Hey all,

I was wondering if anyone has retrofitted coilovers? given the amount of space from the bottom spring cup to the thingy-mabob that sticks down from the top spring seat, it seems impossible (stud-style M2 or GM coilovers would be the type but they are way too long). The shock mount (lower) couldn't handle the weight of the car even if a new upper mount was fabricated. Just wondering if anyone has ever done it, and if so, i'd love to see pictures

best

drew

 

pictures say a thousand words!!

i always try to add some pix about the thread subject!
the rears are coil overs, 4 of them!

 

I don’t have any pictures the more I study the space and what’s available it doesn’t look possible

 

If you are talking about the front suspension, people have, and there is even a kit available. BUT it requires very extensive welding and fabrication and also restricts suspension travel. There was a thread about it on here somewhere.
https://www.jaguarforums.com/forum/x...lovers-224510/
Found the kit maker:
https://xcessivemanufacturing.com/ja...nsion-774.html

 

Bummer. I’m totally comfortable with the fabrication but I wouldn’t want to sacrifice travel as ride is what’s most important

worth a shot
thanks

 

I could be wrong of course, so you could talk to them and ask. I do believe though, that it is inevitable that ride quality will suffer with a higher-geared suspension setup.

 

Drew, what are you trying to accomplish?

The XJS suspension responds well to some easy mods and tweaks that have minimal impact on ride quality

Cheers
DD

 

Let me second that. The stock system has pretty decent geometry. For racing I cut two coils out of each spring which lowers the car by 1&1/2 inches and stiffens the spring rate. (The car will gain about 1-1&1/2 inches of ground clearance because you take so much weight out ). Go to a 1 inch tubular bar of 4130 steel heat treated by my local spring shop in the front. ( Speedway Engineering sells one with splined ends and aluminum arms for only a little more). The stock rear sway bar works pretty well, just mount it in aluminum instead of rubber. I eliminate the rubber isolators front and rear Just bolt them straight onto the frame. Which drops the car another inch lower. Total you’ll wind up about 1&1/2 - 2 inches lower than stock. Don’t get greedy and try to go lower. You’ll start to get in the ugly part of the camber curve.
Assuming the shocks aren’t leaking I drill a small hole to drain the oil from each and depending on how smooth the track I’m going to race on is, I fill with motorcycle shock oil. A really smooth track With big radius corners I’ll go all the way to 50 weight. But a really rough track calls for 20 or even 10 weight. I use a self tapping screw coated with silicone to hold the fluid.
I’m lucky, two of my favorite tracks call for the same oil. The one that I use 20 weight on I don’t like because it doesn’t have any really high speed parts on it which is the Jaguar’s strength.
I have raced with the 50 weight on the short bumpy track and it costs me about 1/2 second a lap. But the real cost is I don’t feel as planted under really heavy braking. So I can’t be as aggressive.

I’ve raced with Double adjustable Koni coil overs, There is some speed to be gained but it takes a lot of laps to dial the shocks in properly.. You need clear lines marked on the track and someone with two stop watches starts when your front passes the corner enter line and stops when you pass the exit line. Yes, you still need another person keeping track of your total over all lap times. That person announces lap times at start finish and how much faster or slower you are. You need to respond I was blocked for a bit at the end of the third straight. Or I got a good pull down the front straight. At that point as a driver you have to get consistent lap after lap. Once you are consistent After about 5 laps in a row, turning the same corner time to .001 of a second you can go into the pits and make really big changes. Don’t try one or two clicks. Go from full Jounce to softest jounce. Then try for 5 more exactly consistent laps.
At that point go back and return jounce to full and adjust rebound to the opposite.
You have to be really consistent. Drive at, at least 95% of your full race speed. Plus you need to be honest with everyone. If you tried to squeeze a little more or took it a fraction easier you have to announce it.
Have the person doing the overall lap times write down your comments.

Looking at the comments and lap times try each setting Its’s like when you go for an eye exam is this better or worse, only really really slow.




This is hard, boring, and expensive stuff.
it pays off in wins though

 

Doug, lower but extremely soft like a 70s Buick. Strange but it’s got to be doable. The 466lb/inch coils are just too firm for what I’m doing

mguar that is incredible! I’ve been around cars forever and even built in with many parts of my own design and fabrication but I know ZERO about racing so that was interesting

shocks. Never knew you can do that! So you achieved stiffer which is better to racing of course. Do you think there is an oil they would give jag shocks and even softer feel?

