Much less torque after 6000-6200 rpm normal or issue?

[Shibaman]

I have 4500 mi on my Bullitt. It loves to rev...red line
The motor has plenty of power...but it likes rpm. 80 to 110 in 3 rd gear makes me smile. Pulls to red line like crazy.
My 15 gt had a 7000 red line. Why bother? At 6000 it ran out of power. Dead at 6k. Shift and go. It did have proper short gears . I wish i had those gears in the Bullitt.

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[Burkey]

To begin with, the dyno chart on post #11 is not of a Bullitt, since there weren't any in 2018. And it wouldn't cut off at 6,800 rpm with the 3.73 Torsen, and increased top speed (163 vs 155). At any rate, according to the factory, peak HP is at 7,000 rpm, and peak TQ at 4,600, but haven't seen any dyno reflecting that yet. Maybe because I haven't seen any stock Bullitt dyno (alone) yet.

Finally, the OP needs to remember as speed climbs, the more aerodynamic drag the car will have, slowing it down, so it's normal to feel less acceleration as rpm climb, and speeds exceed 60 mph or so. Also remember this car hits its top speed in 4th gear .

That dyno sheet is absolutely from a Bullitt although they’ve clearly made a mistake on the year model.

Link below:
https://www.motor1.com/news/394274/ford-mustang-bullitt-dyno-video/

 

[Elp_jc]

That dyno sheet is absolutely from a Bullitt although they’ve clearly made a mistake on the year model.

Yeah, no sh*t. Plus they also said 'GT', so with 2 things wrong, rightly thought it was a GT, and not a Bullitt . Anyway, something is off. First of all, it doesn't make sense engine is cutting off so soon; it should hit redline in 4th at 163 on the Bullitt, not only 6,800 rpm, like on GTs. No way our top speed is 163 if that dyno is correct... So what is it? Second, factory figures are peak HP at 7K, not 6,500. And peak TQ at 6,400, not 6,900. Who do you believe???

 

[Burkey]

Yeah, no sh*t. Plus they also said 'GT', so with 2 things wrong, rightly thought it was a GT, and not a Bullitt . Anyway, something is off. First of all, it doesn't make sense engine is cutting off so soon; it should hit redline in 4th at 163 on the Bullitt, not only 6,800 rpm, like on GTs. No way our top speed is 163 if that dyno is correct... So what is it? Second, factory figures are peak HP at 7K, not 6,500. And peak TQ at 6,400, not 6,900. Who do you believe???

I don’t know what you’re looking at but the chart I shared shows the following:
1. The run was stopped at 6800rpm because peak power had already occurred. This has nothing to do with the rev-limiter and is fairly standard practice when you’re simply looking for a peak power figure as opposed to a functional graph that allows you to accurately plot shift points and so on.
2. Peak torque occurs at 4900rpm, not 6400. Ford state that it occurs at 4600rpm.

I’d regard those results as being within the margin of error to be quite honest. I’m sure you’ll get different results from different dynos on different days as is the norm.
The car may have had a bad tank of gas. It could’ve been too hot/too cold in terms of operating temp. There’s a number of variables that could effect the outcome of course but the chart gives an imperfect view of the general shape of the curve, which is a lot more detail than Ford appear to offer.

 

[npole]

Given that torque dictates the rate of acceleration for a given gear, what you’re saying seems fairly consistent with the dyno chart below.

Thanks a lot, this explain it much everything and reassures me that I'm not experience anything "wrong". At the first service will ask them to check anyway, but will save me to just go there asking for additional check.

 

[npole]

I'm still confused how if he's describing just normal TQ drop off how he's NEVER noticed it on ANY car before to the point that he thinks there may be a problem with the car.

My previous car was (still have it) a RX8, that car has very low torque at low rpm and everything goes up (both torque and hp) as higher you could go with the rpm. The optimal shift point for mine was (extended limiter) at 10200 rpm.. it would be better even go beyond that (if you don't care about your engine life). The stock best shift point is at 9400 rpm (right before the limiter). That's why I didn't noticed in my every day driving before. I'm not disappointed, I'm getting used of a 5K V8 now and I like it, it's just very different of what I owned before (I were used to drive like driving a motorbike.. this is indeed different).

