Thinking about getting an underdrive pulley for my 95 T/A- anybody install one on an Lt1 and notice a difference? Anywhere near the 10-15 Hp most companies claim? just wondering because the Lt1's serpentine isnt driving a water pump like normal cars
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You are very observant....
The U/D pulley will not get you anywhere near 10-15HP on an LT1.
Here's a dyno test that netted a gain of 0.7 peak HP (yes, that would be 7/10ths of one HP). Average gains were better at about 4HP, and torque was improved. Based on my experience, that's probably all you would see. I couldn't measure it.
There are also a few "varieties" of U/D pulleys. One is a pulley that sandwiches between your stock damper and the hub, obviously adding rotating mass. Another is a total replacement for the stock damper. These are made by ASP, and in effect are both a damper and a U/D pulley.
Then there is the issue of alternator performance. I had the ASP 25% U/D crank pulley/damper, and 15% U/D alternator pulley. At a stop light, with any accessories on, the volt meter goes into the red, unless you rev the engine. You can get a set from March called the "power and amp" sereies, which is a U/D crank pulley, and O/D alternator pulley to compensate for cars with heavy electrical loads (and of course, give up a little of the already miniscule savings).
Personally, I wouldn't recommend them, but that's just one opinion.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor -
I'd agree with Fred.
I had one on a 95 Z... it was worthless. No difference in the 1/4 and no SOTP improvement.
Save the $$ and put it twards something more worthwhile.Comment
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i also agree with fred. waste of money. in the old days...they were a "hot item"..back in the 60's..... now......
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sold: 97 Firehawk, 97 Comp T/A, 2005 GTO, 2008 Solstice GXP turbo.Comment
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well i'm glad i read this post ^.^ i was looking into one but now i'm forgeting about it. how about those pulies that are the same size but have that harmonic dampier? (spelling) its supposedto help your engine in high revs. is that true or another hoax?1997 Camaro, Z-28, 5.7, Manual 6, K&N cold air intake, custom ram air scoop, ported MAF, Resonator plug, air foil, 160 thermostat, hypertech power programer 3, 3 inch cat-back exhaust, strut tower brace, K&N valve breather, centerforce dual friction clutch, slp short throw shifter, TNL short stick, O2 simulators, Next mod will be 1.6 rockers, pushrods, and springs. any reccomendations?Comment
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I took mine off after running my batter down several times. Not worth the pain. I dunno about hp on the dyno but I felt a sop difference in that it seemed to rev faster. Just spend the money on a go fast part.Comment
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