My issue with all of this is that a lot of sources have vested interests on the topic. UAS like to sell their Ross pulleys, GFB and UR both sell their UD pulleys. Personally? Personally i've had no issue in 25 thousand k's with an UD pulley, and revving out through the mountains just the same as Chris. On 20 year old engines, it's more likely something else will give up the ghost way before the pulley causes any issues IMO
Aye but again 25k is nothing really is it, not to mention I think UAS would have sold a lot more GFB UD Pulley's than a more expensive Ross Pulley so if they wanted to sell it on profit alone they woulda stuck with the cheaper and more popular product.... Reason he changed is him himself got the problem with vibration and changing it DID fix the issue.
It's been interesting watching you make the transition from someone who knows SFA about UDP's, to someone who has a thorough grounding in Automotive Engineering and Harmonic Balancer design. Where do you get the idea that a stock VG engine does not have a harmonic balancing crankshaft pulley(like almost every other car for several decades)? :rofl::rofl::rofl::rofl:
I know that someone has already asked that we don't mention UDP's to RB engine users, but have you bothered to expound the above theory to ANYONE who has an ounce of experience in regard to harmonics?:bash:
uh oh, here we go, it's getting narki now. wasn't me, chili started it but you do have a point. it's funny how the tone changed from un-sure to one that's totally confident in the UDP after a few users agreed. then all the copy / pasted info started getting thrown around to somehow justify the decision. since it's still a trial / error thing for your car, shouldn't you remain unbiased until it's actually on? no need to try and justify it to us or anyone else, it's completetly pointless until it's done and dusted and even then i'm sure a lot of people on here probably still wouldn't accept it anyway so there is no need for all the linking. i'm open minded enough about one, if i had a rebuilt and perfectly balanced motor, sure i'd run one. on my tired 20 year old motor, even if it's completely healthy i'd still rather keep the stock balancer. re the wiki links, they are good for general information on a broad scale, it's not the bible and everytime it's quoted, it doesn't strengthen any argument but rather shows how little research has been done.
I'll steer clear of the UDP debate, I bought the Ross/UAS one for the record though With regards to engine mounts I would definitely change them if they are the originals. It's not worth having one let go once your putting out more power and having to change them after the fact once one tears. Prick of a job I would imagine. Try one of the overseas mobs like AMS or Z1 etc, or alternatively I just purchased the new Polyurethane ones from UAS. They've just gone up in price to $190 (cheaper for forum members I think) but are still far cheaper than OEM replacments. Ben
Pretty sure the UAS ones arent Polyurethane anymore cause there was problems with it breaking down to early? They dont look like it anyways http://www.nismo.com.au/pricelists/pricelist_300zxengine.htm
I'm not going to bother reading any replies to this thread - because it's all been said before on many, many threads in the past. Search will reveal all. I CAN however give a testimonial for my own personal experience using an UDP. Mine is a GFB (Go Fast Bits) brand UDP. Had it for 4-5 years now. No problems what so ever, no vibration. All my accessories work fine, even water pump (without the use of an overdrive pully for the water pump). Can't remember exactly, but my gains were between 10-15hp. Just get it, put it on and forget about it. You won't regret it.
yeah, I've had my UDP on for over 20,000K's now, all the other pulleys are standard size, no issues whatsoever, definitely a quite marked increase in throttle response, no idea of hp gains because it wasn't put on the dyno in a before and after situation, i don't perceive any noticeable vibration in any revs in any gear. I should mention that quite a bit of my driving is in extreme heat conditions as well 40C+, albeit the bulk of it out on the highway, but have also done quite a bit of city stop start with aircon full on, in a black car you melt without aircon
my turbo builder that build lumpy's front high mount turbo engine (600hp+) says he has seen a couple of high spec zed engines eat there bearings and destroy there engines due to the use of UDPS.... i had one on my old engine, never really liked the way it felt tho. and if u look at all the large Japanese builds. they ALL use the stock harmonic balancer and that's on cars running 800+ horse everyday... if u want a lighter pulley get one of the dampened ones from the US.. not 2 mention Ive seen more then a few china UDPS that have a incorrect timing mark on them...
sum 1 should post a poll thread for how many years/k's they have used an underdrive pulley. I've done over 100,000 k's over 7 years with the u/d pulley.
i dont think a UDP is going to do any real damage to a VG30, they have killed RB's but the crank is alot longer and have problems at high revs even with a stock balancer, this is not the case with the VG having said that , anyone who has balanced a VG motor will tell you they take heaps off the crank. the comments that the VG is a well balanced motor from factory are not true unfortunatley
