The V8 Owners Forum -

Firstly I'm a new noob here so hello to everyone

I've been trying to find some hp figures of what I can exspect from a 4.0 or 4.2 RV8 with the following level of tuning done to it, if anyone can give a ruff estimation it would be fantastic!

4.0 or 4.2

one off stainless inlet manifold (very simple design) (what injectors would I use?) The inlet manifold would basicly be the flange with 8, 1.5" pipes comming off, sett to the best angle to aim the injector right in the camber, very short pipes collected at a stainless box that might taper towards the back slightly with one large throttle bodie at the front, although I was toying with the idea of two one on each side instead about a 3rd of the way down.

Megasquirt mapped to suit

Matched ports

Clean up the ports removing ruff casting and surfacing them (I dont want to go in to shaping the ports apart from matching them to the manifolds)

an apropreate cam with vernier pully

good headers and system

no alterations to the bottom end unless it needs to be stronger anywhere?

at this level of tune is there anything else worth doing that I havent mentiond?

With the engine most likly comming from a Land Rover, being all big and heavy and the engine tuned for this, is there any things that are worth doing to get more power and less torque I suppose because its going in a Capri so its lighter? Like uping the compression ratio or something like that?

Thanks very much for taking the time to read! any hp figures would be very much appreciated!

Hello and welcome
Basic answer is about 190 to 210 BHP.
The reason is that the rover is limmeted by it's cylinder heads so they will only flow in the state of modification you have described to produce about 210 bhp max, the 4.2 will produce more torque lower down and the 4L may make its peek power highe up the rev range, but using "normal" tuning techniques you will be limited to a max of about 210bhp on stage 1 heads.
Your inlet design sounds like a "tunnel ram" manifold, these are good for high revving engines where you don't care about part throttle use and throttle response, great on a drag car where you want all or nothing, however I think you may have a problem with it on a road car, having said that, use something like the throttle body off a GTI golf which has 2 plates, one big one small on a progressive linkage you may be able to "tame" it a bit.
Best regards
Mike

The right cam can make a lot of difference.
my 4.0 race engine failed running a emerald ECU, so to get me running a put a standard 3.9 LR engine in, but with a 4.0 front end and inlet, and shortened trumpets.
I was only getting about 180 BHP, but a camshaft change took this upto 225BHP with standard heads.