will gutting the cats cause problems with the engine managment

[madmax05]

hi all

Im looking into getting a second hand set of catalitic converters for the VE GTS and having them modified, I want to get them gutted and having a pipe installed through them so they look to the eye as genuine but in reality they are not..

I know this will get me in the shit if I get found out buy the boys in blue, and probably get me a defect notice...

but...

I want to know if doing this will cause problems with the engine management system via the censors in the exhaust?

cheers
MADMAX

[taztassio]

sorry, i think you mean this for racing purposes only/

and no, no problem with the engine management as far as im aware :)

[madmax05]

sorry, i think you mean this for racing purposes only/

and no, no problem with the engine management as far as im aware :)

yes, yes that is what I meant ;)

[Souljah]

A defect notice along with a $10,000 fine or some ludacris amount.
Why not get some decent aftermarket cats in the first place and be done with it?

[swingtan]

Souljah, you are correct.

removing the cats on a VE will send the ECM into 5 kinds of crazy as it tries to work out why the exhaust is not doing what it is meant to. If you are "really" going racing, you don't need to gut the cats, just remove them all together. Given the power figures quoted in many threads, cats are not the limiting factor.

Mind you, I guess you could gut the cats and then do the "washer mod" to really get that super GTS moving along...... :doh:

[ta22 ls1]

I personally think the negatives far outweigh the positives.
I have dyno tested a high flow cat vs no cat at all and achieved a 9kw increase (261kw vs 270kw). However, the risk of getting caught with a modified (gutted) cat and being handed a massive fine isnt worth 9kw in my books.
Get yourself a decent exhaust, OTR and MAfless tune and you'll be happy with your investment which wont be likely to cost you a big fine in the future.
Aside from that, I reckon when you take it in for a service, the workshop would be sure to have a few words....

[planetdavo]

Mind you, I guess you could gut the cats and then do the "washer mod" to really get that super GTS moving along...... :doh:

And let's not forget the "resistor mod" for the air flow meter too!

[rgmast]

And let's not forget the "resistor mod" for the air flow meter too!

And just get the angle grinder out and cut ya springs that should make it sit nice and low :jester:

[ta22 ls1]

And just get the angle grinder out and cut ya springs that should make it sit nice and low :jester:

all these mods sound fully sik :eeeeek:

[ratter]

Unless you get a tune to suit, gutting the cats or even replacing them with hi flow items will cause the engine light to come on due to the ECU thinking the cat is not working correctly

[macca33]

Why, unless you were mad, would you buy an $80k car, then do a hack job for a pissy gain, that if detected, will cost you much more than putting the best exhaust system money can buy on your car and keeping it all above board. I am perplexed...

[Highway]

Few years back i bought a VN 5 ltre ( Ex Cop car ) and a mechanic I got it from had made up some bolt in pipe sections to replace the cats.

Tried it a couple of times on the track with the pipe and it did not really make any noticeable difference that could be felt.

Just get some high flows ( 100 cpi ) and be done with it.

There is not really a great difference between the stock and high flows cats unless you are chasing every last kw.

Mike

[duke5700]

Why, unless you were mad, would you buy an $80k car, then do a hack job for a pissy gain, that if detected, will cost you much more than putting the best exhaust system money can buy on your car and keeping it all above board. I am perplexed...

What he said...

However each to their own, you will need the rear o2 sensor turned off otherwise it will throw plenty of trouble codes.

[Wonky]

Just buy some of Sureflo's Ballistic 100cpsi racing cats - very good price at the moment on group buy and flow very well. You're crazy to talk about piping the cats on a brand new expensive car with the (admittedly small) risk of a $10,000 fine! :eek:

[madmax05]

whats group buy?

[Wonky]

In Sureflo's sponsor's section - http://www.ls1.com.au/forum/showthread.php?t=128604

[Blown 540]

Why, unless you were mad, would you buy an $80k car, then do a hack job for a pissy gain, that if detected, will cost you much more than putting the best exhaust system money can buy on your car and keeping it all above board. I am perplexed...

+1 , not very often i am lost for words ,but this is one of them , beats me.

[Ferb]

I ran my ute with some cat bypass pipes. Just loads of extra noise and nothing else, now saving for some decent cats then tune. I now live back in Guernsey where we dont have any emision rules, but I need them fitted for MSA motor sport events.
I lived in Perth where the pipes were made but never fitted.

[NODDY347]

Dont the cats filter out dangerous gases that Unleaded fuel produces? Cant be great for the health side of things.

[Louie_D]

lol your crazy to even mention something like that on here, you do realise there are cops that use this forumn

[Wastegate]

Dont the cats filter out dangerous gases that Unleaded fuel produces? Cant be great for the health side of things.

What about the thousands of cars built pre-86 that don't run cats but are now forced to run unleaded because leaded isn't available! Was there a law making them all retro fit cats because of the dangrous gases they would be emitting now....?

Plus I'm sure all those VLs, VNs, and EA falcons on the roads have functioning cat converters after 20+ years :lol: