Ron Simonds' Coilover Suspension - Thoughts?

[julianB]

I have it. I love it.

Reality check: where can you find better for the outlay?

Are you driving a Tarmac rally car or competing at multiple race tracks with a race car?

If so, a bespoke coil over setup is what you want, with adjustable bump and rebound and you're best off calling Heasman's in Sydney to have some Bilsteins built for you.

Ron Simons ran a bunch of 75s at the Nordschleife and this was the kit he developed for them, before offering it for sale- this isn't the smoothest track, from experience, and the karrousel is downright bumpy.

If you're a weekend warrior/occasional track day guy, there is nothing that comes close to the RS setup- everything clears the UCA and they don't crash over bumps anywhere near as badly as big torsion bars do.
Yes, the major criticism with the RS kit is the short(ish) stroke of the kit, but you tell me one thing about these cars that isn't a compromise to begin with?

Combined with Vin Sharp's knuckle riser mod (because upside down ball joint is probably best left to the racers), the car handles ridiculously well.

I will be looking to seam weld some engine bay bits when my car goes in for panting,

Duk, what's your setup on your car?

[Duk]

they don't crash over bumps anywhere near as badly as big torsion bars do.

This is a function of the type of damper used, because at the end of the day a spring is a spring (maybe with the exception of air bags).
I know that some people say you leave the main coil spring floating to help get a better ride, but there is no way that should be done.

Duk, what's your setup on your car?

My car has been off the road for a million years now.............. 

Before I turned it into a shed orniment it had a very mild but effective set up. Mild because I still needed to do a lot of learning but effective because it made very big improvements to a car I was initially very disappointed by.
So my 75 Potenziata had Pace Engineering top balljoints/knuckle risers, a pissy little 105lb/in additional spring (like I said, I still needed to learn a lot more) over Koni adjustables, with King springs lowered rear springs (of what ever rate they were).

What impressed me was the fact that it went from having a very lethargic turn in, with lots of understeer to having a great turn in and much, much more front end grip.
The thing still had a fare bit of body roll, but the antiroll bars were standard, the guestimate spring rates were way to low (but still reprisented a decent upgrade over standard) and the Koni's lack enough low speed bump damping to really help with weight transfer type body movements (before they then go on to have too much high speed damping and become over damped).

As it sits in the shed now it has additional 375lb/in springs at the front, 175lb/in springs at the rear (but I think 200lb/in springs might be a better overal rate), the beginnings of a tubular front antiroll bar that should have a rate very similar to a solid 27mm bar (but weigh a lot less), bumpsteer correction to work with the Pace Engineering balljoints, 105 caster arm balljoints, seam welded inner box sections, a 4 point chassis brace and Series 6 Mazda RX7 16x8 wheels on hub adaptors.
The big want is to figure out Bilstein dampers. But I'm a stuborn prick and that would all be done by your's truly rather than pay someone else to do it.

Removing a lot of weight from the front of the car, especially the heavy impact absorping bumper bars and gas mounts, relocating the battery and maybe some carbon fibre body pannels are all on the 'to do' list.

Worse than all of that stuff written, Doctor Frankenstein lives inside my head................ 
These days I dream of custom made longer suspension arms, Series 4/5 RX7 wheel hubs (in aluminium) and use the Series 6 RX7 wheels (+50 offset with these) without any hub adaptors/spacers, all to get the steering scrub radius a lot lower (which should allow me to use 225 wide tyres on the 8" wide rims rather than the 215/45 tyres only just fit in there with steering lock applied (high steering scrub radius).
There should be a nice reduction in unsprung mass from those mods should have an overal reduction in weight.
On top of that, I want to have dedicated coil springs (kinda must for custom made lower control arms), maybe even move the top damper mount outwards (to get the damper's motion ratio higher),.
And then create some modified spindles with upside down lower balljoints (I'd slightly shorten the lower section to give better wheel clearance). The required steering arm bending would mean the arms are a bit shorter and that would slightly quicken the steering. But on top of that, the ackerman angle of the steering arms would also be corrected (and it's not right in standard form)........................



Sorry. 

[julianB]

You're venturing into a realm of mods that is well past what most of us are capable of!!!

