I’m unable to post this in my Member’s Machine thread, so I’m making a new thread about it here.

The final mod I did to my Verada was the manual conversion. After all the issues with the conversion and the boost leaks from the supercharger were fixed, the car was running tip top. It just needed a final retune. After the retune on a correctly reading dyno my car only made 164kw atw. This was at least 10kw atw less than I had expected. My tuner also agreed and mentioned that something was fishy about the exhaust. I remember him saying it felt like something was restricting the power. So I thought great, now I’m gonna have to fork out more money for a bigger exhaust (was running a 2.5” system, was then contemplating a 3” system).

I was prepared to keep modifying as I was hooked on the better power and drivability of the car but wanted more. It became like a drug addiction. This is where I think maturity and common sense kicked in as I started looking at the cost of getting more power (bigger exhaust, water injection and maybe even a rebuild of the engine to take on more boost). So i decided to sell the car and move onto something bigger and better.

During the sale of my car I sold off almost all the mods I had done over the last few years. One of these was my entire exhaust system which I sold to Lugo. Didn’t think it would be an issue as his car is NA so it wouldn’t be restrictive or cause any problems. Boy were we wrong!

After being on his car for a while it created its own issues. He took it to an exhaust shop where they found the high flow cat was not actually high flow. It was just a normal cat which had destroyed/collapsed on itself, because of the extra heat going through it due to extra power created by the supercharger. Once I found this out I spoke to my tuner and he agreed that the collapsed cat was robbing at least 10kw atw, if not more. So it looks like his hunch about an exhaust restriction was correct.

I won’t mention the name of the exhaust shop that sold me the wrong cat (and also botched up the extra resonator install), as I don’t want the Mods to close this thread. If you want to know who it was PM me so you too can keep away from this dodgy exhaust shop in Ringwood.

So, if I knew then what I know now about the cat would I have hung onto my Verada? Probably but not for too much longer as common sense would have still prevailed in the end lol
It was fun modding the Verada and making it into what it became but at the of the day it was prolly best I moved on when I did.

When the time comes for high flow cats for my current car i will go for Ballistic 100 cpi cats which have a proven track record on being one of the best cats out there. And this time i know they will be high flow cats coz the company that sells them is a forum advertiser on the LS1 forum and actually care about their reputation.

Was hoping there was a write-up on this, even though I saw the discovery in Lugo's machine thread

Sucks...

aren't 100 cpi cats illegal?

aren't 100 cpi cats illegal?
Yeh pretty sure they are

its always nice when you figure something out...

ahhh... yeah ive had so many drams like that with my car,

bought mine being told it had 550cc injectors from a reputable mitsubishi place over here in WA which members on here continue to use sadly.

Previous owner paid $200 a piece for them (supposedly genuine bosch). I had them bench tested, and flowed in at 432cc's and were chinese imitations, not genuine bosch (numbers scratched).

On the up side, glad you figured this out Mohit and all the best with the new wheels

Surprised not you, lugo, mal or the workshop picked up that it was just a standard cat.

;1076190']

Surprised not you, lugo, mal or the workshop picked up that it was just a standard cat.
From the outside it looks like a cat, like any cat. Only when it was cut out was the discovery made.

Riiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiight :doubt:


From the outside it looks like a cat, like any cat. Only when it was cut out was the discovery made.

I know it looks like a cat but there is a big difference in an OEM one and a magnaflow. :P but yeah who cares

Right. I have deleted the useless drivel in this thread. Lets keep it on the original topic please.

;1076201']

I know it looks like a cat but there is a big difference in an OEM one and a magnaflow. :P but yeah who cares
It was a 2.5" Magnaflow cat, just not a high flow version as i had been told (or lied to about).

Its a shame to hear about shonky workmanship anywhere but particularly because ive used them in the past and have had great work by them. Just goes to show that even with recommendation YMMV.

Its good of you to share the information with those of us that are either supercharged or looking into forced induction.

Its a shame to hear about shonky workmanship anywhere but particularly because ive used them in the past and have had great work by them. Just goes to show that even with recommendation YMMV.

Its good of you to share the information with those of us that are either supercharged or looking into forced induction.
Yeh i'm surprised the work they did on your car has been good. Once i had a knocking noise coming from the exhaust. They tried to tell me something needed replacing. Turned out all that was required was for a bit of exhaust pipe to be heated and moved to the side slightly. Another shop did this for me btw.

Nowadays i know a lot more about cats and cpi ratings due to doing more research. If only i had known this a couple of years ago and not gone only on people's recommendations of a particular shop, it could have turned out differently :)

Maybe anyone that is queerying wether an exhaust is to restrictive or you have a callapsed cat etc should get a backpressure test done,this would surely sort the wheat from the chaff cheaply if power is down?

Maybe anyone that is queerying wether an exhaust is to restrictive or you have a callapsed cat etc should get a backpressure test done,this would surely sort the wheat from the chaff cheaply if power is down?
My tuner said a similar thing when he had the hunch about the restrictive exhasut. Can't remember exactly what he said now as it was a few months ago, but something along the lines of drilling a hole in the exhaust and inserting something in there to check on the exhaust.

