ACT Heavy Duty or Xtreme?
08-27-07, 03:12 PM
#1
ACT Heavy Duty or Xtreme?
I should ask in the 2nd gen section. 
How heavy is the pedal with an ACT Xtreme pressure plate? How does it compare to their Heavy Duty and stock?
I'm looking at these kits with the Performance Street disc. http://www.advancedclutch.com/produc...0Turbo&go=true
I do not want a puck type because it's for the street.
How heavy is the pedal with an ACT Xtreme pressure plate? How does it compare to their Heavy Duty and stock?
I'm looking at these kits with the Performance Street disc. http://www.advancedclutch.com/produc...0Turbo&go=true
I do not want a puck type because it's for the street.
08-27-07, 03:42 PM
#2
I have the 6 puck in my TII and it's STIFF compared to my Exceddy Stage 2 clutch in the NA. Seriously ON or OFF with no compromise. feathering it is possible but it's a bitch especially if you get stuck in traffic.
Once the clutch is engaged though, it's clamped on and it feels nice.
Once the clutch is engaged though, it's clamped on and it feels nice.
08-27-07, 04:00 PM
#3
don't know if this helps you any:
http://www.advancedclutch.com/store/...equirement.pdf
My train of thought: if you have a 20B (assuming by your name) then you'd better go with something that will hold up.
http://www.advancedclutch.com/store/...equirement.pdf
My train of thought: if you have a 20B (assuming by your name) then you'd better go with something that will hold up.
08-27-07, 04:24 PM
#4
Lives on the Forum
Here's my take on it...
Too many people are having problems with the Xtreme pressure plate.
Either hydraulics are failing, or the pivot ball breaks.
I think the PP is just too much for the stock clutch actuation systems.
I've been trying to find someone who will make an upgrade pivot ball...
You're right about the puck discs.
It's too much shock to the system and mounts and drivetrain components tend to fail.
I would still recommend trying the HD PP with the street disc.
Although ACT rates this combo for 337(?) lb-ft, they seem to hold up fine with 400hp FC's with 13BT's (you looking for something for the 20B?).
If it's 20B related, I would recommend going with a twin disc, if you're trying to keep it streetable.
OS Giken makes one, and if a brand new kit is too much shock to your wallet, used ones come up regularly on eBay via J-spec engines for much less - around $500.
This is a good deal for what you are getting, especially since this includes the flywheel.
-Ted
Too many people are having problems with the Xtreme pressure plate.
Either hydraulics are failing, or the pivot ball breaks.
I think the PP is just too much for the stock clutch actuation systems.
I've been trying to find someone who will make an upgrade pivot ball...
You're right about the puck discs.
It's too much shock to the system and mounts and drivetrain components tend to fail.
I would still recommend trying the HD PP with the street disc.
Although ACT rates this combo for 337(?) lb-ft, they seem to hold up fine with 400hp FC's with 13BT's (you looking for something for the 20B?).
If it's 20B related, I would recommend going with a twin disc, if you're trying to keep it streetable.
OS Giken makes one, and if a brand new kit is too much shock to your wallet, used ones come up regularly on eBay via J-spec engines for much less - around $500.
This is a good deal for what you are getting, especially since this includes the flywheel.
-Ted
08-27-07, 04:36 PM
#5
Yeah, it's for the 20B. I'm asking in the 2nd gen section because I knew you guys had more experience with strong clutches than the 1st gen section.
The project car is a 1st gen, so just think of it as a small GXL or something.
The tranny is a 1st gen with big tooth gears ('81-'83). They seem to give less trouble than the smaller toothed '84-'88 NA. Plus the car is lighter, which helps a bit.
I don't want a digital clutch. There's got to be something between on and off that will handle the torque and not shock the drivetrain.
I just found spec clutches. Some of those look promising. Stage 2 or 3 would probably suit me.
Ted, the engine will start off NA and I'll progress from there. It's currently unopened and needs a rebuild. Since it's an early engine (#756), it's got the weak side plates and probably the weak shaft. I won't know which shaft it's got until I open it.
I did see signs of a possible factory rebuild. Things like scratches all over the oil pan mounting surface on the bottom of the legs. Or maybe just the pan was resealed? All rotor housings and side plates have the same numbers stamped.
The project car is a 1st gen, so just think of it as a small GXL or something.
The tranny is a 1st gen with big tooth gears ('81-'83). They seem to give less trouble than the smaller toothed '84-'88 NA. Plus the car is lighter, which helps a bit.
I don't want a digital clutch.
There's got to be something between on and off that will handle the torque and not shock the drivetrain.I just found spec clutches. Some of those look promising. Stage 2 or 3 would probably suit me.
