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Old 04-24-2008, 09:46 PM   #1
jobxiii
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Default Lightweight crank pulley + Lightweight Flywheel. OK or Not ?

anybody running these mods with any problems? i have read countless write-ups on the lightweight crank pully but how many of us are running it with a 9.5 flywheel and is it a good idea?
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Old 04-24-2008, 11:16 PM   #2
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Ive been having trouble with stalling when I come to a stop with a lightweight flywheel + lightweight pulley.

Dont know if thats the cause tho.
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Old 04-25-2008, 04:59 AM   #3
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well you could get cel.
13 lbs flywheel will not get you a cel.
but both lightened flywheel & pulley will get a cel.

so after about 20~30 pulley / flywheel combos.
what we found was flywheels lighter than 13 lbs highly
increase your chances of getting a cel for misfire
due the lighter weight of rotating mass.

also 13 lbs with lighten pulley increased the chances for
misfire cel from crank sensor.

yes there are some cars that might not give these codes.
but the majority of the cars have thrown the code
for misfire..

you also reflash your ecu rom file and turn off the cel
for crank sensor misfire. but there is always a good
and bad side to things.

pretty sure this was already discussed and if you searched
you could have gotten the answers you're looking for.
and the combinations that work & don't work.

Last edited by jaxscuby; 04-26-2008 at 10:19 AM. Reason: moaning & groaning
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Old 04-25-2008, 07:43 AM   #4
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The day I can read braille with my ass I'll go for a lightened crank pulley.
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Old 04-25-2008, 12:13 PM   #5
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I have both and never had a CEL.

Perrin Pulley with a 13 lb ACT flywheel. It's on an STI plate in my wrx 5 speed box.

I redline it to 7200+ and have never had any CEL from it.

I vote we change the canned response to this question, which has been asked before, from "You WILL get a CEL." to "You very well MIGHT get a CEL, but at least one person in the world has run both, and never had a CEL. His name is Brox, and either he is a sorcerer, a liar, or very lucky."

/Brox
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Old 04-25-2008, 12:35 PM   #6
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not a problem on our 06 sti

we used act streetlite flywheel (13lbs)
gimmick motorsports lightweight crank pulley
and acpt carbon fiber driveshaft...which is much less then just flywheel and pulley

no issues
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Old 04-25-2008, 12:44 PM   #7
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-what is this car used for, if DD i wouldnt suggest the combo, the lightened flywheel really drops the rotating mass and you have to really get it moving again aka slip the clutch a bit.

if you want to be more competitve at the track then the freaking thing rocks, blipping the throttle for shifts is great and coming out of turns and shifting up is awesome.

if you are in traffic alot prepare to suffah!
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Old 04-25-2008, 12:48 PM   #8
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why would you suffer in traffic? if you use the 9.5 flywheel which chatters..yes it would get annoying. but using any higher end clutch would be annoying in traffic. although even an exedy 3 puck stage 2 was fine with this combo in traffic...and it has next to no give. really all its going to do is let you rev faster/go through the gears faster. i can see your point in stop and go traffic for the quicker revs and using the clutch a little more, but if you have a beefy one, its not an issue. also cutting 1.6 60ft's on the stock clutch, she lasted a long time, in fact she never wore out, we just replaced her when we did the larger turbo setup.
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Old 04-25-2008, 01:05 PM   #9
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I ran a act pro lite (9 pound) and perrin pulley with my hybrid. Had to idle it at 1100 and pull a little bit of idle timing to 100% prevent stalling, but with how snappy it is around town, and how quick the revs go up and down, I liked it a lot better than the stock flywheel with perrin pulley like I run now. Ran the 2002 WRX rom and never ever a CEL. If your car doesnt misfire, it wont get a cel. And you can reflash to an updated ROM if you have the old 02 rom that throws phantom misfire codes even stock... the whole "it will throw a CEL" stereotype is from the early 02 WRX's.. and no other cars apply to that thinking....
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Old 04-25-2008, 02:22 PM   #10
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jobxiii's car is his daily driver. I helped him put it together. Specifically, he's using the Fidanza 9.5lb flywheel and a Cobb (i think) lightweight pulley. He also has a ClutchMasters clutch (FX200 if I remember right)

I don't think his CEL is on, but I will check with him today at work.

