• From: Oakland CA
  • Registered: 2010-06-16
  • Posts: 70

Re: CLONE Cars?

The 94 XJ12 is a great race car.  Except when the brand new distributor cap cracks like a champagne glass at the opera
or when one of the engine thermostats jambs closed
or when the transmission gets too hot and locks itself into second
or when the front sway bar bushings fall out on the track and causes the car to handle like a bag of lumpy ass
or when the front brakes get cooked
or that taking 800lbs off of the car actually worsened its handling

You can ask the other racers at THill.  The one thing our Jag doesn't need more of is power.  Compared to most of the other cars on the track it feels like it has infinity hp.  I would be hesitant to reflash the ECU to increase its fuel consumption as it was going through about twice as much fuel as we expected. 

I think that we masochistic glue sniffers, ...er Jaguar racers, should join forces to try and get a Jag to finish top 10.  Hell, at that point we would probably all get knighted by the Queen and that is definitely on my Bucket List.

  • From: Choctaw, Oklahoma
  • Registered: 2009-11-12
  • Posts: 2,145

Re: CLONE Cars?

Does it count if we run a non-Jag motor other than a SBC?

  • From: Oakland CA
  • Registered: 2010-06-16
  • Posts: 70

Re: CLONE Cars?

I think it would, but it would need to be something more insane than a Jag V12.  Maybe 4 two stroke Saab engines joined together or as I was discussing with Alan, a straight 6 turbo diesel.

  • OMGuar
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  • Posts: 320

Re: CLONE Cars?

jimeditorial wrote:
OMGuar wrote:
jimeditorial wrote:

Three Rochester 2GC's in a tri-power set up like a GTO ought to work...you can find the carbs on lots of GM pickups, etc. The original had 2G's at the ends but you can cut off the choke easily enough...

ON what Manifold? 
Have you ever looked a Jaguar/BMW/Mercedes? Ferrarri, etc. V12?  the manifolds all come out sideways. Now the Carters used on 1953/54 Corvettes might work if you have 4 of them, However since the collectotsrs are paying insane money for them I think it would be cheaper to buy a set of webbers! ($7750 currant complete price)

A simple welded plenum with tube runners to the flanges....or mounting flanges heli-arc'd to the stock alloy intake with the throttle body assembly removed. I'm not saying it's easy, I've done it with a twin SU Rover 3.5 intake modified to a Holley flange, and yes that's more common than Jag, but factory FI can't be easy or cheap either. I think Speedycop did this on his BMW powered car.....was it the T-bird?

Interesting thoughts, yet I've done enough carb work (and some with rochester 2 barrels in fact) That I understand just how difficult it is to get them even a little close.  However the stock FI works and is unbelievably cheap. How many do you want?  Plus it will support much more horsepower than the Rocheters ever will.  Stock air intake plates are either 2.5 inches 2.7/8ths inches or 3 inches x 2 which is up there with Top fuel sized air intakes..
The real flaw in your idea is the runner length.. The ones in the stock manifold are already way too short at 11 inches into the plenum.  I forget the formula and it's based on the camshaft primarily but something closer to 18 inches would work I suspect..  Now about 5 inches from the port you're through the hood.  add 13 inches to that plus whatever sized plenum is required plus the carburators themselves.. and the air cleaners would be taller than the top of the windshield..  Maybe you could live with that on the drag strip but I'm sure tech would fail you at a road race.
  The real work would be the correct sized plenum. It get's really big for a V12 because basically you are running two 3clyinder engines with instead of 90 degree seperation 120 degree seperation per bank. I tried to do it on my computer program called engine analizer and apparently it takes more calculation power than I can generate with my computer..
  Here's the thing though.  Poorly designed as it is the stone stock injection system is capable of supporting 600-650 horsepower before the ports run out of air etc..  (later HE injection systems are limited to 400 hp) So old and lousy is actually better!  Wierd isn't it?
  All that aside, I am far better off taking any money I can and change the transmission to something better..
  The Borg Warner cast iron case was never intended to handle this much horsepower and torque. While the later Turbo hydro will there is too much loss and inefficency in it.
Pick up a domestic manual gearbox  4-5 speed for a few hundred dollars and you already have a bell housing that will fit the V12 ahead of the Borg Warner All that would be required is to machine an adaptor plate and now you can keep that V12 operating in it's best range..
Both the stock Borg Warner and later turbo hydro will shift at 5000 RPM.. leaving the peak powr and torque on the table to be wasted..
   add slipage losses and a manual would do more than any change to the intake system.. 
There were manuals made for the engine but none came here to America. I'm sure that getting one from England would completely shatter the $500 limit..

  • OMGuar
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  • Registered: 2010-09-01
  • Posts: 320

Re: CLONE Cars?