Ted, the engine will start off NA and I'll progress from there. It's currently unopened and needs a rebuild. Since it's an early engine (#756), it's got the weak side plates and probably the weak shaft. I won't know which shaft it's got until I open it.
I did see signs of a possible factory rebuild. Things like scratches all over the oil pan mounting surface on the bottom of the legs. Or maybe just the pan was resealed? All rotor housings and side plates have the same numbers stamped.
Last edited by Jeff20B; 08-27-07 at 04:46 PM.
08-27-07, 05:22 PM
#6
I haven't had a problem with my clutch yet (less than 20K on it and was broken in properly). I don't really do hard launches or excessively beat on it. My tranny, engine and diff mounts have been upgraded (i can't remember whether I used stock diff mounts though but for sure I got the stiffer mounts for the engine and tranny)so I really don't know about the failing mounts.
I'll double check the hydraulics after I finish my turbo install and get back to you all but unless you see daily bumper to bumper traffic the puck clutches don't seem too bad (your leg gets a workout though). I didn't/don't drive my TII everyday so I rarely saw bumper to bumper traffic.
I'll double check the hydraulics after I finish my turbo install and get back to you all but unless you see daily bumper to bumper traffic the puck clutches don't seem too bad (your leg gets a workout though). I didn't/don't drive my TII everyday so I rarely saw bumper to bumper traffic.
08-27-07, 05:29 PM
#7
I had the ACT HD pressure plate and HD organic disc and if I tried to use the clutch at all to limit wheelspin in 1st on warm tires it would get hot and slip through the rest of the gears (245mm wide RA-1).
I spoke to someone at ACT and they didn't think that was abusive, but that I just needed a stronger clutch.
They really recommeded the Xtreme pressure plate and an organic disc as it is more streetable and easier on the flywheel, but I went with the sprung 6-puck copper clutch and retained the HD pressure plate as the clutch pedal with just the HD is very stiff and I have already had to replace all the hydraulics and the pivot ball just for it.
Well, it seems I will never get the puck clutch to engage smoothly every time when babying it around town no matter how much I practice, but it is very smooth and repeatable when launching and has very positive engagement between shifts.
Now, I never had a problem with the HD and organic disc combo when I was on street tires (wheelspin 1st-4th) or even 225 RA-1 (wheelspin 1st-2nd) as the tires limited the engine torque that could be applied to the road.
If you are NA 20B and stock body 1st gen the HD and organic disc will most likely work great as you won't have turbo torque to deal with yet and any tires that will fit under there will spin easily anyways. Once you go turbo it will probably be time for a new clutch anyways (and widebody kit) and you will have the engine out and apart to upgrade it anyways.
I spoke to someone at ACT and they didn't think that was abusive, but that I just needed a stronger clutch.
They really recommeded the Xtreme pressure plate and an organic disc as it is more streetable and easier on the flywheel, but I went with the sprung 6-puck copper clutch and retained the HD pressure plate as the clutch pedal with just the HD is very stiff and I have already had to replace all the hydraulics and the pivot ball just for it.
Well, it seems I will never get the puck clutch to engage smoothly every time when babying it around town no matter how much I practice, but it is very smooth and repeatable when launching and has very positive engagement between shifts.
Now, I never had a problem with the HD and organic disc combo when I was on street tires (wheelspin 1st-4th) or even 225 RA-1 (wheelspin 1st-2nd) as the tires limited the engine torque that could be applied to the road.
If you are NA 20B and stock body 1st gen the HD and organic disc will most likely work great as you won't have turbo torque to deal with yet and any tires that will fit under there will spin easily anyways. Once you go turbo it will probably be time for a new clutch anyways (and widebody kit) and you will have the engine out and apart to upgrade it anyways.
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08-27-07, 05:43 PM
#9
phoenix7, my clutch master and slave both leak and the flex hose is showing age. Since I have to replace or rebuild them anyway, would it be good to get a 2nd gen slave? It's the same price as the 12A slave. I like the ss braided flex lines at Mazdatrix.
I have a spare 2nd gen slave that I tried on a friend's 1st gen the other day and it felt fine. His flex hose cracked and I needed something right then. Maybe it's my imagination but it seemed to feel better than his stock slave. The car just got a new RB streetstrip pressure plate and HD clutchwith resurfaced stock flywheel. The push rod was not adjusted yet.
I want to eventually daily drive the 20B so it needs a good streetable clutch that won't kill my leg in bumper to bumper traffic. I already got to walk funny for a few days after driving my MG Midget 13B project around the block a couple times. Stock MG master and '79-'80 RX-7 slave; not a good combo. That's why I picked up the FC master and slave set last year. The pressure plate is a Daikin and the disc is stock. I don't want a repeat of the MG one legger workout routine. Heh.
