Anyone know anything about ACT(Advanced Clutch Technology) Chromoly Flywheels? I recently saw an ad for them in a magazine and they show a picture of an RX-8 with an appplication apparently available. On their site I cant find anything besides an RX-7 Version, but I think I recall that the Flywheels in the last gen RX-7 can be used in the RX-8. Any benefits to chromoly over Aluminum?
This is the info I found on another site:
ACT StreetLite Forged Chromoly Steel Flywheel
- Counterweight sold separately
13.9 lbs
$ 239.95 Counterweight- $139.95

ACT ProLite Forged Chromoly Steel Flywheel
9.9 lbs
$265.95 Counterweight- $139.95

 

OK then....

 

^, v

 

i think the chrompoly is stronger but the aluminum is lighter. my 2 cents but you know that

 

I have the streetlite flywheel on my car it seems fine to me,
-Chris

 

the aluminum offering is simply for those who want a more responsive engine with the clutch disengaged: reducing the rotating mass of the flywheel helps your car gain a tiny bit of speed (the same as throwing out the other seats in the car, or other such weight reduction), but the main benefit is in getting an engine which can change rpm more easily allowing you to change between gears more quickly. the only disadvantage is that from a stop it can be a little harder to engage as there's less mass in the engine full of energy to help the car forward. most people who've gotten this kind of flywheel haven't reported it as being any harder at all, and the results have been universally positive.

as to why it's chromium molybdenum steel, i don't know if it's anythign beyond simply being slightly lighter than the milder/cheaper/heavier steel that comes on the back of the engine stock.

 

I would opine that the biggest difference between chromemoly and aluminum flywheels of the same weight is the serviceability of the friction plate. Most aluminum wheels have a removable surface whereas the chrome wheel must be replaced. Most users won't be hammering either wheel enough to make that an issue, though. If I had the cash I would do some testing and report back as the labor is rather easy.

Charles

 

There is more than just a little acceleration difference from installing an aluminum flywheel. On the older nonturbo rotaries, the biggest gain you could get was from the exhaust, unlike now. The second biggest, and it was close, was a flywheel. I assure you the acceleration improvement is far more noticable than just simply removing seats from the car and the responsiveness of the engine is fantastic.

 

Charles, The labor is easy????
As to the steel vs aluminum, It's hard to say without seeing the actual componants. The production of the parts is the factor. Both matirials work fine. The ring gear is machined into the steel wheel and pressed onto the ali one. Maybe it is also pressed on the steel one also, I can't tell. While it is very nice to be able to replace it, it is a lot nicer to have it made from the same piece of metal.

A comment on the wheel pictured. It would be nicer if the builder had put the same amount of metal removal into the rim and left the center holes out. The same weight but less polar moment. Just from looking at pictures though I might go with the steel wheel.

By mass aluminum is stronger then steel. It is just that sometimes it takes up a lot more room to get the same strenth. In the flywheel case there is room, just make it thicker.

The quality of the product might be the factor to decide which one you buy. Also the reputation of the vendor to back up their products. Flywheels are not hard to make and they rarely fail. But, I have it on inside information that SOME and only some, of the aftermarket ali wheels are made from poor quality imported stock. The density is uneven and balancing is a problem.

 

Richard, when I replaced my flywheel/clutch combo it really wasn't that hard especially when compared to some other projects that have yielded much lesser gains. How difficult will it be to do, say, a supercharger install? Granted, with a properly designed and tuned system the gains will be awesome but that is a 2-3 day project and it would involve special tools and a garage. I tend to view the concept of doing one's own upgrades as being a situation whereby if one needs to ask people on a website for a step-by-step process, then they should probably hire it out. Would those who have replaced their flywheels, like Broke Apex Seal and others, consider the project a difficult task? Probably not. Besides, I was pleasantly surprised to find that the transmission in the RX-8 looked the same as my old Chevy and I didn't need a manual to do the job, just metric tools and a bearing puller. A few pointers from those on this forum and I was good to go. If I can do it, so can most others around here.

Charles

 

I agree whole heart, You are right on about doing things. Doing it yourself is most of the fun for some of us, you and I included. My point was not that it was hard but that it was an undertaking that one didn't need to do every day just to find out if there is a difference between ali and steel wheels.

This holds real true if you don't have a rack and work on your back. Ryme not intended.
In fact there is a person on this thread who is going to do the work of testing my short shifter against their already installed Mazdaspeed unit. Just that doesn't require him to work under the car.

These are nice A/B tests and better yet when carried out by none invested persons.

Please keep up your well documented work, I follow it all.

