What are you AutoXers using for a clutch?
I run an Exedy Twin SD in SM. It gives up some clamping force to the HD models but has a true stock pedal feel.
In our region, we typcially have about 5-6 runs. With the way the run groups are split up, we get all of our runs done in about an hour. So figure on 5-6 hard launches within an hour and the Twin SD is still consistent without dropping off (my stocker could only handle about 2-3 launches in an hour before losing some grab).
In our region, we typcially have about 5-6 runs. With the way the run groups are split up, we get all of our runs done in about an hour. So figure on 5-6 hard launches within an hour and the Twin SD is still consistent without dropping off (my stocker could only handle about 2-3 launches in an hour before losing some grab).
I run an Exedy Twin SD in SM. It gives up some clamping force to the HD models but has a true stock pedal feel.
In our region, we typcially have about 5-6 runs. With the way the run groups are split up, we get all of our runs done in about an hour. So figure on 5-6 hard launches within an hour and the Twin SD is still consistent without dropping off (my stocker could only handle about 2-3 launches in an hour before losing some grab).
In our region, we typcially have about 5-6 runs. With the way the run groups are split up, we get all of our runs done in about an hour. So figure on 5-6 hard launches within an hour and the Twin SD is still consistent without dropping off (my stocker could only handle about 2-3 launches in an hour before losing some grab).
Engagement:
The engagement window is pretty good but still kinda "on/off" at engagements under 1.5K rpms compared to a stocker due to less rotational mass to lessen the stalling affect.
The pedal pressure feel, like I said, was the same...if not just a *tad* bit softer than stock. I daily drive this thing in stop&go traffic and after feeling a friend's HD...I went with the SD. The HD ain't that bad, but it was noticeably stiffer than stock (no go for driving stop&go).
Noise:
Sometimes it makes a "Chair being drug across a wooden floor" noise every once in awhile (mostly on the first couple of engagements in the morning on cold days). I've been in Afghanistan since Jan. so I can't really remember if there were any other annoying noises like chattering, etc. I've had a car with an 8.5lb flywheel before (BMW) so I am probably numb to the noises anyways.
There was a little bit of getting used to the twin disc as far the jerkiness. That goes back to the fact it is a lighter, grabbier system. So yes..plan on "bucking" a little bit your first week with it.
Now..I don't know about 400whp/400wtq. It might hold the power, but I have no idea for how long and for how much abuse. I'm not putting down nearly that much....less than 300whp/wtq. I don't know what the torque rating is for the SD's.
That's the pro and con for going for the SD over the HD pressure plate. Softer pedal feel but less clamping force. Both clutch kits use the same discs (IIRC) so it just comes down to if you are going to overload the SD or not. With your numbers...I would probably go with an HD. I don't think an HD will make any more or less sounds than an SD.
Hope this helps you.
The engagement window is pretty good but still kinda "on/off" at engagements under 1.5K rpms compared to a stocker due to less rotational mass to lessen the stalling affect.
The pedal pressure feel, like I said, was the same...if not just a *tad* bit softer than stock. I daily drive this thing in stop&go traffic and after feeling a friend's HD...I went with the SD. The HD ain't that bad, but it was noticeably stiffer than stock (no go for driving stop&go).
Noise:
Sometimes it makes a "Chair being drug across a wooden floor" noise every once in awhile (mostly on the first couple of engagements in the morning on cold days). I've been in Afghanistan since Jan. so I can't really remember if there were any other annoying noises like chattering, etc. I've had a car with an 8.5lb flywheel before (BMW) so I am probably numb to the noises anyways.
There was a little bit of getting used to the twin disc as far the jerkiness. That goes back to the fact it is a lighter, grabbier system. So yes..plan on "bucking" a little bit your first week with it.
Now..I don't know about 400whp/400wtq. It might hold the power, but I have no idea for how long and for how much abuse. I'm not putting down nearly that much....less than 300whp/wtq. I don't know what the torque rating is for the SD's.
That's the pro and con for going for the SD over the HD pressure plate. Softer pedal feel but less clamping force. Both clutch kits use the same discs (IIRC) so it just comes down to if you are going to overload the SD or not. With your numbers...I would probably go with an HD. I don't think an HD will make any more or less sounds than an SD.
