max power from. 4 ltr
Discussion
Main issue with the std 400 is the lack of valve pockets in the pistons, restricting cam choice... if you do a complete rebuild the world is your oyster. 
In principle there's no reason why a 4 litre will net any less hp than a bigger capacity motor with the same heads/induction/management, albeit at a higher rpm level... the practical rpm limit for an RV8 - depending on whether you stick with hydraulic lifters, but I'd say not much more than 7,000 before you start to run into other problems - will ultimately set the restriction. Also, a giving cam profile will behave like a 'hairier' one in a smaller capacity engine, so you'll be getting into individual throttles and mapped ignition management territory that much sooner.
I think Morgan got 350 bhp @ 6750 rpm out of a 4 litre RV8 in the BPR GT series in the mid-1990s, stage 2 would have been 400 bhp @ 7,500 but I don't know if they ever got there.
In principle there's no reason why a 4 litre will net any less hp than a bigger capacity motor with the same heads/induction/management, albeit at a higher rpm level... the practical rpm limit for an RV8 - depending on whether you stick with hydraulic lifters, but I'd say not much more than 7,000 before you start to run into other problems - will ultimately set the restriction. Also, a giving cam profile will behave like a 'hairier' one in a smaller capacity engine, so you'll be getting into individual throttles and mapped ignition management territory that much sooner.
I think Morgan got 350 bhp @ 6750 rpm out of a 4 litre RV8 in the BPR GT series in the mid-1990s, stage 2 would have been 400 bhp @ 7,500 but I don't know if they ever got there.
There are more high horsepower ratings boasted of by owners (of any marque) than any honest specialist ever made. 
Of course, the upper limit for Rover bhp can be very high, assuming the car can never be road driven and you accept its being banned from any challenge series worth entering.
The Morgan community adores racing Plus 8s and spends inordinate sums doing so. In the UK, they lean heavily on John Eales (J.E. Development and the founder of J.E. Engineering). His prepared, high revving, 3.9s will put out 280bhp on his flywheel dyno. Of course, the cars become much less than ideal for road driving, but that is a very good figure for a 3.9...ditto for a 4.0. If you study the verified dynographs of other prepares such as V8 Developments, J.E. Engineering etc at that (3.9/4.0) capacity, you will find their figures are the same. The most powerful racing Plus 8, owned by Keith Ahlers, is a er.."4.6", FULLY, race-prepared and running at 367 bhp at the flywheel. [4.6 is the allowable limit for the race series.] There was not a single pence spared.
I am following something very interesting at the moment. A friend of mine is fixating on having the fastest road going Rover V8 ever. The shopping list of components is amazing. It has been assembled over and over, with many tests and experiments for the last 18 months. At the moment, they are trying different camshafts for performance. They have settled on a 5 liter, GEMS based system using two MAS in tandem with a bespoke program that blends the signals for the ECU. The fuel map is also bespoke, being done by Mark Adams. To compliment it, they have modified a R380 gearbox with a bespoke close ratio gear set..(now available from Ashcroft or Elite)
It looks like they will be able to "just" make it over 400 bhp. The total cost, (not including installation which my mate can do himself) will be in excess of 22,000£. And I sourced the Coscast block for him for only 900£ NEW!
I thoroughly enjoy reading how people easily beat this figure with a few local swaps-in.
It is correct that one of the most limiting components on the engine is the stock heads. Been that way since the Buick 215. Staging helps...but minimally. The coolant passages make anything exciting impossible. There are 4 head alternatives;
1. BUICK 360 heads. Tried and true USA route. It is not that there are so great as is, but they have a much grater capacity for improvement than the stock 215, Rover or LR heads.
2. WILDCAT heads. The ones I have seen have not well turned out. The casting is porous.
3. MERLIN heads. I had great hopes for these. But I sadly learned that the bolt holes pierce the head passages. Some can live with that. I can't.
4. TA PERFORMANCE heads. They are sold from one of the Buick 215 companies in the US, but I think they are cast in Australia. They are being tried out, (quietly) by specialists everywhere. Keep your fingers crossed.
+8
Of course, the upper limit for Rover bhp can be very high, assuming the car can never be road driven and you accept its being banned from any challenge series worth entering. The Morgan community adores racing Plus 8s and spends inordinate sums doing so. In the UK, they lean heavily on John Eales (J.E. Development and the founder of J.E. Engineering). His prepared, high revving, 3.9s will put out 280bhp on his flywheel dyno. Of course, the cars become much less than ideal for road driving, but that is a very good figure for a 3.9...ditto for a 4.0. If you study the verified dynographs of other prepares such as V8 Developments, J.E. Engineering etc at that (3.9/4.0) capacity, you will find their figures are the same. The most powerful racing Plus 8, owned by Keith Ahlers, is a er.."4.6", FULLY, race-prepared and running at 367 bhp at the flywheel. [4.6 is the allowable limit for the race series.] There was not a single pence spared.
