Is 3.5mm and 4mm Vac Hose basically interchangeable?

[Red Dragon]

About to hit purchase on about $100 worth of high temp silicone vac hose and IC couplers.

the 3.5mm hose is $1.25 a foot, while the 4mm hose is $1.00, so I was thinking of doing all the main vac line in the 4mm. Is this big enough to perhaps not stay on, or should I have nothing to worry about? I measured what I have on there now at 3mm

Thanks

 

[oldskool-nick]

When I redid my vaccuum hoses with silicone, I had some problems with them popping off. I put zip-ties on them and they still popped off. Pretty big PITA when you suddenly have a huge vac leak in the middle of the highway.

This time around I'm going with all new rubber vac lines ($0.58/ft!) and they stay on really well. I just redid all of them on my mr2 and you can tug on them pretty good and they're tight.

Unfortunatley I don't know what size silicone hose I used on the Supra but it was most likley larger than stock and I had bad experiences with it. I can check the size tommorrow if you'd like.

 

[Red Dragon]

wow, ok well i think that pretty much answers my question... thanks

 

[supra90turbo]

Yeah, go with 3.5mm. They just fit better.