Underdrive pulleys

[XAlliedYouthX]

WIth an installed underdrive pulley setup is it just a static performance gain or is it effected by other engine modifications?

[Xidion]

I installed the UD crank pully and got faster throttle responce. With that and my CAI i have higher RPM accell.

[pontiacelite]

do you have a system that draws a lot of power. If you do did the lightened pulley mess with the way your systems sounds at all?

[Jigga9JayZ]

the UD pulley shouldnt effect your alternator/system or enough to matter anyway....now getting a new alt pulley is a different story

[Xidion]

The only way your alt will be effected is if you put on the AEM pully or get a full pully kit. The UD oully will not effect the alt at all.

[Jigga9JayZ]

Originally posted by Xidion
The only way your alt will be effected is if you put on the AEM pully or get a full pully kit. The UD oully will not effect the alt at all.


didnt i just say that....:roll2: ....lol

[tdub4life]

Whats the best place to buy an underdrive pulley setup from? I'm thinking about setting aside some cash for one.

[XAlliedYouthX]

I ment the fully underdrive pulley setup. Like the set that customcargrills.com sells.

[Xidion]

Like i said if you get a full set yes your Alt out put will be low.

[XAlliedYouthX]

Originally posted by XAlliedYouthX
WIth an installed underdrive pulley setup is it just a static performance gain or is it effected by other engine modifications?

Still looking for an answer

[Pte Socks]

Isnt it best to get just a lightened pulley and not a UD? I remember reading something somewhere on this topic.

[XAlliedYouthX]

I just know that it's lighter and smaller. And to counteract the alternator issue u can open the TB a little more at idle

[Jigga9JayZ]

well i have both....unorx ud pulley and aem alt pulley....it deff accelerates faster from a stop...and my power is deff drained, whenever i pop the clutch in and it is at idle my headlights dim pretty low and this is with my stereo on or off....i always turn tit off or way low if i'm gonna be sitting awhile...stop lights, etc....then i most often keep it revved to just over 1k and my lights act better.

if you can get a deal on the pulleys i reccommend them...not sure about both new and full price....i got both mine for 120

[Azrael]

Fastfowdperformance.com sells a UDP that only lowers the alt's output by 0.3v with a nice boost in performance. As far as it's gains with future mods it's hard to say. Any lowering of resistance on the crankshafts rotation can only be good for performance. To a point anyways.

[XAlliedYouthX]

Is there even a point to the alternator pulleys??

[Colin]

Originally posted by XAlliedYouthX
Is there even a point to the alternator pulleys?? Not worth worrying about unless it's a race car . Don't bother if you have a mega watt sound system .:roll2:

[XAlliedYouthX]

What is the point though. I'm curious.

[Colin]

Originally posted by Azrael
Any lowering of resistance on the crankshafts rotation can only be good for performance. ^ It takes power to turn that alt , if you reduce the speed at which it's driven you save energy which will free up power .

[XAlliedYouthX]

Gotcha

[urweak]

I wouldnt bother with the UR pulley, ive wanted it for awhile, but the thing about it, its not balance like the stock pulley. I know a few import guys that have broken motors b.c of this problem. I would go with the 2.3 HO pulley instead.

[Xidion]

i have an under drive crank and have had no problems with it. I get better gas miles and faster throttle responce.

[voyager]

a smaller crankshaft pulley most definately affects the alternator. the alternator will not roate as far for each roation of the crankshaft.

i've had the FFP pulley for quite a while with no problems in either cooling or voltage. there's a small drain; my dash lights dim a little at idle but it's nothin major. there's a noticeable gain in throttle response and acceleration, especially over 3000rpms. i don't see how other mods would complement an UDP directly. the 3100/3400 crankshaft is internally balanced - no worries there. the pulley is an harmonic dampner - not a balancer.

i'm a big fan of the UDP. at 8-10hp for ~ $120 it's one of the best 'bang for your buck' mods you can do. i know some people don't agree with me on this, but hey that's my experience.

i don't suggest you mess with the TB plate - it won't counteract the alternator drain; all it'll do is screw up your idle and make you run lean or rich, depending on the temperment of your sensors. a smaller alternator pulley would counteract the smaller crank pulley's drain - this is geometry, not combustion we're talking about.

