I hope I can answer some questions you may have if you are considering a PowerTrain Technology 7.25" Power-V racing clutch for your daily driven 2G.
How about if I answer this? “I'm curious to know what it’s like to drive in heavy traffic or parking with a twin disk clutch.”
IMHO, the PowerTrain Technology 7.25" Power-V racing clutch (PTT) is a joy to daily drive. Parallel parking is the same as a stock clutch. However, I needed to learn about the nature of this clutch and gain some skill (see paragraphs below). Also, it is noisy, stalls easily and may not last long in a daily driver. Eventually, driving on the PTT becomes a skillset, something that I became used to and now it’s one of those things I do automatically, like shifting & using my turn signal. It always, most importantly, put a huge smile on face after every driving opportunity.
First the “negatives”:
* I could have sworn there were pieces of loose gravel being ground up by gear teeth (see harmonics points a) & b) below)
* driveline harmonics can set off the CEL (DTC code says it’s a misfire)
* harmonics occurs when:
a) lightly loading the transmission, for example, while coasting in gear on flat roads and/or slight downgrades or
b) decelerating
* if the harmonics are allowed to grow in intensity, then the knock sensor retards ignition timing (learn to foresee this and get ready to either depress the clutch pedal or give it some gas). This only had to happen to me once, and I have never let it occur since.
* in my case, a Fluidampr p/n 630701 harmonic dampener did not eliminate harmonics, but reduced it by 75% and rock crushing noises are now very low and muted
* stalls easily
* sounds like dishes rattling together when the clutch is disengaged (I personally don’t find this to be a negative)
* chair scraping sounds are made whenever engine and transmission RPMs aren’t matched on a downshift (I personally don’t find this to be a negative)
* I found myself concentrating more rather than driving along distracted (I personally find this to be an advantage) – matching engine/trans RPMs, listening for & avoiding harmonics, etc.
* small clutch engagement window, about 1/2” to 5/8”
* from a dead stop, it requires slipping the clutch 1,750RPM to 2,000RPM on level roads
* clutch started to slip
1 at 12,000 Kilometers (7,440 miles) of daily driving
*
Updated 31 October 2009 when these clutches begin to slip, it rapidly deteriorates
*
Updated 31 October 2009 compared to a stock pressure plate, an extra 10 lbs. to 12 lbs. of foot pressure is needed to depress the clutch
In return for all of the above, I got these advantages:
* fast shifts
* smooth shifts
* no missed shifts
* always goes into gear no matter what the engine's RPM or road speed
* throttle response - blip the throttle and the engine responds almost as quickly as a motorcycle's does
* no chatter
* no stumbling
* raspy sounds of the PTT disengaged, while up shifting or parallel parking is just different from the sounds other cars make. Yes, I like the sound of twin disk clutches. I listen for other cars if they have it.
* main reason I chose a twin disk clutch – the PTT is less likely to over burden the crank shaft thrust bearing & crank walk the 4G63 engine
1 I’ve probably worn one or both PTT organic clutch disks to less than 0.185” (0.20” new). PTT’s web site says that QuarterMaster, AP Racing & Tilton clutch disks can be used in their twin disk setup. PTT e-mailed saying they will rebuild the twin disk for free; there will be no labour charges.
Configuration & operating environment notes:
The PowerTrain Technology 7.25" Power-V racing clutch is supposed to require a shorter range of movement by installing a slave cylinder from an Isuzu truck. I used a new 2G Mitsubishi Eclipse OEM slave and did not grind the new OEM fork or shim the new OEM pivot ball to make the twin disk fit/engage/disengage. The slave cylinder restrictor and accumulator (fluid collection unit) were removed. A single, steel braided line from RRE replaced the OEM rubber lines.
Update 31 October 2009 I provided a new PTT throw out bearing back in October 2008, but something else had been substituted as the mechanic at the time said the PTT TOB “exploded”. The substitute TOB’s height was shorter and had less metal overall than another new Mits OEM unit I just had installed (by another shop). This could explain why I could get by on an OEM TOB and did not need an Isuzu slave cylinder.
The cruise control switch was backed out all the way until I could not start the car (safety switch is in there to prevent starting the Talon while in gear). The switch was then moved forward, but only enough to start the Talon. This placed the clutch pedal at its highest point, 6 1/2" from the floor. According to my shop manual, this is still not the specified 7” from the floor. Since I don't like the pedal that high, I put it back down to 5" off the floor (estimated). There is one more step to do, please see Jack’s Transmission’s video
http://www.youtube.com/watch?v=vYJxQyjIhUwWhen the clutch was new, I revved the motor to 5,500RPM while in first gear, clutch pedal pressed in a down, or clutch disengaged position with the e-brake off and the car did not creep forward. I know this test should be pushed to 7,500RPM, but an unloaded motor spinning at red-line is just not my cup of tea.
For this review, a point to consider is that my Talon is a full weight, stock powered AWD with a Quaife ATB front LSD & an EVO 1st gear. The EVO is 10% taller than stock. Jack’s Transmissions also double synchro’d 1st, 2nd & 3rd gears and upgraded the trans for the twin disks’ harmonics.
I love that that EVO 1st gear! According to my 1995 sales brochure, stock Turbos make a peak 214 ft. lbs. at 3,000RPM. By the time the clutch is let out fully at 2,000RPMs, the 4G63 is less than 1,000RPMs from peak torque by the time the car begins to inch forward. The car wants leap forward all the time.
I can usually be found during rush hour inching up to four way stops on mountainous roads and also crawling slowly to queue up for bridge traffic. The twin disk is always being slipped. Sometimes I will smell clutch burning while stop & going.
Short clutch life requires steep grades + stop & go traffic + light flywheel + taller 1st gear + Quaife front/4 spider centre/viscous rear LSDs + full weight AWD.
Summary:
I have not set off the CEL for a long time. Even my wife doesn’t set off the CEL anymore (she never got the 2G to retard the ignition). Both of our skills using the PTT had to improve and that was all.
Remember, as always, your mileage may vary from my observations/experiences.
Updated 19 Dec 2009 Crank shaft thrust bearing wear with the PTT was 0.002” after 12,000Kms. The crank shaft end-play was 0.003” when the PTT went in and 0.005” shortly after the PTT was pulled out. This measurement was done by a Mitsu dealer.