I have no trouble with you naming these clowns as I myslelf removed that exhaust and showed you where they had bashed in the line weld on your fuel tank so the exhause would clear it after they not only shortened it too far as it was actually a 3.0 version (shorter cat thus longer pipe between the cat and the first resinator) but they also did one of the worst joints I have seen. These clowns I believe in Ringwood do not deserve any business from this club point blank

As for the cat, to be honest, it was aftermarket, was not looking for anything other than to change it over, as it was all 1 peice from extractors right throuth to the join over the rear axle it would have had to be cut open to look as Mohit stated.

In short, this exhaust work was a disgrace and a shame as had heard good things about them. I took my XT there though to get a quote and the guy was having a full on arguement with me as I wanted a particular cat on the car as I am converting to EFI and want to make sure all is good, they were telling me I had to cut my floor even though there are slim line cats made these days for this exact purpose

The shop in question is Ringwood Performance Exhaust. I would stay away from them like a heterosexual man stays away from a transvestite.

Just to clarify the cat that was there wasn't anything special, it was a 2-2.25" (can't remember exactly now, pretty sure 2") standard generic cat, wasn't even a magnaflow. I personally didn't pickup on it because at the time I had no idea what the difference was cosmetically, obviously I do now.

What does surprise me is why no one who worked on the car picked up on it, not to single anyone out, but surely someone who knew cat's would have looked at it at some point and thought, hang on that's not right. Either way, it's been replaced now, and it did make a big difference.

Short of the cat being labelled as a high flow unit either identifiable by a stamp, sticker or looking very "blingy", it'd be impossible to determine a high flow from a standard flow unit.

Of course it was sold to Mohit on the understanding that it was indeed a highflow unit.

Just to clarify the cat that was there wasn't anything special, it was a 2-2.25" (can't remember exactly now, pretty sure 2") standard generic cat, wasn't even a magnaflow. I personally didn't pickup on it because at the time I had no idea what the difference was cosmetically, obviously I do now.

What does surprise me is why no one who worked on the car picked up on it, not to single anyone out, but surely someone who knew cat's would have looked at it at some point and thought, hang on that's not right. Either way, it's been replaced now, and it did make a big difference.
Thanks for clearing that up. If it wasn't really a Magnaflow cat then they've got some balls as it was sold in a genuine Magnaflow box :flame:

Short of the cat being labelled as a high flow unit either identifiable by a stamp, sticker or looking very "blingy", it'd be impossible to determine a high flow from a standard flow unit.

Of course it was sold to Mohit on the understanding that it was indeed a highflow unit.
Well the Magnaflow 2.5" hi-flow is quite a bit larger than the standard one that was on the car.

i had a 2.25" cat, perhaps 400cpi (according to an exhaust joint) on the KS.. whilst the rest of the pipe work was 2.5"... why that happened, no idea... the exhaust job was done by JET-BLK

Well the Magnaflow 2.5" hi-flow is quite a bit larger than the standard one that was on the car.

Without the two cats to compare side by side it'd be hard to differentiate a high flow from a standard flow unit sans labelling of any sort.

i had a 2.25" cat, perhaps 400cpi (according to an exhaust joint) on the KS.. whilst the rest of the pipe work was 2.5"... why that happened, no idea... the exhaust job was done by JET-BLK
Thats pretty much what my setup looked like. Really defeats the purpose of the rest of the exhaust with that kind of restriction.

Re: the cosmetic difference, the hi-flow was probably 50-60% bigger, looked the same, just bigger. That and the clearly smaller diameter inlet and outlet would give it away I reckon.

Lugo, "all the people who worked on the car" were for starters not informed of the cat that was meant to be on the car, ie magna flow or other. Secondly, without either a/ recently having fitted or seen one or 2/ being familiar with the exact cat that was to be installed on the car, only coincedence would tell what could be fitted

The other thing, there are several different Magnaflow models out there, all different shapes and sizes. When I did the swap, I saw an after market cat and thought nothing more of it, most others working on the car would have thought the same way

Your car wasn't much different too mine except it was manual and mine was 4sp auto

I made 150.0kw atw before I replaced the locked sprintex SMT6 to and unlocked one

After 1.5 hours on the dyno I only make 154.5kw atw at pro-tek performance (i've got the dyno sheet around somewhere if anyone wants to see). My exhaust wasn't an issue because I had a proper "race cat", no resonators, and 2.5" piping all the way to a redback high flow.

I would reach peak power at 5000rpm then stay there all the way to 6000rpm. His guess was i needed bigger injectors which i too contemplated upgrading, but like you said, common sense prevailed after forking out $900 on new ECU and tune which gave me a huge power increase of 4.5kw :doubt:

Anyway, I've only ever heard good things from that exhaust shop until seeing what crap exhaust work they did to your car.