Underdrive Pulleys Pro/Cons

[2k05gt]

I have the Steeda Underdrive pulleys and No speed change to the Water pump the Crank pulley is 25% smaller and the water pump pulley is 25% larger the Alternator, and power steering are reduced to save you a little on drag from those items. I have the AVID-D1 Radio and I can minitor my voltage and I have not noticed a change. The Alternator is designed to generate at least 13 volts at 500rpm and up to 35 volts at 6000 rpm, the voltage regulator keeps the charging volts between 12.9 - 13.8 so no problems.

 

[marcspaz]

There was a caviat there:

"NO effective water pump impeller speed change"

Makes sense to me. However, the sky is blue in my world.

Blue! You need better drugs...LOL

 

[Newbreedgt05]

Is there a reason why the Saleen setup has three pulleys?

 

[SoundGuyDave]

---NOTICE OF RETRACTION---

Please note that I corrected my earlier cranial-rectal inversion in post number 15 of this thread... That said:

65SOHC: you got me dead to rights, although you missed my retraction, so one demerit for you!

Gig: When I screw up, call me on it!! No demerits, but six asshole points!

Marc (OMG that is too funny!!!) You're absolutely right! And yes, I think Stanley needs better drugs too!

2K05GT-- Think it through. Smaller crank pulley means less belt travel per pulley rev, thus the underdrive. With the water pump pulley being larger, that means that it will take more belt travel to create a revolution. The net result is that the water pump is spinning seriously slower than stock. Think of it this way: If you want to increase boost with a blower, you first run smaller and smaller blower pulleys, so that a given amount of belt travel will result in more input shaft revolutions. OR you increase the diameter of the crank pulley, so that there is more belt travel per driven revolution. NO asshole points for you!!

Seriously, guys, I screwed the pooch and freely admit to it. I was in a rush, thinking of other things (work related, unfortunately) and just got my head twisted around with which was driving and which was driven. My bad. Now, can't we all just get along???

 

[billy_the_kid]

Thanks for everyones response. A mechanic told me that under driving your accessories is acutally bad for them in the long run. I wasn't sure, so thanks for the info.

 

[Charlie Sheen]

Thanks for everyones response. A mechanic told me that under driving your accessories is acutally bad for them in the long run. I wasn't sure, so thanks for the info.

From a mechanical standpoint, the accessories are being used less. Why would that be bad for them?

 

[marcspaz]

---NOTICE OF RETRACTION---

LOL, No harm no fowl! This is a tough crowd.

From a mechanical standpoint, the accessories are being used less. Why would that be bad for them?

+1...that tech is a tard.

 

[2k05gt]

---NOTICE OF RETRACTION---

2K05GT-- Think it through. Smaller crank pulley means less belt travel per pulley rev, thus the underdrive. With the water pump pulley being larger, that means that it will take more belt travel to create a revolution. The net result is that the water pump is spinning seriously slower than stock. Think of it this way: If you want to increase boost with a blower, you first run smaller and smaller blower pulleys, so that a given amount of belt travel will result in more input shaft revolutions. OR you increase the diameter of the crank pulley, so that there is more belt travel per driven

Sorry Brain Fart, It is smaller by 25% and so is the crank pulley,
thats why you have to cut or replace the water pump bolt so the Pulley will fit. Again sorry about that.

Thanks for everyones response. A mechanic told me that under driving your accessories is acutally bad for them in the long run. I wasn't sure, so thanks for the info.

The only problem you may run into with UDP's is if you have a high powered stereo with multiple amps then I think there would be a charging issue.
other than that, like Mister Roper stated, there moving slower why would that damage them

 

[SoundGuyDave]

Sorry, Brain Fart..

No worries, me too... must be the phase of the moon or something.

The only problem you may run into with UDP's is if you have a high powered stereo with multiple amps then I think there would be a charging issue.
other than that, like Mister Roper stated, there moving slower why would that damage them

The high-powered stereo thing has it's own set of mods and supporting mods, and the guys that are running those kinds of rigs happily accept the weight penalty, and don't worry about the extra couple of HP an underdrive will give you, so... If you're heading that way, IIRC Dustin upgraded to a 200A aftermarket alternator with good results.

