Launch limit for aluminum flywheel

[AWD-Tony]

What do you guys with aluminum flywheels launch at? This is my first aluminum flywheel and out of 4 run I bogged the car 3 times. My launch limit is set to 5k.

Thanks
Tony

 

[ThunderChild]

With less stored energy you're going to have to up the launch rpm probably. I launched my car @ 5500, granted stock flywheel and only a 14b, but I still suspect you will need more rpm to maintain power through the launch given less rotating mass to keep inertia up.

 

[AWD-Tony]

Thanks, Henry! That makes sense. I completely forgot about having an aluminum flywheel yesterday at the strip and didn’t want to raise the LL since I’ve always launched it at 5k in the past. I’ll have to practice before I head back.

 

[1990TSIAWDTALON]

I ran a Streetlite and you will probably be up to 55-5700 like Henry said. No energy in the light flywheel. Rev the piss outta it T!

 

[AWD-Tony]

I will. My buddy filming kept telling me to up the launch limit but being the stubborn @ss that I am, I kept saying I didn’t want to break something and I’ve always launch it at 5k. I’m an idiot

 

[DSMPT]

I was using an aluminum flywheel for many years and I was launching at around 6500 or maybe a bit higher but with slipping the disc. Only what I broke at launch at that moment was the 3 bolt rear axle.

 

[AWD-Tony]

I was using an aluminum flywheel for many years and I was launching at around 6500 or maybe a bit higher but with slipping the disc. Only what I broke at launch at that moment was the 3 bolt rear axle.

6500 . Dang Hiroshi!!! Not bad if it’s just the rear axles. I’ll take axles any day over other driveline parts.

I’m too scared to break something even slipping it of course. I’ll make some test hits and hopefully 5500 works for me.

 

[jakk220]

6500 . Dang Hiroshi!!! Not bad if it’s just the rear axles. I’ll take axles any day over other driveline parts.

I’m too scared to break something even slipping it of course. I’ll make some test hits and hopefully 5500 works for me.

I was launching at like 6k with my Fidanza flywheel on my HX40. I used to launch it at 5k with my 16g or my FP green and it wasn't too bad. Mostly because I was able to build boost. Once I put the .70ar turbine housing on my HX40 I lost a lot of that boost off the line. I was only getting maybe 1psi.

I opted to run a mild anti-lag instead and keep the launch limit at about 5600. I just switched to a street lite instead of the Fidanza as well so I can run a more aggressive clutch material. The Fidanza was also a bit too light for me. Once I get the transmission back together this year I am going to try to up the limit to 6k and see if I can run a little more timing on the anti-lag to make it even more mild.

 

[clutchtamer]

6500 . Dang Hiroshi!!! Not bad if it’s just the rear axles. I’ll take axles any day over other driveline parts.

I’m too scared to break something even slipping it of course. I’ll make some test hits and hopefully 5500 works for me.

Install one of my clutch hit controllers and you can leave from 7500+ without breaking parts. Bumping launch from 5500 to 7800 will more than double the amount of "inertia boost" available to get the car moving, without suffering the negative effects of increased flywheel weight.

Here's a graph showing a NA 7200 dead hook launch using one of my clutch hit controllers. Notice the higher "G" trace until about .85sec in, that's due to the "inertia boost" that you get while the clutch is drawing the engine down. That inertia boost is stored energy exiting the rotating assy, in this case it helped get the car launched without drawing engine rpm below 5000. Also notice from .85sec to the shift point the "G" data is significantly lower, that's the car's acceleration rate without any help from inertia boost.

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If we installed a heavier flywheel and lowered rpm to achieve the exact same amount of stored launch energy, the engine would accelerate slower from .85sec to the shift point due to the heavier flywheel.

If this were a nitrous car, we would delay the nitrous just enough so that it came in on the heels of the inertia boost. Done right, the transition from inertia boost to nitrous boost is almost seamless. For a turbo car inertia boost can be a substitute for lack of boost while the added rpm also raises boost on the line, which reduces the need for anti-lag.

You need a clutch hit controller to make it work, it's what allows you to adjust the rate of inertia discharge to a level that's productive.

Grant

 

[AWD-Tony]

Thanks guys!! Not launching the car anytime soon . Blew the hg yesterday so think it’s time to build the bottom end and go mls hg with L19s. Fingers crossed it’s just the hg. No funky noise when turning the engine over. Taking the head off this week.