Shelby GT HP rated at sea level?

[blueshawk]

Where was the Shelby GT HP rated (dyno'd)? At sea level or in Las Vegas 2000 ft above sea level?

Or are all ratings corrected to sea level?

 

I believe the HP loss per altitude is = altitude (thousands of feet) X .03 x sea level HP rating.

 

If the 319 HP is really at sea level then the HP loss in Las Vegas would be: 2 x .03 x 319 = 19.4 HP!

 

Another reason to hit the beach more often!

[stump_breaker]

Where was the Shelby GT HP rated (dyno'd)? At sea level or in Las Vegas 2000 ft above sea level?

Or are all ratings corrected to sea level?

 

I believe the HP loss per altitude is = altitude (thousands of feet) X .03 x sea level HP rating.

 

If the 319 HP is really at sea level then the HP loss in Las Vegas would be: 2 x .03 x 319 = 19.4 HP!

 

Another reason to hit the beach more often!

 

Per SAI, the SGT is not Dynoed at 319 but "EPA rated at 319".

The 319 rating was to limit the GGT to $1000. They said at 320 the GGT started going up.

These car dyno at more than 319.

I think there was one dyno on here close to 330?

[AFBLUE]

Here's the post from AmyB on the subject

The hp on the car is the same as the GT-H, the problem is when we EPA tested it came out lower, so we are not sure if the test was different, or the GT-H was 319 too even though we were told 325. we ran it again it was 320, so we are saying 319, but with the other upgrades and the bigger rear, it certainly feels like more

http://forums.bradbarnett.net/showpost.php...3&postcount=213

 

I had assumed that the EPA test was a chasis dyno test. Does anyone know exactly what the EPA test is to determine crank HP?

 

My understanding is the GGT is based on MPG not HP output.

http://www.epa.gov/fueleconomy/guzzler/420...2.htm#calculate

[AFBLUE]

Found this on the testing method. Basically it's the SAE J1349, revised Aug 2004 standard.

http://www.mazda6tech.com/images/dyno/sae.pdf

 

Page 10-12 lists required engine equipment

Page 12 begins to explain the lab equipment

Page 13 is the test procedures.

[stump_breaker]

My understanding is the GGT is based on MPG not HP output.

 

I thought the same. I'm parrotting what was said in the plant tour at SAI.

If it is based on average MPG then it's nothing more than theft (from the government not SAI) because according to my onboard computer (take it or leave it) I have yet to get under 22.5 average MPG. I have even seen 25 mpg + or -.

[DreamRide]

I thought the same. I'm parrotting what was said in the plant tour at SAI.

If it is based on average MPG then it's nothing more than theft (from the government not SAI) because according to my onboard computer (take it or leave it) I have yet to get under 22.5 average MPG. I have even seen 25 mpg + or -.

 

 

I recently had mine dyno'd and it came to 280 at the rear wheels. 280 /.85=329.4 hp at the crank. Thats with a loss of 15% parasitic drag.

 

When i made my trip to SAI last month, My car puter said 26 mpg when i arrived there. Around town where i drive more agressivly, is any where from 16-19mpg.

[jimbobbeg]

I recently had mine dyno'd and it came to 280 at the rear wheels. 280 /.85=329.4 hp at the crank. Thats with a loss of 15% parasitic drag.

 

When i made my trip to SAI last month, My car puter said 26 mpg when i arrived there. Around town where i drive more agressivly, is any where from 16-19mpg.

 

 

This confirms what I was told while at SAI recently. That is, that crank HP is 330-335 and the published number of 319 was to minimize GGT.

[Webba]

I thought the same. I'm parrotting what was said in the plant tour at SAI.

If it is based on average MPG then it's nothing more than theft (from the government not SAI) because according to my onboard computer (take it or leave it) I have yet to get under 22.5 average MPG. I have even seen 25 mpg + or -.

