[trackjunkie61]

Had a blast this Sunday at MSR Houston. It was very hot, but the car performed well during the 30-40m sessions (oil-266F, water-214F, trans-190F). First time out on Toyo R888R 295/30r18 tires mounted to Apex SM-10 18x10.5 rims.

I am very impressed with this chassis. It's well balanced and fun at 10/10ths.

This particular track has a sharp corner (appropriately named bus stop) before a sweeping right hander that enters the back straight. All day, I struggled applying smooth throttle during the right hand sweeper. Mid corner, you make a 3rd-4th upshift as you approach the straight. I found myself oversteering numerous times each lap trying to apply the right amount of throttle. The throttle response seemed very twitchy and was difficult to modulate. I was in Track mode with Race setting.

Is this just one of the quirks of the car that makes it "special?" Is a different throttle map available?

[Boost Creep]

Are you fighting with the PTM?



Randy Pobst mentioned the throttle being "...a little too severe, a little too quick...", that might be the same thing you are experiencing.

[Ryephile]

I'm assuming we're talking about a 6th gen SS 1LE? Your profile isn't helping, and your post makes no mention. Given the wheel sizes, you're not running a ZL1, and it's a lot of tire for an LT.

Yes, Track mode throttle is soft for the first half of the pedal travel, and aggressive for the 2nd half. You'll get used to it with seat time. That said, shifting mid-corner is generally frowned upon (in all cars) for the exact reason you mention; the inability to adequately control the car at full-lateral g-loading.



If the Bus Stop is the slowest corner, why are you upshifting to 4th there? Based on TrackHQ's map, Diamond's Edge are the sharpest corners. A 53 foot radius is definitely 2nd gear.

[BigShow1960]

Agree, should not be shifting mid turn.

[GTSLOW]

Shifting in the middle of a turn.

[GuywithL86]

Originally Posted by Ryephile

I'm assuming we're talking about a 6th gen SS 1LE? Your profile isn't helping, and your post makes no mention. Given the wheel sizes, you're not running a ZL1, and it's a lot of tire for an LT.

Yes, Track mode throttle is soft for the first half of the pedal travel, and aggressive for the 2nd half. You'll get used to it with seat time. That said, shifting mid-corner is generally frowned upon (in all cars) for the exact reason you mention; the inability to adequately control the car at full-lateral g-loading.



If the Bus Stop is the slowest corner, why are you upshifting to 4th there? Based on TrackHQ's map, Diamond's Edge are the sharpest corners. A 53 foot radius is definitely 2nd gear.

A 53ft radius turn could be 200mph or 40mph depending on the degree of the turn.

Looks like “the bus” is one slow turn followed by a fast turn, you won’t get to straighten out at all during those, just a fast transition. If you enter at 40mph and your exit is at 80mph how exactly are you supposed to not shift.

What if you’re in a series of S’s that decrease radius as they go on so you need to get faster and faster, you can’t avoid shift mid turn.

“Don’t shift mid turn” doesn’t seem like the best rule of thumb

[Ryephile]

Originally Posted by GuywithL86

...“Don’t shift mid turn” doesn’t seem like the best rule of thumb

The car has a finite friction circle. Upsetting it with a gear change during peak lateral acceleration is an advanced [and delicate] driving technique. Clearly the OP isn't able to do this yet and it's something to work towards in becoming a quicker and smoother driver.

To put it very simply; when driving you're doing one of three things: turning, braking, or accelerating. Notice I said "or". Until you can master those things separately, learning to transition from one to the other smoothly and while staying at the limit of your vehicles' friction circle, doing a gear change at the apex while stabbing the throttle is not going to be part of a quality practice methodology.

The bottom line here is the OP has his shift points wrong for his current level of throttle delicacy and needs to adapt, as routinely spinning out is not in anyone's book for quick lap times.

[trackjunkie61]

Yes, car is 6th Gen 1LE. Will update profile.

Circuit that day was being run clockwise...bus stop, sweeper, back straight. I understand the issue with mid corner shift, but there is no option if you want to setup for the back straight (unless you want to stay at 7,000 rpm for several seconds). For reference, I was exiting bus stop at ~50mph and sweeper at 95mph. Throttle modulation issue was upper revs in 3rd gear under ~1g load.

Main question was really if GM had a revised software download for the throttle mapping. Doesn't sound like that's the case.

Glad to hear with seat time, you were able to smooth out throttle application.

[GuywithL86]

Originally Posted by Ryephile

The car has a finite friction circle. Upsetting it with a gear change during peak lateral acceleration is an advanced [and delicate] driving technique. Clearly the OP isn't able to do this yet and it's something to work towards in becoming a quicker and smoother driver.

To put it very simply; when driving you're doing one of three things: turning, braking, or accelerating. Notice I said "or". Until you can master those things separately, learning to transition from one to the other smoothly and while staying at the limit of your vehicles' friction circle, doing a gear change at the apex while stabbing the throttle is not going to be part of a quality practice methodology.

The bottom line here is the OP has his shift points wrong for his current level of throttle delicacy and needs to adapt, as routinely spinning out is not in anyone's book for quick lap times.

I understand all that, and that applies to likely 95% of turns that you can maintain one gear.

But if you’re in a 40mph and you need to immediately transition to another turn thats an 80mph turn in the other direction, what exactly are you supposed to do?

You can take the turn slower and shift mid turn, or take the turn faster in a single gear and be completely out of the powerband. Or you can try to do both with delicate throttle, which it sounds like he is trying to do. There is no one gear that can handle 40mph and 80mph (just guessing the speed difference)

[GuywithL86]

Originally Posted by trackjunkie61

Yes, car is 6th Gen 1LE. Will update profile.

Circuit that day was being run clockwise...bus stop, sweeper, back straight. I understand the issue with mid corner shift, but there is no option if you want to setup for the back straight (unless you want to stay at 7,000 rpm for several seconds). For reference, I was exiting bus stop at ~50mph and sweeper at 95mph. Throttle modulation issue was upper revs in 3rd gear under ~1g load.

Main question was really if GM had a revised software download for the throttle mapping. Doesn't sound like that's the case.

Glad to hear with seat time, you were able to smooth out throttle application.

And there you have it 50mph and 95mph

What gear would you “dont shift mid turn” guys use?

[Alpha1BC]

Originally Posted by trackjunkie61

Yes, car is 6th Gen 1LE. Will update profile.

Circuit that day was being run clockwise...bus stop, sweeper, back straight. I understand the issue with mid corner shift, but there is no option if you want to setup for the back straight (unless you want to stay at 7,000 rpm for several seconds). For reference, I was exiting bus stop at ~50mph and sweeper at 95mph. Throttle modulation issue was upper revs in 3rd gear under ~1g load.

Main question was really if GM had a revised software download for the throttle mapping. Doesn't sound like that's the case.

Glad to hear with seat time, you were able to smooth out throttle application.

Do you have any video available? Interested in seeing how everything falls timing-wise in the car, especially if you have PDR or something similar that shows the tach, driver inputs, and accelerations.

There's also no mapping change that I'm aware of from GM, but there might be an inline throttle controller on the market that would allow you to tweak the pedal response to your liking.

[Ryephile]

Originally Posted by GuywithL86

And there you have it 50mph and 95mph

What gear would you “dont shift mid turn” guys use?

3rd. 3100 to 5900 RPM, exactly in the thick of the powerband.

[Boost Creep]

lol

[GuywithL86]

Originally Posted by Ryephile

3rd. 3100 to 5900 RPM, exactly in the thick of the powerband.

hmmm, got me there, lol, can't believe those speeds line up that well with 3rd lol.