GT Redline

[DivineStrike]

Gary lol, he is saying the engine is still making power...not that the power is increasing

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[Todd15Fastback]

Well, Todd, no I'm not. Don't have to be to understand how an engine operates and then mesh that with Fords own #'s and parameters....and studying dyno runs etc.

Since I taught internal combustion engines....gas and diesel and taught high by pass turbine engines and thus worked with engine experts doing research and studies....yeah...I can understand and hope to explain the basics here pretty well. Got paid a lot of money doing it..and certified to teach it all....so, I think I know enough here to deal with this issue.

And you??

Great to hear!

I am an IT executive and expert for all things databases, PCI, encryption, etc. Been a car lover since I began driving at the age of 16. Helped build some 289 hi-po and stroker 427 motors from the one of the blue oval legends, Holman and Moody.

 

[Grintch]

M

Vacuum gauge is helpful in hyper-miling.

Which is just what I want in my V8 GT PERFORMANCE PACK. Might as well put a Rolls Royce style power gauge in a Prius.

 

[JimmyTwoTimes]

M

Which is just what I want in my V8 GT PERFORMANCE PACK. Might as well put a Rolls Royce style power gauge in a Prius.

Well, I don't know about you, but I enjoy hypermiling my non-PP GT. It's really fun to watch that fuel economy gauge top up at 40 as you go into neutral on downhills and hit the gas on uphills with the strength of a soft breath.

 

[Charles147]

I have the PP and I enjoy observing my mpg's results. I'm no hyper-miler by any means though. Plenty of threads pop-up regarding mpg's.

I get a kick out of it not because of financial reasons because I agree with the fact that buying a GT (w/PP or not) is not the most fuel friendly vehicle to shop for...I observe the vacuum gauge and mpg because I'm obsessed with the car and find it interesting to know how my driving style/behaviors can change the fuel economy.

 

[Grintch]

Grintch, power falls off pretty quick after peak power in the GT. Here is my dyno for reference

OH MY GOD, the power has dropped off 5 hp. I need to shift now where the engine will have 70 less hp in the new gear [with less torque multiplication].

Per your chart HP at ~6750 - 375
HP at ~ 4600 - 305 (RPM after a 1-2 shift)

Do I need to explian why having 305hp is slower than having 375? Basicly you don't want to shift until you will have the same or more horspower at the new rpm point in the next gear. This is why shifting at your power peak is stupid, because it guarantees that this will not be the case.

Another approach for determining optimum shift points is to calculate the torque x the gear ratio, and shift when the that value in the next gear is the same or greater than in the current gear. I have to do some extrapolating of the 6500+ drop off and will do that tommorow.

 

[DivineStrike]

Gary, engines make power as long as they are running lol it just might not be much. Stop getting so flustered

Btw with the digital tachometer in engineering mode the cutoff is 6850

Grintch, look at the dyno in the video. It drops off dramatically by 7k...my dyno only went to 6800 rpms...at about the point you want to shift

 

[Hack]

You said it...MAX hp with 93 fuel is made at 6500....power is made, but, at what price? For what reason going any farther?

So, 500 to 1000 above peak power...which is 6500....OK...so that's 7000 to 7500...right? Wrong. This engine will be shut down at 7000. So, shifting up there is useless and does not make any sense.

Peak hp is at 6500......peak torque is at 4250. You figure out what you want for pulling power....max rpm or max torque?

Bama Tune did a dyno pull, stock, with tune, and with JLT CAI. Max gain was 28 hp and 50 lb ft. of torque with the CAI and tune. Just a tune approx. half of those figures.

Stock dyno pull: HP - 368 at 6400 rpm. Torque: 345 at 4100-4500 rpm. After 4500 torque fell off fairly dramatically to approx. 6900 rpm..engine shut off. HP dropped fairly quickly at 6400 till engine shut off at 6900.

Remember...this is "at the wheels."

So, WHEN does the engine stop makin hp??? On this stock engine dyno run the answer is.....6400. So, YES, the engine stops making power then.

Right at the 6500 # Ford states. Again...remember the 435 hp # is at the flywheel.

There's so much incorrect and misleading information in this post I don't even know where to start.

 

[Norm Peterson]

That tells me that at some point some other limitation comes into play and you're arbitrarily cut off from accessing the rest of what that engine's power curve would otherwise look like. Something like valve springs, perhaps.


Norm

 

[Katastrophe]

The constant dick measuring going on here is laughable. What are we still fighting about here, anyway?

Seriously...someone put up some legit questions/topics we are arguing about here and I'll help clear them up for people who truely don't understand.

 

[Grintch]

Do any of the current tuners raise the fuel cut off points? Have dyno data on the power curve past the stock cutoff point?

Assuming a rather quick drop off in power past 6750, I calculate the following optimun shift points (based on the dyno curve DivineStrike posted).

Availible torque method:
1st - 7300
2nd - 7150
3rd & 4th - 7000
5th - 7300

HP under the curve method:
1st & 2nd - 7250
3rd & 4th - 7000

Obviously this disreguards any electronic or physical limit to the engine RPM (fuel cut, valve float, etc.).

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