Catless DP coming from the US

[MZSPD6]

About 2 weeks ago I bought a Catless DP from the states, it will arrive Wednesday next week and I'm starting to get a bit nervous lol

I did my research on 247mazda.com and the DP got a really good review from the local US guys. I'm starting to think my MPS will be extremely loud and angry.....

I have already installed a custom cat-back and CPe CAI. About a month ago I had the EcuTek tune done at S&J Automotive and came up with an impressive 173kw's.
S&J will be installing the DP and retuning it on the dyno in the next few weeks.

I am most worried about turbo smoking issues, is there something I should do to stop this from happening?

What gain in kWh's/torque would you expect from the DP being installed?

Is my MPS going to be that loud that it will drone like hell and also get the attention of the police? (Cat-back now has no drone and sounds sweet!)

Any info would be much appreciated and I will also keep everybody updated on progress!

Thanks, Mark

[AD07]

Probably will be illegal, for both emmisions & noise. Catless = track use only.

[Yeldarb]

You can always add a 200 cell cat to aid in emissions issues like I'm doing in a couple of weeks. Won't affect performance. I'm doing it to stop the CEL coming on which it's been doing since installing the BM DP.



As for noise, it shouldn't cause too much of a change. It made my car sound better in fact. Now I have a 3" Open custom system I think it sounds awesome with the DP.

You should be fine in my opinion.

[Nuliaj]

Unless you're pushing for absolutely maximum hp (in which case you'd want a screamer pipe) there's little gains between a catless and a catted dp. There's really no good reason to run catless for a street car. US forums will say otherwise but depending on the state, they don't have as stringent emission laws as us, and they're incosiderate SOBs. Smoking will be more obvious without a cat, not to mention the smell. That's the next worst thing, driving behind people running catless.

Yeldarb I don't think that is going to fix your CEL issue. If you look at the picture below you can see there are two O2 sensors. In the stock system the two O2 sensors will give differnt readings due to cat number 1. What triggers the CEL in a catless DP is that the ECU compares the readings from the first and second O2 sensors and if they're too similar (which they will be now there isn't a cat to initiate the chemical changes) it will throw an CEL to do with CAT efficiency IIRC. From what I can see of your picture, you're adding a cat at the second cat position which has no sensor after it. You'll need to move the O2 sensor back after the cat in order to get rid of the CEL, but that will mean you'll need to to make further modifications.

[KRNAGE]

i found adding my DP made my MPS quieter or maybe a different tone so I guess it depends, thats with adding a manifold. but i guess it all depends

you may want to get a re-tune after installing the DP

[MZSPD6]

i found adding my DP made my MPS quieter or maybe a different tone so I guess it depends, thats with adding a manifold. but i guess it all depends

you may want to get a re-tune after installing the DP

Yeah I will be getting it retuned at the same time the DP goes in, I am going to buy a hiflow cat and cut/weld it in to the DP.
Sould be good, really looking forward to it

So no info regarding stopping turbo smoking before I innstall the DP, I have read an oil reducer will do the trick???

[KRNAGE]

i haven't had to use anything, its the luck of the draw weather you smoke or not, but i haven't had an issue

[RedDjinn]

what boost are you running? if its standard or lower u may be ok..

[MZSPD6]

Before the tune I was 14psi and after sat at 16psi, I don't want to push the car to the edge as it is my daily.

[Yeldarb]

Unless you're pushing for absolutely maximum hp (in which case you'd want a screamer pipe) there's little gains between a catless and a catted dp. There's really no good reason to run catless for a street car. US forums will say otherwise but depending on the state, they don't have as stringent emission laws as us, and they're incosiderate SOBs. Smoking will be more obvious without a cat, not to mention the smell. That's the next worst thing, driving behind people running catless.

