What is the benefit of decat? - LotusTalk

300RR · 02-08-2012, 08:21 AM

what is the benefit of decat the exige s240?
does the car get more hp, faster or just sound louder?
before decat,the car can feel the pull stronger and hit 220+km,after decat the car feel lighter, less pull but only do 200+km :-(....
should i just put back the catalytic....?????

shay2nak · 02-08-2012, 07:13 PM

+: more power, lower heat retention, lighter weight

-: louder, emissions

when you removed the cat, the A/F ratio was changed causing you to lose power (most likely). It's possible it became more rich, happened when I installed mine. You need to tune for it, otherwise put the cat back on.

Harix · 02-08-2012, 07:20 PM

It keeps your cat like new.

Elige · 02-08-2012, 11:31 PM

Fire balls!

t955152 · 02-08-2012, 11:35 PM

gun shots! love it.

zygotesoup · 02-09-2012, 04:40 AM

SwingLo · 02-09-2012, 05:17 AM

Its the same as dedog.

t955152 · 02-09-2012, 12:19 PM

i love this one

Quote:

Originally Posted by SwingLo

Its the same as dedog.

RCCola · 02-09-2012, 01:04 PM

Quote:

Originally Posted by shay2nak

+: more power, lower heat retention, lighter weight

-: louder, emissions

when you removed the cat, the A/F ratio was changed causing you to lose power (most likely). It's possible it became more rich, happened when I installed mine. You need to tune for it, otherwise put the cat back on.

+: louder

-: can smell sometimes

You won't blow out your cat packing with a decat

My tune also went rich

300RR · 05-09-2012, 05:44 PM

Quote:

Originally Posted by RCCola

+: louder

-: can smell sometimes

You won't blow out your cat packing with a decat

My tune also went rich

after one month i did the decat and now i put it back in.
it feel much more power and with better pull.
give higher top speed.....

EricH · 05-10-2012, 03:43 PM

My thought behind decat was that the cup cars have it. Back then the dyno results I saw were about 10+HP peak. True, low end might have been lower due to decat.

My car is tracked often so for me it is worth eliminating the heat and it is common for the cats to crack as well.

Exige-S stock exhaust decat dyno runs

GronkDaSlayer · 05-10-2012, 04:33 PM

decat also makes your car not street legal anymore (in CA at least)

addertooth · 05-10-2012, 07:52 PM

It makes it not street legal anywhere in the US, just some places don't check and don't care. Shay2nak was spot on in his assesment, I will add one caveat, all the things he says is true with the correct tune. With a bad tune, well, you may lose HP.

shay2nak · 05-10-2012, 10:08 PM

Quote:

Originally Posted by EricH

My thought behind decat was that the cup cars have it. Back then the dyno results I saw were about 10+HP peak. True, low end might have been lower due to decat.

My car is tracked often so for me it is worth eliminating the heat and it is common for the cats to crack as well.

Exige-S stock exhaust decat dyno runs

you gain about 10wtq downlow also.

haye · 05-11-2012, 12:25 AM

When you remove your cat do you always put it back on for the MOT test?

squidward · 05-11-2012, 01:30 AM

Yes if you want to pass. In California, a smog test pass is required after the first 5 years of a car's lifespan. It isn't comprehensive, so the car can be a piece of crap about to fall apart, with no hood or roof or doors, or even wheels for that matter and would still pass as long as its within established emissions standards (so long as you can get the car to the smog test shop).

2seatsonly · 05-15-2012, 10:35 AM

Quote:

Originally Posted by addertooth

It makes it not street legal anywhere in the US, just some places don't check and don't care.

Ditto. For those in the US, the US Clean Air Act was amended in 1990 to make it illegal for anyone to "remove, bypass, defeat, disconnect, damage or in any way render ineffective any emission control device or element of design that has been installed on any motor vehicle..." Individual owners are subject to a $2,500 fine, and any dealers or mechanics that do it for others are subject to a $25,000 fine. That amendment still stands, and there was a recent - within the last 2 or 3 years - crackdown on several auto tuning shops across the country that were doing that.

Of course, I live in Florida, where you could drive down the street in a home made smog machine and no one would bat an eyelid. But I would still be breaking the law if I disconnected any emission control piece that came with the car.

holmz · 05-15-2012, 06:11 PM

Quote:

Originally Posted by GronkDaSlayer

decat also makes your car not street legal anymore (in CA at least)

The fines can be pretty high.
Is the 2500 Fed added to state fines?

VisualEchos · 05-15-2012, 06:43 PM

The sound is absolutely fanmotastic!

haye · 10-31-2012, 03:05 AM

Oh ok, in London where I live, most just remove the cat after the MOT has passed :P which I now know is an equivalent of a smog test in the USA. Do all states over there require a smog test? I heard there are different rules between each state?

