Rob Wade

Haven't posted in quite a while (life changes course when you least expect it sometimes!) but I own an 89 Jaguar XJS convertible that I trasplanted a TPI/700R4 combo into about 4 years ago. The motor is a new GM L31 shortblock with TFS 175 cc heads, stock L98 camshaft (its a cruiser first and foremost and economy was an issue) with 1.6 rr's. Its got a big mouth intake, edelbrock hiflo runners and a modified plenum. 52mm tb and a VERY mild tune that easily flies through my byannual etest. Shorty headers, magnaflow spun cat cat's and a custom flowmaster with two magnaflow mufflers out back. Yes its not loud.....and I like it that way. The trans is a well built 700R with a 2800 stall lock-up converter. In the rear the jag rear diff (dana44) has bean modified to accept a dana 44 3.23 gear which is pretty close to what the motor and trans had from the factory. The car weigh's in at a hefty 4010lbs wih me in it! Can you say Luxobarge! Anyway, I finally got the opportunity to get the car to the track for a local street car race. Running the car 100% as I drive it on the street with 91 octane fuel, I got the pig to run a best of 13.89 @ 97 MPH with a consistant 60ft of 1.92 on a NON drag radial, Hankook275/40/17 radial. The car still retains a legit 24-25 mpg on the hiway and has great drivability. Just thought I'd send a few pics of my TPI motor at work!

wicked-irocz

Very nice. I think you did a terrific job on that swap.

Damon

Very clean install. You don't see many guys modifying a Jag for Performance!

What's the link hanging out in the breeze at the back?

RMK

Nice job and good numbers for that car.

What engine did the Jag have before the swap?

Rob Wade

Thanks for the props guys. It started life as a V12 car. The link hanging out the back is a modification I made to the lower tie plate on the rear diff/suspension. These cars have the entire rear suspension bolted into a steel "cage" which is then all rubber mounted in the car. Under hard acceleration the cage can flex and change the pinion angle causing lots of wheel hop, broken mounts etc. This link hanging out the rear started out life as a new prototype rear lower control arm for the 2010 Ford Explorer. I grafted a portion of it to the stock tie plate and then fab'd a mount from .125 stainless plate which was grafted into the truck of the car. This will (does) help limit cage flex and mount failure. Here's some pics.

RMK

Would have loved to see numbers for the stock V12 and again with some simple mods to the V12.

Good project.

Rob Wade

The trouble with the twelves is that mods are very expensive and the motors are really difficult to work with. They also have some inherent flaws like head gasket problems, poor quality castings/tolerances etc. Hence the reason Jag/sbc conversions are so popular. They (V12) actually weigh about 150 lbs more than the sbc, make the same horsepower and considerably less torque. To top it all off, they are harder on fuel so its a win/win/win situation going with the TPI motor. Especially with the gobs of torque needed to move these boats! The car runs really strong to the '990 and then kind of noses over as the motor doesn't make much over 5500rpm......but I knew that would happen, and I'm ok with it. I would like to run a V12 XJS "heads up" to see how they would fair against each other. Problem is that there's only 4 other XJS's around here, and they're all owned by old fodgers who probably don't drive them past 30 mph!!

gearhead0384

iTrader: (7)

I like it and you did a really clean job! Nothing betting than going fast in style. Now you have to start moding it.

RMK

Agreed, it is a very clean job. Did you paint the plennum & runners yourself? What do you think of the Edelbrock runners?

86camaroZ

now he has to mod it?

that things perfect how it is man, congrats!

TigerVette

Great looking Jag.

Bet you surprised quite a few with the hard launch.

Thumbs up on the solid black engine

Rob Wade

Thanks guys. The entire intake/runners and plenum, plus all of the CIA and rad support are all black crinkle powder coating. The car is not a racecar so further engine mods are not in the cards. The engine package was based upon torque to get the heavy barge moving and still retain decent fuel economy. My choice on the edelbrock runners was simple. I like the look of having the fins polished to contrast the black. The edelbrocks are the only ones like that. I clamped them up in a mill at work and removed the edelbrock logo and then just taped off the fins on the runners and plenum before powder coating them. I almost wish I had a set of welds or something to stick on the car. I have a feeling if I hadn't had those heavy 17" jag rims on it, there just MIGHT have been a little daylight under those front tires!