Funny you brought up sway bars. That’s another issue for me. If someone was to run the front sway bar upside down (that’s how it fits best on my project) would it’s function be the same? I had purposed to search for a new one from a donor vehicle that was straighter.... like more of a simple shape rather than all twisty to fit around frame and suspension components


thanks this is really educational

 

This is very dated info. Stop watches? They have Cell phone apps you can run... they tell you in real time you speed, G force and how much faster or slower you were in a particular sector compared to your last few laps. You can adjust and improve in real time and your spotter can also coach and watch the feed and see the data. The cell phone apps are amazing, they take video and can even integrate with the OBD2 data and get throttle, brake, RPM, and temp data. There are full in-car systems too.

I use Harry's Lap timer. It's 9$
https://www.gps-laptimer.de/
https://racechrono.com/

I dont think anyone serious is still drilling holes in their shocks and changing the oil.

 

That’s cool!

as for the shock thing, I like his idea. old approaches are sometimes best. I won’t be racing like you guys, just throwing on the tunes and enjoying a cruise

you guys have a SWEET hobby though. Very cool

 

Yes there are a lot of things to make you faster. So I don’t doubt you, but you’ll need to explain how to use a cell phone while you’re racing. I pretty sure that’s distracted driving of the worst sort.
As for drilling shocks, have you heard of LeMons racing or Champ car racing? Basically it’s really cheap racing. Honest wheel to wheel racing. Cheap cars with very few ( if any) performance pieces. You’re required to have proper safety equipment so you don’t get hurt. And then you race, Endurance races. Up to 24 hours of on track time. But at least 7-8 hours.

I’m sure the faster guys are onto changing shock oil. Its’s been done since I was a kid. The really fast guys know which shocks are biased towards Jounce and which are biased towards rebound. If you really know what you’re doing you can make almost anything fit and work on any car.
Show up with a set of double adjustable shocks and you’ll get assigned so many penalty laps finishing in the top 40 will be hard. As for in car systems? Forget it!
I like the idea of taking a $500 car and winning races with it. Sure if you have a couple hundred Thousand you can buy a faster car but then it’s your check book beating somebody else’s check book.

 

So mguar what fluid - even jack or air tool - would a guy use if he wants a very soft 70s Oldsmobile/Cadillac ride

 

Thinner fluid would give that sort of ride. try 10 weight motorcycle shock oil.

 

A sway bar is simply a sideways torsion bar. Upside dowN, right side up, as long as it doesn’t hit the chassis or suspension it doesn’t care.
So yes it will work.

As far as stiffer, it’s not always true that stiffer equals faster, often but not always. Frequently stiffer is compensation for a problem. Such as poor suspension geometry, flexible chassis, bad roll centers. Etc etc etc.

Our Jaguars have pretty great suspensions under them. But they can be improved if racing is your goal. The hard part is to not to overdo it. When I built a race car I always put optional mounts in. Usually my original settings would be pretty close, but the ability to adjust to different tracks or conditions is what gave me that little edge.

You’d be amazed at how many people spend way too much money of some go fast do-dad or gadget. And neglect the hard work of getting the most out of what you have.

If you want softer springs use the coils from a 6 cylinder instead of the V12.

 

You can achieve the same thing with the front springs as adjustable coil overs do at the rear. The trick is you make an adjustable plate to go under the front spring. Then you can pull into the pits, reach underneath with a wrench and adjust the spring.
careful though because doing so will preload the sway bar unless you adjust both springs the same amount.
Now a preloaded swaybar May help or hurt. It depends on what the car is doing. It’s relatively easy on a circle track car but on a road race car the answer is more complex. Depending on what you did the preload May hurt you one direction but help you the other. If the track’s critical corners coincide with the help, you gain. otherwise not.
Be careful though. It’s easy to get messed up. I like to start square without any preload. And as a last resort try preload.
You may be different.

 

Cool! Pardon my lack of ingenuity... but where do I drill? The top?

 

Missed the other two replies sorry

tried to get xj6 coils from the junk yard yesterday but the car was sitting on welded steel Rim stands On the lower control arm plates

i also plan to put 3/4 inch of spaces between my lower arm and a plates which I’m told lowers the car about 1.5. Maybe that will soften it up a bit too because the spring will start less loaded?

ive considered 2500lb airbags instead of coils but don’t think I want to deal with the hassle

Cool on the sway bar!

man thanks

 

You need the coils from an aluminum engine not the early cast iron one. The cast Iron block six (designed during WW2 brought out to 4.2 ). That is actually 30 pounds heavier than our V12. You’ll want the AJ6 alI Aluminum one.Sorry I wasn’t clear

Working with those springs has killed and badly injured people in the past. So please use the proper equipment. I may rather cavalier about it but that’s from many decades of experience. Please don’t follow my poor examples.

 

In the reservoir. As far away from the moving shaft Sliding through the seals as possible. I drill really slowly with the drill bit heavily greased up. In a way so once through into the reservoir the existing oil will flush shavings out. That usually means I’m drilling from the bottom up. Yup it’s awkward as heck. Too often I get a face full of oil or worse.