Best way of obtaining more power?

[Rover 3500S]

Hi! I'm looking to build myself some kind of Rover V8-powered car (possibly a P6) for mixed road/track use and wondered how to get the most power out of the engine. First, what's the biggest displacement the engine has ever been boosted to? Second, to supercharge or to turbocharge? If turbos, one, two or four? How much power would it be possible to get from the biggest variant of the RV8?

[topcatcustom]

In one of the RV8 tuning books there is a nice picture and dyno sheet of a 750bhp 5l RV8 (Wildcat) that is NA. What I'm saying is depending on your budget you could get anything!

The reason you dont see many massive bhp RV8's is because they cost so much more to tune than other V8's, £2k will get you in the region of 300bhp with a Rover, maybe double that with an american V8.

[Rover 3500S]

In one of the RV8 tuning books there is a nice picture and dyno sheet of a 750bhp 5l RV8 (Wildcat) that is NA. What I'm saying is depending on your budget you could get anything!

The reason you dont see many massive bhp RV8's is because they cost so much more to tune than other V8's, £2k will get you in the region of 300bhp with a Rover, maybe double that with an American V8.

Right. Still, American V8s tend to be iron-blocked, whereas the Rover (yes, I know all about its origins) is aluminium. I'd like to stick to the 'correct' engine for my 70s BL classic if at all possible - I don't want to go shoehorning a Chevy 350 into a P6! So, how much is possible from the Rover V8 if your budget is unlimited? Would you recommend NA or SC over each other? I'm not entirely sure about turbos, I don't want loads of lag. I'd like - ideally - to be able to break 200mph, which is M5/XFR territory. Hell, though, I'd like to see if I could get in a Koenigsegg 4.4 litre twin turbo - 850bhp, or 900 on bio-ethanol! That would get a P6 up to almost 250, by my extremely rough reckoning!

[topcatcustom]

Not sure if your P6 aerodynamics quite equal the Koenigsegg

To be honest I cant say what power you could get, someone will though! If you spend thousands bullet proofing the lump though who really knows?! I like superchargers over turbos, but personal preferance!!!

[kiwicar]

Hi
if you stick with a 3.5 or 3.9 block and standard heads (home ported)with standard pistons and SU carbs you should be able to get around 200 to 210 bhp in road drivable form for about £1200 finnished and running plus a session on a rolling road to set it up will be about another £350 or so.
want to go more?
A 4.6 top hat linered block, machined and ready for assembly is about £850 to £1000, a set of stage 3 heads are about another £750 to £1000 depending on who does them and exact spec, bored out fuel injection manifold and aftermarket EFI with a twin throttle plenum will add about another £8-900 compleet and will give you 260 to 280 BHP.
to build a 5.0 ish engine and make the expence worth while is about £750 for the crank machined, 350 for the rods, machined and ready, decent pistons (Ian Stewart has found some nice ford modular pistons that look good, about £250 to 280 imported and a set of real steel heads are £1400 should see 330 to 350 bhp. want more? roller cam conversion £750 bottom end brace £150 to £250 throttle bodies and manifold £750 if you adapt bike ones about £1500 if you use jenveys roller rockers are about 450 a set suitable valve springs about £300. and add another 40 bhp a set of wild cat heads around £2500.
Addapting chevy pistons to get a few more ccs will add about another £250 to this and add a little more to the total output.
A 5.3 LS makes 270 bhp out the box and can do 350 with a cam change and will set you back about £2500 imported. How badly to you want a rover engine ?
Mike

[kiwicar]

You mention forced induction so here we go.
If you want to go twin turbo, or single turbo, it is really a case of what space you have then it all depends on how much power you want. If you are aiming for modest output then a basic build of standard pistons, standard rods but shotpeened and ARP bolts, flowed heads but with large exhaust valves and with a 9:1 CR and about 6 to 8 Lbs boost should see you in the region of £1350 for the engine plus the turbo kit, say £2500 by you have all the manifolds, intercooler and brackets, £100 for a second hand injection manifold £150 for a set of injectors and about £450 for an ECU and bits to go with it. Knock off about £200 if it is single turbo. Super charging is more dificult to price as it depends what you can find second hand and at what cost and how many brackets you can make youself, though once you have a supercharger you should budget £850 for intercooler, belts and plumbing and £350 for brackets, but be prepared to add alot to that!
That should see 270 to 320 bhp depending on exactly what you end up with.
Want to go over 320 bhp you will need better pistons, better rods, probably a forged crank (certainly over 500bhp) much the same as the NA build. Getting the bottom end stable will be a big issue, as although you can stay with the 3.5 block to about 450 BHP you will need to brace the bottom end very effectivly after that, If you go 4.6 block for the cross bolts you then have to sort out the liner issue, true it gets you more capacity but at a price. really the rover is cheep power up to 200 to 210 BHP depending on your ability to build it well then quickly gets expensive with every 20 bhp costing you about twice as much as the last after that also get over about 300 bhp (350 forced induction in any form and it is going to be delicate and need alot of maintaining, over 340 (450 forced induction) and you have an engine that will wreck itself given the slightest ill treatment, for the money it costs to build a rover to make 250 bhp you can get 420 out of a SBC or 480 out of an LS chevy and both are just starting.
Best of luck
Mike