I am following something very interesting at the moment. A friend of mine is fixating on having the fastest road going Rover V8 ever. The shopping list of components is amazing. It has been assembled over and over, with many tests and experiments for the last 18 months. At the moment, they are trying different camshafts for performance. They have settled on a 5 liter, GEMS based system using two MAS in tandem with a bespoke program that blends the signals for the ECU. The fuel map is also bespoke, being done by Mark Adams. To compliment it, they have modified a R380 gearbox with a bespoke close ratio gear set..(now available from Ashcroft or Elite)
It looks like they will be able to "just" make it over 400 bhp. The total cost, (not including installation which my mate can do himself) will be in excess of 22,000£. And I sourced the Coscast block for him for only 900£ NEW!
I thoroughly enjoy reading how people easily beat this figure with a few local swaps-in.
It is correct that one of the most limiting components on the engine is the stock heads. Been that way since the Buick 215. Staging helps...but minimally. The coolant passages make anything exciting impossible. There are 4 head alternatives;
1. BUICK 360 heads. Tried and true USA route. It is not that there are so great as is, but they have a much grater capacity for improvement than the stock 215, Rover or LR heads.
2. WILDCAT heads. The ones I have seen have not well turned out. The casting is porous.
3. MERLIN heads. I had great hopes for these. But I sadly learned that the bolt holes pierce the head passages. Some can live with that. I can't.
4. TA PERFORMANCE heads. They are sold from one of the Buick 215 companies in the US, but I think they are cast in Australia. They are being tried out, (quietly) by specialists everywhere. Keep your fingers crossed.
+8
Edited by plushuit on Monday 26th December 10:03
plushuit said:
I am following something very interesting at the moment. A friend of mine is fixating on having the fastest road going Rover V8 ever. The shopping list is amazing. It has been assembly, with many tests and experiments for the last 18 months. At the moment, they are trying different camshafts for performance. They have settled on 5 liter, GEMS based system using two MAS in tandem with a bespoke program that blends the signals for the ECU. The fuel map is also bespoke, being done by Mark Adams.
Like your opnening sentence too, more than a whiff of thruth in there
I do admire the pain your putting your self through to improve this engine .i personally think its crazy to spend 22,000£ on this project .i could understand it if you have to keep the engine in the car ,such as classic Rally cars (pinto engines making 270hp costing 30k)
Why not put the engine to bed a buy a different V8! there is so many modern V8`s to use with 400hp plus and then spend the money on fitting the engine,exhaust ,chassis etc ..The LS is cheap to buy from a crate and it even comes with fuel management..
Move on !
I thought Coscast were crap
Why not put the engine to bed a buy a different V8! there is so many modern V8`s to use with 400hp plus and then spend the money on fitting the engine,exhaust ,chassis etc ..The LS is cheap to buy from a crate and it even comes with fuel management..
Move on !
I thought Coscast were crap
Edited by SILICONEKID340HP on Sunday 25th December 22:58
I'm surprised to see this question from the OP given the "expert" technical advice he has access to. Unless of course someone other than expected is going to be building the engine.
Nothing personal Graham but we've heard the triumphant return to form story before haven't we ?
Awaiting the next instalment of the PR exercise with great interest....
Honestly, nothing personal, just a wry smile
Nothing personal Graham but we've heard the triumphant return to form story before haven't we ?
Awaiting the next instalment of the PR exercise with great interest....
Honestly, nothing personal, just a wry smile
Not a problem mate, I'm just interested to see what various people have achieved in the real world.
Before I decide to try and put a quick 4ltr together
Or the easier route of 5 ltr maybe. I do like the revability of the 4 ltr.
5ltrs can sometimes make big power but still be quite lazy to rev.
Or maybe I'll do a topgear and bang in a couple of batteries and an electric motor lol
Before I decide to try and put a quick 4ltr together
Or the easier route of 5 ltr maybe. I do like the revability of the 4 ltr.
5ltrs can sometimes make big power but still be quite lazy to rev.
Or maybe I'll do a topgear and bang in a couple of batteries and an electric motor lol
Graham said:
Not a problem mate, I'm just interested to see what various people have achieved in the real world.
Before I decide to try and put a quick 4ltr together
Or the easier route of 5 ltr maybe. I do like the revability of the 4 ltr.
5ltrs can sometimes make big power but still be quite lazy to rev.
Or maybe I'll do a topgear and bang in a couple of batteries and an electric motor lol
I know of a 5.0, newly rebuilt by a builder you trust, that you're welcome to buy. He assured me it was a cracker lol !Before I decide to try and put a quick 4ltr together
Or the easier route of 5 ltr maybe. I do like the revability of the 4 ltr.
5ltrs can sometimes make big power but still be quite lazy to rev.
Or maybe I'll do a topgear and bang in a couple of batteries and an electric motor lol
I don't know as much about the RV8 as many of you on here, but if high hp is what you're looking for youve got to shift a lot of air so you need the inlet valve and seat working as well as you can .. so read pumaracing's excellent report in the 3/5/7 angle seat thread from brummmie .. but also I would expect (though don't know for sure) that youd want to be moving the bore as far from the inlet valve as possible to unshroud it higher valve lifts .. so a large bore short stroke engine would presumably be what you'd be working towards ..?
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