Hello everyone Im picking up an 1988 xjs v12 not sure of the size yet .I can not find performance cranks /connecting rods/ pistons rings etc anywhere!? Im going for a procharger build eventually. cars been sitting but is immaculate no rust or rot surprisingly once its home itll be gine through but not much is beeded.any help will be highly appreciated

 

The market for performance parts on these engines is fairly small simply because there just wasn't enough of them made to make it worthwhile for the aftermarket manufacturers. However, you CAN buy them but at a premium price.

I would suggest you scroll down and read Calvin's thread titled Building 6.8. He's already researched many of the questions you'll be asking.

 

Thank you kindly!Price is not an issue Im a service tech so at least Ill save some $$ on the build.

 

alright everyone relax Im here.
what are the plans for this motor? 400hp 500hp 600hp 6l 6.5l 7.0l? lemme know and I can help out

 

Do you guys mind if I jump in and ask a few performance questions about getting better performance out of my 87 xjs? it's going to be a 24 hour racer. it seems that we might have some of the same questions/issues. Thanks, Kev

 

go for it!

 

I have an 87 XJS that we are setting as a race car for the 24 Hour Lemons competition. I ran with a BMW team in the past but never have I seen a Jag in the races. Well... it's time. I several jags but this is the one I'm dedicating for the track. I'm trying to get as much out of the 5.3 as I can without opening her up. Any tips mechanical, electrical, cooling etc would be greatly appreciated. I have stripped everything out from under the hood that I can that I don't need. Two radiators and two trans coolers. The fuel cooler is no longer there. I'm looking for new wheels too. Anybody know what the bolt pattern is so I can get some used or aftermarket wheels? 18" sound about right? It weighs about 2,600 lbs right now with the glass in. That will be removed soon, just before the cage goes in. Anybody have a used cage for an 87 XJS? I'm trying to have this completed by October. Thanks in advance. Kev

 

the 5.3 you'll just need a good tune and a good intake/exhaust that'll make it over 300hp. some people have been taking camaro cages (second gen) and.modifying them to fit. idk what your welding ability is. as for the wheels, im running 245/45r17 up front and 275/40 r17 in the back. bmw 3 series wheels fit wirh the hub centers opened up. and a spacer up front.

 

I have cut out the cats and am using an over-sized exhaust that runs under the door similar to a Cobra header system. Got rid of all of that piping and weight. I 45'd the ends to extend out from the rocker panel in front of the rear tires. The exhaust does not exit on the tire surface but just beyond it. The flow is great and I added a free-flow muffler to each side. That seems to have made the decibel level tolerable and keeps some of the heat off the rear brakes too. those 12's straight piped is just too much for a 24 hour race. Should I machine the intake to enlarge the opening? What do I do for a butterfly at that point? Machine a new larger one? The fresh-air intakes protrude through the hood under scoops with mesh screens. That Camaro cage is a great idea. Never would have thought of that. Any idea what the actual bolt pattern spec is for those wheels? That way I can do a much more efficient search for wheels. 17in? That sounds good and easy to find too. Thanks so much! Kev

 

5 on 4.75"


Cheers
DD

 

Thanks Doug! Kev

 

the guy I have been getting advice swears by the quad throttles, so id do a.google search on how to.build that setup.

 

Quad throttle? never heard of it.

 

Looks pretty involved to make a few of them but I think my shop can do it. Once I get the template down I can punch them out at a clip. I wonder if there is a market for them. Anybody make headers for these? Not sure how much of a performance increase I'll see using headers but it will save some weight. Anybody ever try them? Thanks for the information. Kev

 

Actually, there is at least one XJS running in the LeMons Series. Check this link: Cars - Magnus Racing Club

 

That's great! We have yet to see one back east. I can imagine we'll have the same trans and head gasket problems they did. We are hoping that the doubled cooling for the trans and motor will keep us off the hook. Some interesting ideas in there. Thanks, Kev

 

Anybody know if I can tow a 91 XJ-S with the rear wheels in contact with the road? I want to use a car dolly to move a new purchase but not sure if i can get away with putting the front wheels on the dolly. Will it boil the transmission if the rear wheels are in road contact?

 

I use a tow dolly all yhe time it works fine

 

I log off for awhile and the thread blows up lol. Calvin im looking for a 1200 bottom end and 850 hp . Always build it stronger than needed it lasts longer and handles the power an abuse better. I was calm in my last post I apoligize if it came off wrong. that being said where do I start?! Ill build the suspension and braking system first but ,Id like too stash away parts bit by bi till I have everything for the motor. then Ill build it up. im thinking of an oil cooler or coolers with an air scoop pushing air too them? Plus a bigger radiator an fans.

 

And where can I get a set of chrome lip rims with dark blue center?