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Scott R's Avatar
 
Join Date: Feb 2001
Location: Aspen CO US
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Post Need Larger Injectors

I think I need larger injectors. I have the Huntley Air/Fuel monitor in my car and I can get the injector % to cross the 100% marker. Next question, anyone have the part numbers for larger injectors? Will simply upgrading my 85.5 N/A injectors to Trubo injectors do the trick? I am trying to get the mixture right on my supercharger setup and not having much luck every time I put the 19psi pulley on I get detonation at idle.

Old 08-07-2001, 06:35 AM
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your using stock injectors on a supercharged setup??? oh man!!...u should atleast use a turbo injectors...last 3 numbers on injectors(803 stamped in the injectors)dark green
Old 08-07-2001, 07:28 AM
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What about retarding the timing rather than new injectors???



This is the boost timing retard unit from MSD, it reads boost and pulls timing out by the amount you set from an in-cabin dial, based on the boost, so as boost climbs more timing comes out to protect against detonation...

www.msdignition.com

Lots of Mustangers use this item very successfully, before going to larger injectors. It could give you a lot of flexibility with your pulleys, and allow adjustment on the fly...

Just a thought,
Rich
Old 08-07-2001, 07:35 AM
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19 psi? Do you still have the stock pistons? If you do, this amount of boost will not work, now matter how big the injectors are. I would guess 10-12 psi max on race gas w/stock pistons.

For reference, my injectors are supposed to be 43lb at idle compared with about 30lb I believe for the stock turbo injectors. With my setup, I'm hitting between 80 and 100% duty cycle at 6000 rpm.

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Erick

86 951

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Old 08-07-2001, 08:02 AM
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The 19psi pulley and the 12 and 10 are all too much. right now it's only working with the 7Psi pulley. I would like to at least get the 10 working. Anything above the 7 has idle detonation, and of course gets worse as you go up. This motor still has stock pistons and rings. Likewise above 7 the mixture is impossible to control.
Old 08-07-2001, 08:06 AM
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If you want my turbo injectors, I'll sell them to you reasonably. They were in good shape when i replaced them with the larger injectors.

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Erick

86 951

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Old 08-07-2001, 09:09 AM
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Yes I would be very interested! Please email me sramnit@home.com
Old 08-07-2001, 09:17 AM
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Quote:
Originally posted by Scott R:
The 19psi pulley and the 12 and 10 are all too much. right now it's only working with the 7Psi pulley.
Get a water injector. It will give you some relief on the detonation since you have no intercooler. Richard
Old 08-08-2001, 12:40 AM
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Scott, don't bother with 951 injectors, stock or aftermarket. What do you think I tried before going with additional injector system? The 951 use an abonormal resistance compared to industry standard high and low impendence injectors. I checked the ohms after installing a set and finding that the engine would only turn over without starting.
I ran 7 psi on my motor and the pistons are all cracked except for one. I found 7 cracks shared with the 3 pistons. I have new oversized 951 pistons($$$) and shotpeened and resized 951 rods. Timing retard is with J&S safeguard that retards upon sensing knocking. You must also do some intercooling to run that much boost. Because of the setup,
you may only be able to run a water cooling injection as there does not seem to be any room for an air-to-water intercooler and piping for an air-to-air unit requires extensive cutting/welding/fabrication.
Just make sure that you always have water in there if you do decide to do it as it would be disasterous if you ran out of water during a high boost run.
Old 08-11-2001, 01:57 PM
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But if you decide to do larger injectors, call up RC Engineering and see what they can do. You may need an MAF kit to control them, as I do not have any experience with MAF.
Otherwise you may end up running rich at idle, ect.

Old 08-11-2001, 02:00 PM
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