FraidyCaptain wrote:

The 94 XJ12 is a great race car.  Except when the brand new distributor cap cracks like a champagne glass at the opera
or when one of the engine thermostats jambs closed
or when the transmission gets too hot and locks itself into second
or when the front sway bar bushings fall out on the track and causes the car to handle like a bag of lumpy ass
or when the front brakes get cooked
or that taking 800lbs off of the car actually worsened its handling

You can ask the other racers at THill.  The one thing our Jag doesn't need more of is power.  Compared to most of the other cars on the track it feels like it has infinity hp.  I would be hesitant to reflash the ECU to increase its fuel consumption as it was going through about twice as much fuel as we expected. 

I think that we masochistic glue sniffers, ...er Jaguar racers, should join forces to try and get a Jag to finish top 10.  Hell, at that point we would probably all get knighted by the Queen and that is definitely on my Bucket List.

I do know some of the aftermarket distributor caps are pretty shaky, and since Lucus themselves sell them it does call into question their quality control..  You aren't stuck with the morelli ignition system are you? that would explain it even better.. Something caused the cap to shatter, Have you had your distributor on a distributor machine?   A lot of them really need work.. The ones I've looked at 5outa 6 have problems..   Gut the thermostats.  You don't need to meet emission limits and parts left off will never fail..  Is your transmission the old Turbohydromatic or the newer 4 speed out of Germany?  I do know they are both poorly set for the engine.. The Turbo hydromatic leaves 1500 rpm on the table right where  the shift causes the engine to drop behind the curve and I don't believe they are using the newer Transmission in the British series for XJ-S's. Not  whole lot of experiance out there with that gearbox..
If you really want your engine to come alive, (and save your brakes) get the bell housing from the earlier Borg Warner transmission, and make an adapter plate to a domestic 4-5 speed gear box..
  Regarding Brakes.. they use stock ones in England in their race series. They are really serious about braking.. don't forget the British series requires absolute all out charge  Much more demanding than an endurance where something is always kept in reserve..   Good pads, Fresh racing brake fluid before every event and duct air to them..  Actually the fresh racing fluid before every race is the biggest key I've found.
  Yes taking 800 pounds off the car does make it higher and in the worst part of the chamber curve.. that's why you have to cut the coils.
Then put it on a serious diet. Remove the glass and if you want you can replace it with lexan..  Consider making Fiberglas parts rather than hauling the steel stuff around.  There are hundreds of pounds (maybe another 800) to be lost that way and if you do it yourself really cheap to do. (time consuming but cheap!) Plus the real bonus is when you smash a fender, door or whatever,  You simply remove the pop rivots holding it on and put on a new one.. If you're clever  you'll have the gel coat match the car color already so no painting will be required..
  According to Roger Bywater  changing the ECU  doesn't hurt mileage.   He talks about it on his web site.. Considering the stratified charge principle used in the later HE engine Id' be afraid of melt down! That's Why I prefer the earlier flat head engines. The earlier engines are capable of 650 Horsepower compared to the Later HE engines 400 horspowwer limit.. (Far better flow potential with the earlier engine)..
However great fuel mileage isn't ever going to be possible with the power and torque of that motor..
When they were racing the factory BMW's in The ETC (European Touring Car) series the Jag would always sit on the pole and run much faster than the BMW's  But with the extra pit stop required   It's very much a Rabbit and Turtle race which is exciting as heck for the fans..
There is one other thing you really should do..  The stock rubber bushings are shot by now..  replace them and then revalve the power steering.. it will turn it from a lumbering, hard to control  beast into something approaching a  decent car..  (oops I almost said race car!)
Hmm I'm wondering if  we should be sharing this information here on this site.. Others might realize the potential of these and then what would I do?  I'd hate to actaully have to pay for one..

  • 325c2
  • Paddock Rat
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  • Registered: 2010-01-25
  • Posts: 31

Re: CLONE Cars?

morelli ignition, yeah we are stuck with that.

The transmissions has actually been fairly solid as it is a gm 4l80e, it just needs better cooling. although I wouldn't mind a manual swap if we can get it done.

I like the idea of a reflashed ecu but I don't think it is in the budget. however is sounds like it might be more of a problem than I thought. We might have to put it on the dyno to see what it is doing and go from there.

The car will be lower lighter and better cooled for the next race. we are thinking about cutting the springs but then we end up with a lowered car that is still fairly soft. It is however free so it is first on the list of things to try. I think that our biggest problem handling wise was the shocks, we probably wont find the perfect set of shocks but some sort or damping would probably help. After that add some swaybars off of a truck and we might almost have a racecar.

  • OMGuar
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  • Registered: 2010-09-01
  • Posts: 320

Re: CLONE Cars?

EriktheAwful wrote:

Does it count if we run a non-Jag motor other than a SBC?

