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Moderator
Curtis Jacobson
Portland Oregon
(4576 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Got dyno simulation software?
Posted by: Moderator
Date: October 11, 2010 06:14PM

Can someone with dyno simulation software please run some numbers for me?

Here are the facts I know:

A famous factory-sponsored MGB racer back in the 1960's ran:
- a Holley carb,
- a Camden (Rootes-type) supercharger producing about 20 pounds of boost,
- a custom intake manifold,
- a Derrington crossflow cylinder head with very optimized custom porting,
- a pretty well tuned set of long center branch headers,
- all moving components meticulously balanced,
- wet sump,
- no charging system.

Let's make these assumptions:
(a) 1850cc displacement,
(b) 9,000rpm max,
(c) it took about 30hp to spin the supercharger when at maximum load.

Fuel? Here's the big unknown. One magazine report I've read says this racecar ran on a special cocktail of aviation gas, toluene, and benzene - but I've now received contradictory information from one of the guys who built the engine. He says this racecar ran on Sunoco 5-star pump gas. I'd like to know what horsepower (at the flywheel) might be feasible in each case.

Two things I know nothing about:
(1) How much extra power can you produce by using an exotic fuel blend?
(2) If you're using that exotic blend, can you increase compression ratio (or boost) without detonation to make even more power?
(3) How much extra power can you get from a supercharger?

Please help, even if you only know how to help with parts of the puzzle. Thanks!


hoffbug
Tony Hoffer
Minnesota
(323 posts)

Registered:
10/15/2007 05:25PM

Main British Car:
Olds 215 EFI

Re: Got dyno simulation software?
Posted by: hoffbug
Date: October 15, 2010 12:05PM

Would need to know camshaft specs, compression ratio,and flow data on the head to run a simulation..
Headers have little effect on a forced induction engine.. you dont need to scavenge when the intake charge is under pressure.
Achohol for a fuel is cold when atomized.. Iv e seen E-85 and Methanol carbs ice up at idle....

E-85 blends are 105 octane.. so yes blending fuels can increase your octane rating and allow for more boost or compression than gasoline alone.

How much power from a supercharger??? Nitro top fuelers are around 488 cubic inches and produce over 8000 horsepower .. For a short period of time ..

Power increases of 50 to 100% are common for blown engines

air fuel ratios for max power ( not stociometric) are around..
12.5 to 1 gasoline
6.975 to 1 E-85
6.429 to 1 ethanol
5.5 to 1 Methanol
1.7 to 1 nitromethane.

If the engine in question was running a holley you can pretty much rule out anything over a 10% blend of Nitro and Methanol.. you cant jet it big enough to flow all that fuel..



Edited 1 time(s). Last edit at 10/15/2010 12:07PM by hoffbug.


Moderator
Curtis Jacobson
Portland Oregon
(4576 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Got dyno simulation software?
Posted by: Moderator
Date: October 15, 2010 12:48PM

Thanks!

This is the photograph that inspired my question:
http://www.britishracecar.com/MikeAdams-MG-MGB/MikeHolden-1964-C.jpg
It hung on the wall of a sports car shop in Phoenix, and a label on the photo read:
"1964 271 H.P. MGB 5 MAIN BRG. - BUILT BY CHIEF MECHANIC MIKE HOLDEN"

This article tells most of the story of the engine and the road racing MGB it powered: [www.britishracecar.com]

I've played with some of the online calculators where you just enter rpm, compression ratio, and displacement to get a max horsepower estimate based on an assumption of volumetric efficiency. Obviously, they're a VERY crude tool - plus they're only set up for pump gas and natural aspiration. Keeping in mind that it was a road racing MGB, and probably had to run most of a season without engine rebuild (for economic reasons), I'm thinking that rpm and boost weren't all that high... but this MGB did make a habit of beating V8 powered cars.

I'm still just hoping to determine if that 271-horsepower claim is outrageously high, or just very impressive.

Anyone?


hoffbug
Tony Hoffer
Minnesota
(323 posts)

Registered:
10/15/2007 05:25PM

Main British Car:
Olds 215 EFI

Re: Got dyno simulation software?
Posted by: hoffbug
Date: October 15, 2010 08:45PM

Curtis..
By comparison a friend recently dynoed a 369 CI Ford V-8.. Its a pump gas street engine with a hyd. roller cam and conservative cyl head. and a pro charger F-1 blower running at 20 lbs boost..
It made 830 pounds/feet of torque and 905 horsepower at 6000 rpm. or roughly 2.45 horsepower per cubic inch..

Your engine in question is roughly 113 CI. and at 271 horsepower would be roughly at 2.39 Horsepower per cubic inch at the same 20 lbs boost.. as to strength of the bottom end of the MG engine Ill have to deffer to the experts.. 20 lbs boost will test cylinder head sealing..

I remember reading about the 122 CI Cosworth Vega engine in development making 250 horsepower normally aspirated with 12.5 to compression.. When they got to 275 horsepower they started splitting blocks apart!

So I think its feasible that that engine could have made what they claim..



Edited 1 time(s). Last edit at 10/15/2010 08:46PM by hoffbug.


slow_M
Bernard Holzberg

(59 posts)

Registered:
07/18/2008 11:12AM

Main British Car:
1975 TVR M series Ford 331

Re: Got dyno simulation software?
Posted by: slow_M
Date: October 25, 2010 01:18AM

Here's one weird thing to consider; is that a "B" transmission? It looks like it to my flawed recollection. How did that survive the kind of power we're discussing here?


Moderator
Curtis Jacobson
Portland Oregon
(4576 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Got dyno simulation software?
Posted by: Moderator
Date: October 26, 2010 01:05AM

It is an MGB transmission - and I share your skepticism about its longevity with that much torque on hand - but according to what I've been able to find out, Al Pease's MGB was relatively reliable and the transmission in particular didn't seem to cause DNF's.


roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Got dyno simulation software?
Posted by: roverman
Date: October 26, 2010 11:14AM

Clan, Obviously this team was well funded. Perhaps a trans with custom internals ? Carefully "tuned" torsion hub in clutch. Dual Mass flywheel ? With this kind of performance, no doubt, alien technology was involved. Curtis, how bout you build such a motor, and complete the much loved, "How it was Done". Cheers, roverman.



hoffbug
Tony Hoffer
Minnesota
(323 posts)

Registered:
10/15/2007 05:25PM

Main British Car:
Olds 215 EFI

Re: Got dyno simulation software?
Posted by: hoffbug
Date: October 26, 2010 02:15PM

Alien technology Art?

You know that spaceship in area 51?
The only reason Americans arent flying it is because the Aliens left the toolbox on their planet..


roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Got dyno simulation software?
Posted by: roverman
Date: October 26, 2010 02:28PM

Tony, it's not nice to ridicule, victims of experiments-gone wrong.


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