 

 

Stump if you are getting that kind of mileage all the time then immediately return your car to SAI cause you aint driving it right son!LOL I only get about 16-17 but I drive mostly around town kind of stuff. Once in a while on the highway and I am usually giving her some shoe when driving

[AFBLUE]

This confirms what I was told while at SAI recently. That is, that crank HP is 330-335 and the published number of 319 was to minimize GGT.

 

Again this doesn't make sense to me. The HP rating has nothing to do with determining the GGT. See my link above for the EPA explanation of how GGT is determined. http://www.irs.gov/pub/irs-pdf/f6197.pdf

 

 

With Ed S' 280 dyno, that makes 3 stock SGTs I've seen the rwhp #s on. 279, 281, and 280. Here's links to the other 2.

http://forum.shelbyautos.com/index.php?showtopic=986&hl=rwhp

 

 

The published number (319) was based on a dynonameter test results using SAE standards. See link http://www.mazda6tech.com/images/dyno/sae.pdf

It wasn't just made up as the published results. Shelby autos was suprised that it didn't come to the originally advertised 325hp.

 

Thus the crank HP is 319 and the parsitic loss is 12.2% or 40HP (based on the 3 dyno results we have).

 

This is just conjecture on my part, but maybe the 2004 revision to SAE power measurements added more components to the testing (e.g. full exhaust system) and thus the previously typical 15% drivetrain loss is now more like 12%. Again just me thinking out loud.

 

Basically the manual SGT has 10 rwhp more than a stock manual mustang GT (based on +20 dynojet Mustang GT runs = 270rwhp avg, and 3 SGT dyno 280rwhp avg). See sheet # 3 of this spreadsheet for the stock mustang GT #s. http://forums.bradbarnett.net/attachment.p...38&d=1181863917

[blueshawk]

Again this doesn't make sense to me. The HP rating has nothing to do with determining the GGT. See my link above for the EPA explanation of how GGT is determined. http://www.epa.gov/fueleconomy/guzzler/420...2.htm#calculate

 

With Ed S' 280 dyno, that makes 3 stock SGTs I've seen the rwhp #s on. 279, 281, and 280.

 

The published number (319) was based on a dynonameter test results using SAE standards. See link http://www.mazda6tech.com/images/dyno/sae.pdf

It wasn't just made up as the published results. Shelby autos was suprised that it didn't come to the originally advertised 325hp.

 

Thus the crank HP is 319 and the parsitic loss is 12.2% or 40HP (based on the 3 dyno results we have).

 

Basically the SGT has 10 rwhp more than a stock mustang GT (based on +20 dynojet Mustang GT runs = 270rwhp avg, and 3 SGT dyno 280rwhp avg). See sheet # 3 of this spreadsheet for the stock mustang GT #s. http://forums.bradbarnett.net/attachment.p...38&d=1181863917

 

 

 

Based on the average stock GT RWHP of 270 hp and a crank rating of 300 hp, the parasitic loss is 30 hp or 10%. but the SAE rules use 15% which would mean the stock GT hp rating should be 317 hp and the Shelby GT should be 329 hp.

 

I expect 319 hp is a minimum and it probably is closer to 329 hp.

[stump_breaker]

Stump if you are getting that kind of mileage all the time then immediately return your car to SAI cause you aint driving it right son!LOL I only get about 16-17 but I drive mostly around town kind of stuff. Once in a while on the highway and I am usually giving her some shoe when driving

 

I don't know. Maybe it's because we do mostly highway driving.

My road trip from TX to Vegas and all over netted 24.3 average per the computer by the time we got back home. We ran 65-85 all the way and once we hit Tx I got behind a chicken hauler who was running 90 for about 4 hours.

[jimbobbeg]

Again this doesn't make sense to me. The HP rating has nothing to do with determining the GGT. See my link above for the EPA explanation of how GGT is determined. http://www.epa.gov/fueleconomy/guzzler/420...2.htm#calculate

 

 

This is what I was told by SAI.

