Dodge SRT Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
1,019 Posts
Discussion Starter · #3 ·
They are possibly using a damper for a different vehicle with a hub that fits ours.

Still, since the underdrive pulleys without a damper are possibly causing oil pump failures, this should be a really good peice.
 

·
Registered
Joined
·
1,630 Posts
Not many people use them, a couple 2.0 neon guys but seems like a good Idea. Now there are some 500+ hp cars out there w/ udp's and no probs, most of it is in the tune.
 

·
Registered
Joined
·
378 Posts
Pulleys like these are actually required for several types of drag racing, and a majority of the higher revving, high power guys are using them.

You probably wouldn't need something like this on these motors unless you are either making over 700 hp or revving to about 8000 RPM. Not to mention the fact that they cost about $500+.
 

·
Registered
Joined
·
19 Posts
05plsrt4 said:
since the underdrive pulleys without a damper are possibly causing oil pump failures
Improper tuning with big HP increases cause oil pump failures also using the wrong thickness of oil, boost spiking, cold revving and increased rev-limts will cause the same failure. A powdered metal oil pump cannot handle large increases in power and even the slightest detonation at 50+ HP more than stock can cause these gears to shatter. The only answer for big power increases is an external dry or wet sump oiling system. Guys are willing to spend 1000's for power but not spend about 1000 once to solve this problem. One engine rebuild is much more than porper oiling. Solid aftermarket crank pulleys have nothing to do with the failure, the oil pumps fail with a stock pulley, that goes for the SRT4, Honda engines or any engine with gerotor type pump. Aftermarket dampers will not help either, especially since they are not tuned to the smaller engines properly, not to mention they are heavier than the stock pulley and cause losses in power from beign heavier. Last but not least they cost twice as much as a stock or quality underdrive pulley.

Stop the urband legend/myth.

Shawn
 

·
Banned
Joined
·
32,448 Posts
Damn, URI I hope to hell you have proof of what you are saying.

The odds are against you. Several have installed LW UDP's and had the gears crack on them and these are not 300 WHP SRT4's. I will share with you what I have found out from my supplier. We spent $1800 on our UDP to have the harmonics tested and to our surprise the lighter we went the more problems we came up with. So we decieded to go big and add some heavy elasometer to the pully. So far so good. There is a bad spot in our motors at 4200 and 6700 RPM. This is what we designed our pully for, not to be light weight or for a reduction is size but for those few that want to keep the stock pump gears and protect them from the crank harmonics. Now what you are saying about running a dry sump system makes sence but the room under the car or even better finding the mounting solution is far to tough for most shops. There is very little room to work with and the next best solution is to fix the end of the crank. Does this make me any better, nope just makes me more informative on the workings of the SRT4 motor.
 

·
Registered
Joined
·
1,630 Posts
ptperformance said:
There is a bad spot in our motors at 4200 and 6700 RPM.
This is also around the peak torque area where detonation is most prevalent.

How do you explain cars w/ UPD's and stock oil pump gears that put down over 500whp w/o oil pump probs?
 

·
Banned
Joined
·
32,448 Posts
SpeedEuphoria said:
ptperformance said:
There is a bad spot in our motors at 4200 and 6700 RPM.
This is also around the peak torque area where detonation is most prevalent.

How do you explain cars w/ UPD's and stock oil pump gears that put down over 500whp w/o oil pump probs?
The move through the bad spots quick enought or are not held there like some dynos do for tuning. To be totally honest I have not idea. I didn't have a 500 WHP SRT4 when we did our testing for the pully. It was a stock one. The company that did the testing for us (BHJ) has done this for many other vehicles in the past and have a very good rep for getting it "right".

Now from what I can tell is bigger turbo cars have lots of lag and they don't put down the TQ number like stage 3 or stock turbo down low. What we did experience during our testing is the vibes became much worse when the WTQ went up vs the WHP. The quicker we brought the boost on the more vibes we got with the testing equipment.

I could turn around and say look at how many UDP and stock turbos have blown up oil pump gears but I don't have any idea as to how "many" that would be. I do know that there are more big turbo cars with damaged pump gears than stock turbo. I guess you can take that for what its worth.
 

·
Registered
Joined
·
1,075 Posts
05plsrt4 said:
They are possibly using a damper for a different vehicle with a hub that fits ours.
yes it has a seperate hub. a few of the 2.0/2.4 swapped 1gs are running the ATI, the only gripe they have is they dont have a alternator only pulley.
 
1 - 11 of 11 Posts
Top