[Mannix]

Dyno results:

Sound comparison:

[BKBMW335I]

Are you somewhere where it's very cold??

[Joey911]

I thought all N55 is LCI? Why you have pre-LCI rear bumper?

[rob24ert]

fantastic videos!! very excited to install my DP soon

[Peen]

Put one on this weekend. Running PPK, JB4 ISO and E50 fuel, Map 7. Not sure if I can feel any difference. 20HP might not be extremely noticeable to me.

Sure can hear the PPK though!

[Mannix]

Originally Posted by BKBMW335I

Are you somewhere where it's very cold??

No.

Originally Posted by Joey911

I thought all N55 is LCI? Why you have pre-LCI rear bumper?

What is "LCI"?

[BKBMW335I]

Originally Posted by Mannix

No.

The reason I was asking because your car is putting out a lot of smoke and it shouldn't be putting out that much IMHO.

[Mannix]

Originally Posted by BKBMW335I

The reason I was asking because your car is putting out a lot of smoke and it shouldn't be putting out that much IMHO.

There's no cat.

[mike@x-ph.com]

Great video

[mike@x-ph.com]

Originally Posted by rob24ert

fantastic videos!! very excited to install my DP soon

Which DP did you get?

[Mannix]

By the way, I bought my downpipe from Mike@x-ph. I contacted him before I bought it, and completed the transaction online. It was easy and there were no problems. I also got emails regarding shipping, expected delivery, etc...

[Mannix]

Originally Posted by rob24ert

fantastic videos!! very excited to install my DP soon

Do you plan to perform before and after dyno measurements?

I'm really interested to see what kind of gains you'll see with a catted downpipe.

[BKBMW335I]

Originally Posted by Mannix

There's no cat.

Yes I know that, I don't have cats either and I don't put out anywhere near that amount of smoke.

[mike@x-ph.com]

Originally Posted by Mannix

By the way, I bought my downpipe from Mike@x-ph. I contacted him before I bought it, and completed the transaction online. It was easy and there were no problems. I also got emails regarding shipping, expected delivery, etc...

Thank you for the kind words Mannix

[rob24ert]

Originally Posted by mike@x-ph.com

Which DP did you get?

Local seller had the bms/n54tuning dp. I'd rather ar since its larger for more spooling noise but i got this for a good price. Waiting for a local ets charge pipe or I will order one.

Originally Posted by Mannix

Do you plan to perform before and after dyno measurements?

I'm really interested to see what kind of gains you'll see with a catted downpipe.

No dump, just how it feels. Then I will install my jb4 when I get a charge pipe

[n55e90]

I didn't feel a difference when i installed my downpipe either lol

[mike@x-ph.com]

Originally Posted by n55e90

I didn't feel a difference when i installed my downpipe either lol

Are you tuned, if so did you change your map?

DP will add performance without the need of any adjustments, but if paired with the right tune you will gain a lot more power

[Mannix]

Originally Posted by n55e90

I didn't feel a difference when i installed my downpipe either lol

The only difference I felt was throttle response. But that might be psychological.

The catless downpipe did increase torque by 7% at most. But that is an almost insignificant amount to feel with the butt dyno.

Here is a graph of comparisons:

Dinan Stage 2 software only (red)
Dinan State 2 software + Dinan intercooler (blue)
Dinan Stage 2 software + Dinan intercooler + catless downpipe (green)

These are averages. I made 4 dyno runs with the Stage 2. I included only data from 2500 to 6700 rpm. Why? Because in that range, a 2nd order line fits the data VERY well. No need to use a higher order line.

If you'll notice in my other plots, the torque/hp curves take a nose dive at 6800 rpm. That screws up the fit of the 2nd order line. I think because the computer is cutting boost and preparing to shift (I have an automatic).

Also, below 2500 rpm, the torque (and hp) rise quickly. Again, including this requires higher order lines to fit the data. Besides, you're only operating below 2500 in first gear off the line. So who cares about it?

I made 3 (or 4) dyno runs for each mod. There were differences as much as 10 hp and 10 ft-lbs between the best and worst raw data lines. The 2nd order fits perfectly within those ranges. No need for a higher order fits.

One more argument for the 2nd order line: You can convert that torque curve to rear wheel force for each gear (by multiplying by gear ratios and dividing my rear wheel radius), and acceleration (by dividing my mass). Then you can plot acceleration vs. velocity. Then you have acceleration as a function of velocity. You can convert this to a distance vs. time plot using a differential equation. With a 2nd order equation for acceleration, you can solve the differential equation analytically. If you use a higher order curve, then you'll need to solve it numerically, using Euler or Runga-Kutta method. This can predict your quarter-mile ET.

So I fitted a 2nd order line through each dyno run set and averaged it.

For Stage 2 + intercooler, I did the same with 3 dyno runs. Ditto for Stage 2 + intercooler + catless DP.

Notice the intercooler only showed gains at higher RPM. Also keep in mind this is on the dyno. And even though they have fans blowing, are they enough to take advantage of any benefit the intercooler might offer?

[Mannix]

Plot didn't attach to previous post. Here it is.