Street Touring Hatchback (STH) discussion/setup

[q74]

We'll see how the wife feels about it... I'm guessing I'm going to get an earful

Wife knows and sees what I buy, but she has no clue what to expect most of the time (or when I even install parts, sometimes... err... often I sit on parts for months, over a year in some cases, before installing).

I just wait to see if she notices anything different, sometimes she does, sometimes she doesn't.

 

[jmblur]

Wife knows and sees what I buy, but she has no clue what to expect most of the time (or when I even install parts, sometimes... err... often I sit on parts for months, over a year in some cases, before installing).

I just wait to see if she notices anything different, sometimes she does, sometimes she doesn't.

Yeah we have separate "play" budgets so she can't get too pissed.

 

[xXDavidCXx]

Got the Ohlins in this weekend. Waiting for ride height to settle a bit but I do think I need shorter springs in the rear, to get any preload on them at all the car seems to be excessively raked. This is with 200mm 110N/mm springs. 175mm would be about right.

Rear damping was definitely too low at 20 clicks out even with the revalve. 15 feels better, maybe another couple clicks to get it critically damped. Need to play with front too and see where it feels best.

Ride is definitely noticeably firmer but not especially harsh. We'll see how the wife feels about it... I'm guessing I'm going to get an earful

You can’t pre-load the rear springs

 

[JackRabbitSLIM]

Fresh staggered tires go on the car Sunday, curious to see how it feels. I'm expecting it to be fairly loose while the tires burn in, but hopefully it stabilizes. Even if it's a little looser than I'd like, I'll probably leave it alone knowing that a) our local side is fairly slick and b) the car will tighten up a bit in Lincoln

Hey Brad what happened with this?

 

[jmblur]

You can’t pre-load the rear springs

Any problems with noise or unseating with rear droop? I can certainly wind them back for a no preload situation. What length springs are you running? Was figuring I could use 175mm springs with ~20mm compressed height helpers and be in a good spot?

Car as it sits with minimal preload front and rear.

 

[bfury5]

Hey Brad what happened with this?

Car felt good, but didn't get as much seat time as I wanted. My newish dogbone insert started to tear apart. I think that was user error though - when I replaced the trans mount the day before I think I accidentally applied some preload to the dogbone

Edit: also raised the front ride height ~4mm to prevent some rubbing, but need to add 3mm spacers in the front too

 

[JackRabbitSLIM]

Car felt good, but didn't get as much seat time as I wanted. My newish dogbone insert started to tear apart. I think that was user error though - when I replaced the trans mount the day before I think I accidentally applied some preload to the dogbone

Edit: also raised the front ride height ~4mm to prevent some rubbing, but need to add 3mm spacers in the front too

Was the car different or the same with the stagger?

 

[bfury5]

Was the car different or the same with the stagger?

From what I could tell on limited runs it felt the same, but I need another event to be 100% certain. It definitely didn't immediately try to loop or anything

 

[xXDavidCXx]

Any problems with noise or unseating with rear droop?

depends on the rear spring length, no issues with 8 inch springs, 7 may & 6 will need a helper depending on the ride height, the higher the more space needs to be added.

There is a sweet spot, you just have to find the ride height you want then jack up the car to see how much droop you have, then factor in the compressed height of the helper/spring divider assembly and raise the spring perch that amount.

I can certainly wind them back for a no preload situation.

Again, the rear springs can’t be compressed separately from the weight of the rear.

Not sure what you mean when you say preload.

What length springs are you running?

8 front, maybe 7 rear, I don’t remember.

Was figuring I could use 175mm springs with ~20mm compressed height helpers and be in a good spot?

Car as it sits with minimal preload front and rear.
View attachment 221802

 

[GTIfan99]

Any problems with noise or unseating with rear droop? I can certainly wind them back for a no preload situation. What length springs are you running? Was figuring I could use 175mm springs with ~20mm compressed height helpers and be in a good spot?

Car as it sits with minimal preload front and rear.
View attachment 221802

Car looks amazing, BTW.

 

[jmblur]

Again, the rear springs can’t be compressed separately from the weight of the rear.

Not sure what you mean when you say preload.

With suspension at full droop (but with struts installed which limits travel), adjusting the spring perch so the springs aren't loose. Minimal preload is just winding them until they arent loose, additional preload at full droop will raise ride height 1:1 with the amount of preload added.

Measured heights and it's not as raked as I thought it was after settling, so going to leave them as is for now. More drop in the front would be nice but not going to happen without shorter springs and eating into travel, so not going to bother.

 

[xXDavidCXx]

With suspension at full droop (but with struts installed which limits travel), adjusting the spring perch so the springs aren't loose. Minimal preload is just winding them until they arent loose, additional preload at full droop will raise ride height 1:1 with the amount of preload added.

What you are describing is not pre-load, the spring is not pre-loaded to resist initial movement.

All you are doing is just adjusting the ride height by taking up the slack.

You can replace the slack with a spring separator and helper spring. That’s the purpose of these items.

Also, ride height adjustment is not 1:1 because of the spring motion ratio.

 

[jmblur]

What you are describing is not pre-load, the spring is not pre-loaded to resist initial movement.

All you are doing is just adjusting the ride height by taking up the slack.

You can replace the slack with a spring separator and helper spring. That’s the purpose of these items.

Also, ride height adjustment is not 1:1 because of the spring motion ratio.

This is still preload - the spring is compressed against a hard stop (full extension of the shock in this case) Ride height is adjusted same as preload adjusts it in the front (without a separate perch ride height adjustment).

I wouldn't have room for much of a helper spring with 8" coil, and am as low as I can be without having a loose spring at full droop.

Totally right about the motion ratio tho! My bad.

 

[xXDavidCXx]

This is still preload - the spring is compressed against a hard stop (full extension of the shock in this case) Ride height is adjusted same as preload adjusts it in the front (without a separate perch ride height adjustment).

Now I understand, and in this limited scenario, I agree this is what is happening. If you go with a 6 inch spring to lower the rear, you will have too much slack and not enough adjustment to apply preload And will end up needing to use a helper spring.

I wouldn't have room for much of a helper spring with 8" coil, and am as low as I can be without having a loose spring at full droop.

I don’t recommend helpers unless you go with a 6 in rear spring

 

[jmblur]

First autox with the Ohlins on. Holy cow what a difference! Don't have to LFB to get any semblance of rotation now, but if I need a ton trail braking gives it. I was worried it might be prone to snap oversteer like the car was when I had just the RSB, but not so.

Now I just gotta learn how to drive the car again. And maybe get some camber plates, definitely still getting some mid-exit understeer.

Will upload a vid later for some pointers if I can get the software to behave.