Schmidlap wrote:
mguar wrote:
Jaguar V12's can be great affordable race cars... Dump the auto trans and adapt a T5 and you will have the best performance improvement imaginable.
You can gut it to around 3000#'s and maybe as low as 2500#'s if you know how to make fiberglass molds
500 hp, 2500pounds and I'll have less than a grand in it..
Can you give more details about adapting the T5 to the V12? Which T5 would you recommend? I assume you're using a World Challenge version, but would you recommend the Camaro or Mustang version? What about clutch, pressure plate, bellhousing adapter etc? What are you doing for a clutch pedal - just sourcing a pedal from a Euro manual trans Jaguar? Terry's Jag Parts is supposed to sell a conversion kit, but I only see stuff for the inline 6 on their page, and it's not cheap. I'd love to do a twin-turbo V12 with a 5 speed in an XJ12C and do it up like the Broadspeed Cars .
Details about weight reduction would be appreciated too. The only thing I've seen about weight reduction in an XJS is from the JagLovers XJS Online Book where they throw out a speculation of "cutting 800lbs out of this car would let it terrorize Corvettes. That's if you could live without a radio, power window motors, power locks, stereo, 5mph bumpers, etc." They also talk about replacing some of the heavier engine accessories like the starter with lighter weight components but they don't get into specifics. I'd love to learn how to cut 1000 pounds out of these cars, so any info you can give would be really appreciated.
Any pics of your car? Are you going the twin turbo, 5 speed route?
I'm off to scout Craigslist for cheap Jaguars!
Thanks,
Bob
OK take a V12 empty block, find a 3 inch diameter tube about 5 feet long. (roll it on a big piece of glass to ensure it's straight) Use the bellhousing from the early V12's with Borg Warner automatics.. (1971-1979-80). Grab a T5 empty case.. Using the stock bearings bolt the tube into the make a set of "bearings" for the T5 case (I turned mine out of oak on a wood lathe but you can use a metal lathe, and turn them out of plastic, aluminum, steel, gold,silver platinum
That will align everything and then all you need to do is measure to make sure the length is correct.. make the adapter between the Borg Warner case and the T5 that thickness.
You can use the stock Jaguar flywheel There are a few of those around or aftermarket flywheels. (I found an aluminum that was removed because it was noisy due to extreme lightening).. Use the clutch disk from the transmission you selected.. depending on who makes the flywheel it's either a 10&1/2 or 11 inch disk.. (unless like me you are using a 7&1/4 in. triple disk for racing)
Use the hydraulic throw out bearing (I bought mine form Tilton)
As for which one? Well how much power are you going to make? Plus how much weight will you have? Less weight = cheaper tans. Less power=cheaper trans. a stock motor in a lightened XJ-S you can get by with the T5 from an S10
Don't waste money for a 6 speed.. it's a double overdrive and you won't want that unless you never intend to race it.. Most post 1980 XJ-S's had 2.88 rear end ratio and double overdrive will have the engine turning at idle in 6th gear.
Clutch pedal can be adapted to the stock brake pedal assembly. Weld an aluminum tab and use another brake pedal.. looks original.. (Ask Bob Knodt about details.. his idea)
Broadspeed never raced the XJ-S. They raced the XJ-C V12 TWR and Group 44 are famous for the XJ-S's they raced
OK weight reduction.. dump all the interior stuff. Seats carpet, sound deadening, A/C heater etc.. front and rear bumpers weight a lot! Go to a racing seat.
The stock hood and trunk lid are very heavy for what they do.. Make fiberglass splash molds off them and if on a really tight budget use cloth hand layups. That will save you more than 1/2 the weight of the stock hood/trunklid. If you have a little more money (not a lot) shop around for Aircraft grade Carbon Fibre that has date expired.. (you can find it in any city that has an airline hub in it where they do full maintenance) The hood can weigh about 20 pounds and the trunk lid will be about 15 pounds.. The doors are about 100 pounds and the replacement skin will weigh about 4 pounds.. Only do if you have a roll cage with side bars for protection.. The real savings are with fenders (if they are flared or blistered for big racing wheels.. By the time you use enough bondo to cover the wheels and make things look decent each fender weighs close to 40-60 pounds.. splash molds and then the finished part weighs about 8. (you'll only save about 6 pounds over stock if nor flared)
Vacuum bag them and save even more weight.
Speaking of rollcage if you get the weight down to around 2500#'s most rules allow a lighter tubing which will save weight.. Use DOM steel if on a budget and Chrome Molley if not. The cage from stock cars magazines for a Camero will adapt if you don't have access to a tube bender.. Easiest way to install the cage is cut the roof off there are seams at the top of the windshield post and at the top of the glass (melt the lead out first). put the cage in and then weld the top back on..
Get rid of the glass. replace it and the frames, power windows with polycarbonate. paint the edge of it black and it will still look remarkably close to original.. The front windshield could be polycarbonate but expect to replace it every year or so plus you'll need to use tear offs.. But you'll save some weight so it might be worth it to you..
On the engine replace the stock alternator with one of those light little peanut ones the Japanese cars use..
the starter should also be one of those gear reduction starters that so many people sell.. I had to adapt a Tilton back when I started racing but now there are several sources for them..
Headers are a waste of money.. (unless you are on a unlimited budget)
I did the twin turbo route a decade ago as well and before that the Webers, headers (proper tuned length real headers, not just the tubular exhaust manifold so many sell)
Bottom line is there are budget ways to make power and lose weight but if you are only willing to buy stuff it get's real expensive real fast..
I looked at selling carbon fibre parts and by the time I crated and shipped stuff it cost a fortune. I could make splash molds for about $50 each and they were good for 2-3 parts before it took more time to repair than remake.. I bought a roll of expired carbon fibre for $400 and used enough to make the XK-E hood I wanted plus the trunk lidand resold the remains for $500. There was enough left to do 2 sets of XJ-S parts.. (including fenders)
Hint, if you make fenders use at least one layer of kevlar in them that way when someone gets leaning on you his car absorbs the damage all that happens to yours is the paint get's scuffed..
PS paint your car black and virtually any touch up paint will match.. buy extra sets of decals Almost all of the damage done to my cars in 5 decades has been garage/trailer rashes.. but still it's nice to keep the car looking decent.. (even if it is your own fault)
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