I have 50# inj. now, and they are maxed. I need bigger, but don't know if I need 55 or 72. I hate to spend all that money and only jump 5 pounds. But its a atreet car, and I don't know how the 72's are on the street. I have an ext. chip, and will have it updated. Thanks for any help!
Which inj.-55's or 72's?
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Richard Inglett
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- Jan 22, 2002
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10's - 72's, Low 11's - 55's
I like the 55's but there is not much difference between them and what your 50's can do. Maybe two tenths difference. Very high 10's and low 11's are possible with both.
I like the 55's but there is not much difference between them and what your 50's can do. Maybe two tenths difference. Very high 10's and low 11's are possible with both.
Intercooler
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What pump do you have? It makes a world of difference with what you can get out injectors when the supply is there. In some cases 83's wouldn't be enough if the pump can't supply them. I had 55's and 83's and liked the 55's better. If I had to do it over again and for most of our goals I would get 65's.
either will supply enough fuel with proper pump to make enough hp to blow up a stock block. i run 50's in one car and 72's in the other. with the 3.5 ls1 sensor and translator combined with the ME-16 pos chip, its unreal how streetable this car is with 72's. i can trim it back and adjust it so it gets killer fuel economy. idles smooth and iknow i have plenty of fuel for when i tun up the wick.
Bob Bailey is running 72/75's in his car right now. You can be sure that he will burn you a sweet chip for the 72's. I see no reason in going up in such a small increment to 55's. Might as well step up to the 72's. They are the same price anyways aren't they? Bob can mod your ECM as well.
Intercooler
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Clayton,
Have you tried 72's yet? Until you do, it will be hard for you to see. With these large injectors the idle is higher and the car is rich down low at all times. If I can lower my idle and richness a little by using 65's I think it would be well worth it. Most of us should have enough fuel with 65's to get the job done.
I like the 75's
No probs with a 750 idle. No probs with over-richness. No probs with driveability.
I'm sure the 65's will be fine too.
I like the Delphi's a little more than the Siemens due to the better spray pattern.
TB
No probs with a 750 idle. No probs with over-richness. No probs with driveability.
I'm sure the 65's will be fine too.
I like the Delphi's a little more than the Siemens due to the better spray pattern.
TB
Steve Wood
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Sam, even adjusting for the short times which are a bit slow, I would think you have at least another couple of tenths left in the 50's without pushing them. I would suspect that the problem is with the delivery system IF the egts or wb o2s show that it is lean.
If upgrading for the future, I would consider the 75s, or 72s rather than such a small upgrade. Carl Ijames has tweaked his own chip to pass emissions at a 650 rpm idle with the 72s so I think any rich idle problems are in the chip rather than in the injector. The 75s are a bit richer at low pulse widths than the 72s apparently. Mine work very well with the ME and a faster idle.
I am personally not familiar with the 65s but I am sure someone makes a decent chip for them as well.
If upgrading for the future, I would consider the 75s, or 72s rather than such a small upgrade. Carl Ijames has tweaked his own chip to pass emissions at a 650 rpm idle with the 72s so I think any rich idle problems are in the chip rather than in the injector. The 75s are a bit richer at low pulse widths than the 72s apparently. Mine work very well with the ME and a faster idle.
I am personally not familiar with the 65s but I am sure someone makes a decent chip for them as well.
Thanks for the replies. I need to call Bob B. and see what to do. I think 75's are the way to go, just want to be sure the pump can handle it. I say my 50's are maxed because even on the eighth mile track, I see 107% dc, and still need to be faster, so I feel like I'm pushing it. Don't want to break stuff if it can be avoided, know what I mean? It sounds like Bob has the 75's sorted out pretty good. Should I be concerned with the pump?
See Bob's (and the rest of the guy's) replies and then read again what I said. If you haven't tried one of Bob's Extender chips, you just won't understand 
I have 65's in mine, but I never had an opportunity to do a chip for them. They run like the 50's with some little differences. They dont need as much accel pump squirt as the 50's did, but they do seem to have a lean spot like the 50's, just a different spot. I'm working on getting the lean sag out of my program. Once I do, I'll have a good idea how much more fuel they need at what pulsewidth and could probably do a chip for them. But Bob is probably more "yer man" than I am. He or Steve (MexE) can set you up in ANY case.
Thought
After reading and learning. I agree with Gene and Steve.
Plus the one thing you have not mentioned. Was the pump you are running. Which steve pointed out.....
I'd would check what you have first. Maybe Max 16 position chip.
Would do the job...Can always go to the 72's if need be. Just a thought........ Rob
After reading and learning. I agree with Gene and Steve.
Plus the one thing you have not mentioned. Was the pump you are running. Which steve pointed out.....
I'd would check what you have first. Maybe Max 16 position chip.
Would do the job...Can always go to the 72's if need be. Just a thought........ Rob
LAST thought
I noticed your 60 ft times as being 1.90.
I would try first getting that down. As the first 60 ft. mark is
so important.
Maybe that will give you what you want. Could be over extending trying to makeup time lost on the line......And where do you want to go time wise? Just curious.That could also help in decision......Anyway good luck you got great inputs
HTH'ed Just trying to give ideas
I noticed your 60 ft times as being 1.90.
I would try first getting that down. As the first 60 ft. mark is
so important.
Maybe that will give you what you want. Could be over extending trying to makeup time lost on the line......And where do you want to go time wise? Just curious.That could also help in decision......Anyway good luck you got great inputs
HTH'ed Just trying to give ideas
I'm trying to go 10.9's, and I know my 60' times suck. But even taking that into account, thats not a ten second run. Maybe low elevens. And I'm driving those 50's pretty hard to do that now. Don't want to push them harder. I'm still undecided. Its gonna cost me a lot to go double pumper, 75's, ecm mod, and chip. Damn near $1000. I just want to be safe. You can't have too good of a fuel system.
