Jonny Park

Hi folks.I am going to be putting a stainless decat downpipe on my standard v3 sti.
Is heat wrap essential or will it be okay without? Your thoughts on this please.

edsel

iTrader: (2)

Not essential. But seeing how close the pipe is to the bulk head and its a cheap way to keep some of the noise out of the car, its seems silly not too. Unless you like warm feet of course.

Worlasshasansti

Worth noting that wrapping stainless exhausts corrodes them like buggery.

Mick

Supercue

iTrader: (1)

Cheers Mick I had no idea

Jonny Park

Please excuse my ignorance but I was led to believe that stainless steel doesn't corrode?
So would an unwrapped down pipe be okay then? What danger could there be if any?
Also does anyone have any recommendations to what down pipe to go for? I have noticed that some have an open type 'mouth' where others have 2 holes.Am going to avoid the £100 ebay jobbies but don't want to fork out for high end RCM/Perrin stuff either.All advice greatly appreciated.

johnlogie

iTrader: (4)

I had an "open mouth" 3" down pipe on my classic and had no issues with it in the 6 years it was on(unknown brand, on the car when I got it). I had it wrapped and it was fine at 400bhp. My RCm manifold(headers) on the other hand cracked at the collector, not sure if this was down to wrapping or not but I've wrapped the new set.

Worlasshasansti

I had a custom exhaust downpipe on my mk2 golf 20vt conversion supplied by a local place who have a great reputation and are quite expensive and sought after (so you would think would have little reason to supply poor quality stainless) space was very limited in the mk2 so I wrapped it in fibreglass based heat wrap......I was then advised this accelerates corrosion so I removed it, after only 3 months the exhaust was pitted and starting to rust.

My brother wrapped his decat on his 964 (cheap ebay stainless) and that literally fell to bits after about 18 months.

The quality of the heat wrap may play a major factor in this?

Mick

Jonny Park

I have been looking at the difference types of wraps available & as with most things there are some very cheap stuff about that does actually look cheap is & crappy.dei stuff looks good & if you look about you can find it at a reasonable price.Does the corrosion issues come from the wrap constantly holding moisture again the metal?
I am probably not going bother with the wrap unless anybody can tell me a reason from a safety point of view?

Vxr2010

heat wrap has little effect on an exhaust rust wise , it has limited effect on performance too , my fsti has been wrapped for last 9 years or so and is on 150k miles with no ill effect , engine bay temp can be less , if you do wrap use a good quality wrap with lots of suppoting bits i.e. clips and metal pull clips , or it will break up and come off in bits , i have headers on the jdm sti wagon again engine temps are less , i put the wrap on then put a piece of metal over it and jubilee clipped that down , it kept on failing and loose bits of wrap coming off , there are other options out there for wrapping that work well

ossett2k2

iTrader: (9)

As well as keeping the heat from the engine bay and temps lower than without wrap it also keeps the heat in,hotter exhaust gases flow better so wrapping does have performance benefits imo
I've used cheaper wrap on my manifold,it does feel and look as good as DEI but was half the price,is doing its job well and the oem el manifold is holding up well(For now)

johnlogie

iTrader: (4)

I'm currently using the dei titanium heat wrap and I don't care what anyone says it deffo reduces under bonnet temps, fact!

ossett2k2

iTrader: (9)

So reducing temps and increasing flow,win win!
People don't just wrap to make it look pretty as you and others have proven.