Nationals Report in Sportscar

[mwizard]

Interesting info in the CM article. Supposedly Nick made 13 shifts on the East Course(for the win). We made 4, including into 4th(for the sweeper at "Die Another Day") and back to 3rd. I much prefer my setup, a lot less busy. Now I just need to figure out how to be faster
Looking forward to next year.
Mark

[mwizard]

Here is more info to consider. The top part of the spread sheet is my setup.
Mark

[Jim Garry]

Regarding the "desired" gearing ... first gear ratio will not get you off the line well. Also, since it is not a fixed gear, it will break.

Not arguing, but if I had the choice between the two options I'd go with the current set up.

[Daryl DeArman]

Is it common in solo2 to have 2nd and 3rd effectively the same ratio so that you have 3 usable gears but most shifts are the 3-4 gate only?

[Jim Garry]

The "desired" 2nd and 3rd don't seem logical. Looking at the spreadsheet, it would seem apparent that Mark input the wrong gear for 2nd because no one would set up their gearbox to jump from 55 mph to 88 mph.

But for Solo the top speed in the "desired" section is not necessary.



Daryl, just an fyi ... SCCA no longer refers to autocrossing as "Solo II". It's just "Solo". The reason is because what used to be called "Solo I" (time trials, hill climbs, etc), were transferred to the Club Racing program some years ago.

[Dick R.]

Mark,

You probably should try to get the car owner (Chris Pruett) or Nick to comment about the pros and cons of the gearing in Chris's car and why Nick decided to shift so much. Maybe one of the other Midwest guys will comment on one of the other common gearing choices they use.

Nick and other's have shared this info with me but I'm not going to "blab" without their OK which means it would be much better coming directly than relying on my interpretation.

Too bad I'm such a bad 2-3 shifter.

Dick

[Barry Ott]

My gearing is pretty close to Marks "Current". I know my 1st is the same, pretty sure 2nd is the same, but my 3rd and 4th are a little taller (seems like 74 and 87, I'll check).

I think we shifted 14 times, essentially used 2nd for all the "pin" turns and up to 3rd between them. The two exceptions are that we didn't need 3rd for the tight slalom (Shaken, not stirred) and we left it in 3rd for the the last pin turn before the finish (View to a kill). I'll probably leave the gearing where it's at, but I've contemplated a little taller 2nd and 3rd.....

Barry

[-pru-]

Mark,

You probably should try to get the car owner (Chris Pruett) or Nick to comment about the pros and cons of the gearing in Chris's car and why Nick decided to shift so much. Maybe one of the other Midwest guys will comment on one of the other common gearing choices they use.

Nick and other's have shared this info with me but I'm not going to "blab" without their OK which means it would be much better coming directly than relying on my interpretation.

Too bad I'm such a bad 2-3 shifter.

Dick

Here's an entire thread on gearing : CM Lincoln Gearing/Speed Range?

Since my post in the above thread, I have changed my R&P to a 9:31 and run the following gears :

1 - 13:38 (45 mph)
2 - 16:35 (60 mph)
3 - 18:32 (75 mph)
4 - 20:30 (90 mph)

All the above MPH are at a ~6800 shift point.

Take care,

[-pru-]

I think we shifted 14 times, essentially used 2nd for all the "pin" turns and up to 3rd between them.

As was the case for Nick and I which supports the 13 number noted in Sportscar.

[Dick R.]

As was the case for Nick and I which supports the 13 number noted in Sportscar.

Chris and Barry,

If you were running a roughly 66 - 68 mph third gear and a roughly 78 or so 4th do you think you would have shifted up or down from that gear as much as you did between your second and third? Especially Chris with the Kent's higher rev limit compared to the Honda so "running out of gear" was less likely?

Thanks,

Dick

[Dick R.]

How many of you guys up shift when cornering at over 1g?

Look at this data "picture" and at the video with data displayed (ignore the "gear") The whole run was in my 66 mph second except for after the walloms near the finish . . . couldn't find a safe place to up shift. See the vertical g spike just after the selected point in the picture. That bump scared me from shifting to third for the finish corner/wallom segment.

http://www.youtube.com/watch?v=wHc5G...L3OwPSKh6-M9-w

[Dick R.]

Here is the first day. No real need to up shift from the 66 mph gear. Similar issue though of where would I if the ratio didn't cover the whole run?

http://www.youtube.com/watch?v=V6i4N...L3OwPSKh6-M9-w

[george schilling]

Since my post in the above thread, I have changed my R&P to a 9:31 and run the following gears :

1 - 13:38 (45 mph)
2 - 16:35 (60 mph)
3 - 18:32 (75 mph)
4 - 20:30 (90 mph)

All the above MPH are at a ~6800 shift point.

Take care,

Well, there goes our gearing excuse. LOL

Nick looked noticeably faster than Joey in the big left hand sweeper that was highlighted at the beginning of the east course. We were in 3rd at that point with identical gearing as you. We shifted into 3rd early to avoid a shift in the sweeper and carried third to the right hander in the NE corner. Did you guys do likewise?

FYI, my 3rd and fourth are identical to yours Pru. My first and second are slightly shorter at 12:38 and 16:36.

[-pru-]

If you were running a roughly 66 - 68 mph third gear and a roughly 78 or so 4th do you think you would have shifted up or down from that gear as much as you did between your second and third?

Nick looked noticeably faster than Joey in the big left hand sweeper that was highlighted at the beginning of the east course. We were in 3rd at that point with identical gearing as you. We shifted into 3rd early to avoid a shift in the sweeper and carried third to the right hander in the NE corner. Did you guys do likewise?.

All,

Hopefully this will answer a few question : 13-0906 Linclon East Nick R3

Angle of camera is such that you can see most of the shifts.

