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Discussion Starter · #1 ·
Well I got the Exedy lightened flywheel installed w/ the 2nd generation Subaru OE clutch setup. The dealers weighed my old flywheel which came in at 23lbs and the new one is 13lbs. I picked up my car last Fri afternoon and everything seemed fine however the dealer disconnected my battery so I lost all of my ECU learned driving behavior. So I felt that the ECU needs to learn my driving behavior again but in a more timely fashion so yesterday I decided to go do some nice mountain runs. I turned on and off the car after each run to let my driving style set in. I put on 350+ miles in less than 36hrs. :) I did get 6+ gallons of gas from a "cheap" place to get by because it was the only one around however I "think" have already used up all of the cheap gas since I have since filled up at a Chevron. Well today I go to church and as I'm coming back home I decided to stop at a local store to do some shopping. I drove about 15-20 minutes on the hwy so the engine is hot. I'm in the store for about 10-15 minutes and come out to the out ... this is the weird part.
I start the car and it stalls? I start it again and it stalls. I start it again for the 3rd time and it stalls yet again. I'm panicing now since it never happened before. I noticed that everytime during each of the 3x stalls that the tach would go up and then fall to low and just stall? On the 3rd try I hit the gas and the engine was fine but as soon as I let off the gas the engine stalled. I gave someone a call and asked about this situation because it's totally new for me. He stated that a lightened flywheel "can" cause stalling + the factory ECU is still "learning" the new flywheel. I drove home and turned on and off my car and it seems fine again? Weird. :(

Questions:
1. Could the flywheel cause the stalling?
2. Why is it happening now instead of on Fri ... I would think it would have happened earlier?
3. How can it be rectified?
4. Will the factory ECU ever really learn the new flywheel?

Please help. Thanks. :(
 

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I do know that people have had trouble w/ lightened flywheels causing stalls because there is less inertia in the flywheel keep the engine running.
 

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Discussion Starter · #3 ·
Humm ...

No one told me the possible "problems" of a lightened flywheel until today which is after the fact. :( Well I drove my car many times since this afternoon and turning it on and off and the problem has NOT come back. Weird, weird, weird. I hope it NEVER comes back. If it does I'm gonna cry. :(
 

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Stalling with a lightened flywheel refers to the fact that with less
rotating mass, it is harder for the engine to get the car moving.
So if you launch the car the same way after installing the new flywheel, the car might stall. You have to spin the engine higher when letting out the clutch.
the stalling issue is unrelated. hopefully you are right and it was bad gas. if you feel this was the cause, i would get a couple cans of good quality fuel injection cleaner and run it through a couple tankfuls of gas.
 

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Judging by your symptoms, it seems like a batch of bad gas is more likely the issue. Lightweight flywheel will NOT cause stalling unless there is a tuning issue that is not done correctly or properly. We install MUCH lighter flywheels than the comparitively heavy Exedy with absolutely no stalling problems at all. Lightweight flywheels causing stalling is usually due to tuning issues which may not manifest itself with a heavier flywheel but which do rear their head with a light one. Tuning the fuel and timing curves more precisely solves the issue. We've seen this on the Toda flywheel when running too rich. Slight stalling issue when coming off the highway. After dialing back the fuel and playing with timing, absolutely no problem. This is on a highly modified car though. On a mildly tuned car you will not have to mess with this.
 

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Discussion Starter · #6 ·
Yo

Could the "bad" gas happen today even though I went through the whole tank yesterday? I was thinking the "bad" gas came from the little gas place near Helen however the Chevron which I filled up w/ last night shouldn't have any problems? Also will the UTEC be able to solve this situation for idle? I read that the UTEC does NOT mess w/ the idle and leaves it up to the factory ECU? The more I think about it the more I can justify an aftermarket ECU because waiting like 1+ weeks for the factory ECU to "learn" my driving style is killing me ... I want power NOW ... not 1+ weeks from now.
 

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Discussion Starter · #8 ·
Humm ...

Well it seems to me that my REX is just weird sometimes ... maybe it's just being lazy. :) Well it's been fine since yesterday ... I'm just surprised I the flywheel didn't make as big of a difference as I expected. :( I guess I'll need to take some GTech readings to make sure. ;)
 

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A lightened flywheel is not a big horsepower mod. It is a complimentary mod that will help your engine to spin a little more freely, and one which I would perform AFTER the obvious mods like engine management, fuel, turbo, etc.

-Pace
 

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Re: Humm ...

chuglobal said:
Well it seems to me that my REX is just weird sometimes ... maybe it's just being lazy. :) Well it's been fine since yesterday ... I'm just surprised I the flywheel didn't make as big of a difference as I expected. :( I guess I'll need to take some GTech readings to make sure. ;)
Go for a lighter one and it makes a bigger difference. Jim should be getting his ATS carbon clutch in the next day or two and he'll tell you how crazy fast the car will rev soon.
 

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Discussion Starter · #11 ·
Umm

A lighter what?
 

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Re: Umm

chuglobal said:
A lighter what?
I believe that he's referring to an even lighter flywheel. He mentioned in an earlier post that they install much lighter flywheels than what you have installed. The whole idea of a lightened flywheel, as Pace said, is to improve the revving (i.e. faster revving) of the car to get it into boost more quickly. It is generally done after other mods (turbo, etc.), but that doesn't mean you can't do it whenever you want, of course.
 

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markmiller said:
Stalling with a lightened flywheel refers to the fact that with less rotating mass, it is harder for the engine to get the car moving.
Actually, with less mass, it's easier for the engine to get the car moving. That's the whole point of using a lighter flywheel.
 

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lyonsd said:


Actually, with less mass, it's easier for the engine to get the car moving. That's the whole point of using a lighter flywheel.
I believe that markmiller is saying that the system with less mass has less inertia and thus stalls more easily, indicating that it is more difficult for the engine to get the car moving (in other words, when the clutch engages, it robs revolutions from the flywheel due to friction and thus would stop it more easily with a REALLY light system compared to a REALLY heavy system). Whereas, with less mass in the system, it revs higher more quickly, thus causing the car to get into boost more quickly (for FI cars, obviously) which creates the a "faster" car. I hope that made sense....
 

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I realise this thread is REALLY old, but the same thing just happened to me twice today on two different occasions (same exedy flywheel). Both after a highway drive. I left the car at idle and it stalled. My UTEC hasnt been tuned in a while, but I'm going to the shop on friday, and i'll throw it on the dyno, as I'm running a little rich. Hey CHUG, did you ever resolve the issue with the flywheel?
 

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The same thing happened to me like a week after installing my exedy flywheel. It happened twice and then i gave the car a bit more gas when I turned it over and it worked. It hasn't happened since :confused:
 

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Well, the time table is the same here...a week. Although, I didnt have a problem starting it, it just stalled after idle following a drive on the highway, almost like a turbo timer would. It seems like this is common and goes away, lets hope so...I'm still going for a dyno tune friday when i install my stoptech's and mount my volk's with some ghetto fender rolling. I'm a little rich right now.
 

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My combo does the same exact thing also. I give it a bit of gas and its fine. I dont find a problem with it.. A little annoying but no problem. I havent been tuned in some time also..I go at the end of the month.
 

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Discussion Starter · #20 ·
Yo

Humm, I have to think back as it was more than a year ago. :) Actually I got rid of the flywheel and a tranny problem occurred and the dealer blamed the flywheel. It's a whole other issue but I was tired of dealing w/ variables I couldn't control, I "only" mod my car now when it's in my garage w/ a person who I trust doing the work.
I never found the answer to the stalling problem. I only had the flywheel for a little more than a week.
 
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