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Discussion Starter · #1 ·
Decided on settling for a Rover V8 powered Rush as opposed to the Chevrolet small block.

Seems there's a few 3.5 or 3.9 engine cars about, which engine is best in terms of getting the most power from it? Or should I hold out and wait for something with greater capacity?

I know next to nothing about these engines but from what I've seen so far the power output is pretty poor unless they've been tuned. I don't mind spending to get the desired power. Ideally I'd like to keep the engine carburetted, but is fuel injection far better for power? What else is involved in getting the power, just how much does it cost? What parts are required for each specific level of tune and what figures are the result?

Many thanks :)
 

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If you are referring to a Dax Rush stick with a Rover, I have been in a mildly tuned westfield 8 with a 3.5 rover and its is kin fast. All it had was a cam and Holley and it was a beast. Anything heavier would spoil the car and give you more problems with traction than they already have. And believe me they do have trouble putting down 200hp of v8 rover.

Bob
 

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It all depends on what you want to do with the Rush. If you intend to compete in it you should look at the class structure and work out what is allowed and what you can afford. If it is a road car then it'll be pretty quick with a mild cam, ported heads, 4 barrel carb and decent exhaust, and it'll sound good. I won my class in the Blyton Sprint Championship in my MGB GT V8 that was just this spec, apart from the cam being so worn it hardly has any lift.
John
 

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Discussion Starter · #5 ·
If you are referring to a Dax Rush stick with a Rover, I have been in a mildly tuned westfield 8 with a 3.5 rover and its is kin fast. All it had was a cam and Holley and it was a beast. Anything heavier would spoil the car and give you more problems with traction than they already have. And believe me they do have trouble putting down 200hp of v8 rover.

Bob
Thanks for the info Bob :) Agreed it could be a bit of handful but I'm willing to risk it. There's a couple on the Dax forum who've run greater power, it is usable in the right condtions.
 

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Discussion Starter · #6 ·
It all depends on what you want to do with the Rush. If you intend to compete in it you should look at the class structure and work out what is allowed and what you can afford. If it is a road car then it'll be pretty quick with a mild cam, ported heads, 4 barrel carb and decent exhaust, and it'll sound good. I won my class in the Blyton Sprint Championship in my MGB GT V8 that was just this spec, apart from the cam being so worn it hardly has any lift.
John
Thanks John :) Do you know what kind of power that spec produced and what the capacity of the engine was? Also when are forged internals necessary? Thanks :)
 

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You shouldn't need forged internals unless you are doing significant tuning, which is just as well because H beam rods and forged pistons are hugely expensive for RV8 engines by comparison with the same parts for American V8s.
I'd start with a 3.9 motor, these have the same stroke as the 3.5, but a bigger bore, which makes a huge difference to breathing (and so power) as the valves aren't masked by the bore wall. Some porting work, a roadable high lift cam, decent carb and a decent exhaust setup should produce a genuine 200 BHP @ the wheels.
 

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You shouldn't need forged internals unless you are doing significant tuning, which is just as well because H beam rods and forged pistons are hugely expensive for RV8 engines by comparison with the same parts for American V8s.
I'd start with a 3.9 motor, these have the same stroke as the 3.5, but a bigger bore, which makes a huge difference to breathing (and so power) as the valves aren't masked by the bore wall. Some porting work, a roadable high lift cam, decent carb and a decent exhaust setup should produce a genuine 200 BHP @ the wheels.
I agree with Stu, theres no point splashing loads of money into a 3.5 because the best way to get more power is larger capacity. You'll get 10% more from a stock 3.9, so your best bet is to go with that and put a viper hurricane cam or something relatively mild in it, Holley and Performer manifold, tube headers etc like Stu says. This way you're avoiding spending the silly money which you would have to spend on wilder cams, forged internals, stroker kits etc to make serious output from of a Rover v8, costing much more than it would cost to get the same performance and better reliablity from a stock yank v8. Its a law of diminishing returns.
 

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You shouldn't need forged internals unless you are doing significant tuning, which is just as well because H beam rods and forged pistons are hugely expensive for RV8 engines by comparison with the same parts for American V8s.
I'd start with a 3.9 motor, these have the same stroke as the 3.5, but a bigger bore, which makes a huge difference to breathing (and so power) as the valves aren't masked by the bore wall. Some porting work, a roadable high lift cam, decent carb and a decent exhaust setup should produce a genuine 200 BHP @ the wheels.
I agree with Stueee !
The 3.9 would be a good base to build from. Or find a stock 4.6 that you can rebuild. If you want a carb and dissy setup you can fit all that to either lump. Forged pistons for these engines can be had from JE developments, but they can work out around £100 each. Stock rods and pistons will be fine for what you want. I've run my stock 4.6's at stock compression on nitrous to over 400hp with 600 ft/lbs of torque on the drag strip for ages with all stock internals. So a non nitrous 3.9 or 4.6 has lots of power to be found with mods like head skims, decent cam and carb etc as mentioned above. Spend your money on head porting and possibly some head work on the valve spring seats to accept a higher lift from a better cam. An if the budget can stretch to it, adjustable push rods as these will make setting up more simple.

The main thing is to make sure that the block you are building has good liners. If you intend to keep the engine for some time I would bite the bullet and have top hat liners fitted. But this is going to set you back between £800 - £1200 depending on who you have to do the work. Or get the block pressure tested and re bored as required. Or if the budget is really tight just get it pressure tested to make sure the liners are not slipped or leaking. Then you could just glaze bust the bores and fit new rings. You have a lot of options for budget DIY tuning on a Rover V8 for a light car.

I think your car is going to end up around 1000 - 1100kg ?? If you have 200hp at the wheels you will find that will be a lot of fun with a torquey Rover V8 :)
 

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As said before, don't bother with a 3.5 as they're best used as boat anchors. Start with a good used 3.9 or 4.2 (non LPG ). Change the cam and clean the ports and you should easily see around 200bhp from a 3.9. The 4.2 is the best engine
 

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Choose your engine and tuning parts carefully, an engine that produces masses of torque that does well on the quarter mile with an auto box would not be any use on a race circuit. Most of the tuning parts for v8 engines revolve around drag racing that only have to survive 10 second bursts. They are then stripped after a few runs and freshened up, 10 x 2 minute laps of a race track at full throttle would see the contents of most drag engines come through the sump. You will hear loads of folk say they can rev their strokers to 7000+ rpm but again that is for only a few seconds and not for half an hour plus of circuit racing abuse. Go for a max stroke of 3" to keep piston speed in check. Look at some dyno sheets for incite, in a lightweight circuit racer/hill climb car you will need a flat torque curve over a wide rev range, not masses of grunt that goes away after 4000rpm. I would suggest a short stroke screamer in a lightweight car with a manual box. If you need proof of this go and watch the 300/400hp ford v8 289 screaming cobra`s running rings round the 500hp + big block corvettes etc at goodwood.

Bob
 
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