Help! 26lb Injectors.
Thread Starter
Safety Car
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From: Cape Coral FL
Help! 26lb Injectors.
I have a 99 FRC. I understand that in 1999 GM went from 28.8 lb/hr injectors to 26 lb/hr injectors. I currently have around 348 rwhp and 356 rwtq. What amount of hp/tq are the 26lb/hr injectors good for? I'm thinking of going with a H/C in the spring and am now wondering if I should go with 30lb/hr injectors. Also, If I change out my injectors now, will I need a tune to balance out the extra fuel delivery? My common sense says no, the computer will re-learn them. Any experience? Thanks. :confused:
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Re: Help! 26lb Injectors. (ArKay99)
After punching in your numbers on this worksheet http://www.rceng.com/technical.htm#WORKSHEET It appears that your 26's are working just fine. If you did upgrade to the 30lb injectors, you would need to tune the computer for the new injectors.
VR :cheers:
[Modified by vetterdstr, 5:53 AM 11/30/2003]
VR :cheers:
[Modified by vetterdstr, 5:53 AM 11/30/2003]
Safety Car
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From: Albuquerque NM
Re: Help! 26lb Injectors. (ChasNMe)
The equation most people use to calculate how big your injectors have to be is VERY conservative, it uses a BSFC factor which works well for older head design, carberator cars, not for LS1's. I ran the 26 pound injectors on my heads/cam car which put out 413 rwhp, so guess 485 crank hp. They were at 85% duty cycle, so that was the upper end of their usefulness. I switched to the 28 pounders from a 97 Vette, they will support your fuel needs till you go to a BIG cube or supercharger motor. Talk to the good tuners, they'll tell you not to go to the SVO 30 pounders for a variety or reasons: They are 38 pounders at our fuel pressure i.e: TOO BIG, they NEED tuning to work on our cars, idle fuel control can be a problem, spray pattern is different then ours, etc, etc.
IMHO you're fine now, but in the 400 to 500 rwhp range, get a set of cleaned and balanced 28 pound injectors. :seeya
IMHO you're fine now, but in the 400 to 500 rwhp range, get a set of cleaned and balanced 28 pound injectors. :seeya
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From: Scottsdale Arizona
Re: Help! 26lb Injectors. (ArKay99)
I have a H/C car 415rwhp.....my car was feeling like it came up on a big hill at about 5000 rpm. Sure enough according to my scanner my injectors were at 80% dc at 4400 rpm. I installed the SVO 30# injectors ( they flow at 34# -36# due to the higher fuel pressure on an LS1) and retuned. My car runs awesome and pulls great all the way to redline. I would highly recommend these injectors. I paid $265 for them and it took me about 1 1/2 hours to install.
Have them installed when you get your heads and cam then use LS1 edit to tune.
[Modified by goodhands, 2:54 PM 11/30/2003]
Have them installed when you get your heads and cam then use LS1 edit to tune.
[Modified by goodhands, 2:54 PM 11/30/2003]
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Re: Help! 26lb Injectors. (6Speeder)
I had 36 lb injectors on my car (came with the ATI kit) when I was running 530 Hp. After taking traces it was discovered that the 36 lb injectors were running over 100% duty cycle...
So I am confused as to how you arrive at the conclusion that 26 or 28 lb injectors are good for 480 fwhp :confused: No flame intended... just wondering how that works...
VR :cheers:
So I am confused as to how you arrive at the conclusion that 26 or 28 lb injectors are good for 480 fwhp :confused: No flame intended... just wondering how that works...
VR :cheers:
Drifting
Joined: Nov 2001
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From: Jacksonville Florida
Re: Help! 26lb Injectors. (vetterdstr)
I am running 42's (GM units for new 3.8 liter supercharged motors, a very fine but expensive injector). That is a bit more than the chart says I need (36) but I want a low duty cycle due to the way I operate the car. RWHP is in the signature, I expect with final tuning these numbers will improve by about 10 each.
I had some bad luck with SVO 30's, one went bad while road racing at Road Atlanta and took a piston with it. On the flow bench that injector was flowing 20% less than the other 7. No blockage in the injector, and I had been running the SVO's for over a year with no problem, though this was my first really hard run at a road racing event. Upon inspection my engine builder noticed evidence that the Ford injectors were rubbing against the back side of the fuel rails - no question fuel would be partially blocked. The SVO's are quite a bit longer than the stock GM units, no doubt the cause. So if you road race your car (and even if you don't) be careful on the Ford injectors. No flames please, I know many here run them (as I did) with no problems.
Les :cheers:
I had some bad luck with SVO 30's, one went bad while road racing at Road Atlanta and took a piston with it. On the flow bench that injector was flowing 20% less than the other 7. No blockage in the injector, and I had been running the SVO's for over a year with no problem, though this was my first really hard run at a road racing event. Upon inspection my engine builder noticed evidence that the Ford injectors were rubbing against the back side of the fuel rails - no question fuel would be partially blocked. The SVO's are quite a bit longer than the stock GM units, no doubt the cause. So if you road race your car (and even if you don't) be careful on the Ford injectors. No flames please, I know many here run them (as I did) with no problems.
