RS2 Jenvey Manifold

[Westyfield2]

Bit of a random question but anyways...

Looking at photos of the JMS RS2, there seems to be two versions. I don't mean the RS2 Extra (the longer one that can have issues with radiator/slam panel/grill). But rather I mean the regular RS2.

If you look at the photos of them fitted, some of them are made of two parts. There's the Jenvey base manifold, which bolts to a manifold that looks just like a hollowed out set of ITBs , and then the carbon inlet plenum.
But on others (newer ones?) the Jenvey base manifold and the part two manifold (what I call the hollowed out set of ITBs) are merged together into one piece.

Anyone got any info on what/when/why the changeover was? Does the two piece design have a longer length than the single piece design?

 

[Westyfield2]

The original two piece design with the join clearly visible:

The single piece design:

Wondering if the length changed between the two designs with the removal of the join, making it an "RS2 extra half" or something?

 

[cs_dave]

The extra is the spacer in the middle it's what I have waiting to fit on my 182

 

[aucky]

Iirc the extra was an experiment but it required the slam panel to be cut so they didn't run with it. Or something like that.

 

[Sir_Dave]

From memory, re: your pictures, the first version was two "off the shelf" parts spliced together, whereas the second was after they had a custom part made by jenvey from their cad designs.

The inards were pretty much the same iirc, it was just a change in manufacturing.

The rs2 extra was an entirely different/one off project.

 

[Westyfield2]

From memory, re: your pictures, the first version was two "off the shelf" parts spliced together, whereas the second was after they had a custom part made by jenvey from their cad designs.

The inards were pretty much the same iirc, it was just a change in manufacturing.

Intriguing, thanks.

What I don't get is that we always said it was a Jenvey base manifold... but looking at their catalogue I can't see anything that matches. The Jenvey base manifold (for ITB kits etc) doesn't have the fuel injectors! http://www.jenvey.co.uk/products2/manifold/manifold-renault-172-f4r-sf-mr23

 

[MicKPM]

As above, the original batch were a Jenvey F4R manifold with spacers pieces to add the required length. The second gen had a custom manifold cast but I don't believe there's much between the two types when it comes to power results. The only thing I don't like about the first gen is the injector ports as they're JB welded in place and can snap off (I had it happen on mine) and had to fabricate a proper fuel rail mounting solution to save it happening again.

This isn't an issue with he second get either.

 

[Chambers_RS]

Here's mine all in bits for anyone interested.

 

[Westyfield2]

As above, the original batch were a Jenvey F4R manifold with spacers pieces to add the required length. The second gen had a custom manifold cast but I don't believe there's much between the two types when it comes to power results. The only thing I don't like about the first gen is the injector ports as they're JB welded in place and can snap off (I had it happen on mine) and had to fabricate a proper fuel rail mounting solution to save it happening again.

This isn't an issue with he second get either.

Thanks for the info!
So I guess it was the usual Jenvey MR23 Manifold (75mm length), with injector pockets welded in, and spacers of I’d guess about 50mm length. I don’t suppose anyone still has a original RS2 around to actually measure? Just intrigued to know if there was any change in manifold length between the original two piece and the later single piece.

When making it out of two pieces, I wonder why JMS assembled it that way round? Obviously they wouldn’t want anything too extreme like remote fuel injectors out of the airhorns… but I’d have thought moving the injectors a bit closer to the plenum rather than the head could help with fuel mixing?

Here's mine all in bits for anyone interested.

Always <3 carbon trumpets!

 

[NB_Hamster]

I've got the same set up as @Chambers_RS and was wondering what type of gasket there should be between this manifold and the head. Doesn't look like there's anything in at the moment (unless it's o-rings).

Also got the RS2 Xtra extensions to go on when I sort out a radiator and bonnet catches. I'm assuming there should be o-rings to seal this onto the manifold too.

 

[Chambers_RS]

I've got the same set up as @Chambers_RS and was wondering what type of gasket there should be between this manifold and the head. Doesn't look like there's anything in at the moment (unless it's o-rings).

Also got the RS2 Xtra extensions to go on when I sort out a radiator and bonnet catches. I'm assuming there should be o-rings to seal this onto the manifold too.

Don't wanna sell the extensions do you?

 

[NB_Hamster]

Don't wanna sell the extensions do you?

Not up for selling them at the moment I'm afraid.
Am pretty keen to get them on and the cam timing set up. The additional torque should be pretty useful for hillclimbs.

If I change my mind I'll let you know.