Intercooler Silicon Tube Collapse

[Patrini]

Hi,

Sry if the answer to this lies in a post somewhere, I have tried a few searches and could not find any info.

Just did a Front Mount Intercooler conversion on a 4AGZE and I notice that the Silicon bends used to join the alloy pipes tend to collapse quite dramatically under vacuum conditions i.e. idle etc.

Driving the car does not suggest any performance deficit or running problems, long term I suppose the hoses may wear out quicker.

So is this normal behaviour for Silicon bends (did not occur with the original hump hoses on the Top Mount)??? Or is it just the brand I am using ?? If so which brand is recommended are there some with extra reinforcing that prevent this occurring ??

Or should I get some mandrel bends and get the majority of the piping welded ??

Thks in advance for any advice.

Chrs, PAt

[oldcorollas]

are they cheap/thinwall ones? how long are they between metal pipes?

you could hoseclamp the outside (messy) or put expander spring inside to hold the shape?

[mullett]

It's a GZE thing. Because the throttle body is before the supercharger, the entire intake system is under vaccum when you're off the throttle, and they'll happily suck pretty much any silicon bend inside out. You can get bend coils for them, or use reinforced bends (as toyota did).

-RM

[Patrini]

Thks for the replies guys.

Hoses are 5 ply and I thought gd quality, lengths are minimised, except on the longer bends. May have to try combining mandrel bends and even shorter silicon tubes.

So is there a probem with them builging in/out i.e. performance or wear ??

Any idea where I can get the internal springs ?? google not helping much .

Chrs, PAt

[Casey-G]

Made my gze use a fuckload of oil.. I'll post up pics and some more info when I get home from work. Even though i had partially leaking valve stem seals it definitely accelerated oil consumption as once i replaced the bends with mandrel stainless ones oil consumption pretty much stopped dead in its tracks.

[LeeRoy]

Can you re-do the piping and have solid bends with silicon joiners only used on the straights?

[mullett]

Short silicon joiners (less than 2in free) will fix your problem nicely. It's not a problem with the quality, it's just that the hoses aren't rated for vaccuum. At full vac (if you ever got there) that's 14.7psi of pressure trying to crush the hose, it takes a fair bit of reinforcement to stop that. So yep, metal bends are your best bet.

-RM