The Drivers Edge weekend at MSR-Houston review or; I have a lot to learn

Strengthrehab

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If fifth is 1:1 on your car, and with a 7000RPM rev limit, I can't for the life of me see the need for 6th gear, unless you are SERIOUSLY hauling the mail, and then only on the big end of very few straights in this country...

There are lots of transmission calculators, and if you plug in your gear, trans ratios, tire size and 3500 and 7000 RPM points, you can get a solid idea of min and max speed in each gear. With a 3650 (or a T56), virtually all the tracks in the midwest can be run in 3rd and 4th (which is 1:1). 2nd is rare, and higher than 4th only on two tracks that I can think of... Road America and Mid-Ohio, both of which have some pretty high-speed straights. Like 140mph+ in a stock-ish power level car.

I think you're right in that you're shifting too often. NOT a slam, but constructive criticism to help confirm your suspicion. Also, one failing I see fairly regularly on the downshifts is people trying to get it done too soon in the braking zone. They tend to get the downshift in early, and it's MUCH harder to rev-match with a gear-engagement of 5000+RPM than it is to just wait a tick and do the match at 4000, or whatever. After all, the goal here is to be all done with the shifting and have the clutch out in the correct gear just prior to turn-in. If you find yourself finishing the rev-match, and still dropping more than 6-700rpm under braking, you're downshifting too early. The vast majority of corners only require changing down one gear. A small handful will require dropping two gears. Only a select few will require dropping down three or more.

The MT82 2/3/4/5 ratios are 2.43/1.69/1.32/1.00, and sixth is an unsusable 0.65:1 overdrive. my TR3650, by comparison has 2/3/4 ratios of 2.00/1.32/1.00, so our last two usable gears are identical, but you have a nice "intermediate gear" 3rd, where the 3650's 2nd might be a bit too aggressive by comparison.

Most corners have an entry speed between 45 and 65 mph, and I think we can all agree that we don't really want to up-shift until we hit track-out and aren't relying on the weight transfer from acceleration to plant the back end so much... Think about your "speed in gear" as you reach the track-out point at corner exit. With my TR-3650, 3rd (your fourth) is usable from 54mph up through 99mph, and 4th (your 5th) is good from 71mph up through 130mph. That's with a 6400rpm redline. If you extend the powerband up to 7000, though, that makes the max speeds 108 and 142mph. Assuming 3.73 gears, and 25.5" tires (275/35-18).
Given all that, how many corners do you see where your EXIT speed is below 54mph? Not many. That's how many corners you'd need to use 3rd gear for. So, let's assume, for now, that you're only going to be needing 4th and 5th (1.32:1 and 1:1), so at most, you'll have a single downshift into any given corner. If your entry into the braking zone is under 108, you should be in 4th gear, no downshift required, just brake, turn, go! If you speed into the braking zone is 125mph, for example, and the entry speed is 50mph, you know that you'll need to drop to 4th gear, but you also need to shed the speed to get DOWN to 50. You could downshift as soon as you hit 108mph (top of 4th), but why bang the motor into the limiter just to change gears? Wait. Wait some more. You could also change around 80mph, roughly 4000 rpm in 5th gear, which will bump you up to around 5100-5200 in 4th on the switch. That doesn't sound too bad, now does it? Give it a quick 1500rpm blip, drop down the gear, and finish your braking. The point here is that to have a nice, easy downshift where you're not spinning the motor into the stratosphere, and with not a huge blip required, you just need to wait a while. It takes time to drop your speed from 125 down to 50, and all you're doing in there is braking in a straight line. You also leave yourself some room for error (decelerating from 80 down to 50) in case you miss the gear, or bobble the blip, or whatever. Plenty of time to recover before turn-in.

For now, I would just plan on using 4th and 5th, and then see if there is a corner or two that you're just lugging too badly before thinking about dropping down to 3rd. I would also avoid 6th like the plague, if you can. Again, unless and until your road-speed is north of 140mph, and you still have a ways to go before the braking zone, you won't gain anything by shifting up into an overdrive gear. Essentially, unless you're hitting redline (rev limiter or self-imposed point to keep temps down, or whatever), don't shift up. With a single-gear downshift, leave it for the last 1/3 of the braking zone.

