BMW test build

Poor Grant.....



But modern car shells are designed to take side impacts too. That is relevant if losing control and hitting a tree in the woods. My point was the shells are very strong in comparison to the older cars. I reckon a modern car could literally drive through a mk1 Golf if it T boned it.
Here is a "tank" of Volvo 940 versus a little Renault Modus. Skip to 1.40 for action.




Yep the suspension on some new cars like some old cars may be weak but that can generally be worked on with a bit of thought.
And that brings it back to Grant's car. Are you going to do anything to the rear end as iirc the saloon E36 is different to the compact E36, the latter using the E30 design and is considered stronger?
Also interesting to see inside the BMW lsd, I thought there was a viscous element to them, maybe that is just the later ones.

---

Disappointingly not yet a Jackass

Quote
danster
Poor Grant.....



But modern car shells are designed to take side impacts too. That is relevant if losing control and hitting a tree in the woods. My point was the shells are very strong in comparison to the older cars. I reckon a modern car could literally drive through a mk1 Golf if it T boned it.
Here is a "tank" of Volvo 940 versus a little Renault Modus. Skip to 1.40 for action.




Yep the suspension on some new cars like some old cars may be weak but that can generally be worked on with a bit of thought.
And that brings it back to Grant's car. Are you going to do anything to the rear end as iirc the saloon E36 is different to the compact E36, the latter using the E30 design and is considered stronger?
Also interesting to see inside the BMW lsd, I thought there was a viscous element to them, maybe that is just the later ones.

YouTube has stacks of ADAC (Germanski Auto Club) crash tests vids..
My beloved Sierras dont look too nice compared to a stinkin newish Fiesta in these frontal tests...
Downright scary in fact.. Fortunately US versions have some mitigating additions, like a stay on the steering column to help not spear your chest..


The diffs in those Bowel Movement Wonders are pretty damn nice, just like a bigger and stronger version of the Salisbury diff in rwd Escorts, in fact its same guts (except splines) as Atlas...

Of course Grant wants to fuck with the ramps when for RWD is perfectly fine as it is, just wants more preload.

Grantie-poo, all that variable ramp shit if for Fail wheel drive especially on asphalt....don't worry about that.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
john vanlandingham
Grantie-poo, all that variable ramp shit if for Fail wheel drive especially on asphalt....don't worry about that.

That and if he'd quit lifting all over the place, the decel wouldn't even matter. Buh-gaWK!

Dave

Quote
danster
And that brings it back to Grant's car. Are you going to do anything to the rear end as iirc the saloon E36 is different to the compact E36, the latter using the E30 design and is considered stronger?
Also interesting to see inside the BMW lsd, I thought there was a viscous element to them, maybe that is just the later ones.

I don't believe in thread derailment. Conversations occur for a reason, but thanks for the effort to bring it back on topic.

Not sure that I'd say stronger but there are definite disadvantages and advantages to the rear suspension design of either.
The STA setup of the Compact, which is like E30, is easier to reinforce but more difficult to adjust settings. There are also likely greater changes in camber and toe as you go through the range so changes to static ride height can result in weird camber with no load.
The multi-link setup of the Coupe/Sedan has more arms to fail and more bushings to purchase. The biggest issue in my mind is that the rear shock mount is pretty lonely, exposed, and unsupported. This isn't an issue until you get into coilovers and now that one little piece is taking all the shock and providing all the support. Recipe for failure.
Both cars (and the Sierra/Merkur) have shock and spring seperate. One problem with this is that when you go to a coilover you end up moving the pivot point of the bump stop further out and start bending stuff differently. I have bent the inner mount resulting in more camber on Merkur rear beams twice now. One of your countrymen did probably the same thing to a Compact.
There are solutions. Easiest would be to leave spring and bump stop seperate from the coilover. Hydraulic external bump stops in the spring location is another. Basically try to remove some of the shock that occurs to the mounting point/shock under full or near full compression to another location.

Anyhow, gotta jet. Need to finish standardizing this dataset, perform a little ANOVA and create some boxplots for a presentation next week to the NIH and then head over to the junkyard where I hope to find a beautiful 4.10 diff. With luck it will also be limited...

