Just how much is your power adder helping you?

[Morbid Intentions]

Originally Posted by TRBOPWR Not to nit-pick or anything, but 14.7 - 3.3 = 11.4, not 11.7. good point... I think what I did was rounded 3.3 to 3 and overlooked the fact I did all of this @ like 1 in the morning XD

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[grampa_stang]

According to the NHRA correction factor, NA lose 50% more that FI.
So, when an EVO or STI or Mustang run 13.5 at sea level.
Up at 6000' DA, they run 14.0 and Mustangs run 14.5. That's what sucks.

[Morbid Intentions]

Originally Posted by TRBOPWR

Not to nit-pick or anything, but 14.7 - 3.3 = 11.4, not 11.7.

just to give you an idea of the touchiness in this equation... I went back and edited everything and that 0.3PSI drop gave an overall change in around 4 BHP in our final difference between FI and NA @ 6,000ft.... even if boost pressure was up 2PSI the difference would be even more different

According to the NHRA correction factor, NA lose 50% more that FI.
So, when an EVO or STI or Mustang run 13.5 at sea level.
Up at 6000' DA, they run 14.0 and Mustangs run 14.5. That's what sucks.

just taking 50% off is a little lazy IMO.... the amount of PSI you are running has A LOT to so with the percentage of more power you make

let's take your STI logic @ 6,000DA

stock 2005 STI vs stock 2005 mustang GT vs Terminator

2005 mustang GT
305BHP N/A

2005 STI
300BHP @ 13.5PSI

Terminator
390BHP @ 8PSI


alright... here goes

factoring in 6,000ft the atmospheric pressure surrounding all cars is 11.4PSI

2005 mustang GT equation
11.4PSI/14.7PSI = 78%
100% - 78% = 22%
22% of 305BHP = 67BHP
305BHP - 67BHP = 238BHP @ 6,000ft

2005 STI equation
14.7PSI + 13.5PSI = 28.2PSI @ sea level
11.4PSI + 13.5PSI = 24.9PSI @ 6,000ft
24.9/28.2 = 88%
88% - 100% = 12%
12% of 300BHP = 36BHP
300BHP - 36BHP = 264BHP

2003 SVT cobra
14.7PSI + 8PSI = 22.7PSI
8PSI + 11.4PSI = 19.4PSI
19.4/22.7 = 85%
85% -100% = 15%
15% of 390BHP = 59BHP
390BHP - 59BHP = 331BHP


so as you can see the 50% rule is a GREAT rule of thumb to get you in the general area seeing as the 2005 STI loses 12% of it's power @ 6,000ft and the mustang GT loses 22% of it's power @ 6,000ft (45% more power loss than STI)... but from looking at the equations you can see that @ 8PSI the terminator loses a bit more (GT has only 35% more power loss than terminator) ... also, if the STI upped it's boost pressure it would end up losing less than 12% of it's already increased power... making boost @ elevation a win win situation

let's just assume the STI upped to 17.5PSI and made 370BHP (estimating power numbers to PSI for sake of explanation)

now let's do it again...

14.7PSI + 17.5PSI = 32.2PSI
11.4PSI + 17.5PSI = 28.9PSI
28.9/32.2 = 90%
100% - 90% = 10%
10% of 370BHP = 37BHP
370BHP - 37BHP = 333BHP

so @ stock boost (13.5) the mustang was losing 45% more power @ 6,000ft..... @ 17.5PSI the stang is losing 55% more power than the STI


again, this is just a rough translation and will be looking at fine tuning it... but at this point I think it's safe to say it's a decent little calculator to see just how much power you are losing due to elevation

[Grabber]

So, in a bench racing sense, a GT with 304 BHP won't beat a Terminator with 333 BHP.

Also Brian, where are you getting 7PSI from? If you are thinking Terminators make 7 PSI from the factory, it's actually 8 PSI. If not, disregard.

[Morbid Intentions]

Originally Posted by Grabber

So, in a bench racing sense, a GT with 304 BHP won't beat a Terminator with 333 BHP.

where did this come from?

previous argument with someone else I don't know about? lol


also, I just quickly glanced @ SVTperformance to see stock boost numbers for terminator... someone said 7PSI so that's what I went with, either way it still doesn't change the formula at all

[drhoward]

Originally Posted by Stkjock

Nice write up Brian.....

Howard well with NO2 you have air in a bottle... not quite the same

Thats why I said real men use it, turbos up here can also be problomatic, I know alot of guys with really tweaked turbo race cars and such have to turn their boost down when racing around calgary or else burn out their turbos

(Alot of the rally guys I have talked to have to)

[Grabber]

Originally Posted by Morbid Intentions

where did this come from?

previous argument with someone else I don't know about? lol


also, I just quickly glanced @ SVTperformance to see stock boost numbers for terminator... someone said 7PSI so that's what I went with, either way it still doesn't change the formula at all

Mishri claimed to beat one up to 100 or something like that, or hang with it within a fender. Also, this Cobra was slightly modded too.

Either way, ROFL.

Gotcha on the formula, I just wanted to make sure your info was right. It's 8 PSI. I've personally measure that boost level.

[Riptide]

The guy Mishri raced who had the Termi told him that his car was broken.

I know, ricer excuse...

[Grabber]

Originally Posted by Riptide

The guy Mishri raced who had the Termi told him that his car was broken.

I know, ricer excuse...

Yes indeed. However, Mishri has told that story several times, and holds on dearly to that "kill" or "race"

All good I guess...

[Riptide]

I'd be more curious to see him race one at the track. Or race one myself. I know what should happen but it would be interesting to dissect the slips. I've never seen one at our track. Or a GT500. Mishri's car is the only NA s197 I've seen race out there. One of the downsides in living here in Montucky. There just isn't enough people tracking their cars.