Yeldarb I don't think that is going to fix your CEL issue. If you look at the picture below you can see there are two O2 sensors. In the stock system the two O2 sensors will give differnt readings due to cat number 1. What triggers the CEL in a catless DP is that the ECU compares the readings from the first and second O2 sensors and if they're too similar (which they will be now there isn't a cat to initiate the chemical changes) it will throw an CEL to do with CAT efficiency IIRC. From what I can see of your picture, you're adding a cat at the second cat position which has no sensor after it. You'll need to move the O2 sensor back after the cat in order to get rid of the CEL, but that will mean you'll need to to make further modifications.

Good advice, Troy is experimenting with moving the second O2 sensor after the CAT. It has helped with less CEL's, but I think I just need a better performing CAT. Another Brisbane member with a Gen II installed a 200 cell Cat with good results. I.e. No CEL's.

[MZSPD6]

DP arrived today

I am pretty happy with the fabrication, there is an egde that I will have tig welded and smoothed out on the inside of the V-Band area.

I have enquired about a Hiflow cat today and I will be going with a 200 cell cat. Not really worried about the DP firing CEL's as the tuner can stop them from coming up

Is it worth getting a Wide band A/F gauge? Being tuned I should not need one hey?

[MZSPD6]

Well 3 months later (no rush lol) the 6 is going tomorrow to the boys at S&J to install the DP

As the DP came from the states with no CAT they will be welding one in and also installing an aftermarket rear engine mount and re tuning the ECUTEK

I am a little nervous as some people have found the DP causes turbo smoking but I'm crossing my fingers that I wont meet that fate.

I have no idea how different the car will feel after but you all seem to say this mod makes a big difference so I will be eager to find out. Not that dyno readings are everything but hopefully I will be in the 190's (CAI,DP,CATBACK,ECUTEK) Edit- BULGEDECALS lol

I will post results up tomorrow night!

[toine888]

nice one mate, look forward to hearing the results!
i really want to put on a DP but didnt realise how expensive they were

[2XS]

The catless or catted DP won't cause turbo failure. It's the turbo failure that causes it.

The DP just shows it up easier because you have removed the 2 restrictive cats and replaced them with 1 less restrictive item.

[Bakis]

Everybody on here would know when these cars are cold the exhaust sounds very very loud. Can someone tell me what causes this? I have second cat deleted and muffler delete and when its cold its LOUD. Would getting a DP and having a 100/200cell cat make it louder?

[RedDjinn]

Everybody on here would know when these cars are cold the exhaust sounds very very loud. Can someone tell me what causes this? I have second cat deleted and muffler delete and when its cold its LOUD. Would getting a DP and having a 100/200cell cat make it louder?

yes for sure!! DP made a huge differnce in DB.. Think cuz when its cold it is reving 1500-2000rpm, hence its louder..

[Bakis]

Thanks luke, yeah if im not happy with how it sounds after the dp goes in i'll put the muffler back on then maybe save for a custom exhaust i really am thinking of a single outs on both sides same size as stock but tamper edges. But that's expensive im really hoping the dp doesn't make it that much louder on turn on. Higher revs and running rich would be the cause for the loud noise i think... Once its warm its awesome

[2XS]

On cold start, it opens a valve to get to emissions quicker. It is actually ewcirculating exhaust gas into the intake and the noise you hear is the intake sucking through the exhaust.
I'll get a picture of where the valve draws air from and goes later tonight.

A 200 cell cat will take out maybe 1 Db than a 100 cell cat.

[Yeldarb]

In my experience, the stock CBE did a good job of keeping the noise in check after the DP went in. On warm up, yes it was a little louder, but a nice volume as you could hear more of that potential being released with the cat delete. But once my full system went on, I was a little uncomfortable letting the car warm up in the driveway. Definitely louder. But once it cooled down, it sounded nice and deep, a bit like a boxer engine.

[Yeldarb]

On cold start, it opens a valve to get to emissions quicker. It is actually ewcirculating exhaust gas into the intake and the noise you hear is the intake sucking through the exhaust.
I'll get a picture of where the valve draws air from and goes later tonight.

A 200 cell cat will take out maybe 1 Db than a 100 cell cat.

...I agree. I went from a 100 cell to 200 cell. It brought the note of the car down a little.