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View Full Version : How much psi can 20% injector handle



turbocoupe
03-31-2006, 12:06 PM
Has anyone ever ran a good amount of boost with 20% injectors.

Subliminal
03-31-2006, 12:08 PM
I think it varies, somewhere around 18-20 PSI MAX, maybe little more, maybe little less.

turbomopar87
03-31-2006, 12:36 PM
I just took off my 20+'s so i can run bigger. I was running 27psi. I also didnt even know what my fuel pressure was, and didnt have and A/F guage yet, LOL
It was only about 1600 miles anyway


i guess that was bad?!?! lol.

turbovanmanČ
03-31-2006, 01:08 PM
Every combination is different. There is no SET limit, your setup dictates it. For the record, ran 22-24 psi at the track and 29 psi on the dyno running a stock TIII turbo on my van.

turbocoupe
03-31-2006, 01:36 PM
OH yes thats great cause my plane was to run between 14-18-20 psi depending on the day i feel lol thanks guys

SpoolinGLH
03-31-2006, 02:07 PM
My setup was maxed out at 19psi..Egt's were at 1550 (Forged Je's)..i had a srt4 IC,super60 turbo,Stock Head and intake....

Subliminal
03-31-2006, 02:20 PM
Every combination is different. There is no SET limit, your setup dictates it. For the record, ran 22-24 psi at the track and 29 psi on the dyno running a stock TIII turbo on my van.

Simon, shouldn't you mention the extra injectors you were running when you did this? :nod:

turbovanmanČ
03-31-2006, 03:03 PM
Simon, shouldn't you mention the extra injectors you were running when you did this? :nod:

Nope, wasn't using any. I used the cold starts with stock injectors and fuel pump. When I went to +20's, I also installed an AFPR and 255 fuel pump, :thumb:

Subliminal
03-31-2006, 03:12 PM
So, you're saying that you were running nothing but +20% injectors and ran 29 PSI. So, basically, since they only allow 20% more fuel than the stockers, you should be able to run 24 PSI w/o touching the fuel system. Man! I knew Chrysler was robbing us of all sorts of hp by limiting the boost to 10 psi less than the max of the fuel system!:banplease:

Marcus86GLHS
03-31-2006, 04:40 PM
you really must monitor the engine's egt and/or air-fuel ratios when screwing around with boost and fuel, dont guess, dont ask what other people have done, just stick a proper gauge in the car and be sure.

iTurbo
03-31-2006, 04:43 PM
I've run up to 21 psi on my Shelby Lancer for the past year. It's got 3" exhaust, +20s, AFPR (55psi base), adjustable zener, and a couple other minor things.

I've since turned the boost down to 12psi for driveability reasons. With the single grainger @ 20 psi, I was getting way too much part throttle boost.

turbovanmanČ
03-31-2006, 04:45 PM
So, you're saying that you were running nothing but +20% injectors and ran 29 PSI. So, basically, since they only allow 20% more fuel than the stockers, you should be able to run 24 PSI w/o touching the fuel system. Man! I knew Chrysler was robbing us of all sorts of hp by limiting the boost to 10 psi less than the max of the fuel system!:banplease:

Like I said, each car/van is different. I got 18 psi max with stock system and 2 cold starts. Others claim they can go higher in boost.

turbocoupe
03-31-2006, 08:21 PM
ya i knwo what your say Guys but i have all that stuff in my car from boost gauge to air/fuel gauge to bigger 225 fuel pump to AFPR thanks for the look out

JohnnyLightning86
03-31-2006, 08:39 PM
I agree with Simon and Marcus86GLHS. Gauges are crucial in my opinion. Don't rely on visual inspection of a spark plug. I think it can vary a lot depending on the overall set up. A larger and better cooling IC probably makes the biggest difference. But I could also see where less restriction in the overall airflow might help as well especially on the exhaust side.

I ran 15psi on 804's for 3 years without any trouble, but since my car has a log intake, I would guess the restricted intake might help reduce the chance of detonation if less air is able to get in.

It would be interesting if we had more factual data to compare the different set ups.

turbocoupe
04-01-2006, 02:29 AM
well im having my computer sent out for 20psi setup and my injectors were my biggest issue.

GLHNSLHT2
04-01-2006, 02:56 PM
Gauges are #1. Every setup is different. I had to run 42psi base fuel pressure on +40s and was still lean at 12psi of boost with a stock head and 2.5 motor. Most run 34psi. Always monitor things closely with gauges and reading the plugs. If they're white you're way too lean. If they're black you're good :)

turbocoupe
04-02-2006, 01:04 AM
ya i know thanks buddy i have my gauges right were i want them to at eye level and i will check my plugs when i get the new computer too

Thanks
Joey

Bardo
04-02-2006, 02:47 PM
i ran 20psi on stock

turbocoupe
04-02-2006, 09:26 PM
^ and then what happen'd^

WVRampage
04-02-2006, 09:33 PM
18 -20 lbs only a few times and didnt have any problems I cant remember the fuel pressure right off hand its been a while since I did it.

Bardo
04-03-2006, 06:00 AM
^ and then what happen'd^
and then i ran it for a year got hit by some chick and sold it to someone that put the engine in a omni. as far as i know its still running

Murphy
06-16-2006, 03:49 AM
gotta look at whose running 2.2's and 2.5's too....you can run more boost on a 2.2 than a 2.5 with the same sized injector

BadAssPerformance
06-16-2006, 08:29 AM
In my '87 2.2L T2 Shadow I have run up to 27psi with the stock T03 (Turbo II) Garret on the highway thru the 42pph injectors on 100 Octane and with the CSX Stage II LM :thumb:

Keep in mind that the size of the turbo matters in this equation, a larger turbo flowing the same psi boost needs more fuel...