A note on your instructor's note: He sounds like a really good instructor, sensitive to your experiences, supportive and constructive. He's also very wise, identifying that the student/teacher pairing has to have chemistry to work properly. If you worked well with him, then I think requesting him again would be a great idea!
Best post ever. Thank you. My rear tires now are 27.7 in (275/40/19). I was def going to look at a graph with the info uou posted so i could do what your post did.

Thanks a ton.

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ddd4114

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If fifth is 1:1 on your car, and with a 7000RPM rev limit, I can't for the life of me see the need for 6th gear, unless you are SERIOUSLY hauling the mail, and then only on the big end of very few straights in this country...

There are lots of transmission calculators, and if you plug in your gear, trans ratios, tire size and 3500 and 7000 RPM points, you can get a solid idea of min and max speed in each gear. With a 3650 (or a T56), virtually all the tracks in the midwest can be run in 3rd and 4th (which is 1:1). 2nd is rare, and higher than 4th only on two tracks that I can think of... Road America and Mid-Ohio, both of which have some pretty high-speed straights. Like 140mph+ in a stock-ish power level car.
Agreed.

To add to what Dave said - I've tried 3.73's, 3.55's, and 3.31's with an MT82 over the last few years, and the only track that's really needed 6th gear is Road America. With 3.31's, I can stay in 5th the whole time. This is with stock (Coyote) power, stock weight, decent suspension, and skinny Hoosiers. I never tried Hoosiers with 3.73's at Mid-Ohio, but with that combination, you might need to shift into 6th there. With 3.55's, I'm almost hitting the redline at the end of the back straight, but it might actually be worth riding the rev-limiter for a bit with 3.73's.

For the data nerds like me, here is a comparison between staying in 5th gear with 3:31's (in red) and shifting to 6th gear with 3.55's (in black):
6thGearAnalysis_zpsghp4vdvt.jpg


The top graph is speed, the middle is longitudinal acceleration, and the bottom graph is the time difference between the two laps. The large peak in the middle of the graph is the brake pedal switch.

Staying in 5th added 5 mph because the acceleration (middle graph) was much better with the engine closer to peak power. I forgot to put engine speed on the graph, but in 6th I was at ~4500 rpm before braking, and in 5th, I was at ~6500 rpm. Also, you can see there is a slight deceleration during the shift.

Despite that difference, I only saved ~0.1s by staying in 5th because I shifted into 6th ~700 feet before hitting the brakes. It sounds like a lot of distance, but at 140+ mph, a few hundred feet passes really fast. The other ~0.2s in the time difference graph were from braking a little later and improving my line a tad, so that's unrelated.

The exception for all of this is if you're really worried about your engine. For the reciprocating components, stress increases exponentially with engine speed. Shifting early will slow you down, but it might give you peace of mind if you don't care that much about lap times. You can be the judge of how much it matters. That being said, the Coyote is a fantastic engine, and it's pretty tough to damage unless you boost power by a lot. I haven't had a single issue in 5 years of tracking mine.
 

Voltwings

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Two things i would like to add. A lot of good information has been said here, but i am not going to quote anything in particular because of the length of some of them.

I would just like to add that while MSR-H is easier on the brakes than TWS, i would still recommend brake ducts. Its not terribly expensive or difficult to add, and is really just a good investment. I am still relatively "new" myself (Blue solo qualified with the driver's edge) but i know when i was still green as green could be i had a habit like many newbies of dragging the brakes instead of just a hard BRAKE right before the corner. I've been told more than once newbs are almost harder on the brakes than pros haha.

Also, at least for my 3.31 '13 i was able to do all of MSR-H in 3-4 gear. The car has enough torque and RPM to make due. The only spot i almost needed 5th was at the end of the pit straight assuming you were running CCW, but i could wind 4th out just enough to not need the shift. I also could have maybe been in 2nd for diamonds edge, but 3rd still had enough grunt and there's enough camber there with the right line to get around it in a hurry.

