Highest proven downpipe gains

[AstonMartian777]

Originally Posted by IANNUZZI

You are talking out of your A$$, not all turbo cars make more power with an aftermarket downpipe. The 550i made considerably less power with one. In case your wondering it has a 4.4L TT engine similar to the S63TU. It made all of its gains from the BMS piggyback. And another thing, a downpipe installation without a tune is useless, it is a hit or miss as you have no control over A/F ratios with a piggyback. Russian roulette anyone?

Ok, tuning is the most important part of this I agree, that's why there are 2 files with these new flashes 1 for DP's and 1 for stock.Stock with a flash makes about 30whp less than the one with the downpipe because they add a little more fuel to compensate the extra air. Now the difference between BMW ( very smart dme ) and other cars like WRX STI is that DME can slowly adopt to the extra air if you adopt it properly, and after multiple long, high end pulls it will adopt, it will still be a little lean but it will be enough to make that extra power, for example if you add a dowpipe to a wrx and you drive it before tuning it you will most likely blow your motor, bmw doesn't need specific dyno tune to every single after market part because the dme is smart enough, just look at n54, people run same map FBO, (fmix, cai, exhuats, dp ) and can run same map on a car with just a downpipe, and the cars don't blow up ( to a certain extend ofcourse ), so the deal with the 550 could've been that they expected downpipe to make instant power as it would on n54 lets say but it was just too much air right away and DME pulled timing ( my guess ), I'm not sure about 550's dme or how lean they run with jb alone to estimate why the car made less power, maybe it ran too lean as it is, with added 3 or 4 psi, maybe they used 91 octane as well, ( they never logged timing) but the fact of the matter is that if you add a higher flowing exhaust to a turbo car that has a raised boost, and tuned properly, it will always, ALWAYS, always make more power.

[Spinny02]

Originally Posted by IANNUZZI

The aftermarket downpipe for a 550i makes less power than stock, so you are the one that does not know what you are talking about. The gains all came from the BMS unit.

It may on an non tuned engine but it should not. If one was tested I would make sure they used new gaskets and crush rings or you would get a leak and loose power. No cats = more flow less restriction = power (too much flow can slow turbos down just a bit but only at very low power inputs)

[r33_RGSport]

@E92TTKING , PM me if you are still in the market and I will show you the secret.

[Mbmw5]

Originally Posted by IANNUZZI

Personally, I don't think the downpipes are worth it for the small hp gains vs smell etc....

Gain on mine was 40 hp. Enzo custom down pipes. Sounds great. Very loud on cold start up though. Good thing it's not my daily driver. Although if it's summer and the sun is out Im driving it every day. Oh exhaust fumes are bad too with windows down.

[M5TXGuy]

I wonder if a newly flashed ECU could also program for no cold starts. If there are no cats, there is no need for a cold start. Am I correct with that assumption?

[dmetuning]

Originally Posted by AstonMartian777

I don't have to show you shit, all i know is when I see you on the highway I will blow your doors off.

lmfao

[boots]

Originally Posted by M5TXGuy

I wonder if a newly flashed ECU could also program for no cold starts. If there are no cats, there is no need for a cold start. Am I correct with that assumption?

Naw. I already asked about removing the cold start. It cannot be done at this time.

[6spdterror]

Originally Posted by boots

Naw. I already asked about removing the cold start. It cannot be done at this time.

Btw boots you were actually correct......the fumes get less the more you drive it. The fumes were terrible when i just got it done but now its really not that bad

[boots]

thanks. it's just breaking in the pipes. Once all the internal stuff in the pipes is coated my guess, the fumes get less and less. It has nothing to do w getting used to it. My wife drives the M and if it were present she would let me know. Hell I don't want to backfire and stand in the same spot. Lol ew weeee

[IANNUZZI]

The Original Question is asking for "Proven" gains from downpipes.

There are no proven gains with ONLY a downpipe install on S63tu. Dyno maps don't cut it for me as there is manipulation; you can see it with the tunes ranging from 600 to lol........800ft/lbs :BS. Anyone can see the dyno manipulation.
S63tus that should be gaining 3-4 mph with downpipes alone are gaining negligibly. They are however gaining 3-4 mph with piggybacks. 1/4 mile and trap speeds count, 60-130mph times count.

A downpipe install on n63tu with no other mods yields less power, which makes me further doubt gains on the s63.

The seat of pants gains some of you may be experiencing come from the free flowing characteristics of the downpipe allowing boost creep until the wastegates stabilize boost, so between 2-4k rpm. The gains from the downpipe are negligible at full throttle because there is enough constant exhaust flow and boost is maintained between shifts on the dct, so no spike allowing higher torque/power during the spike. The stock downpipe is a high flow unit that can flow everything the engine can throw at it at full throttle running stock boost.

Yes, I am well aware of the bpu and fbo philosophy, but evidence on these platforms shows strong evidence that a downpipe is worthless without a tune and may actually be detrimental as seen on the n63tu.

[greentrbo95gst]

Removing cats on a car with forced induction car generates huge gains. I went from 11.3 to 11.07 and 3mph difference.

[greentrbo95gst]

Originally Posted by M5TXGuy

I wonder if a newly flashed ECU could also program for no cold starts. If there are no cats, there is no need for a cold start. Am I correct with that assumption?

That would be great, but i don't think it's possible per my conversation with Bruno (BR).
You can get rid of the crazy loud noise by holding your foot on the accelerator at 2k rpms for 10 seconds as soon as you start.

[greentrbo95gst]

Originally Posted by 6spdterror

Btw boots you were actually correct......the fumes get less the more you drive it. The fumes were terrible when i just got it done but now its really not that bad

Lol, your lungs are just used to them. Try checking them for carbon levels or something like that.

[Mbmw5]

Originally Posted by 6spdterror

Btw boots you were actually correct......the fumes get less the more you drive it. The fumes were terrible when i just got it done but now its really not that bad

Funny I noticed it too. The fumes are not that bad on mine now too after putting some miles on. Weird. I'll have to ask Enzo about that.

[6spdterror]

Originally Posted by Mbmw5

Funny I noticed it too. The fumes are not that bad on mine now too after putting some miles on. Weird. I'll have to ask Enzo about that.

Enzo told me the same thing. He said drive it for a while and see becuase it gets better. I was seriously considering getting the catted and selling the catless!

[desant89]

I am dying to get downpipes, but am really worried about the smell. Especially since I have a convertible. I removed cats from an R1, and ended up getting rid of it cause I could not take the smell anymore.

[MCarsFan]

Sounds like the smell goes away over time once the dps get covered in carbon..

[boots]

Originally Posted by greentrbo95gst

Lol, your lungs are just used to them. Try checking them for carbon levels or something like that.

I'm at level 10. When I get to 10+ I'll need a doctor. Lol

[desant89]

Anyone have an M6 convertible with catless downpipes? I did see a few say the smell goes away, but I have seen just as many say it does not. Just do not want to take on the expense of doing it, and need to have them removed at some point. Of course I would love the power, and I am dying to hear my turbos spool up and down, but am just a little skeptical.

[M5TXGuy]

Originally Posted by desant89

Of course I would love the power, and I am dying to hear my turbos spool up and down, but am just a little skeptical.

The smell hasn't gone away for me. Maybe its not as strong as initially or I'm just more used to it, either way, it stinks. You could go with the AMS high flow cats instead. Some better sound and performance, but not the catless smell or performance.

[desant89]

Love the thought of the high flow catted DP's, but 3k seems like a ton for those! Has to be a better option....