 

[Forge]

Dave -

I remeber reading about it, how did the alternator turn out? i know he had some issues at first, but lost track of the post after that.

 

[marcspaz]

I'm trying to get my car lighter. I can't see putting 100-200 lbs of extra weight in a car I plan on racing.

Sound systems can be a pain in the ass when it comes to power issues. My first business was a home & car audio and security company. We had a few custom projects that involved several batteries, a couple of 1 farad Caps, and 2 x 190 amp alts...all to get glass-breaking, ear-bleeding 134 SPL's with less than .01% of noise or distortion at a massive 2400+ watts RMS total system power. Even with all that extra B+, the headlights still dimmed with the beat...LOL

 

[SoundGuyDave]

Forge: As far as I know, it all turned out just fine.. Dustindu4 is his handle. I know he blamed his problems on the UDP setup, but as far as I've seen, he's the only one that had any issues.

Marc: Yeah, I've done a few of those... These days the sound systems I play with need 150A 3-phase 208V just to power up. Usually measured in the 100kW range too.

 

[MikeVistaBlue06]

The only thing I will add to this is, if you let your car sit a couple of weeks and the battery dies, then I would not be inclined to do it. That happens if you have the Shaker 1000 system in your car.

I have to keep a battery tender on mine regardless of when I turn the radio on or off before I cut the ignition key. I still have the stock POS battery which basically has the capacity of a gnat's ass, and in fact I give it 100 asshole points right off the bat!

You may want to look at a better battery (Optima) if you decide to do this and then have issues with the battery losing charge.

I have a Saleen so I am using the pulleys they provided. Also, here in Dallas when it hits 100°+ degrees, I want my AC pulley spinning as fast as it can!

Hope this helps.

Mike

 

[MikeVistaBlue06]

Sound systems can be a pain in the ass when it comes to power issues.

Yes they can be! For the power you describe, you probably need an extra battery with 2 gauge cables running to just it to keep it charged, and then several 1F caps on the hot side of the amps for when the bass hits!

Mike

 

[marcspaz]

Yeah, I've done a few of those... These days the sound systems I play with need 150A 3-phase 208V just to power up. Usually measured in the 100kW range too.

Sweet! You must be helping put on some big shows. Thats like, convention center type stuff...

Yes they can be! For the power you describe, you probably need an extra battery with 2 gauge cables running to just it to keep it charged, and then several 1F caps on the hot side of the amps for when the bass hits!

Mike

Oh yea. My favorite part is the customer in sticker shock. I can't tell you how many people complained because I charged them $215 for 14 feet of copper. They think that shit is free...LOL After I show them the welded terminals they tend to relax a little.

 

[1550GT]

I installed the Steeda UDP's in my GT and haven't had any problems with it. Mine is not a daily driver and it sits in the garage for four or five days and up to two weeks before I drive it at times. I also have the Shaker 1000. I have a manual shift and noticed that the engine revs. quicker with the UDP's than before. Gas mileage should increase a little due to the reduced drag on the motor, although I don't know that for sure because I installed a tune in the car the day after I did the pulleys. I am getting better gas mileage as a result of the two installations. I ordered both from Brenspeed.

 

[marcspaz]

...I have the Steeda UDP's. The only issue I have is when it rains, my belt slips a little for the first 120 seconds the car is on. A shade longer if the AC is on right away. I am going to replace the belt with a shorter one...

very strange, let us know when you ge tthe new belt if it helps.

Well, for those of you who asked for an update, I replaced the belt. Stock was a 6 rib, 27/32x102. I replaced it with a 6 rib 27/32x101.5 (101 was too small). The weather has warmed up and it rained a few times. The replacement belt seems to have resolved the issue.

 

[GRAYPNY]

I just installed underdrive pulleys and cmcv delete plates last weekend and picked up 2 mpg. That in itself is a reason to install them.

 

[Blackmagic1]

I have the Steeda pulleys too. No probs. Crank pulley is alot lighter than factory one also.