qwarrior Posted February 15, 2012 Share Posted February 15, 2012 I have replaced the standard crank pulley once already in the time I've owned my Supra. It appears to have failed again, I'm looking into replacements and am torn between spending a bit on cash on an ATI damped pulley from Paul at Whifbitz and the Japspeed solid lightweight pulley for significantly less cash. Link below. http://www.japspeed.co.uk/Toyota-Supra/Engine-Tuning/Toyota-Supra-Mk4-Lightweight-Crank-Pulley/p-28-73-498/ Can any of you chaps enlighten me on the benefits of having a damped pulley at all against saving my cash for other bits and going for the lightweight machined pulley? Quote Link to comment Share on other sites More sharing options...
stevie_b Posted February 15, 2012 Share Posted February 15, 2012 What mods have you got? I would get a stock one unless you know of a good reason not to do so. Chris Wilson posted some good info recently on another thread to do with pulley dampening and the reasons for it. Quote Link to comment Share on other sites More sharing options...
qwarrior Posted February 15, 2012 Author Share Posted February 15, 2012 What mods have you got? I would get a stock one unless you know of a good reason not to do so. Chris Wilson posted some good info recently on another thread to do with pulley dampening and the reasons for it. Just BPU decat really, few other little bits n bobs, but I keep breaking them. To give example prices: ATI Damped about 400-450 quid, Stock damped 200-220 quid, Solid machined 55 quid. I'll search fro Chris's posts, but I'll need at least 350 quid's worth of good reason not to spend 55 quid. Quote Link to comment Share on other sites More sharing options...
James Posted February 15, 2012 Share Posted February 15, 2012 You have really answered your own question, without realising it The crank at the front gets the impulses from just the no 1 cylinder, and as you move back along it the crank gets the torque pulses from more and more cylinders, until the last main bearing section is seeing all six firing pulses. So you have differential torque loadings along its length. Add to that the pulses are sometimes unequal, but a straight six is pretty much OK in that regard, which is why they are normally such sweet running engine formats. Then, and this is the bit you answered yourself, you have differential inertia. The front of the crank just "spins" and maybe drives some ancillaries. the back end has a dirty big flywheel to give inertia to the engine for added smoothness and easy starts, both as in firing the engine up from stopped, and driving smoothly away from a standstill on the road. Add the pulses, the unequal torque loading along its length, and the unequal inertia, front and rear and the crank is constantly twisting and untwisting (literally, but fractionally) all the time the engine is running. At certain RPM's and loadings it will twist a LOT relatively speaking. These are the crank harmonics, a BAD thing. The front damper's job is to calm these motions to stop the thing fatiguing and eventually failing catastrophically. Now, that's a pretty simplistic explanation, but basically the damper tries to damp down twisting movements, the same as the dampers on the road springs dampen the car body's oscillations up and down. If you have knackered, or no dampers (shock absorbers as they are so often wrongly called), the car's body vertical motion is violent, uncontrolled and potentially dangerous and unstable. By removing, or sometimes just altering the crank damper, you are basically doing the same to the engine, albeit the results are not usually immediately obvious. HTH. Surely the rest of your engine is £350 worth of reasons to go OEM Quote Link to comment Share on other sites More sharing options...
stevie_b Posted February 15, 2012 Share Posted February 15, 2012 They are damped for a reason: there are massive twisting forces going through the crankshaft. If the parts and labour to rebuild your bottom end is more than £350, there's your reason. I'm not sure why you're considering the ATI one, at about double the cost of a stock one. Don't assume that because it's from a tuning house, it must be better. I can't imagine that ATI have spent more R&D money than Toyota on testing it specifically on a 2JZ engine. Quote Link to comment Share on other sites More sharing options...
qwarrior Posted February 15, 2012 Author Share Posted February 15, 2012 They are damped for a reason: there are massive twisting forces going through the crankshaft. If the parts and labour to rebuild your bottom end is more than £350, there's your reason. I'm not sure why you're considering the ATI one, at about double the cost of a stock one. Don't assume that because it's from a tuning house, it must be better. I can't imagine that ATI have spent more R&D money than Toyota on testing it specifically on a 2JZ engine. Reasonable point. (TBH I wasn't really considering an ATI one just looking at the options) I just don't want to have to replace another one in 6-12 months time. Quote Link to comment Share on other sites More sharing options...