 

I do believe there is more to the caluclation. I applied the calculation method at the EPA site to the 2008 GT500 and it's new fuel economy numbers and came up with a GGT of $3000 for MY 2008, yet the GGT was unchanged at $1300.

[AFBLUE]

Based on the average stock GT RWHP of 270 hp and a crank rating of 300 hp, the parasitic loss is 30 hp or 10%. but the SAE rules use 15% which would mean the stock GT hp rating should be 317 hp and the Shelby GT should be 329 hp.

 

I expect 319 hp is a minimum and it probably is closer to 329 hp.

 

 

Well until someone performs another SAE test at the crank, 319 is the only official result we have. The rest is just conjecture.

 

The 15% is not an official rule, it's just a rule of thumb. Not every drivetrain loss is the same. Some are better than 15% some are worse. Looks like the Shelby GT is 12.2% or 40hp.

 

Here's an interesting read that shoot holes in the idea there there is a set percentage for a drivetrain loss. http://www.f150online.com/forums/sho...6&postcount=13

Dyno owner tests the same F-150s before and after engine swaps (4.6L to 5.4L). The drivetrain stays the same so the drivetrain loss percentage should stay the same too. It doesn't, but the overall loss in hp stays about the same (35hp).

Now in the manual-tranny vehicles, the 5 & 6-speed manuals tend to lose (in round numbers) about half as much power as the automatics do - so a typical 220 HP non-PI 4.6 5-spd. 1997-1999 F-150 sees about 185 RWHP in stock trim on an ideally-running stock truck, just for example (though we've seen a number of them hit only 170-175 stock). So now we're talking about a 15.91% loss. But drop a 5.4 260 HP motor in that same truck as a number of our customers have done so that they can have a 5.4 manual-tranny F-150 (which Ford doesn't make), and the driveline loss stays close to 35 HP (it might hit 38-40 HP), which then represents a 13.46% loss.

[ilmor]

To me, its just annoying that its posted at 319. Give me 320, or 325 and just hate that odd number. Isn't that finicky?

[AFBLUE]

With Ed S' 280 dyno, that makes 3 stock SGTs I've seen the rwhp #s on. 279, 281, and 280. Here's links to the other 2.

http://forum.shelbyautos.com/index.php?showtopic=986&hl=rwhp

 

 

 

Just found another dyno run on you tube. 293rwhp and 312rwtq.

 

 

That's at least 334 hp at the crank (using 12.2% loss).

 

I'm not sure if this was stock or after a tune. Based on the other 3 results (279, 280, and 281) I would think it's after a tune. If so then it's shows how conservative the FRPP tune is.

 

I asked the question on y-tube and I let you know if I find something out.

 

 

EDIT:

Ok, I may already have the answer.

http://www.sloppymechanics.com/archive/07-...07-31-2007.html

 

Monday, July 02, 2007

Shelby GT Tune

Timmy was tuning a shelby GT today on the dyno, it just had a set of headers installed as far as i know, stock exhaust still wich is very loud! It picked up 20 hp to the wheels, and another 5hp with a timing advance. I was snapping a few pics of it i took two of troys cobra. Here are the pics and video

 

 

So 293rwhp-25hp = 278rwhp. So that's 4 cars that dynoed between 278-281. Very tight and consistent range.

[DreamRide]

Just found another dyno run on you tube. 293rwhp and 312rwtq.

 

 

That's at least 334 hp at the crank (using 12.2% loss).

 

I'm not sure if this was stock or after a tune. Based on the other 3 results (279, 280, and 281) I would think it's after a tune. If so then it's shows how conservative the FRPP tune is.

 

I asked the question on y-tube and I let you know if I find something out.

Ok, I may already have the answer.

http://www.sloppymechanics.com/archive/07-...07-31-2007.html

 

 

 

 

So 293rwhp-25hp = 278rwhp. So that's 4 cars that dynoed between 278-281. Very tight and consistent range.

 

 

 

 

Thats after the tune