Hi guys I need some assistance with my e30. The car is a 84 323i chromie. I have changed the hubs on the front to 5 hole and reworked the rears as well to accommodate 5 stud.
The offset of the hub has not changed as I used a sleeve to accommodate the m3 hub on the standard spindle.
What I have in terms of suspension is the following
Blistein b8's front and rear
H&R springs 30mm drop
Lemferorder drop links new
H&R anti roll bars
Power flex bushes all around, including e30 offset lollipop
New front trailing arms, with new ball joints
What I have in terms of wheels.
Work rezax ii 8j fronts
Work rezax ii 9.5j rears
These are 18in, I got the idea from felgen garage pic .
I find the car is really floaty on the freeway and I can move the steering a fair amount (about an inch) in a straight line before the car reacts, I have changed the guibo in the steering column as well.
None of this has made a difference to the car, I have a distinct lack of confidence at higher speeds as I am scared she will veer off in another direction.
Could this be related to the steering rack........oh and the tracking has been checked and is fine.
Or could the wheels just be too big and I am loosing control over this, I have not heard of this before with bigger wheels tbh.
Suspension gurus needed
Moderator: martauto
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HairyScreech
- Engaged to the E30 Zone
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Its possible you have actually changed the offset.
What hubs etc have you used at the rear?
What are your wheel offsets?
At a glance you may be looking at 20mm spacers at the front at least.
What hubs etc have you used at the rear?
What are your wheel offsets?
At a glance you may be looking at 20mm spacers at the front at least.
2.8 development thread http://www.e30zone.net/modules.php?name ... c&t=170822
m3.3.1 m20 thread - now running, chip needed - any volunteers?
http://www.e30zone.net/modules.php?name ... =viewtopic&
m3.3.1 m20 thread - now running, chip needed - any volunteers?
http://www.e30zone.net/modules.php?name ... =viewtopic&
Its very possible that I have , I had to , the front runs wilwood calipers and custom brakes.
The only stock wheel which fits on without touching the caliper is an E36 M3.
I need to measure the offset on the fronts but the wheels sit inside the fender and dont rub.
The rears are the stock E30 hubs, we machined a plate to fit behind the stock hub, then put studs in so we would not need to worry about bolts fouling on the handbrakes.
The rotor fronts are drilled and slotted for 5x 120. It was a cheaper and more robust solution then retro fitting Z3 Arms and does not change the rear geometry.
The only stock wheel which fits on without touching the caliper is an E36 M3.
I need to measure the offset on the fronts but the wheels sit inside the fender and dont rub.
The rears are the stock E30 hubs, we machined a plate to fit behind the stock hub, then put studs in so we would not need to worry about bolts fouling on the handbrakes.
The rotor fronts are drilled and slotted for 5x 120. It was a cheaper and more robust solution then retro fitting Z3 Arms and does not change the rear geometry.
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stevesingo
- E30 Zone Newbie
- Posts: 77
- Joined: Mon May 15, 2006 11:00 pm
- Location: Cumbria
From experience and testing...
The H&R springs are way too soft on the rear. As a comparison an M3 has 100lb/in front and 300lb/in rear. The H&Rs are 200lb/in front and 285lb/in rear. When we convert this to the wheel rate we get M3 87fr and 123 rr comapred to H&R 178fr/116rr.
What you are experiencing is excessive roll at the rear which is preventing the front from reacting. When turning the front wheels and inducing a yaw motion, the front wheels need something to work against, the rear. If the rear is too soft the response from the front is dulled until the rear has absorbed it's part of the load. With the excessive roll, the front has to wait until the rear has settled. This is what gives the unresponsive floaty feeling.
Basically a imbalance of front to rear roll stiffness.
What will also add to the imballance is the front is not only too stiff in springing, but it is likely you are sitting on the internal bumpstops of the Bilstiens. The Bilsteins have about 160mm of stroke, but also have 80mm bump stops. God only knows why!
You can trim the bumpstops down to 30mm or so, which allows the spring to take the load of the car in normal circumstances, not sat on a stiff urethene bump stop.
http://s14net.vbulletin.net/forum/s14/g ... ill?page=4
The H&R springs are way too soft on the rear. As a comparison an M3 has 100lb/in front and 300lb/in rear. The H&Rs are 200lb/in front and 285lb/in rear. When we convert this to the wheel rate we get M3 87fr and 123 rr comapred to H&R 178fr/116rr.
