dyno power v rolling road

[dal2litrefrogeye]

Hi all just a thought, just having a nose on the amerian speed web site and looking at their various specs of power , ( iv got one in mine 517 bhp @ 6600 rpm "dyno sheet" ) so whos had their car on the rollers and how close to the A S spec was it ( yep i appreciate trans loses etc ) , not trying to create a pro/anti A S argument , as i said just a thought ?

[DHGTR]

I wouldnt have thought you could compare the two because you dont know what the losses are going to be, you would just be guessing. Surely you would need someone that has unpacked their engine and put it straight onto another dyno here?

[738 driver]

It wouldn't really be comparable, nor fair...... too many variables, eg fuel, ambient conditions, headers, dyno set-up, installation, type of test procedure etc, etc,etc......
Just accept whats on your current bit of paper.
With newer technology its easier and IMO better to get the results during either simulated or actual running conditions i.e. in the car.....hub or road testing.
Just a few hours work and the right approach you can normally transform 550 grumpy, popping, farting HP into something quite civilised for road/occasional track use.

Edited by 738 driver on Sunday 20th December 17:24

[dal2litrefrogeye]

DHGTR said:

I wouldnt have thought you could compare the two because you dont know what the losses are going to be, you would just be guessing. Surely you would need someone that has unpacked their engine and put it straight nto another dyno here?

hi Dave i would disagree a about not knowing what the losses are going to be a decent rolling road ( and operator ) can tell to within a few bhp how much the trans etc are loosing but i do appreciate differnt fuels / temps can make a fair difference , hands up i was just being a bit nosey to see if anyone s put their car on the rollers and its been way of the mark ( either way ?) , oh on the subject anyone reconmend a RR that is ofay with sbc / holley etc , im in north kent / sarf london , but dont mind travelling ( i take my zetec powered sprite up to northampton motorsport ) but they were a bit erm and arr about having jets etc for holley s , cheers for any ideas, Dal

[JoulesCanAm]

738 driver said:

Just accept whats on your current bit of paper.

I would argue that the other way, a bit of paper is just that, like many engine builders I would speculate that AS have a model build/parts etc. and don't even Dyno each unit or use a desktop dyno. If they do dyno run each one I bet they use race gas and open headers to maximize their HP printout.

IMO put your car on the dyno and what you have is what you have.... a true measure of BHP to the ground for your build, anything else is just for "bench racing" bragging rights.

Julian

Edited by JoulesCanAm on Sunday 20th December 18:39

[738 driver]

Joules........ 'Current'.... meaning latest test/source of info , wasn't meant to be specific to the OP's current position.

[JoulesCanAm]

738 driver said:

Joules........ 'Current'.... meaning latest test/source of info , wasn't meant to be specific to the OP's current position.

Sorry, misread your meaning.

[straker]

in answer to dal, if you dont mind the travel how about 'john sleath race cars' in Doncaster? he has lots of experience with sbc and holleys, keeps loads of jets in stock, has a rolling road and engine dyno, google is your friend for his website, he looks after a couple of ultimas both with sbc's . . hope this helps . .

[LuckyP]

dal2litrefrogeye said:

Hi all just a thought, just having a nose on the amerian speed web site and looking at their various specs of power , ( iv got one in mine 517 bhp @ 6600 rpm "dyno sheet" ) so whos had their car on the rollers and how close to the A S spec was it ( yep i appreciate trans loses etc ) , not trying to create a pro/anti A S argument , as i said just a thought ?

My 550 AS engine, when installed was 497 on the rollers.

Pretty much expected and normal.

Your 517 would be 467 ish

[JoulesCanAm]

LuckyP said:

My 550 AS engine, when installed was 497 on the rollers.

Pretty much expected and normal.

Your 517 would be 467 ish

Is that actual or corrected in any way for ambient temp, altitude etc. and transaxle losses?
If it is uncorrected then that is damn good I'd say. My tuner guy does a lot with Porsches and says a G50 will sap about 13% of the flywheel HP.

Edited by JoulesCanAm on Wednesday 23 December 04:21

[budala]

My AS engine was 540 hp on the dyno and five years later 430 hp on the bench...
So I'm on the LS7 way.

[V8Dom]

budala said:

My AS engine was 540 hp on the dyno and five years later 430 hp on the bench...
So I'm on the LS7 way.

r but what will your LS7 produce in 4 years????

An engine used in anger in a Ultima is going to have wear in the pistons and rings,and encounter valve seapage due to tiny dontact areas and loose compression and power. Whether you have an AS derived chevy or an LS engine this will alway happen. However the past threds have always been what does an AS engine produce straight out of the box?? Be interesting to see what HP a LS produces straight out of the box and also advertised at American speed then we will see their way of measuring??

