Gears Question, Please Help !!!!!!!
Thread Starter
Instructor
Joined: Sep 2006
Posts: 118
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Gears Question, Please Help !!!!!!!
had 2:73 gears on my 93 Camaro Z28 6 speed manual tranny. I dynoed at 278.00 rwhp with every bolt on. I dynoed a second time with those same gears again at the same numbers pretty much. I changed to 3:42 gears and only that mod i dynoed lower to 266.00 rwhp lost 12rwhp. Ive heard from several people that you lose rwhp on the dyno due to gears but why ? and do you really lose rwhp ? why cant the dyno compensate for the gear swap and give you correct rwhp numbers. Can anyone help please ! ! !
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
other variances can also affect your drno results.
As Kalway mentioned, was it the same dyno?
temperture conditions, hotter, colder, more or less humidity all affect tuning and how well the engine runs.
Even the calibration of the same dyno equipment can vary.
As Kalway mentioned, was it the same dyno?
temperture conditions, hotter, colder, more or less humidity all affect tuning and how well the engine runs.
Even the calibration of the same dyno equipment can vary.
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Being that you've got an LT1 Camaro I'd suggest asking the guys on the C4 section. One thing that I'd GUESS might do something to that is that since your ECM is a learning computer you might want to reset it by pulling the fuse for a minute and putting it back in. It will default back to its original maps and such then.
You may also need new plugs, wires, and a good fuel system flush. Fuel injectors can get clogged and plugs and wires do wear out over time.
You may also need new plugs, wires, and a good fuel system flush. Fuel injectors can get clogged and plugs and wires do wear out over time.
Safety Car
Joined: Oct 2004
Posts: 3,926
Likes: 739
From: Youngstown Ohio
Originally Posted by Kalway
Being that you've got an LT1 Camaro I'd suggest asking the guys on the C4 section. One thing that I'd GUESS might do something to that is that since your ECM is a learning computer you might want to reset it by pulling the fuse for a minute and putting it back in. It will default back to its original maps and such then.
You may also need new plugs, wires, and a good fuel system flush. Fuel injectors can get clogged and plugs and wires do wear out over time.
You may also need new plugs, wires, and a good fuel system flush. Fuel injectors can get clogged and plugs and wires do wear out over time.
After talking with the dyno operator, and verifing this through personal experience, a rear gear change alone has no effect on RWHP. It doesn't matter what the ratio is.
Instructor
Joined: Sep 2005
Posts: 241
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From: St Louis Missouri
As I read, you have two questions, why would gearing affect RWHP, and should the dyno compensate for gears.
Gearing will affect RWHP by friction losses. If you have more teeth meshing then there will be a greater energy loss due to friction and heat. 12HP seems excessive, it's usually small.
Should the dyno compensate for gearing? No. The dyno reads the RWHP, any numbers to get the flywheel HP contain speculation.
Gearing will affect RWHP by friction losses. If you have more teeth meshing then there will be a greater energy loss due to friction and heat. 12HP seems excessive, it's usually small.
Should the dyno compensate for gearing? No. The dyno reads the RWHP, any numbers to get the flywheel HP contain speculation.
