HI all,

I've slowly been building my car with aftermarket management (speeduino) in preparation for an AVY swap, however as it stands I have nowhere to setup the engine I have, nor somewhere to conduct the swap.

I recently upgraded from the stock SPi setup to CBR600 ITBs using a modified (badly) bike carb manifold from a 6N (ABD engine). This has so far given me an estimated 80hp (on standalone, a 1.8 SPi gave 65~hp) using various virtual dyno softwares.

My current head has had a crack ground out, this matched across all cylinders giving a lower compression. After picking up a new head and cam yesterday I'm going to rebuild and skim the head as well as giving it a quick port job as I did on the last.

Spec after head swap will be:

GT double valve spring head with mild porting,

GT cam,

CAD designed CF Nylon manifold using dynamic flow testing,

CBR600rr ITBs - 38mm with 210cc injectors,

Custom trumpets,

Standalone management,

AEE exhaust manifold to 2" pipe with custom silencer (front bumper exit),

Stock AAV bottom end, stock flywheel, 8P gearbox etc.

 

Have seen bike carbed GTs make 90hp, with AAVs making 125hp on dbilas intake and cams. My question is, could my setup, correctly mapped, break the 100hp barrier? I feel the GT cam and exhaust manifold are going to be the main limiting factors.

This is purely for my own experimentation, and to make my car a little quicker in the hill.

 

Cheers.

Probably.

A 1.3 Spitfire would manage 99bhp on twin Webers.

 

It should rev high with double springs and short exhaust.

I think inlet valve size and cam lift will be the limiting factor to air getting in.

More cam duration and overlap would let it rev even higher, but lose torque low down.

 

An ABD probably won't give you more BHP, but it will put more torque in. Conversely, it'll make it less likely to rev, so harder to get BHP from. But then torque's what makes it move. 

 

There's a fair few 95hp GT's in the Club Polo annuls. There's basically 2 ways of doing it.

 

Headwork (big valves, springs, and/or cams)

Fuel and exhaust (bigger throttle bodies, maps, injectors, exhausts, or chuck it all and start again with carbs). Nothing wrong with doing either carbs or injection, it's just about what you're into. 

 

 

 

 

Edited 15 August, 20224 yr by Yeti

Lighter flywheel would let engine spin up faster (smaller parasitic loss) and be able to send more torque to the wheels. 

 

But won't always coast gently up to a junction not touching the pedals in normal traffic because the engine's inertia is reduced.