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heads and cam swap and no hp gains

This is a discussion on heads and cam swap and no hp gains within the Internal Engine forums, part of the LSx Technical Help Section category; I have a 2002 camaro motor with a 4l60e tranny. I recently installed a set of 215cc AFR heads with ...

  1. #1
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    2010 sprint car

    heads and cam swap and no hp gains

    I have a 2002 camaro motor with a 4l60e tranny. I recently installed a set of 215cc AFR heads with a 59cc chamber and a G5x4 cam from LG motor sports and after tuning it with HP tuners on the chassis dyno I was only able to get about 360hp at the rear wheels. We've checked everything I know of and we're still about 100 hp down. Any ideas or thoughts would be helpful.

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    01 vx hsv gts c4b

    Is the auto good is it being strapped down properly what other mods did you do it may not be breathing properly or running out of juice

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    Member jsmith564`'s Avatar
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    i was also thinking fuel...

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    Senior Member Z28_Driver's Avatar
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    Most likely fueling problem. Could also be exhaust and intake if not the fueling issue.

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    I have a trick flow fuel regulator that is set at 60psi. One of the guys there watched the fuel gauge during one of the pulls and said the pressure didn't drop. I'm running headers, an underdrive pulley, and that's it for mods. Wouldn't we see it on the HP tuner if I was running out of fuel? I'm using the stock injectors, the guy that dynoed the car said I had plenty of fuel, but I've been wondering if that could be the problem myself. Any suggestions on how to determine if I have enough fuel? That motor has the LS6 intake, we did a smoke check for vacuum leaks and didn't find anything for leaks. We did a pull in 2nd gear to see if that changed anything and the #'s were the same. We changed tire sizes and the #'S were the same. After all of the dyno time we did a leak down on the cylinders and they were all less than 5%.
    I appreciate the help, Thanks
    Last edited by adamwackel; 06-17-2011 at 09:52 AM.

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    Has anyone heard of lifters going bad? Is it possible that I'm not getting the lift that the cam is giving me?

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    Is your throttle body opening up all the way when you press the pedal to the floor?

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    Yes. we actually pulled off the MAF and filter for a pull to watch it.
    When I installed the cam, I didn't degree it in, I was told by LG just to line up the dots and it will be fine. Could that be the problem?

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    Lifters either usually get stuck or collapse. I don't think that's your issue though.

    As far as injector sizing, that is a straight up formula.

    Assuming you use a BSFC of 0.5 (non turbo or SC car), use a base HP of say 450, and a duty cycle on your injectors of no more than 80%....

    Your approximate injector size would be about 35 lbs/hr, which would mean your stock 28-lb injectors are inadequate.

    Were any other cars DYNO'd that day?

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    No there weren't any other cars on the dyno that day.
    I was told that stock injectors are fine by LG. So that's what I tried, I do have a set of 42# injectors I could try to see the difference when I get it back together.

    Another thought, I didn't have my cam degreed when I put it in, I just put it in dot to dot. Could the cam be far enough off that it would cause some problems?
    Last edited by adamwackel; 06-17-2011 at 03:20 PM.

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    With HP you can tell if your injectors are being maxed out or not, so don't just change them yet. Get back on the dyno and check those first. Hopefully they do that free of charge, but likely not.

  12. #12
    What does the dyno graph look like? HP should be peaking around 6500rpm, and torque just under 5000rpm (converter dependant). What rockers are you using? Finally, and most importantly, are you SURE it's not running on 7 cylinders?
    Last edited by Marc 85Z28; 06-18-2011 at 06:14 AM.

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    Senior Member Z28_Driver's Avatar
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    Quote Originally Posted by adamwackel View Post
    Has anyone heard of lifters going bad? Is it possible that I'm not getting the lift that the cam is giving me?
    Probably not lifters. You would hear that problem.

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    Whatever you do, you definitely don't want your injectors "max'd" out. 80% max duty cycle.

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    no wideband at the dyno?????/

    Quote Originally Posted by Z28_Driver View Post
    Most likely fueling problem. Could also be exhaust and intake if not the fueling issue.
    My dyno guy always gives me air fuel ratio with the wide band in the pipe. i don't see how you could tune without it. That's how you rule out a fuel issue.

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    I know guys do the dot the dot and it works but I always dial it to the card to make sure it's what you paid for

    It sounds strange no power I would've thought you pick up a little then tune for more bit tuned and no gain maybe try another tuner

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    How does it feel compared to the old setup?

    What type of dyno?

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    I recently finished up my car and during the tuning process I was having misfires and the car was not running properly at low idle.

    I'm using 63-lb Simein injectors for my set-up. After much diagnosis, and returning everything almost back to stock to eliminate everything that could be a cause, we found that it was the spark plugs we were using. We swapped the Autolite's out with some NGK's and voila. Car ended up making 540rwhp on 8lbs of boost.

    I had great fuel pressure the entire time ~ 60psi.

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    540 sounds nice.

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    Senior Member Z28_Driver's Avatar
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    Quote Originally Posted by the71ub4cm30 View Post
    My dyno guy always gives me air fuel ratio with the wide band in the pipe. i don't see how you could tune without it. That's how you rule out a fuel issue.
    Obviously there was a problem somewhere in the process. You might have found it. You don't have to know what your doing to open a hotrod shop.

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