X-over pipe diameter

[StarionChef]

so what happens when the car is idleing at the traffic lights, the only air in the pipe is vacume, and heat coming straight off the block and head is heating up the pipe like a spit roast? heatsoak perhaps?

I only write this as Ive done it on mine, with tape and without, and it does help. I also wrapped the rubber pipe from air box to turbo, and the whole air box, this also reduced lag, and allowed me to run higher boost.

Far out benny, far out Cookie :)

[Cookiemonster]

I would agree with wrapping the pipe from the airbox to the turbo.

But the air inside the pipe from the turbo will always be hotter than the air in the engine bay. I would want this heat to radiate out.

[StarionChef]

It would be good to have a cooling effect due to the heat radiating out, but I can't really see it happening.
My theory is to minimze temp increases on all air pipes. Blow air through a cold pipe and the temp stays the same, blow it through a pipe that is hot and the temp will go up.

Anyway, I love the stuf and put it everywhere :)

[Cookiemonster]

What ever floats ya boat. Thats what matters. ;)

[StarionChef]

hehe, well someones gotta keep coming up with crazy ideas :D

[Cookiemonster]

...like quad throttle body quad coil 4 cylinder engines. Hell, you should just run quad turbo's as well. :)

[Alspos]

4 Diahatsu Cappucino turbos would be the go. they're 600 cc engine. 1 turbo = 600cc, 4 turbos = 2400cc.... too easy with boost to spare.

[decoy]

ooooh do it chef!

[TD05]

oh man, I can't decide guys, Cookie says don't the Chef says do,

what about painting it BLACK, would that help also....

[ProZac]

wtf!? blow air through a cold pipe and it sure as hell comes out colder on the other side. How does and A/C work?

[Powerslave]

Maybe a better solution would be a heat-shield on the rocker cover , like for the brake booster ??? :beer

[StarionChef]

4 turbos? hehe, you think I havnt allready thought about that idea :)

I say wrap it up. If its a pipe that carries air to the combustion chamber, and you don't want the air inside to increase in temp, wrap it with reflective thermo tape.

The reason I crap on about thermo wrap is because it works, and works well.
First place I used it was on the standard exhaust manifold. I can't speak of any performance gains as I did it while installing the current motor, (after the dead DASH completly died) but one thing I did notice was how much cooler the enging bay was. Open the bonnet after a good hard run and you didnt get hit in the face by scorching heat, still warm, but alot cooler. I alos wrapped the dump pipe off the turbo down to the floor and noticed the floor wasnt as hot anymore
The next thing to be wrapped was the Xover pipe. This pipe was a 2in mandrell jobbie that came with the car from a previous owner(nxtime fame). I drove the car for a few weeks without the tape on it, so when I did wrap it, I noticed and improvement straight away. Lag was seriously reduced, and where the motor had previously detonated on hot days, it didnt anymore. ( so naturally I advanced the timing 1 deg to see where it would detonate again, then retarded it 1 deg )
After two succesful wrapping adventures, I bought some more and wrapped evey pipe I could.
unfortuanatly Ive since lost all pics of the motor in its early stage, so can't post any. I'm sure Ive sent some to plenty of folk on here so someone might still have one knocking about.

It might be overkill to wrap evrything, but who cares, its cheap, and works where it should :)

[Cookiemonster]

Thats exactly my point.. you've wrapped all those hot pipes and noticed the engine bay temperatures have decreased... so where has the heat gone? It's trapped in all those wrapped pipes.

I wouldn't wrap exhaust manifolds and dump pipes either.. they will run hotter and eventually crack a lot sooner.

Wrap only cold pipes (air box to turbo and intercooler to throttle body)

Well thats my theory and Im stickin to it. ;)

[Glynn]

i'm with cookie on this one.
you could argue that certain race cars wrap their exhausts, but the idea in their case is to mantain certain BMEP values and in any case they don't give a shit if they have to replace a cracked exhaust every two races or so... i do.
putting a heat sheild between the x-over pipe and the rocker cover makes sence. and in anycase majority of heat dispersal is radiant heat, not convectional. if you really want ot reduce pipe temps, use a water jacket.
i wouldn't... it would be a pain in the arse.

if you ever get the chance look in the engine bay of a f40 and notice what pipes are heat wrapped(or shielded) it seems Ferrari sides with cookie to

[StarionChef]

Very true,with ex manifolds/ pipes, they will crack faster (if its going to happen) and welds can open up. The idea is to trap the heat in the exhaust pipe, thus speeding up the air flow out of the motor, reducing lag ect, so in turn the metal is alot hotter than ever designed to be.
Sure, if you worrie about cracking a weld, or manifold, then don't use it. But as for me, I'm after every last Killowatt, so when something cracks, it cracks.
If I had to rely on an exhaust shop to make a new manifold or dump pipe, then I wouldnt wrap them either, but I don't, so I use it.

To be honest, I expected the manifold to crack not long after wrapping it, but its done about 10000ks so far so we will see when it eveuntually cracks. I'm rather keen to see where it cracks, as the earlier manifolds were prone to cracking anyhow. This one is off the dash motor so it could be a stronger casting, only time will tell. And lots of hard kays at the track :)