Vacuum Advance pipe

[sgrimshaw]

Having disconnected this Vacuum Advance Pipe, the very thin black piece of plastic pipe, from between the Plenum and the Distributor a few weeks back, I now reckon that my MPG has worsened considerably.

So, I want to reconnect it.

Can I find said piece of pipe - can I bgery.

Is there anything special about the pipe itself? I have some silcon tubing that would appear to fit.

The "Bible" speaks of a one-way unit, but the pipe I took off just had a right-angled connector at each end - I couldn't see any one-way valve. Is this just on Pre-Serpentine's ?

If it is a special pipe, is it a LandRover part - or is it TVR specific.

Thanks in advance,

Simon

[james12345]

Hi Simon.

Not having the bible to hand at work, I can't double check the bit you're seeing (and as well not having the Chim here either, I can't check!) but in past experience going way back to Mini's, the vaccuum advance pipe is just that - a pipe.

The only thing to be wary of would be, I guess, that the silicon pipe doesn't compress when a vaccuum applied to it, or the pipe will take all of the "suck" and not as much will reach the other end, if this makes sense.

James.

[sgrimshaw]

james12345 said:

The only thing to be wary of would be, I guess, that the silicon pipe doesn't compress when a vaccuum applied to it, or the pipe will take all of the "suck" and not as much will reach the other end, if this makes sense. James.

Makes total sense.

The silicon pipe is actually model car fuel-line, so it compresses easily - shan't be using that then.

I think I'll have to spend some more time hunting for the original.

Doh!

Simon

[shpub]

If there is no one way valve then I wouldn't worry. I suspect someone before you changed it.

[sgrimshaw]

Definitely can't find the original pipe.

Anyone know if it's a special part?

Thnx,

Simon

[GreenV8S]

You can get rubber vac hoses with about 5mm wall thickness, these are stiff enough to withstand the vacuum and also hold their shape round corners (rather than kinking). My local motorfactors stocks the stuff, it shouldn't be hard to find. With this sort, you won't need any right-angle connectors. Also, don't bother fitting the 'one way' valve. Plain old pipe works fine.

[ballistic banana]

Maybe a silly question but after taking it out arent you meant to block off one of the ends, Did you do this. May be the reason your MPG has got worse. Although it should get mildly worse anyhow when removing.


MPG and TVR dont mix and shouldnt be worried about anyhow IMHO

BB

[harrow_chim]

I found that my local motor factors had a universal vacuum pipe kit for a couple of quid - probably a lot cheaper than the official part from TVR.
Nick

[sgrimshaw]

ballistic banana said:

Maybe a silly question but after taking it out arent you meant to block off one of the ends, Did you do this. May be the reason your MPG has got worse. Although it should get mildly worse anyhow when removing. MPG and TVR dont mix and shouldnt be worried about anyhow IMHO BB

I blocked off the Plenum end as per the Bible.

MPG isn't usually a concern for me, I even put the fuel on my company fuel card.

It just seemed to have dropped considerably recently though - I was averaging 23-24, now I'm down to 17-18.

Thought I'd rule out the vacuum pipe issue by reinstating it.

Simon

[M@H]

Did you actually gain any performance or anything from removing the pipe...?


Cheers
Matt

[GreenV8S]

It would make no difference to full power, it only serves to improve economy under part load.

[griffter]

sgrimshaw said:

james12345 said: The only thing to be wary of would be, I guess, that the silicon pipe doesn't compress when a vaccuum applied to it, or the pipe will take all of the "suck" and not as much will reach the other end, if this makes sense. James. Makes total sense. The silicon pipe is actually model car fuel-line, so it compresses easily - shan't be using that then. I think I'll have to spend some more time hunting for the original. Doh! Simon

I use silicon vacuum pipe of the type sold for connecting to dumpvalves on turbo cars. Works for me.

[poorpeet]

Thats a big drop in mpg! I doubt the vac pipe is responsible. Could be a combination of the colder weather & a stuck thermosat or temp sensor. If the engine is or thinks its cold then it will run rich so in effect you'll be running with the choke on.
Could also be Duff lambda sensor(s) these would also tend to show up as lumpy idle and or hesitation when giving it some.

Pete

[sgrimshaw]

M@H said:

Did you actually gain any performance or anything from removing the pipe...? Cheers Matt

Seemed to run smoother, I was (am) trying to improve low rev running.

[sgrimshaw]

poorpeet said:

Thats a big drop in mpg! I doubt the vac pipe is responsible. Could be a combination of the colder weather & a stuck thermosat or temp sensor. If the engine is or thinks its cold then it will run rich so in effect you'll be running with the choke on. Could also be Duff lambda sensor(s) these would also tend to show up as lumpy idle and or hesitation when giving it some. Pete

Just want to eliminate it as a cause.

Simon

[iandbeech]

sgrimshaw said:

M@H said: Did you actually gain any performance or anything from removing the pipe...? Cheers Matt Seemed to run smoother, I was (am) trying to improve low rev running.

That`s the reason for removing it and it does do the trick - but I`ve found the fuel "economy" does suffer