Take care,

[mwizard]

All,

Hopefully this will answer a few question : 13-0906 Linclon East Nick R3

Angle of camera is such that you can see most of the shifts.

Take care,

Great memories of the event watching the video. As I think back, I should have downshifted to 2nd for the turn before the slalom and through it. Other than that I am happy with my 4 gear set up. Now I just have to prove it works by beating you guys next year
I need to work on the 3-2 shifts so that I don't avoid them.
Mark

[Barry Ott]

Chris and Barry,

If you were running a roughly 66 - 68 mph third gear and a roughly 78 or so 4th do you think you would have shifted up or down from that gear as much as you did between your second and third? Especially Chris with the Kent's higher rev limit compared to the Honda so "running out of gear" was less likely?

Thanks,

Dick

I suspect we would have been on a limiter at 67 a few times. I'd guess that it would have saved a couple 2-3 (and associated 3-2) shifts but not eliminated all of them. Note that we pulled out of those turns nicely with gearing we had :-) The West course could be a different story, 67 or so might have been really good. Might, dunno for sure.

Barry

[Locked]

It's really hard to say for sure..

I made shifts to get to 3rd gear on the west course and didnt make another shift. I remember telling pru that the car felt under powered. Really, saying the car was hooked up after the 1st run. But after being off of Brandons leading time I was blaming gearing. Reviewing data with Don showed that i averaged 1200 rpm less, and could have done the whole course in 2nd.. A significant amount of hp, but the mph curves didnt seem to support a lack of power. Rather, It showed 2 mistakes in my driving..

Walking the east course reminded me of the milwaukee tour, a course where i was afraid to do 3 downshift for fear of missing them. I was determined that i had to make those shifts because the data supported that i should have been doing them in milwaukee.

My vd(Brandon's) was setup to use 4 gears. Imo, that was the better setup for the west. I liked the 3 gears with the downshifts on the east. As i didnt have to make an upshift in the high speed hairy elements. Whats interesting is that reviewing the east data the speeds in those pins were quite higher than what we saw in milwaukee. I could argue that I only needed to be in 2nd for the tighter slalom that Barry referred to.

[Dick R.]

OK.

For those of you who have broken 16 tooth seconds (Nick, Jim, ???) what strength version, age, and brand were they? Specifically were they the post 1993 Hewland or Webster with the best materials per this thread? http://apexspeed.com/forums/showthre...=gear+strength

I own a 16 W 35 dated 07 90 and a 16 M 36 S dated about 09 93. Both have very little use.

Should I spend a couple hundred dollars for a new Webster with the best material or can I "trust" one of the older versions for autox no clutch shifting, frequently from 1st to 2nd for "Pro Solo" type straight line starts where the engine will be at over 6500 rpm when the gear is engaged and the rpm will be "dragged down" by the clutch.

Data analysis shows some scary stuff see the attached screen capture of a typical 1 - 2 shift in a Pro Solo. For scale each column is 0.2 seconds. The throttle lift time is 0.2 seconds but rpm doesn't match gearing until 0.6 seconds after full throttle which means the gear has been engaged "slightly" longer. Tilton clutch.

[Jim Garry]

My car experienced two broken 16 tooth gears. Both occurred while a co-driver was behind the wheel. I tend to think that was coincidence but he could have been less mechanically sympathetic. I do not know.

Also unknown is what year or designation those gears were. Those breakages occurred in the early 2000s.

After that I had my gears treated by Taylor with REM Isotropic Finishing. I'm not trying to sell this. Just saying I never broke a gear again. But that could have been because by then I had run out of my collection of older 16-tooth gears and had to purchase new. :-)

I forget how much the treatment cost but I vaguely recall that the cost was reasonable. Given that both of those breakages occurred at Tour events, it seemed like a reasonable cost to keep it from happening again.

[Daryl DeArman]

Data analysis shows some scary stuff see the attached screen capture of a typical 1 - 2 shift in a Pro Solo. For scale each column is 0.2 seconds. The throttle lift time is 0.2 seconds but rpm doesn't match gearing until 0.6 seconds after full throttle which means the gear has been engaged "slightly" longer. Tilton clutch.

Seems to me that is a slight % clutch slipping...what am I missing?

BTW, what DAQ system and software are you using?

[Dick R.]

Seems to me that is a slight % clutch slipping...what am I missing?

BTW, what DAQ system and software are you using?

Daryl - I'm not sure what you mean by slight %. I assume that with fast no clutch shift that the clutch has to slip and/or the tires have to spin slightly to bring the revs down for the taller gear. I was mostly just showing what appears to be "significant" loading on the gear with a shift like this. Note the brief jump in wheel speed also.

DA is a Race Technology DL1 and their Analysis software version 8.5. The video in the earlier posts is from the RT Video4 mounted to the "vibrates like crazy" main roll hoop on my 85 VD.

Dick
CM 85
85 VD

[Dick R.]

Jim - Thanks for the REM treatment suggestion!

Dick

[Daryl DeArman]

I assume that with fast no clutch shift that the clutch has to slip and/or the tires have to spin slightly to bring the revs down for the taller gear. I was mostly just showing what appears to be "significant" loading on the gear with a shift like this. Note the brief jump in wheel speed also.

Agreed. I was confused by what you meant by the gear being enganged longer. Looking at the data I just saw a certain percentage of clutch slippage (engine RPM vs. trans input shaft speed)

The clutch and/or tires have to give some until the engine rpms in the new gear match the road speed....how long should that take? Is .6 too long (too much clutch slippage after tire quit spinning), would .2 be too much shock on the gears? Clearly at the instant the shift was completed the tire contact patch was the weak-link, after that the clutch became the weak-link.