Hope this helps you.
What's up Kiley? I use the Twin Disk HD and there's no issues for me running the SM class. As far as driveability, I don't have any issues either. The engagement can be tricky & does take some getting used to. But like Kiley said, run after run there's no problems whatsoever.
kiley_sean's thread should be a sticky for the perfect description of an exedy twin 
I'm running the same clutch and that description matches mine to a "T"
"Sometimes it makes a "Chair being drug across a wooden floor" noise every once in awhile..."
That really is what it sounds like!
The exedy twin has worked great for me, and I'd rebuild it when the time comes.
I'd also look into the Spec line of twin disc clutches.
I'm running the same clutch and that description matches mine to a "T"
"Sometimes it makes a "Chair being drug across a wooden floor" noise every once in awhile..."
That really is what it sounds like!The exedy twin has worked great for me, and I'd rebuild it when the time comes.
I'd also look into the Spec line of twin disc clutches.
What's up Lecon. I didn't know you had an HD. I'll be back in July to join you guys back in the Autox's. I heard that SM is still where it's at this year.
That's what I plan on doing. I've been very pleased with it so far.
That's what I plan on doing. I've been very pleased with it so far.
Engagement:
The engagement window is pretty good but still kinda "on/off" at engagements under 1.5K rpms compared to a stocker due to less rotational mass to lessen the stalling affect.
The pedal pressure feel, like I said, was the same...if not just a *tad* bit softer than stock. I daily drive this thing in stop&go traffic and after feeling a friend's HD...I went with the SD. The HD ain't that bad, but it was noticeably stiffer than stock (no go for driving stop&go).
Noise:
Sometimes it makes a "Chair being drug across a wooden floor" noise every once in awhile (mostly on the first couple of engagements in the morning on cold days). I've been in Afghanistan since Jan. so I can't really remember if there were any other annoying noises like chattering, etc. I've had a car with an 8.5lb flywheel before (BMW) so I am probably numb to the noises anyways.
There was a little bit of getting used to the twin disc as far the jerkiness. That goes back to the fact it is a lighter, grabbier system. So yes..plan on "bucking" a little bit your first week with it.
Now..I don't know about 400whp/400wtq. It might hold the power, but I have no idea for how long and for how much abuse. I'm not putting down nearly that much....less than 300whp/wtq. I don't know what the torque rating is for the SD's.
That's the pro and con for going for the SD over the HD pressure plate. Softer pedal feel but less clamping force. Both clutch kits use the same discs (IIRC) so it just comes down to if you are going to overload the SD or not. With your numbers...I would probably go with an HD. I don't think an HD will make any more or less sounds than an SD.
Hope this helps you.
The engagement window is pretty good but still kinda "on/off" at engagements under 1.5K rpms compared to a stocker due to less rotational mass to lessen the stalling affect.
The pedal pressure feel, like I said, was the same...if not just a *tad* bit softer than stock. I daily drive this thing in stop&go traffic and after feeling a friend's HD...I went with the SD. The HD ain't that bad, but it was noticeably stiffer than stock (no go for driving stop&go).
Noise:
Sometimes it makes a "Chair being drug across a wooden floor" noise every once in awhile (mostly on the first couple of engagements in the morning on cold days). I've been in Afghanistan since Jan. so I can't really remember if there were any other annoying noises like chattering, etc. I've had a car with an 8.5lb flywheel before (BMW) so I am probably numb to the noises anyways.
There was a little bit of getting used to the twin disc as far the jerkiness. That goes back to the fact it is a lighter, grabbier system. So yes..plan on "bucking" a little bit your first week with it.
Now..I don't know about 400whp/400wtq. It might hold the power, but I have no idea for how long and for how much abuse. I'm not putting down nearly that much....less than 300whp/wtq. I don't know what the torque rating is for the SD's.
That's the pro and con for going for the SD over the HD pressure plate. Softer pedal feel but less clamping force. Both clutch kits use the same discs (IIRC) so it just comes down to if you are going to overload the SD or not. With your numbers...I would probably go with an HD. I don't think an HD will make any more or less sounds than an SD.
Hope this helps you.