Suspension/handling as a whole

[SteveR]

What do I mean by that title? Let me try to explain.

 

I'm hoping to perform a gradual, but as 'complete' as I can afford, refresh on my Supra. It's one of the latest made cars in the club but that's no excuse not to acknowledge when components are getting on a bit and need replacing, but whilst I'm at it I can take a step back and upgrade other things along the way.

 

I'm currently thinking about the car's handling and suspension. It's great as it is but I think it could be better still. I would be interested in hearing people's experiences and expert opinion on the following:

 

- strut braces F/R

- stiff/solid engine mounts

- poly bushes (wishbone mountings, diff, etc) that are close to stock stiffness and compliance

- suspension choices at say, £1k, £2.5k, £5k cost to buy

- stiffer/adjustable anti-roll bars F/R

- roll cages and the influence these have over the above decisions (could this potentially duplicate the changes F/R strut brace(s) might bring, for example?)

- anything else that should be considered, when looking at the 'suspension/handling as a whole'

 

I want the car to have a trackday focus but it's also used a lot on the road so I don't want to compromise everything: the car is used on the road so I need to be able to live with it there. If the standard supra were thought of as 100% road 0% track, a time attack car 0% road and 100% track, I guess I want to be somewhere 50%/50%.

 

For info, the spec for my Supra on these items is as follows:

- no strut brace, front nor rear

- stock bushes all round

- TEIN suspension all round with EDFC which I do adjust a lot depending on conditions and is an option I'm worried about losing if I went for 'better' suspension.

- no roll cage

- it also had a full geometry setup to my requirements.

 

The car is on, and will remain on, the GS300/TTE/Aristo 18" wheels: 8" front, 10" rear.

 

Thanks in advance to you expert types.

[SteveR]

Here are some photos of my Supra in action at the last club track day I ran (Llandow 2009), in case they help at all.

 

Entering the square section (instead of going down the oh-sh-t lane)

 

The curve between the square bit and the back straight:

 

Entering the back straight

 

At the sharpest bend on the track - half way round the square bit:

 

 

Looking at the other photos, there aren't many Supras on the trackdays that roll less than mine, most roll a lot more.

 

e.g.

 

 

[gavin.starr]

Not as much roll as that scoob in the last pic, It looks as if its going to cock its back leg.

 

With regards to handling Im sure Chris will be along soon to give you some information.

[SteveR]

Not as much roll as that scoob in the last pic, It looks as if its going to cock its back leg.

Yeah he did manage to get onto 3 wheels a few times.

[Scooter]

Trackday/R888 type tyres?

[bignum]

Ive always thought your car handled pretty well steve with acceptable roll for a road/track supra, how many miles has it done now? i doubt the bushes will be worn if at all, i`d just replace the arms that are seized and get the geo setup again, oh a cage wouldn`t hurt depends if you use your back seats.

[Nic]

For the best results I'd fit brand new OEM suspension components rather than poly bushes.

[j_jza80]

As Nic said, I've heard varying stories when it comes to suspension bushes, but stock always seem to work best. Unfortunately that's also the most expensive route, a full set of facelift wishbones and links are very expensive!

 

I'd also avoid solid engine mounts if the car is being used on the road AT ALL. They're much too noisey and the vibration is very irritating.

 

I would look into getting a TRD diff, they make a huge improvement in tight bends.

Edited May 28, 2012 by j_jza80 (see edit history)

[SteveR]

Trackday/R888 type tyres?

I have 2 sets of the Lexus rims, one set will keep road tyres on (currently P Zero Rosso fronts, Eagle GS3 rears), the other set will have 888s all round.

 

Ive always thought your car handled pretty well steve with acceptable roll for a road/track supra, how many miles has it done now? i doubt the bushes will be worn if at all, i`d just replace the arms that are seized and get the geo setup again, oh a cage wouldn`t hurt depends if you use your back seats.

That means a lot, especially coming from you Si, thanks

I need to get it up on jacks and have a proper good look at everything underneath; if the bushes (except that annoying seized one on the d-side rear adjuster) are good then that would be great! I've not driven it for 2 years so the mileage is still ~80k.

I quite like JamieP's cage; semi road, semi track, by the looks of it. I can't remember if it requires a rear seat delete but I want to keep mine. Ideally the cage would fit around everything but I know 2 kinks in the front supports means you might as well not bother, so I'm willing to do as Jamie has done and make carefully designed holes in the dash to accommodate that. Ultimately I want to vMax it one day, and I don't think I could feel fully ok about doing that without some serious safety gear adding beforehand. I've seen tha damage even relatively low speed accidents can cause, I can't imagine the Supra - or any standard car for that matter - would hold up well if things went wrong at >200mph.

