[JRocker3]

Anyone have any recommendations based upon experience?

I'm thinking:

Evolution Racewerks catless DP and AWE exhaust (I'm running MPPSK now, and want to ditch the valves)

Bootmod Stage 2

Seems like the most straightforward route... but I'd love to know some feedback!! Thanks!

[Ahanix]

Initially I was going to say that this is going to be way too raspy, but since you already have the MPPSK you might be okay.

I'd almost say to try the catless downpipe and see where that takes you. I've heard from a lot of people that going catless dp + MPPSK makes the car too loud.

If that ends up being a different direction than you want to take it in, I think this sounds like a great idea... also, while you're at it, you should sell me your MPPSK exhaust...

[msk340i]

If you want to sell the MPPSK I'd take it. Please let me know.

[JRocker3]

Thanks for input... yeah the noise would be something I'm sure. Perhaps a catted option?

More-so concerned about feedback on the tunes out there. I could keep MPPSK exhaust and run a catted downpipe with a Stage 2 tune I suppose.

Anyone out there trying this?

[disintegrator66]

Originally Posted by JRocker3

Anyone have any recommendations based upon experience?

I'm thinking:

Evolution Racewerks catless DP and AWE exhaust (I'm running MPPSK now, and want to ditch the valves)

Bootmod Stage 2

Seems like the most straightforward route... but I'd love to know some feedback!! Thanks!

Damn.... I love the valves..... stealth when needed.... loud symphony when not needed.... YMMV....

[Wires]

Originally Posted by JRocker3

Thanks for input... yeah the noise would be something I'm sure. Perhaps a catted option?

More-so concerned about feedback on the tunes out there. I could keep MPPSK exhaust and run a catted downpipe with a Stage 2 tune I suppose.

Anyone out there trying this?

I'm running a similar setup with Active Autowerke catback exhaust. I ended up welding the exhaust flap back into the left tip to reduce the light throttle noise, You would get insane exhaust vibrations through the seat/dash under low RPM, higher load situations.

I had the VSRF catted DP first (5" cats) and then went to the ER 4" catted version. It has a really nice raspy note with the AA exhaust.

[neonnblack]

running a cts catless dp. resonator deletes into the mpe muffler. sounds great. i also have an electric cutout in it to really make some noise.

also running mhd stg2.

[JRocker3]

Originally Posted by neonnblack

running a cts catless dp. resonator deletes into the mpe muffler. sounds great. i also have an electric cutout in it to really make some noise.

also running mhd stg2.

Any sound clips to share?

What do you think of the stage 2 tune?

[neonnblack]

Originally Posted by JRocker3

Any sound clips to share?

What do you think of the stage 2 tune?

that's with the cutout open, a quick vid i did the other night. I'll get one of it closed tomorrow.

I'm liking it a lot much better than stock.

[mike@x-ph.com]

Originally Posted by JRocker3

Anyone have any recommendations based upon experience?

I'm thinking:

Evolution Racewerks catless DP and AWE exhaust (I'm running MPPSK now, and want to ditch the valves)

Bootmod Stage 2

Seems like the most straightforward route... but I'd love to know some feedback!! Thanks!

Good choice

[Wires]

I've been running the ER DP for about 1.5 months with zero CEL FYI. Very happy with it.

[JRocker3]

Originally Posted by Wires

I've been running the ER DP for about 1.5 months with zero CEL FYI. Very happy with it.

Good to know... are you running an aftermarket midpipe or exhaust?

Also... I wonder how the stock tune manages the extra flow created by the downpipe? I wonder if it simply throttles back to accommodate? At what point do modifications without a tune start to exceed the limits of the stock engine management?

[kern417]

Originally Posted by JRocker3

Good to know... are you running an aftermarket midpipe or exhaust?

Also... I wonder how the stock tune manages the extra flow created by the downpipe? I wonder if it simply throttles back to accommodate? At what point do modifications without a tune start to exceed the limits of the stock engine management?

It doesn't do anything. It'll probably spool a bit quicker but it doesn't make much power without a tune because the stock tune isn't changing anything.

[JRocker3]

Originally Posted by kern417

It doesn't do anything. It'll probably spool a bit quicker but it doesn't make much power without a tune because the stock tune isn't changing anything.

Yeah, not suggesting it makes more power, simply wondering at what point do bolt on modifications push the engine parameters beyond the controllable limit of the stock tune.

For instance - and this is purely hypothetical - if the car were exposed to much larger volumes of oxygen, how much could the stock tune adjust to keep the AFR in check? There has to be targets for that sort of thing... I'm sure it would dump air from the turbo before continuing to push it into the intake...

So with regards to the downpipe... if the turbo can now spool quicker then it can push more air, sooner. But, if the ECU recognizes this extra air and cannot supply the appropriate fuel (due to the limits of whatever the stock tune sets) then what happens?

And I suppose these questions apply to any engine control, or tune.

