LT4 Underdrive Pulley?
Thread Starter
Safety Car
Joined: Jul 1999
Posts: 3,946
Likes: 63
From: Marianna FL
LT4 Underdrive Pulley?
Does anyone make an underdrive pulley or pulleys for an LT4? I looked on March's website and didn't see one listed and the one listed for LT1 Corvettes on Automotive Specialties website says it won't fit an LT4. 
Race Director
Joined: Aug 2003
Posts: 11,043
Likes: 3
From: San Jose Pat Tillman - American Hero
I too believe I've read somewhere that there just aren't UDPs for the LT4...maybe has something to do with the harmonic balancer? I can't remember for sure, but I do recall that there aren't any pulleys.
Racer
Joined: Jul 2002
Posts: 447
Likes: 0
From: Malta Europe
There is not that much need for an under drive crank puley for an LT1 or LT4 engine !!!
A.I.R pump is electric motor driven and the Water pump is camshaft driven so there is the A/C left that when you are at WOT it goes off automaticly and what left to underdrive is the power steering pump and the alternator wich in my opinion it isn`t a good thing to make the alternator turn slower ,unles you buy the Power Amp Alternator pulley !! But if you make the power Amp alternator pulley your back to were you had started because the alternator will turn the same way before you did the crank pulley !!
In my opinon to spend that much $$$ and time to Underdrive only a Power steering pump and the tensioneer is not worth it
Good Luck.
A.I.R pump is electric motor driven and the Water pump is camshaft driven so there is the A/C left that when you are at WOT it goes off automaticly and what left to underdrive is the power steering pump and the alternator wich in my opinion it isn`t a good thing to make the alternator turn slower ,unles you buy the Power Amp Alternator pulley !! But if you make the power Amp alternator pulley your back to were you had started because the alternator will turn the same way before you did the crank pulley !!
In my opinon to spend that much $$$ and time to Underdrive only a Power steering pump and the tensioneer is not worth it
Good Luck.
Melting Slicks
Joined: Sep 2003
Posts: 2,270
Likes: 118
From: N. Babylon NY
I agree you won't see much improvement. However, if you road race, turning the powersteering pump slower is a good thing.
I just did this to my LT1. They gave me the wrong belt so I have not yet ran it.
Steven
I just did this to my LT1. They gave me the wrong belt so I have not yet ran it.
Steven
Thread Starter
Safety Car
Joined: Jul 1999
Posts: 3,946
Likes: 63
From: Marianna FL
Well it is mainly for part throttle driving and the drag the AC puts on the engine. The underdrive pulleys I used on my 88IROC didn't help much other than with the AC on and thats what I'm after for the LT4. I've never had a problem with underdrive pulley's and alternator charging, but I don't spend a lot of time idling either.
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Go here;
http://www.atiperformanceproducts.co...ts/damserp.htm
I run the ATI 6.75 diameter (10% underdrive) in the aluminum model (P/N 917071) W/ aluminum hub (P/N 916094).
http://www.atiperformanceproducts.co...ts/damserp.htm
I run the ATI 6.75 diameter (10% underdrive) in the aluminum model (P/N 917071) W/ aluminum hub (P/N 916094).
