E36 BMW chassis parts list

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DaveK
So, with both cars I effectively have a 4-speed gearbox that tops out in the mid-120s. So what I was trying to say earlier is that if you went with a 3.3 rear end, 1st gear would get you an extra 10mph (splitting the difference between 1st & 2nd gear with a 4.3), which might make it useable. 4th gear would top out at a slightly higher 131mph and you'd end up with a pretty comfortable 5th gear (3000rpm @ 70mph vs 3950rpm with the 4.3) for cruising on transits.

The other thought with these motors is that they've got pretty broad torque bands.

I "think" having lower ratio in the rear and higher ratio in the front reduces stresses on the gearbox gears, output shaft, drive shaft, and lesser extent the pinion gear. If the bulk of your torque multiplication is occurring in the rear end instead of the gearbox the stresses on everything between the gear and ring gear is lessened.
I know I have never seen anything advertised as a rally gearbox with a first gear lower (numerically larger) than 2.4-2.5 or so. Not that that means anything...

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Grant Hughes

So what is the consensus on stock or close to stock suspension parts.

Most of the BMW forums want to discus lowering the car. Is there a good stock spring for a more rally friendly ride height?

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Andrew_Frick
So what is the consensus on stock or close to stock suspension parts.

Most of the BMW forums want to discus lowering the car. Is there a good stock spring for a more rally friendly ride height?

My take is that they're not up to the task. I ran JVAB fronts and Billy HDs in the back at a local hillclimb on the Coupe and it felt like I had two different cars under me - ready to run over anything up front, and ready to bottom out at the smallest dip in the road out back.

I really like the JVABs all around that I've got on the Compact, so I'm on the hunt for a proper solution to beef up the rears. I'd prefer to do it without having to add taller shock towers out back.

Regarding springs - if anyone tells you that the rear E30 325 convertible springs are beefier or taller than the E36 ones...they're full of crap. Still trying to find an OEM spring that's beefier than the 328 vert, but no luck so far. BMW pervs are so secretive with everything, it really sucks.

Dave

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NoCoast

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DaveK
So, with both cars I effectively have a 4-speed gearbox that tops out in the mid-120s. So what I was trying to say earlier is that if you went with a 3.3 rear end, 1st gear would get you an extra 10mph (splitting the difference between 1st & 2nd gear with a 4.3), which might make it useable. 4th gear would top out at a slightly higher 131mph and you'd end up with a pretty comfortable 5th gear (3000rpm @ 70mph vs 3950rpm with the 4.3) for cruising on transits.

The other thought with these motors is that they've got pretty broad torque bands.

I "think" having lower ratio in the rear and higher ratio in the front reduces stresses on the gearbox gears, output shaft, drive shaft, and lesser extent the pinion gear. If the bulk of your torque multiplication is occurring in the rear end instead of the gearbox the stresses on everything between the gear and ring gear is lessened.
I know I have never seen anything advertised as a rally gearbox with a first gear lower (numerically larger) than 2.4-2.5 or so. Not that that means anything...

Grant a "LOW" first is 4.2:1 ; a higher 1st is 2.95:1, a typical rally box 1st is 2.25 to maybe 2.35 just to remind everybody

Low axle is 5.35:1 and "High" axle 2.85.. Disregarding what every kid on the intraweb says and reversing it and just sticking with the convention usage sure helps for clarity..
And short AXLE means you don't need the box the size of a 3.5 ton truck box
Then its just a matter of finding a toof count that is good for the ratio and the strength you need. (Road car shit being selected for quietness)

To see this in action look at mid/late 80s Saab 900 T16 gearboxes with the taller chain drive primary ratio to reduce torque to the box, then the replacement of the 3.73 final drive with 3.9 to make up for it.

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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.

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john vanlandingham

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grant
I "think" having lower ratio in the rear and higher ratio in the front reduces stresses on the gearbox gears, output shaft, drive shaft, and lesser extent the pinion gear. If the bulk of your torque multiplication is occurring in the rear end instead of the gearbox the stresses on everything between the gear and ring gear is lessened.
I know I have never seen anything advertised as a rally gearbox with a first gear lower (numerically larger) than 2.4-2.5 or so. Not that that means anything...

Grant a "LOW" first is 4.2:1 ; a higher 1st is 2.95:1, a typical rally box 1st is 2.25 to maybe 2.35 just to remind everybody

Yeah, and that is exactly what I said.

Here, I'll rephrase it...

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grant
I "think" having lower ratio in the rear, like 4.3-5.X and higher ratio in the front like 2.25-2.95 reduces stresses on the gearbox gears, output shaft, drive shaft, and lesser extent the pinion gear. If the bulk of your torque multiplication is occurring in the rear end instead of the gearbox the stresses on everything between the gears in the gearbox and ring gear is lessened.
I know I have never seen anything advertised as a rally gearbox with a first gear lower (numerically larger) than 2.4-2.5 or so. Not that that means anything...

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Grant Hughes

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NoCoast
I "think" having lower ratio in the rear and higher ratio in the front reduces stresses on the gearbox gears, output shaft, drive shaft, and lesser extent the pinion gear. If the bulk of your torque multiplication is occurring in the rear end instead of the gearbox the stresses on everything between the gear and ring gear is lessened.
I know I have never seen anything advertised as a rally gearbox with a first gear lower (numerically larger) than 2.4-2.5 or so. Not that that means anything...

That theory works for some applications but for example on a fwd, the shorter ratio ring and pinions get much weaker the higher the number gets. The pinion becomes too small and the teeth tend to break easier. But anyways, dogbox is a rally specific gearbox and has a 2.636 1st gear, and 1:1 6th with a 4.9 CWP. And of course the Evo and STI gearboxes have a 3.0 1st and 3.3 respectively. And the Super1600 cars were around 3.5 to 3.6 first gear and 3.9 to 4.7 CWP. But since this a RWD application, it is true to see more boxes setup between 2.4 and 1:1 with a CWP in the 5.1 range. Mucho spesive setups though.

Lower gears are a higher ratio.

There's a big benefit, for solid axle cars, for putting most of the gear reduction in the rearend. Less torque on the driveshaft means the axle stays flatter instead of trying to pick one tire up. Easier on diffs, and handling stays more consistent left vs. right.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

True to that but that's normally only seen on drag cars with serious power, luckily in rally we can do well with dogshit for horsepower.