60lb injectors are good for 480hp at 12:1 AFR, I imagine that Jeff's car was tuned closer to 11:1 which is past rich best torque, I would look at leaning the tune out to around 12:1, you could even gain power, and not max out the injectors, I know Jeff had custom cams, and and a "shorter runner" intake, but his motor was never over 400whp that I recall.
I should ask what indicates your injectors are maxed out? low Lambda reading on a wide band? is fuel pressure sufficient?
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07:36 PM
nosrac Member
Posts: 3520 From: Euless, TX, US Registered: Jan 2005
Yep I bought Jeff's car need a new AFR gauge when jeff had it a mouse chew throw the wires. Looking to switch to a DW300 fuel pump and see what it will do on E85. I don't think i need bigger injectors but he told me that he has them maxed out as is. So i don't know if its not tuned right or what.
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12:40 AM
3.1 88FieroGT Member
Posts: 233 From: antigo, wi, usa Registered: Jun 2010
Originally posted by 3.1 88FieroGT: The point is go big or go home.
Edit: - Because you're new - You aren't wrenching on a DSM, the idea is to buy parts for your specific need. Flooding your engine isn't going to take you to the moon. 60# injectors with a medium duty cycle should be serving your needs, given what we all know about the car you now own. If that's not enough then you might try 80#, but for the love of god... 95# is overkilling overkill. There are costs and disadvantages to using larger injectors, specifically idle quality.
[This message has been edited by L67 (edited 03-09-2012).]
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01:59 AM
Mar 11th, 2012
3.1 88FieroGT Member
Posts: 233 From: antigo, wi, usa Registered: Jun 2010
are you kidding me 4g63 evo's owners use 1200 cc injectors and thats a 4 cylinder. The point is go big or go home.
that doesn't mean there doing it right... lots of people run things suboptimal because they don't know any better, or are the blind following the blind. Personally, save the money and get a professional tune. Jeff ran a Haltech, that makes it easy to find someone capable of tuning it. I payed $4.15 a gallon today, my GTO only gets 19mpg average, I would hate to pay more because of a poor tune.
how many miles you have on it? Evo owners run huge injectors because they push 35+ lbs. of boost.
Almost a year and about 5,000 miles. They run 35psi because they have small 2.0 engines. I'm still faster than evo's even at 40psi. Pressure isn't a very good benchmark for power or speed.
They might have to have bigger injectors if they don't raise fuel pressure 1:1 with boost pressure.
If you are maxing out 60s you are doing something wrong, as was previously stated.
You want to run your injectors @ ~80% Duty Cycle max, running higher can overheat them. You also want 13:1ish AFR for N/A and 12:1ish AFR for boosted (Richer for cooling cylinder temperatures). Lean is power, too lean can melt pistons. 6 60lb injectors should support 480hp as previously stated, which is quite a bit. the thing with the 4 cylinders is they have 4 injectors, thus have to run higher # injectors to make the same power as 6 cylinders. Just because they have a smaller engine doesnt mean they need smaller injectors. Once you break into low impedence injectors, you then need to think about dual injector setups instead of single injector. This will give you more fuel flow when you need it, however still have good low RPM stability, AKA good idle quality.
if you run the biggest baddest injectors you can find, and run them at 1% duty cycle, what are you doing other than wasting them? In fact, at idle, the time it takes to open then close the injectors when they are so big, will rich out your mixture too much and flood the engine out. This can cause a rich out, which will cause your car to stall all the time at idle.
Do your math on your estimated HP, and injector size and amount, and find the right injectors for the application. Also, do dyno tuning at a local dyno, and get the proper tune for the vehicle.
[This message has been edited by Racing_Master (edited 03-12-2012).]
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05:22 PM
PFF
System Bot
3.1 88FieroGT Member
Posts: 233 From: antigo, wi, usa Registered: Jun 2010
Well that was the answer I was looking for.... When the car is cold it doesn't want to idle right away. Jeff the previous owner told me he could never get the iac hooked up right. It has a older Haltech in it and I was told that the old models had problems with the IAC any idea's.
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11:44 PM
Mar 13th, 2012
Silicoan86 Member
Posts: 1614 From: Savage, MN, USA Registered: May 2004
Well that was the answer I was looking for.... When the car is cold it doesn't want to idle right away. Jeff the previous owner told me he could never get the iac hooked up right. It has a older Haltech in it and I was told that the old models had problems with the IAC any idea's.
I suggest a new ECM if the haltech is unreliable with an IAC. I recommend you take your car to a shop familiar with Haltechs then, and see what they recomend. Or switch to a hacked GM ecm, since they a proven to work with GM sensors. I can recommend some shops in SE WI if your are so inclined. I know some people who are versed in Haltechs.
