you tube video of a 320hp A series

edit: damn it! you beat me to it!

For a backyard job.

Enhancements.

Oval port head - assuming it may have been flowed by someone.

Jeff Taylor 140 profile cam (required piston relief, so the valves didn't touch).

The rest was standard bottom end, plus extractors, plus webbers and an A12 lightened flywheel.

A non startling 80hp at the wheels. But it was cheap to do .

Apparently the dyno was set at a high friction (the dyno guy reckoned you may record about 5 more hp on "shoot out" mode".

Hope this helps with some realism. the engine had about 600km on it at the time of dyno.

I have no doubt a well built engine from the bottom up would put this figure to shame.

Driveline losses probably shouldnt be quoted as a percentage, but rather a hp loss figure.

EG. A stock datsun 1200 ute 60hp At the flywheel less 25% drvetrain loss =15 hp Drivetrain loss

if you were to put a 300hp turboA15 in it the same gearbox and diff would be losing 75 hp if you were to use the same 25% drivetrain loss.

Yes maybe more friction and a higher loss but not 60hp more!

I am talking Naturally aspirated. That is what this whole thread is about

Quote:

Mate, you need more than 9:1 comp to get that power. Up the comp to at least 10:1.
The ideal would be 10.5:1.

my sunny with A15 made 91hp @6600 atw on rally tyres. The motor had quite a few competition miles on it and was starting to smoke. The dyno guy estimated it would be about 125 at the flywheel. ported head 11.75:1 cr 45mm carbs (too big he said) biggish cam and restrictive looking press bent 2" exhaust

It takes a relatively non street cam shaft profile to make the numbers you're talking about. And there are a number of variables.
I made 124 odd HP atw on a hub dyno last weekend. But my a15 has forced induction. Come to think of it, if it was turbo rather than supercharged, the number would be higher. I wonder how many horsepower the blower is robbing? I have a picture of the dyno sheet, but I've not fugured out how to get the pics from my camera into my computer. 100 ATW is very do-able, (Which is around 125 ATF) BUT low end drivability is greatly compromised. Most of the cam grinders i've dealt with with try to fit you into a milder grind for a street car. but I Can't be told. Plus the blower means low end drivability isn't an issue.

Some numbers I do know:

A full race built A12 will make 100HP at the wheels. This is a motor with 14-1 compression .490+ lift 300 degree duration cam that revs to 9000+ and makes no power below 5500 RPM's and requires rebuilding every 6-8 hours. Claimed flywheel HP was always 135-140.

Claimed power for a full race A14 is 175HP so WHP maybe 125-130.

Keep in mind these are holy hand grenades and require a 5 speed ultra close gearbox.

For a street motor running on pump gas with a cam that will let it kinda idle I would say 90WHP tops. 100-110 HP at the flywheel in a 1600lb car will go quite well, power to weight wise that's the same as the latest Civic Si or early WRx Subaru.

You also have a whole host of other issues to deal with like driveline etc. I'm finally able to get more aggressive with the engine in my coupe now that I managed to get a mid-close 4 speed (the 4 speed is what I need for vintage racing) hoping for 95ish flywheel horsepower..........or 75 at wheels. End of the day even if your motor makes 110 flywheel horsepower you still should be pretty happy.

Tom