Richard

 

Another long-winded and self-aggrandizing post from yours truly but here goes;

Thanks for the clarification and compliment. I really wish I had my own shop or place to do the more difficult A/B comparisons. I'd be willing to bet that the RX-8 community could use someone with mechanical abilities combined with decent journalistic skills(hint, hint) to objectively measure different products against one another and discuss their differences. TPR Mag just seems to be a bunch of re-prints from D-Sport but at least Herrera is a decent writer. The peculiar thing about performance upgrades and the aftermarket companies that provide the products is the level of seeming subjectivity involved in such matters. It's not like the laws of physics vary from one vehicle to another, so it seems simple to me to be able to reasonably predict what gains certain mods might provide. The real mystery is more along the lines of just how well-engineered the factory pieces might be. What I am getting at is that most of the math is already done. For example, I have read that to reduce the flywheel weight by 1 pound usually results in a gain around 2.7 rwhp. We on this forum have spent more time arguing over whether the number is more like 2.5, 3.0, and such, as opposed to discussing the manufacturing quality of the available flywheels out there. With this thread, we have finally come around to the agreement that a lighter flywheel has more assets than liabilities attached to it and if one is seeking a decent performance mod, the light fly is the way to go. I can tell you that using 2.7 as a basis, and several other mathemetical models, I have achieved a level of performance that I had expected all along. The formulae I use are conservative in nature so it is always a pleasant surprise to me how well the RX-8 responds to certain mods. I have boiled my experiences down to two or three of the most dramatic mods one can make for less than around $3,500 and expect to see 13 second quarter mile times, better handling, and better braking. Perhaps that is as close as we have come to an objective mechanic/journalist telling the world what has worked on the 8. My main motivation is to pass along what has worked for me and encourage others who wish to do so to begin tweaking their own RX-8's. This way we can all dispel the myth that the RX-8 is slow.

Charles

 

hey hey, be fair now, i said "like". it's essentially a bit of mass reduction, with the added benefit of an engine that changes its speed off load more quickly.

 

Charles and RotaryG are my rotary hero's...lol

 

Thanks for the props, rx8wh. Rotarygod is a very knowledgeable and helpful guy and he is the one who can take the credit when it comes to the matter of my findings with nitrous. He validated and supported many of my assumptions when I ponderd the idea and without his support and encouragement I may not have done it.

CRH

 

Chromolly is a LOT stronger than aluminum, but you won't really care until you're pushing monstrous amounts of horsepower.

Chromolly is more driveable because its a bit heavier - speaking from experience, a lightweight flywheel is NOT fun to have in your car if you have to start from a stop more than once in your drive. It basically destroyed the drivability of my Celica to the point where nobody but myself could even get the thing started.

 

has anyone added that a lightened flywheel doesn't really help when going up hill?? had a clutch masters aluminum flywheel on my mr2 turbo. it was great b/c of the quicker revs, giving me faster spool up and acceleration...but man, whenever there was a hill, i had to floor it to get to the top.

 

Forgive me for asking what may seem a noob type question. I have read pretty much all the "flywheel" threads that I can find and would like to confirm one thing and ask another.

It seems from what is being said that the flywheel forms one of the mating surfaces in the clutch assembly. Please can you confirm that this is the case.

Secondly, leading on from that, if the flywheel does indeed form one of the mating surfaces, it follows that it must be subject to wear, even if only a little. Are there any implications regarding the lifetime of the flywheel between the aluminium one, the chromalloy one and the stock one? In other words, does a aluminium and/or chromalloy flywheel have a shorter lifetime than the stock item?

And a final question that's just occured to me: will upgrading to a heavier duty clutch have any impact on the flywheel's lifetime?

Thanks.

IJM.

 

The way that aluminum flys deal with the friction surface is to have one that is serviceable or replaceable if and when it becomes too worn to provide the proper friction. The description of a particular clutch assembly as "heavy duty" usually refers to the amount of pressure that the plate assembly is exerting on the disc/flywheel surfaces. When we get to more advanced or race-oriented clutches is when we see disc designs such as 4 or 6 puck, multi-disc, or carbon friction materials. In any case, the durability of any clutch assembly is dependent on a number of factors such as the particular application, proper selection, and driver use/abuse. For most street uses up to 400 h.p. +/- a full face disc with a pressure plate listed as heavy or extreme duty should suffice.

CRH

 

ACT parts are absolute garbage. No speed shop with a conscience will allow you to purchase or install ACT parts.

Take an ACT clutch out and look at it after 300 miles, its burned around the edges.

I wish we had a part from Clutchmasters, their stuff is awesome.

 

I must be lucky because I have yet to have any of the problems cited by others on this thread. I have a 9.75 lb. aluminum flywheel, ACT pressure plate, Exedy disc, and factory incidentals. The only possible issue might be some T/O bearing noise from time to time but that is only occasionally and after I have hit 9,500 rpm's a few times.

CRH

 

I have the Racing Beat Aluminum flywheel. See below for the details. It's GRRRRReat!
http://www.racingbeat.com/FRmazda4.htm

 

I could site a few polls on forums that beg to differ but everyone is entitled to an opinion. I am just suprised how strong your opinion is. There are certainly higher profit margins in some other brands, but shops sell our parts because they work.

 

I don't get on the forums much, but I would be glad to answer any technical questions you may still have. There are a lot of misconceptions about clutches and flywheels out there. It is important to get the right parts to match the intended use.