David P Posted February 15, 2012 Share Posted February 15, 2012 If your OE pulley died in that time, take it back to Mr. T. Quote Link to comment Share on other sites More sharing options...
Jellybean Posted February 16, 2012 Share Posted February 16, 2012 What is the Power limitation for a stock Crank Pulley and from what I read it is recommended you use an ATI Pulley if you run over X power; why do they recommend using an ATI pulley, surely crank harmonics are more pronounced with a higher powered engine? Should you ever consider an ATI pulley? Quote Link to comment Share on other sites More sharing options...
dive_popo Posted February 16, 2012 Share Posted February 16, 2012 What is the Power limitation for a stock Crank Pulley and from what I read it is recommended you use an ATI Pulley if you run over X power; why do they recommend using an ATI pulley, surely crank harmonics are more pronounced with a higher powered engine? Should you ever consider an ATI pulley? Interested in the answer aswell... Quote Link to comment Share on other sites More sharing options...
Dnk Posted February 16, 2012 Share Posted February 16, 2012 If your OE pulley died in that time, take it back to Mr. T. Pretty sure you only get 12 months on o/e parts from Toyota Also a genuine not copy o/e crank pulley is £290.11 + vat less whatever discount you can get out your local dealer. Quote Link to comment Share on other sites More sharing options...
Lude Posted February 17, 2012 Share Posted February 17, 2012 i just got a new one £220 from whifbitz, toyota were £290. i woudnt get a cheap copy as apparently they are quite important Quote Link to comment Share on other sites More sharing options...
Dnk Posted February 17, 2012 Share Posted February 17, 2012 i just got a new one £220 from whifbitz, toyota were £290. i woudnt get a cheap copy as apparently they are quite important Isn't the Whifbitz one a copy according to the info on the website ? but apparently made to the same standard ? I guess it could be just as good but how would you know ? the sales blurb also says its half the price of the Toyota one which it obviously isn't ! Quote Link to comment Share on other sites More sharing options...
stevie_b Posted February 17, 2012 Share Posted February 17, 2012 Like Lude, I bought one from Whifbitz which was Toyota OEM but cheaper than what the dealers were selling them at. Quote Link to comment Share on other sites More sharing options...
Lude Posted February 17, 2012 Share Posted February 17, 2012 its not half the price no. but its cheaper. i trust whifbitz so i went for it Quote Link to comment Share on other sites More sharing options...
Scott Posted February 17, 2012 Share Posted February 17, 2012 Like Lude, I bought one from Whifbitz which was Toyota OEM but cheaper than what the dealers were selling them at. As in not this one? http://whifbitzperformancetuning.co.uk/toyota-supra-supra-engine-components-camshafts-pulleys-belts-garage-whifbitz-p-5968.html I think I remember Paul selling the stock dampener but it was more expensive than my local MrT. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted February 17, 2012 Share Posted February 17, 2012 It wasn't that one Scott. It was definitely sold as a genuine Toyota OEM one. It also came in a Toyota box (although that doesn't prove anything). With something like the crank pulley and because my car is 95% stock (completely stock engine-wise), I wouldn't fit anything other than OEM, but that's just me. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted February 17, 2012 Share Posted February 17, 2012 That's the fella --> http://whifbitzperformancetuning.co.uk/toyota-supra-supra-engine-components-toyota-parts-toyota-p-1802.html (I would have edited the last post, but something's happened to my Firefox profile which means I can't edit any posts ) Quote Link to comment Share on other sites More sharing options...