[ian.stewart]

If you were to go with a P6, I would imagine there will be a few problems,
1, they never were a popular circuit car, and because of this suspension upgrades will be probably hard to find,
2, Brakes. obviously they can be built up to a fast road spec, but would probaby be expensive, and as for the rears,!!! [and dont forget, the FIRST RULE of going faster, is upgrading the brakes,]
3 They weigh a not much less than a super tanker,
4 They ROT,
5, overhung back arches limit the tire size, and if you have intentions of putting 350hp+ thru 195 series tires will be interesting and is the back suspension up to it,
Personally I would love to build a quick P6, I think Turbos would be a non starter due to space restrictions, even fitting a supercharger would be a challenge, probably the easiest way would be run a serp engine, dump all the non esential bits, and drive the charger off the serp, how to fit the needed charge cooler and piping would be interesting.
possibly the American fad at the moment of fitting Turbos at the rear of the car may work, but would produce a really laggy engine, but with all the piping back to the engine if done correctly can be made to work as an air to air charge cooler.
I thing there are loads of glass replacement panels bonnet, front and rear wings, front vallance, would all help with the search for performance, then as an option you could build a Bill Shaw replica, then you can fit 10" rims all round, somebody has the molds, either in Germany or Oz
IMO, The best option I would think is a BIG capacity engine on injection of some sorts, and have a 300+hp NA engine, bolted onto a Toyota Supra box, or even a Tremec T56

[Rover 3500S]

Hi
A 5.5 LS makes 270 bhp out the box and can do 350 with a cam change and will set you back about £2500 imported. How badly to you want a rover engine ?
Mike

I really, really want to keep the car as authentically Rover as possible... but if there's a better alternative, I'll listen. I'm starting to think that a Jag 4.2/5.0 supercharged or a BMW S65 (4.0L, current M3) or an S62 (5.0L, old E39 M5) or possibly even an Audi 4.2L might make more sense. Good as the GM LS engine undoubtedly is, I'd choose the Jag engine. On the other hand, it still wouldn't be a Rover engine... if it would be possible to get the kind of power I want from what Richard Hammond described as "The Queen Mother of car engines", then I will.

Also, here's another idea: could you fit a Rolls-Royce/Bentley 6.2/6.75 into a P6? Just a thought...

[Rover 3500S]

If you were to go with a P6, I would imagine there will be a few problems,
1, they never were a popular circuit car, and because of this suspension upgrades will be probably hard to find,
2, Brakes. obviously they can be built up to a fast road spec, but would probaby be expensive, and as for the rears,!!! [and dont forget, the FIRST RULE of going faster, is upgrading the brakes,]
3 They weigh a not much less than a super tanker,
4 They ROT,
5, overhung back arches limit the tire size, and if you have intentions of putting 350hp+ thru 195 series tires will be interesting and is the back suspension up to it,
Personally I would love to build a quick P6, I think Turbos would be a non starter due to space restrictions, even fitting a supercharger would be a challenge, probably the easiest way would be run a serp engine, dump all the non essential bits, and drive the charger off the serp, how to fit the needed charge cooler and piping would be interesting.
possibly the American fad at the moment of fitting Turbos at the rear of the car may work, but would produce a really laggy engine, but with all the piping back to the engine if done correctly can be made to work as an air to air charge cooler.
I thing there are loads of glass replacement panels bonnet, front and rear wings, front vallance, would all help with the search for performance, then as an option you could build a Bill Shaw replica, then you can fit 10" rims all round, somebody has the molds, either in Germany or Oz
IMO, The best option I would think is a BIG capacity engine on injection of some sorts, and have a 300+hp NA engine, bolted onto a Toyota Supra box, or even a Tremec T56

