for my 1999 classic.what diff would it make if a take them off

 

Two, one on the turbo down pipe and one in the center. If you remove the cat/s you will increase your torque and BHP.

Sam

 

dont do it without a remap or your asking for trouble!

 

why? surely just removing the 2nd cat but leaving the downpipe/cat isnt going to cause any damage without a remap?

 

You can remove both without a map, you may get overboosting so a map is a better way of getting safe power out of it, the standard ecu is pretty good, if you have a ppp fitted then I would say no, dont decat.

Tony

 

Surely getting a new exhaust system on a unmapped ecu/chipped car won't effect the running performance of the engine, it's just going to be a smooth exit is it not?

Maybe a remap if you just have a hi flow sports cat?

Sam

 

the standard map is set up with the standard restrictive exhaust, so yes if you make it more efficent the ecu map needs altering to compensate.

Depending on the car and the mods sometimes it just runs safe and you don't get the full potential out of the mods, and other times it runs unsafely and can damage the engine.

Simon

 

Thought my99 has a pre-cat in the uppipe meaning 3 cats

 

why? surely just removing the 2nd cat but leaving the downpipe/cat isnt going to cause any damage without a remap?

see what jgm just said yes the 2nd cat you can prob do without any issues but the car is mapped for a certain pressure when i had mine removed by a specialist i drove home off boost and it sat there till JGM came to map it

why try to mod or boost your car half ar*ed

 

Okay so remapping is a good idea as the standard map is set for different pressures, that makes sense.

What damage could it do not remapping it?

Thanks,
Sam

 

If you going to remap might want to think of other little mods to make a map worth while, fuel pumps £80, green pan filter £50, 3 port boost controller £80.
As said if you don't remap and remove the down pipe cat, then you have a good chance of over boostin. Over boostin will make you run lean(lack of fuel)

 

no the only cars with uppipe cat at 01~05 WRX bug and blob

 

thought the box in centre pipe is a resonator? it was on my 93wrx.

 

Wrx and sti had only downpipe cat, uk have a cat in centre as well

 

so would it be safe to remove the centre cat and fit a better backbox leaving the standard downpipe? or is a remap a must when removing the centre cat?

 

ave got a ss exhaust from cat back.it has some sort off remap.its boosting at 1.4 bar,its got a k&n panel filter to

 

Where is the up pipe located? I thought this was the same as the down pipe?

Thanks,
Sam

 

The clue is in the name. Exhaust gas goes up the up-pipe and down the downpipe. The up-pipe is between the exhaust manifold and the turbo.

 

Thanks,
Sam