Any interest for an oem weight twin disk flywheel?

[Whitbread]

Hello guys, trying to gauge any interest here. I'm not a huge fan of lightweight aluminum flywheels in daily driven street cars. I'm going to make at least 2 steel flywheels that will be setup for the ClutchMasters FX850 twin setup. I'm a dealer for CM and will make a very attractive deal on the package with the steel flywheel if anyone wants one and will do a run of 5 or 10 if there's enough demand. The FX850 setup is about 12 pounds lighter than the stock clutch and flywheel with the CM aluminum flywheel. I will see what the cad model says for weight, but my target is to match oem or even go slightly heavier. Friction surface will be replaceable, so that feature of the aluminum flywheel will remain. Flywheels will be CNC made of US sourced 1045 steel and made in Hillman, MI.

Here's the alum FX850 flywheel

 

[Steven@ClarkPerformanceFab]

Cool idea man. I was looking into the CM FX850 last year before I bought my MFactory. I know the two most popular twin discs on this platform are the Spec and MFactory but the FX850 is an absolutely amazing clutch and I’m interested to see how it would perform. I would much rather go with that when my current one dies. Any estimate on pricing for a clutch/steel flywheel combo?

 

[Manic Mechanic]

You've never driven a street car with an aluminum flywheel have you? Otherwise you'd be a fan. Just saying. I would never add weight to a flywheel, might as well hang a parachute on the rear or disconnect a coil. I have put aluminum flywheels in four high performance applications with nothing but better driveability and performance, enough to be favorite mod type results to many. Once the car is moving from a stop, any flywheel weight is a handicap to acceleration. Now if you're going to hitch a camper to the car, sure go for more flywheel. It will help get you going uphill.

 

[ccbsecu]

Any reason to favor a steel flywheel for high whp/wtq builds? As compared to aluminum?

 

[Whitbread]

You've never driven a street car with an aluminum flywheel have you? Otherwise you'd be a fan. Just saying. I would never add weight to a flywheel, might as well hang a parachute on the rear or disconnect a coil. I have put aluminum flywheels in four high performance applications with nothing but better driveability and performance, enough to be favorite mod type results to many. Once the car is moving from a stop, any flywheel weight is a handicap to acceleration. Now if you're going to hitch a camper to the car, sure go for more flywheel. It will help get you going uphill.

I absolutely have, and that's why I said I'm not a fan for true daily driven cars. You said yourself, "once the car is moving". That right there is one of the main downsides to a lightweight flywheel in a car that gets stuck in traffic driving in my opinion. Faster acceleration isn't worth much if the car is annoying to drive (compared to oem) on a daily commute. I'll leave the on/off, easy to stall, terrible to daily drive clutch setups to to broke college kids playing with 1990's CRX's "becuase race car!". True race cars, sure, run a 4.5" triple disk clutch with a 5lb skeleton flywheel. My version of a nice street car is one where anyone can hop in and drive without a 10 minute lesson on how to drive the car and what "weird" behaviors are normal.

I may be a new guy to the N54 platform, but I've built one or two things that go fast. This is a Lotus exige with 434" Katech LSX and twin EFR 9180's.

Any reason to favor a steel flywheel for high whp/wtq builds? As compared to aluminum?

It depends on what your goals are. For 1.8T Audi A4 drag guys, I actually make a 30lb billet steel flywheel that makes a huge difference for getting an AWD car on slicks out of the hole. The extra stored inertia helps to keep them from bogging when the clutch is dumped at 5+krpm.

In a street application, while the aluminum flywheel accelerates faster, the inverse is also true and somthing many people forget. When you push the clutch, the rpms drop faster and it's harder to make a perfectly timed smooth upshift when you're not driving like you stole it. The other difference is the larger mass will dampen torsional vibrations better at idle to reduce gear rattle in neutral.

 

[ccbsecu]

I also believe it is specific to the application. IIRC - this clutch (pictured) and flywheel will be used in a E8X N54 with a 6870 turbo, built motor and head, full suspension upgrade (solid drive shaft, race axles, diff brace, diff and sub-frame bushings, control arms/trailing arms, coliovers, etc...)

Hard launching isn't really the purpose of the build. Possibly the occasional hard launch, but standing and rolling 1/2 mile events are likely what it'll see.

 

[doublespaces]

It depends on what your goals are. For 1.8T Audi A4 drag guys, I actually make a 30lb billet steel flywheel that makes a huge difference for getting an AWD car on slicks out of the hole. The extra stored inertia helps to keep them from bogging when the clutch is dumped at 5+krpm.

Interesting, is there more information on this before/after?

 

[ccbsecu]

I want more details on that Lotus!!

