Replacement Flexplate

During my latest build we found that my flexplate has a crack between two of the teeth so my question is what aftermarket SFI 29.1 flexplates have people used ?

I have a 4L60 with a PI 3200 converter and I'm not sure which flexplates will work.

I've kind of found that a lot people use the TCI flexplate model 399753 with LSx motors. From what I've read it's heavier then OEM but that the extra weight give it an advantage launching. But I've also read that lighter, aluminum flexplates like the one made by CRS are better but I also have read that the lighter flexplates only had a benefit on road courses not drag strips. Meziere FP319 - Meziere True Billet Flexplates are also supposedly pretty well thought of but cost more.

There is another manufacturer called CAT that a good number of people seem to use ... well because it's cheap. That flexplate is made in China and use to sell on ebay for $70 shipped. It is now being rebadged under other brand names. My thought on that is steel from China though with SFI rating of 18.1? as described in the product description on the CAT web site. 18.1 is the specification for Crankshaft Hub Harmonic Dampers. lol Now I can see why its only $70 ... If they can't even bother to get the product description right it's probably not something I want to be sitting on top of. ...oh and I just found some posts from people saying they have had the CAT and the starter broke teeth on it ... I mean WTF???

"NHRA Requires this on 9.99 or quicker ET cars, and 135 mph or faster cars meeting SFI Spec 29.1" The other flexplates I've looked at all meet this.


I initially was leaning towards the lighter CSR 200 AL-LS ....but it looks like it may longer exist on the CRS web site and as I investigated I got more info on the benefit of a heavier one.

Here's what I'm seeing in quite a few places abouth going to a heavier flexplate, both manufacturer sites and various forums.

"heavier than a stock flexplate which creates inertia force. The inertia force is designed to provide quick launches, lower reaction times, improved 60 foot times and more constant engine RPM's during shifts."

Also read this:

A flywheel or flexplate does not consume power. It is a rotating mass which stores energy. A heavy flywheel/flexplate will store more energy. That means the engine will not spin up as fast, but once it's there will tend to stay there longer. A light flexplate stores less energy, so the engine will run more roughly at low RPM since there is less smoothing of the rotation between cylinders firing.

If you need to get the RPMs up faster, go with a lighter flexplate. If you want to keep the RPMs up while shifting at WOT, use the heavy flexplate. But as FF2 said, there is likely little difference in weight since it's a flexplate and not a flywheel. Most of the mass is in the torque converter and fluid in the converter.

Now here's an interesting one I found that also says adding weight is a good thing.

It's an Aluminum flex plate that can have weight added to it by using an Inertia Weight Ring. My question is why bother to get a light weight flexplate ... then add weight to get the benefit of a steel flexplate other then to be able to add a specifc anount to dial in on the best weight?


The Reactor Products original aluminium flexplate is precision computer machined from solid billet aluminium, is SFI approved and comes with replaceable Starter Steel Ring Gears.

National event winners, world champions and record holders have found proven performance and unsurpassed quality in the Reactor Products Aluminium Inertia Flexplate. Call today for personalized assistance in selecting the reactor inertia ring setup best suited for your needs.

REACTOR PRODUCTS VARIABLE INERTIA FLEXPLATES...


Gardena, CA - Now you can replace the breakage-prone OEM Chevrolet flex plate with a precision Reactor Products Variable Inertia Flexplate and gain the performance advantages of "stored energy".
Here's How:

First, you've probably come to know the problems associated with using the stock Chevy Flexplate in high performance applications. Because of its construction (.90 - 110" steel stamping with a tack welded ring gear). It commonly suffers from misalignment, excessive run-out and outrigh breakage.

The solution comes in the form of a precision computer machined solid billet aluminium flexplate. These units are reinforced in all critical areas, and by the use of special "lightening slots:, are comparable in weight with the OEM flexplate.

However, in many applications, weight properly placed can actually benifit performance. And that's why a special Inertia Weight Ring is offered. The weight ring is easily bolted to the rlexplate as desired, and because the weight is concentrated on the outside (as opposed to the hub area), it takes full advantage of gyroscopic forces to provide "stored energy" on the launch.

Moreover, the weight ring serves to sgnificantly reduces RPM drop-off between shifts, which keeps the engine closer to its optimum power band.

The Reactor ring set-up had proven to be an excellent benefit to those racers with smaller displacement engines, but is equally at home on engines of any size.

The Reactor Flexplate and Inertia Weight Ring come dynamically balanced and are available for small block and big block Chevy (153 and 168 tooth) applications, Buick V6, Mopar & Fords.

And the winner is .....

http://i2.photobucket.com/albums/y26/GTO1/IMG_0820.jpg

FP319 - True Billet Flexplate

These plates are clearly the superior choice for quality and precision. Machined to exacting tolerances from 4340 round bar, our proprietary manufacturing process ensures the strongest gear tooth, least runout, and the best longevity on the market. All of our flexplates are certified to SFI 29.1.

Features of this part number include:

•Concentric machined to .005
•One piece design - 100% machined
•Proprietary heat treating process
•Chamfered gear tooth provides better engagement

Application information:

•Fits GM LS-1 through LS-8
•168 tooth ring gear
•12 pitch tooth profile
•Neutral balance
•Weighs 6.95 pounds
•Converter pattern 1 - 3 holes 7/16" diameter on 10.75" bolt circle
•Converter pattern 2 - 2 holes and 1 slot on 11.056" bolt circle (stock LS configuration)

http://i2.photobucket.com/albums/y26/GTO1/IMG_0818.jpg

http://i2.photobucket.com/albums/y26/GTO1/IMG_0819.jpg

...thank you Amazon.com for a killer deal on this. lol

Very nice Russ, glad to see a real hotrodder back!!!!

Just ordered a Hays SFI-approved flex plate for our car. I don't think the 2-3 pound weight gain over stock is going to make a noticeable difference in how the engine revs. To me, it is simply a safety and reliability issue.

Quote:

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Originally Posted by pajeff02

Just ordered a Hays SFI-approved flex plate for our car. I don't think the 2-3 pound weight gain over stock is going to make a noticeable difference in how the engine revs. To me, it is simply a safety and reliability issue.

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I won't notice any gain since this is going on a new ERL 427 shortblock. I'll have a crazy amount of torque so the launch may not need to benefit but if the extra weight keeps up the RPMs on shifting at WOT I'll take it.

I agree on the safty issue ... that's one thing that sold me on the Meziere. I was impressed with the one piece design.

Quote:

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Originally Posted by GTO1_OHIO

I won't notice any gain since this is going on a new ERL 427 shortblock. I'll have a crazy amount of torque so the launch may not need to benefit but if the extra weight keeps up the RPMs on shifting at WOT I'll take it.

I agree on the safty issue ... that's one thing that sold me on the Meziere. I was impressed with the one piece design.

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Will you be posting some pics of the build?

Quote:

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Originally Posted by pajeff02

Will you be posting some pics of the build?

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Certainly

As always very nice right up,you will be happy with the peice,im running a heavier flexplate on my 540 merlin motor,even though your new setup will have a big advantage in power always a good thing to make the little things count like the flexplate on a heavy car ,as well all know the launch is a deal breaker at imes in racing!