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View Full Version : LSx Under Drive Pulley....Benefits out weigh the risk?


badazz81z28
08-02-2013, 07:17 PM
Thinking about getting an under drive pulley. Its basically the only thing I havent done to my engine. Do you really gain power and ET at the strip? I also heard of charging issues and the pulleys inadequate ability to absorb harmonics. Thoughts?
Z06vet
08-04-2013, 03:39 PM
I run them on both our cars with no issues. Both have LS1s with vintage air. One is 6 speed the other 4L60E. A smaller alt pulley is available if charging is a concern. Not a huge power difference but noticeable. Small gains dont expect a major improvement.
Scott
badazz81z28
08-07-2013, 12:23 PM
I run them on both our cars with no issues. Both have LS1s with vintage air. One is 6 speed the other 4L60E. A smaller alt pulley is available if charging is a concern. Not a huge power difference but noticeable. Small gains dont expect a major improvement.
Scott



Any improvements in trap speed or ET?
rocketrod
08-07-2013, 01:35 PM
Any improvements in trap speed or ET?
I have read you get about a 5rwhp-7rwhp gain....so probably not enough to make a noticeable differenc in mph or ET, but when combined with other mods it adds up.
badazz81z28
08-07-2013, 04:06 PM
I have read you get about a 5rwhp-7rwhp gain....so probably not enough to make a noticeable differenc in mph or ET, but when combined with other mods it adds up.

For a full bolt-on car, this is the only mod I haven't done. If I don't gain any ET or MPH, why get one?
brownz
08-07-2013, 04:41 PM
I have one on my ls1 with vintage air and have no issues. I do have a Katech belt tenisor tho. I dont know what the gain was as I didnt dyno it before. My car is a cam only and made 397 RWHP
badazz81z28
08-07-2013, 04:49 PM
I have one on my ls1 with vintage air and have no issues. I do have a Katech belt tenisor tho. I dont know what the gain was as I didnt dyno it before. My car is a cam only and made 397 RWHP

I have 455 right now...I would like to see a drop in ET of at least a 1/10. But if I don't gain anything....How was the butt dyno before and after?
brownz
08-07-2013, 05:33 PM
I never ran the engine stock so I cant say. I guess all I can say is it wont hurt anything

what your car running in the 1/4?
badazz81z28
08-07-2013, 06:42 PM
I never ran the engine stock so I cant say. I guess all I can say is it wont hurt anything

what your car running in the 1/4?

lol...Not good. I have only raced it at the local 1000ft street drags (really like a street). My best is [email protected]
JMitch19
08-08-2013, 11:40 AM
You will be better served looking for your answer on LS1tech.com. You won't find to many people drag racing their PT cars.

Just for ****s and giggles I did the math and 11.04 @ 1000ft = about 12.9-13.1 in a 1/4 mile depending on how well the car back halfs. My 420rwhp Camaro went 12.4 @ 114 in the quarter with an SLP underdrive pulley. I never ran my car with the stock pulley. If you want a dampener with better harmonic dampening qualities look at what ATI has to offer. I believe they only offer a 10% reduction vs. SLP at 25%.

https://static1.pt-content.com/images/pt/2013/08/1240slip-1.jpg (http://s470.photobucket.com/user/jrmitch19/media/1968%20Camaro/1240slip.jpg.html)
badazz81z28
08-14-2013, 11:28 AM
I'm just looking to squeeze more power out of my engine. My car is a lot faster than the ETs tell. I have 455 ponies to the tire now, I know I'm capable of mid 11s in the 1/4. I really built my car for auto cross, but drag racing is fun so I do that too.

Here's a video of me racing a 5th Gen SS LS3.

https://www.youtube.com/watch?v=x77mrfq2F7Q