The death and rebirth of a DSP E46 330Ci - Page 4

wdc330i · 04-13-2016, 10:14 AM

Wow. Very impressive, John. You've earned that snazzy new garage setup you have.

Alan · 04-13-2016, 08:58 PM

One hell of a story ... Awesome

John V · 04-19-2016, 09:28 AM

The local autocross club had a practice event this weekend. I showed up expecting to shake down the car after all the offseason changes, and not really beat on the car too badly. After a couple of tentative runs by my co-driver and I it seemed like we weren't having any major tire-to-body contact issues and the car felt pretty good, so we pushed it.

Surprisingly, we didn't have to make any major changes to the setup. With the new differential and tires the car was much more predictable than it ever had been. Previously, the car was very loose on-power. I attributed this behavior to not having enough preload in the differential (i.e. it wouldn't lock up hard enough on acceleration), allowing too much wheel speed difference from left to right. With the new diff, the car will rotate on-throttle after turn-in, but it was very stable after that.

Maybe a little too stable. We were fighting a push most of the morning, but got the okay from the club to take some more runs in the afternoon so I made a front sway bar change (moved it one hole softer) and added a little bit of rear damping to get the car to be more lively, in particular on corner exit. It helped and I went about 0.5s faster on a 60 second course. This ended up being my fastest run, which was the fastest time of the day for the event:

https://youtu.be/llVMOHAnsPM

The car is slightly transitionally loose but it's still pushy steady-state. This local site is extremely bumpy and also pretty slick, and if it's pushy here it's going to be really pushy on a high-grip surface. So I'm going to add a little bit more rear wheel rate (spring) and reduce the rear toe-in which will loosen the car up everywhere, then take out some of the rear damping to make it more behaved transitionally without affecting steady-state.

First national event is in Ohio in three weeks but the car feels surprisingly well dialed in. There were a couple national champions running Z06 Corvettes this weekend at our local event and I was able to eclipse both of them which is something that's never happened before in this car, so the pace is there. This is going to be an exciting year if the car holds together.

bren · 04-19-2016, 10:05 AM

Quote:

Originally Posted by John V

First national event is in Ohio in three weeks but the car feels surprisingly well dialed in. There were a couple national champions running Z06 Corvettes this weekend at our local event and I was able to eclipse both of them which is something that's never happened before in this car, so the pace is there. This is going to be an exciting year if the car holds together.

Checking results....

Nicely done.

Biggins · 04-19-2016, 10:22 AM

It looked and sounded amazing, and the times back it up! It did appear that the rears might have been rubbing when Sam? was taking some runs in Heat 3 of morning? It didn't look major from my work station, but there was definitely a little smoke.

We were running in the same morning session, but it looked like Kevin got up to speed quickly too.

John V · 04-19-2016, 10:58 AM

Kevin is quick, always has been, his car held him back.

Oh, the rear tires were definitely rubbing. To get 315s to fit under the car you have to get the offset just perfect and I played it a little too close. It was very minor rubbing of the inner rear sidewall against the inner wheelhouse. I can't legally clearance the wheelhouse (though I know people do it) so I just need to run a slightly thicker spacer.

We have Solostorm data showing that my car can now accelerate out of corners at the same longitudinal g's as his car (at FedEx at least). That was not expected by either of us and is a big change from last year.

John V · 04-19-2016, 11:09 AM

Quote:

Originally Posted by bren

Checking results....

Nicely done.

Hey, are you coming out this year or taking a year off? I can't remember if you sold the Z06 or not.

bren · 04-19-2016, 11:49 AM

Quote:

Originally Posted by John V

Hey, are you coming out this year or taking a year off? I can't remember if you sold the Z06 or not.

I still have it. I think I decided to keep it another year.

I'm registered for Wilmington and DC Pros, and I'll probably run FedEx on Saturday - though I guess I should register for that soon.

*clyde* · 04-19-2016, 06:16 PM

Quote:

Originally Posted by bren

I still have it. I think I decided to keep it another year.

I'm registered for Wilmington and DC Pros, and I'll probably run FedEx on Saturday - though I guess I should register for that soon.

Yeah, I finally did that today.

*clyde* · 04-19-2016, 06:17 PM

Quote:

Originally Posted by John V

The local autocross club had a practice event this weekend. I showed up expecting to shake down the car after all the offseason changes, and not really beat on the car too badly. After a couple of tentative runs by my co-driver and I it seemed like we weren't having any major tire-to-body contact issues and the car felt pretty good, so we pushed it.

