Ultra S Unorthodox Racing Underdrive Crank Pulley
- Thread starter Shades
- Start date
Stock pulleys are properly balanced for the vibration in the bottom end of the motor. The UDP's are not balanced. In a NA car it doesn't create enough vibration to do any severe damage. In FI cars, though, the bottom end of the motor takes a lot more abuse and has more vibration. In the FS-DE FI motors it can cause premature oil pump failure.xtrememps said:
Installshield 2
Gothenburg Superiority
This is a little misleading...UDP's are perfectly balanced...the harmonic resonance stress that affects the crank with a UDP has nothing to do with it being out of balance, and everything to do with it having less mass, or mostly less rotational inertia...xelderx said:
This problem is extremely overhyped though...Crank oscillation is always there...The amount that a stock flywheel and stock drive pulley limit oscillation stress is extremely misunderstood...They barely do...there is still significant stress on the crank with the stock pieces...increasing the output will increase this regardless of if you keep the stock pieces or switch to a lighter dampers...This is the number one reason on why most modern carmakers are using forged cranks in even their small engines recently (the FS didn't always have a forged crank)...heavy flywheels and crank pulleys were not doing a whole lot for oscillation, and cranks were failing well before the rest of the engine...the fact that a lot of engines now utilize forged cranks is the main reason some engines can hold 400whp or more reliably...its not that they kept the heavy stock pieces...its that the crank is extremely strong...
You are correct though...and I am getting off the point...the oscillation stress is far greater with a high torque FI engine compared to a NA engine (higher redlines can cause different types of oscillation though, actually in which it is better to have dampers {thats the s*** on the ends of the crank...in this case a flywheel and a drive pulley} that have less rotational inertia)...If you already have a lightweight flywheel and are planning on boosting to 250+whp, I wouldn't recommend that UDP...but if you are staying NA, or boosting less than that power output...you could have both and be perfectly fine...the forged crank is more than up for a slight increase in resonance...
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Installshield 2
Gothenburg Superiority
I guess in your defense the stock pieces are said to be "harmonically balanced"...in which case the UDP's are not balanced in that sense...just wanted to clarify that its not that the UDP's spin in an off balanced fasion the way wheels and tires can...UDP's are properly balanced for uniform rotation...
RR-Racing.com
Member
FYI, those you considering getting an underdrive pulley, I'm doing a BB on my pulley for considerably less the UR... .and I guarantee mine is higher quality.
$110 + $10 shipping.... check out the bulk buy forum.
Rafi
$110 + $10 shipping.... check out the bulk buy forum.
Rafi
OK. Ordered the UR Pulley and waiting anxiously for it. How much are the Gates belts usually? I noticed a lot of ppl are saying that they feel a noticebly better response. How noticable is it exactly? My PR5 is pretty much stock except with an INJEN intake and TSUEDO exhaust.
RR-Racing.com
Member
just curious...
Hi, I am just curious mainly because I want to know perhaps there is something that I can do better in order to earn your business. Why would you buy an Unorthodox racing brand pulley and pay 30% more for it when you can can buy my RR-racing pulley (which is better by the way) and save yourself a lot of money...
thanks,
Rafi
Hobbit998 said:
Hi, I am just curious mainly because I want to know perhaps there is something that I can do better in order to earn your business. Why would you buy an Unorthodox racing brand pulley and pay 30% more for it when you can can buy my RR-racing pulley (which is better by the way) and save yourself a lot of money...
thanks,
Rafi
Hobbit998 said:
Gates belts are recommended for the UR pulley because UR pulley is smaller than stock pulley, and stock belts wont fit (you will have big ass slack with stock belts) thats why you need Gates belts. Not because they will give you a better response.
Punch in your zip code: http://www.gates.com/automotive/distributors/index.cfm?location_id=539
Pep Boys and Autozone suck ass anyway.
Pep Boys and Autozone suck ass anyway.
First it doesnt realy matter if you us gates or not it is just the size. Ko40355 just means 4 groove belt that is 35 in a half inches long. Ko50446 just means a 5 groove belt that is 44 . 6 inches long. Go to any auto shop and just ask for a 355 k4 belt or 446 k5 belt since most manufactures use those part numbers. Also 360 k4 and 459 k5 are just stock sizes their isnt that much difference in belt size differences. I actually used a 355 k4 for the alternator and same stock belt for power steering just tightened it more. I have the rr racing underdrive pulley that is just the same thing. Oh yeah I forgot I work for autozone.