His real question is, is it safe to use both on a DD car?

There have been numerous threads here and elsewhere that claim that this combo will cause problems like timing belt jumping and bearings going out.
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Old 04-25-2008, 03:43 PM   #11
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perfectly safe! it required more work to get the car moving, and being in socal traffic FTL.

imho Great for track not street.
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Old 04-25-2008, 11:22 PM   #12
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I DD'd my wagon every day with the pulley and flywheel. I did notice it was harder but not difficult, to get moving, especially in reverse. I originally chalked it up to the STI clutch which also went in at the same time.

As for a real benefit, the thing I noticed was using launch control. 2 WRX 2.0's set up at the same LC point, mine would bounce faster than the one with no weight off the crank. It was small but noticeable so the rev faster concept I would agree with. It also comes off rpm faster as well which is why I am switching back to the stock pulley when the dogbox goes in.

/Brox
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Old 04-26-2008, 12:31 AM   #13
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I think a lightweight pulley is detrimental to the front of the suby motor. It doesn't have any hormonics control throughout the rpm range. This also causes hormonics in the oil pump and may cause oil pressure problems at high rpms.
wittmer 25 runs a light flywheel in a 04 sti and it creates cels at low rpm when you decelerate. He is also using a ATI front balancer because he wants his motor to last for awhile.
I have a brand new perrin I installed and removed before I decided on the ATI balancer I will sell if someone wants it. I also have another brand that also came with a altenator pulley that I will sell.

Last edited by charliew; 05-02-2008 at 06:13 PM.
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Old 04-26-2008, 02:38 AM   #14
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After a bit of debate, we decided that the stock pulley is going back on.
Considering the weight reduction in the flywheel, I don't think there will much of a noticable difference in driving between the pulleys.
We think the few added pounds are worth the assurance. Better safe than sorry.

Only one slight problem...
After cleaning the garage after the project, the stock pulley managed to end up in the trash.
Soooo...
If you happen to have a stock crank pulley for an 04 STI for cheap, please PM jobxiii.

Thanks to all of you for your input on the matter.
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Old 04-26-2008, 08:44 AM   #15
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IMO, the only pully i'd put on that was "light weight" is the ARFab crank pulley.

BTW, i love my exedy twin plate.
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Old 04-26-2008, 09:00 AM   #16
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Quote:
Originally Posted by charliew View Post
I think a lightweight pulley is detrimental to the front of the suby motor. It doesn't have any hormonics control throughout the rpm range. This also causes hormonics in the oil pump and may cause oil pressure problems at high rpms.
wittmer 25 runs a light flywheel in a 04 sti and it creates cels at low rpm when you decelerate. He is also using a ATI front balancer because he wants his motor to last for awhile.
I have a brand new perrin I installed and removed before I decided on the ATI pulley I will sell if someone wants it. I also have another brand that also came with a altenator pulley that I will sell.
this is a SUBARU engine.. which by nature is VERY balanced.. Not an 8,000rpm Honda engine. Not going to hurt anything what so ever
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Old 04-26-2008, 09:16 AM   #17
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Quote:
Originally Posted by sidewayz View Post
this is a SUBARU engine.. which by nature is VERY balanced.. Not an 8,000rpm Honda engine. Not going to hurt anything what so ever
that sure as hell is a matter of opinion, isn't it?
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Old 04-26-2008, 10:43 AM   #18
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Quote:
Originally Posted by sidewayz View Post
this is a SUBARU engine.. which by nature is VERY balanced.. Not an 8,000rpm Honda engine. Not going to hurt anything what so ever
well, just to let you know they are only balanced to a certain spec

have you ever spun or balanced a factory crank and seen how far off it is? just because by design it is "balance" doesn't mean it is real world balaced.

