I run a standard f3 in the back of a Jedi speed event car here in the UK. I bought a 98 f3 race engine with HRC internals(seller didn't exactly know what but did think it had been modified a fair bit) So I was wondering what sort of BHP this engine might produce against my 90 bhp at the wheel standard version.

 

Well, there's many different parts that may have been installed. You need to figure out what they are before guesstimating power-output:

1. high-comp pistons - do compression-test and see if they're any higher than stock
2. valves, springs, & valve-seat cuts - are they stock or larger diameter than stock? Are the springs stiffer for hotter cams?
3. cams - get degree-wheel and time cams. Are the specs any different than stock?
4. cam-sprockets - are they adjustable? any HRC cam would come with adjustable sprockets.
5. exhaust - did you get HRC exhaust with engine?
6. ignition unit - did you get adjustable/programmable ignition unit? This makes bigger difference than anything else.

Last final step, put engine on dyno and measure its actual output. Doesn't matter how trick it is, if it's race engine, it's had rough life and will need to be rebuilt every couple of months anyway.

 

Thanks for the reply dannoxyz, lots to think about. At the moment I believe it's got cams, adjustable sprockets and a race exhaust manifold( to suit a single seater race car) and was told the head's had a lot of work done(ported and polished, valves etc) also got the HRC ignition unit which is in the car at the moment. The engine will be rebuilt over the winter so I'll find out more once it comes apart. I'm hoping to have around 110 bhp at the crank...anyone know what sort of power the race teams engines were getting?

 

I recall race-teams were getting ~130-140 @ crank with:

- lightweight high-comp slipper pistons, 2-rings
- titanium con-rods
- larger titanium intake-valves
- titanium valve-springs and retainers
- fully radiused valve-seats (better than 5 or 7-angle "competition" cuts)
- ported & polished head
- 4-1 long-tube exhaust
- longer duration/higher lift cams customised for above
- adjustable cam-gears
- aftermarket programmable EFI system

You're looking at 16000 RPM redline with all above specs. EFI will give you +10% over carbs due to more precise fuel-metering and 3D ignition mapping. No need to keep on blipping/revving throttle to keep it alive at idle. I recall when doing our FSAE car, we evaluated A LOT of engine configurations and F4i was chosen for highest output for lowest efforts and costs. Honda had done all the engineering work for us already. Those engines were capable of 150bhp when built-up.

 

Excellent dannoxyz, this info helps a lot!

 

Think i saw that motor up for sale and thats awesome you have the hrc cdi unit, you'd struggle to find one if you were looking. Cant speak of the above claims but i'm under the impression from previous research the hrc factory raced bikes were in the 110 wheel bhp on total loss territory but given race series limits engine build, i've heard of a few mad drag builds but never seen any of the claims substantiated in reality.

Would love to see what you're putting the engine in