Hi, I'm scouting the used car market and have my eyes on the F-Type AWD. The problem however is that I live in an area with roads of varying state of decay, steep driveways and during the winter - snow requiring a bit higher suspension. I currently drive an Alfa 159 and it's really low, barely enough for most uses and I commonly scrape the front bumper or oil pan on various occasions. Now, the Jag is quite a bit of a different car and such low ground clearance would for sure lead to some visual or structural damage in my area. Therefore, on the verge of disqualifying this amazing car, I ask myself this: can the suspension be raised and is it a viable strategy?
I've seen people lowering their F-Types but noone has raised it so far (except for one rally conversion). How would such a mod impact the car? I suppose 25mm would be absolutely enough, maybe even 10mm would give some absolutely needed clearance. Is it a good idea or would it ruin the car?
I've seen a company producing spacers for Jaguars (including F-type) that go on springs and raise the ride height by either 12 or 24mm. Would this be a good idea? Or maybe different springs?

Thanks in advance!

Vedemin

 

I'd just get rid of the sacrificial front aid damn that's below the nice painted one. It sticks down an inch or two lower and is the first thing to hit.

 

The answer to "Is it possible?" is "Anything's possible with enough money." "Viable," "Worth it," or "A good idea?" Probably not. Some quick info on suspension to help explain - when the vehicle is at rest, its weight compresses the suspension to the "sag point," which might be something like 10% or 20% or 30% depending on the vehicle. The number doesn't really matter.. what does matter is that the car, at rest, is sitting X% into the shock absorber's travel which allows the suspension to work in both directions - it can compress when it hits a bump, and it can rebound when it hits a hole.

Lowering suspension is relatively easy - put a new spring in that moves the resting point further into the shock absorber's travel, and now you're sitting at let's say 30% into the shock's travel at rest. This means you still have movement in both directions... you have more room for rebound which you probably won't use, and less room for compression which is handled by making the spring a bit harder so the car doesn't hit the bump stop. You can usually get away lowering a car an inch or two on the stock shocks, because you've just moved the sag point closer to the middle of the shock's travel and you have plenty of room for both compression and rebound.

Raising is much more difficult as you rapidly run out of rebound space on the stock shock absorbers... let's say you have a car that has a total of 5 inches of travel and its sag point is 20%, that means it has 1" of rebound travel from sag and 4" of compression travel from sag. If you raise this suspension by 1" you now have 5" of compression travel and zero rebound travel, meaning the wheel can't rebound into a depression and you will lose contact with the road every time it drops away.

This is a very long way of saying that if you want to raise a car, you can't just slap a new set of springs on and call it a day.... you almost always have to install longer shock absorbers to give the system enough rebound travel to operate properly.

 

I fabricated some 1/2" spacers to go under the spring seats and have them on a set of shocks I got, along with some VAP lowering springs. I haven't installed them yet (it's a pain without a lift) but did that because I wanted the higher spring rate but thought the reported 7/8" lowering would be too much.

The lower spring seats are plastic, so I made my extra spacers out of impact-resistant HDPE sheet I sourced from McMaster-Carr. It'll probably be spring (at least) before I put them on.

 

AIR BAGS he he

 

Spacers might work in your situation as you're still lowering it 3/8" from stock (weird way to do it when VAP will do custom ride heights, but it's your car *shrug*). If raising above the stock ride height, the issues above will present themselves regardless of how it's done.

Still requires longer shocks unless the airbag is between the top of the shock and the body.

 

Brainwave - the way to do it without running into the rebound issue is to put a spacer (could be an airbag I guess) between either the top of the shock and the body, or the bottom of the shock and the hub carrier. This would change the body's position (or the wheel's position) relative to the shock without changing the spring length, and would raise the car but leave the shock in the same resting position.

Whether this is a good idea or not is up for debate! The results are likely to be unpredictable (possibly dangerous) and we're starting to talk about using custom parts to do something that probably hasn't been done before so we might be creeping into "Not worth it" territory.

 

Thank you everybody for all the replies! So with longer shock absorbers it should be possible to do correctly? What about the center of gravity and the like? And what would be the general cost I would be looking at if I wanted longer shocks that would handle the stress?

 

Well stated. Had Jeeps and Land Rovers....this is absolutely a true statement. Leave it stock and just either deal with it or realize it is NOT the car for where you live.

That being said, my car is at stock height and I've been fine in car parks. Go figure. And I think they nailed it...it looks good stock.