 

[Manic Mechanic]

To each their own. The only place I can see maintaining OEM flywheel weight or increasing it would be in an application with inadequate low end torque and a heavy chassis with steep gearing. Then the flywheel is needed to keep the driveability. If you have the torque to get rolling, and most cars have more than enough, there's little to none "weird" lessons to learn, in fact in most "performance" cases where power is excessive a lighter weight flywheel will improve driveability and control. You may have different experiences, I have no problem with that but it's not common.
If you want to launch an AWD on slicks with inadequate performance gearing you should retain flywheel weight. But expect to break things in the driveline when done. A better approach would be to regear appropriately and using the slipping ability of a clutch to launch it.

I won't interfere with your post anymore, you know what you want and good luck to you. I would go in a different direction.

Vernon

 

[Whitbread]

If lighter was better for everything, why is MFactory's twin flywheel 21lbs instead of 10lbs like the CM aluminum one is? Why not just run a triple disk setup like this in every street car out there?

For the people that want every ounce of performance regardless of compromises in street manners, those options are out already out there. I'm looking to provide an option for the people that want a 600+whp sleeper street car with as close to stock driving smoothness as possible.

I drew the steel flywheel last night and solidworks says I can get a maximum of 29.9lbs out of it. That makes it about 8lbs heavier than oem and 20lbs heavier than the aluminum CM flywheel. I can cut into the backside to make it oem weight or a little less if requested.

Interesting, is there more information on this before/after?

I don't have any numeric data, just feedback of "The car gets out of the hole way better going from the 14lb flywheel to the 30lb".

I want more details on that Lotus!!

I sadly didn't get to see it run, but I did get a video from the dyno operator of the car flat lining a 1600hp rated dyno on e85 at 32psi.

 

[doublespaces]

So do people HAVE to buy a whole clutch kit or can they just bring their own clutch? How much money are you talking?

 

[Whitbread]

So do people HAVE to buy a whole clutch kit or can they just bring their own clutch? How much money are you talking?

I have 2 versions of the flywheel in soldworks currently. Version one is essentially a copy of the CM flywheel that is currently being sold for the N54 and is backwards compatible with any fx850 kit out on the street. I'll happily sell this flywheel alone with a new friction surface, pilot bearing shaft, ring gear, and arp crank bolts for somewhere between $500-600, waiting on the exact quote to come back from my cnc shop. Just tell me what weight you want.

Version 2 of the flywheel has a couple changes to use a thicker replaceable friction face and use two sprung disks instead of one sprung/one solid as the fx850 setup currently is. With double sprung disks and an 8lbs over oem, I'll put money that it will the nicest street mannered twin kit available. My target is to keep this option with fx850 kit between $2000-2200. If there's anyone local to me that has a well built up car, I'll happily offer the kit at my cost with free install in exchange for a long term review.

 

[ccbsecu]

Not to hijack this thread - but Whitbread is also a Wavetrac dealer, Powerflex dealer, etc... He makes the LSD's in house, send a donor core diff - he will even add a proper drain plug. I know him personally and his work is simply amazing.

@doublespaces - This is the guy building my M57.

 

[doublespaces]

Not to hijack this thread - but Whitbread is also a Wavetrac dealer, Powerflex dealer, etc... He makes the LSD's in house, send a donor core diff - he will even add a proper drain plug. I know him personally and his work is simply amazing.

@doublespaces - This is the guy building my M57.

Awesome, can/will he machine a welded diff? I've tried to setup Wavetrac group buys before. Nobody stocks any cores so it never happens.

 

[Whitbread]

Awesome, can/will he machine a welded diff? I've tried to setup Wavetrac group buys before. Nobody stocks any cores so it never happens.

Yes, thats my specialty actually. I can do bolted ones too, but the welded are what requires significantly more expertise. I posted a thread here in the vendor section advertising my services, but apparently no one read it and it fell into the depths of the internet.

I cut the ring gears off in the lathe with ceramic tooling, drill and tap them in the mill on a rotary table, check measurements against gauge block set made from oem diff before ring gear was cut off, and when dimensions match, I reassemble in the oem housing and ensure backlash is the same as the diff arrived with. I also add a 1/4" npt drain plug so you can actually change the fluid.

 

[ccbsecu]

What we have done in the diesel group - a couple people buy donor cores and then send them to Matt for the Diff. The next guy up for the diff buys the core from the the new owner of the swapped LSD and it’s sent directly to Matt. Rinse and repeat. No down time for the end user.

 

[doublespaces]

I've got a spare 3.46 diff. I bought a core for my last LSD. How much do you charge for the welded ring gear machining?

This was your thread, it didn't have enough photos

https://bmw.spoolstreet.com/threads...uamist-and-custom-fabrication-machining.1879/

 

[Itsbrokeagain]

what would it take to make something like this at the factory weight, say 22lbs or whatever it is? I have a Spec Steel flywheel in my clients car and I love the way it feels, Ive seen aluminum wear out too quickly on the street, especially with lots of stop and go driving.

 

[The Convert]

I would love to see this thread moved to the N54 section. Would get way more views and invite a lot more discussion and sales. This guy definitely sounds like he knows his shit and is just the type of vendor we need more of around here.

 

[ccbsecu]

@doublespaces - I agree with @The Convert