 

For the best results I'd fit brand new OEM suspension components rather than poly bushes.

I've heard that a few times now, too many times to ignore. It's just so dammed expensive. Why isn't there a way of getting rubber bushes without forking out for ars etc as well? It makes no sense, binning otherwise perfectly serviceable suspension components. Don't get m wrong/ I won't compromise (it will just take longer for me to save up and refresh the car), I just think it's crazy that you can't get rubber bushes from somewhere.

As Nic said, I've heard varying stories when it comes to suspension bushes, but stock always seem to work best. Unfortunately that's also the most expensive route, a full set of facelift wishbones and links are very expensive!

 

I'd also avoid solid engine mounts if the car is being used on the road AT ALL. They're much too noisey and the vibration is very irritating.

 

I would look into getting a TRD diff, they make a huge improvement in tight bends.

Thanks for the tips especiallu the engine mounts and diff. What is different about the TRD diff? I'm not familiar with it. I know that TRD anything is generally considered an 'upgrade' but the rad cap isn't. I like to know what's diffferent and then make a choice. For the record, TRD fuel filler caps add 1bhp. My old car was definitely faster with it.

[SteveR]

I wonder if I could get magneride active shocks. That would be awesome.

[sdistc]

For what it's worth, the combination of R888s (295x35 19) and TRD differential was amazing when *ahem* "testing" the new Syvecs setup with Ryan last night - not a single instance of wheelspin and sideslip despite putting down 29 psi on a 71mm! However, many have noted that the TRD diff is designed more for drag-racing than road-racing.

[Nodalmighty]

I'll be looking at getting a old set of yellow billies as I can get them rebuilt and valved to suit. Then select the correct bump stops, springs and bushes (possibly Rose Joint the arms) and get the biggest set of roll bars made that physically fit and enjoy. I hate spine crushingly hard suspension especially then it's not needed for road / track day use.

 

Lyndon.

[SteveR]

For what it's worth, the combination of R888s (295x35 19) and TRD differential was amazing when *ahem* "testing" the new Syvecs setup with Ryan last night - not a single instance of wheelspin and sideslip despite putting down 29 psi on a 71mm! However, many have noted that the TRD diff is designed more for drag-racing than road-racing.

I'm not into drag racing, track & road work all the way. I also don't understand what help a diff would be when drag racing (i.e. when you're driving in a straight line) and why one diff might be better suited to drag racing or track/road work than another? I guess it's the amount of slip allowed; do drag diffs allow very little slip?

 

I'll be looking at getting a old set of yellow billies as I can get them rebuilt and valved to suit. Then select the correct bump stops, springs and bushes (possibly Rose Joint the arms) and get the biggest set of roll bars made that physically fit and enjoy. I hate spine crushingly hard suspension especially then it's not needed for road / track day use.

 

Lyndon.

I thought I'd heard rose joints were just for the track addicts, and an expensive step for comparatively little return? I'm also not sure one size fits all in terms of anti-roll and spring/dampening rate: wet & dry, road & track, all require different setups to be optimum. That's why I like the EDFC; you can feel a difference in how the car behaves on track when making change to the settings, plus the slight bit of extra comfort you can dial in (i.e. set to 'maximum softness') when on the road is appreciated. Hmmm...

[Dnk]

Stiffer adjustable arb's to help lose some of your body roll

[Kirk]

In complete honesty Steve forget about strut braces. IMO there pointless on a Supra as most of the suspension flex will be transferred through the lower subframes with it being a double wishbone design, the strut towers are nothing more but a mounting for the coilovers. Now if it was a 4 point brace similar to the picture below then it would potentially offer some extra rigidity as the towers are linked to the bulkhead:

 

http://www.lincah.com/wp-content/uploads/2009/02/2010-aston-martin-v12-vantage-engine-picture-588x441.jpg

 

Fitting a cage would achieve a better result.

 

As DnK said stiffer ARB's would help a little with body roll although personally Id just fit a Cusco front ARB and leave the stock rear and then buy some decent 3 way adjustable coilovers e.g. KW's or Nitrons, and fine tune the handling. Bare in mind body roll is dictated mostly by the coilover so choosing right the first time will help massively.

 

As for bushes I'd have to agree with Nic, new OEM parts would be much better even though they are crazy ££££. Bushing an entire car would take twice as long not to mention being an utter pain in the rear to do. The only thing id polly bush is the ARB's.