I have a spare 2nd gen slave that I tried on a friend's 1st gen the other day and it felt fine. His flex hose cracked and I needed something right then. Maybe it's my imagination but it seemed to feel better than his stock slave. The car just got a new RB streetstrip pressure plate and HD clutchwith resurfaced stock flywheel. The push rod was not adjusted yet.
I want to eventually daily drive the 20B so it needs a good streetable clutch that won't kill my leg in bumper to bumper traffic. I already got to walk funny for a few days after driving my MG Midget 13B project around the block a couple times. Stock MG master and '79-'80 RX-7 slave; not a good combo. That's why I picked up the FC master and slave set last year. The pressure plate is a Daikin and the disc is stock. I don't want a repeat of the MG one legger workout routine. Heh.
08-27-07, 06:00 PM
#10
1. I'm not familiar enough with the SA/FB parts to know whether or not the FC units will work as well or better. Sorry. I have TII tranny and clutch hydraulics on my car.
2. A SS hose might be better to prevent the flex but you might want that SOME of that flex as opposed to it leaking at the slave due to excessive pressure (maybe one of the gurus might be able to elaborate/correct any/all misconceptions on this)
3. You WILL get a workout with the puck and you'll have ONE mean looking calf but you get used to it after while. The only thing I'm thinking could be a problem is if you have too much torque on a clutch that can't take it. Do you plan on staying NA for a while?
2. A SS hose might be better to prevent the flex but you might want that SOME of that flex as opposed to it leaking at the slave due to excessive pressure (maybe one of the gurus might be able to elaborate/correct any/all misconceptions on this)
3. You WILL get a workout with the puck and you'll have ONE mean looking calf but you get used to it after while. The only thing I'm thinking could be a problem is if you have too much torque on a clutch that can't take it. Do you plan on staying NA for a while?
08-27-07, 06:08 PM
#11
I'm replacing all the clutch hydraulics so that will take care of that end of the spectrum.
It sounds like I might need to worry about the pivot ball then, even with just the ACT HD pressure plate. The Xtreme would be too much for 1st gen parts, like the pedal arm itself, I'd think. It's easy enough to bend (adjust) left and right just by grabbing and pulling it.
One thing I could do to strengthen the pivot ball would be to swap in a cast iron slider hub. I'm sure the stock aluminum one is worn a bit. I'll do that after I pull the 12A. Gotta replace the shifter centering spring too. Might as well pull the tranny and replace the rear seal while it's out.
It sounds like I might need to worry about the pivot ball then, even with just the ACT HD pressure plate. The Xtreme would be too much for 1st gen parts, like the pedal arm itself, I'd think. It's easy enough to bend (adjust) left and right just by grabbing and pulling it.
One thing I could do to strengthen the pivot ball would be to swap in a cast iron slider hub. I'm sure the stock aluminum one is worn a bit. I'll do that after I pull the 12A. Gotta replace the shifter centering spring too. Might as well pull the tranny and replace the rear seal while it's out.
08-27-07, 06:20 PM
#13
The car currently has a 12A with a mild port job. All my other rotaries have been 13Bs so this 12A feels lacking in the low end. The 20B will take care of that.
The 12A has a new RB light steel flywheel and a worn clutch. The pressure plate is stock and honestly feels a little weak to me. The leaky clutch hydraulics cause the engagement point to vary. The worn disc allows for some pretty wild chatter sometimes. It was unpleasant to drive because you could never count on decent launches. Even starting smoothly was a chore. The light steel actually improved driveability - it was actually worse with the stock flywheel.
I've thought about sticking with the light steel flywheel but if aluminum would be more fun, I'd rather go aluminum.
phoenix7, I could stick with stock style clutch hydraulics. It's not a big deal to me. The braided flex hose is a good idea and improves pedal feel/feedback. That's high on the list as you can understand. I plan staying NA for a while.
The 12A has a new RB light steel flywheel and a worn clutch. The pressure plate is stock and honestly feels a little weak to me. The leaky clutch hydraulics cause the engagement point to vary. The worn disc allows for some pretty wild chatter sometimes. It was unpleasant to drive because you could never count on decent launches. Even starting smoothly was a chore. The light steel actually improved driveability - it was actually worse with the stock flywheel.
I've thought about sticking with the light steel flywheel but if aluminum would be more fun, I'd rather go aluminum.
phoenix7, I could stick with stock style clutch hydraulics. It's not a big deal to me. The braided flex hose is a good idea and improves pedal feel/feedback. That's high on the list as you can understand. I plan staying NA for a while.
08-27-07, 06:29 PM
#14
The '81-'83 big gear trannies are pretty good. My friend has one with a supercharged 13B in his '83 and has had that tranny for over ten years.
A guy in Aus has a 20B in his '83 with a 12Aturbo tranny and it held up fine all while it was NA and is till holding up with a turbo. I think his most recent posted dyno result was around 400HP.