I will never run a lightened pulley/flywheel. the only way I would is if both were independantly balanced and the rotating assembly was balanced either perfectly or to spec WAAAYYY beyond what the motor would be seeing. so like I said, I would never run them combined.

Harmonics and unbalanced components are one worry I will keep 2 lbs in rotating mass to keep my engine safe. Its insurance, especially when you are going to spin high rpms.
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Old 04-26-2008, 11:10 AM   #19
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^^ agreed, but you gotta admit the RPMS needed to actually really do any harm is up high for an extended amount of time. Im talking around 8kish

Of course I've been wrong before But I don't think I've ever seen anyone say that a lightened pulley was the cause to an engine failure.
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Old 04-27-2008, 05:33 PM   #20
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Subys buy design are balanced good enough for your wife to go to the store in the snow. They are not as easy to balance as a honda. There is not enough room to add the needed weight easily. Bad harmonics is hard to pin down but the engineers in the racing world use very well designed balancers. Don't talk about light weight pulleys until you have studied the harmonics produced in a motor. Do you actually think the manufacturer's would put one on if they didn't think it is needed. And don't you think nascar would be using them if they were better?

Check out what brand balancer nascar uses.

The high performance suby needs all the high tech balancing you can buy.
This has been discussed very throughly here before. The stock balancer is like any other, it is designed for a very limited rpm range. It's good for regular driving. Also the 2.0 stock pulley is different from the 2.5 pulley. why would they redesign the pulley if it's not necessary?

Oh yeah the 04 sti pulley appears to be the same part that goes on the other 2.5 motors. It is a three piece balancer. The 2.0 is a two piece.

Last edited by charliew; 04-27-2008 at 05:46 PM.
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Old 04-27-2008, 09:10 PM   #21
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Quote:
Originally Posted by charliew View Post
Subys buy design are balanced good enough for your wife to go to the store in the snow. They are not as easy to balance as a honda. There is not enough room to add the needed weight easily. Bad harmonics is hard to pin down but the engineers in the racing world use very well designed balancers. Don't talk about light weight pulleys until you have studied the harmonics produced in a motor. Do you actually think the manufacturer's would put one on if they didn't think it is needed. And don't you think nascar would be using them if they were better?

Check out what brand balancer nascar uses.

The high performance suby needs all the high tech balancing you can buy.
This has been discussed very throughly here before. The stock balancer is like any other, it is designed for a very limited rpm range. It's good for regular driving. Also the 2.0 stock pulley is different from the 2.5 pulley. why would they redesign the pulley if it's not necessary?

Oh yeah the 04 sti pulley appears to be the same part that goes on the other 2.5 motors. It is a three piece balancer. The 2.0 is a two piece.
WOW now that i think about it the 2.5L's do use a diferent style pulley i never thought about looking at that when puting a 2.5 short block in my 02wrx. i just threw on the 2.0 pulley. do u know if that could be a problem? cause i completely agree with the balancer being vital to longevity of the bottem end in any motor. but then again i have put about 40k now on setup and i drive like i stole it everyday so maybe ill be alright. Oh one other thing u think the phase1 2.5L DOHC motor's pulley is the same? just cause i know i got one in my box at work.
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Old 04-27-2008, 09:23 PM   #22
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I havent had any problems with stalling since I switched back to the stock crank pulley., and honestly thats the only difference Ive noticed. Engine still revs wicked fast.
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Old 04-28-2008, 11:39 AM   #23
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Put a 2.0 pulley on the front of your 2.5 if you want a lighter pulley that still has harmonic dampening capability... It weighs about half as much...
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Old 04-30-2008, 09:52 AM   #24
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Im running a perrin lightweight crank pulley with ACT streetlite flywheel also the motor is built and the internals are lighter and I have no stalling or cels.
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Old 04-30-2008, 02:41 PM   #25
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Quote:
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And don't you think nascar would be using them if they were better?

That's hilarious
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