Quietest downpipes

[gpennell0812]

Does anyone know which downpipe would be the quietest? I don't really want the car to be loud, just want the extra performance. Also, do any of the downpipes that keep the cats pass CA emission testing?

[TopJimmy]

To be honest the stock cats are not that restrictive...unless you want pops and flames.

Next best is a set of quality sport-cats (high flows) so you have little cat restriction and you remove some of the tailpipe stink.

[gpennell0812]

Originally Posted by TopJimmy

To be honest the stock cats are not that restrictive...unless you want pops and flames.

Next best is a set of quality sport-cats (high flows) so you have little cat restriction and you remove some of the tailpipe stink.

I'm mainly wanting it to have the option of doing BM3 stage 2. Not really looking to increase the pops or burbles from the exhaust.

[E92Roni]

Originally Posted by gpennell0812

I'm mainly wanting it to have the option of doing BM3 stage 2. Not really looking to increase the pops or burbles from the exhaust.

You can run a stage 2 OTS map with stock downpipes as long as you keep the burbles soft.

[TopJimmy]

I've even run Stg2 E30 on stock cats no probs. As said, keep burbles off or to a minimum (<4agg).

[gpennell0812]

Is the valve that controls the burbles in the down pipe or further back in the exhaust?

Is there any additional power gain running stage 2 with an aftermarket downpipe vs stock running stage 2?

[Reprosal]

I am wondering if you can even control the pops on a JB4 vs flash. Otherwise I may just try the stage 2 with 91 octane (highest available here) and catback exhaust.

No worries about CEL and emissions at all then.

[gpennell0812]

I wish BM3 had a multimap where you could switch back and forth on the fly between stock, stage 1, and stage 2 all with the same octane. Since 91 octane is the highest we can get in CA besides race gas, the multimap of the same stage with different octanes isn't really that beneficial.

[Reprosal]

The map won’t increase gains on stage 2 vs stage 1 with the same fuel?

[hellokitty]

I have ARM resonated downpipes and they are pretty quiet during normal driving.

With valves closed, it sounds just like stock.

When you go WOT then hell breaks loose haha

[Mike.]

I would say some sort of resonated pipes.

[mike@x-ph.com]

The Evolution Racewerks catted downpipes are not too loud but give the car a nice deep mid-range tone. It's going to be quieter than any catless option, even resonated ones.

But no aftermarket downpipes are legal in CA

[gpennell0812]

Originally Posted by Reprosal

The map won’t increase gains on stage 2 vs stage 1 with the same fuel?

Then what is the point of BM3 stage 1 vs stage 2?

[gpennell0812]

Originally Posted by mike@x-ph.com

The Evolution Racewerks catted downpipes are not too loud but give the car a nice deep mid-range tone. It's going to be quieter than any catless option, even resonated ones.

But no aftermarket downpipes are legal in CA

Good to know. Thanks for the info! I've seen where some people keep the stock and swap them out before being smogged, but that seems like too much of a hassle.

[mike@x-ph.com]

Originally Posted by gpennell0812

Then what is the point of BM3 stage 1 vs stage 2?

stage 2 makes more power.


Stage 1 91: up to 20%HP / 22%TQ
Stage 1 93: up to 22%HP / 23%TQ
Stage 2 91: up to 23%HP / 26%TQ
Stage 2 93: up to 24%HP / 26%TQ
Stage 2 E30: up to 26%HP / 26%TQ
Stage 2 Racegas: up to 26%HP / 26%TQ

[gpennell0812]

Originally Posted by mike@x-ph.com

stage 2 makes more power.


Stage 1 91: up to 20%HP / 22%TQ
Stage 1 93: up to 22%HP / 23%TQ
Stage 2 91: up to 23%HP / 26%TQ
Stage 2 93: up to 24%HP / 26%TQ
Stage 2 E30: up to 26%HP / 26%TQ
Stage 2 Racegas: up to 26%HP / 26%TQ

Thank you! I had actually just found that on the protuning freaks website. So the gains from stage 1 to stage 2 seem pretty minimal for an otherwise stock car. I guess the minimal gains and hassle of CA emission restrictions make it less tempting to get an aftermarket downpipe.

