just wanna know is it ok to get rid of cat on non turbo import

Simple ANSWER = YES

 

but depends on what condition your turbos are in.

 

its a good mod.

warren, he has a non turbo :D

 

stacks of debate on this try a search.

Why would you want to remove them on an N/A?

was always told from the start on all cars you lose some power with a cat plus i have a nice twin 4"ss system on it and maybe it will sound better

It certainly will sound nice with the cats out, not sure how the reduction in back pressure will effect your n/a though.

TT Cat's out

Pro - no back pressure = quicker turbo spool up and response time

Nicer sound from the exhaust

Con - May decrease the lifespan of the rear turbo seals

 

NA Cat's out

Pro - deeper sound from the exhaust

Con - no back pressure = decrease in performance

 

on an NA in IMO not worth it.

take the spare wheel and jack etc out of the car and run with an aerosol tyre repair can instead - car lighter, car goes quicker - so I'm told (Nelson). Also remove the carpet from the boot - and the wood stuff - car sounds louder - I imagine.

 

Cheaper than removing the cats and with a performance gain...

 

cheerz

 

Jack

Originally posted by martinfa

warren, he has a non turbo :D

 

stacks of debate on this try a search.

DUOH LMFAO :D:D

then its not worth doing.

Originally posted by Jack

take the spare wheel and jack etc out of the car and run with an aerosol tyre repair can instead - car lighter, car goes quicker - so I'm told (Nelson). Also remove the carpet from the boot - and the wood stuff - car sounds louder - I imagine.

 

Cheaper than removing the cats and with a performance gain...

 

cheerz

 

Jack

 

 

I had all the boot and rear seats stipped out once so I took it for a drive to see what it was like. It was annoyingly loud and it wasnt nice exhaust sound I could hear. Loads of road noise too.

 

For a TT, it was too light at the rear. Pulling off from traffic lights caused wheel spin. Flooring it was nearly impossible as it would just create instant wheel spin in 1st and 2nd gear.

 

Stuart

I've run without a spare wheel and jack for 3 years now (in my NA). I do about 15 to 18k miles a year. Had 3 punctures but managed to get to a repairer before having to use the areosol - and got all three fixed. I also need a deeper boot so I don't carry the wood stuff either. I ground out the metal stands and bolted the straps to the 10mm hols that they left - still works although the carpet dosen't quite fit. I've also layed a layer of extra soundproofing to compensate for the removal.

All works fine... tempting providence...

 

cheerz

 

Jack

Originally posted by Jack

I've run without a spare wheel and jack for 3 years now (in my NA). I do about 15 to 18k miles a year. Had 3 punctures but managed to get to a repairer before having to use the areosol - and got all three fixed.

 

Jack

 

 

I think you where lucky. I have a tyre pressure reader in my tyres which tells me the pressure of all the tyres in real time. I got a pucture on the way back from Manchester and the unit detected a 3PSI drop and warned me. 1 min later it was down 4PSI. Another minute later it was down 6PSI and by the time I found a petrol station to try and pump it up, it was down 10PSI and I just decided to put the spare on.

 

Stuart

...it's interesting running without a spare. It makes you really listen to the tyres. As soon as I have a stone stuck in the tread I know about it, and I've detected the punctures in this way - you can hear whatevers stuck in the tyre as it repeatedly hits the road. I've been luck that it's always been the tread and not the sidewalls.

 

...but I do chicken out - I carried a spare on a trip to the south of France last year - didn't need it.

Originally posted by smw1

Con - no back pressure = decrease in performance

 

on an NA in IMO not worth it.

 

 

BACK PRESSURE IS BAD EVEN ON A N/A!!

 

:D

So you saying get rid of the cat's even on an NA ?

Looking through loads of posts on tt.net apparently less torque at low revs but slightly more at high revs. Good for racing where u keep the revs up, crap for any normal driving. Not particually recommended. Actual bhp should be slightly higher, like +2hp.

Originally posted by Paul C

 

BACK PRESSURE IS BAD EVEN ON A N/A!!

 

:D

I 100% disagree.

An NA engine works best with more backpressure.

If you put a 3 inch exhaust on an NA i bet you your car it will loose power.

if a loss of back pressure is bad, then why do NA rally cars and the like have larger bore exhausts????

Also i remember many moons ago when max power actually used to do decent write ups withou a pair of t1ts on the page, they once went to .. i think it was magnex.. where it was explained that u can actually go too big on an exhaust system.

They reckoned that as the exhause pulse out from the cylinder shoots down the exhaust when it hits a particular point in the exhaust an "echo" is reflected back up the exhaust towards the engine, as this echo returns off the engine to go back down the exhaust it creates a mini vacuum across the exhaust outlet helping the exhaust fumes in the engine to be sucked out and thus pass down the exhaust.

Interesting theory... but it was explaind that less back pressure was good, but you can go too big, ie no extra benefit

Originally posted by 300z

I 100% disagree.

An NA engine works best with more backpressure.

 

absolute bollox im afraid!!

 

backpressure is your enemy, its stopping exhaust gasses from flowing freely out of the combustion chamber.

 

scoops has basically hit the nail on the head. shockwave tuning is what counts, as the gasses exit the combustion chamber, the inertia of the gasses help pull the gasses of the next cylinder on the exhaust stroke. THIS PRINCIPLE REQUIRES LOW BACK PRESSURE!!!

 

I have yet heard anyone who says back pressure is good or required to explain WHY!!

 

incorrect FLOW through the exhaust may cause loss of power. but this is nothing to do with back pressure.

 

even on an NA engine, an decent free flowing exhaust will give a power increase.

 

I remember many years ago when the back pressure debate was going on, a very well respected engine tuner called David Vizard sayed "anyone who says back pressure is good is either lying to sell their product or doesnt know what they are talking about"

well i've heard it all now yes/no answers no one sure realy unless someone done it and let me know.

anyway my car runnin great at moment so best left alone.

f**kin backpressure who needs it . never had a car with a cat on in me life who needs em.

Originally posted by Paul C

 

BACK PRESSURE IS BAD EVEN ON A N/A!!

 

:D

 

Once again I find myself agreeing with Paul.

 

I actually have an NA, which has been decatted, and it runs better.

 

KMH: fill your boots, you wont regret it. You may need to look at your fuel mix,as the free flowing air (especially with a bigger exhaust) may cause you to run a tad lean. At low revs (minimum throttle opening) this may cause the car to hunt a little which is why a lot of people say that if you remove the cat the car loses power.

 

If evidence is needed look at performance exhausts for bikes, first thing they do is remove all baffles and give a straight through pipe. I know that somweone will raise the specter of exhaust valves which is about effectively changing the lenght of the pipe rather than the amount of air through it

Originally posted by jock

Once again I find myself agreeing with Paul.

 

I actually have an NA, which has been decatted, and it runs better.

 

did everyone get that :D ;)

Originally posted by Paul C

did everyone get that :D ;)

 

Bully !!! :D

 

What do you know anyway ;) :D, anyone would think you run a merc garage or something ! :D :D. What's that skip.... he does ????:p

I've just had a new SS system fitted and CATS removed (one had gone so no choice). At first, the boxes put in place of the CATS did not silence the car enough, sounded great but too loud. They then fitted 2 further boxes (see pic) and oh boy. The sound was just right, a little noisier than original but just enough rumble there. I have also noticed a power increase and torgue, takes off much better now. Some fuel economy improvement too.

 

home.btconnect.com/REGAL-VEHICLE-RE/P6160031.jpg

 

More pics here PICS

Forgot to mention though you'll notice from pics its an NA SWB