 

Yes, correctly lifting a vehicle almost always involves longer shocks. I doubt there's a product that just bolts on so I think the easiest way would just be to have a custom setup made with ride height adjustment. If you google "custom coilovers price *your country*" you'll probably find some sites that will help you get started... I did that for Australia and I found a place that will do a set for an XJ for au$2250 (about $1700us I think) and Jag Madness shows an adjustable KW coilover kit for the F-Type at $3650 (USD I think) so that gives you a range to start working with. I'd consider adjustable ride height mandatory for your purposes.. it'll let you fine tune it, maybe raise it in winter if you get snow and drop it back down in summer, or maybe you raise it all the way up then lower it 10mm a month until you start hitting the road and now you know that's as low as you can go. Having the adjustment means you can find the exact spot you want it rather than just jacking it up an inch and hoping it doesn't drive like a boat 😂

There might be other issues with the install as well - for example a common one is finding other moving parts in the system that are already at the end of their travel, or very close to it.. another is that wheel alignment becomes difficult because angles change as the suspension moves through its travel and the rate of change is often higher at the ends. You can check this by jacking the car up to exactly the ride height you want and, as you're raising it, watching each wheel to make sure the suspension doesn't bind, then checking your angles to make sure the alignment is within spec or can be brought back to spec easily. If you're having a steering/suspension shop do the work, they should inspect the car before ordering to check all this and take some measurements before you order your kit... use this time to get to know them and decide on whether to trust them with the install.

Actually try calling around all the suspension shops until you find one that's raised sports cars before.... If you live in an area with a large population and all of your roads are horrible, chances are some of your local shops have already done this on similar cars.

 

100% agree. They do make these:

 

When I got the springs that was not an option (2019 Black Friday Sale). I recently acquired a set of 11K mile shocks from a 400 Sport that was being salvaged, so put the spring on them. They were not "fully captive," i.e. there was movement of the spring on the shock assembly but off the car, so 1/2" was also enough to keep thing in place even at full extension. There is still zero preload off the car on the rears but at least the spring can't move around.

Weird, perhaps, but my driveway is such that the outside wheel unweights almost completely entering and exiting the street. We'll see how it works when I get around to installing them. The spacer between the spring and perch will have a different effect than a spacer between the top mount and the body. I'll be changing ride height indirectly by spring preload, not directly by mounting.

 

If you only wanted about 10mm all round you would potentially get it from a slightly larger tyre. Anecdote - I recently changed my rears from 305/25/r21 to 305/30/r21, the fronts stayed the same, anyway I was told it would be about an extra 12mm of sidewall all the way around so I guess that means an extra cm or so ride height, about an inch overall wheel and tyre height. I am convinced it has made by front slightly lower (by the tipping effect of the rear being higher, is it too simplistic to say that will result in the front being about 1cm lower than it had been?) and now I am much more prone to scraping the plastic guard under the front bumper. But doing the same at the front would potentially interfere with the speedo slightly, I'm assuming it would show a lower speed with the bigger circumference. Apparently you can recalibrate the speedo, never done it.

 

Does changing the wall hieght of the tire screw up the speedometer.

 

Probably yes at the front wheels (didnt on the rears) but it looks to be an easy fix to recalibrate on some cars, not sure about the Jags

 

F-Type speedos are almost always some 6%-10% optimistic, ie they read higher than the true speed.
I find the faster you are going the bigger the error, eg 6% optimistic at low speeds up to 10% optimistic at high speeds.
Fitting "taller" tyres i.e. larger rolling diameter helps to correct this over-read so your speedo is more accurate.

 

Vehicle regs demand that behaviour - speedos must never indicate less than true speed and in the UK may overread by up to 10% + 3mph, I believe. So when you go through a speed trap in excess of the limit, your speedo should have shown you were a lot over the limit!

 

Are you sure? That doesn't really make sense, speedos usually just use the circumference of the wheel multiplied by the revolutions so if it's 10% out it should be 10% out across the entire range. The margin will differ, i.e. 10% fast will read 66km/h when you're doing 60 and 110km/h when you're doing 100, are you sure that's not what you're thinking of?

 

It is, but you're on the right track. If the pivot point (the front wheel, in this case) is exactly halfway between the two spots you're measuring then yes 10mm at one end equals 10mm at the other, but the front wheel is much closer to the front lip than the rear axle so the ratio will be different. I imagine 10mm at the rear axle is closer to something like 2.5mm at the front lip, but still may well be the difference between scraping and not scraping.