I know I'm going off topic of my own thread but these are the sorts of questions I'm very curious about. Any tune has its limits; as defined by the tuner. And certainly there would be times that the ambient conditions would push the cars ECU into territories it maybe wasn't programmed for... and I'm curious what happens at that point.

Similar to what happens if you try and open a .mov file on a PC without the necessary software ... the PC doesn't run, it stops in its tracks until you tell it what to do: either download the necessary software or kill the command.

Maybe to get back on track then - with these questions in mind - what parameters is a seasoned tuner looking at to say that a tune is good, or safe, or efficient, etc.

[kern417]

Originally Posted by JRocker3

Yeah, not suggesting it makes more power, simply wondering at what point do bolt on modifications push the engine parameters beyond the controllable limit of the stock tune.

For instance - and this is purely hypothetical - if the car were exposed to much larger volumes of oxygen, how much could the stock tune adjust to keep the AFR in check? There has to be targets for that sort of thing... I'm sure it would dump air from the turbo before continuing to push it into the intake...

So with regards to the downpipe... if the turbo can now spool quicker then it can push more air, sooner. But, if the ECU recognizes this extra air and cannot supply the appropriate fuel (due to the limits of whatever the stock tune sets) then what happens?

And I suppose these questions apply to any engine control, or tune.

I know I'm going off topic of my own thread but these are the sorts of questions I'm very curious about. Any tune has its limits; as defined by the tuner. And certainly there would be times that the ambient conditions would push the cars ECU into territories it maybe wasn't programmed for... and I'm curious what happens at that point.

Similar to what happens if you try and open a .mov file on a PC without the necessary software ... the PC doesn't run, it stops in its tracks until you tell it what to do: either download the necessary software or kill the command.

Maybe to get back on track then - with these questions in mind - what parameters is a seasoned tuner looking at to say that a tune is good, or safe, or efficient, etc.

The tune does not have limits like what you're thinking. If anything, the sensors are what you should be worried about. That's why people upgrade MAP sensors, MAF housings, and other items to keep up with the new requests that come with a tune.

The turbo is the main choke point. With stock boost levels, you will not overwhelm any of the sensors that feed information, so there should be no concerns about bolt ons. Even with a bolt on tune our stock electronics are fine.

The difference with your PC example is, in the sense of our cars, you have all of the applications that can run the software you want. In fact, you probably have a lot of bloatware you're not interested in. Adding bolt ons is like deleting those programs for others that are lighter weight. They may open more quickly or run more smoothly because they're properly dialed for your purpose without the fluff, but that doesn't mean it's overwhelming the CPU. It's just allowing it more freedom to run at max efficiency.

The only thing you should be weary of is untested hardware. The sensor inputs are still critical, so an intake that messes with your MAF readings or a downpipe that puts your 02 sensor in the wrong location can definitely cause issues. But the big names that you see mentioned on the forums don't have those issues. That would be more of a concern with parts from eBay or Alibaba.

[JRocker3]

Originally Posted by kern417

The tune does not have limits like what you're thinking. If anything, the sensors are what you should be worried about. That's why people upgrade MAP sensors, MAF housings, and other items to keep up with the new requests that come with a tune.

The turbo is the main choke point. With stock boost levels, you will not overwhelm any of the sensors that feed information, so there should be no concerns about bolt ons. Even with a bolt on tune our stock electronics are fine.

The difference with your PC example is, in the sense of our cars, you have all of the applications that can run the software you want. In fact, you probably have a lot of bloatware you're not interested in. Adding bolt ons is like deleting those programs for others that are lighter weight. They may open more quickly or run more smoothly because they're properly dialed for your purpose without the fluff, but that doesn't mean it's overwhelming the CPU. It's just allowing it more freedom to run at max efficiency.

The only thing you should be weary of is untested hardware. The sensor inputs are still critical, so an intake that messes with your MAF readings or a downpipe that puts your 02 sensor in the wrong location can definitely cause issues. But the big names that you see mentioned on the forums don't have those issues. That would be more of a concern with parts from eBay or Alibaba.

Got it, that makes more sense, thanks!

[Stampe]

25 hp more with only downpipe !!! no ecu

[Wires]

Originally Posted by JRocker3

Good to know... are you running an aftermarket midpipe or exhaust?

Also... I wonder how the stock tune manages the extra flow created by the downpipe? I wonder if it simply throttles back to accommodate? At what point do modifications without a tune start to exceed the limits of the stock engine management?

Stock midpipe, Active Autowerke cat-back exhaust (that is more for sound than anything).

All these modern engines use the MAF (Mass Air Flow) sensor to measure the air in to apply the proper amount of fuel. You will eventually reach the fuel cap in a stock tune, but you'd never see it from a DP and exhaust.

You really need the tune to unlock the potential of the DP. Anything after that (midpipe and exhaust) are just for the obnoxious factor.