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  3.4L P/R.... Built! Looking to do vortech SC someday.. Aluminum or steel flywheel?

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3.4L P/R.... Built! Looking to do vortech SC someday.. Aluminum or steel flywheel? by unboundmo
Started on: 03-06-2015 04:06 AM
Replies: 5 (233 views)
Last post by: Patrick on 03-07-2015 02:56 PM
unboundmo
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Report this Post03-06-2015 04:06 AM Click Here to See the Profile for unboundmoClick Here to Email unboundmoSend a Private Message to unboundmoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just looking for your inputs...

I have a built, forged internals and all the goodies.. I was looking to go turbo eventually but now a Vortech Super charger in the a/c area looks pleasing to me. I bought the billet steel flywheel originally but I had it decked a few to lower the weight some. If I remember correctly, it weights about 11 lbs now vs the 12 from factory.. It is from the Fierostore originally when they sold it and is a Ram manufacture billet steel. I'm also running a 9-11/16" pressure plate and clutch from clutch masters on it..

I've heard that running a little heavier flywheel would help with keeping the momentum up in inertia allowing the turbo not to work so hard during shifts.. I've also heard that aluminum comes down quick in rpm during shifts but quick on the get go... What's your thoughts?

I have the engine torn apart and can easily change if I want...

For those who have the aluminum, what's your thoughts.. Pros and cons.

What do most prefer?

I have an 88 so it'll be a neutrally balanced flywheel.. The engine has been knife hinged and balanced during the first rebuild.. Will changing the flywheel mess that up? I wouldn't think it would but just curious...

Thanks for your replies

[This message has been edited by unboundmo (edited 03-06-2015).]

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Neils88
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Report this Post03-06-2015 06:17 PM Click Here to See the Profile for Neils88Click Here to Email Neils88Send a Private Message to Neils88Edit/Delete MessageReply w/QuoteDirect Link to This Post
Aluminum flywheels allow for a slightly faster revving of the engine and better acceleration, but tend to be a little harder to drive with (you'll notice it in stop and go traffic). Is this a daily driver or will you be at the track?
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unboundmo
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Report this Post03-07-2015 03:39 AM Click Here to See the Profile for unboundmoClick Here to Email unboundmoSend a Private Message to unboundmoEdit/Delete MessageReply w/QuoteDirect Link to This Post
I usually just drive it several times a month.. It's the fun car that gets out only on nice days.. I live in Cali so trying to avoid traffic depends on when I get it out.. A very good chance I'll get caught up in the traffic.

So can you elaborate on the different feel of it? I like the fact of a faster spool up.. Would you say because of the lighter inertia movement doesn't feel solid..in a way? Where the heavier flywheel keeps this more of a solid feel of the rotating mass?

[This message has been edited by unboundmo (edited 03-07-2015).]

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Patrick
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Report this Post03-07-2015 03:52 AM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post

Make sure you investigate the issue of "aluminum creep".

Someone who knows a lot about this (and how to prevent it) is fieroguru.
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unboundmo
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Report this Post03-07-2015 01:38 PM Click Here to See the Profile for unboundmoClick Here to Email unboundmoSend a Private Message to unboundmoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:


Make sure you investigate the issue of "aluminum creep".

Someone who knows a lot about this (and how to prevent it) is fieroguru.


'O MY GOSH Patrick.. Thanks for the heads up! Forget that aluminum.. I'll stick to my lighten steel.. I want NO worries of things coming lose even if I install it correctly..


I saw this quote by you also...

"Geez, the more I read about this, the more reluctant I now am to buy a Fidanza aluminum flywheel for an '88 Formula I'm about to acquire (which needs a clutch). I'll be autocrossing the car, and I don't wish to be dropping the cradle every few months dealing with a loose flywheel."

[This message has been edited by unboundmo (edited 03-07-2015).]

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Patrick
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Report this Post03-07-2015 02:56 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by unboundmo:

'O MY GOSH Patrick.. Thanks for the heads up! Forget that aluminum.. I'll stick to my lighten steel.. I want NO worries of things coming lose even if I install it correctly..


I was really wanting to use a Fidanza aluminum flywheel. I thought it would give my '88 Formula an extra little bit of zip at autocross. However, I got scared off (for good reason!)... and when I replaced the clutch I stuck with the factory flywheel.

Several months later I had an occasion to exchange PMs with fieroguru, and he kindly informed me of a solution. I don't think he would mind me sharing this with everyone...

 
quote

Aluminum creep is often caused by the hole being too large, the bolt head being too small, and the material thickness being too thin at the bolted attachment. This causes very high localized pressure and room for the material to "flow" into.

If you wanted to run a Fidanza flywheel and address the creep issue, just press some thin steel bushings into the existing holes and leave them about .030" shorter than the thickness of the flywheel. The issue is the bolt holes are way too big, which reduces the area of the material the clamp force is spread against and makes it easier to "flow". The sleeves don't reduce the pressure, but they support the material and eliminate the opening it has to flow into, which will greatly reduce the chance for it to work loose.



I have no plans to drop the cradle to just swap out the flywheel, but if I had to drop it for any other issue (clutch etc), I might now consider using an aluminum flywheel with the alterations suggested by fieroguru.
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