Cats and Decats

[Guest Gaz-Szr]

Hi guys, sorry if this is in the wrong section (newb here)

 

Iv recently purchased my first supra, and one little thing is annoying me about not knowing much about them lol so i need to ask a quick question that will more than likely be answered pretty quickly.

 

I have no cats on my supra, im told that im supposed to have two of them. Now i know having no cat on turbo models is a good thing to have, but on the N/A models is it not right to have some back preasure forming ?

 

Reason i ask, is that my mate has the exact same car as me,same mods, (exhaust and apexi) but with just one cat removed and his out performs mine. There's little in it, untill we reach 4th gear and then he's slowly going past me. Also when i drop it into 5th it dosnt seem to want to pull anymore.

 

Any help will be appreciated

[ADL Mark]

You can have too much back pressure and two cats are a big restriction in the exhaust, so I doubt that's the problem.

 

Lots of things could influence the difference, mileage, condition of the engine, etc. Are they both the same gearbox too?

[Guest Gaz-Szr]

My engines done 62k and his has 90k on the clocks,mines the younger of them too, i think my engine runs pretty sweet sounds better than his actually lol his chugs a little and kicks out a bit of smoke under full throttle. So its just odd lol It could be down to weight and aero dynamics, i have a hooooooge spoiler where as he has the standard spoiler. I have a veilside body kit, where he has the C-west. I have 18's he has 17s. I guess it could all be a factor.

 

I also beleive that this might play a big part too: He's always been behind me and then over took me, so would i be generating a slip stream for him ?? Thats what im thinking anyway lol.

 

I maybe just daft, its just been niggling at me.