moconnor

iTrader: (14)

I will be starting a vacuum hose job soon and was wondering about the various hose sizes. I did a search and could not find an answer to my question.

Basically, there appears to be four sizes used in a hose job: 3.5mm, 4mm, 6mm, and 8mm. It is pretty easy to eyeball the existing hoses and tell the differerence between 3.5/4mm and 6mm hoses, but I am not sure how one tells the difference between 3.5mm and 4mm hoses. Is it mainly a matter of feel deciding between the two when installing?

Also some write ups mention 4-6mm adapters for certain lines but it not clear to me why or where these adapters are needed. There are no adapters that I can see on the stock lines.

Where are the 8mm lines? The only lines that size that I can see are the lines to the BOVs, which don't get much heat and don't really seem that they would need to be replaced.

DaleClark

iTrader: (55)

The 4mm line just doesn't fit as well as the 3.5mm - use the 3.5mm. You'll primarily need 3.5mm line, as that's most of the lines on the car. There's some 6mm and 8mm, but not as much.

There are a few stock lines that are molded and go from one size to another. In some cases, silicone is so stretchy that you can just use a small-size hose and be good to go.

Dale

DaveW

From the last page of the "Hose Job - Rubber" thread:

30Ft 3.5MM (old kit was 40Ft)
12Ft 4.0MM (old kit was 15Ft)
12Ft 6.0MM (old kit was 16Ft)
4Ft 8.0MM (kept this the same)

https://www.rx7club.com/showthread.p...&goto=lastpost

moconnor

iTrader: (14)

Makes sense - though I have Viton so I am not so sure that this applies. It seems very thick and reluctant to stretch.

Saw those numbers. I just could not see any details anywhere describing when 4mm was to be used and when 3.5mm was appropriate. That kit has quite a lot of 4mm hose - I mean 12' is probably 15-20 small lines.

And some write ups do not even mention 8mm hoses.