De-cat and Torque Levels

[solarice]

Hi,

Just out of curiosity, have those of you with a decat noticed a drop in low end torque ?

been told this could happen to the micra, so thought id find out if anyone knew if this was true or not and if so is it a noticable amount.

Cheers.

Kris.

 

[Dr Zoidberg]

can't say that i have mate, then i haven't had the de-cat on very long

 

[Ian]

yeah mine has way more lower end torque then chies car

 

[chie]

ians has a cat and mine doesnt, mine seems to have more top end though (when it plays nice) im still playing with my piggyback fuel controller

 

[Davey C]

i 100% agree you loose a lot of low down grunt when you use a decat

my std k11 is nippy as a bar stuard bu then quickly runs out of puff once i get to higher rpm

the full exhaust system generally makes the car less drivable IMO. dont get me wrong its good but not as driveable ie you have to rev the car more to get the same out low down.

 

[solarice]

cheers for the replies.

hmm so with that verified, anyone know how id go about tuning the engine without loosing bottom end torque.

or is that a price you have to pay, until the engine up'd enough to compensate.

Kris,

 

[Dr Zoidberg]

so is it worth putting the cat back in then?

 

[Davey C]

you can get a 4-1 manifold instead of the 4-2-1, that will improve low end torque.

 

[Davey C]

so is it worth putting the cat back in then?

to that it very much depends how you drive, if you are a frequent one for hammering every gear every day ie redline 1-2-3-4 then no the benifits of the decat at higher revs are nice and make it worth while loosing a little low-end, but if you are a nippy driver that shifts quickly through the gears and doesn't really kill the car on a daily basis then it may be worth leaving the std cat in.
try it see what you prefere.

 

[Dr Zoidberg]

ahh right cheers dave, i do drive quickly but only 'hammer' it as you put every now and then.

what would be the best for making a car accelerate to 60 as quick as possible?

 

[Davey C]

0-60 is really about keeping the revs in the right range, so it wont really matter about bottom end if you are trying to get good 0-60 as you will be always in the 4-6200K rev band. you will always be above any rev area that will be affected by low end torque loss.

the main benifits behind the 4-1 manifold over the 4-2-1 are that the car becomes more drivable. it will be marginally slower (arguably) but will be better in general IMO.

so in answer to your question i would go for a 4-2-1 as they are far easier to get hold of and cheaper. with a decat-back exhaust system and a K&N panel filter (or shielded CAI setup). then follow that with a set of cams and dastek or emanage remap. this should see very healthy 0-60 times. alternatively sack it all off and go turbo or transplant!

 

[Dr Zoidberg]

ta dave helpful as always