 

[npole]

Just returned from more conclusive "tests" and it went much much much better. I think the issue (of when I experienced the "poor" performance) was due to the very high temperature (39°C outside) and by the fact that the "runs" have been done after 1 hour stuck in the traffic (clutch abused?).
Today the temperature was a way lower (sub 30°C) and i did some runs on a straight empty road and it went perfect: there's definitively a loss of torque above 6K but it's subtle, nowhere like when I opened this thread, the car hit the limiter pretty fast in every gear and I can confirm that the hot spot for the gear change (any of them) is around 6800-6900 rpm for the best (acceleration) performance.
No more paranoia... sry for the alarming thread. I can sleep well now.

 

[Elp_jc]

This has nothing to do with the rev-limiter

And who said it had to do with the rev limiter? Rev limit is 7,500. It has to do with the SPEED LIMITER. You could hear the engine cutting off (speed limiter) on that dyno run; it's not like the guy let off the gas. HP was going down a little, but could have been a dip. Basically ALL dyno runs I've seen hit either the rev limiter or speed limiter, so you can see the entire power curve.

 

[Elp_jc]

I can confirm that the hot spot for the gear change (any of them) is around 6800-6900 rpm for the best (acceleration) performance.

With a 6,500 rpm peak, sounds about right. No need to rev it to the limit; less wear and tear too. I'm just surprised Ford is so off on the peaks.

 

[npole]

And who said it had to do with the rev limiter? Rev limit is 7,500. It has to do with the SPEED LIMITER. You could hear the engine cutting off (speed limiter) on that dyno run; it's not like the guy let off the gas. HP was going down a little, but could have been a dip. Basically ALL dyno runs I've seen hit either the rev limiter or speed limiter, so you can see the entire power curve.

That is the reason of why the ECU "tuned" (stock engine) MT82 are performing better on the dyno, a bit it's because of the tuned ECU, but most because with the speed limiter removed, you can hit higher RPMs in 4th gear (that is the gear used for the run).

 

[Elp_jc]

Yeah, I know that. But my point was Bullitts shouldn't be hitting the speed limiter at 6,800 rpm in 4th. That's the case with regular GTs (with 3.55s and 155 speed limits). Bullitts with 3.73 gears and a 163 speed limit should be hitting redline in 4th. That's what doesn't make sense to me.

 

[WildHorse]

Isn't Italy in the mid 30's and higher all week? There's your answer.

 

[BrettT]

I have 4500 mi on my Bullitt. It loves to rev...red line
The motor has plenty of power...but it likes rpm. 80 to 110 in 3 rd gear makes me smile. Pulls to red line like crazy.
My 15 gt had a 7000 red line. Why bother? At 6000 it ran out of power. Dead at 6k. Shift and go. It did have proper short gears . I wish i had those gears in the Bullitt.

Agree. My Bullitt pulls all the way to redline.......

It's was it's birthday on Saturday (2 years), so too it for a little spin. I was on a freeway on ramp in second and held 4,500 rpm until in straitened out, then floored it. It is like being shot out of a cannon!! Blink more than twice, and you will blow by the redline...The tach climbs at a prodigious rate. So fast, it is a real challenge shifting right at redline.......and it doesn't slow down.....

Doesn't cease to impress me......

 

[npole]

I don't think the debate was due to the overall performance of the car, but if that (my car) behavior was normal, and it wasn't... but after have analyzed it, as I specified in a previous post, probably because of the high temperature and stressed clutch (it's just guessing as I have no log to analyze). The engine doesn't push up to the red line, and it couldn't (due to its nature), does it has enough power up to the limiter, of course.. it's a damn 5.0 V8 with 460hp stock, surely it doesn't stop after reaching the peak torque and power, it just perform worse.

 

[zack.whitford]

Agree. My Bullitt pulls all the way to redline.......

It's was it's birthday on Saturday (2 years), so too it for a little spin. I was on a freeway on ramp in second and held 4,500 rpm until in straitened out, then floored it. It is like being shot out of a cannon!! Blink more than twice, and you will blow by the redline...The tach climbs at a prodigious rate. So fast, it is a real challenge shifting right at redline.......and it doesn't slow down.....

Doesn't cease to impress me......

Yeah, there's a downsloped onramp in my area where I like to punch it and it's astonishing how fast the Bullitt accelerates. By the time I'm on the freeway in 3rd I'm approaching triple digits and have to wind it back down.

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