Actual vs Engine dyno power

[deadscoob]

Seems a stupid title - actual power should be what it makes on the dyno.

What I'm interested in, is how much power is "lost" from dyno to installation. ie, if you had an AS 550hp engine, it makes 550hp on the dyno, how much will it make when it's in the car with all it's ancilleries etc bolted on?

[steve_d]

Peter Knight (P15ton) is probably the man to ask.
Also depends if the ancilliaries are working i.e. how much power is the alternator making/drawing, is the aircon on?
What difference does the Ultima exhaust make? Mine was dyno'd using Peters own SBC headers so there must be a difference there.

Steve

[andygtt]

you lose some BHP on the headers as well as they use free flow ones to dyno with in the US..... although its actually the torque that they hurt the most on my AS engine.

[J-Dog]

The posted record-setting quarter mile trap speed of 143.68 for the GTR720 calculates out to 673 HP using the calculator at www.angelfire.com/fl/procrastination/quarter.html.

I used 2448 pounds in the calculation. I assumed both fuel tanks full (181 lbs) and a driver weight of 185lbs added to the GTR weight of 990kg in the calculation. The actual weight changes the result drastically. For example, if the fuel tanks contained 2 gallons total, the HP figure dips to 628.

If the driver weighed 350 lbs the HP would calculate out to 718. Hmmm, maybe I should start eating more to raise the power of my engine

[cortina1]

power to weight ratio ratio I understand, weight affecting power output?

[chuntington101]

has anyone ever dropped a AS engine on a dyno over here in the uk to se what they put out in the uk??

also what is the aprroximate drivetrain loss of the G50's??? then you could just run them on chsiss dyno, right??

Chris.

[steve_d]

cortina1 said:

power to weight ratio ratio I understand, weight affecting power output?

Weight affects the power as he is working backwards from a known quarter mile time and trap speed.
The link doesn't work for me.

Steve

[andygtt]

chuntington101 said:

has anyone ever dropped a AS engine on a dyno over here in the uk to se what they put out in the uk??

also what is the aprroximate drivetrain loss of the G50's??? then you could just run them on chsiss dyno, right??

Chris.

Yes and it didn't make as much power... but wasn't as far away as some claim.
The Ultima headers had a bigger impact as I back to back tested these on the dyno.

[chuntington101]

how much diffrecnce did the Ultima headers make compared to the others???

thansk Chris.

[andygtt]

from memory about 10-15bhp peak... but a lot more throughout the rev range. but this is against dyno headers.

[crafty]

The AS engined Ultima still holds the world record and until it's broken by something else, it doesnt really matter about how much HP it has... its the fastest in-da-whole-wide-world.

[andygtt]

J-Dog said:

The posted record-setting quarter mile trap speed of 143.68 for the GTR720 calculates out to 673 HP using the calculator at www.angelfire.com/fl/procrastination/quarter.html.

I used 2448 pounds in the calculation. I assumed both fuel tanks full (181 lbs) and a driver weight of 185lbs added to the GTR weight of 990kg in the calculation. The actual weight changes the result drastically. For example, if the fuel tanks contained 2 gallons total, the HP figure dips to 628.

If the driver weighed 350 lbs the HP would calculate out to 718. Hmmm, maybe I should start eating more to raise the power of my engine

BTW that calculation is only a guide.... it'll be wildly distorted by high reving engines.

[chuntington101]

crafty said:

The AS engined Ultima still holds the world record and until it's broken by something else, it doesnt really matter about how much HP it has... its the fastest in-da-whole-wide-world.

your very right crafty!!

but its also worth mentioning that these "record breaking" engine use the 18degree heads with diffrent manifolds than the "standard" 23degree heads. i think these manifolds where developed by a EX F1 guys and are a work of art!! they probably flow similar to the dyno headers.

thanks Chris.

[mkoch1]

deadscoob said:

Seems a stupid title - actual power should be what it makes on the dyno.

What I'm interested in, is how much power is "lost" from dyno to installation. ie, if you had an AS 550hp engine, it makes 550hp on the dyno, how much will it make when it's in the car with all it's ancilleries etc bolted on?

The guy who tuned my engine said he uses a 25%. So if your engine made 550 on a engine dyno, it's probably puting 412.5 to the rear tires.

mark

[p15ton]

J-Dog said:

The posted record-setting quarter mile trap speed of 143.68 for the GTR720 calculates out to 673 HP using the calculator at www.angelfire.com/fl/procrastination/quarter.html.

I used 2448 pounds in the calculation. I assumed both fuel tanks full (181 lbs) and a driver weight of 185lbs added to the GTR weight of 990kg in the calculation. The actual weight changes the result drastically. For example, if the fuel tanks contained 2 gallons total, the HP figure dips to 628.

If the driver weighed 350 lbs the HP would calculate out to 718. Hmmm, maybe I should start eating more to raise the power of my engine

Or try this one...
Dragstrip Dyno (bang it into google-link is far too long!)
For a completely disagreeing 550ish horsepower ( I lowered the correction to 1.03 which is a fair typical figure)
My experience with drag race engines shows this to be realistic.

[crafty]

Why dont you all arrange a dyno day in the UK and line all your cars up and put an end to the speculation! Get a good tuner to go on the day, do it on a "group purchase" deal, get PH to cover it so the tuner and the dyno shop get media coverage.

[andygtt]

I'd love to see that.

[jschwartz]

My research shows about 20% difference from engine dyno to rwhp in an Ultima. It doesn't really mean it's losing 20%, just the two different methods are 20% apart.

[crafty]

Luck P will bring the LSD and you can make a real day of it!

[luckyp]

Yeeeaaahhhh Maaaaaannnn!!!

Seriously, we should hook this one up. No-one has anything to hide, and it will sort out alot of speculation.

I'll pay my share...........