Boosted V8.....

This is mostly out of curiosity, but why isnt boosting the 3.5 (or any rover v8) that done often. Ive seen a couple of boosted 3.5 Rover SD1's making good power 'reliably'.
As everyone knows making a rover v8 powerful (300hp ish) is very very expensive. But surely boosting one (turbo seems most viable for low end torque etc) is possible and surely cheaper than buying big cam, high cr pistons, ported heads, efi, stroker kits etc. A pair of small turbos which would spool hard at 2k and make good boost surely would be great for off road applications.
Of course running 3-4 psi would be fine but wouldnt have that significant gains and wouldnt need an intercooler.
I saw an SD1 running a single turbo (intercooled) on a stock bottom end with an okay cam putting 350hp and 400 ish lb to the wheels at 11 psi or something, and it did some miles on that setup.
I feel like there are logical reasons for not doing it, but in my mind a pair of small modern ball bearing turbos with rover v8 manifolds (they exist, £350 ish) a decent cam, intercooler and modified SU carbs to run blow through or just on efi would work great, good low end torque and long strong power curve and probs a good 300hp 350lb at the wheels (assuming the drivetrain would hold). I mean they already have really low compression ratios and just stick a bigger head gasket in.
The total setup would be 2k ish and seeing as what some people spend to get 300hp from a rv8 that seems great?
This is all me making assumptions and i would love to hear any ideas and issues you guys think of, i assume there is one big flaw i am missing or surely people would do this.
(also i know janspeed did some turbo kits for a bit but they dont seems to really be arround much)

I believe the SD1 Vitesse put out 190bhp using a similar EFI set-up to the Oct '85 -> RRC, but probably running a different cam etc.
There was a Janspeed for sale last year but I can't remember where I saw the advert. Thing is with a 2 tonne shed it's not so much power you want as grunt, which is where a turbo would come in handy I guess.

considering the larger bore blocks are prone for cracking as it is , a turbo and higher temps isnt going to help

It is done. But is still pricey tbh and getting the bits are probably easier said than done. Turbos also suffer lag and are more typically mid range power for petrol motors.

However I’d love some links to some of the items you list in your op please.

300bhp/ton said:

It is done. But is still pricey tbh and getting the bits are probably easier said than done. Turbos also suffer lag and are more typically mid range power for petrol motors.

However I’d love some links to some of the items you list in your op please.

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How to do a blow through SU https://www.mgexp.com/article/how-to-blow-through-an-su.html
Manifold (Cant find the ones i originally did but) http://www.boostperformance.co.uk/rover_v8.html -£430 for the pair But either a wastegate would be needed to be added or get a turbo with a wastegate already on it.
For a twin turbo intercooler just look on ebay, you can find them for arround £100.
Blow off valve, would need an up to 20 psi one -£150 for a genuine one.
With turbo setups you dont want too wild a cam, very mild one (3.9 cam - £230, can find them for much less) http://www.v8tuner.co.uk/product.php?id=970
For a bit of a less mild setup- http://www.v8tuner.co.uk/product.php?id=693
For turbos it is completely up to you, what you want performance wise and what you are willing to spend. But as i said a pair of small twims i imagine i best for off road, so a junkyard pair of a newer 1.8 turbo car, just find two the same and fit them. Or if willing to spend £££ get a pair of garrett turbos.

jamesmartin said:

considering the larger bore blocks are prone for cracking as it is , a turbo and higher temps isnt going to help

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Fair enough, but surely on a 3.5 on mild boost and being made to run a little rich under boost and you would be fine.

Burtie2904 said:

Fair enough, but surely on a 3.5 on mild boost and being made to run a little rich under boost and you would be fine.

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yes a 3.5 is a different matter

Looked at your link Burtie but surely nobody is going to pay that money, especially if (like myself) they also have to fork out for the labour costs involved, just to add 5 to 8 bhp. Maybe the kit increases the torque or at least changes the curve.
I notice the cam for the carb version of the 3.5 has a different profile to the 3.5efi & wonder why. What would the effect be if this cam was used on the efi engine ?

Its the rest of the drivetrain i would worry about

Gearbox would probably shyte itself with the extra power going through it.

Supercharge it.

Both supercharger and turbo kits are available for the Rover V8 powered TVRs, they make good reliable power too

norseman said:

Looked at your link Burtie but surely nobody is going to pay that money, especially if (like myself) they also have to fork out for the labour costs involved, just to add 5 to 8 bhp. Maybe the kit increases the torque or at least changes the curve.
I notice the cam for the carb version of the 3.5 has a different profile to the 3.5efi & wonder why. What would the effect be if this cam was used on the efi engine ?

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I think you have misunderstood, with all mentioned, cam and turbo setup it would be a near 200hp 200lb increase over stock. And I agree I do find it curious how the cams have different profiles for efi models vs carb models.

Henry_b said:

Its the rest of the drivetrain i would worry about

Gearbox would probably shyte itself with the extra power going through it.

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Yeah haha i would be interested to see where the limit is, anyone heard of people breaking drivelines after adding power ? And if so what sort of specs on the engine

Moron said:

Both supercharger and turbo kits are available for the Rover V8 powered TVRs, they make good reliable power too

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I looked (probably not enough) and found 1 or two, I seems to think doing it now kit would be wayyyy cheaper and the fact that few are based on the smaller tvr rover engines, rather the bigger blocks.

Burtie2904 said:

I agree I do find it curious how the cams have different profiles for efi models vs carb models.

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Another thing as well, I've read / heard that the famous exhaust 'woofle' is more pronounced on the carb versions. Can't understand why as the firing order is the same & a fuel/air mixture is present regardless of whether it's sucked in or the fuel element is squirted.
Has anyone else pondered the question, or am I just loosing it in my old age

Burtie2904 said:

I think you have misunderstood, with all mentioned, cam and turbo setup it would be a near 200hp 200lb increase over stock. And I agree I do find it curious how the cams have different profiles for efi models vs carb models.

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I suspect the biggest issue is still cost. And the fact that while the links you supplied are very interesting, they appear to be very much a DIY and R&D solutions.


In the off road world, I doubt many are spending BIG money for huge HP n/a setups. And those that do are probably competing, where forced induction petrol engines are sometimes not allowed anyway.


As a multiple RV8 owner I find the appeal of turbo conversions quite interesting. But tbh I can’t see it being a cheap option and get too greedy and you’ll be looking at a full rebuild and forged internals too. And at this price point you have to wonder if swapping in a Chevy LS1 might be a cheaper option.