Cruze/Sonic Custom Twin Disc Clutch Pics

[TravsSonic]

okay guys and girls.. here it is. This is the first twin disc assembly built for the Cruze/Sonic 1.4, this is for the M32 6-speed manual transmission. I pulled my assembly out of my then 2.5 month old cruze and shipped it off to california to Clutchmasters.com - High Performance Clutches and Flywheels They did a great job building me this setup. And I do know that they have a second one built for anyone that wants one. The price Jose told me was about $1600 which includes the shipping.

For some reference info the OEM utilizes a dual mass flywheel

pressure plate: 8.24 lbs
clutch: 2.38 lbs
flywheel: 23.96 lbs

total: 34.58 lbs

The new ClutchMasters unit is a twin disc stage 6, 725 series (7.25") assembly w/custom flywheel using two kevlar fiber discs. Wanted to stay away from the super noisy and touchy ceramic discs. So here is the new weights, and from the pics you will be able to see that he MOI has really been lowered and alot of weight as been pulled in very close so it should really spin up fast now. And as if 11 lbs wasn't light enough, Jose told me they could shave another 2 lbs off the flywheel if i wanted. I decided to not risk a temperamental 9 pound flywheel.. it was tempting.. but i said no.

pressure plate and discs: 8.72 lbs
flywheel: 11.09 lbs

total: 19.81 lbs

Weight Reduction of 42.7%

sorry, no pics of the OEM atm. Its still in transit from california. Will post some when it gets back to me.

 

[BNRacing]

If there is any interest in this, we are also Clutch Masters distributors, so we could probably get it cheaper than they quoted you once they start production.

 

[TravsSonic]

If there is any interest in this, we are also Clutch Masters distributors, so we could probably get it cheaper than they quoted you once they start production.

As a side note, when your OEM clutch poofs on you with the 1.4's. These guys can make everything from a stage 1 single disc OEM replacement type clutches to stage 8. They got all the dimensions from my assembly, so you won't have to send them anything. Just pick up the phone and give them a call or BNRacing a call or whatever.

 

[0h12Sonic]

yea i couldnt imagine spending so much on a clutch...
how much do you think a stage 2 would run?? Im not lookn to race such a heavy car with a baby engine...
I bet with that lightweight flywheel rpm's are much more zippy...get a vid when you get it in!!

 

[blkside]

I hope its better than the 1600.00 I saw around here. That would be ridiculous. My Evo entire setup installed is hundreds less than that so hopefully it gets to the point where its reasonable.

 

[BNRacing]

The $1600 is for a twin disc. I'm sure a stage 1 will be around $500. The Cobalt SS stage clutches run around 500-600 and a twin disc for those cars is $1500-$1700

 

[TravsSonic]

yeah, twins are expensive compared to singles. And BNR is right, singles should be in the $500 range.

 

[TravsSonic]

I bet with that lightweight flywheel rpm's are much more zippy...get a vid when you get it in!!

will do. I've got to put 500 stop and go miles on it, then i'll go make a few passes.

okay, i've got a clutch to put in.. ya'll have a good day

 

[blkside]

Well thats good to know.. I dont plan on doing any power mods but should I, I want the costs to be reasonable for upgrades...

 

[TravsSonic]

First test drive with twin disc

Well i've gotten to take my first test drive with the new clutch and here is my feedback for it.

As a whole, its exactly what I expected.. there is basically no lag as the engine spins up between idle and where the turbo starts to spool.

It is alot more peppy, and i keep finding myself turning 4k+ rpm without even noticing it. Which is good and bad, good for fun, bad in the sense that 4k in 4th is like 80mph but it gets there so effortlessly that i'm gonna really have to retrain my brain.

I haven't knoticed any of the tattle tell gear grind all the M32's give in the 5-5.5k range on the 1-2 shifts with the 1.4. Its a EXTREMELY common complaint, which just confirms to me that the OEM pressure plate is a POS. If you do any mods to the 1.4, make a new clutch/pressure plate from clutchmasters be one of the first mods. Or go crazy and and order up a stage 6, 7.25" like mine. I'm not sure everyone would be happy with this clutch though. For a couple reasons

It talks.. ALOT.. i knew before i had it built that it would "chatter", thats the best word for it. I'm guessing that the harmonics on the engine between strokes and the tiny amount of slop between the splines on the input shaft and the unsprung discs makes it talk while not under power and moving down the road. If the discs were sprung.. i seriously doubt you could ever hear it. And while in the car it is almost completely quite. But step outside the car, it sounds like a little chatter box. One person said it sounded like a diesel.. haha. Its a little noisy.. but its unique and it got rid of that damn OEM clutch assembly, so i'm extremely happy with it.

two other little issues. I am going to have to build a clutch stop for it, it engages and disengages over about 1/4" which is exactly what the tech support said it would be. And i still have to much pedal, so tomorrow i'll be building a clutch stop.

The last issue is the clutch safety starter switch is going to either have to be relocated to be a button i push somewhere or i'll just have to modify the sensor so it thinks i've got the clutch down all the time. The switch is to far down in the throw and runs the risk of over extending the PP.

 

[Sonic]

You will have to watch your fuel economy. Spinning to 4k+ rpm all the time won't be good for the mpg.

 

[klystron]

You will have to watch your fuel economy. Spinning to 4k+ rpm all the time won't be good for the mpg.

The lighter flywheel should improve MPG by having less weight on a rotational mass.

 

[Sonic]

Initially, yes, but the constant rpm elevation would offset that. But the same could be said of anyone with a "lead foot".

