CLUTCH UPGRADE RESULTS, VERY INTERESTING

[Skip White]

I've installed the clutch upgrade in the SRT.

Nearly 20lbs. reduction of rotational weight.

The car feels great with this. The flywheel, pressure plate, and disc were all lighter components. 6 puck ceramic, Spec light weight PP, Fidanza flwheel,

This is one of several clutch upgrades I've done on Vipers, and I can tell you, until you do it, you will be convinced that your clutch is not slipping, "it is". The positive feel of lunging you forward in every gear change is proof of that. It's second and third gear that the preheated oem unit slips most.

This setup is not without it's problems, I have severe clutch chatter, but getting much better with break in.

I have a very low to the floor disengagement point, and it's not totally disengaging, as the trans is very notchy. This could be caused by one of several different things. I'll figure it out. You can really appreciate if your clutch is fully disengaging about mid way if you drive one thats not. Could be something as simple as air in the hydro system.

If the chatter doesn't get better, I'll be changing out the disc, as it is a 6 puck ceramic, with a sprung hub, and these can vary in how they will turn out.

All in all, I'm very pleased at this point. I know I'll have to pull the tranny a couple more times to get it right. Cluth upgrade results can vary greatly from one system to another. The nature of the way the car drives is very different, not in a bad way, but does take some getting used to. The car just feels wild, with these light weight components, and the tremendous lunging effect of a clutch thats not slipping.

I've used Centerforce in the past, but they are very heavy in weight, and have other problems as well.

If any one wants to see pics of these components, e-mail me.

Skip White

ps,next project, 305/45/18 Nitto Drag Radials 28.2 inches tall, mounted on light weight HRE 546's,(they will be custom built for this size) then a set of 3.55's gears are coming, and last but not least, BTR system

 

[RavenFan_94]

Great path on the mods Skip. Thanks for the thorough write up on the clutch. Keep us posted with your progress.

 

[1TONY1]

I would say your stock clutch only slipped at engagement the way it is designed to do. Now you have chatter = no slip at engagement. After engagement the stock clutch will not be slipping on a mostly stock Viper (with a good clutch)I am still dealing with clutch/flywheel setups/changes on my gen2 and have seen your problems.

 

[Skip White]

Please share solutions. Anyone thats had set backs on this mod, let me and all out there know.

Tony, you have a very fast car from what I see. Let's here more on what you went through with clutch issues.

My worst issue is my point of engagement, I gotta figure this one out. I hope the people at Spec work with me on this. All three of my components came from different suppliers.

Skip White

 

[PBJ]

I have had several issues with low pedal engagement with spec clutches on t-56 transmissions...I am not sure of the reason but it has only happened with their clutches. It has only happened with aluminum flywheels also. I have had all of my issues on f-bodies with a t-56, but I have been lucky with all of my viper set ups. Talk to spec and see what they have say... The chatter will get a little better, but the neutral gear rattle will always be there with a aluminum flywheel. Hope that helps.
Later,
Joe

 

[SnakeEye]

Hmmm...can’t say that I’ve really experienced a problem with the stock clutch slipping since ditching the 3.07's for a more practical 3.55 gear set. And the engagement/disengagement of the stock clutch seems fairly precise which I do find attractive. Frankly, the stock gears are just too tall as the car is set from the factory in my opinion and I’m sure it does put quite a bit of stress on the clutch and may even cause some slippage with hard running. However, after the gear change 4th will bring you clear to 138mph through the traps so there is plenty of room for a good bit of modding before running out of gear and slipping of the clutch is all but none apparent so far as I've seen. I certainly am not wanting that frustrating rough on/off feel during engagement/disengagement that some custom clutch apps may lead to for a mostly street use SRT-10. Didn’t mean to wonder to far off topic here as I'm sure a clutch upgrade is fine for some, but for most, money may be better spent on a gear set first unless of course you've already installed a twin turbo system and have kept your 3.07’s. Then most certainly a clutch upgrade will be all of a necessity. Of course your mileage may vary but that's my take with about 2K on the clock so far. Can't help but dig this car more each and every day, even if in stock form it has just 500hp! LOL

 

[1TONY1]

Skip, I think you could solve your problem with a different disk. What is spec calling your current disk, a stage 3 ?