It's rumored the 12A turbo trannies are stronger, but it's just a rumor. I've never seen the internals side by side.
I don't plan to abuse it. If it does break, it's not a problem to get another and toss it in. Its location in the car will stay stock. It's so much easier to deal with parts in their stock location than if you relocate stuff fore and aft. Yeesh!. Been there, done that.
If I got a T2 tranny, it's a one time expense, but probably not necessary until after I go turbo. Why change it if it ain't broke yet?
A guy in Aus has a 20B in his '83 with a 12Aturbo tranny and it held up fine all while it was NA and is till holding up with a turbo. I think his most recent posted dyno result was around 400HP.
It's rumored the 12A turbo trannies are stronger, but it's just a rumor. I've never seen the internals side by side.
I don't plan to abuse it. If it does break, it's not a problem to get another and toss it in. Its location in the car will stay stock. It's so much easier to deal with parts in their stock location than if you relocate stuff fore and aft. Yeesh!. Been there, done that.
If I got a T2 tranny, it's a one time expense, but probably not necessary until after I go turbo. Why change it if it ain't broke yet?
08-27-07, 07:08 PM
#15
No hydraulic hose- be it SS or stock rubber- is meant to act as a relief valve for the cylinders.
There is no "excessive pressure"- the system will only deliver what it was designed for and that is a function of cylinder diameter and piston travel.
08-27-07, 07:14 PM
#16
It sounds like I might need to worry about the pivot ball then, even with just the ACT HD pressure plate.
08-27-07, 07:32 PM
#17
my train of thought is: a rubber hose WILL expand under pressure while a SS line will not. THIS can affect the pedal and pressure feel of it. would it also affect the amount of pedal travel?
If the rubber hose expands that means that the clutch has to go down further than if the line was steel right? Now, will the pressure that the rubber line withstands (which obviously meets auto standards) be too much for the cylinder if it has SS lines (which transfers all the pressure to the slave)?
I might overthink things sometimes.
If the rubber hose expands that means that the clutch has to go down further than if the line was steel right? Now, will the pressure that the rubber line withstands (which obviously meets auto standards) be too much for the cylinder if it has SS lines (which transfers all the pressure to the slave)?
I might overthink things sometimes.
08-27-07, 07:41 PM
#18
In this case, I think you are.
The difference in expansion rates between a new rubber hose and a new SS hose would be miniscule, especially over the short length of the hose in question.
You seem to be equating what we call SS lines with a hard metal line, which of course, it is not. Our SS lines flex/expand too, you know.
The difference in expansion rates between a new rubber hose and a new SS hose would be miniscule, especially over the short length of the hose in question.
You seem to be equating what we call SS lines with a hard metal line, which of course, it is not. Our SS lines flex/expand too, you know.
08-27-07, 07:43 PM
#19
Here's my take on it...
Too many people are having problems with the Xtreme pressure plate.
Either hydraulics are failing, or the pivot ball breaks.
I think the PP is just too much for the stock clutch actuation systems.
I've been trying to find someone who will make an upgrade pivot ball...
Too many people are having problems with the Xtreme pressure plate.
Either hydraulics are failing, or the pivot ball breaks.
I think the PP is just too much for the stock clutch actuation systems.
I've been trying to find someone who will make an upgrade pivot ball...
HOLY CRAP!!! I thought I was the ONLY ONE!!
I have broken TWO freakin pivot ***** in the last YEAR!!
08-28-07, 11:54 AM
#23
Wow, with so many T2 pivot ***** breaking, I bet they're even easier to break in 1st gen trannies. However since the pivot ball bolts to the slider hub, if I go with the iron version, at least the threaded hole won't get damaged...
Nah, I'd rather not risk it. I'll just go with the HD pressure plate if I choose ACT.
If I choose Spec, which stage should I get?
To get an idea for how much torque my engine might have, here's RETed's dyno run on the NA 20B he was working on a few years ago.
His engine was totally stock (never opened) at that point. Mine is basically worn out and needs a rebuild. I figured I'd do a little porting while it's apart. The HP should go up, as well as the torque peak. I'm not sure how much though. I want to keep the awesome low end it currently has, so the porting will not be large.
Nah, I'd rather not risk it. I'll just go with the HD pressure plate if I choose ACT.
If I choose Spec, which stage should I get?
To get an idea for how much torque my engine might have, here's RETed's dyno run on the NA 20B he was working on a few years ago.
His engine was totally stock (never opened) at that point. Mine is basically worn out and needs a rebuild. I figured I'd do a little porting while it's apart. The HP should go up, as well as the torque peak. I'm not sure how much though. I want to keep the awesome low end it currently has, so the porting will not be large.