Replacing entire clutch system, and I mean EVERYTHING... suggestions? reccomendation?

[hpram99]

First a preface

98 GSX as seen in my profile (look for details) has been owned by an underage doofus that decided that everything was best when fubar. Well, almost everything.

This is, and will be, a project car and a daily driver. My wife will also drive it as much as me, she owned an RX-8 with a light flywheel, modified int/exh and misc. other crap. She know how to drive. However, she is also 5’2” and doesn’t have the leg muscle to constantly push a 3000+ lb clutch in rush hour on the way to work.

a. Goal here is around 350hp, but as efficient and reliable as humanly possible.
b. I am not car-stupid, please do not assume this, but I am dsm-specific inexperienced

Now. I am going to soon replace the entire clutch system, this includes Slave/Master cylinders, SS clutch line, Pivot ball, fork, bearing, and clutch (duh) and flywheel.

My questions are the following.

1. <S> What would be recommended for a very reliable, strong clutch that isn’t going to break my wife’s ankle and handle 300 hp. Also a fairly light flywheel to go with it</S>
2. Is there a master cylinder that eliminates pedal pump up? I would like to shorten the pedal throw, but am forced to have excessive amounts of free play just for the release valve. - I don't need an adjustment guide here
3. What other parts should I look at replacing/inspecting while the transmission is out of the car? This is a slightly big job, and I don’ want to do it more than once for something trivial. Including oil pan, output shaft seals, etc
4. With the idea of efficiency and reliability in mind, is there anything else that I should do to the car during the 2-52+ weeks it will take me?

 

[B-lackGSX99]

I drove an RX-8 for 2 years, so I can safely say that your wife will be just fine if you throw in an ACT-2600...it would be perfect based on your HP goals. It is a firm clutch, will outlast your car, and shouldn't be too much for her to handle. If she is extremely weak, go with a 2100, but it won't hold nearly as well.

 

[96gstdsm]

Yeah I have the ACT 2100 clutch. It is very nice, but I am not running much power at the moment. From what I gather it is good for around 350 hp. Maybe a little less, but that is what I thought. I also have the ACT streetlight flywheel and I would highly recommend it! It is not as light as the Fadanza ones, but will still rev it up a bit quicker. They are I believe 12 pounds compared to 8.5 with the Fadanza ones. I think the stock one is like 19 or 20 so still a big difference. If you would definitely be wanting to go above the 300 hp goal then I would say go with the ACT 2600 to be safe. I don't have personal experience with that one, but from what I hear it is not much heavier than the 2100. The 2100 feels very nice and is not hard at all the leg!

As for other parts top replace I would suggest, rear main seal, and axle seals since you'll have those disconnected already for the clutch job. Also make sure you get a throw out bearing that won't start rattling on you right away(the metal ones from earlier ACT clutches seem to be prone to that. The ACT clutch I got last summer came with a plastic sleeved one, which is the one you want, not the metal one.

 

[Eastwood95]

I think you're best option (as far as the clutch/flywheel) is the ACT2600 Kit with XACT Flywheel. I wouldn't bother with the 2100 on an AWD, especially when making decent power.....

http://www.extremepsi.com/store/customer/home.php?cat=458

This site has a few good deals for DSM's.....including the drivetrain

As far as the other parts you're looking to replace, NEW stock replacements should be fine(besides the SS clutch line). I would inspect axles and boots while they're out too.

Don't forget to pick out a good Tranny fluid. Redline MT-90, BG Syncromesh, and/or Mobil-1 75W/90 full synthetic (or any mix and match) will make that tranny shift like butter.

 

[delta448]

I would suggest at least looking at some other options before buying a 2600. Extreme Psi now sells a sprung 6 puck ACT disk in some of their kits. A sprung puck disk should be only slightly more chatter prone and slightly more "grabby". This would be another option for you since the 2100 with this disk is rated to 412 ft/lbs of torque. The 2600 plate with a full face disc is rated at less, to 400 ft/lbs and costs nearly $100 more. The difference in your choice would be whether you think you might decide to pursue high horsepower later, or would be more satisified with a lower pedal effort and mid-range power.

 

[hpram99]

I need to emphasize this more:

2. Is there a master cylinder that eliminates pedal pump up? I would like to shorten the pedal throw, but am forced to have excessive amounts of free play just for the release valve.

 

[Eastwood95]

The free play and pedal are adjustable.........

