Effects of lightweight flywheel? [merged] light weight lightened aluminum ACT fidanza

[Fryguy]

All light weight flywheel newbie threads are merged here.

I'm looking for my car to be very fast at lower speeds; my main goal is very fast acceleration. Will a lightweight flywheel be beneficial to this? Or should I just save up all my money and drop a turbo on my 84k engine

 

[Jslove1408]

Does it really make that much of a difference if you get a light weight flywheel?

Wouldn't a flywheel with more of it's mass in the center of the flywheel be more efficent then a flywheel with a lighter mass but more off the mass on the outside?

 

[paul s]

I had one(fidanza) on my car for 5 years and still works great quicker spool up, better throttle response.

 

[toecutter]

Its less rotating mass, it'll help it rev up faster

 

[Jslove1408]

But it would provide more advantages if the weight distribution is in the center of the flywheel because it would decrease the rotational inertia. I havent seen many dyno charts with just a lightweight flywheel addition if you know where I could find one please feel free the reason I'm asking is because I'm looking into buying one. thanks

 

[Old Mitsu Tech]

You are using less horsepower by turning less rotational mass. This in turn can be turned into a faster revving engine. You are going to sacrifice some lower end due to light mass but I don't think you will be bothered a lot by it.

Which is pretty much what toecutter said.

Good Luck

 

[big_eskimo]

You are using less horsepower by turning less rotational mass. This in turn can be turned into a faster revving engine. You are going to sacrifice some lower end due to light mass but I don't think you will be bothered a lot by it.

Which is pretty much what toecutter said.

Good Luck

I'm not trying to disaggree with you but how does a lighter flywheel equate to losing low end power? Is it because the turbo will spool later because there's less load on the engine? If this is the case it seems like it would be hardly noticeable if at all. Please let me know why this happens.
Thx,
R.J.

 

[jking29]

I'm not trying to disaggree with you but how does a lighter flywheel equate to losing low end power? Is it because the turbo will spool later because there's less load on the engine? If this is the case it seems like it would be hardly noticeable if at all. Please let me know why this happens.
Thx,
R.J.

It is because the heavy flywheel has a higher rotational mass which helps the motor hold revs better. With a lightweight flywheel, your motor will bog a little bit at lower revs but will rev faster because it no longer has to accelerate the extra weight of the heavy flywheel. It has nothing to do with the turbo spooling.

 

[big_eskimo]

It is because the heavy flywheel has a higher rotational mass which helps the motor hold revs better. With a lightweight flywheel, your motor will bog a little bit at lower revs but will rev faster because it no longer has to accelerate the extra weight of the heavy flywheel. It has nothing to do with the turbo spooling.

I see, so simply because the motor gains and loses rev's quicker because of less rotational mass, it loses some bottom end? Say you shift from first to second you'll lose more rev's than with a unlightened unit? Do I have this right?

 

[jking29]

That is absolutely correct. Its like having 2 tires that are spinning, a car tire and a 10 speed tire. It is easy to make the 10 speed tire spin faster, but the car tire will continue spinning even when some drag is put on it. The 10 speed tire will stop spinning completely with just a very slight drag on it.

 

[GILZTSIAWD]

I am from the world of automatics so I do not know the answer to this question, and I couldn't seem to find the answer. I need to know which aftermarket lightweight flywheel I can use with the stage 0 or oem spec exedy clutch? I have a guy that I am putting a new engine in for and he wants the lightweight flywheel put in also, but we only had the oem spec exedy clutch. I know that with an act clutch I have read that you have to have your stock flywheel stepped, so I figured that the x-act flywheel would come stepped already for that clutch? Which flywheels would work without any machine work with the stock spec clutch? I know it seems pointless to do a lightweight flywheel with a oem spec clutch, but the customer is always right Thanks for any help guys!

 

[DGajre777]

Well according to RRE 0.608" is stock step on a flywheel. 0.608" to 0.610" is ideal for DSM performance clutches, and their flywheels come stepped to .609" to .610" always.

They have Lightened Flywheels for $135 (with core exchange).

http://www.roadraceengineering.com/ecldrivetrain.htm
http://www.roadraceengineering.com/clutchandflywheeltech.htm

 

[GILZTSIAWD]

Thanks a lot man. I had read someone saying they had to get their flywheel stepped to a certain number and I was thinking they meant it was different than stock. I just misunderstood, they meant they needed to get it stepped to that to make sure it was still in spec. Once again, thanks!

 

[DGajre777]

Glad to be of help!

 

[TFI-J]

hi guys ,i'm wondering if anyone know abut this flywheel ,does it help on hp wise.
please let me know!!
thank you!!!

 

[importboost]

I have an ACT Xact lighted flywheel. I don't remember if its a streetlite, but i love it. It will feel like it increases hp but it really doesn't. The point of an aftermarket, lighted flywheel is for faster revs and strength.