---

Grant Hughes

Grant, all the significant stress comes from the damper slowing things down.. Think about not whatever you read somewhere, its mostly garbage, think about the stress if there was NO SHOCK . Compression forces would be only a little 175 lb/in spring and the wheel would just be batted up

(That's the beauty of trailing arm set ups Car <-------- that way..force ----> way.. o------------^ force rearward , arm goes up freely (that's an arm)..
Shit breaks from compression being strongly resisted. This is especially true is the valving is hard or "spikes", the stress going up straight up---basically hydro-locked..
That's when shit breaks/bends

And again yes camber and toe occurs..

look at current WRC gravel cars in the air. They have like 8-10^o positive camber at full droop.. god knows what toe and god knows at full compression..
Obviously big changes..

Do they look worried?

Don't worry, you'll never feel it...
So TRUE but the significance is immeasurable.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
john vanlandingham
Grant, all the significant stress comes from the damper slowing things down.. Think about not whatever you read somewhere, its mostly garbage, think about the stress if there was NO SHOCK . Compression forces would be only a little 175 lb/in spring and the wheel would just be batted up

I did a few hundred miles of a TSD with no shock in the rear in my first rally car, a FWD 84 Colt. Just the spring. That car was much lighter.
Harry Hockley Motorsports sells a weld on bump stop for the stock spring location. I can only assume the purpose of that is to move leverage point to somewhere more neutral (once your slammed onto bump stop you aren't leveraging so hard on the inner STA mount but kinda evenly on both?) and to reduce some of the shock seen on the mounting point under full load?

Quote
JV
And again yes camber and toe occurs..
Do they look worried?
Don't worry, you'll never feel it...
So TRUE but the significance is immeasurable.

I am so totally not worried about the change. In fact, I have said something along the line of, "Ya'll are fucking stupid" in regards to people wanting to spend ANY money on the so called "6 degree" rear beam and arms. I am not a suspension engineer nor do I have the thousands of dollars or millions of hours (switch that) to test and test and figure out what the optimum setup is for my car. The more you change the more you FUCK up what someone that is WAY smarter than you designed. I've said essentially that to multiple people, especially engineers.
However, being able to adjust camber just a bit so that at static height you don't have +2 degrees with the new raised ride height would be nice on some stages/cars.

---

Grant Hughes

On the rear beam cars its as simple as welding on a few tabs so that you can use an eccentric bolt. I know there are kits out there and have even spotted modded rear beams for sale on eBayUK, but I haven't felt the need to mess with any of that on the Compact yet. Its "good" enough...I do want some more droop travel though.

Dave

Quote
DaveK
On the rear beam cars its as simple as welding on a few tabs so that you can use an eccentric bolt. I know there are kits out there and have even spotted modded rear beams for sale on eBayUK, but I haven't felt the need to mess with any of that on the Compact yet. Its "good" enough...I do want some more droop travel though.

Wait. So you are saying it's good enough for one thing and then saying you want more droop travel because 8" of travel in the rear isn't enough or because you really really want to find out the limit of articulation in the BMW shafts and see if you can start blowing those up next?

Sean did the eccentric bolt thing on the Merkur beam. Yes, there are ways to change the camber and toe on the rear STA. Camber and toe is super easy to do on the multi-link comparatively. Is it necessary on either car? Not likely.

The biggest benefit in my opinion is the engine and availability. The Compact only came with a 1.9 4 cylinder and they are a little lower in production volume. The Coupe/Sedan has the 2.5 6 cylinder and they made a ton of them.

---

Grant Hughes

Quote
NoCoast
Wait. So you are saying it's good enough for one thing and then saying you want more droop travel because 8" of travel in the rear isn't enough or because you really really want to find out the limit of articulation in the BMW shafts and see if you can start blowing those up next?

Not changing my car at the moment. Again, when I was using the Stig's Group A dampers for testing, or the ones that I've got on the car now with the 1" spacer at the top, I didn't have any catastrophic axle failure. The reason I've lost droop travel is because of where the towers got welded in (best guess at the time) necessitated the removal of the 1" spacer so we lost droop. I see zero reason not to try to gain that back for future builds if it doesn't change the costs of the builds.