What you are experiencing is excessive roll at the rear which is preventing the front from reacting. When turning the front wheels and inducing a yaw motion, the front wheels need something to work against, the rear. If the rear is too soft the response from the front is dulled until the rear has absorbed it's part of the load. With the excessive roll, the front has to wait until the rear has settled. This is what gives the unresponsive floaty feeling.
Basically a imbalance of front to rear roll stiffness.
What will also add to the imballance is the front is not only too stiff in springing, but it is likely you are sitting on the internal bumpstops of the Bilstiens. The Bilsteins have about 160mm of stroke, but also have 80mm bump stops. God only knows why!
You can trim the bumpstops down to 30mm or so, which allows the spring to take the load of the car in normal circumstances, not sat on a stiff urethene bump stop.
http://s14net.vbulletin.net/forum/s14/g ... ill?page=4
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stevesingo
- E30 Zone Newbie
- Posts: 77
- Joined: Mon May 15, 2006 11:00 pm
- Location: Cumbria
FWIW, I had a set of springs custom made by faulkner springs. 150lb/in Fr and 435lb/in Rr.
THis was for an M3 mind you. A 6cyl car may need a slightly higher front rate, say 165lb/in.
THis was for an M3 mind you. A 6cyl car may need a slightly higher front rate, say 165lb/in.
Sorry to high jack. Can you use e36 front anti roll bar, if using e36 m3 evo hubs and suspension?
I have 24mm H&R front. Probably too big but I'll set it soft if I can use it.
Also can you use e36 rear shocks and springs? I have HSD kit I would like to use.
Cheers
I have 24mm H&R front. Probably too big but I'll set it soft if I can use it.
Also can you use e36 rear shocks and springs? I have HSD kit I would like to use.
Cheers
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stevesingo
- E30 Zone Newbie
- Posts: 77
- Joined: Mon May 15, 2006 11:00 pm
- Location: Cumbria
The problem is a lack of rear roll stiffness, so adding a stiffer front ARB will not help.
Trust me, I have spent the last 10 months trying to arrive at a set of spring rates from AVO to H&R to the Faulkners I have now.
I even went to the lengths of producing my own spread sheet from this thread
http://www.e30zone.net/modules.php?name ... c&t=197634
Trust me, I have spent the last 10 months trying to arrive at a set of spring rates from AVO to H&R to the Faulkners I have now.
I even went to the lengths of producing my own spread sheet from this thread
http://www.e30zone.net/modules.php?name ... c&t=197634
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stevesingo
- E30 Zone Newbie
- Posts: 77
- Joined: Mon May 15, 2006 11:00 pm
- Location: Cumbria
How thick? How thick is the E36 bar? What are your spring rates?
It is a really interesting area to delve in to.
The way an E30 handles is really dictated by weight transfer and load induced roll.
When we get on the power, we get squat and when in a bend we also have roll. The squat causes rear suspension compression which gives camber gain and toe-in which is good for stability. Roll also adds to this on the loaded outside wheel.
Stiffer suspension reduces the roll and squat. If we increase spring rates we reduce roll and squat in a similar proportion. Stiffen the ARBs and reduce roll but make no change to squat/dive.
One of the failings of the E30 handling is that it turns in very well on a constant throttle, but when you get on the gas, they tend to push in so understeer. This is because when the car turns in, the load is evenly distributed front to rear. When we get on the gas, the car squats and gains camber and toe in on the outer rear wheel. This increases stability and we get the understeer.
If we want to reduce this pitch sensitivity, increased spring rats are the way to go, and tune the balance with ARBs.
It is a really interesting area to delve in to.
The way an E30 handles is really dictated by weight transfer and load induced roll.
When we get on the power, we get squat and when in a bend we also have roll. The squat causes rear suspension compression which gives camber gain and toe-in which is good for stability. Roll also adds to this on the loaded outside wheel.
Stiffer suspension reduces the roll and squat. If we increase spring rates we reduce roll and squat in a similar proportion. Stiffen the ARBs and reduce roll but make no change to squat/dive.