All in all just keep at it. Its a ton of fun and they really do run a fantastic program.
 

Strengthrehab

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Two things i would like to add. A lot of good information has been said here, but i am not going to quote anything in particular because of the length of some of them.

I would just like to add that while MSR-H is easier on the brakes than TWS, i would still recommend brake ducts. Its not terribly expensive or difficult to add, and is really just a good investment. I am still relatively "new" myself (Blue solo qualified with the driver's edge) but i know when i was still green as green could be i had a habit like many newbies of dragging the brakes instead of just a hard BRAKE right before the corner. I've been told more than once newbs are almost harder on the brakes than pros haha.

Also, at least for my 3.31 '13 i was able to do all of MSR-H in 3-4 gear. The car has enough torque and RPM to make due. The only spot i almost needed 5th was at the end of the pit straight assuming you were running CCW, but i could wind 4th out just enough to not need the shift. I also could have maybe been in 2nd for diamonds edge, but 3rd still had enough grunt and there's enough camber there with the right line to get around it in a hurry.

All in all just keep at it. Its a ton of fun and they really do run a fantastic program.
Werr yiu there this past weekend? I think i hit diamonds edge perfectly maybe 2 times all weekend. Hell going into the little turns before the launch i dropped to 2nd and was sloooooooow.

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Voltwings

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Werr yiu there this past weekend? I think i hit diamonds edge perfectly maybe 2 times all weekend. Hell going into the little turns before the launch i dropped to 2nd and was sloooooooow.

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I'm getting married in November, and the Mrs and i both track, so we're on an indefinite hiatus until we recover from the wedding haha. I'll be honest, we've been hitting TWS as much as we could since its apparently closed for good (for real this time?), but MSR-H will now be our home track, so hopefully we'll be out there more.
 

Strengthrehab

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Im on waitlist for msr-h in nov and plan to do tws in dec

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SoundGuyDave

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Trip-D; nice job bringing the data!! One comment I'll make, if I may: You had a +5mph delta going into the braking zone staying 1:1. That, to me is a telling point, and is backed up by my own data (lap and split times). Since you mentioned Road America, there are three points on that track where I need to make a shift/don't-shift decision going into the EPA-friendly overdrive. The pit straight leading into T1 is a no brainer. I have to get into 5th just past the flag stand, which is what, 1000' from the braking point? Between T3 and T5, and between The Kink and Canada Corner (T11-T12), though, I can run it either way. What I've found over hundreds of laps there at track days, Time Trial sessions, sprint races and enduros, is that if you go to OD, you lose about 0.2-0.5 seconds per lap. Some is lost in the actual shift, but the bulk is from the lack of gearing leverage to keep the car accelerating. In a sprint race or Time Trial session, I leave it in fourth and just bang it off the limiter for the few hundred feet to the braking zone, unless I just KILLED it on the previous corner exit. For track days or endurance racing, though, I tend to use OD to keep the revs down, and thus the heat and the fuel consumption. The exception is if I'm in an enduro and am in "attack mode," trying to make or defend a pass for strategic reasons.

Rehab: Congrats on the upcoming nuptuals!! The change in tire diameter will have a profound impact on the min and max speed points in gear, so definitely plot out where your powerband lands against the gearing available to see what that tells you. With the PP option, that gives you a 3.73 screw, right? Might just be the right rear gear for the big tracks, but may also be a bit short (numerically low) for the tighter club tracks. Or it might not! The numbers will tell all. In particular, pay attention to where the RPM falls on the upshift, to make sure that you're not going to be too far below where the torque comes in on your engine. Playing with different rear gear ratios and trans gear choices can be quite eye-opening. 3.31 in 2/3/4 vs. 3.73 in 3/4/5 for example, can give really different road-speed shift points.
 

Speedboosted

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I've made and studied much too many charts regarding gear ratio vs trans ratio vs tire size when trying to decide on rear gears for my car (3v with a 6060). The MT-82 is in my opinion the best trans gearing wise for road racing, as the 3/4/5 split is excellent with 3.31 gears.

