I'm more than likely going to need a knew clutch setup in my car so I thought I would get a clutch and flywheel combo. Which one of these combos would bebest for drag racing and some spirited street driving?

The SR Motorsports 9.5 lb alluminium flywheel with counterwieght, hardware, bearing kit, and ACT street/strip clutch for$799.

OR

The Racing Beat 12 lb alluminium flywheel with counterwieght, hardware, and ACT street/strip clutch (from RX7trix) for $741.

I know that a lightened flywheel will help me, but I was wondering if the 9.5 lb flywheel was to light for daily driving and drag racing? Also if there is a representative from SR Motorsports on here could you maybe give me the 11 lb flywheel instead of the 9.5 lb one for the same price? Just asking. Anyways, any advice is really appreciated. Thanks.

I have the 9.5# unit and it is great for spirited drivng. Daily driving is not an issue either. It won't affect your idle or stall out on you like some might say. But it is not good for drag racing. The 12# unit might be more for your taste. It's a compromise anyway you cut it. The stock unit would be best for drag racing, as it's the heaviest. The 9.5# lets the revs climb and fall a helluva lot faster than the stock unit. It's your call in the end https://www.nopistons.com/forums/pub...IR#>/dunno.gif .

lighter flywheels store less energy so it can be annoying for drag racing, but it really is not that bad, it will hurt you right off the line but after that it improves acceleration significantly... so it would be beneficial either way... and I was able to shift more quickly with the aluminum flywheel since the R's would drop quicker.



But the difference between the 9.5# and 11# and 12# is probably very minimal, it really depends on where the weight is in the different flywheels... They should say the flywheels moment of inertia, not just the weight, since that's what really matters.

annoying.

Well I just talked to a good friend of mine, who I thought had the 9.5 lb flywheel. Turns out he has a 17 lb steel flywheel. He said the alluminium ones are not meant for drag racing because they warp too easily. Have any of you had this problem? Does anybody know where I can get the 17 lb steel flywheel at as combo with a clutch? Thanks.

Aluminum warps too easily? That's a new one on me. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

I just guess it depends on how much you are into drag racing. Sounds like you want a well balanced all around car. I'll tell you what, once I had that 9.5# badboy in there it was happiness after that. pengaru is correct. It does accelerate quicker. You car will feel a couple of hundred pounds at some points. The engine will feel like a what a sports car engine should feel like. Try it, you'll like it. You car should still be deep in the 13's (I guessing by your mods)



BTW 7mech, do you get boost creep?

Yes I get boost creep. Sometimes I hit about 12psi on cold nights. Most of the time it doesn't go above 11psi. I also fall back down to about 7psi at about 6k rpm. How is the 9.5 lb flywheel for everyday driving. Is it a pain in the ass or is it only a little bit of a change? What I meant was they tend to warp do to the excessive heat that standing lauches create. Is there any truth to that?

Whoa, you get less creep than I do. Duh-oh!



There might be some truth to that, with the warpage from the abuse like that. But you'll also kill clutches as well when you do that. (So I went to a doctor and told him it hurts when I do this: https://www.nopistons.com/forums/pub...R So he told me not to do it.) You could look at it this way: there's probably less heat made from the clutch trying to slow down the flywheel. Less weight to stop in an instant. I've had mine for over a year (about 8k miles however - I live a mile from work) and it's still as stong as day one. I abuse it on an almost daily basis plus tons of autoX'es thrown in for good measure. It's still good with 265rwhp (I still need to scan that dyno sheet https://www.nopistons.com/forums/pub...DIR ) day in, day out.



The flywheel from SR Motorsports isn't all aluminum. It has a steel ring gear and steel friction plate. Both parts can be replaced if for some reason they fail/get worn out.



Daily driving is OK. It took me a few miles to get used to it. It suits me fine and I'll never go back to a heavy one. Starting from a dead stop after sitting at a red light on a steep incline isn't too dramatic. Just feed it a few more revs. It'll become instinctive to you.

Yeah I called around to a few shops today and got the skinny about them. All the guys I talked to said not to get one for drag racing. They said that because they are so light they don't help youwith your launch and aren't worth it. They all recomended that I stay with my stock flywheel. I think I'm going to save my money and stay with the stock flywheel. Thanks for all the info though.



BTW what year and model car do you have? I think you get more creep and drop off of boost with the more HP(with stock turbo).

It's an '89 T2. Blitz SUS intake, no TID yet, and a full 3" exhaust. Even with the Profec B set low (9# on low setting), it goes up to 15#. With the bolt-in silencer tip plugging the exhaust I can control it.

Try adjusting the sharp and mild knob on the controller. That on cotrols how quick your wastegate opens. I think mine is set on full sharp(not sure because my car is at the shop and I can't look at it). I just looked at the Profec B instruction manual and by doing that I culd tell mine is set at full sharp. Also check to make sure that you have the selector setting(numbers with pins on back of controller) set at 4 down, 3 up, 2 up, 1 down (actuator type when overboost occurs). This should solve the problem or atleast get it close to where you only overboost 1 to 2 psi depending on air temp. Do you get alot of overboost in 4th and 5th gears?

BTW I'm assuming you have an internal wastegate and are running the stock(or something close to stock) turbo.