Why would you ever do that?
You realize the SBC has to be pretty snarfy to make the horsepower and torque a stock V12 will don't you?  Yeh the little V12 (326 cubic inches)  will put out more torque than a crate Big block!  ( Little tiny 2 3/4 stroke plus a  3 1/2 inch bore makes more toque than a 454? )  I know you want to accuse me of spreading an untruth.  it's true! check it out!
Learning the stuff about  Jaguars is just the same as learning about Chevies. (well except you have to be able to count to 12 instead of 8)  (big silly grin here, please)  In fact you don't even use metric wrenches on them..  1/2, 9/16ths, 5/8ths,3/4, etc..
The transmission is  amde in America.  A Turbo hydromatic 400 or the earlier ones used the Borg Warner.
But it's massively more beefy than the one in a chevy..
It's the one they used in tow trucks and garbage trucks  HD 1 ton or bigger!  (because of all the torque) 
The really cool thing is if you ever see the block upside down and emptied.
You'd swear it just came off a top Fuel motor except for those 4 extra cylinders..  All aluminum and hell built for stout! OH and if you like power?  you can bore and stroke that engine over 500 cubic inches..  Think what that would do for torque.
  The crank and Rods are Fordgings, not sintered metal like  Chevy uses..
  If somehow you manage to wear out the engine after a few hundred thousand miles
  You can completely rebuild the engine back to exact factory specs. right in your garage. No boring required.. slide the old sleeve out and slide a new one in.. stock bore!
The Oil pump is so advanced that just now is Corvette using something similar  on their dry sumped motors Like the Z06 and ZR1. Jaguar had it 39 years earlier!
One final point, In the trade Chevy engine swaps into Jaguars are known as lumps.

33 Reply by OMGuar (edited by OMGuar 2010-09-02 12:34 PM)

  • OMGuar
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  • Posts: 320

Re: CLONE Cars?

325c2 wrote:

morelli ignition, yeah we are stuck with that.

The transmissions has actually been fairly solid as it is a gm 4l80e, it just needs better cooling. although I wouldn't mind a manual swap if we can get it done.

I like the idea of a reflashed ecu but I don't think it is in the budget. however is sounds like it might be more of a problem than I thought. We might have to put it on the dyno to see what it is doing and go from there.

The car will be lower lighter and better cooled for the next race. we are thinking about cutting the springs but then we end up with a lowered car that is still fairly soft. It is however free so it is first on the list of things to try. I think that our biggest problem handling wise was the shocks, we probably wont find the perfect set of shocks but some sort or damping would probably help. After that add some swaybars off of a truck and we might almost have a racecar.

OK the overdrive version of the turbo 400. that transission has a great reputation allright. lots of cars and trucks use it and it's pretty decent..
You're right it will over heat.. don't count on the stock cooler to do much  the cheap way to fix it is take the A/C unit off from under the dash  Cut the ends off and weld on ends to fit the Trans hoses.  It not only looks cool but it will drop temps like you wouldn't believe..  I have one of those oil coolers on my "D" type and it's been there cooling that oil since about 1979. Oil temps rarely get even warm unless I tape it..
  Cutting coils stiffens the springs.. Try it! Honest it works.. I could explain it to you but it's easier for you to prove it yourself! Oh and it does lower the car as well. 
  You would only neeed to put the Jag on a chassis dyno if  you're going to try to redo the E prom chip yourself..   Probably easier and cheaper to simply use Roger Bywaters chip. There are aftermarket chips out there for your car for I think it's $59.00 each..
If you had the older ecu's they sold a variable potentiaometer that allowed you to add or subtract fuel based on whatever you felt best that day.. There are enough of those here now That I've got a couple..
It's pretty easy to crank up the fuel pressure and retrim the bleed off valve yourself and not need to use anything other than stock parts.
  Combined with the earlier systems variable pot..  You can be just as accurite as is required..  (buy yourself a great air density meter and you can tune it spot on based on the air density when you went out!
You can't do that with a reflashed E prom chip..
What about your exhaust?   Please describe it to me. (from the Iron manifold to the ends of the pipes).  I suspect you're leaving a whole lot of power on the table..
Junk yards with a lot of trucks is where you should be looking for sway bars..  Ideally you need a 1& 1/4 inch bar. If you are clever  and there is a spring shop nearby  I wouldn't Buy one off a truck.. I'd get the right diameter and wall thickness, bend it into shape and then bring it into the spring shop to be heat treated back to spring steel.
   Instead of bolted on ends I'd make a simple slider..  That way you can tune the handling.. I don't know what they get now BUt I paid $25. for my sway bars heat treated.. 
You do have to replace the bushings..   The stock ones seldom lasted 5 years before they began to have problems  16 ears old?  Treat them like a babies dirty diapers!
  Shocks,
More money has been wasted chasing down the perfect set of shocks.. .  Do you know what you're looking for?  Remember the art of shock selection has to consider the countless variables..  There is a computer program on handling out there that will help you make sense of the multiple options you can use..  (well unless you can afford the aluminum double adjustable coil overs from Koni.) Back in the early 80's I paid $1800 for 6 of them. I don't even want to think of what they'd cosat today!
Manua; swap.
  It can be so easy! IF you have a junk block and a junk tranmission and access to a lathe (wood lathe is just fine!)  I'll bet I could talk you through the process.