injecters
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
fuelinjectorconnection.com
Most tout FIC for injector information and rebuild/new injectors.
Supporting vendor and apparently very well respected.
Also do a search for FICINJECTORS posts, many to be had..
Supporting vendor and apparently very well respected.
Also do a search for FICINJECTORS posts, many to be had..
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
If you are going to 350-400hp with an L98 TPI you will need slightly larger injectors, but the best advise would be to get the car dyno tuned once you complete your build. The size of the injectors, as long as you go above 30lb, will not matter as long as you get them tuned for your build. I have 42lb injectors, which are way big, but they are tuned to my set up.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
Increasing fuel pressure will help force more fuel thru the injectors.
that is why a TPI really responds well to an adjustable fuel pressure regulator they love around 45 psi in naturally aspirated form. This will not get you more than 50 h/p extra
350-400 hp will demand larger injectors, remember 85 vettes came with 24lb injectors standard.
This is what those of us with blowers do to we fit a fuel management unit that restricts the return to the tank to raise pressure in a linear percentage per psi boost. However a lot of boost needs bigger injectors.
that is why a TPI really responds well to an adjustable fuel pressure regulator they love around 45 psi in naturally aspirated form. This will not get you more than 50 h/p extra
350-400 hp will demand larger injectors, remember 85 vettes came with 24lb injectors standard.
This is what those of us with blowers do to we fit a fuel management unit that restricts the return to the tank to raise pressure in a linear percentage per psi boost. However a lot of boost needs bigger injectors.
Safety Car
Joined: Nov 2009
Posts: 3,963
Likes: 337
From: Adelaide South Australia
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
http://m.youtube.com/watch?feature=plcp&v=KBaueQZPAnY
You can view the dyno graph in my album if interested.
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Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Interesting comment. I have 42# injectors in my 396 Super Ram. The idle tends to wander more than I would like. I've considered downsizing the injectors. 24# injectors should be just fine for a mild build.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 762
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The reason I asked the question about idle quality with big injectors is that the ECM is limited as to how narrow a pulse width it can generate. Sometimes it tries to go narrow because the injectors are too large and hits the limit. Then you have too much fuel, especially at idle and in open loop.
My stock L98 idles at 2.2ms pulse width. The ECM is set to a minimum pulse width of 1.693ms. If it calculates a value lower than that it uses that number instead.
In closed loop mode the ECM can open the IAC to compensate for the extra fuel, but then you get high idle speeds and wandering idle as the ECM tries to keep the idle speed down. It gets stuck in this loop of lowering idle speed -- it's too rich so add IAC air -- the idle speed goes up -- need to lower idle speed...
My stock L98 idles at 2.2ms pulse width. The ECM is set to a minimum pulse width of 1.693ms. If it calculates a value lower than that it uses that number instead.
In closed loop mode the ECM can open the IAC to compensate for the extra fuel, but then you get high idle speeds and wandering idle as the ECM tries to keep the idle speed down. It gets stuck in this loop of lowering idle speed -- it's too rich so add IAC air -- the idle speed goes up -- need to lower idle speed...
Race Director
Joined: Sep 2003
Posts: 16,834
Likes: 337
From: Database Error Indiana
24s will do the job but you will probably need a bigger fuel pump. My stock pump did not keep up at around 350 flywheel hp.
Drifting
Joined: Aug 2010
Posts: 1,704
Likes: 8
More specs about your build...heads #,cam#,intake mods ...if your numbers are effective (400 hp) let say 24-26 lb/h and an high flow fuel pump.You can compensate a slightly large injectors size lowering your fuel pressure on fuel pressure regulator screw.