The Racing Beat aluminum flywheel is 8.2 lbs, and the total weight increases to 12.5 lbs when you add the counterwieght and hardware. It also has a replaceable steel friction surface (that is included in the 8.2 lbs weight I quoted). If the weight for the SR flywheel is just for the flywheel itself, expect the total weight to be 13.5-14 lbs. I really like my light flywheel, but it might be better to go with the stock flywheel or the RB 17 lbs flywheel if you want to drag race the car. A light flywheel will increase your launch RPM substantially and make the car harder to launch. I haven't heard of people warping aluminum flywheels, but the added inertia of a heavier flywheel seems to be easier to launch and better for drag racing generally. I still don't know if the energy stored up in the flywheel at launch (more inertia = more stored energy) is a significant factor, but ease of launching alone makes the heavier flywheel better for drag racing, in my opinion.



The light flywheel makes the car rev faster and frees up a good bit of power in first gear (50HP?), and a little power in second (15HP?), but after that you aren't accelerating fast enough for the difference in inertia to give you any significant increase in power at the wheels (<5HP?). The light flywheel also makes it easier to match revs for downshifts (heel & toe), and it matters much less if you don't match them right.



-Max

Holy moley! Look at the big brain on maxcooper. Yeah, I believe you with the power numbers in the higher gears. But subjectively if feels a lot better. The butt-o-meter never lies https://www.nopistons.com/forums/pub...#>/biggrin.png (or is that the magic eight ball that never lies?)



7mech: you're on the money. I basically have a stock setup. I'll try your advice the next chance I can. :bigthumg:

Jerk Racer: Cool let me know if it works for you. Oh yeah you must remember that I live in Texas and generally the temps stay higher and that my distance above sea level my be different than yours. These factors may affect how your car boosts.



Maxcooper: Thanks for the info. I think I'm going to stay with my stock flywheel because I have yet to road race my car. I may sometime in the future, but untill that day comes I think my stock flywheel will suit me just fine.

Well, I had all the switches set as you suggested but the mild/sharp knob was set to the middle. I haven't been able to test it out yet. I will tomorrow. Over here near Seattle this time of year the weather is really good for turbos. I'm also at a very low elevation.

Cool, again let me know how it works out.

i drove silver 93's FD with 9lb flywheel. its nice but i wouldn't invest in a LW flywheel unless you have $$$ to burn or your flywheel has cracks. i have the stock flywheel in my FD and a 17lb in my old TII, it revs more than fast enough for me https://www.nopistons.com/forums/pub...DIR#>/wink.png

https://www.nopistons.com/forums/pub...IR#>/boink.gif that is because you cant drive

Vosko would you say the 17 lbs Flywheel is better than the stock one and worth the investment. A friend of mine wants to know the order of mods he should do his TII in. We're at this point now.

if he has the money its a nice mod to do but its not necessary...........

the aluminum flywheel made my car a completely different animal. I love it, but it isnt the best choice if you want optimal drag racing performance, launching will be more difficult.



It also depends on what kind of clutch you have, if you have a puck style with no springs the aluminum flywheel might make daily driving difficult. I have a street/strip HD clutch from RB, and it's very driveable. The car revs like a demon, let the rotary free ditch that anchor of a stock flywheel :P

Maybe im dumb but how does a lighter flywheel affect launches?

A flywheel with a higher moment of inertia (which is usually true for heavier flywheels, but it really depends where on the flywheel the mass is concentrated), will have less tendency to bog when you launch, because more energy is stored in the flywheel (greater inertia at n rpm than another flywheel with a lower moment of inertia (light one), at n rpm.).



Think of it this way, you have two vehicles, all things equal, except one has twice the mass of the other. Both vehicles are traveling at the same rate, which one can slow to a stop in a shorter distance (lets assume traction is not an issue)? The lighter one.



Well, when you go to engage the clutch on your motor, the lighter the rotating assembly (rotors, counterweights, flywheel, pressure plate...) the less inertia there will be (usually), so it's easier to bog the motor. Lighter flywheel usually requires leaving from a stop at higher RPM than the stock flywheel to compensate for the lost inertia. This becomes exaggerated if you have also upgraded the clutch to a quick engagement type with little damping and a beefier pressure plate.



For drag racing, the light flywheels are great for acceleration, but can be more difficult to leave the line with. But rotary engined vehicles usually leave the line @ the strip at high rpm anyways, at least the serious ones do... anything > 6k and the light flyhweel is definately not going to pose any problems with bogging. But to launch like that you need good hot rubber before you run. If any of you have seen crispeed 1/4 mile movies, thats how you really launch an rx-7 https://www.nopistons.com/forums/pub...IR#>/smile.png



imo light flywheels are great, and make the car alot more responsive and fun to drive. The stock FC flywheel is heavy enough to be a boat anchor.

the stock FC flywheels are very heavy. the FD flywheel is pretty light from the factory though.....

I think FC flywheels are from 24-28lbs hefty!

i say the 17lb flywheel is just right weight wise. i don't see a need for a super light flywheel lol

the fc flywheel is pretty heavy, I've lifted one and I was surprised, it didn't look nearly that heavy.

Is it possible to remove some of the weight from the flywheel with a milling machine or lathe. Maybe remove likek2 lbs from the outside of the wheel or would that compromise strength?

ha ha Node is George W on the other forum and some chick on this one. RX7club is down AGAIN!!

for drag racing a stock flywheel is best. for road racing a light flywheel is better...