UNDERDRIVE PULLEYS
4th Gear Member
Joined: Apr 2005
Posts: 1,065
From: LI, NY
RE: UNDERDRIVE PULLEYS
The UDPs do slow down your alternator but it only affects it's output at idle. The output curve on an alternator is not linear, it tops out at about 1000-1200 RPM. What that means is that with the new pulleys, you would have top operate at 1250 RPMs to put out the same power as with the stock pulleys. After 1250 RPMs, the output of the alternator is the same with the old or the new pulleys.
The net effect is that unles you plan to operate all of your electrical devices at idle, having a set of UDP poulleys is not going to affect the operation of your electrical system at all. So go ahead and add the UDPs if you think you can benefit from the extra 10 HP. The difference is noticeable immediately.
The installation is not difficult if you ha the right tools. There are a few things to watch out for. Many say that you need to remove the fan showd and fan for better clearance but I've found that its unnecesary if you use a 4" stubby impact wrench. Sears sells them.
I wrote up the entire procedure and posted it here.
http://www.cherod.com/mustang/HowTo/Pulleys.htm
The net effect is that unles you plan to operate all of your electrical devices at idle, having a set of UDP poulleys is not going to affect the operation of your electrical system at all. So go ahead and add the UDPs if you think you can benefit from the extra 10 HP. The difference is noticeable immediately.
The installation is not difficult if you ha the right tools. There are a few things to watch out for. Many say that you need to remove the fan showd and fan for better clearance but I've found that its unnecesary if you use a 4" stubby impact wrench. Sears sells them.
I wrote up the entire procedure and posted it here.
http://www.cherod.com/mustang/HowTo/Pulleys.htm
s197 Junkie
Joined: Sep 2006
Posts: 16,088
From: IN
4th Gear Member
Joined: Nov 2005
Posts: 1,249
From: Northern VA
RE: UNDERDRIVE PULLEYS
ORIGINAL: zesty
steeda underdrive pullies really give you about 10 hp?
steeda underdrive pullies really give you about 10 hp?
BrenspeedClaims 10hp
Mustang Monthly claims 11hp
ORIGINAL: 07GTEddy
2K05gt,
I like the sig you have. Take a lot of time to make it?
2K05gt,
I like the sig you have. Take a lot of time to make it?
2nd Gear Member
Joined: Feb 2007
Posts: 268
From:
RE: UNDERDRIVE PULLEYS
ORIGINAL: 2k05gt
they are good for an gain of about 10 HP and a bit better MPG increase. less drag on the engine.
Do not install UDP if you plan on a Huge Audio System with Amps and stuff. also if you have the shaker 1000 system it might not be a good idea, other than that sure go for it, I love mine
they are good for an gain of about 10 HP and a bit better MPG increase. less drag on the engine.
Do not install UDP if you plan on a Huge Audio System with Amps and stuff. also if you have the shaker 1000 system it might not be a good idea, other than that sure go for it, I love mine
4th Gear Member
Joined: Nov 2005
Posts: 1,249
From: Northern VA
RE: UNDERDRIVE PULLEYS
ORIGINAL: Foose12
Why? I wanted to do UDP's but plan on a lil extra boom in the trunk..
ORIGINAL: 2k05gt
they are good for an gain of about 10 HP and a bit better MPG increase. less drag on the engine.
Do not install UDP if you plan on a Huge Audio System with Amps and stuff. also if you have the shaker 1000 system it might not be a good idea, other than that sure go for it, I love mine
they are good for an gain of about 10 HP and a bit better MPG increase. less drag on the engine.
Do not install UDP if you plan on a Huge Audio System with Amps and stuff. also if you have the shaker 1000 system it might not be a good idea, other than that sure go for it, I love mine
read odiaz comment
ORIGINAL: odiaz
The UDPs do slow down your alternator but it only affects it's output at idle. The output curve on an alternator is not linear, it tops out at about 1000-1200 RPM. What that means is that with the new pulleys, you would have top operate at 1250 RPMs to put out the same power as with the stock pulleys. After 1250 RPMs, the output of the alternator is the same with the old or the new pulleys.
The net effect is that unles you plan to operate all of your electrical devices at idle, having a set of UDP poulleys is not going to affect the operation of your electrical system at all. So go ahead and add the UDPs if you think you can benefit from the extra 10 HP. The difference is noticeable immediately.
The installation is not difficult if you ha the right tools. There are a few things to watch out for. Many say that you need to remove the fan showd and fan for better clearance but I've found that its unnecesary if you use a 4" stubby impact wrench. Sears sells them.
I wrote up the entire procedure and posted it here.
http://www.cherod.com/mustang/HowTo/Pulleys.htm
The UDPs do slow down your alternator but it only affects it's output at idle. The output curve on an alternator is not linear, it tops out at about 1000-1200 RPM. What that means is that with the new pulleys, you would have top operate at 1250 RPMs to put out the same power as with the stock pulleys. After 1250 RPMs, the output of the alternator is the same with the old or the new pulleys.
The net effect is that unles you plan to operate all of your electrical devices at idle, having a set of UDP poulleys is not going to affect the operation of your electrical system at all. So go ahead and add the UDPs if you think you can benefit from the extra 10 HP. The difference is noticeable immediately.
The installation is not difficult if you ha the right tools. There are a few things to watch out for. Many say that you need to remove the fan showd and fan for better clearance but I've found that its unnecesary if you use a 4" stubby impact wrench. Sears sells them.
I wrote up the entire procedure and posted it here.
http://www.cherod.com/mustang/HowTo/Pulleys.htm
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