Stupid question - heat exchanger

[sjmtlewy]

First I had an easy question, now i'm moving on to the stupid ones. Bear in mind that up until a few months ago, when I bought my T25, I knew nothing of mechanics; this changing, albeit slowly, so have patience..

What does my exhaust heat exchanger actually do? I know on Aircooled it provides heat to the interior, but mines a W/C engine and I thought the cab heating came from the heater radiator in the dash?

[jason k]

if its watercooled you have no heat exchangers.

[kevtherev]

I thought the cab heating came from the heater radiator in the dash?

well done you got that right

Only An Aircooled motor has them as Jason said

[CovKid]

Generally true by my early watercooled system has a small heat exchanger used as a preheater to air filter box. That said, thats all it does and not strictly essential. I believe later systems don't have one.

[sjmtlewy]

Generally true by my early watercooled system has a small heat exchanger used as a preheater to air filter box. That said, thats all it does and not strictly essential. I believe later systems don't have one.

Aha - that must be it. Looks like one of these: http://www.justkampers.com/shop/type_25 ... 12019.html" onclick="window.open(this.href);return false; Actually the name on there does give a hint.

Cheers guys

[kevtherev]

oh ...you meant an air intake pre heater.

[sjmtlewy]

Well obviously! anyone would know that...

[CovKid]

You have the early exhaust system then like me, which actually gives you an advantage. It means you can fit the 1.7 - 2.0 header pipe and bolt on a stainless bike silencer (fraction of the cost of stock VW silencer if bought S/H) and lasts forever. See bottom of this WIKI page: https://club8090.co.uk/wiki/Exhausts" onclick="window.open(this.href);return false;

Top pic is later exhaust system but my WIKI article at the bottom shows you how to fit a bike exhaust with a short video to go with it. Noisier? Depends what silencer you use but everyone reckons mine sounds like a Harley Davidson - - ironed out allthe flat spots I had too.

[sjmtlewy]

I've got a new stock silencer, which was fitted by the previous owner. The whole system looks in pretty good nick, except the "air intake preheater" which is a bit rusty, though useable. How long do they generally last? (kept on drive under cover, with heater inside)

[CovKid]

The pipe that runs through it (like most heat exchangers) will last a lot longer generally. Unless the ailing preheat makes for very difficult starting I really wouldn't worry too much. The autochoke is doing the real work any way.

[toomanytoys]

I have run both of my T25's without the "warm air feed" for 5 and 10 years.. Never had an issue with a well set up and working engine, even in silly cold temperatures.. as by the time its defrosted there is enough heat in the engine and intake system to not cause a problem.. BUT, if you have water geting into the fuel system (lots of reasons why this happens, should all be in the WIKI) then you may get problems.. (but then it will be running a bit rough in anycase..)