[AlterZgo]

Originally Posted by gpennell0812

Is the valve that controls the burbles in the down pipe or further back in the exhaust?

Is there any additional power gain running stage 2 with an aftermarket downpipe vs stock running stage 2?

The valves don't control the burbles per se. The burbles happen through injecting additional fuel on decelaration and adjusting the spark timing. With that said, if you close the exhaust valves, it will muffle some of the burble sounds as it routes the exhaust gasses through the muffler instead of bypassing the muffler.

The exhaust valves are located in the back of the car to the right and left sides of the muffler canister and not anywhere close to the downpipes.

There is additional power running stage 2 with downpipes vs. stage 2 with stock cats because the exhaust is less restrictive with downpipes and downpipes alone, with stock or stage 2 tune, would result in more power.

[mike@x-ph.com]

Originally Posted by gpennell0812

Thank you! I had actually just found that on the protuning freaks website. So the gains from stage 1 to stage 2 seem pretty minimal for an otherwise stock car. I guess the minimal gains and hassle of CA emission restrictions make it less tempting to get an aftermarket downpipe.

Agree, that's why we removed the downpipes from our combo deals. the combo now consists of the tune + charge pipes for stage 1 users. We offer the catted downpipes separately

[AlterZgo]

Originally Posted by gpennell0812

Thank you! I had actually just found that on the protuning freaks website. So the gains from stage 1 to stage 2 seem pretty minimal for an otherwise stock car. I guess the minimal gains and hassle of CA emission restrictions make it less tempting to get an aftermarket downpipe.

I've never run a stage 2 tune, but when comparing any power adders, it's important to look at the actual power and torque curves as looking at maximum numbers alone may be misleading.

Here's a dyno chart from the BM3 website comparing stock vs. stage 1 vs stage 2 tunes. While there is a less than 15 peak hp difference btw the two tunes (503.37 hp vs. 488.72 hp), if you look at the graph, you will see at different parts of the power curve that the stage 2 tune is consistently making a good 20-50 more hp, particularly lower in the RPM range. At about 3250 rpm, there is a huge 100+ ft/lb torque difference btw stage 1 and stage 2. That will make the stage 2 tune feel noticeably stronger than stage 1 in day to day driving.

With that said, given how fucked up California is now with emissions testing, smog referees, and cops pulling over people with cars with loud or modded exhausts and intakes, I would never remove the stock cats.

[gpennell0812]

Originally Posted by AlterZgo

I've never run a stage 2 tune, but when comparing any power adders, it's important to look at the actual power and torque curves as looking at maximum numbers alone may be misleading.

Here's a dyno chart from the BM3 website comparing stock vs. stage 1 vs stage 2 tunes. While there is a less than 15 peak hp difference btw the two tunes (503.37 hp vs. 488.72 hp), if you look at the graph, you will see at different parts of the power curve that the stage 2 tune is consistently making a good 20-50 more hp, particularly lower in the RPM range. At about 3250 rpm, there is a huge 100+ ft/lb torque difference btw stage 1 and stage 2. That will make the stage 2 tune feel noticeably stronger than stage 1 in day to day driving.

With that said, given how fucked up California is now with emissions testing, smog referees, and cops pulling over people with cars with loud or modded exhausts and intakes, I would never remove the stock cats.

Oh wow, I've never looked at it that way. Thanks for pointing that out. In sure that would feel like way more than a 3-6% gain in power from stage 1 to stage 2

[TopJimmy]

Originally Posted by gpennell0812

Is the valve that controls the burbles in the down pipe or further back in the exhaust?

Is there any additional power gain running stage 2 with an aftermarket downpipe vs stock running stage 2?

There is no valve that controls burbles...the tune blows some fuel mix past the exhaust valve so it pops in the manifold/turbo/exhaust.

Not much gains going from OEM to catless, maybe 5-20HP depending on your other bolt ons. With bigger turbos the difference is a little more.

[edwinm3]

oem, best downpipes, no smell