WOT, nothing after 4000rpm....
10-23-2008, 10:47 AM
#1
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WOT, nothing after 4000rpm.... Is it possible to tune a H/C/I/E car to use the stock injectors? Right now it feels like its running out of fuel at about 4k at WOT....
Is there a way to check and see if that is indeed the problem?
-Rick
Is there a way to check and see if that is indeed the problem?
-Rick
10-23-2008, 11:12 AM
#2
If you have installed ported heads, larger cam and are trying to run on a stock tune, they
is very likely the source of your problem (and soon to be the source of many more if you
don't get that taken care of). At the very least, get a mail-order tune, better yet, get
some time on a tuner's dyno and have it done right.
How big is the cam? You may want to consider larger injectors.
My old setup (22x/23x cam, LE2 heads) required 30# SVO injectors ... my new one will run on 42s.
If you already have a custom tune, the tuner should have told you if you were exceeding 85% duty cycle.
is very likely the source of your problem (and soon to be the source of many more if you
don't get that taken care of). At the very least, get a mail-order tune, better yet, get
some time on a tuner's dyno and have it done right.
How big is the cam? You may want to consider larger injectors.
My old setup (22x/23x cam, LE2 heads) required 30# SVO injectors ... my new one will run on 42s.
If you already have a custom tune, the tuner should have told you if you were exceeding 85% duty cycle.
10-23-2008, 02:00 PM
#3
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I do my own tuning. They are above 85%. I think 120% has been seen, lol.
Heavily ported and polished heads, decent sized cam... 224/224 @ 112 etc....
How much will injectors run $ wise...? I've never actually looked into it...
Rick
Heavily ported and polished heads, decent sized cam... 224/224 @ 112 etc....
How much will injectors run $ wise...? I've never actually looked into it...
Rick
10-23-2008, 02:02 PM
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Seemed to do "ok" on the stock tune, I backed the fuel delivery down by 20% awhile back to see if it affected mileage and if it would clear up my running rich issue when cruising.. after the change it seems a little worse
10-23-2008, 02:06 PM
#5
i am not claiming to be a tuning master i am really still learning but if you feel like youre going static over 4k, and you are seeing 120% duty cycle, i think that backing the delivery down will just add to the problem as youre taking more fuel out making em try even harder, could you bump the pressure up? that will bump the effective flow rate on the injectors wouldnt it? i think that 30#'s would be the trick but agian i am not an expert, im sure theres more opinions out there
10-23-2008, 02:26 PM
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I didn't back the delivery down to solve that problem, just a MPG test...
I'm looking at a set of 30# injectors right now on EBAY... Seems like alot is involved in swapping injectors... adapters and whatnot...
-Rick
I'm looking at a set of 30# injectors right now on EBAY... Seems like alot is involved in swapping injectors... adapters and whatnot...
-Rick
10-23-2008, 02:31 PM
#7
I'm not trying to be an *** here, I'm just trying to help you out.
Please don't take this the wrong way.
And you don't see a problem with this?
30 or 32s should be just fine in that case.
http://www.racetronix.com/621020.html
You can generally find a set of used ones for under $200 if you hit the "for sale" section of most message boards.
Not at all, there are aftermarket injectors which fit an LT1 fuel rail and wiring
harness without modification or adapter. Some of the newer SVO injectors
require EV6/EV1 adapters to work.
Please don't take this the wrong way.
http://www.racetronix.com/621020.html
You can generally find a set of used ones for under $200 if you hit the "for sale" section of most message boards.
harness without modification or adapter. Some of the newer SVO injectors
require EV6/EV1 adapters to work.
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10-23-2008, 02:37 PM
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I know thats a problem, anything over 85% duty cycle isn't the best...
During WOT testing/tuning I saw 120% come across on the data... I know thats not good, thats why I'm looking into this now...
Since the car was built its been putted around town and junk, never Driven at WOT, so Now I'm dealing with a fuel problem...
I was reading about the SVO injectors.
I found some 30lb Bosch injectors on Ebay for $11 right now, I might try to snag them for testing....
Also, is it hard tuning for different injectors?
During WOT testing/tuning I saw 120% come across on the data... I know thats not good, thats why I'm looking into this now...
Since the car was built its been putted around town and junk, never Driven at WOT, so Now I'm dealing with a fuel problem...
I was reading about the SVO injectors.
I found some 30lb Bosch injectors on Ebay for $11 right now, I might try to snag them for testing....
Also, is it hard tuning for different injectors?