hey fellas just about to start the rebuild of an A15 to compete in Idrag here in NZ.
i have found a tomei suppiler here in NZ so some forged pistons and conrods are going in, also port and polish of the head, the compression ratio will raise to about 11:1, i will run 98 and octane booster, and will be running twin 45mm webbers, or 45mm EFI setup. and i might be putting some NO2 into this bad boy as well, depends on the EFI or not. what kind of power and 1/4 mile times will i be making do you rechon? without the NO2 that is in a 72 1200 coupe that is.
please guys any heelp will be appricated.

mmm, for my 2c worth, i reck a 'strong' A15 u can also use on the road should make 165-170hp..
A race engine can get up to 200 from around 1650cc, but they get a bit fragile at those kinda revs
Dunno about 1/4 times, the whole point of the straight line thing is lost on me ...heeeheee.........;)

I don't really know why I'm saying this now - I kept quiet all the way through that how fast are A series? thread...but 200bhp from 1600cc of 2 valve pushrod engine? I'll believe it when I see it... (or get beaten by it) That's 125bhp per litre! that's better specific output than V8 supercars, which are reknowned for being just a little optimistic in their bhp claims. And they have the advantage of the V8 design, although limited to 7500rpm.

now lets see if I can find that formula for converting internet bhp to engine bhp

something tells me this ain't gonna be pretty...

L18_B110, I'm happy to e-mail you a copy of the dyno sheet when my car was last on the dyno - it has 142bhp at the wheels and is 1337cc (A12A).
That should equate to approx 155 - 160 at fly wheel.
You can get more hp our of a A15 and a lot more torque, keep in mind also that the guys above are talking flywheel hp.
where is the V8 power measured? - at the wheels perhaps?
Also keep in mind that the V8's have pretty good tyres, handling & brakes.
Its relatively easy to match power to weight ratio's, but if you can't get it to the ground, stop or go round corners than ya stuffed!

There is a couple of sayings here in NZ ...

- If you have a car that stops and handles well, you have 80% of the race already won (i.e. power doesn't count for everything).

- to finished first, first you must finish.

so you claim only 12% drivetrain loss Brent? A more realistic figure would be 20 to 25, let's say 22% to be fair, meaning your 142 at the wheels is about 182 at the flywheel! a specific output of 136bhp per litre!!!

Of course, chassis dynos are easy to manipulate results and they are really only useful as a tuning tool as individual dynos can vary dramatically, but they are all too often used for bragging rights. you could always add the printout to the photo album

V8 Supercars claim 620 flywheel bhp.

specific output is a comparison of engine output in bhp per litre, I wasn't comparing power to weight.

V8 Supercar engines are controlled by some specific rules, including valve lift , compression ratio etc etc, . If you take a Gen 3 and modify it as you see fit you will surpass 620 HP. It won't be cheap but it's quite possible. Back in the 30's MG ohc engines were getting 200 HP per liter and were setting land speed records of over 150 mph out of 750cc engines. Todays motorcycle engines produce huge amounts of reliable horsepower and can be modded to produce even more with aftermarket parts. Drive train losses can be lessened by running straight cut gears and low viscosity oils. There a a couple of engine builders in Auckland who can produce really big HP A series, due to the fact that they have always been popular here for racing and still are. Competition has always been fierce between them to build the most HP.

I was talking to Jeff talyor (johns brother)about there A series in the race coupe he was saying it has just over 180hp this sounds pretty close to me.I know steve newwings injected a series in the sports sedan was just over 170hp on an engine dyno. Rear wheel dynoes can vary quite a bit I sen the same car pump 140kw on one dyno and 180kw on another it also depends on what gear they do it in they all should be done in 4th gear 1:1 but some guys do it in 3rd so the ramp speed isnt so high. My A14 made 98hp at the wheels on LPR and not much timing advance with good fuel and another 5 or 6 degrees it shouldhave made close to 110 at the wheels or close to 150 at teh flywheel at 7500

That whole rear-wheel-dyno 'subtract % to estimate flywheel HP' isn't accurate at all. For example, with a 5.0 EFI ford, the transmission takes about 35hp, more or less independent of the engine HP. So a 200hp or 400hp engine, subtract not a percentage, but a fixed amount. That makes a huge difference.

Another old-dyno-operators tale is the output sheet. The magazines are testing the same cars on the same day and getting different results on different dynos. They always put disclaimers on the r-w dynos by saying "varies depending on final gearing", etc. And this brand dyno vs. that brand dyno.

100 hp/liter is what the Honda S2000 engine is putting out, and that's with 50-degree camshaft movement, changing-length manifolds and other high-tech tricks. Although if you unlike Honda aren't worried about how long your A15 will last, should be able to go higher. For example, if you run nitro-methane in your A15 anythings possible ... I reckon those MG motors back in the 30s were running special fuel as well.

Yep the fuel was special, but they did it with a 2 bearing crank, that looks like a bent coat hanger !! I agree with you about the fixed transmission loss. Hey Timbo where are you, what was the output on John's engine that Bryan now has , or Vanessa's motor that Ben's now got? They were built 10 yrs ago and were really strong motors. The heads were trick with valve centres moved and all sorts but they were still A series.

Hiya guys.
200 hp from a 1650 engine is only around 125 per litre. Although this is an ask for a 2 valve engine, it's do-able. We dont want to get into the losses thru a chassis dyno, the only hard evidence i have is that my 1300 had 137hp on the engine dyno, and 109 of that got to the wheels. I always assume 25%. My 2035cc FJ makes 213 at 8200 on the chassis dyno, it was 255 the last engine dyno run it got, although development has progressed since...
The big A15 engine that brian ran got to 200 on Marshes engine dyno, they were having to rev it to 'over 8750' to get there.
This was a 'very' trick engine, money was no object here. I remember figures of around $25k just for the long block. We're talking major, major headwork, one head I saw the inlet ports were about 1/2 an inch into the rocker cover (imagine running a mill in at 45 degrees and welding in a square section alloy tube and you're getting the idea)
The big problem was the valves, at those revs with those kind of cam profiles the heads would fall off. I dont think titanium was the answer. The rods were carrillo, the crank was by farrinon I think...
The engine ran motec in it's final days, was dry sumped and would generally last an entire meeting...heeeheeee...
To put the performance of this car in perspective, Brian could run low 65 sec laps at pukekohe all day. Paul radisich did a 61 sec lap in the BTCC mondeo that same year. This track has a huge straight, and horsepower is key. For a Datty to do these kind of times it has to be pretty special.
I dont know where the big engine went, I sure couldnt afford to run a donk like that!!