[XAlliedYouthX]

Originally posted by voyager
i don't suggest you mess with the TB plate - it won't counteract the alternator drain; all it'll do is screw up your idle and make you run lean or rich, depending on the temperment of your sensors. a smaller alternator pulley would counteract the smaller crank pulley's drain - this is geometry, not combustion we're talking about.

If you have more cobustion and the crank spinning faster as if the car was moving then to me it seems that it would supply that extra charge to the alt. pulley to keep it charged like normal.

[voyager]

if you want to open the TB plate, just use your gas pedal. don't try to adjust it. if you just adjust the plate, you're letting more air in, not more gas. at idle, the ECU thinks it has x amount of air and provides y amount of gasfor the proper x/y air-fuel ratio. if you change the amount of air coming in, you still have y amount of gas at idle, resulting in a lean or rich mixture.

really unless you have a mammoth stereo amp or alot of neons/12v accessories, the voltage drain isn't going to make a difference in performance.

[XAlliedYouthX]

Originally posted by voyager
if you want to open the TB plate, just use your gas pedal. don't try to adjust it. if you just adjust the plate, you're letting more air in, not more gas. at idle, the ECU thinks it has x amount of air and provides y amount of gasfor the proper x/y air-fuel ratio. if you change the amount of air coming in, you still have y amount of gas at idle, resulting in a lean or rich mixture.

really unless you have a mammoth stereo amp or alot of neons/12v accessories, the voltage drain isn't going to make a difference in performance.

But if that little bit more air is coming in isn't it able to adjust itself by adding in that extra fuel? Cause when you hit the pedal all it is doing is opening the TB anyway, right?

[voyager]

the 02, MAF and IAT sensors aren't between the TB and the plenum; they're on the other side of the TB. the car adjusts the TB plate according to the air coming towards the TB, not the air passing through it.

[awallsgt]

What can you expect to see if the udpulley is your only mod are we talking 1-5hp or possibly 5-10hp?

[Azrael]

Originally posted by awallsgt
What can you expect to see if the udpulley is your only mod are we talking 1-5hp or possibly 5-10hp? Dyno (http://fastfwdperformance.com/uddyno.htm)

Unless the differences between the 3.1 and berreta drivetrain with ours are extreme we should see a similar increase percentage-wise. So roughly 5-10 HP. You can also expect to see better fuel mileage and in some cases lower coolant temp.

After some thinking I'm believing that the gains from a UDP would be mostly static. The devices that use power from the crankshaft draw a static amount of energy and a UDP only reduces the amount of that power transferred. It doesn't exactly reduce the restriction of air going in and exhaust coming out.

[FORTEEN3GT]

Originally posted by Azrael
Fastfowdperformance.com sells a UDP that only lowers the alt's output by 0.3v with a nice boost in performance. As far as it's gains with future mods it's hard to say. Any lowering of resistance on the crankshafts rotation can only be good for performance. To a point anyways.

Forum Junkeys only please (newbie's dont respond):

does the fast forward performance pulley slip at all? i am concerned that it will slip while sitting at 6k rpm and shifting into 2nd or 3rd??

what does the surface look like? is it smooth?

thanks

[voyager]

it doesn't slip; the surface is ribbed to accomodate the serpentine belt. it is of high quality.

=)

[Xidion]

They wont slip the should give you a new belt or belt number and they are higher quality than stock is. You will be very happy with one.

[1992grandam]

i had a 2.3 H.O pulley on my old 2.4......i loved it and im planning on buying a UDP and alt pulley for my 3.1 as soo as i get the money

[voyager]

here is a quick pic of the pulley so you can see the ribs. there is a better chance of the belt slipping on the water pump than the crankshaft pulley.

i don't see why this is a hard decision.. i love my pulley!