2G Pedal "Pump Up"
If you are fighting an inconsistent pedal adjustment in a 2G, adjust the upper pedal stop adjuster so that you gain additional free play at the top of the pedal travel. If this is your problem, you will notice that the pedal suddenly gets very tight and the release point will suddenly move up a lot, this is the cause.


2Gs need free play at the top of the pedal travel. If it is close to no travel and right on the edge, then it pumps up. Only 2Gs have a relief valve in the master cylinder that needs to be uncovered so fluid can go back into the reservoir on the clutch release. If not, it gets tighter and tighter and tighter. Then it may slowly relieve the pressure and it is back to normal. Just a 2G thing. You need more free play at the top of the pedal travel.

Left unchecked, the pedal will pump up more and more. The clutch will begin to slip since it is as if you are driving around with your foot on the clutch pedal. Also it plays hell on the crankshaft thrust bearings. The constant pressure pushes the clutch release bearing onto the clutch and flywheel. When centrifugal force throws the clutch release fingers outwards, they make additional pressure on the thrust bearings of the crank. This is an additional factor in short lived crankshaft release bearings and an additional potential cause for crankwalk.

Original link found here:
http://www.roadraceengineering.com/clutchandflywheeltech.htm

I haven't heard of a particular replacement master cylinder that eliminates pump up............

 

[hpram99]

I obviously must know what pedal pump up is if I've already adjusted the clutch, complained, and referred to the release valve -WHICH CAUSES PPU- limiting my freeplay adjustment. I'm sure I've probably read more of RRE's articles than you have.

I'll edit my original post to make this more clear.


Edit -
I forgot to thank all those who answered question #1 for me
I will replace my rear main seal while I'm there, and I'm going with a 2100lb ACT, I'm not too concerned about clutch/flywheel right now because I will probably convert to 6-bolt before I do any power mods, which means a new flywheel/clutch anyway. I was honestly surprised no one suggested a centerforce clutch, as they tend to have a fairly high clamping weight with less pedal pressure.

 

[hpram99]

Revised first post.

Most importantly I'm wondering if there is a master cylinder that eliminates pedal pump up? - I don't need an adjustment guide

 

[delta448]

Eliminate pedal pump up? -Yes, the stock 2G one. That's why it was designed with the relief valve.

If your goal is less free play, you'll probably have to either suffer more frequent pump up or pedal pumping to disengage. I'm not sure how you'd be able to swap to a non-relief valve master cylinder, but even if you could I'd expect a ton more problems than the stock system. Pressure in the line would be left uncorrected, whether high or low.

 

[bmoha2]

I gotta agree with Delta448. When I first started racing my Talon alot I ran into a slipping clutch and there was more freeplay at the top of the clutch pedal that I wanted or liked. I tried to adjust the clutch pedal assembly and consistantly got clutch pedal pump up. I had installed an act 2100 clutch and got a new stock flyhweel. I replaced the clutch actuator assembly, got a new pivot ball, reused the old fork, installed a new metal OEM thowout bearing and replaced the clutch master cylinder. I eliminated the slave cylinder on the front of the tranny with a one piece SS braided clutch line that goes from the clutch master cylinder to to clutch actuator and I'll be damned if the clutch doesn't work near perfect. It is now very very consistant. I just had to relax with my adjustments a little bit.

 

[hpram99]

I gotta agree with Delta448. When I first started racing my Talon alot I ran into a slipping clutch and there was more freeplay at the top of the clutch pedal that I wanted or liked. I tried to adjust the clutch pedal assembly and consistantly got clutch pedal pump up. I had installed an act 2100 clutch and got a new stock flyhweel. I replaced the clutch actuator assembly, got a new pivot ball, reused the old fork, installed a new metal OEM thowout bearing and replaced the clutch master cylinder. I eliminated the slave cylinder on the front of the tranny with a one piece SS braided clutch line that goes from the clutch master cylinder to to clutch actuator and I'll be damned if the clutch doesn't work near perfect. It is now very very consistant. I just had to relax with my adjustments a little bit.

This is more or less what I am doing, so it's good to hear someone else is having good results.

How long is your clutch pedal throw? Pedal Height? Free Play?

 

[bmoha2]

still has full length clutch pedal range of movement the pedal will go all the way to the floor, there is about an inch of freeplay at the top of the pedal stroke, the clutch ingages maybe three inches from the floor.

