Official 135i/128i SCCA FS/STU/STX Chat thread

[Kgolf31]

Originally Posted by Ginger_Extract

It's a 1-Series, apparently understeer is impossible to eliminate...for reasons...? I even watered the front tires down and everything.

Yes it is, we run the ProSolo here.

A sweeper, yes. A slalom....no

Shock settings, bar settings, driving style, alignment etc etc can all effect this. It's really a balancing act but I've had no push issues on the most grip sites in the US

[YarkoDrives]

speaking of oversteer.. here's my first run from Day1 of SCCA TireRack Rocky Mountain Champ Tour.

I did not get any more videos that day, but I did manage to tame the oversteer and end up in third place.

[fcman]

Originally Posted by YarkoDrives

speaking of oversteer.. here's my first run from Day1 of SCCA TireRack Rocky Mountain Champ Tour.
I did not get any more videos that day, but I did manage to tame the oversteer and end up in third place.

I watched a black 135i do the same thing at a local autox, although he ended up going rear first into a metal stairway... ouch

[lowside67]

Originally Posted by Ginger_Extract

It's a 1-Series, apparently understeer is impossible to eliminate...for reasons...? I even watered the front tires down and everything.

I think that's only true to an extent. A Macstrut car is never going to have that ability to be softly sprung and just turn in like a double wishbone car, but that's a long way from having chronic, incurable understeer.

The nice thing is that we can learn a lot from the chassis before the 1 series - specifically the E36 and E46 as the front ends are so similar in design. In stock format those cars are terrible for understeer but well prepared they can be tremendously satisfying and responsive.

My E36 at least always "felt" like it was understeering, even on a square 285 Hoosier setup with 3.5 degrees of front camber, but it was extremely quick and competitive, it just required a certain style of driving which was slower and more calculated entries combined with early throttle application.

I know how tailhappy the 135 is and how it probably doesn't seem to fit my criteria of a chassis being good at putting power down, but I think that's largely differential choice. Most of us who are building dual duty track and street cars rightly lean towards helical LSDs for their no maintenance and fantastic street behaviour, but somewhat ignore the rather large performance gap they give up over a clutch type. This is of course magnified with a modified 135 trying to put power down on street tires in an autocross setting - basically a diff's "worst case scenario."

I suspect if you had a clutch type diff and consciously tried a few different driving styles, I suspect the car might impress you dramatically.

Mark

[Ginger_Extract]

Originally Posted by lowside67

I think that's only true to an extent. A Macstrut car is never going to have that ability to be softly sprung and just turn in like a double wishbone car, but that's a long way from having chronic, incurable understeer.

The nice thing is that we can learn a lot from the chassis before the 1 series - specifically the E36 and E46 as the front ends are so similar in design. In stock format those cars are terrible for understeer but well prepared they can be tremendously satisfying and responsive.

My E36 at least always "felt" like it was understeering, even on a square 285 Hoosier setup with 3.5 degrees of front camber, but it was extremely quick and competitive, it just required a certain style of driving which was slower and more calculated entries combined with early throttle application.

I know how tailhappy the 135 is and how it probably doesn't seem to fit my criteria of a chassis being good at putting power down, but I think that's largely differential choice. Most of us who are building dual duty track and street cars rightly lean towards helical LSDs for their no maintenance and fantastic street behaviour, but somewhat ignore the rather large performance gap they give up over a clutch type. This is of course magnified with a modified 135 trying to put power down on street tires in an autocross setting - basically a diff's "worst case scenario."

I suspect if you had a clutch type diff and consciously tried a few different driving styles, I suspect the car might impress you dramatically.

Mark

Interesting. I actually steered away from a clutch type diff because of the corner entry understeer issues that I have with the car. If I could stuff a ton of rubber under the front end, and get as much camber as the E36/E46, that would be great, but with the narrow body, it just isn't happening.
With that said, a lot of the way I have built my car up is based on E36/E46 cars, i.e. max negative camber up front with a big bar, F/R spring rate bias, chosen performance brands etc.

[lowside67]

I should have specified, a ramped clutch type. I went from a "standard" 3.15 M3 LSD to a fairly $$ built ramped style in my E36 and the turn in off of power was truly night and day. I was sweating and chewing my nails after I ordered the diff before I had received it as it was an expensive purchase and after exactly 1 autocross, I never questioned it again.

