[esievo]

hey guys, i have been thinking to decat my lsi coupe( D16z6 vtec engine)

is it worth it? i know i would not be able to pass MOT but this would not bother me.

will i feel the extra bhp with the decat???how much more bhp will i gain?

please give me some advice.

and where can i get a cheap decat pipe??

 

[Edd]

Its not going to make a massive different to be honest, you would be better off going for a complete system from the manifold back for power gains.

Take a look on ebay for a decat pipe they are fairly cheap

 

[stug45]

you could spend upwards of £600 on intake and exhaust and get no more than 10hp. or change engines for £600 without labour and get 50hp+

decatting alone could give you 5hp as it is the most restrictive part. if you already have a cat back system you will notice a large increase in noise, a tiny bit in engine response and get some hp back.

 

[crxhugh]

humm 5's a bit optomistic!

if you decat a standard exhaust you will notice one thing, your fuel being used quicker!! it wont do anything else really, with a full system like edd suggests you will see a better gain

 

[paul20v]

no leave it be its not worth the hassle very little gain you wont notice .

 

[paul20v]

humm 5's a bit optomistic!

if you decat a standard exhaust you will notice one thing, your fuel being used quicker!! it wont do anything else really, with a full system like edd suggests you will see a better gain

your fuel being used quicker thats a good one , i am intrigued as to where you got that little nugget of info from.

 

[crxhugh]

because the exhaust gasses can escape quicker, it often causes over scavvenging of the cylinders, leading to the fresh mixture leaving to soon, so you end up keeping the power on for longer, thus more fuel! also its similar to when you have a hole in your exhaust, you use more fuel, smae as a de-cat.

i'm not saying you tanks going to go from a 300mile tank to 250 but there is a small increase in consumption

 

[paul20v]

sorry mate your well off there exhaust gases escape quicker thats good, over scavenging of cylinders how can this happen when the cylinder with the fresh mixture in has its exhaust valve closed , all it does is clears the exhausted cylinders faster ie a fresher fuel to air ratio next time round and sligtly more power not that any exhaust is going to give you that much anyway , you use slightly more fuel because you drive it harder at the end of the day,exhausts only help slightly with high end revs as it does allow slightly more exhausted air to clear the cylinders for a fresher burn next time round.

 

[Lois]

Id decat it, ive got my esi decatted and it took of half a second from my 1/4mile time....not sure on bhp diferences but it def changed something! lol

d16z6 is an esi though... :-

Oh and my car passed MOT with the decat.

 

[paul20v]

high end revs a cat will make a slight difference but not loads ,turbo cars respond to a decat better than a n/a car as the more free gas flow spools the turbo up quicker so you lessen lag,
and also you dont need a cat for test , the car just has to fall into the specified limits for the emmisions
also your quarter mile was the decat done on the same day as your runs , otherwise you have to take into consideration track temps ,ambient temps , and lots of other factors also were your reaction times the same for the to different runs this may well have effected your half a second difference.

 

[Lois]

Not on the same day, but the time i ran it with the decat it was actually hotter! so would of thought that would of made it worse if anything lol.

 

[paul20v]

well it should effectively be slower on a hot day , but the track would have more traction
its all swings and roundabouts, like i said there will be a slight difference with a decat there has to be , unless you put in a hiflow sports cat then theres no difference ,this could go on indefinately im going to stop now TTFN

 

[Lois]

Lol its cool i no what ya mean