Speed Density airflow difference

JohnBradley · Oct 20, 2009, 03:47 PM

I couldnt find the thread where I talked about this car before, so I decided to make one and show the power difference. I am also going to add the logs from tuning this car at the time to show what we were running into.

June/July-

At 26psi with a custom cold air 3" MAF setup the car made 480.39 and this was at the edge of timing (intermittent 1s and 2s). Taking the filter off with no changes to the tune (open turbo) it immediately picked up power and went to 493.09. It was late so we left, came back the next morning early and made some pulls. We installed a 4" filter pipe assembly and were able to get 2 more degrees into it and ended up at 512.

Logs to follow.

CMB · Oct 20, 2009, 03:51 PM

So you switched to SD (stock ECU) and these were the gains from just pulling the Maf out of the equation? Impressive

0xDEAD · Oct 20, 2009, 04:10 PM

Interesting. My gains were much smaller but I am also on a stock turbo and unfortunately I added a downpipe between track visits. With similar air going from MAF to SD and from stock downpipe to a 3" downpipe I gained 2.4mph in the quarter mile. I would guess 5-10 hp on a stock turbo style car.

JohnBradley · Oct 20, 2009, 04:19 PM

Dave posted earlier about 55whp from removing a MAF and fixing/replacing a BOV, so I wanted to share that we have seen very similar gains (well MAF removal) to back him up.

On the stock turbo we have seen a best of 11whp from switching to SD without cams, and one car that really seems to have picked up about 15whp over where an S2'd VIII would normally otherwise be.

0x, your 2.4 would be about 25whp going by the old rule of thumb so your guess of 5-10whp seems about right to me.

CMB · Oct 20, 2009, 04:24 PM

^ John, the 55 HP David gained were not from the switch to SD as he had already switched to the AEm and documented those gains. He said (once the AEM was in) once he switched the BOV and intake pipe he then realized another 55 HP.

03whitegsr · Oct 20, 2009, 04:37 PM

Oh, so you added a 4" intake and picked up power over the open turbo?

In David's thread, I thought you were saying just some extra tuning on the open turbo got you up to 510 WHP.

I'd still like to see an AEM vs. a Speed Density patched stock ECU shootout.
All out power...
And driveability/fuel economy...

tephra · Oct 20, 2009, 04:48 PM

good stuff.

SD was always going to benefit big turbo setups more than stock setups..

davidbuschur · Oct 20, 2009, 04:52 PM

Nice comparison. Looks like we've seen similar experiences.

JohnBradley · Oct 20, 2009, 05:07 PM

Quote:

Originally Posted by 03whitegsr

Oh, so you added a 4" intake and picked up power over the open turbo?

In David's thread, I thought you were saying just some extra tuning on the open turbo got you up to 510 WHP.

I'd still like to see an AEM vs. a Speed Density patched stock ECU shootout.
All out power...
And driveability/fuel economy...

Our 4" intakes arent very restrictive. The 510/512 (darn my semi faulty memory) would have happened open turbo but I dont typically like running turbos open. The other thing is putting the filter on it moves the inlet out of the path of the hot air coming off the radiator and everything under the header/WG dump.

Intake-

Vs the 3" it had-

0xDEAD · Oct 20, 2009, 06:24 PM

I should note that I'm still using the stock rubber intake snorkel. I just bought a PVC reducer from Lowes to replace the MAF, it is a $3 part, works great.

My BOV isn't leaking to 28psi during a boost leak test. Are you seeing a power gain just switching out a seemingly non leaking BOV? I'm running the stock metal evo IX BOV, not crushed, no gus mod, doesn't seem to need it.

rolly1818 · Oct 20, 2009, 08:02 PM

Quote:

Originally Posted by 0xDEAD

I should note that I'm still using the stock rubber intake snorkel. I just bought a PVC reducer from Lowes to replace the MAF, it is a $3 part, works great.

My BOV isn't leaking to 28psi during a boost leak test. Are you seeing a power gain just switching out a seemingly non leaking BOV? I'm running the stock metal evo IX BOV, not crushed, no gus mod, doesn't seem to need it.

my stock evo ix BOV leaked at 10 psi - yes i pressure tested it.

i replaced it and it was an instant improvement. to justify it on my DD map i could only get 10/11 psi on WG boost, when i changed BOVs i got 12 psi. NOTE: i tightened some IC piping as well, but the BOV was leaking badly as per my test.

nice thread Aaron, i am currently looking for a neat MAFless intake setup for the stock turbo. if you got one let me know.

-Ravaal

scheides · Oct 21, 2009, 08:58 AM

Hrm. I have s spare maf housing, gutting the hell out of it would be a cool sleeper look and potentially see the same benifits (on a stock/stock appearing turbo setup).

Awesome dyno numbers Aaron! I've been waiting for info like this. Def tempting.

JohnBradley · Nov 20, 2009, 01:51 PM

Guess it was actually the end of May that we did this test not June/july.