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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Awesome that you finally got all this together! A massive amount of effort (time and money) and Im sure you will be paid back handsomely
Couple of comments.....the shifting improvements is at a minimum 50% due to the clutch swap (conservative figure). The completely different clutch design you just installed is directly responsible for how light it shifts and how smoothly it shifts. Its primarily due to the lightweight carbon/aluminum disc which weigh a pound and half each (amazing actually) versus a conventional twin disc that weigh 8-10 lbs each. Your syncho's in the trans have much less mass to slow down and speed match each gear....in fact its one of the major selling points of this clutch design and I felt I needed to set the record straight on that. That light shift effort is all about the reduced inertia of the RPS discs....your trans simply doesnt have to work as hard to shift gears. Im sure a few guys running my clutch would agree and they just swapped clutches....no trans upgrades experiencing the same thing. The new trans is certainly the icing on the cake though with fresh grabbing synchro's compounding the gains from the clutch upgrade.
Last and most importantly....how are you liking the Josh 3.5 muffler upgrade!? I know alot of time went into that fabrication.....is it really quiet and drone free closed and how does it sound at WOT?
Congrats once again on getting the car back on the road
Cheers,
Tony
I'll second Tony on this. I have the to a with the aluminum flywheel which is even lighter than Tony's and just the clutch swap alone changed the transmission. I also went to red line fluid at the same time but shifting just and town and at wot became much lighter with the rod over stock. People really underestimate how much of a penalty they suffer using a heavy clutch
If this proves to be "THE" setup...are you still contemplating an attempt to fabricate an airbox lid for the LG? Might be fun...
Yes. I'll return to making that intake fully functional again. Right now I'm thinking it will be fabricated out of aluminum though. I know nothing about carbon fiber so modifying the LG upper would be done by a pro. And aluminum is probably less costly to fabricate than CF, guessing.
Yes. I'll return to making that intake fully functional again. Right now I'm thinking it will be fabricated out of aluminum though. I know nothing about carbon fiber so modifying the LG upper would be done by a pro. And aluminum is probably less costly to fabricate than CF, guessing.
Aluminum would definitely be the easier route...fab it up and maybe get it ceramic coated. Would look cool for sure...
Awesome that you finally got all this together! A massive amount of effort (time and money) and Im sure you will be paid back handsomely
Couple of comments.....the shifting improvements is at a minimum 50% due to the clutch swap (conservative figure). The completely different clutch design you just installed is directly responsible for how light it shifts and how smoothly it shifts. Its primarily due to the lightweight carbon/aluminum disc which weigh a pound and half each (amazing actually) versus a conventional twin disc that weigh 8-10 lbs each. Your syncho's in the trans have much less mass to slow down and speed match each gear....in fact its one of the major selling points of this clutch design and I felt I needed to set the record straight on that. That light shift effort is all about the reduced inertia of the RPS discs....your trans simply doesnt have to work as hard to shift gears. Im sure a few guys running my clutch would agree and they just swapped clutches....no trans upgrades experiencing the same thing. The new trans is certainly the icing on the cake though with fresh grabbing synchro's compounding the gains from the clutch upgrade.
Last and most importantly....how are you liking the Josh 3.5 muffler upgrade!? I know alot of time went into that fabrication.....is it really quiet and drone free closed and how does it sound at WOT?
Congrats once again on getting the car back on the road
Cheers,
Tony
It would be wrong to speculate too precisely on where to credit the shifting improvement. The RPM Transmissions internals are all micro-polished, cryo treated, and their carbon synchros are just amazing. The weight difference between the BC2 clutch discs and LT1-S clutch discs was not significant. Obviously the real weight difference in the clutch assembly is the lighter pressure plate. I can say with confidence that the carbon discs have a cleaner disengagement than the marceled discs of the LT1-S, with the carbon discs fully releasing the driveline from the engine to let the synchros slow down the selected gear. Different trans, different clutch fluid, different clutch. I tried a delrin **** but put my C6 alcantara **** back on. The throws are lighter and smoother even with the engine off, which is purely the trans as we know. Regardless of what is doing what, it's a big improvement. The RPS unit has a bit of chatter when slipped, nothing to merit a complaint, just an observation. Other than that it's a very driveable clutch, even with the big cam. The new gear ratios are helping out in that department too.
The exhaust turned out really well. Overall I'm extremely pleased. I ran it to the top of 3rd gear a couple hours ago and it would have woke the dead. The exhaust is doing everything I hoped it would do. It's not hitting anywhere and just works. Center console temps aren't bad after a long drive either.
Yes. I'll return to making that intake fully functional again. Right now I'm thinking it will be fabricated out of aluminum though. I know nothing about carbon fiber so modifying the LG upper would be done by a pro. And aluminum is probably less costly to fabricate than CF, guessing.
Let me know if you need to ditch the LG unit....I'd be interested in it
The clutch pedal was staying on the floor during high rpm shifting. I removed the clutch pedal spring....much better now. Operates well and the pedal feeling is far more predictable.
The clutch pedal was staying on the floor during high rpm shifting. I removed the clutch pedal spring....much better now. Operates well and the pedal feeling is far more predictable.
I'll try to get the car on the dyno this week.
nice so your on the stock master? I’m running the tick which had a 7/8th bore way to short then tried a 5/8th bore way to long now back to stock size 3/4 feels much better. Do u have hanging idle now with clutch?
The clutch pedal was staying on the floor during high rpm shifting. I removed the clutch pedal spring....much better now. Operates well and the pedal feeling is far more predictable.
I'll try to get the car on the dyno this week.
Josh,
Is this advised w the install of the mamo bc2?
My car goes in next week for all the mamo mods in one shot. Looking for any pointers to avoid doing things twice.
Is this advised w the install of the mamo bc2?
My car goes in next week for all the mamo mods in one shot. Looking for any pointers to avoid doing things twice.
If you want my advice, I say do what works best for you. If it gets put together and you feel like the pedal wants to stay on the floor at high rpm, try pulling out the C6 clutch pedal return spring, it will return better and feel more predictable. But I would start off with the spring installed, test drive the car, then if the pedal stays on the floor, remove the spring as it's much easier to remove than to install.
Interesting that the "return spring" would keep the pedal to the floor...seems counter-intuitive to me, but its not the first time I've herd this.
It's an over-center spring design. It wants to be halfway, and would be if the master cylinder is out of the car. So the clutch diaphragm has to fight against the over-center spring from halfway to the top of the pedal travel. And if the clutch diaphragm is soft at high revs, it's too much to over come, resulting in a pedal around halfway in its travel.
I finally made it to the dyno a few days ago for some real results with the new clutch.
Notice the spike in torque at 5100 rpm, as well as the unstable up and down wavyness of the curve.
We tried locking out the timing in the upper cells on the second run, just to isolate spark as a variable. Same overall shape as the first run. According to a few engine experts I trust, my results could be attributed to improper valve control. By all indications, the tune is clean, the logs are clean.
I pulled my valve covers just to inspect for any obvious indicators. I couldn't see anything out of adjustment. My cold lash is still .003". No broken outer springs that I could see.
In my opinion, this is valve float. My previous dyno results were smooth. The most recent dyno results (Jan 2018) with the G1pro manifold had a little wavyness in the upper rpms, we played with spark then, and it was still a bit wavy.
I'll be removing the heads to give them a proper inspection. Seeing the valve float results from Jayyyw's build it goes to show that valve float sometimes barely shows itself on a dyno graph. So I won't be taking any chances.
If it is the springs can you buy a pack of the super lightweight springs and pull them while on the car take them down to the machine shop to have the springs tested?
06-06-2018, 06:44 AM
