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Didnt they run more boost than that with the KB test car in MM&FF, I am thinking that car had stock injectors??????? It made crazy power thats all I know!
 

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Snake Charmer
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Discussion Starter · #3 ·
trey193 said:
Didnt they run more boost than that with the KB test car in MM&FF, I am thinking that car had stock injectors??????? It made crazy power thats all I know!
Yea, thats what I was thinking. I need to get my boost gauge hooked up so I can see if I am hitting 17psi now. Im going in for a dyno tune and thinking I may just bump it to 19psi.
 

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I know a guy at my dyno shop who has a yellow 03 cobra with a Kenne Belle using the 3 inch upper which i believe is around 17 pounds with stock injectors and he dynoed at 633rwhp using his K.B chip and he has no isssues at all with the car and his air-fuel is 12.0-12.2 throughout most of the powerband.I am sure he is near his limit with that much power you would think.
 

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I was originally running 15-17# with stock injectors. It ran fine with diablo tune but my fuel psi was never turned up in the chip and I had issues with the BAP fighting with the stock pcm. When I added a 6# lower and stepped the boost up to 19-21# I added the 55lb injectors, but still had the fuel psi issues with diablo chip. It ran fine tons of low end but it was falling on its face above 4500 rpm. Now I have KB chip tuned for 55s and the fuel psi is up. BAP is definately working for increased volume now and the car pulls so much harder than before. I have stepped my boost back to 17# and it is a different car on the topend than before. I have come to conclusion it is more of a fuel psi and volume issue rather than the injector size. I think the stock 42s are probably close to there duty cycle limit above 600-625 rwph, but obviously there are folks making the HP with em. By the way that last thread from Hammer and MJCHIP datalogging Hammer's cobra was very informative. I posted an excel spreedsheet showing my stock pumps duty cycle pegging around 4600 rpm and fuel psi quickly dropped off and this is with the BAP off and 55# injectors running 19-20lbs boost. So thats my .02 cents worth... :)

Jon L
 

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Discussion Starter · #6 ·
Dustoff said:
By the way that last thread from Hammer and MJCHIP datalogging Hammer's cobra was very informative. I posted an excel spreedsheet showing my stock pumps duty cycle pegging around 4600 rpm and fuel psi quickly dropped off and this is with the BAP off and 55# injectors running 19-20lbs boost. So thats my .02 cents worth... :)
The current diablo tune I have seems to run fine at stock fuel PSI but I still have the BAP inline to help with the pegging FPDM Issues just in case. I have no problem keeping the BAP for insurance. The main reason I am asking is that I will have a tuner in my car over the week(a real tuner not just a chip burner) so that I can make sure its done once and for all, I have tried 6 tunes to date and none are right yet and its getting old fast. Im just thinking I should put my 19psi upper on if I can get it tuned and others have done it.
 

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Shadowgray03 said:
The current diablo tune I have seems to run fine at stock fuel PSI but I still have the BAP inline to help with the pegging FPDM Issues just in case. I have no problem keeping the BAP for insurance. The main reason I am asking is that I will have a tuner in my car over the week(a real tuner not just a chip burner) so that I can make sure its done once and for all, I have tried 6 tunes to date and none are right yet and its getting old fast. Im just thinking I should put my 19psi upper on if I can get it tuned and others have done it.
Just curious what Fuel PSI are you seeing with stock injectors above 4500 rpm ? Is it just constant from idle to WOT at 39-42 psi or does it progressively climb with RPM ?

Thanks, JL
 

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HIGH ROLLER said:
I know a guy at my dyno shop who has a yellow 03 cobra with a Kenne Belle using the 3 inch upper which i believe is around 17 pounds with stock injectors and he dynoed at 633rwhp using his K.B chip and he has no isssues at all with the car and his air-fuel is 12.0-12.2 throughout most of the powerband.I am sure he is near his limit with that much power you would think.
I am not saying that this is not true, just hard to believe.:confused:
 

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chillfactor,
If you have doubts call and ask for Tom the owner of the business he can go over his numbers and everything he has done to his car.His number is 574-294-6541
 

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I have been around a lot of KBs lately and I have not seen those type of numbers from the stock injectors, but if the air temp is cool in your area, that my be the difference. We have been 90 or better everyday for as long as I can remember...........:mad:
 

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I think the real issue here is not whether you can run that much boost with the stock injectors. The concern will be for how long. Keep in mind 42 lbs injectors can only flow so much, BAP or no BAP. Don't kid yourself, if you plan on sticking with stock injectors, you should also plan on not turning the boost up to high. Otherwise, if you want more boost, go with the larger injectors. I personally feel that with some of the power numbers that some guys are putting out, the 55's are even on the small side. MJ's data log of Hammer's car proves this.
 
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