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DJ Ambiguous
Registered Whiner
Posts: 4640
(1/25/04 3:12 pm)
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underdrive pulleys?
opinions? unorthadox racing sells the crank pulley for $183 US on ebay... with the removal of the waterpump fan and powersteering this should give the Naturally aspired bluetop a bit more juice?
DJ Ambiguous
1985 AE86 - GTS Hatch (It's not easy being green!)
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wingnut7
Registered User
Posts: 19
(1/25/04 7:22 pm)
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Overdrive pulleys!
hmm....i think it should add a bit more power because the engine would not have to drive the 2 other accesory belts. but you'd have to get your hands on a electric fan from something i think one from a supra is suppose to work or was it a camry? ask mac he might remember. plus you'd have to loop yor power steering lines, shouldn't be that hard.
"Speed is an addiction that can only be cured by poverty"-Team Cipher
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DJ Ambiguous
Registered Whiner
Posts: 4641
(1/25/04 8:26 pm)
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Re: Overdrive pulleys!
yeah jimbo, i got a camry fan.. i am gonna being doing all this as soon as it warms up.. chucking the Power steering, ditching the waterpump fan.. hopefully u bro's can help me...
DJ Ambiguous
1985 AE86 - GTS Hatch (It's not easy being green!)
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majicmeow
weeeeeeeeeeeeee!
Posts: 800
(1/25/04 11:02 pm)
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Re: Overdrive pulleys!
underdrive pullies = death!
Dont do it man... not worth the risk!
check this out... Dinan is a VERY respectable name and if they dont use them, I wouldnt...
Danger of Power Pulleys
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"Technology is the only substitute for cubic inches"™
1982 MA67 Poopra... uh, Supra =)
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1985Trueno 
will race for food
Posts: 3816
(1/26/04 4:21 am)
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Re: Overdrive pulleys!
that's why Japanese aftermarket part manufacturers only make larger water pump pulleys and P/S pulley but not smaller crank pulley.
Opinions are like assholes, we all have one.
-David Coulthard Edited by: 1985Trueno at: 1/26/04 4:22 am
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st204 
Registered User
Posts: 292
(1/26/04 9:55 am)
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Re: Overdrive pulleys!
There seems to be a mixed batch of people for and against it. Dinan is a VERY respectable company so I would think that they know what they are saying. But what about 4AGZE crank pullies that HKS makes for more boost? People have been using them happily for almost 20 years. Not to mention, Bill Sherwood uses lightweight underdrive crank pullies on his race engines. I would like one too, not to underdrive but just for the weight savings off the front end. But I'd only do it if I was sure it was safe. So far, I'm not convinced, but close. Anyone else have opinions?
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1985Trueno 
will race for food
Posts: 3817
(1/26/04 10:15 am)
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Re: Overdrive pulleys!
If it's race engine the longevity is not that much of a concern don't you think? It has to last at most like 24 hours? Think about it. Some aftermarket underdrive pulleys do have harmonic dampeners (The one my friend bought for the C230 Coupe kompressor, for one) so those would be fine I guess...?
Opinions are like assholes, we all have one.
-David Coulthard |
SupraFiend
registered supra fanatic
Posts: 4199
(1/26/04 12:09 pm)
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Re: Overdrive pulleys!
Iit basicly just depends on the motor and what the pulleys do exactly. Lighter accesory pullies won't hurt anything. But underdrive ones can produce undesirable results. Do you really want your alternator and water pump running slower then they do already? For the water pump thats just a bad idea, and most old toyotas seem to have rather weak alternators so slowing them down even more isn't the greatest idea. As for the crank pulley, if your motor uses a harmonic balancer don't even think about it. And I think most toyotas do. I know some motors like mustang 5 liters have the harmonic balancer incorporated into the flywheel so it wouldn't hurt on a motor like that but if not forget about it. Basicly with our motors if you can get lighter but same size accesory pulleys go for it but forget about everything else.
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Pentavalver
Registered User
Posts: 868
(1/26/04 4:26 pm)
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.
st204,last I heard,the person you mentioned used certain
program to redesign the factory waterpump pulley.Pretty much cooked the engine.
Still to this date,that same person,has never built anything closely related to a "race engine".
Keep in mind that a lot of negative feedback never hits the papers because ego prevents the truth being disclosed.
Underdrive pullies are a wank.
As I have said before,just because a product hits the market does not mean it will do anything for any1 besides line the sellers pockets with dead presidents.
Supercarger pulleys are a different concept.My opinion on them is that without management,they deplete power by overheating the inlet charge,inturn,depleting the power output.
Majic,thanks for the link,backed up my theories nicely.
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majicmeow
weeeeeeeeeeeeee!
Posts: 800
(1/26/04 5:52 pm)
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Re: .
no problem =) Ive had that link around for a LOOONNNGG time.
