Ebay Cat + Exhaust

[SKITTLES]

Say I wanted to get...

http://cgi.ebay.com.au/Catco-High-Flow-Racing-Cat-Converter-S13-R32-R33-Z32-/180612132100?pt=AU_Car_Parts_Accessories&hash=item2a0d526d04#ht_1438wt_907

And

http://cgi.ebay.com.au/JDM-Performance-Catback-Exhaust-System-Skyline-R33-GTST-/150547490786?pt=AU_Car_Parts_Accessories&hash=item230d5467e2#ht_1242wt_907

Are they any good?

I'm assuming they will go together, but will they fit on my bog stock RB25DE?

Edit; I know it's a 3" and it'll loose compression, that's not of a concern. The concern is whether it'll fit or not.

Car proposed is an R33

Edited January 17, 2011 by SKITTLES

[Socrates]

backpressure not compression, btw

[mad082]

if it is a coupe then yes it will fit. also, yes it will be louder than a jet engine and yes it will lose power down low.

[PSI-FED]

Just undo the flange where the cat is and drop the exhaust off. Its:

- FREE

- ALOTTTT Louder

- Very lumpy and loud idle

- Easier and quicker to do as opposed to fit entire exhaust

- Easy to revert to stock

Your gona end up getting defected with either and on a NA car the performance you will get from the exhaust is negligble so i know which one i would pick

[SKITTLES]

Like I said, performance is not a concern. All work I'm thinking about doing is geared towards the end product which is turbo charged.

3" exhaust on a turbo charged engine isn't too bad

Sounding like a jet engine doesn't appeal to me... hm... I'll have a chat to a couple more performance shops.

Thanks for correcting me, Socrates. People have been telling me "compression" so that's just what I've been saying. Not too sure how back pressure helps N/As with performance but i'll do a bit of a google search

Have had a couple engine problems start to happen recently... gotta work out wtf. Visiting my mechanic to have a chat tomorrow.

Thanks for the replies guys

[Socrates]

To my understanding compression is in the cylinders and backpressure is exhaust flow pressure, that needs to be kept up with NA cars.

[mad082]

there is much information about back pressure on the internet, however most of it is incorrect (since they say that back pressure is good on a NA). the simply fact is that you don't want back pressure on any engine. however that doesn't mean you can put a 5" exhaust on and not lose power. with a NA engine you still need an exhaust size that maintains exhaust gas speed. unfortunately you can't have a variable sized exhaust to give you optimum flow at all RPM. you have to pick a size that is going to give you optimum flow at the RPM you are going to be using the most. on a stock car to be used everyday on the road and driven normally the stock size is ideal as it will give the best flow in the lower end of the rev range. a slightly bigger exhaust will move the power a bit further up the rev range, and then a big exhaust will give you more power up top, but at the expense of low down power. if the car is going to be used for race applications then you can get away with a big exhaust as you spend pretty much all your time at high rpm so losing some low end power is of no concern, however if you were to put a 3" exhaust on a skyline that was going to be used on the highway all the time you would find it a bit of a slug (as well as the noise driving you bonkers).

back pressure is just a side effect of having an exhaust that provides optimum flow in the lower rpm range. the back pressure doesn't actually occur until higher in the rev range.

[Socrates]

truth^