Quote
NoCoast
The biggest benefit in my opinion is the engine and availability. The Compact only came with a 1.9 4 cylinder and they are a little lower in production volume. The Coupe/Sedan has the 2.5 6 cylinder and they made a ton of them.

Yep, but buying a compact with a blown motor means even cheaper starter car and because of all the 2.5s around, finding a used one of those is cheap too. Certainly adds to the to-do list, but its not an unreasonable thing for many folks to consider.

Certainly not arguing that the 325 isn't the best/quickest way on stage with a fun car though. Personally, I'm betting I'd rather drive a stock powered 325 than a stock powered 318ti...but if you have someone who knows an engine swap is going to happen, I think that takes care of the big downside that the compact has.

Dave



Edited 1 time(s). Last edit at 01/10/2013 04:01PM by DaveK.

whoops!



Edited 1 time(s). Last edit at 01/10/2013 04:00PM by DaveK.

Some people, engine swap is fine, others it is just a delay. There are six or seven 2.5 engines in junkyards I've seen this week. Two four door sedans. Got my 4.10 final drive diff today. Interesting method. Pulled arms and popped out stub shafts to avoid having to fight all 12 cv bolts. Drop whole frame and pull it out first.

---

Grant Hughes

Quote
NoCoast

Quote
john vanlandingham
Grant, all the significant stress comes from the damper slowing things down.. Think about not whatever you read somewhere, its mostly garbage, think about the stress if there was NO SHOCK . Compression forces would be only a little 175 lb/in spring and the wheel would just be batted up

I did a few hundred miles of a TSD with no shock in the rear in my first rally car, a FWD 84 Colt. Just the spring. That car was much lighter.
Harry Hockley Motorsports sells a weld on bump stop for the stock spring location. I can only assume the purpose of that is to move leverage point to somewhere more neutral (once your slammed onto bump stop you aren't leveraging so hard on the inner STA mount but kinda evenly on both?) and to reduce some of the shock seen on the mounting point under full load?

Huh? translate man I have no idea what you're going on about??
Engrish, mutha farker

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
DaveK

Quote
wvonkessler
BMWs rule.

Plus no guy ever got laid driving a Merkur.

New signature for Grant?

Aaaaaand the diet dew is coming out of my nose.

---

Kirk Coughlin
Woodbury, MN and River Falls, WI

Quemadmodum gladius neminem occidit, occidentis telum est.

Just for some clarity...
There are three sizes of diffs based on diameter of ring gear. 168 mm, 188 mm, and 210 mm. The bearing carrier in the 210 mm diff is 8 bolt and is mostly used in V8/V12 cars. Small case's rear cover is held on by six bolts. Medium case is held on by eight bolts. But best is to just make sure you're looking at a six cylinder car and you've likely got a medium case diff.

Cars to climb under and look at the tag for (or just spin wheels first, spin same direction side to side, LSD, spin opposite direction indicates open diff):
E32 BMW 7 series with the 6 cylinder
E34 everything but M5 and 540i
E36 6 cylinder cars
E30 6 cylinder cars

If you look at the metal tag on the rear cover it will tell you the final drive. If it has an S before, it's a LSD. Which had LSD varies widely. The final drives however should be standard. Here's the ones to look out for.
4.10 are in auto E30s and manual E30 M3s
4.10 in 89-93 525i with an auto trans
4.27 in 91-93 535i with an auto trans
4.27 in 91-92 735i

The CV bolts are a bitch. In the 5 series cars I just drop the entire rear suspension and drag it out from under the car. If the CV bolts are really difficult, it's easy to remove rear arms and pop out stub shafts and just take the diff without those. If you have a helper it's not too bad to get CV bolts out. Otherwise it sucks.

---

Grant Hughes

Whats a bitch about the CV bolts? I've seen XZN and external Torx, are you just a limp-wristed weenie boy? Might explain the fascination with Bee Ems..

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.