too much money for no power
03-17-2012, 06:55 PM
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too much money for no power about a year ago i bought a 2001 trans am with a rod knocking, originally i was going to fix the car and just drive it. i watched a video too many on youtube and then wanted to build the car into a street beast. i bought an ms4, prc springs, push rods, iron 6.0 motor, stall, hand ported 317 heads, with 2.125 valve seats, 2.08 intake, 1.60 ex, weisco 12cc dome pistons, eagle 6.125 h-beams, stock crank, fast 102 intake, fast 46lb ls2 style injectors, godspeed(ebay) 102mm throttle body, tr6 spark plugs. i had this all assembled and finally got on the dyno and mildly tuned and the chevrolet dealership and so far i am only making about 350hp. could my tune be just that bad? the tuner told me he set the redline to 6200rpm. have i not reached the powerband of the ms4 or what? can someone help? i was hoping for atleast 480hp at the wheels.
03-17-2012, 08:28 PM
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I would say that 480 at the wheels was really optimistic. I just searched and it seems like most guys are making roughly 400-450 with that cam. So it could be the tune is accurate enough, how does the car run? Also what kind of exhaust do you have on the car? And do you have a Lid? With that cam simple exhaust and intake will be a bigger bottleneck then on a stock car.
Also what kind of stall do you have? You have to remember to that autos generally put down less power on a dyno. So 350
Also what kind of stall do you have? You have to remember to that autos generally put down less power on a dyno. So 350
03-17-2012, 09:06 PM
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6200 is the stock redline, and a poor choice to get the most out of that cam. You should be shifting several hundred rpm higher with your setup.
I didn't see any mention of headers in that mod list. Stock manifolds and/or exhaust will really hold that setup back, and I could definitely see you picking up ~50rwhp over the stock manifolds/cats/exhaust with that setup.
How about an air lid? I assume you have one, but it's not listed. If you happen to be using the stock lid, you're probably leaving about 15rwhp or more on the table there too.
How much faith do you have in your head porter?
Who did your tuning, and did they use a dyno during the tuning?
480rwhp with an unlocked A4 and the parts you have listed is way too optimistic. But you should be doing much better than 350 if everything is assembled and tuned properly, and you have all the bolt-ons mentioned above (like exhaust/lid).
I didn't see any mention of headers in that mod list. Stock manifolds and/or exhaust will really hold that setup back, and I could definitely see you picking up ~50rwhp over the stock manifolds/cats/exhaust with that setup.
How about an air lid? I assume you have one, but it's not listed. If you happen to be using the stock lid, you're probably leaving about 15rwhp or more on the table there too.
How much faith do you have in your head porter?
Who did your tuning, and did they use a dyno during the tuning?
480rwhp with an unlocked A4 and the parts you have listed is way too optimistic. But you should be doing much better than 350 if everything is assembled and tuned properly, and you have all the bolt-ons mentioned above (like exhaust/lid).
03-17-2012, 11:18 PM
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I have 1.75 headers, k$n, slp lid, no cats, pacesetter y pipe, magna flow muffler. 450 is all you all think I can get out of a 6 liter bored over with 12cc dome pistons, I think it is 11.7:1 compression.
03-17-2012, 11:31 PM
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Oh yes the car is an auto with a pi 3600 stall. Should it be ran on the dyno with the converter locked up or not? What rpm should I redline the ms4, around 7200? And thanks for all of the replies and input. I am new to these cars but I am mechanically inclined.
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03-18-2012, 08:55 AM
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We have a dealership here that tunes. We don't have very many tuners here. I had a bad experience with the one who was suppose to be the best. He had my car for two weeks with no results. The dealership will run your car all day and not just three runs. I don't know if he has ever tuned a car as radical as mine. I think he has just tuned cams. Does anyone think if the motor was built tight I would lose power before I break it in. I have not really ran the car since it has been put together. If the heads were over torqued how could you tell? And thanks for all of the feedback.
03-18-2012, 02:21 PM
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With a forged bottom spin to AT LEAST 6,800 with that cam.
****, I spin to 6,800 and most people I run with spin to 7,000 and thats with stock bottom ends. That cams powerband is 4,000-7,000 give or take. An auto MUST be locked on the dyno in 1:1 when chasing the highest dyno numbers. Don't make a habit out of it though. Single disk aftermarket converters don't appreciate constant 1:1 WOT locks.
BTW, dyno tuning at a Chevy dealer with a "mild tune"? Not sure what to make of that but find a local speed shop and get it aggressively tuned at a performance shops dyno. No decent tuner would set the redline on a forged (minus crank, I know) mill with a big duration cam @ 6,200RPM.
**** my stock redline in the Goat was higher than that with the stock infant duration old man cam. Find a real tuner/shop and get this engine healthy.
****, I spin to 6,800 and most people I run with spin to 7,000 and thats with stock bottom ends. That cams powerband is 4,000-7,000 give or take. An auto MUST be locked on the dyno in 1:1 when chasing the highest dyno numbers. Don't make a habit out of it though. Single disk aftermarket converters don't appreciate constant 1:1 WOT locks.
BTW, dyno tuning at a Chevy dealer with a "mild tune"? Not sure what to make of that but find a local speed shop and get it aggressively tuned at a performance shops dyno. No decent tuner would set the redline on a forged (minus crank, I know) mill with a big duration cam @ 6,200RPM.
**** my stock redline in the Goat was higher than that with the stock infant duration old man cam. Find a real tuner/shop and get this engine healthy.
