Ph1 172 throttle body

[essexdon]

Hi people, just bought a ph1 172. It has a cheap cone filter fitted to it and am looking at getting a standard air box fitted soon. But there seems to be a hole on the body that seems to missing a pipe to something else. I am just wondering if anyone could point out what this is for or if it will make much difference if its open or closed off. Here are some pics of the hole. Cheers

 

[Rob]

If it's going to be open like that, rather than returning to the induction elbow like it does as standard, best thing to do it buy a bit of silicone pipe and a motorcross filter to put on the end off of ebay.

 

[essexdon]

Thanks, so do you know what it does?

 

[Martin_172]

it goes into the rear of the engine/inlet manifold cant remember from memory, just get a hose from someone breaking a car or just get a length of hose to replace it yourself

 

[essexdon]

thanks will it make much diff thou?

 

[Martin_172]

im not sure if its something to do with idle control or if its just a breather hose, either way its probably sucking in s**t and contaminating your oil!

 

[jjones82]

Its definatly not the idle control valvel, thats behind the R on sport on the plenum and attaches to the elbow with the pipe you can see on the last pic. Mines was blocked off with a bit of plastic, I think the early phase 1's used it as a vacum line to the fuel rail for regulating the pressure i think?
Is your idle not high with that not blocked up?