One thing I'll add as well, this whole post that you made really shows that you're open to learning and improving which is awesome to see. I haven't been doing this very long, but I see tons of people out there shut down after receiving some constructive criticism and their driving gets worse.
 

El_Tortuga

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Nice writeup. Don't beat yourself up though. Everything you've described is completely normal for getting acclimated.

Trust that things will slow down mentally when things start getting embedded into your subconscious thought. You'll establish a rhythm and flow that is soooooo addicting.
 

Strengthrehab

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Next track day, i'm going to print out the track map and set up my own graphical representation of the line, shift points, etc.

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SoundGuyDave

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Next track day, i'm going to print out the track map and set up my own graphical representation of the line, shift points, etc.

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EXCELLENT IDEA!! I wouldn't worry over-much about the shift points or braking points from a graphical perspective (can vary too much based on actual grip levels and conditions), but this is an excellent opportunity to do a little bit of thought-exercise... First, you know the old adage that "A plan never survives contact with the enemy," right? In this case, the track IS your enemy, and needs to be conquered!! Write the plan, but be ready to adapt it to what you actually experience. A track map won't show you a little pavement ripple right on the ideal line that makes missing apex by 3' the faster way around... Or an odd camber that might make a mid-track entry the right decision. ALL THAT SAID: When planning a line around a new track, start with the corner leading to the longest straight, and make that priority one. Then the corner leading to the second longest straight, priority two. And so on. If you have a corner that leads into a corner that you've already plotted a line on, then sacrifice that corner as much as needed to put you into proper position for the entry into the higher priority corner. This is particularly important with corner-pairs, which might be joined by a very short straight. If you just NAIL the first corner in the pair, you might just find yourself on the wrong side of the track for entry into a corner that leads to a 1/4-mile straight. Let the first corner suck, deal with the 200' stretch between them, then nail the second, leading onto the long straight. Look for corner-pairs where it may make sense to take a double-apex line through the two of them, keeping the car loaded up and at higher speed net, rather than treating them as two separate corners, with a lift or brake tap between them to set up the "ideal" line through each one individually.

Autobahn Country Club South Track (I think a pretty typical club track) is loaded with stuff like this!

track-map.jpg


First, look at the T9/T10 combo. T9 is ~120* right-hander, with a short straight leading into ~100* left hander. If you take the ideal line through T9, you'll track-out to the left, which puts you WAYYYYY offline for entry into T10, which leads onto a nice, juicy, 125mph straight. Bad decision. The "real" line through there is to sacrifice T9, braking late, hard, and taking it wayyyyy deep into the corner before making a brutally tight turn, with track-out all the way to the RIGHT edge of the track. That sets you up for a hard charge into T10, with a late-apex to take advantage of that nice, straight pavement.

T11/T2/T3 is another complex that requires sacrificing the "ideal" line through the corners in isolation. Work it backwards. There is no real "straight" between T1 and T2, and between T2 and T3 is a short straight. Exit of T3, however, is a nice long stretch of pavement, so you would want to prioritize T3. That means that the exit from T2 needs to be "offline" to the right edge of the track, as the straight really isn't long enough to transition back over. So, that means that T2 is going to have an "odd" entry and apex to set that up. You could take a traditional line through T1 and still drop on-line for the entry into T2, but that would require unloading the suspension slightly at exit of T1, then shedding a bit of speed and re-loading the suspension for the tighter entry into T2. Here, the "real" line (there are three through there depending on chassis type!!) for a pony car is to take a mid-track-ish apex point at T1, and let the wider arc continue right into the offline arc for T2. There's a little throttle-steering involved in line and load management through there, and it just feels wrong when you're trying it, but you soon realize that you can really carry a lot more speed through the complex when treated as a segment rather than individual corners.