I don't think "transformed" is even a strong enough word - the difference was that big. You could really feel the effects of the ramp in steady state cornering - apply throttle, feel the back lock and start slowly pushing as the back grips, breathe off the throttle, feel the back go open and the nose just tucks right back in.

I haven't figured out who will build it yet, but I consider a good clutch type an absolute must in my build. I suspect Kyle will chime in with some similar feedback as I know he's got a ramped clutch type as well and I think his awesome results have spoken for themself as to how well the package is working.

Mark

[Kgolf31]

Originally Posted by lowside67

I haven't figured out who will build it yet, but I consider a good clutch type an absolute must in my build. I suspect Kyle will chime in with some similar feedback as I know he's got a ramped clutch type as well and I think his awesome results have spoken for themself as to how well the package is working.

Mark

Yea, my diff is absolutely unreal. I've seen a minor increase in some push due to static lock but nothing some shock changes couldn't fix.

However, in the wet this car is absolutely stupid. Get on the gas and it just sucks the corner.

[Kgolf31]

Toledo Pro Tune-In Write-Up:

This weekend!

http://solomatters.com/tune-in_2015_...toledo_prosolo

[Kgolf31]

Events Supps for this weekend are up for those who are interested.

I run Shift B, Group 4!

[Ginger_Extract]

Good luck, Kyle.

Well Gang, I had a D.E. planned for this Saturday, but my passenger front brake caliper blew out (one piston, two seals). I sourced a rebuild kit from RacingBrake but I don't know if I can rebuild the calipers and get the car ready in time for the event.

[Kgolf31]

So weekend didn't turn out to be the greatest.

Saturday was SOAKING wet. Ended up getting around 3 inches of total rain. So much rain afternoon runs were cancelled.

Video of my fastest raw time runs, but still was P1 Saturday. The car was throwing down pretty close to the fastest raw times of the whole day, against 250 cars. The wet setup is pretty unreal.

Today was met with dry conditions. Today wasn't so epic. Apparently you need to be clean to actually have a chance at doing well. I didn't do that. Sat on my first left and a had to pull a parachute run on my last right. Rest coned away, majority of them minor hits over bases which barely knocked the cone off.

Car had the raw times to place within a tenth of 1st.
Better to know the car has the potential to place well, just need to put those runs together next time.


4th out of 13 in STX is nothing to dismiss, just sucks knowing the car had more in it if the runs were clean throughout.

I'll get video up soon. I have a feeling completely fresh RE-71Rs we had some loss of feeling in the tires, especially sweepers that may have through our setup off.

Standings here:

http://sololive.scca.com/PS/STX.html

[Kgolf31]

"Fastest" runs from this weekend. Ugh left side is absolutely horrible.

[dtla1]

So checking in about the 17X9 ET45 mentioned earlier running a 255. Is the fitment in the rear really not possible without fender modification? I'd really like to get that recommendation money to Kgolf31 for buying these..

[Kgolf31]

Originally Posted by dtla1

So checking in about the 17X9 ET45 mentioned earlier running a 255. Is the fitment in the rear really not possible without fender modification? I'd really like to get that recommendation money to Kgolf31 for buying these..

You'll need a lot of camber

[Ginger_Extract]

Originally Posted by dtla1

So checking in about the 17X9 ET45 mentioned earlier running a 255. Is the fitment in the rear really not possible without fender modification? I'd really like to get that recommendation money to Kgolf31 for buying these..

If you don't roll the rears, I would guess that you'll need at least -3* camber in the rear to clear it.

[dtla1]

Hmmm, I'm currently at -2.2* in the rear. Maybe I'll just stick to my 261m, but those are so much lighter, and 17!! Damn

[Kgolf31]

Car is officially dedicated to AutoX

All stickered up:

[Kgolf31]

Scales at Toledo MT

[Ginger_Extract]

That's with you in the car???

[Kgolf31]

Originally Posted by Ginger_Extract

That's with you in the car???

No, me outside

[Kgolf31]

P1

[Kgolf31]

Fastest run from this weekend. Peaked at 1.45 lateral Gs. LOL