Car service

02-08-2012, 08:21 AM	#1 (permalink)
300RR Registered User Join Date: Feb 2012 Posts: 20	What is the benefit of decat? what is the benefit of decat the exige s240? does the car get more hp, faster or just sound louder? before decat,the car can feel the pull stronger and hit 220+km,after decat the car feel lighter, less pull but only do 200+km :-(.... should i just put back the catalytic....?????

02-08-2012, 07:13 PM	#2 (permalink)
shay2nak Noways iz sittin outsides Join Date: Dec 2003 Location: Calipornia Posts: 20,933	+: more power, lower heat retention, lighter weight -: louder, emissions when you removed the cat, the A/F ratio was changed causing you to lose power (most likely). It's possible it became more rich, happened when I installed mine. You need to tune for it, otherwise put the cat back on. __________________ save ~10 lbs gain 1 hp EQ: Y=(190*X) / (1984-X) where Y is (HP) and X is (lbs) '07 Lotus Exige S310 WTC 2

02-08-2012, 07:20 PM	#3 (permalink)
Harix Star Certified SMOG tech Join Date: Feb 2009 Location: San Gabriel Posts: 645	It keeps your cat like new. Last edited by Harix; 02-09-2012 at 12:51 PM.

02-08-2012, 11:31 PM	#4 (permalink)
Elige Addicted Join Date: Jul 2005 Location: El Ayy Posts: 1,483	Fire balls! __________________ 05 graphite grey elige with zero mods.

02-09-2012, 04:40 AM	#6 (permalink)
zygotesoup Registered User Join Date: Nov 2006 Location: Rochester, NY Posts: 2,658	__________________ 2005 Krypton Green Lotus Elise 1993 Black BMW 325i

02-08-2012, 11:35 PM	#5 (permalink)
t955152 Terry Join Date: Oct 2010 Location: Los Angeles, CA/ Cupertino, CA Posts: 1,303	gun shots! love it.

02-09-2012, 05:17 AM	#7 (permalink)
SwingLo All Hail King Joffrey! Join Date: Apr 2010 Location: Chicago-ish Posts: 6,321	Its the same as dedog. __________________ '08 Elise SC (Chrome Orange) - Stock...so far... '05 Elise (RIP) - sauteed, flambed, bar-b-qued, fried '69 Leyland Mini Moke - good times! '12 Jeep Wrangler Unlimited Sahara - daily fun The Wife's Car - who cares?

05-10-2012, 03:43 PM	#11 (permalink)
EricH Registered User Join Date: Nov 2007 Location: Dallas, Texas Posts: 1,000	My thought behind decat was that the cup cars have it. Back then the dyno results I saw were about 10+HP peak. True, low end might have been lower due to decat. My car is tracked often so for me it is worth eliminating the heat and it is common for the cats to crack as well. Exige-S stock exhaust decat dyno runs __________________ Click links to see my 2008 Lotus Exige-S 240 , '99 M3, 505rwhp '89 Mustang ( sold) , '05 WRX STI ( sold) homepages or here for my M3 vid (11MB)

05-10-2012, 04:33 PM	#12 (permalink)
GronkDaSlayer Registered User Join Date: Oct 2009 Posts: 360	decat also makes your car not street legal anymore (in CA at least)

05-10-2012, 07:52 PM	#13 (permalink)
addertooth Painful Novice Join Date: Nov 2011 Location: Arizona Posts: 2,054	It makes it not street legal anywhere in the US, just some places don't check and don't care. Shay2nak was spot on in his assesment, I will add one caveat, all the things he says is true with the correct tune. With a bad tune, well, you may lose HP. __________________ Storm titanium 2005 Elise with carbon fiber spoiler, BWR sway bar, BOE toe links, gPan2, LidBone, sector 111 wheel studs, Grey RAC Monolite wheels with toyo R1R, Team Dynamics 1.4 with Hoosier A6/R6s, Katana2 Supercharger, ECU with 265 flash. PPE headers w/decat, CEL angle eliminator, Silent touch catback, Rear Panel Eliminator, HKS intake, V2 fuel tank, Walbro255 fuel pump. HID lights.

05-11-2012, 12:25 AM	#15 (permalink)
haye Registered User Join Date: May 2012 Posts: 5	When you remove your cat do you always put it back on for the MOT test?

05-15-2012, 06:43 PM	#19 (permalink)
VisualEchos Photographer Join Date: Aug 2006 Location: Missouri Posts: 2,029 Images: 3	The sound is absolutely fanmotastic!

10-31-2012, 03:05 AM	#20 (permalink)
haye Registered User Join Date: May 2012 Posts: 5	Oh ok, in London where I live, most just remove the cat after the MOT has passed :P which I now know is an equivalent of a smog test in the USA. Do all states over there require a smog test? I heard there are different rules between each state? Car service

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