Top Speed/Rev Limiter

[BossJockey]

The 1-piece Shaftmaster's unit is rated for 7500RPM (shaft speed). That works out to 155mph with the 3.73:1 diff. If you want to go faster, you'll have to go 3.55:1 like the BOSS 302R's.

With the stock tire size (27.1") and 7500 RPM in 5th gear (1:1) you would be going 162 mph (without electronic limitation). 3.55s would get you to 170 but I'd be worried about the stock DS at that speed.

???Wouldn't the driveshaft be going the same speed no matter if you had 3.73 or 3.55?

Yes it would.

 

[12BossKB]

So the Boss has a Mustang GT 2 piece driveshaft then? Hmmmm...I never really thought about the driveshaft. Anyone thinking about going to a 1 piece aluminum?

The 1-piece Shaftmaster's unit is rated for 7500RPM (shaft speed). That works out to 155mph with the 3.73:1 diff. If you want to go faster, you'll have to go 3.55:1 like the BOSS 302R's.

I'm not challenging your mathematics, but I've nailed 155 in 5th gear...twice.

 

[VoodooBoss]

I'm not challenging your mathematics, but I've nailed 155 in 5th gear...twice.

And? Did the speed limiter kick in?

 

[12BossKB]

I'm not challenging your mathematics, but I've nailed 155 in 5th gear...twice.

And? Did the speed limiter kick in?

I didn't notice it kicking in, but I hit 155 and let out of it...

 

[VoodooBoss]

I didn't notice it kicking in, but I hit 155 and let out of it...

Since KB is the fastest color they probably didn't place a speed limiter on all KB Boss 302's.

 

[2012YellowBoss]

Since KB is the fastest color they probably didn't place a speed limiter on all KB Boss 302's.

Wow :stonedSmiley: it is because the YB is faster they HAD to put a rev limiter on it

 

[PTRocks]

So the Boss has a Mustang GT 2 piece driveshaft then? Hmmmm...I never really thought about the driveshaft. Anyone thinking about going to a 1 piece aluminum?

The 1-piece Shaftmaster's unit is rated for 7500RPM (shaft speed). That works out to 155mph with the 3.73:1 diff. If you want to go faster, you'll have to go 3.55:1 like the BOSS 302R's.

I'm not challenging your mathematics, but I've nailed 155 in 5th gear...twice.

That's good to know. It's not like I've been able to explore those limits myself.

Note, I am not talking about the speed limiter, I am talking about the design limits for the driveshafts. To that end, I should restate my previous post to say: "If you want to go faster than 155(ish) without exceeding the shaft's speed limit, you will need to run 3.55 gears." The exact shaft RPM to road speed ratio is governed by both the gear ratio and tire diameter. So larger diameter tires will have a similar effect to running the taller gear.

 

[cloud9]

So the Boss has a Mustang GT 2 piece driveshaft then? Hmmmm...I never really thought about the driveshaft. Anyone thinking about going to a 1 piece aluminum?

The 1-piece Shaftmaster's unit is rated for 7500RPM (shaft speed). That works out to 155mph with the 3.73:1 diff. If you want to go faster, you'll have to go 3.55:1 like the BOSS 302R's.

I'm not challenging your mathematics, but I've nailed 155 in 5th gear...twice.

That's good to know. It's not like I've been able to explore those limits myself.

Note, I am not talking about the speed limiter, I am talking about the design limits for the driveshafts. To that end, I should restate my previous post to say: "If you want to go faster than 155(ish) without exceeding the shaft's speed limit, you will need to run 3.55 gears." The exact shaft RPM to road speed ratio is governed by both the gear ratio and tire diameter. So larger diameter tires will have a similar effect to running the taller gear.

Ok, now I "think" I'm with you If we run the stock wheels/tires and run to the electronically limited 7500 RPM the top speed will be approximately 161 mph given a 26.9" tall tire, 3.73 rear gear in fifth 1:1 transmission ratio http://www.wallaceracing.com/calcmph.php (i.e. there is not a separate "speed limiter" programmed into the ECU)

 

[VoodooBoss]

That's good to know. It's not like I've been able to explore those limits myself.

Note, I am not talking about the speed limiter, I am talking about the design limits for the driveshafts. To that end, I should restate my previous post to say: "If you want to go faster than 155(ish) without exceeding the shaft's speed limit, you will need to run 3.55 gears." The exact shaft RPM to road speed ratio is governed by both the gear ratio and tire diameter. So larger diameter tires will have a similar effect to running the taller gear.

Do you know what driveshafts the 302R & S cars run?

 

[Jimmy Pribble]

302R uses this one:

http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=11824

302S is stock.

Jimmy