get out of standard fuel system and injectors.

Cheers

 

Comfortably, around 350rwhp.

 

My friend is maxing out his stock injectors (98%) at 300 rwhp on the dyno.

Mild street port
PFC
High flow cat
Blitz SMIC
And the rest of the bolt on's

 

Bad tune.

 

Tuned by Steve Kan.

 

Some people run these cars way to rich. However, 350 is really pushing it. In my opinion 320 is pretty much the safe limit.

 

Sorry to ask but what do u guys put in the "bolt-ons"??
Would like to be sure I'm not forgetting an element.

 

I think there is a difference in a dyno runs verse running the car all the time at the higher power levels. I know several people who have dyno'd cars using the Pettit ECU (so stock injectors) for 340-360rwhp depending on the porting of their engines. Now, they didn't run those levels 24/7, but they did run those levels at the drag strip (one of them running a 11.77 pass). Those cars were also road raced fairly heavily, but once again, not at those levels. IMO, it's about using it wisely.

I'm not suggesting everyone go out and do it, but it most certainly can be done and has been for years.

 

Its also possible that the dyno (where the Steve Kan tune was done) was reading low. Even if that is the case, you still can't run 350 rwhp on stock injectors "comfortably".

 

Been done. You guys can call it rubbish if you like, but it's been done before...

https://www.rx7club.com/showpost.php...4&postcount=25

 

I ran 353hp comfortably for a year 1/2. Then car overheated, which lead me to where i'm at now =)

 

Has the fuel pump been rewired?

And I agree about a stingy dyno.

 

I think he has a supra pump. I'm not 100% on that.

 

+1, been done by many people

I didn't always feel 'comfortable' running 14 psi on the stock fuel system, but I always had the wideband hooked up and everything was fine. I am sure my injector duty cycles were close to 100%, lol (couldn't datalog them... only an rx7.com chipped ECU). 90% of the time I drove around on 10psi.

BTW, at 10psi I put down 300whp uncorrected on a humid 95 degree day. No fan either, lol. I am sure that on a standard day with 14psi I was around 350whp.

 

here is a fuel calculator to try different injector sizes to guesstimate the amount of power potential. http://rx7.com/cgi-local/3rdgencalc.cgi
According to that calculator the stock injectors are good for 338 FLYWHEEL HP @ 80% duty. Course i don't know how accurate that calculator is.

Increased fuel pressure from an aftermarket FPR could allow for more HP, and old/dirty injectors that don't flow like they used to will run less HP. It's all relative to what setup you're running, and how lean you're tuning. Shoot you could run a wet nitrous system and get another 75 hp without using a drop more fuel from the injectors.

 

I worked out the basic numbers a while ago. See this post.

 

I'm not comfortable with 100% injector duty. I don't think many people are.

 

For fairly cheap you can get a set of used stock 850's, have them cleaned, and a stock primary rail, have the rail milled (there is someone on the forum that does it for 10 dollars) and upgrade your primary's to 850's and then comfortably be able to make 350+ WHP without passing 85% DC. You could probably do all this for around 100 dollars.

 

those hp claims on stock turbos were done on 93-94 octane fuel. 91 octane Ca gas is totally different. 300-320rwhp is very typical for stock turbo/fuel system in CA.

I made 403rwhp@14.5psi on stock injectors back in 97 with the PFS gold box. Injectors were maxed out at 6500rpm and A/f was still within safe margin. However, VE, atomization and AIT comes into play in this senerio.

I remembered losing hp by putting the 1600cc injectors in place of the 850 due to poorer atomization (20rwhp). It all depends on the entire system and what it likes.

Calculations and simulations are just that, it predicts what it should/capable of doing. Real life suituation is what counts.

 

Holy crap!

 

The problem with that is you lose a bunch of your power band when you can't go past 6500 rpm. 403 rwhp is a big number, just not for very long

 

Keep in mind the stock injs are side feed and thus are kept cool by the gasoline flowing through them. Higher IDCs with side feeds is 'safer' than top feeds.

 

Recently, I read a post that pointed to an online calculator that gave resulting fuel flow and horsepower based on injector size, fuel pressure, duty cycle etc... I can't find it now. If anyone knows where it was, it was very informative.

 

Sure it didn't have anything to do with the high imp injector controller used with resistors and low imp injectors?

There have been a few posts latley about gains by swapping to the FJO peak and hold driver.

 

check out www.rx7.com, more specifically http://rx7.com/cgi-local/3rdgencalc.cgi