Dyno for PPE down pipes

[AJP turbo]

I would always suggest catted downpipes over non-catted.


You're losing only 1-2hp by going performance catted over non-catted downpipes also, this was tested on a dyno, so the difference is negligible.

Wonder why so many people go catless then? From Honda's to Ford's and in between...I also think depending on the motor catted and non catted can have more desparity. I'd say the main benefit of being Catless is that all the over temp shutdowns and safety measures that are meant to save the cats life can be disabled giving you the ability to run harder longer...There are some compensations in the tune tables to reduce power  when the cat temps get hot...Sometimes it can be subtle power reductions that you may not even feel.

[BiGMaC]

I would always suggest catted downpipes over non-catted.


You're losing only 1-2hp by going performance catted over non-catted downpipes also, this was tested on a dyno, so the difference is negligible.

Wonder why so many people go catless then? From Honda's to Ford's and in between...I also think depending on the motor catted and non catted can have more desparity. I'd say the main benefit of being Catless is that all the over temp shutdowns and safety measures that are meant to save the cats life can be disabled giving you the ability to run harder longer...There are some compensations in the tune tables to reduce power  when the cat temps get hot...Sometimes it can be subtle power reductions that you may not even feel.

Very true ajp, but makes me contemplate.. since I'm not running a road race circuit..If I can't tell the power adjustment... did it happen.  Kinda like that tree falling in the woods when no one is there. I think many folks are still remembering the big carburated V8 days of straight pipes etc.  However, the only real argument I can currently fully understand is the cost the cats add to the DPs... There are of course differences in the exhaust note too.  I live in an emissions state, so given the data from development of the PPE DPs, it was very easy to go catted... different strokes...

[Livernois Motorsports]

I would always suggest catted downpipes over non-catted.

The smell is due to removing the catalytic converters since their function is to regulate emissions. With your emissions system now down two filters (catalytic converters) you are now exposing more emissions which equates to a smell, plain and simple. The noticeability of the smell depends on the design of the downpipes, gas, remaining emissions systems and other factors though I guarantee you any non-catted downpipes will produce a smell to an extent.

You're losing only 1-2hp by going performance catted over non-catted downpipes also, this was tested on a dyno, so the difference is negligible.

That is exactly why we recommend our race catted downpipes. The worst thing to me is whenever you pull your sweet looking  $40-50k sleeper that smells like raw fuel up to a nice valet, or you take the boss out for date night and she smells like raw fuel. The difference in performance like MD said is next to nothing. If your butt dyno is that sensitive you should work for dynojet lol. I run catted DP's on my ride, because I like not being in the dog house lol.

[AJP turbo]

 I prefer my Catless down pipes and I'm enjoying my emissions compliance and I live in an emissions state.....You won't really notice a smell if you leave your 3rd cat on...Unless you put your nose to the tail pipe while the car is waming up. I like the sound of my catless pipes with the stock cat back

[Livernois Motorsports]

BiGMaC, I agree with you. At some point we need to realize that 99.99% of these EB cars ARE DD's they aren't race cars nor are they giant displacement V8's. If we were talking about a race application, no cats...other than that the 95% street to 5% strip car cats are almost a must.

[Livernois Motorsports]

I prefer my Catless down pipes and I'm enjoying my emissions compliance and I live in an emissions state.....You won't really notice a smell if you leave your 3rd cat on...Unless you put your nose to the tail pipe while the car is waming up. I like the sound of my catless pipes with the stock cat back

And that's cool, nobody is arguing a preference. The point raised was, smell and performance. I had an 04 Mustang GT that had a full catless Basani system on it...so it is not like I am an advocate for the EPA lol.

[BiGMaC]

I prefer my Catless down pipes and I'm enjoying my emissions compliance and I live in an emissions state.....You won't really notice a smell if you leave your 3rd cat on...Unless you put your nose to the tail pipe while the car is waming up. I like the sound of my catless pipes with the stock cat back

The third cat in place is definitely the key to minimizing any odor.  I too have left the factory catback in place... I love the 4" Corsa tips... and may try their catback if they bring back the black ones, LOL...

[vernonator]

I prefer my Catless down pipes and I'm enjoying my emissions compliance and I live in an emissions state.....You won't really notice a smell if you leave your 3rd cat on...Unless you put your nose to the tail pipe while the car is waming up. I like the sound of my catless pipes with the stock cat back

Agreed - I have catless DP's and stock exhaust and there is absolutely NO smell what so ever - cost was a factor, did not want to pay for the cats and my state does NOT emission test so why spend the cash?

[peppelepugh]

I prefer my Catless down pipes and I'm enjoying my emissions compliance and I live in an emissions state.....You won't really notice a smell if you leave your 3rd cat on...Unless you put your nose to the tail pipe while the car is waming up. I like the sound of my catless pipes with the stock cat back

Agreed - I have catless DP's and stock exhaust and there is absolutely NO smell what so ever - cost was a factor, did not want to pay for the cats and my state does NOT emission test so why spend the cash?

^^^^ I'm in the same boat, well i don't have my DPs yet, but that was my opinion!^^^^

[MDesign Performance]

Wonder why so many people go catless then? From Honda's to Ford's and in between...

Cost.

Catalytic converters are not cheap, performance high-flow catalytic converters being even more expensive. Fact is people want more for their money and that is what they get by getting hatless downpipes, though they're also expelling more emissions. I bet if there was no price difference that would be a big factor of whether people choose catted or non-catted downpipes.

[ZSHO]

I just simply wanted to say with EPA laws and emmission compliances always changing and unfortunetly sometimes for the worse in some states,you never know how emmission friendly your state can become and dont know what the future will bring us tommorrow,so for a peace of mind i would also advocate for the catted DP version as MD stated above.Z,.

[FoMoCoSHO]

BigMac, on page one you said it was revving to 6800-7000K RPM?

How is that possible?

I ask because I'm messing around with shift point data and trying to figure out what max engine speed is.

[BiGMaC]

BigMac, on page one you said it was revving to 6800-7000K RPM?

How is that possible?

I ask because I'm messing around with shift point data and trying to figure out what max engine speed is.

If you look at the dyno curves on page 1 of the thread you see the pull through to 6800rpm... Dunno how, just reading the graph. Tune was stock then. I don't know what gear the car was in when the ECU/PCM began limiting as the up and down oscillations indicate. Don't know if that's any help. Your search may involve tune revisions and testing to find the sweet spot for any individual car.

[Vortech347]

I thought the factory rev limit was something like 6200

[AJP turbo]

I think the pickup wires for ground and coil pack for rpms were out of sync and or bad connection.the indicated revs from the dyno graph are not directly from the ecu they are grabbed from wire signals from the engine bay

And i think stock has a rev limiter of 6400 in gear but the commanded shift points by gear are in the low 6000's and high 5000's for 1st gear