Dom

[ultimaCZ]

V8Dom said:

budala said:

My AS engine was 540 hp on the dyno and five years later 430 hp on the bench...
So I'm on the LS7 way.

r but what will your LS7 produce in 4 years????

An engine used in anger in a Ultima is going to have wear in the pistons and rings,and encounter valve seapage due to tiny dontact areas and loose compression and power. Whether you have an AS derived chevy or an LS engine this will alway happen. However the past threds have always been what does an AS engine produce straight out of the box?? Be interesting to see what HP a LS produces straight out of the box and also advertised at American speed then we will see their way of measuring??

Dom

I dont buy that. When I got my AS 450HP engine several years ago, the dyno sheet showed something around 460 HP. Shortly after running the engine in I put it on the rolling road and they just got something above 300 HP out of it (approx. 310 or so). Of course I cant varify whether the rolling road was showing correct values but I was pretty disappointed. Now I have the LS7 (560 HP at Jeffs Dyno) and it scares the hell out of me... It definitely feels like 200 HP more than the AS engine.

[LuckyP]

JoulesCanAm said:

LuckyP said:

My 550 AS engine, when installed was 497 on the rollers.

Pretty much expected and normal.

Your 517 would be 467 ish

Is that actual or corrected in any way for ambient temp, altitude etc. and transaxle losses?
If it is uncorrected then that is damn good I'd say. My tuner guy does a lot with Porsches and says a G50 will sap about 13% of the flywheel HP.

From what I recall, this was estimated flywheel. The actual measured at the wheels (so inc that 13% loss you are quite rightly talking about) was 420.

[JoulesCanAm]

LuckyP said:

From what I recall, this was estimated flywheel. The actual measured at the wheels (so inc that 13% loss you are quite rightly talking about) was 420.

I would ask why you consider 10% less than the AS quoted figure as 'normal'? I wonder if all that is in the open headers and gas octane rating?

FWIW mine came in about 10% less too, 600HP quoted from AS came in at 540 with corrections for transaxle and altitude (5000 ft), running pump gas.

Julian

[LuckyP]

JoulesCanAm said:

LuckyP said:

From what I recall, this was estimated flywheel. The actual measured at the wheels (so inc that 13% loss you are quite rightly talking about) was 420.

I would ask why you consider 10% less than the AS quoted figure as 'normal'? I wonder if all that is in the open headers and gas octane rating?

FWIW mine came in about 10% less too, 600HP quoted from AS came in at 540 with corrections for transaxle and altitude (5000 ft), running pump gas.

Julian

Headers for sure. Or more specifically the header mounting flanges that overlaped the exhaust ports by a scary amount!!

[budala]

V8Dom said:

budala said:

My AS engine was 540 hp on the dyno and five years later 430 hp on the bench...
So I'm on the LS7 way.

r but what will your LS7 produce in 4 years????

An engine used in anger in a Ultima is going to have wear in the pistons and rings,and encounter valve seapage due to tiny dontact areas and loose compression and power. Whether you have an AS derived chevy or an LS engine this will alway happen. However the past threds have always been what does an AS engine produce straight out of the box?? Be interesting to see what HP a LS produces straight out of the box and also advertised at American speed then we will see their way of measuring??

Dom

Honestly, at the moment I don't care what my LS7 will produce in 4 years...

I would like it produces something NOW !!!

[spatz]

ultimaCZ said:

V8Dom said:

budala said:

My AS engine was 540 hp on the dyno and five years later 430 hp on the bench...
So I'm on the LS7 way.

r but what will your LS7 produce in 4 years????

An engine used in anger in a Ultima is going to have wear in the pistons and rings,and encounter valve seapage due to tiny dontact areas and loose compression and power. Whether you have an AS derived chevy or an LS engine this will alway happen. However the past threds have always been what does an AS engine produce straight out of the box?? Be interesting to see what HP a LS produces straight out of the box and also advertised at American speed then we will see their way of measuring??

Dom

I dont buy that. When I got my AS 450HP engine several years ago, the dyno sheet showed something around 460 HP. Shortly after running the engine in I put it on the rolling road and they just got something above 300 HP out of it (approx. 310 or so). Of course I cant varify whether the rolling road was showing correct values but I was pretty disappointed. Now I have the LS7 (560 HP at Jeffs Dyno) and it scares the hell out of me... It definitely feels like 200 HP more than the AS engine.

that is refelecting my opinion, do not believe in dyno sheets