 

[DGajre777]

I would suggest at least looking at some other options before buying a 2600. Extreme Psi now sells a sprung 6 puck ACT disk in some of their kits. A sprung puck disk should be only slightly more chatter prone and slightly more "grabby". This would be another option for you since the 2100 with this disk is rated to 412 ft/lbs of torque. The 2600 plate with a full face disc is rated at less, to 400 ft/lbs and costs nearly $100 more. The difference in your choice would be whether you think you might decide to pursue high horsepower later, or would be more satisified with a lower pedal effort and mid-range power.

What ^^^ said.

I would put rear main oil seal on your list of things to replace.

 

[hpram99]

still has full length clutch pedal range of movement the pedal will go all the way to the floor, there is about an inch of freeplay at the top of the pedal stroke, the clutch ingages maybe three inches from the floor.

hmm.. I'm not happy with the clutch height, in most my cars I've been able to --safely-- reduce the clutch height and stroke. I don't want a clutch that engages quickly like a cintered disk, but I would like a clutch pedal throw that is only marginally longer than the clutch needs (about 5 inches). Is this possible? This is one of the reasons why I was asking about a master cylinder that does not have the problem with pedal pump up.

My RX-8 had a very small amount of pedal travel, I'm not sure exactly the measurement, but from the factory I think it was about 2" shorter than most cars.

 

[B-lackGSX99]

Oh, if only my GSX had the same clutch engagement as my old rx-8. I hear ya, buddy. Further, i'd be in heaven if it had half the smooth synchro too...after Redline fluids were placed in my rx-8, that thing shifted like butter nestled at 25 degrees celsius on a bed of silk suspended over the Aegean sea (pre-Mycenean Civilization).

I have tried desperately to replicate this in my GSX...have had no luck, I find everything is just too different. The ACT 2600 helped, but playing with pedal pump, etc...can't get the feel right, but have successfully shaved down the engagement range to where i'm at least happy with it. Best of luck.

 

[hpram99]

Oh, if only my GSX had the same clutch engagement as my old rx-8. I hear ya, buddy. Further, i'd be in heaven if it had half the smooth synchro too...after Redline fluids were placed in my rx-8, that thing shifted like butter nestled at 25 degrees celsius on a bed of silk suspended over the Aegean sea (pre-Mycenean Civilization).

I have tried desperately to replicate this in my GSX...have had no luck, I find everything is just too different. The ACT 2600 helped, but playing with pedal pump, etc...can't get the feel right, but have successfully shaved down the engagement range to where i'm at least happy with it. Best of luck.

hrm..

I realize the entire clutch system is different, so I don't expect to get the same results. I do however find it hard to believe that I can't shorten the clutch pedal that much. I've had shorter pedal throw in my MX-6.

I accept the fact that I'm probably not going to get what I'm looking for, but I'm curious: is there any specific reason that prevents you from lowering the clutch pedal that much?


Thanks for your input

 

[bmoha2]

His WRX has a really short pedal throw. I didn't like it. I thought it felt... I don't know cheap. Did the MX6 has a similar setup? Hydraulic clutch? Was it a push vs pull clutch engaement? I gotta agree with you man, I felt very frustrated with my clutch and it setup when I first got the car and started racing it. By trial and error and continuous minute adjustments I finally got it to the point that it is now which is very consistant.

 

[bmoha2]

I experienced all of the problems you were having. I would try to adjust the pedal with almost zero freeplay at the top of the pedal stroke and then run it and within a few minutes the clutch would be fully pumped up and slipping. i guess you have to go with the happy medium. Now the clutch is very consistant like I said and I have really gotten used to it. In fact, now, when I drive other cars, their clutches feel very weird to me.

 

[hpram99]

B-lackGSX99 : Could I get more info on what you did to get the clutch pedal lower?

I'm still debating between the 6 puck sprung clutch, or OEM style clutch disc (for the ACT2100 pressure plate)

The stock flywheel shouldn't have any problems handling the 6 puck without blowing up, I'm considering it because it doesn't have any marcel, which means less pedal, but if other factors are going to prevent me from using that short throw clutch, then I see no reason to jus go with an organic OEM style disc without the chatter problems and easier slipping...

 

[DSMULATOR]

On the Road Race Engineering web site they have a good article about shimming the ball on the clutch fork too. I had to do that when I put my 6 puck in. I didn't want to short cut it and get a longer rod for the slave cylinder.

 

[hpram99]

On the Road Race Engineering web site they have a good article about shimming the ball ...

Yes, I fully intend on doing this, however, I don't think this will help very much with what I am trying to do here. But thank you for the reminder.
I've started the teardown and I'm starting to see a lot more problems with this car, a few mechanics did some pretty lazy stuff down there....


B-lackGSX99: I'm still waiting for your reply!!!