Hears my story:

Stock clutch with stock flywheel finally gives out due to age/et streets/hp.
So I get a Spec stage3 clutch/alum flywheel/pressure plate. Hooks up rock solid with tons of chatter. Also, what I call cam lope got worse.....the jerking motion of the car in 1st or 2nd gear when at neutral throttle, like when going through a parking lot. I ran one drag race and it was great, but the chatter was so bad it was embarrassing starting off from a stop in normal driving. I started to compensate by using more rpm and working the clutch in and out. I looked like I was just learning how to drive a stick.
So I changed to a Spec stage2 disk...same pp and flywheel. (at this time Spec had inspected the stg3 disk/pp/flywheel said they were fine) The chatter was almost gone, very livable in daily driving. Cam lope was about the same. I ran one drag race and there was no clutch slippage, but there was some problem with the clutch releasing.....I could not shift fast. If I tryed a quick shift it would just grind the next gear. At Bowling Green V10 nats I even changed transmissions to no avail.
So I Changed back to the stage3 disk, stock flywheel and also a new throwout bearing assemly. My quick shifting is back, the chatter is not quite as bad....I think due to the stock flywheel. Surprisingly there was not much change in the cam lope, maybe that was in my mind....I had also changed s/c pulley and injectors, that may have hurt drivability/cam lope. Could the shifting with the stage2 disk been the throw out bearing ? I don't know, but I don't think so.
I miss the aluminum flywheel and the stage2 disk, it seemed like the perfect street/strip set up. I will probably try this combo again to see if the problem was the throwout bearing, I would expect the shifting to be screwed again.
I am a Spec dealer and it seems like Specs standard answer is: Well, it shouldn't do that. They also say more miles = less chatter, this go around it may be calming some, but I believe the heavy flywheel helps it....Spec agrees.

 

[Skip White]

Thanks to all for the valuable info. These experiances of others are good to know. I will tone down my setup, and experiment with other setups. I do want to maintain good drivability with the car, but I'm finding my self getting used to some of it. The backlash/surging is a bit worse. It takes some fancy footwork with the throttle to control it.

Trial and error, and hearing from others is the key.

I think I will change out the disc, as it may lesson damage to the drivetrain. I would like more pp clamping to compensate. I did notice the oem disc has huge springs in the hub.

What Snake Eye said about the 3.07 is very much part of the problem. I've heard the chatter will also be reduced with a lower gear in the car. I can't waite till I get this done, and should have done it first anyway.


Thanks again to all that are sharing there experiances.

Skip White

 

[Skip White]

Did have air in the system. I do have much better disengagemnet, but not as much as oem. The installer had thought the one way check valve would prevent air from entering the system when uncoupled, but it did let air in.

The funny thing about this air problem is that, I did not feel to much difference in the pedel, as most people do. Maybe this is only when there is a lot of air in the system.

I did install the Energy Suspension trans. mount, and it feels better when shifting, and there is no transiant vibration at all. I've heard there would be some, but, none at all. The shifter doe's not torque over as much.

 

[Tom F&L GoR]

Is there a need for a hydraulic clutch system with a larger diameter clutch cylinder? It would increase pedal effort, but also increase slave cylinder travel for more engagement.

In my old kit car Cobra (sold to purchase Viper) I had a 12 lb flywheel and a McCleod 6 puck, no springs disc behind a 340 that idled pretty high. The pucks were ever so slightly twisted (purposely, I believe) so that it either rubbed or smoothed engagement, I don't know. Because it was a kit car, the mechanical clutch linkage I made up had multiple holes for the arms so I could easily change pedal effort/release bearing travel until it worked the way I wanted.

On my '94 there is no "Sean Roe clutch doohickey" so I added a second attaching point for the hydraulic cylinder. I made a duplicate of the OEM part, welded it onto the clutch pedal swing arm just below the OEM location, and with the math of leverage, it increased pedal effort by abotu 20%, but also increases hydraulic stroke 20%. Shifting is therefore quicker, since the release bearing travels more and faster, and when the adrenaline is running, you never notice the effort. Actually, you get used to it quickly.

Anyway, I need to repair third gear shortly and will have my tranny out. I'll take a look at the hydraulic cylinder and see if there is something that can be done about getting "more" out of it.

 

[Skip White]

I would love to get a little more disengagement, Tom's method sounds great, and if I could change the leverage point on the clutch pedal, that would be great, I don't mind a bit more pedal pressure. The Spec pp has les than the oem pp. I really dont like it that way.

Tom do you think the Roe pedal device will work on the SRT, or can one be made to do the same? I was thinking along those lines myself. But do you think the hydro system has a bit more stroke left in it, as this would be needed?

Skip

 

[Viper X]

Skip,
I have to agree with SnakeEye. I felt considerable "sponginess" almost to the point of slippage before changing to the 3.55's. Since changing gears, no problems with the clutch. A couple nights ago I was cruising home and a Turbo Carerra wanted to play. Dumped it into 3rd at about 75 and spun the rears. My wife asked what that smell was. I just answered that we sure smoked him didn't we honey, and she laughed. No clutch slippage, just spun the tires a bit and slayed him. I suggest you do the gear swap if your going to "swap" anyway, before you spend much more time with the clutch, as most of your issues may get a whole bunch better. Mine did. Good luck.

 

[Skip White]

Gears are going in this week. Does anyone know of a good guide on doing this? Any tips, or tricks to it. Most mechanics that have done rear ends have yet to do a setup like the SRT. I've had em done on GTS's but the SRT is so different I hear.

Any advise will be welcome.

Skip White