Top Speed, 6th Gear & What were they thinking?

Mike02z said:

Another OD gear will not help top speed.

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Well you could mess with the ratios. 6th is so deep that it's just a hog. A 7 speed with 6th being closer to say a .82:1 MAY provide more top speed but what for?

Zombo said:

^ Especially since top speed is reached in 5th in the GT350.

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:doh: But why not keep the 6th for example just shy above OD? That way you don't loose that much power on power band drop and you gain a few hundred RPMs for additional top speed?

That would of course mean no proper OD but you'd get possible 180ish mph?

TY for the technical input btw! Saved it on notes as I have to read it again a couple of times...:doh:

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AndreiD said:

:doh: But why not keep the 6th for example just shy above OD? That way you don't loose that much power on power band drop and you gain a few hundred RPMs for additional top speed?

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So here's my question to you then. When will you genuinely use it? Name a track or road course where you'll hit 180+ MPH other than a standing mile event and you're going to need beaucoup more power than what we already have to do that.

nastang87xx said:

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So here's my question to you then. When will you genuinely use it? Name a track or road course where you'll hit 180+ MPH other than a standing mile event and you're going to need beaucoup more power than what we already have to do that.

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You got it. I would want it for the Texas Mile. With the TT kit alone, we'd be able to hit 200 MPH at the Texas Mile if it weren't for 6th gear. I'd seriously consider doing that. But then adding to gear changes (to hit 6th) or final drive changes (to keep it in 5th), adds a bunch more expense. I went down that road of stupid budget with my M3 (hit 186 MPH), not willing to do it with my 350R.

PencilGeek said:

You got it. I would want it for the Texas Mile. With the TT kit alone, we'd be able to hit 200 MPH at the Texas Mile if it weren't for 6th gear. I'd seriously consider doing that. But then adding to gear changes (to hit 6th) or final drive changes (to keep it in 5th), adds a bunch more expense. I went down that road of stupid budget with my M3 (hit 186 MPH), not willing to do it with my 350R.

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Not to be a jerk - but that's not what the 350 was designed for. It was designed for a road course - not a standing mile. I can understand why you'd want to do that, but the truth is this is not the optimal car for it (out-of-the-box). It will require mods.

AndreiD said:

:doh: But why not keep the 6th for example just shy above OD? That way you don't loose that much power on power band drop and you gain a few hundred RPMs for additional top speed?

That would of course mean no proper OD but you'd get possible 180ish mph?

TY for the technical input btw! Saved it on notes as I have to read it again a couple of times...:doh:

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That is certainly feasible, but the GT350 was not really designed for top speed. In looking at the torque curve, in 6th the engine will want to be at ~7200rpm (torque begins to drop off pretty fast after that) for top speed. If 180 is the goal, the 6th ratio would need to be 0.85 to hit 180 @ 7200rpm. I don't think that would be very useful during normal driving in terms of gas mileage. That's a very close ratio spread. Doable, but that was not the objective.

nastang87xx said:

/

So here's my question to you then. When will you genuinely use it? Name a track or road course where you'll hit 180+ MPH other than a standing mile event and you're going to need beaucoup more power than what we already have to do that.

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Agree! It's just for bragging rights or my dick is bigger than yours...:lol:

Oh and that sole moment when you're on a highway and a liter bike is giving you hard time. Or a pig like my K1300R which incidentally has the same top speed as the GT350...and speaking of which I recalled a year ago a short race with an Audi RS5. Rage began after 120mph, he passed me hard as I was crusing at 120mph, and I went full throttle. By the time we both got to 170ish I managed to win back some of the head start he got but we both were apparently stuck at that speed...so the space of max 10 car lengths was kept constant. After a 30 seconds or so at that speed I decided to pull back as the speed alone was He flashed his hazards and off we went each on it's own.

That was the single time I wished I had a liter bike like an S1000RR and smash that RS5

Zombo said:

That is certainly feasible, but the GT350 was not really designed for top speed. In looking at the torque curve, in 6th the engine will want to be at ~7200rpm (torque begins to drop off pretty fast after that) for top speed. If 180 is the goal, the 6th ratio would need to be 0.85 to hit 180 @ 7200rpm. I don't thick that would be very useful during normal driving in terms of gas mileage. That's a very close ratio spread. Doable, but that was not the objective.

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Gotcha! Love reading your inputs man! Cheers! :cheers: :ford:

honeybadger said:

Not to be a jerk - but that's not what the 350 was designed for. It was designed for a road course - not a standing mile. I can understand why you'd want to do that, but the truth is this is not the optimal car for it (out-of-the-box). It will require mods.

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I guess I am a bit puzzled by this because I'm not even disagreeing with you or with the quote I cited. I can't think of any bone stock car, except maybe a Veyron or one or two others in that same exotic category that can hit 200 MPH in a standing mile without substantial modifications. So yeah, mods are required and that part is assumed. The GT350 isn't designed for drag racing either, yet it has a line lock and pseudo launch control. I hate drag racing though and would never use it except maybe to capture some vBox traces. And as far as the standing mile itself is concerned, the GT350 is far better suited than a BMW M3 or almost any other 2WD car. There's already a guy on this forum who took a bone stock GT350 to a standing mile in Nebraska and hit 268 MPH. Another guy at the Texas Mile hit 168.4 MPH. That's far greater than I would have expected from a bone stock GT350. Based on my own experience at standing miles with other similar weight vehicles, horsepower, and 6MT, I would have expected the GT350 to be in the mid to high 150's (tops), and nowhere near the 168 MPH these guys hit. So from from where I'm sitting and looking at the results irrespective of marketing hype, the GT350 is far more optimal out-of-the-box at the standing mile than I would have ever thought. But that 6th gear is the killer that would give me pause about pursuing that 200 MPH dream in this car.

AndreiD said:

Agree! It's just for bragging rights or my dick is bigger than yours...:lol:

Oh and that sole moment when you're on a highway and a liter bike is giving you hard time. Or a pig like my K1300R which incidentally has the same top speed as the GT350...and speaking of which I recalled a year ago a short race with an Audi RS5. Rage began after 120mph, he passed me hard as I was crusing at 120mph, and I went full throttle. By the time we both got to 170ish I managed to win back some of the head start he got but we both were apparently stuck at that speed...so the space of max 10 car lengths was kept constant. After a 30 seconds or so at that speed I decided to pull back as the speed alone was He flashed his hazards and off we went each on it's own.

That was the single time I wished I had a liter bike like an S1000RR and smash that RS5

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After reading all of this I would highly recommend you hit the road course to get some real perspective on "top speed."

nastang87xx said:

After reading all of this I would highly recommend you hit the road course to get some real perspective on "top speed."

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Will do that soon after brake-in is over!

AndreiD said:

Will do that soon after brake-in is over!

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I "broke in" my car at 200 miles with 15 autocross runs. Tight as a drum, no major oil burning at all. Maybe 1.5 quarts over 9000 miles. Drive it like you want to use it.

nastang87xx said:

I "broke in" my car at 200 miles with 15 autocross runs. Tight as a drum, no major oil burning at all. Maybe 1.5 quarts over 9000 miles. Drive it like you want to use it.

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Will do so! I just wanted to respect the factory recommendations but did not baby drive it. Only rarely exceeded 6k RPM and avoided wide open throttle from lower rpms...