 

[TravsSonic]

i got tickled at one of my buddies i ride motorcycles with, he walked out to see my car. I had it sitting there idling.. he was comparing its idling noise to some bikes with multi disc dry clutch systems and how they sounded very similar. Then he was like.. "its noisy, but i like it, sounds like its got a rod knocking. Perfect sleeper" OMG!! hahahaha

I was getting some pretty good instantaneous mpg at 70 in 6th on cruise control, it was bopping around between 45-65 mpg. I can't wait to take it on a road trip to see what kind of mileage it can get on the freeway driving for several hours. In town though.. it drops off fast. I reset my dash after i got it running yesterday, and right now its showing about 31 mpg as an average. About 5 less than i normally run, but i really do blame all that on a heavy foot and just seeing how it felt. I should know more in a few weeks

 

[wingman]

Thats sweet, but not for me. A builder once told me that the stock heavier flywheel was more reliable because of its mass and the inertia of a moving object staying in that state. I dont remember the exact explanation and this was for the motor I was building for my 67 bug. But I bet your sonic revs hella faster. As for the free play in your clutch, am I understanding this right, you have a little over 1/4" of free play before clutch engages. Or is it a total of about 1/4" of friction zone total?

 

[TravsSonic]

There is about 1/4 to 1/2" worth of pedal that you have to feather the engagement. Its not much, and the kevlar is sticky and bites like mad. so you really have to be on your toes when you creep around.

I've had a few people try to drive it, the normal routine is they kill it 3-10 times and either give up or get pissed and dump the clutch to get it to move. Heck i still occasionally kill it.. did it just the other day, which resulted in the roar of laughter and ample amounts of heckling from my passengers.. it was quite entertaining.

I have the Cruze, but it has the same engine/transmission as the sonic, and yes it is a very rev happy little monster now. All the lag before the turbo spools is gone, the tach sweeps very naturally now. No more pulling out of driveways and cussing because it fell on its face while waiting for the turbo to spool. It has made driving around much more enjoyable.. but as posted before. 4k rpm shifts is the norm now, it spins up pretty quick, so my mileage suffers in town. I'm still averaging 37 mpg over all, so I won't complain.

Issues i currently have.. for starters, don't expect the front end to get any bite. Even with T/C on, and with a rolling start, smashing the gas will break the wheel loose and spin it. LSD is a must and is next on my list. They run about $1050 right now.

I also wish i would have taken Jose up on the offer to shave another 2 lbs off the flywheel. 11lbs is okay but I think 9lbs would have been better... or maybe i've just gotten use to the 11 lbs.

I also wish i had went with one sprung and one unsprung disc. Currently i'm running two unsprung discs. There is a small degree of slop that has to be designed into the splines on the disc so that it slides freely onto the input shaft of the transmission. The noise produced by that TINY bit of slop is normally absorbed by the springs in a sprung clutch disc. Since mine is solid on both, all that noise transmits back to me.. it can be quite noisy at times. I will probably have them make me up a sprung disc this spring and i'll pull the transmission again and redo it. I'd really like to hear the difference in the harmonics.

anyway.. if anyone has any questions about it, just ask.

 

[Danny5]

Actually, lightened flywheels tend to decrease your MPGs because off throttle coasting isn't as efficient.

Just sayin!

 

[sonic007]

Did you see any performance gains from the weight loss?

 

[TravsSonic]

Did you see any performance gains from the weight loss?

considerable.. but its not something i can put a stopwatch to due to traction limitations of being both pegleg and eco's hard ass tires. Right now i'm saving for a LSD and different shoes so i can see what its really capable of.

currently this is how it works with this set up, WITH traction control on, when you roll away from a light at an idle then mash the accelerator it will break the tire loose as soon as the turbo comes on...everytime. Heres some video of it chirping 3rd at the top end of a drag strip, you won't catch the OEM setup doing that.
2011 Eco Cruze barking 3rd gear? WTF?!?! - YouTube

as a side note to this video, i was playing with launch rpms to find the limitations of the tires. 2.13 @ 60' is the best i squeaked out on those hard ass PoS OEM tires. The run in the video was like a 2.19 while spinning all the way through 1st.

there is a heavy price to pay for a setup like this.. its touchy and its noisy. After 10k miles, i still routinely kill my car in town driving. And the harmonics of the engine make the slop between the input shaft and the splines on the unsprung discs very very noisy. You can quite some of it by upping the idle to 1.1k rpm but it doesn't get rid of it all.

 

[JamesMay]

considerable.. but its not something i can put a stopwatch to due to traction limitations of being both pegleg and eco's hard ass tires. Right now i'm saving for a LSD and different shoes so i can see what its really capable of.

currently this is how it works with this set up, WITH traction control on, when you roll away from a light at an idle then mash the accelerator it will break the tire loose as soon as the turbo comes on...everytime. Heres some video of it chirping 3rd at the top end of a drag strip, you won't catch the OEM setup doing that.
2011 Eco Cruze barking 3rd gear? WTF?!?! - YouTube

as a side note to this video, i was playing with launch rpms to find the limitations of the tires. 2.13 @ 60' is the best i squeaked out on those hard ass PoS OEM tires. The run in the video was like a 2.19 while spinning all the way through 1st.

there is a heavy price to pay for a setup like this.. its touchy and its noisy. After 10k miles, i still routinely kill my car in town driving. And the harmonics of the engine make the slop between the input shaft and the splines on the unsprung discs very very noisy. You can quite some of it by upping the idle to 1.1k rpm but it doesn't get rid of it all.

I know this thread is old, but is that drag strip in Centerville AK ?