Surprisingly, we didn't have to make any major changes to the setup. With the new differential and tires the car was much more predictable than it ever had been. Previously, the car was very loose on-power. I attributed this behavior to not having enough preload in the differential (i.e. it wouldn't lock up hard enough on acceleration), allowing too much wheel speed difference from left to right. With the new diff, the car will rotate on-throttle after turn-in, but it was very stable after that.

Maybe a little too stable. We were fighting a push most of the morning, but got the okay from the club to take some more runs in the afternoon so I made a front sway bar change (moved it one hole softer) and added a little bit of rear damping to get the car to be more lively, in particular on corner exit. It helped and I went about 0.5s faster on a 60 second course. This ended up being my fastest run, which was the fastest time of the day for the event:

https://youtu.be/llVMOHAnsPM

The car is slightly transitionally loose but it's still pushy steady-state. This local site is extremely bumpy and also pretty slick, and if it's pushy here it's going to be really pushy on a high-grip surface. So I'm going to add a little bit more rear wheel rate (spring) and reduce the rear toe-in which will loosen the car up everywhere, then take out some of the rear damping to make it more behaved transitionally without affecting steady-state.

First national event is in Ohio in three weeks but the car feels surprisingly well dialed in. There were a couple national champions running Z06 Corvettes this weekend at our local event and I was able to eclipse both of them which is something that's never happened before in this car, so the pace is there. This is going to be an exciting year if the car holds together.

I like how you refer to "the club" like it's a faceless overlord.

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04-19-2016, 09:28 AM	#33
John V No more BMWs Join Date: Apr 2005 Carmudgeonly Ride: Ram, MS3, CX-5, RX-8 Location: Glenwood, MD Posts: 14,753	The local autocross club had a practice event this weekend. I showed up expecting to shake down the car after all the offseason changes, and not really beat on the car too badly. After a couple of tentative runs by my co-driver and I it seemed like we weren't having any major tire-to-body contact issues and the car felt pretty good, so we pushed it. Surprisingly, we didn't have to make any major changes to the setup. With the new differential and tires the car was much more predictable than it ever had been. Previously, the car was very loose on-power. I attributed this behavior to not having enough preload in the differential (i.e. it wouldn't lock up hard enough on acceleration), allowing too much wheel speed difference from left to right. With the new diff, the car will rotate on-throttle after turn-in, but it was very stable after that. Maybe a little too stable. We were fighting a push most of the morning, but got the okay from the club to take some more runs in the afternoon so I made a front sway bar change (moved it one hole softer) and added a little bit of rear damping to get the car to be more lively, in particular on corner exit. It helped and I went about 0.5s faster on a 60 second course. This ended up being my fastest run, which was the fastest time of the day for the event: https://youtu.be/llVMOHAnsPM The car is slightly transitionally loose but it's still pushy steady-state. This local site is extremely bumpy and also pretty slick, and if it's pushy here it's going to be really pushy on a high-grip surface. So I'm going to add a little bit more rear wheel rate (spring) and reduce the rear toe-in which will loosen the car up everywhere, then take out some of the rear damping to make it more behaved transitionally without affecting steady-state. First national event is in Ohio in three weeks but the car feels surprisingly well dialed in. There were a couple national champions running Z06 Corvettes this weekend at our local event and I was able to eclipse both of them which is something that's never happened before in this car, so the pace is there. This is going to be an exciting year if the car holds together.

04-19-2016, 10:22 AM	#35
Biggins Crotchety Join Date: Aug 2007 Carmudgeonly Ride: 22 Tiguan, 11 328i Posts: 912	It looked and sounded amazing, and the times back it up! It did appear that the rears might have been rubbing when Sam? was taking some runs in Heat 3 of morning? It didn't look major from my work station, but there was definitely a little smoke. We were running in the same morning session, but it looked like Kevin got up to speed quickly too.

04-19-2016, 10:58 AM	#36
John V No more BMWs Join Date: Apr 2005 Carmudgeonly Ride: Ram, MS3, CX-5, RX-8 Location: Glenwood, MD Posts: 14,753	Kevin is quick, always has been, his car held him back. Oh, the rear tires were definitely rubbing. To get 315s to fit under the car you have to get the offset just perfect and I played it a little too close. It was very minor rubbing of the inner rear sidewall against the inner wheelhouse. I can't legally clearance the wheelhouse (though I know people do it) so I just need to run a slightly thicker spacer. We have Solostorm data showing that my car can now accelerate out of corners at the same longitudinal g's as his car (at FedEx at least). That was not expected by either of us and is a big change from last year.