These sort of mental exercises, looking at track maps will make you a thinking driver, and let you prioritize the various segments and corners on the track. Then, when the rubber meets the road, you just need to refine your original "ideal" line to reflect reality. If you look at the track map, T13/T14 could be treated just like T1/T2, with a mid-track apex in T13, nailing T14. Except... At this particular track, there is a linkage road that connects the north course to the south course and dumps in between T13 and T14, and it's cambered. So, when you're outside there, the pavement transitions to an off-camber section with a mild bump. In a stock-ish suspension car, it's not that big of a deal, slightly unsettling, but manageable. In a heavy-spring stick axle car, though, that can kick you flat sideways, so the "real" line through there is to treat T13/T14 as a double-apex corner with a single arc through them, sacrificing (from data) about 2mph in mid-corner speed for the smoother exit line, which allows more power, sooner, and is (for me, in my car) about 0.08 seconds quicker at the end of the lap. Not quite a tenth, but, if you have half a dozen "not quite a tenth" situations in a lap, that can add up to a half-second delta, which is a lot!!

Bottom line, after all my rambling, is that the thought-exercise of plotting a line on the track map is absolutely valuable, but you need to be ready, willing, and able to chuck the work you spent hours considering and analyzing right out the window when you're faced with the track in reality.

Now, how to tell if your "projected line" is good or not before taking your first lap in anger? Read the track!! This is super-secret sauce (not really!!), but on your recon lap (the outlap before coming to the green at start/finish) is your perfect opportunity to take a look at things. You're at a slower pace, not worried about traffic management, etc. Look at the color of the track. Yes, it's all grey, but look at the shading! The darker strip is where the rubber has been ground into the pavement, and will show you where MOST of the folks put their cars through the corner. Note that this can be reversed, if there's a layer of sealer on the track, and they run a lot of street-tire events, as all-seasons have loads of silica in the tread compound which grinds off the darker sealer. At entry, apex and exit, look at the berms: if it's beautiful candy-stripe paint, not a lot of cars are running there. If it's full of rubber marks, that's where the racing line is! Also look for dirt patches as well... Those are created over time where the racers are consistently dropping one wheel at entry/apex/exit trying to use as much of the track (and then some!) as possible. Those points ARE on the racing line. So, during your recon lap, just start connecting the dots. Skid marks from brake lockup at entry, follow the grey arc, rubber on the berm at apex, dirt patch past the berm at exit... If your "projected" line isn't using these landmarks, you may want to consider altering your plan. THEN figure out why your plan didn't work there, so you may learn somehting for the next track...

Here's vid Video of that track for a more visual explanation of the lines I take and some of the comprimises made to suit the track. Also note that I did the entire track in 3rd and 4th (4th and 5th for you), with a 6500RPM limit. Again, 3.73 gears, 25.5" tires, so your mileage may vary. The vid starts at entry into T10 for reference, and the flag stand is between T15 and T1.
 

Strengthrehab

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Here is a track map of MSR-H.
f4f6eb85ee8ffc989d05b39da176b6e9.jpg


We ran CCW

Here is a video from Terry at Vorshlag running an event there.
http://vorshlag.smugmug.com/Racing-Events/NASA-at-MSR-H-011814/i-RbpMvQk/A

I was shifting all wrong the whole time. For example, the straight approaching diamond edge, i'd be in 5th (4th probably more appropriate) then i'd down shift to 4th for first corner then again to 3rd for the 2nd corner. I'd then shift to 4th and 5th on the back straight, downshift to 4th before the turn (turn in too quickly and pinch the turn too) then brake and downshift to 3rd for next turn then downshift to 2nd for the next turn entering the keyhole. I'd then upshift to 3rd after the keyhole then 4th for the launch (instructor was in 5th) then down to 3rd for sugar and spice.

All in all, 3rd and 4th should have sufficed.

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Voltwings

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I like Terry's comment about respecting the pit wall. I spun my last session on Sunday my last time there, and i just went both in, didnt try to save it. In hindsight that was probably smart, because if i tried to save it and over corrected the car may have very well snapped around and i'd have gone head first into the wall. That's a tricky corner to nail.
 

Strengthrehab

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I like Terry's comment about respecting the pit wall. I spun my last session on Sunday my last time there, and i just went both in, didnt try to save it. In hindsight that was probably smart, because if i tried to save it and over corrected the car may have very well snapped around and i'd have gone head first into the wall. That's a tricky corner to nail.
Yeah, that wall comes at you fast.

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