One of the failings of the E30 handling is that it turns in very well on a constant throttle, but when you get on the gas, they tend to push in so understeer. This is because when the car turns in, the load is evenly distributed front to rear. When we get on the gas, the car squats and gains camber and toe in on the outer rear wheel. This increases stability and we get the understeer.
If we want to reduce this pitch sensitivity, increased spring rats are the way to go, and tune the balance with ARBs.
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stevesingo
- E30 Zone Newbie
- Posts: 77
- Joined: Mon May 15, 2006 11:00 pm
- Location: Cumbria
No idea.
HTH
HTH
E30 can be modified so an E36 bar can fit, but it's not a bolt-on mod. Requires putting mounts for the ARB brackets & bushes on the chassis rails. Chassis rails may need local reinforcement too.grants50 wrote:So does the e36 bar fit a e30?
Yeah I won't use the e36 front bar, I'll stick with the e30. I want a more oversteer setup too so the 24mm h&r will be too big.
Thanks for all the info lads. Is a great forum. Best info for e30's, other sites generally don't have a clue.
Thanks for all the info lads. Is a great forum. Best info for e30's, other sites generally don't have a clue.
Thanks for the info on the spring rates, I cannot understand how a company like H&R would release something that is not suited for the car. Loads of guys on here swore by the H&R kit.
Some other interesting stuff, I am unable to do a bounce test on the front of the car, it will not compress any further, however driving it along does not feel like u riding on the bump stop , the fender to wheel gap is still about an inch and 3/4 .
I found that Ireland Engineering in the US has a kit which allows you to use a custom spring rate with one of their setup's , this might be cheaper then going and buying a new set of springs.
What are the symptoms of a knackered but non leaking rack. Could it just be that at the dead centre position I have a fair amount of play and this is creating the wayward feeling I have ???
Some other interesting stuff, I am unable to do a bounce test on the front of the car, it will not compress any further, however driving it along does not feel like u riding on the bump stop , the fender to wheel gap is still about an inch and 3/4 .
I found that Ireland Engineering in the US has a kit which allows you to use a custom spring rate with one of their setup's , this might be cheaper then going and buying a new set of springs.
What are the symptoms of a knackered but non leaking rack. Could it just be that at the dead centre position I have a fair amount of play and this is creating the wayward feeling I have ???
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stevesingo
- E30 Zone Newbie
- Posts: 77
- Joined: Mon May 15, 2006 11:00 pm
- Location: Cumbria
I believe the 325 spring rates are 106Fr/245Rr, and I don't think the 323 should be be too different. I had the H&R 29664 tested by Faulkner Springs. They are progressive in rate, but at the installed lengths they are stated above. It does seem odd that they would double the front rate and only increase the rear by 20%. Using these springs on track, I was lifting inside front wheel under power out of tighter corners.
On the bump stops, my M3 is at stock ride height, and when I measured the amount of damper travel used with the car sat still, I only had 5mm before the bump stops. So, as soon as the suspension loaded up in the turns, the load is being taken on the bump stops and the effective wheel rate increases.
I took the struts apart and when I looked at the bump stops they were battered! I trimmed them down to 30mm in length and what a difference in ride quality.
On the bump stops, my M3 is at stock ride height, and when I measured the amount of damper travel used with the car sat still, I only had 5mm before the bump stops. So, as soon as the suspension loaded up in the turns, the load is being taken on the bump stops and the effective wheel rate increases.
I took the struts apart and when I looked at the bump stops they were battered! I trimmed them down to 30mm in length and what a difference in ride quality.
Ok, so got some one else to drive the car aswell , there is a dead spot on the rack , at centre it seems to be more pronounced when turning left then right.
Step 1 , change the rack , when the car is off and you rock the steering wheel there is a knocking noise. you can hear it outside the car and feel it on the actual chassis.
Step 2, order a set of higher rate rears, thinking Ireland Engineering height adjusters as well as sooner or later I am going to have some ballast in the boot. This will allow me to raise the rear and have it adjustable , but also a stronger set of rear springs cant hurt.
Step 1 , change the rack , when the car is off and you rock the steering wheel there is a knocking noise. you can hear it outside the car and feel it on the actual chassis.
Step 2, order a set of higher rate rears, thinking Ireland Engineering height adjusters as well as sooner or later I am going to have some ballast in the boot. This will allow me to raise the rear and have it adjustable , but also a stronger set of rear springs cant hurt.