Was browsing around and found this interesting article where they did a flywheel+clutch on an M3 with before/after dynos. This may be a repost and it's probably an old article but anyway:

http://www.europeancarweb.com/projec...109ec_projbmw/

He concludes by listing all the pros and cons of going with a lightweight flywheel, and that to him the benefits outweigh the slight loss in torque down low. Granted it's an M3 and not a VQ but I'm thinking te results should be very similar.

 

interesting article. thanx. doesn't really make me overly enthusiastic about an a/m setup, tho, as there are not really any "big" gains, but every little bit helps in the case of the z, i guess.

 

Ya, I have to admit that I wasn't as excited about this mod after reading that either.

It seems the only real benefits are on the road race track and maybe from a roll on the street. Most of the changes in power/torque are in 1st gear which seem to hurt things like 1/4 times and stoplight encounters. I'm still undecided.

 

Hum...interesting...as the matter of fact i am also in the market of getting my clutch/flywheel upgraded.
Hey copba1t, have you read and other reviews on other car of any aftermarket clutch/flywheel setup?

 

That M3 article is the best one I've come across, but I've also read a couple others blurbs that only seem to focus on the positive and not even mention the losses down low. I was impressed with the writer on the BMW project, he seemed very objective and layed it out pretty straight, and did not pretend to be an expert but rather just another enthusiast.

Overall I think I'm leaning towards going with a flywheel and beefier clutch because:

1) Eventually I'll do things like road racing and I'll need the clutch anyway if I do the APS single turbo =)

2) I'm not really much of a drag *****, it's fun but just once in a while

3) I play on the street more from a roll than at lights, and of course this mod seems great for highway runs too

 

going with the tilton is even more of a dramatic change than in the article

you can tell a huge difference in 1st, 2nd, and 3rd. Maybe slightly in 4th. 5th and 6th feel same as stock

I think if you were to drag race two equal cars, but one had a light flywheel, that one would win. It might not be the first off the line, but if you're pushing the car all the way to redline, the modded flywheel will help here because every time you shift, you're going to be in the upper rpm range.

So at launch, the stock car will have the advantage over that short amount of time it takes to climb 2/3 through 1st gear

the car with the clutch/flywheel will have the advantage at the last 1/3 of 1st gear, then the short duration that you're in 2nd, 3rd and maybe 4th. By the time you get to 5th, it won't matter anymore.

There's something to be said for ease of drivability though with keeping the clutch/flywheel stock

 

Hmm, I wonder if the Tilton would lose even more torque down low then?

There are all kind of variables at work, which is why it's seemingly hard to get a grasp of it all, at least for me. For instance, one could logically think that the additional HP in the very upper part of 1st would gain back any losses down low, just as the editor said, and then the increased responsiveness of the new flywheel should help even more.

But alternatively you could also say that it's torque that really matters when you are getting off the line, not HP.

All I know is most of the slips I have come across with before/after flywheel mods show that the 60' and 1/8 times were definitely slower with the lightweight flywheels. The ETs were also slower in almost every case. Some people claim it's traction, or some other reason, but I think that is just because it's harder to make up ground once you get moving because acceleration drops as your speed increases.

 

If this is true, I think it would make the 1/4 mile times even worse for the Tilton because you are giving even more of an edge to the stock flywheel in the lower MPH where the acceleration rate is typically higher.

Yes the Tilton would have the edge in higher MPH but at that point the acceleration rate has dropped considerably so the gains may not be as significant as they would appear (slightly higher trap speed).

I'm just thinking out loud here, anyone feel free to chime in with their thoughts or a better explanation.

 

Found another article (also may be old) that is actually about a project Z where they drop in a flywheel and then compare track times. They end up with the same ET but higher trap. Unfortunately they also make some other changes including rims/tires and LSD, so the results aren't as conclusive. Here is where he summarized the flywheel mod:

I think his comment about less grip with the oversized tires (265/35x18 Toyo on Nismos) is definitely a load of crap though. Something was lost at the launch allright, it's called torque dude!

The article has some other good info on modding the Z including a very good breakdown and analysis of the stock VLSD:

http://www.sportcompactcarweb.com/pr...8scc_proj350z/

 

Cobalt,
ya, that's an old article and a good one i forgot about. how can they attribute the loss off the line to fatter tires??? I don't think so.
i guess its about where you want the power most, and where you're willing to give it up. of course, i want more power at both ends, so i'm really undecided about what to do re clutch and flywheel at this point.
off topic, have you posted your custom reducer solution here on this site? if you have, i haven't seen it, and i think lots of people would benefit from it, if it has worked well for you.

 

I think I posted a link to it in the "$95 resonated test pipes..." thread in response to someone bringing up the pipe diamter mismatch issue, but I'll go ahead and toss up a new post about it as well, thanks =)

 

I wish I had the dynos from the same place...

but...

This graph shows my car with only NISMO Exhaust... then adding RT High Flow Cats...

(Make note of the TQ Curves Scale to what the HP Curves scale is...)



This next graph is a big gap...

I removed the cats and put my stock cats back on... Added Tilton Flywheel and clutch, UR Crank Pulley, JWT Pop Charger, and DC Ceramic Headers...

I lost some low end TQ since I was running lean up to about 4.2k... I havent done any tuning yet..

 

so you gained about 7hp and 8lb tq with your first batch of mods, and added another 10hp and lost a little tq with your second.

 

i also only addted the high flow cats in the first graph...

It goes...

241.4RWHP / 231.3TQ
248.0RWHP / 239.3TQ
258.2RWHP / 237.4TQ

Well see what the new lower plenum does

 

like i said before when you told me why you went back to stock cats, conversation is highly overrated.

 

JWT flywheel review

http://www.sportcompactcarweb.com/pr...8scc_proj350z/

 

wrong link =]

http://www.nissanperformancemag.com/october03/350z_fly/

 

It's just too bad that there is really no way to figure out a measured amount of the gains to expect with this mod, because the increased responsiveness does not show on the dyno. Maybe you could analyze some drag slips and only look at the (60' - trap) data or something...

Hmm, if I actually remembered any physics from school, I would be temped to create some sort of estimator tool, where you import your vehicle data (dyno, 1/4 mile, un/sprung weights, gear ratios) then it would allow you to change different variables like vehicle weight, wheel/flywheel/pulley weights or sizes and then it would recalculate the performance data and tell you what would change and by how much. That would be cool

 

Has anyone seen a tool that does anything like this? I'm sure there must be something out there that does something similar...