 

Are you still running the stock diff? If so that may well be something else to look at as well.

[SteveR]

Yeah still on the stock diff, Ryan said a few years ago he thought something strange was going on with that (it always stepped out on the same side when pushed hard and beyond traction limits - he was mapping it at the time!) so I'd had in mind taking a look at what was going on there. What would be an upgrade? The TRD diff or something else? This talk above of the TRD diff being suited to drag racing has me confused.

 

Surprised people think I should get rid of even more body roll - I thought mine was pretty good (I am pushing the road tyres to their limits in the pictures above!). I know sticking 888s on the car will make it roll more (as the cornering will be even harder), so I take the point! Good advice re the 3-ways being key to changing the body roll, I had forgot that... not sure I can afford 3 ways though, 2 ways aren't that bad a compromise, or are they?

 

BTW Martin the picture link in your post isn't working for me; I have the broken JPEG logo. Cheers for the advice Martin & everyone

Edited May 29, 2012 by SteveR (see edit history)

[Littler]

Yeah still on the stock diff, Ryan said a few years ago he thought something strange was going on with that (it always stepped out on the same side when pushed hard and beyond traction limits - he was mapping it at the time!) so I'd had in mind taking a look at what was going on there. What would be an upgrade? The TRD diff or something else? This talk above of the TRD diff being suited to drag racing has me confused.

 

Surprised people think I should get rid of even more body roll - I thought mine was pretty good (I am pushing the road tyres to their limits in the pictures above!). I know sticking 888s on the car will make it roll more (as the cornering will be even harder), so I take the point! Good advice re the 3-ways being key to changing the body roll, I had forgot that... not sure I can afford 3 ways though, 2 ways aren't that bad a compromise, or are they?

 

BTW Martin the picture link in your post isn't working for me; I have the broken JPEG logo. Cheers for the advice Martin & everyone

 

Through doing a little research as I have considered similar options to yourself in terms of what i want out of the Supe I found the OS Giken diff kept being mentioned for being more suited to a track setup. Now whether this would compromise the road aspect I'm not sure but people more informed than me will be able to comment on the Giken diff, but thought I'd throw it out there as another option

[Kirk]

Its alright Steve was only a picture of a DB9 engine bay. If you google it you will see what I mean.

 

2 ways wouldn't be a bad compromise at all mate, hell a decent enough shock like Bilsteins properly spec'd are more than capable of doing the job you want them to do. 3 ways just give you that ability to fine tune and experiment a lot more freely.

 

Diff choice will be purely down to how far you want to go with this experiment. A TRD diff is fine for track days. Mike Ward gets on just fine with his and the car feels fine and grips well on track. As much as CW will disagree with what I'm about to say I'd go with a TRD unless your going for an out for out race spec in which case the Giken would come into its own.

 

Just food for thought really mate

Edited May 29, 2012 by Kirk (see edit history)

[SteveR]

All good info - stuff to think about like you say - that's what's I'm after.

[Mike B]

Not that I am an expert, done some track days on slicks, road tyres, dry and wet, different courses and 3 different sups, few different setups.. and a fair amount of driving on rougher country roads..

 

- Poly bushes, for me, sketchy and mine constantly moved the geo as they were not a good fit in the arms..

- Wheel offsets and size.. my final wheels are 18 inch and as close to stock offsets as possible - they bring much more reliable predictive handling.. 19's were a disaster.. I also have a set of of your wheels (lexus) that I keep the slicks on.. they were good wheels on the road too.

- cw susp is the best I have had, and used 4 different setups. I've had stock, some kind of apexi, KW.. the Cw suspension is excellent... esp on rougher roads.

 

Current car uses;

Trd diff

Updated roll bars front and rear

Stock bushes

Cw susp

18" super light wheels with stock offsets

 

When cw set up the geo the handling was immense.. I had use of an R34 at the time and I have to say I preferred my car in many ways... A bit aggressive on road when pushed, but then it had a lot of grip, so it didn't suit the rougher roads too well as it's not soft enough to smooth out everything under load...

 

The slicks (and I still have 3 sets bought of a bttc team) are immense! They do start to overload my suspension on a warm day though and they will overpower my 355 rotors under heavy use. Their grip is astonishing, and the wear rates of the slicks.. on track they last 10x longer than road tyres which just melt! Cold they are liability, I can see why they are illegal on the road.. lol

 

I'd also say.. alignment for me; crucial. Good geo set is night and day!

Edited May 31, 2012 by Mike B
additions (see edit history)