The V8 Owners Forum -

Hi guys:

Just been throwing some thoughts together about trying to up the torque and power output from my 4.6HSE Rover V8.

It's a GEMS ECM, and the engine is a 'Genuine Exchange' unit, fitted in 2004 @ 110k miles. The car has done approximately 50,000 miles on this unit. It's had very regular oil changes (every 4 or 6 thousand miles) using Silkoline 5w40 synthetic race oil since 120k. It's not been overheated.

The ECM does have a Mark Adams chip fitted. It was one Mark sent after a phone call, not after rolling road tune. It's roughly set up for non-LPG use on high quality/octane fuel. I won't run LPG or use poor quality fuels in the car.

I have a DoubleS cat-back exhaust fitted as well. It is the single system (as it's a 1994/5 p38). I'm considering the DoubleS 200cpi metal cats for my birthday.

Now, I understand realistically, the p38 is probably limited to maybe 300bhp as the ZF24 gearbox is probably around it's limits above this. I only guess this as Overfinch say they uprate their ZF24's to take the 330bhp for the 5.7 SBC conversions. I also realise that in an ideal world, top hat liners should be inserted, but that would mean a big engine build. I don't want a big build just yet. Maybe in the future when the engine does break, a StageIII 5.0 V8Developments unit can be slotted in?

For the moment, my thoughts are around some mild changes, mainly the cylinder heads. Reading around, the standard cam is ok for its purpose. Chatting to Mark in the past, the injectors need replacing. He also mentioned the sport cats were handy for tuning. Modified trumpets etc...?

Thoughts please Gentlemen?

Head work to allow the engine to breath properly. Having said that, it may well compromise low end torque if you go all the way.

Camshaft too. There are loads to choose from.

I would discuss with Mark Adams, as you need to be sure that your final combination will work with the ECU.

That oil you have been using sounds a bit thin?

Chris.

Thanks for the reply, Chris.

Yes, I suppose it is down to heads. Who do you suggest talking to? I know Real Steel have these MerlinF85 heads which are supposed to be ok on Range Rovers. They are around £1200 a pair though.

I suppose you are right though. Maybe a chat with Mark is the way to go. It's just getting hold of the man.

It is thin, but it was the recommended one from an oil specialist. It works well keeping the engine clean. It's one that they suggest TVR's use. Contains something which clings to metal all the time, thus reducing wear on startup. No obvious problems with it but as I havn't opened the engine...

The Merlin heads are a long lead time item. Some people on here have been waiting for 6+ months!

The later engines with composite head gaskets and a symmetrical head bolt regime should not suffer from the same internal gunge that the earlier engines suffered from.

I suspect some other folk on here have bought 'Stage X' heads from various vendors, maybe they'll chip in with their opinions.

Chris.