Under Drive Pullies
Launching!
Joined: Nov 2007
Posts: 271
Likes: 0
From: Moore Oklahoma
WD
When my car was stock with a flowmaster replacement muffler. I put a under drive crank pulley-balancer on mine and picked up almost 2 full tenth's on the average in the 1/8 mile . At the time I had my car at the track every time they opened the gates.My car was an auto w/out a stall and it seemed like it pulled alot harder down low. My opinion it is the best bang for the buck you will ever put on an auto car.Next to a cold air kit.
BTW with over 50,000 miles of every day driving w/ the pulley I never had any charging issues.
BTW with over 50,000 miles of every day driving w/ the pulley I never had any charging issues.
actually a gti(i think thats a little better 
) sorry i am not a pro drag racer like you rippin off 13.3 in STOCK lt1. must be nice running with ls1's in a stock lt1. but you saying under drive pulleys are a "best bang for you buck" explains alot.
) sorry i am not a pro drag racer like you rippin off 13.3 in STOCK lt1. must be nice running with ls1's in a stock lt1. but you saying under drive pulleys are a "best bang for you buck" explains alot. 
Teching In
Joined: Oct 2004
Posts: 32
Likes: 0
From: San Diego
I have to agree with The engineer, when i changed mine like 8yrs ago i noticed a big diffrence it reved quicker but also accelerated quicker and i never had a charging issue. I dont remember what brand I baught but it bolted on to the back of the stock crank/balancer. but when i did it i put in a C.A.I, clutch, eaton posi with 3.73's and full exhaust headers back so it might of been the combination of the stuff...
Maybe you could give some insight with your extensive experiance. Tell me what other bolt on gives you more power at the track besides a cold air kit for the money.Not saying they are the best bolt-on but you cant beat the gain ,and it is one of the cheapest bolt-ons.
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Like I stated... I felt a difference by far!
That doesn't mean everybody will tell a difference, but I did.
Hell every car is different. I can't even believe you guys' are argueing over a UD Pulley Kit!
Best bang for the Buck is nitrous and everybody knows that. He just simply asked if an UD Pulley Kit was a good mod for the money.....YES IT IS!
Congrats with modding the car, Keep it up and don't neglect the small things like The engineer said.....Before you know it 2hp adds to 20 and 20 adds to 100 and etc etc etc
James
That doesn't mean everybody will tell a difference, but I did.
Hell every car is different. I can't even believe you guys' are argueing over a UD Pulley Kit!
Best bang for the Buck is nitrous and everybody knows that. He just simply asked if an UD Pulley Kit was a good mod for the money.....YES IT IS!
Congrats with modding the car, Keep it up and don't neglect the small things like The engineer said.....Before you know it 2hp adds to 20 and 20 adds to 100 and etc etc etc
James
Launching!
Joined: Nov 2007
Posts: 271
Likes: 0
From: Moore Oklahoma
We have some “undeniable” laws of physics at-play here with the pulley issue. Basically those laws of physics state; energy is required to place mass in motion and maintain that mass in motion. Additionally, the greater the “volume” of mass, or the greater the “motion” of mass, the greater the mount of energy is required. Again, to place it in motion and maintain that motion.
Considering those basic laws of physics we look at the under-drive pulley issue. Typically, we can’t reduce or eliminate the amount of accessory rotating mass to free-up energy (with the exception of an electric water pump), that in-turn leaves us with only one option. And that is to reduce rate of motion of the accessory mass. Specifically, to under-drive the accessories (turn them at a lower RPM) requiring less energy (horse power) to drive the accessories.
Although, you guys here on the forum that go strictly by “how it feels” those laws of physics probably don’t mean too much. However, when we pair-up to race, my car will be prepared using sound engineering practices and laws of physics and your car prepared based on your emotions, or feelings.
Hey, I like that!
WD
Considering those basic laws of physics we look at the under-drive pulley issue. Typically, we can’t reduce or eliminate the amount of accessory rotating mass to free-up energy (with the exception of an electric water pump), that in-turn leaves us with only one option. And that is to reduce rate of motion of the accessory mass. Specifically, to under-drive the accessories (turn them at a lower RPM) requiring less energy (horse power) to drive the accessories.
Although, you guys here on the forum that go strictly by “how it feels” those laws of physics probably don’t mean too much. However, when we pair-up to race, my car will be prepared using sound engineering practices and laws of physics and your car prepared based on your emotions, or feelings.
Hey, I like that!
WD
Thread Starter
Banned
Joined: Oct 2007
Posts: 57
Likes: 0
We have some “undeniable” laws of physics at-play here with the pulley issue. Basically those laws of physics state; energy is required to place mass in motion and maintain that mass in motion. Additionally, the greater the “volume” of mass, or the greater the “motion” of mass, the greater the mount of energy is required. Again, to place it in motion and maintain that motion.
Considering those basic laws of physics we look at the under-drive pulley issue. Typically, we can’t reduce or eliminate the amount of accessory rotating mass to free-up energy (with the exception of an electric water pump), that in-turn leaves us with only one option. And that is to reduce rate of motion of the accessory mass. Specifically, to under-drive the accessories (turn them at a lower RPM) requiring less energy (horse power) to drive the accessories.
Although, you guys here on the forum that go strictly by “how it feels” those laws of physics probably don’t mean too much. However, when we pair-up to race, my car will be prepared using sound engineering practices and laws of physics and your car prepared based on your emotions, or feelings.
Hey, I like that!