I'd be happy to muck about with the suspension myself, or pay the professionals to do it for me (Lotus 3500, anyone?). The P6 is quite light by today's standards - a BMW M3 weighs about 1550kg, a P6 only about 1300kg. Obviously, better brakes are essential - could one fit an Alfa Romeo rear transaxle, perhaps? All Alfas up to the 75 had a De Dion rear end with inboard discs like the P6, but with the gearbox at the back... I might be prepared to muck about with wheelarches, too, perhaps getting rid of the overhang. I have seen a P6 with fat wheels, though - I'm not quite sure how it was done, though. It's dark grey, has fat (16 or 17 inch, 225-section, I think) wheels with twelve spokes, in six pairs, with a narrower PCD than original (spacers were used, apparently), and has a race-prepared 4.2 turbo engine with Megasquirt, whatever that is. There are a few low-quality clips of the build on YouTube, plus a photo on Flickr - I'll try to find them for you.

[Boosted LS1]

Your engine has weak slotted pistons in it, they'll handle 5-6 psi ok though but not a lot more. Next blown option is a rebore and forged pistons, this can take 15 psi depending on your c/r


Or, you can use a stock crossbolted 4.6 that hasn't got coolant issues. The internal and block are quite strong so this will be a very good option. Leave it all alone and give it 7-10 psi and it should be ok.

After this you're into the realms of custom builds.

[Rover 3500S]

Your engine has weak slotted pistons in it, they'll handle 5-6 psi ok though but not a lot more. Next blown option is a rebore and forged pistons, this can take 15 psi depending on your c/r


Or, you can use a stock crossbolted 4.6 that hasn't got coolant issues. The internal and block are quite strong so this will be a very good option. Leave it all alone and give it 7-10 psi and it should be ok.

After this you're into the realms of custom builds.

I'd kind of assumed an expensive custom build - this is a budget-unlimited dream I'm talking about here.

[Boosted LS1]

I'm building a similar dream right now with some input from Spend. Crossbolted 96mm top hat linered block with an 82mm stroke large journal crank fitted with a set of carrillo rods on 2" pins. It so it displaces nearly 4.8 litres. Top end is tvr as is the chassis. A nice low c/r has been specced from custom pistons and a target of 600 hp minimum is expected I haven't done the flow charts yet but it'll probably be a pair of GT28's as they'll make 600 hp'ish.

[sowen]

This sounds very similar to what I'm currently building. I have a 2000, which I've retrofitted the v8 specific parts into the engine bay, and will begin building a supercharged 3.9 once the car is on the road and out of the garage.

I'd be happy to muck about with the suspension myself, or pay the professionals to do it for me (Lotus 3500, anyone?). The P6 is quite light by today's standards - a BMW M3 weighs about 1550kg, a P6 only about 1300kg. Obviously, better brakes are essential - could one fit an Alfa Romeo rear transaxle, perhaps? All Alfas up to the 75 had a De Dion rear end with inboard discs like the P6, but with the gearbox at the back... I might be prepared to muck about with wheelarches, too, perhaps getting rid of the overhang. I have seen a P6 with fat wheels, though - I'm not quite sure how it was done, though. It's dark grey, has fat (16 or 17 inch, 225-section, I think) wheels with twelve spokes, in six pairs, with a narrower PCD than original (spacers were used, apparently), and has a race-prepared 4.2 turbo engine with Megasquirt, whatever that is. There are a few low-quality clips of the build on YouTube, plus a photo on Flickr - I'll try to find them for you.

I have 225 tyres on the rear of mine, fitted to chevy 1/2 ton truck wheels, with the centres re-welded to fit behind the wheelarches, very sleeper style.

As for the axle, I've built a hybrid rover/jaguar de dion axle. If you're interested, I can post pictures up.

The car is not on the road yet, so I can't say how well it will perform with these modifications, being the main reason why it will remain a 4 cylinder until the engine is built up and I'm 100% happy that my workmanship will hold together.

[JC.]

3 They weigh a not much less than a super tanker,

Disagree. I used to have one. 1.3 tons is hardly THAT heavey. Certainly doesn't feel like a heavey car to drive anyway...

[Rover 3500S]

http://farm3.static.flickr.com/2568/371 ... 2e50_o.jpg is the 4.2 turbo I mentioned!

Videos at http://www.youtube.com/watch?v=M0JYE0Diwhw and http://www.youtube.com/watch?v=e82ZMRr_TBc