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[peter the butcher]

was having a disscusion with a friend, and we were talking about my old favourite beastie, a Rover SD! Vitesse 3.5 twin plenum. I had the fuel injection removed, and replaced with a 4 barrel Holley carb, stage 3 heads and the normal cam. On the bench it got to 260 BHP , not to bad, a 60 increase on standard. Are the any still out there tho? not seen one for a long time now

Peter

[peter the butcher]

oh, forgot, it also had a stainless sports exhaust from tubular manifolds to the tail pipe, nothing fancy, just a single tailpipe, but sounded marvelous on full chat in a tunnel or underground carpark

[Marks DTM Calib]

Thats a rare power increase for the asthmatic Rover V8 and as good as many TVR's with greater cc.

The fuel injection is capable of giving more power than the carb to

[Elite Pete]

I had a TR7 convertible with a 3.9 V8, which had been tinkered with, that also had a 4 barrel holley, Offenhauser manifold, 4 branch manifolds and gave me a stiffy whenever I thrashed it

[Sir Tigger KC]

I had a TR7 convertible with a 3.9 V8, which had been tinkered with, that also had a 4 barrel holley, Offenhauser manifold, 4 branch manifolds and gave me a stiffy whenever I thrashed it

Take it that was a few years ago then Pete? 

[Elite Pete]

I had a TR7 convertible with a 3.9 V8, which had been tinkered with, that also had a 4 barrel holley, Offenhauser manifold, 4 branch manifolds and gave me a stiffy whenever I thrashed it

Take it that was a few years ago then Pete? 

It's been a while since i've seen the old boy

[YZ250]

was having a disscusion with a friend, and we were talking about my old favourite beastie, a Rover SD! Vitesse 3.5 twin plenum. I had the fuel injection removed, and replaced with a 4 barrel Holley carb, stage 3 heads and the normal cam. On the bench it got to 260 BHP , not to bad, a 60 increase on standard. Are the any still out there tho? not seen one for a long time now

Peter

I had a Moonraker Blue 3.5 Vitesse twin plenum for about five years. 

I know of two fully restored SD1's. One is a 3.5 Vitesse TP and the other is a 3.5S.  When I say fully restored, I mean stripped right down to the bare chassis with all panels removed to leave just the framework. They have both spent in excess of £12K rebuilding these cars. 
Panels can be sourced from India I believe. Although I wouldn't do it, you've got to admire the dedication of people that do this. 

[Marks DTM Calib]

Its interesting to note that the twin plenum (which is actualy a single plenum with twin throttles) added pretty much no agin to engine output when compared to the Vitesse power plant.

With some tuning the setup becomes more useful but in reality, the throttle was never the big restriction.

Rover V8's have a major issue and that is the head design, porting etc helps but bottom line is that for big gains you need new heads (there are now some available!).

If you consider a 3.5 with stage 3 heads which have improved gas flow and slightly larger valves (gets you close to the original Buick heads ability before Rover buggered the design up), throw in a typhoon or hurricane cam (or similar e.g. 285 although the racey ones make them idle VERY badly), toughened timing chain, rhodes lifters and the like then your still not reaching the point where the throttle is limiting and interestingly, from my experience, these rarely see above 230-240 on a dyno with EFi.

[omega3000]

Still a few around on the auction sites and some tasty ones that have had a lot spent on them ... love these cars but think i would shove a chev v8 in it and be done with it ..

[peter the butcher]

I had a TR7 convertible with a 3.9 V8, which had been tinkered with, that also had a 4 barrel holley, Offenhauser manifold, 4 branch manifolds and gave me a stiffy whenever I thrashed it

Take it that was a few years ago then Pete? 

yeah, it was about 8 years since

[peter the butcher]

Its interesting to note that the twin plenum (which is actualy a single plenum with twin throttles) added pretty much no agin to engine output when compared to the Vitesse power plant.

With some tuning the setup becomes more useful but in reality, the throttle was never the big restriction.

Rover V8's have a major issue and that is the head design, porting etc helps but bottom line is that for big gains you need new heads (there are now some available!).

If you consider a 3.5 with stage 3 heads which have improved gas flow and slightly larger valves (gets you close to the original Buick heads ability before Rover buggered the design up), throw in a typhoon or hurricane cam (or similar e.g. 285 although the racey ones make them idle VERY badly), toughened timing chain, rhodes lifters and the like then your still not reaching the point where the throttle is limiting and interestingly, from my experience, these rarely see above 230-240 on a dyno with EFi.

that figure was given to me by the engine people up here in doncaster, when I went to see what they had done, I personally never had it tested in the car.
just a note tho, I was thinking at the time of putting a "blower" on it along with a "fast road cam" that Rimmer Bros had in there brochure, but like a lot of things then, money ran out and it was not achieved

Peter

[Marks DTM Calib]

If it had the heads and a standard cam then it would be barely over 210bhp at best as its the cam that unlocks the head work.

The 3.5 cam as fitted is pretty poor (the twin plenum didn't get anything special here) to the point that even the 3.9 Efi cam gives an improvement.

[dbug]

Remember stuffing one of these V8s into an MGB many years ago (before MG offered a V8 version), had flowed, balanced and ported heads, a "half-race" cam, holley carb - around 225 bhp.

[Elite Pete]

It wasn't all about the power in my TR7. Get the roof off and with it being low with stiff suspension and the noise of the V8 it felt like you were doing 200mph

[dbug]

It wasn't all about the power in my TR7. Get the roof off and with it being low with stiff suspension and the noise of the V8 it felt like you were doing 200mph

Was a shame the TR7 didn't follow Harris Mann's original designs which were stunning - got changed, for the worse, due to US market needs.  Originally designed to be fitted with a V8, and again finances dictated a 4 pot, until the emergence of the TR8, and various Grinnalls.