Twin intake plenum

[DaveEFI]

A TP setup has just gone for over 800 quid on Ebay. If it is so good, why wasn't it included in later versions of the engine?

Discuss.

[CastleMGBV8]

Dave,

Was only produced for a short period for homologation purposes, there was no real advantage to using it on the road cars as the power increase was at the top end but for racing they managed to squeeze over 300BHP out of the 3.5 even with the restrictive group A regs.

Kevin.

[K4000JB]

Just my experience when fitting the Twin plenum to my engine max torque came straight in from 2000rpm. it made the same top end power but at that time was running lean. just my experience.
I know what you mean about these rare parts a set of grp A rockers went for £300 recently incredible really.

[ramon alban]

If it is so good, why wasn't it included in later versions of the engine?

It was and is good, intended to encourage future development of an "off the shelf model" for competitive racing.

Why not added to later models? Probably because the Rover marketing and sales organization had no current/future interest in putting the V8 RR/LR/Classic/etc range of cars into homologation for production car competitions.

They had better options available in terms of fuel/ignition management, capacity, etc to get more active horses out of road-going engines and increasingly restrictive emission rules.

On the other hand, what would the, then, best competitive racing stables have been able to do with a TP version of the later engines given a similarly free hand on how to breath and fuel them?

Indeed, one might say that were it not for the TP, those racing developments would never have happened, future engine development subsequently delayed, and maybe Rover would have folded years before it actully did. Most such enhancements used to come from the race track?

So you see, the TP stands proud of its place in history due to being at the root of all subsequent RV8 improvements.

Another weird thing, in RV8/SD1 circles it seems non-TP owners readily draw conclusions of despair about the TP, whereas the TP owners just grin a lot.

I grin a lot, naturally, but had not realised until today, its prolly all down to the TP.

They polish up well too!

[DaveEFI]

How many races has your car been in, Ramon?

[Coops]

mines got one too

[DaveEFI]

mines got one too

And an air filter sucking in all that hot air?

[spend]

And an air filter sucking in all that hot air?

What Hot Air? its carefully insulated by a plastic bag

[Coops]

And an air filter sucking in all that hot air?

What Hot Air? its carefully insulated by a plastic bag

only when in traffic,
otherwise the cold air duct pipe from the front grill solves that,

[Wotland]

When Rover stopped the production of SD1, Eales bought the tool to product the twin throttle plenum.

[DaveEFI]

When Rover stopped the production of SD1, Eales bought the tool to product the twin throttle plenum.

Interesting - did wonder if Lotus had kept the rights or something.

What did Eales do with it - don't remember seeing aftermarket ones around much.

[Cobratone]

What I've never understood is that most of the twin plenums I've seen still go down to a small inlet air filter destroying the benefit of the increased throttle size, why do people do that

[K4000JB]

What I've never understood is that most of the twin plenums I've seen still go down to a small inlet air filter destroying the benefit of the increased throttle size, why do people do that

I think this is mainly due to the AFM still being used by most, I noticed that the engine still ran weak at the top end when I fitted mine to te standard setup, so I would say that it was flowing more than enough for the standard map, another thing I noticed was how biased the standard 'y' piece is to the rear cylinders and is more restrictive than the AFM.
just my experience I hope its of use