H.p. gains from larger injectors ??

jckleewein

New member
Dec 13, 2008
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Broomfield, Colorado
I had 80% over in my truck, and it idled clean. It would puff out a pretty good cloud of smoke if you got on it real hard from a stop or even if you were rolling along the highway, but it cleared up really quick. It was pretty easy to drive it on the street without smoking people out. I had the same twin combo you are running and a high RPM cam from SoCal.

edit: I just reread your sig. I was running the same large turbo as you, but my small turbo was an HTT SS366.

X2 I am running 80% in my truck right now. I have altitude playing against me. I have no smoke or haze at idle, but when I get on it real hard from the start or roll into the pedal, it smokes pretty decently.
 
Sep 10, 2008
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Morehead City, North Carolina
I've got a set of 45% overs and waiting to get the stage II cp3 back from floor it to install soon. I wondered myself what would be the possible gains and how smoky it would be with my gt4088r but obviously on a much smaller scale since most of you have built motors, twins, much larger injectors etc....
 

bigbird

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Sep 18, 2006
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Edmonton, Alberta, Canada
josh what kind of power did you make ? or e.t. ?

I've got a 66 and 4718. trapped 130mph at 7200 lbs. ran 10.80's. running socal 100% overs. I wouldn't go over 60% if you are concerned about smoke. Mine doesn't smoke at idle and will haze just a bit if you are friendly to the pedal, if you mash it, it will smoke until the big charger lights.
 

S Phinney

Active member
Aug 15, 2008
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Quncy, Fl
I run 65% overs now and it doesn't haze or smoke at idle. It will smoke really well when getting on it. It does take some time to tune so that you have good response and less smoke. My fuel mileage isn't much worse than when the truck was stock and running a tuner. You will have more issues that you may not like when going bigger along with the possibility of the injector life being shortened when going big. Stay 60% and under and you usually run into less problems.
 

S Phinney

Active member
Aug 15, 2008
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Quncy, Fl
Another thing I can tell you is there will be a lot of difference between 45 and 65 overs. I like the 65 better but was doing it around going to twins too.
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
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slc tuah
i thought bigger injectors shorter pulse = longer life ????

Longer life of the motor yes , In theory anyway but most end u8p right back to the big duration , hell with my 130 overs I was back up to almost a stock sticks race tune , gotta love stoker pumps :D.
 

ChevyDieselLLY

Whats A Budget???
Apr 1, 2008
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MI, NC, now Hawaii
i will have 100% overs in my truck with a S472. Dustin from DA DD with 100 overs and a S475 and it didnt smoke or haze at idle. but if he got on it it would of course. he also has a custom that has a modded CP3 with 100 overs and a stock turbo and that thing didnt smoke at all. granted it was a very small tune but it moved for the tire size and lift. i think it all has to do with how much time you take to tune your truck.
 

SteveFord

What's Next?
May 8, 2008
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Iowa
Im in the process of tuning in my truck with 30% overs. Im trying to make the same power with the stock injectors to help the engine live longer until I do something with it. If you could get it dialed in right I would go as big as your tuner or you feel comfortable with and work in it. I started out with my tunes small and am working my way up to get it dialed in. I would think with your combo that you'd be better off with 45%'s on up. Better to try and tune it in with them on the bigger side than not going big enough.
 

xcablb7

New member
Feb 8, 2009
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Fall River
yeah after talking to someone with a similar setup i may just go with 100's, i'm not gonna race it to it's max potential but would be nice to get some good dyno numbers, i'm not putting a bar in it so all out won't be an option
 

JD4440

<< Lo-Carb Monster
Feb 27, 2009
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Orlinda, TN
I dyno'd before and after I installed 45 overs. Can't find the actual sheet but it was right at 480 stock and avg'd 506 after wards. Went from 3100 to 2375 (?? Josh would know) PW. Also went from a best 13.51 to a 12.99/13.00
 

bullfrogjohnson

Big Girl!
Nov 20, 2006
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Locust, NC
what kind of injectors was he running ? how much power did he make ? I daily drive the truck so i will give up a little power for it to run a little cleaner, so I dont think i'm going to go with much bigger than 70%

Josh was running 60% extrude hones and it made 943hp and ran a best of 10.7 until he lost a piston. He was running a s366 under a 4718 though but you will be close. He also daily drives the truck.

Josh and I will both be going to 100% over the winter.
 
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JoshH

Daggum farm truck
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Feb 14, 2007
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josh what kind of power did you make ? or e.t. ?
Going off the HP calculators, I was pushing somewhere around 850 to 900 HP. My best ET was 11.13 @ 123.5 MPH. That was with a 2500 uS pulse on the tune. It was completely smoke free (other than a puff at launch). Here's a vid.

[youtube]DHQUnh4zac4[/youtube]
 

xcablb7

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Feb 8, 2009
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Fall River
awesome thanks looks like that is where i might end up, that is how i want it to run, smoke level, pw, power etc. i appreciate the info
 

xcablb7

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Feb 8, 2009
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Fall River
i've got 2 extra sets of injectors, one set had perfect balance rates but smoked blue at idle the other set i thought had an intermittent miss but was another problem, so there fine could the ones that smoked just be old dirty tips ? if i use those i can save the others as good stock one's