97 Cobra Shift Points?

[Cobraman]

Anyone have any idea of the best shift points with the stock 3:27 gears?

[STRONGNUFF]

Right before hitting the limiter

[AnthonyS]

Anyone have any idea of the best shift points with the stock 3:27 gears?

I bought my '97 Cobra in October of 1996.... that was a long time ago, but spending 6 months on a submarine will make you do crazy stuff.

Anyway, long story short, I am also an engineer. The goal is to maximize the torque at the driveshaft at all times in order to have maximum power available for acceleration.

I had a spreadsheet at one time that would calculate and graph shift points for any engine torque curve and set of transmission ratios.

Your final drive ratio makes no difference.

So if your engine is stockish and you have a stock ratio tranny, you will want to shift at 7000+ rpm right before the fuel cutoff. You can thank Ford for specing a transmission with the gears way too far apart.

My current ride has 4.10s front and rear (AWD) and a tightly ratio'd 6 speed transmission.... It's a different world all together.

[BoostedD1]

Right before hitting the limiter

^^^This^^^.

[Mach1]

Anyway, long story short, I am also an engineer. The goal is to maximize the torque at the driveshaft at all times in order to have maximum power available for acceleration.

Hrmm I would shift this car at 6500, unless I want to get beat, then I would shift to keep it in max avg tq, say 5k rpm.

[snacksnack]

engineer.

[Baron Von Crowder]

2010?

[AnthonyS]

Hrmm I would shift this car at 6500, unless I want to get beat, then I would shift to keep it in max avg tq, say 5k rpm.

Well then you would lose your ass everytime to anyone shifting at the rev limiter.

The torque you are worried about it torque at the driveshaft. It is heavily dependent on transmission gearing. The gearing in the factory T45 is so far spread it is best to rev to redline in each gear. When you shift from 1st to 2nd too soon you lose a ton of torque. There is speadsheet wandering around in netherspace that I helped a friend make way back in '98 that calculates ideal shift rpm based on torque curve, and TRANSMISSION GEARING. You are leaving out transmission gearing.

[BoostedD1]

1997.

[cool cat]

Hrmm I would shift this car at 6500, unless I want to get beat, then I would shift to keep it in max avg tq, say 5k rpm.

I say you make a friendly wager with Anthony, then go to the track and see what shift points net faster times.

[Shaggin Wagon]

2010?

1997.

Both wrong, its 2015....

[CexMashean]

Pretty sure it's a 2097 year model.
Or 1897. The two are easily confused.

[Cobraman]

Lol wtf. I saw the thread title and thought I created it a while ago.

[Mach1]

Well then you would lose your ass everytime to anyone shifting at the rev limiter.

Yeah, you said what I said, I said rev to 6500, I'd lose every time shifting at 5k rpm to stay in peak torque. I did take trans gearing into account, generally the 1-2 shift is a bit over 2k rpm drop, 2-3 closer to 2k, 3-4 less than 2k drop, etc
Assuming traction is not an issue, I will take my rpm drop, measure it on the graph, and shift where my hp is max avg under that range. People often shift at HP peak because the power falls off, that doesn't help if after the ~2k drop it nets you less avg power. In the graph below, some would say shift at peak hp, 5700. In that case, the 1-2 shift will bring you down to ~3500 rpm or so which is roughly 180hp, if I take it to redline I'm at 245hp after the shift, my avg would be higher, I would go faster.

[Mysticcobrakilla]

I say you make a friendly wager with Anthony, then go to the track and see what shift points net faster times.

But then a super educated "engineer" would be proved wrong and that never happens. Ever!....or daily....or whatever.