kokingSS

iTrader: (2)

so basically i am looking to get an underdrive pulley, but i was wondering what you acomplished with it. i know that it frees up rotational mass, thus allowing you to rev faster. but have you noticed a diffrence with yours? is it a worth while investment? any info would be greatly appreciated.

Dustin

EDIT: i just got my pulley from SDPC and i wanted to know whether or not it has helped anyones E.T. and if it has how much?

LS1crazy01

iTrader: (14)

You know I was un sure before I bought mine but im real glad I did. I have and SLP u/d crank pulley. It does make a noticable difference. I would say its worth the extra hp for the money. It does rev faster and you really feel the power up top more. If your going to install it your self I suggest you search because some people have problems when not using the proper tools.

kokingSS

iTrader: (2)

i didnt think it gained h/p.

'Trust'

iTrader: (24)

My gains with an UD pulley and ported TB were really good. 10 RWHP, 21 RWTQ peak, and close to 35 RWTQ under the curve.

teke184

iTrader: (5)

you said that it "frees up rotational mass"

but actually it really jsut spins the accessories slower, which means the engine has to use less power to do so..which translates to more power at the crank.

the rotational mass isn't so much removed...but spun slower. and that "mass" is that of the accessories...not so much the crank pulley itself.

i can't say i noticed much power increase, but than again i installed a bunch of mods in the first month of owning the car...so i was still getting use to the power anyway.

but i DID seem to rev faster, so i'm sure it helped. for the 5-10hp you'll see...i say its not a bad mod for a bolt on car, or for those just learning how to work on their car.

TXZ28LS1

iTrader: (5)

damn 'TRUST'!! those are some stout numbers man. i hope i make the same when i throw my pulley in as well.

SladeX

By slowing down your accessories, you stand to preserve them longer. Does your AC need to spin up THAT much to cool down your car? Does your water pump need to flow that much?

Truth be told, since the alternator, water pump,PS pump and a/c are identical between manual and auto cars, and auto cars run 600 rpm in gear as opposed to the m6's 800, the UD pulley puts the system right in line with an auto car. 25% of 800 brings down to 600rpm. Keep in mind that an auto car NEEDS to remove the heat from the transmission too.

I've had no issues "freezing" the interior of my car with the A/C with an underpulley nor have I had any power issues or cooling issues with the car.

Scoggin Dickey

iTrader: (34)

It's a great investment. More HP and better fuel mileage together with one mod. You will definitely notice that your cars revs more freely.

Shoot me a pm and I'll make you a great deal on in a pulley, we keep them in stock and ship the same day

Assman

iTrader: (2)

Nice little mod, cheap too. I have a SLP and i'm getting better milage even after the 4.11's. I did it the same time as my rear so I couldn't tell you what it did for me. As for rotational mass, it weighs just as much if not a bit more than the stock pulley, surprised me a bit.

LS1crazy01

iTrader: (14)

Dude I wieghd my stock pulley and it came in at 11.5 pounds. Never put the SLP on the scale but it was alot lighter and a smaller diameter. When I tried to put the stock one in the box that the SLP one was in it wouldnt fit.

foreverzero

iTrader: (5)

how hard is the install? could i do it in 6 hours?

Scoggin Dickey

iTrader: (34)

You should be able to do it in FAR less than that. I can do it in 30 minutes

jrob56

iTrader: (39)

so would u have any problems with the accessories when installing one on an auto car?

Bad Blue WS6

iTrader: (41)

30 minuites?!?

Assman

iTrader: (2)

It is a lot smaller, but I had one in each hand and it was no lighter. That's what suprised me. Does anyone have the weight of a SLP pulley?

Scoggin Dickey

iTrader: (34)

Powerbond is 10.7 pounds. It isn't the actual weight that makes most of the difference, it's the diameter. Even a little weight when referring to rotational weight is significant though

fbodyman1026

iTrader: (11)

so if your planning to install U/D pulley to need to remove your heat??

waldershrek

iTrader: (1)

^^^No he means the transmission is cooled through lines going through the radiator. However an U/D pulley isn't going to affect that really. If you are concerned about transmission cooling invest in a transmission cooler.

SladeX

If you really are concerned with power issues on an auto car, you can get an underpulley with a overdriven alternator pulley.

As for cooling the transmission, the lines go through the radiator too. Most people that are considering an underpulley also run other mods too and I think for an auto a transmission cooler should be on the list as the mods. I picked one up from a local parts store on the cheap for my previous Camaro. I'm sure autozone will have some kind of kit that will work out fine.

landonew

Actually, you are incorrect. Rotational mass is equivelent to rotational resitence. by placing a load on the pulley you are increasing the rotational resistance, thus increasing the net rotational mass. By spinning the accesories at a slower speed their is less parasitic loss due to their operation because there is less rotating mass.