When I got the car, it ran good and I was fairly satisfied. It did miss shifts every so often. I suspected the clutch and as a test I tried the launch described in this PDF doc where I performed this only once. The car laid down two patches of rubber quite nicely so it didn’t seem like the clutch. I tried to learn the traits of the miss shifts. Above about 5000 RPM where hyper shift should occur, many times the shift would occur just right and sometimes it would have a delay of up to a few seconds. Below 5000 RPM, everything was fine.
Reading anywhere online I could find about this, I started to realize this is the behavior of the transmission controller and decided that I needed a new clutch. I really wish Magneti Marelli used a mis-shift counter to disable hypershift altogether when the it reaches a certain count but nope, it’s just random.
So, the clutch install is pretty expensive and I heard many great things about the dual plate clutch. I read about the installation and realized why the labor is so high. I remember the Porsche 928 I had where there was a removable bell housing segment between the engine and torque tube. I wish the Vantage had this. The funny thing is that on the 928, the new models had the upgraded single disc clutch which for the Vantage would be the opposite.
So the dual plate clutch was the first modification I made and what a difference. No more missed shifts and the engine was really responsive. I checked the total surface area of the old vs new clutch.
The AMR dual plate clutch has 27% more surface area.
| ID | OD | ID Area | OD Area | Diff | Total | |
| Old | 7.11 | 10.51 | 39.70 | 86.76 | 47.05 | 94.10 |
| New | 5.79 | 8.45 | 26.33 | 56.08 | 29.75 | 119.00 |
| % diff | 26.46% |
The weight savings is 5.3 lbs.
| Weight | Old | New | Diff |
| Clutch Pack | 21.6 | 17.6 | 4 |
| Fly Wheel | 16 | 14.75 | 1.25 |
| Total | 5.25 |
Before I changed the clutch, I scouted eBay for a good deal on some 200 cell cats. I found a set of Harrison’s for $500 and then sometime later I found a $200, practically new muffler in case the cats were too loud with my Tubi which that came with the car.
So a few months after I replaced the clutch and was comfortable with the car running normally, I bought the VAP ECU tune from Peninsular European Car Service. Man that really made a difference. So with the clutch and this tune, I really love how the car launches. I wish there was more information about what I actually bought (like a plot of the new vs old throttle map) and exactly what changes where made but that’s quite alright because I’m very happy with it.
The Harrison Cats take about an hour to install.
The Vibrant 1463 gaskets I bought from Veracious Motor Sports ($15.47 inc. S&H for 2). The SS bolts from ebay were $11.47. They are M8-1.25 x 35mm. I used the existing nuts.
I found that around 3000 RPM, it created this thrashing sound and overall was going to be too loud to drive without getting too much attention from the cops. Also, I couldn’t tell any difference in performance. So I pulled them off. I may try again sometime and install the OEM muffler but the sound with the Tubi is supreme.
At one point just after I bought the car, I found a set of used VAP headers, cat deletes and a VAP tune on Craigslist. I was reluctant to get the headers and didn’t want the deletes so I never struck a deal with the seller. I prefer the 4-2-1 headers for the better low end torque and overall driveability. I spoke with a co-worker that suggested the exhaust odor is the reason he uses 200 cell cats. The only thing I could use was the VAP tune.
I don’t think I’m going to get much more performance from the car so I’ll need to focus on wheel upgrades, R-Comp tires, racing brake pads and track days (which I have yet to attend).
After the clutch has been broken in. Performance modifications: Clutch & Tune.
Started June 2020