rear H&R fitment

[sambb]

I spoke to bilstein before fitting my rear B8's to check that they didn't have an internal bump stop like the fronts. They said to fit the OE bump rubbers on the damper shaft. So two things:
- is there enough travel with 30mm drop H&R's to not be into the bump rubbers too early. Do they need to be trimmed?
- The H&R's look really coil bound at the top tighter wound coils when its on the ground. I have seen this before so I'm pretty sure its right but just checking??

thanks
sam

[h100vw]

I'd take a bit off them Sam. I have some spare bumpstops, if you need some full length again in a rush. Just ask

[sambb]

Dam I thought so. With the shaft shrouds on it was really hard to work out how much travel there was left. If they are a 30mm drop over standard does it follow that you lop 30mm off them.

[seangti]

- is there enough travel with 30mm drop H&R's to not be into the bump rubbers too early. Do they need to be trimmed?

I don't believe they'd need to be trimmed at 30mm lower. I don't believe mine have been trimmed (I didn't install them) at 50mm lower springs. My car will hit the bump stops on big humps, back country rounds aren't so great.

- The H&R's look really coil bound at the top tighter wound coils when its on the ground. I have seen this before so I'm pretty sure its right but just checking??

So this is the ~50mm lowering H&R spring with the Bilstein struts.



This is the H&R coilover on the red car.


I've reached out to H&R to see if they have a firmer spring I can put in the rear so I can run less bar and get more wheel travel. Also have a factory front sway bar I may reinstall, as currently it's a whiteline adjustable bar. Wanting more roll in the front and lift in the rear as I felt understeer/wheelspin even with the LSD. So need to get the front end working more.

[nat225]

I know how it feels when the car hits its bump stops... it didn't feel good.

[sambb]

Sean I had some back and forth emails with Mark Ortiz a suspension guy who rights for Racecar Engineering about the inside rear lift question. I wanted more rear roll stiffness to get the inside rear in the air but had maxed out the rear anti roll bar. His response was that in our rear ends, the torsion beam + anti roll bar is the determinant of the inside rear will lift, not the spring rate. The bar and torsion beam is what forces the inside rear to follow the outside wheel up and into the air. You would only go to stiffer rear springs if you were running out of travel on the outside rear because you would not want the outside rear to hit its stops when its the only wheel on the ground. He said that our rear end runs the torsion beam part of the assembly up very close to the pivots on the chassis. This has the effect of lowering the roll centre and making the rear end operate almost like a semi trailing arm suspension. But the catch is that the torsion beam part of the rear end is not very efficient as an anti roll bar. So he said the solution for our rear end (if what you want is to get the inside rear in the air) was for me not to run more spring, but to run more bar provided it still rode the bumps well. In contrast a mates clio that has the torsion beam further out from the pivots doesn't even have a rear bar and when parked on the mildest slope will sit there with the inside rear in the air.
I recently spoke to whiteline about custom bars and they said that there is a mob on nsw south coast they know of who could knock out a custom rear bar. Whiteline don't do them anymore apparently. Maybe call whiteline and see if you can get a lead on that? For the time being i'll see how the H&R rears go and may go down that avenue myself.

re the front end I found these articles that could help with what to do:


April 2000

In the second part of that article he talks about using rim offset changes to induce castor jacking. What it actually does is when you have some lock on, it forces the inside front and outside rear into the ground harder and causes lift on the outside front and inside rear. So it will square up the front cross percentages and lift the inside rear - but only when you have lock on. He says in that article for that reason you run more castor jacking on tight courses and less on faster open ones. When you think about it that's exactly what you need in a FWD. The V8's use tonnes of it so that they can turn in well with their rear lockers and go karts too especially in the wet when they need it the most to stop understeer. I moved from negative scrub radius et43's and added a 12mm spacer to make them ET31's. The car was friggin woeful and had all the symptoms they describe for zero scrub. I then went to 20mm spacers taking it to ET23 and out into positive scrub and it now turn in like a demon, is more stable mid corner and less inclined to spin the inside front on corner exit. It looks a bit mong but has been brilliant. I then squared up the rear track by putting the 12mm spacers there and its great now. Interestingly the same front and rear track as the old model fiesta XR4 now. Steering gets heavier and there is a lot more feedback including steering kick though (due to the positive scrub it has now) so not sure how that would play out with your LSD. Apparently if these symptoms are excessive you can go to a bees pecker of toe in to counteract. Main thing is you want to either have lots of negative scrub or positive scrub but not zero. On the british hillclimb forums lots of guys withgolf mk 2's etc are doing this - moving from negative to positive scrub. I can send you more stuff on this if your interested. Its cheap to try - just add spacers!

[sambb]

oh and thanks for those spring pics. Same as mine so sweet. They must be a rising rate spring as the coils bind up one by one like that. The weitecs I took out are linear rate so it'll be interesting to feel the difference. I just got off the phone from bilstein and they thought that the rear should be ok with the stock length damper rubbers fitted. I think i'll just drive it like that and see if I hit. Don't have the stomach for any more car work right now. The garage floor is too cold down here atm.

[simon k]

I spoke to bilstein before fitting my rear B8's to check that they didn't have an internal bump stop like the fronts. They said to fit the OE bump rubbers on the damper shaft.

there's my answer Sam!

[sambb]

yep I remember fitting them. To make me feel more certain/safe for you though, put some cable ties around the shafts as tell tales just in case I was muddled and they didn't need to go on.