dyno day
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From: Fredericksburg Va.
dyno day So today I went and had my car dynotuned at a very reputable shop. At the end of the 4th pull, I heard the cars rpm suddenly jump through the roof. I thought that the cars transmission went from being in gear to neutral. The guy who did the tune said that the car downshifted from third to second on its own. This event led to the car being declared undriveable (cylinder misfire) and was towed home (50 miles). The process of the tearing down the motor down starts tomorrow. I asked the tuner to send me the data from the pulls and everything he had from the fatal pull but I have not received any information to date. Any thoughts, input or previous experience would be greatly appreciated.
car was dyno'd in tap shift right? i dont see how it could down shift on its own in tap mode at wot.
if the trans did down shift then the rev limiter and fuel cut off should have engaged. was this tuned out? i have spun to 6800 many of times witout problems.
if the trans did down shift then the rev limiter and fuel cut off should have engaged. was this tuned out? i have spun to 6800 many of times witout problems.
if your missfiring do a compression check on that cylinder, followed by a leak down test. maybe the engine floated a valve and it hit the piston and bent, or put a hole in the piston. make sure the rockers are adjusted. i had one back way off and had a miss fire and noisy lifter.
i still wanna know what you dyno'd so please share.
i still wanna know what you dyno'd so please share.
Thread Starter
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From: Fredericksburg Va.
update; bent valves!!!
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Thread Starter
TECH Apprentice
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From: Fredericksburg Va.
i would expect a lot more form your set up. its pretty close to my build. 290 hp is good for about 105-106 in the 1/4.
if the valves are bent i would make the shop pay for the bill, or try. great time for a ls6 intake and new cnc heads! hopefully the pistons arent damaged.
im still excited for you and i know you engine has a lot more in it.
if the valves are bent i would make the shop pay for the bill, or try. great time for a ls6 intake and new cnc heads! hopefully the pistons arent damaged.
im still excited for you and i know you engine has a lot more in it.
So; I have been posting with the smart phone today..
Now I am at home, and have looked at the e-mail. I don't know hp tuner stuff but from what I can tell.. everything looks ok. I am no tuner by any means.
Post those logs in the tuning section and try to get JCM5 to review them for you, so PM him your logs.
I still don't understand how your trans downshifted. I hope the trans didn't fail too.
Try to remain calm, and find an answer. Easier said then done, as I have been in your shoes too! I blew a lifter last year and then had another fail so I decided to do it right and went with best.. of the best.
If the valves are bent/push rods ( I bet they are!) then look into some cylinder head upgrades and definitely upgrade your valvetrain. Your lucky you didn't throw a rod if the motor went past 7000rpm! Tuner and shop owner should have an answer.
I'm super sorry this had to happen to you. Please keep us posted. I wouldn't worry to much about the numbers but I think your 2.5" exhaust is costing some power. We should have 3.25-3.5" single into dual 2.5" Also, the LS1 intake is a litte restrictive above 5500.
I'm pretty sure you have another 30whp learking around with a few upgrades and tuning.
Never dyno a hot LS4! Ice the intake and let it cool way down before making pulls. If looking for numbers.
Now I am at home, and have looked at the e-mail. I don't know hp tuner stuff but from what I can tell.. everything looks ok. I am no tuner by any means.
Post those logs in the tuning section and try to get JCM5 to review them for you, so PM him your logs.
I still don't understand how your trans downshifted. I hope the trans didn't fail too.
Try to remain calm, and find an answer. Easier said then done, as I have been in your shoes too! I blew a lifter last year and then had another fail so I decided to do it right and went with best.. of the best.
If the valves are bent/push rods ( I bet they are!) then look into some cylinder head upgrades and definitely upgrade your valvetrain. Your lucky you didn't throw a rod if the motor went past 7000rpm! Tuner and shop owner should have an answer.
I'm super sorry this had to happen to you. Please keep us posted. I wouldn't worry to much about the numbers but I think your 2.5" exhaust is costing some power. We should have 3.25-3.5" single into dual 2.5" Also, the LS1 intake is a litte restrictive above 5500.
I'm pretty sure you have another 30whp learking around with a few upgrades and tuning.
Never dyno a hot LS4! Ice the intake and let it cool way down before making pulls. If looking for numbers.
this isnt a honda motor. got damn 