WD
Considering those basic laws of physics we look at the under-drive pulley issue. Typically, we can’t reduce or eliminate the amount of accessory rotating mass to free-up energy (with the exception of an electric water pump), that in-turn leaves us with only one option. And that is to reduce rate of motion of the accessory mass. Specifically, to under-drive the accessories (turn them at a lower RPM) requiring less energy (horse power) to drive the accessories.
Although, you guys here on the forum that go strictly by “how it feels” those laws of physics probably don’t mean too much. However, when we pair-up to race, my car will be prepared using sound engineering practices and laws of physics and your car prepared based on your emotions, or feelings.
Hey, I like that!
WD
i totally agree and the only other mod i have is a SLP CAI and the car also seems to get much better mileage about 40 miles more on a tank. i am very pleased with my investment and mr im 19 and know everything about the whole world doesnt even understand gearing. get on a mountain bike and put it in the smallest gear and its hard to start off, now put it in the *****bigger**** gear and its much easier and takes alot of strain away. so keep talking about your bang for buck buddy. finish highschool before you come talking about it not doing anything. and my car has no charging issues at all or power steering issues either. but thanks for the supporters!
And i am going on 19 as well and that is why i try to read alot at this point to understand more but i do post about stuff that i have personally experienced doing and i think that is where the most usefull info comes from!!
So i take it you got it back from the shop and you are happy with them!?!?
And i am going on 19 as well and that is why i try to read alot at this point to understand more but i do post about stuff that i have personally experienced doing and i think that is where the most usefull info comes from!!
And i am going on 19 as well and that is why i try to read alot at this point to understand more but i do post about stuff that i have personally experienced doing and i think that is where the most usefull info comes from!!
I was thinking this was a worthless mod...but I think The Engineer has convinced me otherwise. I'll need all I can get if I ever pull up next to him!!
Great info and well put.
Launching!
Joined: Nov 2007
Posts: 271
Likes: 0
From: Moore Oklahoma
WD
Theres alot better mods for the $$ than u/d pulleys. LS1's usually gain ~10rwhp because it slows down their waterpump, our waterpumps are gear driven. I have one and I didn't notice anything when I put it on. The only reason I have one is to slow down the p/s pump on the track to help keep it cool. And if you feel like flushing $$ down the toilet for one atleast get the asp one that actaully replaces the crank pulley instead of a piggy back one.
no sense arguing speed, they are convinced that it is a good mod and dont want to listen to logic, so have fun wasting your money I have done the same this with this Lt4 kit and i was just trying to help save u guys some $$.like speed demon said at least get the one that replaces the crank pulley.
I have done the same this with this Lt4 kit and i was just trying to help save u guys some $$.like speed demon said at least get the one that replaces the crank pulley. 
Think about it this way. UDing the accessories slows the alternator, SP and AC. The AC clutch shutoff VS. TPS is programmable so it is just the clutch that should be spinning if your tune is even halfassed right. Many of you are saying with stock engines you needed to up idle or add OD alternator pullies, I will say that with a cam idle will likely be high enough to not need an OD but if you do the math at full output the electrical production demands of the alternator are just a couple HP TOTAL. That brings us too the PS, slowing this on a road race car can be benifical, on a drag car it is not doing much work going in a staight line.
As noted above pullies got popular on cars where they slow the WP which is capable of offering worthwhile gains.
The total gain in pulling the belt all together is what .1 on most cars? So let's say you actually get 34% of that so .034 seconds at the track, you can not feel that SOTP.
Once you think about the details I would hope more of you are of the opinion I have, that when I buy an aftermarket damper for better high rpm dampening I will buy an UD since they are the same price, but till then I am not going to bother.
The b-bodies are sensitive to PS overheating in road race conditions so there is a true worthwhile benifit to a UD if the car is used like that, the fewer rpms can help avoid overheating.
As noted above pullies got popular on cars where they slow the WP which is capable of offering worthwhile gains.
The total gain in pulling the belt all together is what .1 on most cars? So let's say you actually get 34% of that so .034 seconds at the track, you can not feel that SOTP.
Once you think about the details I would hope more of you are of the opinion I have, that when I buy an aftermarket damper for better high rpm dampening I will buy an UD since they are the same price, but till then I am not going to bother.
The b-bodies are sensitive to PS overheating in road race conditions so there is a true worthwhile benifit to a UD if the car is used like that, the fewer rpms can help avoid overheating.
Thread Starter
Banned
Joined: Oct 2007
Posts: 57
Likes: 0
no sense arguing speed, they are convinced that it is a good mod and dont want to listen to logic, so have fun wasting your money I have done the same this with this Lt4 kit and i was just trying to help save u guys some $$.like speed demon said at least get the one that replaces the crank pulley.
I have done the same this with this Lt4 kit and i was just trying to help save u guys some $$.like speed demon said at least get the one that replaces the crank pulley. Thread Starter
Banned
Joined: Oct 2007
Posts: 57
Likes: 0
Logic. . . And Another Logical Reason To Get The Pullies Would Be Better Gas Mileage. For A 100 Bucks I Spent On The Pullies I Get About 40 More Miles A Tank Which If You Ask Me Will Recover The Cost Of The Pullie Pretty Quickly If You Drive As Much As I Do.
So Lesson Learned : 19 Year Olds Have Better Logic Than Anyone, Including Engineers.
So Lesson Learned : 19 Year Olds Have Better Logic Than Anyone, Including Engineers.