My uncle Reg sent me this link after he saw an M5 blow up on his dyno because of the pullies. Since the pictures of the mess and his explaination, Ive spread the word to as many people as I can!
Since then he has also written an article about this... Ill try to find that link as well =)
Cheers
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"Technology is the only substitute for cubic inches"™
1982 MA67 Poopra... uh, Supra =)
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cjopant
Registered User
Posts: 445
(1/26/04 6:28 pm)
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Re: .
Ok, I have a question about fatigue failure. The article describes it as being caused by "The vibration of the engine and its rigid components caused by the imbalance of the rotating and reciprocating parts." it goes on to state "This is why we have counterweights on the crankshaft to offset the mass of the piston and rod as well as the reason for balancing the components in the engine."
Now, what would happen if I got Toda pistons or something like that. Wouldn't the weight change make the counterweights on the crank be too heavy? That would cause fatigue failure as well, wouldn't it?
I don't really have any experience with this, do I have the right idea, or am I completely clueless here?
Edited by: cjopant at: 1/26/04 6:34 pm
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narf13 
Registered User
Posts: 144
(1/26/04 8:31 pm)
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electric fans
i have an electric fan coversion in my AE86... as soon as the crank fan was removed, i felt much quicker throttle response, and now that the electric fan is up and running properly, it's not gonna over heat when i RIP up SFU and then into a parking lot...
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aw101x
god of the spetunk
Posts: 4738
(1/26/04 11:05 pm)
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Re: electric fans
alright, call me a doubter...
i am not saying that an aluminum crank pulley can't have a somewhat detrementral effect on your engine, fuck, i got no idea, BUT, if this was the case, why haven't i heard of all kinds of people having catastrophic engine failures?
think about it, so many honda (and other manufacturers) guys run them, i never hear of complaints...come to think of it, i have never after years of posting and talking with other guys heard of anyone blowing thier engines because of their crank pulley.
i dunno, i got no proof either way, but you'd think that this would have come up alot more often if a crank pulley meant death.
there are several guys on the mr2 board running them, not just s/c guys, but n/a guys, never heard of wrecked bottom ends form them...
call me a skeptic....well...maybe i jsut thinkk that this is one side of the story, and that this isn't all the information one should be exposed to before making a decision.
how many different articles have we all seen on engine oil engine oil filters, i ahve seen toyota filters at every end of these charts, top and bottom, in the middle, spark plugs..there are lot's of companies providing proof that 4 tipped iridium shit whatever plugs make more power, ignition systems, hell, even the teflon oil filters that coat your enigne with teflon were sold by some people as god sends, then attacked by others as crap.
why isn't everyone with a lightened flywheel blowing engines then? that should change the harmonics of the bottom end yes? lighter rods, shit like that, do the FA engines use the harmoic balancer? i know there is a hell of alot of lightened comonents in them....what do they die of?
ass poo ass poo ass poo ass poo Edited by: aw101x at: 1/26/04 11:06 pm
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Pentavalver
Registered User
Posts: 868
(1/27/04 5:51 am)
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.
Straight fours are probably the least susceptable to these sorts of vibrations,but inline 6's and V's...
I just cant justify the expense,also,alu fatigues much faster than steel.
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aw101x
god of the spetunk
Posts: 4741
(1/27/04 7:47 am)
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Re: .
i suppose something with a forged crank and strong block would further resist damage too...
neat.
ass poo ass poo ass poo ass poo |
SupraFiend
registered supra fanatic
Posts: 4203
(1/27/04 10:45 am)
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Re: .
My buddy duane with his 480rwhp mk3 supra was using underdrive pulleys with a replacement for the crank pulley. He was expericencing sever crank walk and bad vibrations and almost killed his freshly built motor. He switched back to the stock crank pulley and all is good.
It has alot to do with time and power too. In Duanes case he was making tons of power and the imbalance was immediatly noticalble. Most of these ricers running these things are only making like 100whp. So if the vibrations aren't immediatly noticable then its going to be more of a long term thing, their motors wear out prematurely. And when that happens how do you chalk that up to just one thing? You don't. And like I said before, not all manufactures balance their motors the same. Not every car's main crank pulley is necesarily a harmonic balancer. But they are definatly on all 4ages and all M engines, probably most toyota motors I imagine.
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Pentavalver
Registered User
Posts: 868
(1/27/04 4:38 pm)
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.
That reminds me.When I get my cranks balanced,the machiners want pulley,crank and flywheel.There bolted together as 1 unit and dynamic balanced.There marked as to which point they are to be final assembled.This is how critical balance is,so to buy a solid pulley and bolt it on coz its a pretty anodised gold seems to defeat the purpose.
Cj,pistons as long as there balanced between each other have little effect on engine dynamics.Going lighter is allways the optimum though.
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