Ohlins -Mi01S1 (spring length)

[rackhenry]

So first a thank you to fe1rx and spidertri for the great writeup and analysis of the Ohlins and other great informative posts. Absolutely saved me tons of time! With that said my observations and some questions.

Context- 128i Track car build

Assumptions/conclusions - hope to confirm.

It would appear even with the new kit in order to run for example Apex 17x8.5 40 offset wheel with 235 tire (100 or 200 track tire) I still have to switch to a 7 inch spring for the front struts.

It would also appear in order to get the most clearance from wheel/tire to strut and spring perches, I would need to use the shock spacers fe1rx has developed. I am referring to the spacer on the shock tube, not the wheel spacer. Are these available from fe1rx?

Thanks again.

[spidertri]

Running a 17x8.5 et40 with a 235 shouldn't require any special parts for the ohlins. I ran 17x8.5 et40 with 245 initially and all I had to do was roll the rear fenders. I use those same wheels now as my street wheels w/ 225 tire and I just bolt them on and go between events.

When I moved to 17x9 et52 and a 255 tire, I needed a 15mm spacer in the front and 6in spring on the ohlins. The strut spacer from fe1rx just gave me the ride height that I wanted, and also increased clearance to the 255 tire.

[tracer bullet]

Originally Posted by rackhenry

7 inch spring

Keep in mind that spring rate is a factor with spring length. A stiff spring and a softer spring can be different lengths and ultimately give the same "height" since the car will compress them different amounts. You might need to also say what springs you plan to run.

[ShocknAwe]

Can you switch to the F8x front spindle and then use E9xM3 front dampers? They have an independent height adjuster allowing you to set height and preload separately and maximize clearance.

[rackhenry]

Originally Posted by spidertri

Running a 17x8.5 et40 with a 235 shouldn't require any special parts for the ohlins. I ran 17x8.5 et40 with 245 initially and all I had to do was roll the rear fenders. I use those same wheels now as my street wheels w/ 225 tire and I just bolt them on and go between events.

When I moved to 17x9 et52 and a 255 tire, I needed a 15mm spacer in the front and 6in spring on the ohlins. The strut spacer from fe1rx just gave me the ride height that I wanted, and also increased clearance to the 255 tire.

Thanks much for the fyi

[rackhenry]

Originally Posted by tracer bullet

Keep in mind that spring rate is a factor with spring length. A stiff spring and a softer spring can be different lengths and ultimately give the same "height" since the car will compress them different amounts. You might need to also say what springs you plan to run.

For the fronts swift Z65-228-070

[rackhenry]

Originally Posted by ShocknAwe

Can you switch to the F8x front spindle and then use E9xM3 front dampers? They have an independent height adjuster allowing you to set height and preload separately and maximize clearance.

I researched this and it is a very high level of effort which I am not sure would meet my objectives for the car etc. Thank you for the input as always!

[ShocknAwe]

Originally Posted by rackhenry

I researched this and it is a very high level of effort which I am not sure would meet my objectives for the car etc. Thank you for the input as always!

Same hub brakes etc bolt up and no custom arms required.

I did use an adapter caliper bracket to use the front rotor from the E46M3CSL, but otherwise it's all E82/1M stuff.

[135i_Life]

What is the benefit to using the F8X knuckle instead of the 1M/M3 version? Does the F8X use the same offset wheel as the 135i? I've done a rear conversion and will be doing a front at some point.

[ShocknAwe]

Originally Posted by 135i_Life

What is the benefit to using the F8X knuckle instead of the 1M/M3 version? Does the F8X use the same offset wheel as the 135i? I've done a rear conversion and will be doing a front at some point.

F8x offers a bit more static camber so don't need adjustable plates necessarily. If I recall it's also lighter and accepts E82 brakes.

[tracer bullet]

Originally Posted by ShocknAwe

... don't need adjustable plates necessarily...

I haven't changed this on my 1-er but I do know from past cars that avoiding this would be very nice indeed. The additional height added, the noise potential, and so on.

[rackhenry]

Originally Posted by ShocknAwe

Same hub brakes etc bolt up and no custom arms required.

I did use an adapter caliper bracket to use the front rotor from the E46M3CSL, but otherwise it's all E82/1M stuff.

Hi Shock, I read your build thread man! pretty cool build!

[ShocknAwe]

Originally Posted by tracer bullet

I haven't changed this on my 1-er but I do know from past cars that avoiding this would be very nice indeed. The additional height added, the noise potential, and so on.

Yep. M Camber arms M uprights slightly lowered and dinan fixed plates can get you to -3deg. No need for a adjustable plate that limits your alignment shop options and will require additional maintenance.

[rackhenry]

Originally Posted by ShocknAwe

Same hub brakes etc bolt up and no custom arms required.

I did use an adapter caliper bracket to use the front rotor from the E46M3CSL, but otherwise it's all E82/1M stuff.

I ready your build thread btw, nice build! Regarding the F8X spindles, so you can run standard E82 128/135 offset wheels, and the only change is the caliper and bracket.

Questions, when I looked up the price of the E46M3 CSL rotors they were 1k or so. Given its a track car, that's a consideration as I treat rotors as consumable items. Is there a less expensive place to source them or other brake rotor and caliper options? I really do like the idea of the F8X uprights vs camber plates if not needed.

[HP Autosport]

Originally Posted by rackhenry

For the fronts swift Z65-228-070

That is way too long of a spring for the front of the vehicle. You will need 203 or 178 depending your wheel/tire combo.

[rackhenry]

Originally Posted by HP Autosport

That is way too long of a spring for the front of the vehicle. You will need 203 or 178 depending your wheel/tire combo.

Thanks Harold, (bad copy paste). I have determined that I need the 7 inch for the front . Will reach out when I am going to order the springs.

[HP Autosport]

Originally Posted by rackhenry

Thanks Harold, (bad copy paste). I have determined that I need the 7 inch for the front . Will reach out when I am going to order the springs.

7" is 178 in Swift. That will get you the max wheel/tire clearance.