Lude Posted February 17, 2012 Share Posted February 17, 2012 As in not this one? http://whifbitzperformancetuning.co.uk/toyota-supra-supra-engine-components-camshafts-pulleys-belts-garage-whifbitz-p-5968.html I think I remember Paul selling the stock dampener but it was more expensive than my local MrT. thats the one i just purchased. whifbitz one (copy) is cheaper than the toyota one. toyota wanted £290. unless you mean paul selling the actual OEM part cheaper than toyota Quote Link to comment Share on other sites More sharing options...
Scott Posted February 17, 2012 Share Posted February 17, 2012 That's the fella --> http://whifbitzperformancetuning.co.uk/toyota-supra-supra-engine-components-toyota-parts-toyota-p-1802.html (I would have edited the last post, but something's happened to my Firefox profile which means I can't edit any posts ) Yup that's the chappie. It's came down in price since I last looked, that's the same price as I got from my local MrT (£280). For the sake of the difference in cost I would always go with OEM over a copy, regardless of how good it is, when talking about those areas of the engine. The only reason I went with the ATi is that it's been proven not to fail under extreme situations. If I was mostly stock it wouldn't even be a second thought while ordering an OEM one. thats the one i just purchased. whifbitz one (copy) is cheaper than the toyota one. toyota wanted £290. unless you mean paul selling the actual OEM part cheaper than toyota Yeah I was pretty sure Paul did the genuine ones too, as per the above link he still does Quote Link to comment Share on other sites More sharing options...
Hellstrom Posted February 17, 2012 Share Posted February 17, 2012 Yup that's the chappie. It's came down in price since I last looked, that's the same price as I got from my local MrT (£280). For the sake of the difference in cost I would always go with OEM over a copy, regardless of how good it is, when talking about those areas of the engine. The only reason I went with the ATi is that it's been proven not to fail under extreme situations. If I was mostly stock it wouldn't even be a second thought while ordering an OEM one. Yeah I was pretty sure Paul did the genuine ones too, as per the above link he still does ATI ones overdrive pas/alternator/A/C tho. Fluidampr is à better choice in that aspect --- I am here: http://maps.google.com/maps?ll=57.729225,11.786115 Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 18, 2012 Share Posted February 18, 2012 I have replaced the standard crank pulley once already in the time I've owned my Supra. It appears to have failed again, I'm looking into replacements and am torn between spending a bit on cash on an ATI damped pulley from Paul at Whifbitz and the Japspeed solid lightweight pulley for significantly less cash. Link below. http://www.japspeed.co.uk/Toyota-Supra/Engine-Tuning/Toyota-Supra-Mk4-Lightweight-Crank-Pulley/p-28-73-498/ Can any of you chaps enlighten me on the benefits of having a damped pulley at all against saving my cash for other bits and going for the lightweight machined pulley? In what way has it failed again? Has the engine got any modifications? Quote Link to comment Share on other sites More sharing options...
Scott Posted February 18, 2012 Share Posted February 18, 2012 ATI ones overdrive pas/alternator/A/C tho. Fluidampr is à better choice in that aspect --- I am here: http://maps.google.com/maps?ll=57.729225,11.786115 I think Fluidampr is a better choice in most respects to be honest, if I had known about it before purchasing the ATI then that's the way I would have went Quote Link to comment Share on other sites More sharing options...
fuldhat Posted February 18, 2012 Share Posted February 18, 2012 ATI will never fail, that is why it is more expensive. About the overdrive, then it is minimal Quote Link to comment Share on other sites More sharing options...
Hellstrom Posted February 18, 2012 Share Posted February 18, 2012 ATI will never fail, that is why it is more expensive. About the overdrive, then it is minimal Not really as in most cases when someone change they have upgraded the engine and in most cases they rev the engine more, the bigger diameter Will overdrive it even more. Also its more likely to make the belt jump off from what ive heard. --- I am here: http://maps.google.com/maps?ll=57.709385,11.773067 Quote Link to comment Share on other sites More sharing options...
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