A few dumb questions

[siringo]

Thought I'd spend some time learning a few things today. If some one can help me out with some answers that'd be great.

In the pic below, what's the thing pointed at by #1 and what's inside it??

In the pic below, what's the thing pointed at by #2 and what do they do?

In the pic below (sorry it's sideways), that thing pointed at by #3 is called the catalyst in the workshop manual. Is that the same as the catalytic convertor??? or is the catalytic convertor that small thing in the exhaust???

Or is the catalyst, what is also called the dump pipe???

I'm trying to work out what & where the dump pipe is.

And regarding the turbo, the cold air flows from the turbo towards the front of the vehicle through the big runner hose, through the intercooler and into the air intake. From what I could see it looks like air is present in the inlet manifold constantly, does that sound right??

Thanks for any help.

 

[Old.Tony]

1) Dunno, often wondered myself. It's shown in the manual with NO indication as to what it is.

2) Is the top of your fuel injector.

From the exhaust manifold, your turbo bolts on to the end, and the outlet of the turbo connects to the dump pipe. The catalyst (CAT, catalytic converter) bolts below the dump pipe and is where you've pointed 3 at. The dump pipe is a 90degree pipe above this.

 

[siringo]

That thing I've pointed 2 at is an electrical connection, aren't the injectors screwed into the left hand side of the head, the things the 4 steel tubes run into????

Wouldn't that dump pipe get realy very bloody hot???? I'm wondering how you could replace that easily like lots of people seem to do. I haven't seen it, but wouldn't it be a cast piece like the exhaust manifold???

 

[Old.Tony]

The fuel has to enter the injector, but the injector has to have an electrical connection as well, and that's them.

Yeah the dump pipe does, but the turbo takes a fair bit of the energy away. The dump pipe should peak around 550C or so, I guess, given that the peak temp on the exhaust manifold should be 750C and the turbo can suck up to 250C out of it.

 

[JPMC]

No 1 is just a baffle to quiet down the intake noise.

No 2 is the top of your injector as Old Tony said, what your talking about is the fuel tubes and nozzles that feed the injectors.

The dump pipe can get hot (up to 700°C) depending on the tune.

 

[siringo]

So these guys that say they replace the dump pipe with a larger one to improve performance, what would that be made out of??? I'm guessing normal exhaust piping or even heavier guage pipe wouldn't be able to handle 500 - 700C

 

[Old.Tony]

Steel can handle 1700C+ before it melts (depending on carbon level). They often use cast iron - like the exhaust manifold - and that gets hotter.

Larger dump pipes would allow the exhaust to escape from the turbo more quickly, but the effective power gain in that is marginal when compared to other cost/gain items (eg chips).

 

[sparra04]

Dump pipe material was explained to me by beaudesert exhausts
They use steel because it disperses heat a lot quicker than cast iron
Cast can be heated to a lot higher temps BUT retains heat for a lot longer
I have steel dump on the nav and stainless on the skyline
They both made a huge differance to spool up time
And the performance gains are defiantly noticeable

 

[siringo]

Thanks guys, that's good help.