 

[supermariobros]

Acceleration felt a little quicker and smoother when i put my act flywheel

 

[kenamond]

It won't increase hp, but it'll make the car quicker. It's like taking weight off the car so that you accelerate more quickly, but it's rotational mass, so the engine can rev more quickly. It can also withstand higher torque than the stock clutch, so you can upgrade without the clutch slipping.

 

[MyBeatGSX]

There is no real HP increase, you might see like a 1-2whp difference. Dave Colman hit on this briefly in SCC awhile back, if I remember correctly, removing 1lbs of flywheel (or engine rotating assembly) weight is roughly requivalent to removing 30lbs of body weight (in first gear. it gets less and less significant in higher gears).

Its main purpose is improved shifting. If you notice with the stock flywheel, you have to wait a bit between shifts for the revs to drop down. Its designed this way for young blonde girls that can't drive or shift fast. With the lightweight flywheel, the revs will drop very quickly when you put the clutch in, which helps make for smoother and faster shifts when you're shifting hard. The side effect is they also drop very fast during normal driving, so get used to shifting quickly, you can't take your sweet time between gear changes anymore.

It also slightly helps with throttle response and supposedly accleration, but I noticed only slightly better response and no difference in accleration except that I can now break the tires loose in 1st which is not a good thing.

Keep in mind the drivability issues. While no where near as bad as the Fidanzas, it still takes some getting used to to take off smoothly and when combined with a 2600 or stronger clutch, it can be a real PITA to drive.

 

[kenamond]

There is no real HP increase, you might see like a 1-2whp difference. Dave Colman hit on this briefly in SCC awhile back, if I remember correctly, removing 1lbs of flywheel (or engine rotating assembly) weight is roughly requivalent to removing 30lbs of body weight (in first gear. it gets less and less significant in higher gears).

Its main purpose is improved shifting. If you notice with the stock flywheel, you have to wait a bit between shifts for the revs to drop down. Its designed this way for young blonde girls that can't drive or shift fast. With the lightweight flywheel, the revs will drop very quickly when you put the clutch in, which helps make for smoother and faster shifts when you're shifting hard. The side effect is they also drop very fast during normal driving, so get used to shifting quickly, you can't take your sweet time between gear changes anymore.

It also slightly helps with throttle response and supposedly accleration, but I noticed only slightly better response and no difference in accleration except that I can now break the tires loose in 1st which is not a good thing.

Keep in mind the drivability issues. While no where near as bad as the Fidanzas, it still takes some getting used to to take off smoothly and when combined with a 2600 or stronger clutch, it can be a real PITA to drive.

Also, the car revs faster, so you can rev up to high rpm for a downshift faster - like when you're downshifting in a turn or in preparation for a turn.

 

[nightspeed87]

i bought a fidanza 8lbs flywheel, anyone try one of these... I havent put it in the car yet because it hasnt came in yet... What ive heard so far is that it revs a lot faster and helps to rev match better because the rpms fall quicker during shifts, and that the lightened flywheels are real jumpy under 25mph and takes practice to get used to correct?
How much do stock flywheels weigh, im sure there over 15 lbs...

 

[importboost]

i bought a fidanza 8lbs flywheel, anyone try one of these... I havent put it in the car yet because it hasnt came in yet... What ive heard so far is that it revs a lot faster and helps to rev match better because the rpms fall quicker during shifts, and that the lightened flywheels are real jumpy under 25mph and takes practice to get used to correct?
How much do stock flywheels weigh, im sure there over 15 lbs...

Taking off is a little rough sometimes. But you get used to it. I've heard a lot of stories about fidanzas blowing up.

 

[nightspeed87]

Taking off is a little rough sometimes. But you get used to it. I've heard a lot of stories about fidanzas blowing up.

ok thats wonderful.. Real comforting to know.... You are probably talking about high hp drag cars im supposing.

 

[MyBeatGSX]

i bought a fidanza 8lbs flywheel, anyone try one of these... I havent put it in the car yet because it hasnt came in yet... What ive heard so far is that it revs a lot faster and helps to rev match better because the rpms fall quicker during shifts, and that the lightened flywheels are real jumpy under 25mph and takes practice to get used to correct?
How much do stock flywheels weigh, im sure there over 15 lbs...

Yes the revs do fall very fast. Annoyingly fast in the cars I've driven with <10lb flywheels.

Yes it does take a bit of practice. I didn't want to drive my car for about a week after getting my XACT and 2600 put in.

No, there is no such thing as "jumpy" in a 3,500lb car with a 2.0L engine.

 

[importboost]

ok thats wonderful.. Real comforting to know.... You are probably talking about high hp drag cars im supposing.

No I'm really not. A friend of mine had one in his 92 fwd turbo talon. His exploded inside his transmission with not a whole lot of power goin through it. He had some good mods but nothing crazy. I'd say <350hp.

 

[talonproject]

IIRC the stock flywheel is 19 pounds
A more streetable flywheel is the act strretlite at 12 pds
beautiful combo when matched witha act 2100