For what i wanted, and probably most of us (bolt-on mods with enough scope to adjust for how we like the car to behave), the RS kit is the best option.

I would advise people to contact Heasman if they want a more tailored option- Bilsteins are awesome, after all.

I'll illustrate my experience and then I'll bow out.

My car was a 2.0 that got a 12v V6 transplant.
16x7.5" wheels, 205/50/16 Bridgestone something or others.
It had Bilstein shocks, 105 castor rods, 1.5" lowered and 20% (from memory)  stiffer rear springs from King.
Stock AR bars. Stock watts link, Poly dedion bush.
I've forgotten, but it may have kept (and may still have) the old 4cyl torsion bars in it. I did those mods 14 years ago and covered about 20,000kms on it.

It rode bumps beautifully, probably because the torsion bars were under-done for the V6.
It understeered on turn in, fell over on the front end mid corner and behaved itself on exit, putting the power down nicely and steering pretty well. If you entered a corner hot and either trail braked or lifted off, you'd end up rotating and needed to be prepared to catch it.

Obviously, the front end understeer was crap and no one would want that.

Now:
105 castor rods, stock AR bars and Poly de Dion bush.
Changed: RS kit (added to torsion bars), PACE knuckle risers.
17x7" Wheels and 215/45/17 Bridgestone and Goodyear something or others.
How it drives:

Night and day.
Turn in is sharp. The steering is telepathic. I look where I want to go and the car changes direction.
Small throttle changes adjust car attitude nicely and precisely.

The only area where the car is not as good as before is the way it ride bumps.
This is to be expected when you increase the spring rate.

I can't say how the kit goes without the knuckle risers, but what I can say is that with the two, I've shoved it up the inside of R32 GTRs, S15s, and Type R Integras on public roads where I shouldn't be doing that, with ease.

I was always told to "fine tune" the car with AR bars, so once my GTA swap is done and I have the car running on Semi-slick shod 156 superturismo rims, I'll sort that out when I get a little more track active.

It is very easy to look at a "desirable" engineering outcome and say that the kit is not ideal, but I stand my ground in saying it is the best option for an Alfetta/162 chassis in existence because you bolt it on and get a massive improvement.
I'd go so far as to say that after fitting a TS 4.1 box with a shimmed out LSD, this is the best mod you can do to the car!

[deano]

Interesting discussion - I need to read more....

Off topic but thought I'd add my own experience with the whole TS box in 3.0 thing as it was right after breathing on the list of life priorities for me a few years back.

3 months and 7,000 kms in the Macedon ranges and I can say its not really worth the money nor effort. The car got fitted with my old now new TS box - fully rebuilt, 50% LSD, lightened clutch etc. I barely noticed it at first (to the point where I thought I'd put the wrong gearbox in the car) and only really feels different in 4th/5th on the road.

Doing it again I'd do the early Alfetta gear-set and 4.3 final drive then it might be worth it on the road. Track driving - not sure - I'll find out later this year hopefully, if I get my act together and lock myself in the shed a few nights a week.

[gtv6sv]

Gtv6sv, in response to your original questions, what are your goals/use for the car but just as important what else have you done to improve it? Or plan to do. For example wheel and tyre size have an impact on suspension setup.

My goal is to have a quick road car which will see the occasional track day here and there.
Car will be sitting on 17 x 7 wheels(road), plan on doing Vin sharps upgrades and also adding the watts linkage upgrade. Now I'm just seeing if it's worth going the coil over set up or go the torsion bar way.
JulianB, how did you find installing the suspension? Any mods required? Do you find you get flex in the chassis from it? I take it it holds the road quite well😊?

[julianB]

I purchased the Watts linkage from Ron but I didn't realise it wasn't kinked on one of the arms, so it doesn't clear my exhaust- that's something I will need to deal with later on.

I also didn't fit the suspension- I don't have the room to be able to do stuff like that in my unit block. No mods required.

It handles brilliantly on my car. The change in direction is great. You can feel a bit of flex from time to time. And as I said earlier, the only criticism I have is the rather short stroke of the shock.
If I were to build another Alfetta, I would never even consider going to bigger torsion bars- it would be RS or Heasman's Bilstein setup. I can't see myself changing the suspension out to anything else.