Les :cheers:
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From: Clouds Over California
Re: Help! 26lb Injectors. (vetterdstr)
I had 36 lb injectors on my car (came with the ATI kit) when I was running 530 Hp. After taking traces it was discovered that the 36 lb injectors were running over 100% duty cycle...
So I am confused as to how you arrive at the conclusion that 26 or 28 lb injectors are good for 480 fwhp :confused: No flame intended... just wondering how that works...
VR :cheers:
So I am confused as to how you arrive at the conclusion that 26 or 28 lb injectors are good for 480 fwhp :confused: No flame intended... just wondering how that works...
VR :cheers:
I made 430/400 rwhp/rwtq on my old 97 H&C car. They had the 28lb injectors. That is 500bhp...they held up to 6800 rpms at 12.9-13.1 AFR.
I think for FI however you have to have a lot of injector...not only for fuel delivery..but to compensate for the MAF getting maxed out by the FI, having bigger fuel injectors allows the tuners to compensate for the lack of MAF reading when it gets maxed out. I think it is the PE tables vs RPM or something like that...I am not a tuner just a wrench turner when forced to be.
But you are not confused. I would say the highest hp for 26lb injectors is 480bhp...at 500bhp 100% duty cycle is not good...in fact it is recommended that the injector not run over 85% duty cycle...it also depends on the quality of the injector...some can be hammered more than others.
Safety Car
Joined: May 2000
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From: Albuquerque NM
Re: Help! 26lb Injectors. (vetterdstr)
I had 36 lb injectors on my car (came with the ATI kit) when I was running 530 Hp. After taking traces it was discovered that the 36 lb injectors were running over 100% duty cycle...
So I am confused as to how you arrive at the conclusion that 26 or 28 lb injectors are good for 480 fwhp :confused: No flame intended... just wondering how that works...
VR :cheers:
So I am confused as to how you arrive at the conclusion that 26 or 28 lb injectors are good for 480 fwhp :confused: No flame intended... just wondering how that works...
VR :cheers:
[Modified by 6Speeder, 10:50 AM 11/30/2003]
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Re: Help! 26lb Injectors. (6Speeder)
I appreciate you sharing your experinece. FWIW, Ease scanning software will actually register +100% duty cycle for an injector. In fact I have seen numbers as high as 150% on a S/C engine that had too small of injectors.
VR :cheers:
VR :cheers:
Drifting
Joined: Nov 2001
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From: Jacksonville Florida
Re: Help! 26lb Injectors. (vetterdstr)
That is 100% correct, you can indeed go over 100% duty cycle, I did on my blower motor as well, peaked at 125% - went and got bigger injectors the next day.
Les :yesnod:
Les :yesnod:
I appreciate you sharing your experinece. FWIW, Ease scanning software will actually register +100% duty cycle for an injector. In fact I have seen numbers as high as 150% on a S/C engine that had too small of injectors.
VR :cheers:
VR :cheers:
Safety Car
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From: Albuquerque NM
Re: Help! 26lb Injectors. (ZO6Les)
That is 100% correct, you can indeed go over 100% duty cycle, I did on my blower motor as well, peaked at 125% - went and got bigger injectors the next day.
:cry
Thread Starter
Safety Car
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From: Cape Coral FL
Re: Help! 26lb Injectors. (vetterdstr)
FWIW, I have a new maf that runs on a higher frequency that does not run out.
VR :cheers:
VR :cheers:
1: Can the MAF frequency lookup tables be re-flashed or are they in rom?
2: At the top of this thread you stated that my injectors are good to about 390hp. If I use the aprox 15% correction factor to extrapolate 347.3rwhp, that comes to 399.395. Were you stating 390 is rwhp or crankshaft hp? If that is the case my injectors may be on the hairy edge.
Another factor is, I have a VaraRam. That will give me small boost (approx 1lb.) at 60mph so I theoretically could be making 420 crackshaft hp. I do know that the car gets stronger the faster I go and 20hp is realistic as a power gain here. I am concerned about leaning out the engine if I get on it while going at 60mph or above given the above factors. :confused:
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Re: Help! 26lb Injectors. (6Speeder)
Yep, the MAF is aftermarket and I think it has been on the market for a while. Contact MMS for information on the MAF I am talking about. :)
VR :cheers:
VR :cheers:
Team Owner
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From: San Jose/Bear Valley CA
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Re: Help! 26lb Injectors. (ArKay99)
As far as the MAF goes... contact MMS for information about the specs. Did you use that site I posted to figure your injector needs?
VR :cheers:
VR :cheers:
Thread Starter
Safety Car
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From: Cape Coral FL
Re: Help! 26lb Injectors. (vetterdstr)
As far as the MAF goes... contact MMS for information about the specs. Did you use that site I posted to figure your injector needs?
VR :cheers:
VR :cheers:
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Re: Help! 26lb Injectors. (ArKay99)
I have some info regarding injectors.
http://www.vetteguru.com/mods/howto
Also, an injector running 80% plus for a long time is a bad thing. It tends to overheat.
[Modified by kewlbrz, 10:14 PM 12/1/2003]
http://www.vetteguru.com/mods/howto
Also, an injector running 80% plus for a long time is a bad thing. It tends to overheat.
[Modified by kewlbrz, 10:14 PM 12/1/2003]