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View Full Version : nDBW + K03 + APR 91 = ??? PSI?



ct1.8t4me
04-15-2007, 07:37 AM
OK - I am running what I have in my signature, basically:

K03 nDBW (98.5)
APR 91 ECU
ATP 3" Test Pipe
2.5" Custom Exhaust
FMIC w/ 2" intercooler piping
Custom Heatshielded intake
710N
MBC


Without the MBC, I would get basically right around 15-16 PSI consistently with the APR Chip. The MBC I have is basically a pressure regulator from Home Depot, tee'd in to the wastegate vacuum line, bleeding off a certain amount of the air to atmosphere. With this setup, I am getting 17-18 PSI, but drivability could be better - the boost comes on way too strong in lower RPMS and makes the car a little twitchy in the acceleration department.

I would like to hear people with similar setups talk about what they are boosting, and how they are getting there.

IMPORTANT: I know that GIAC chips are more aggressive, etc. but that is of no use to me in this thread. I am really trying to get a feel for folks who have similar setups (nDBW, APR 91 specifically) and what they are running boost-wise.

Thanks for the info!

Oricle
04-15-2007, 09:31 AM
15-16 pounds is normal on a K03+APR tune. I was right about there as well with a 3" exhaust and an APR tune. This reminds me I need to find my old APR chip and put it out on ebay.

superman_006
04-15-2007, 09:36 AM
You can run the MBC between the N75 valve and the wastegate accuator to help with boost spikes, Also if your vacum hose is too long it will have alot of spiking issues also

superman_006
04-15-2007, 01:24 PM
Here are some other ways to install your boost controller
http://i130.photobucket.com/albums/p276/superman_006/mbc1.jpg
http://i130.photobucket.com/albums/p276/superman_006/parralle.jpg

dualaudi
04-15-2007, 01:48 PM
I was hitting 15-16 psi with a similar set up... I tossed in a h-valve and was hitting17-19 psi...

ct1.8t4me
04-15-2007, 05:22 PM
Here are some other ways to install your boost controller
http://i130.photobucket.com/albums/p276/superman_006/mbc1.jpg

I've tried this way - I might switch back because I think it was a little smoother than the bleed that I am using now. This way the N75 ultimately still controls things, where with my current setup, I get a big initial hit as the pressure is bled off by the MBC/bleed and then the N75 starts to take care of business - this is why I say it's a little twichy.

http://i130.photobucket.com/albums/p276/superman_006/parralle.jpg

I'm pretty sure this method is used to control spikes but it doesn't necessarily let you bump the boost up at all.

ct1.8t4me
04-15-2007, 05:27 PM
So - anyone out there running 20+ on an APR 91 nDBW? I guess that's the question I'm looking for.

I know that if I crank my MBC open I can get to 20 no problem, the issue is the drivability at low RPM/speeds. If I am really mellow on the throttle then get on it once I am at speed it's ok - but for driving around town with the MBC set up for 20 it really sucks.

I'm thinking an EBC would probably be able to gradually ramp the boost up, but I'm not prepared to invest in that just yet...

superman_006
04-15-2007, 05:28 PM
The paralle version, (bottom) should still also control you boost because your still leaking off vacum on the wastegate, I dont think it would do much if you have a spring type with the check ball in it

Oricle
04-15-2007, 05:31 PM
So - anyone out there running 20+ on an APR 91 nDBW? I guess that's the question I'm looking for.

I know that if I crank my MBC open I can get to 20 no problem, the issue is the drivability at low RPM/speeds. If I am really mellow on the throttle then get on it once I am at speed it's ok - but for driving around town with the MBC set up for 20 it really sucks.

I'm thinking an EBC would probably be able to gradually ramp the boost up, but I'm not prepared to invest in that just yet...


You want to get a different N75 valve. ecstuning.com

You sould gain a couple psi off of it.

SeanF
04-15-2007, 05:34 PM
i dont think you can turn up the boost with the controller in parallel. it will take the path of least resistance, which at that point would be through the n75 to the wastegate...

superman_006
04-15-2007, 06:14 PM
http://i130.photobucket.com/albums/p276/superman_006/parralle-1.jpg

How about this one

AudiSport12
04-15-2007, 06:49 PM
i hit 21-22 with my APR with almost the same mods as you. but im running the stock SMIC (FMIC goes in this week)

ct1.8t4me
04-15-2007, 06:55 PM
That's another thought - I installed the ATP Testpipe at the same time as the FMIC - so I never had a chance to see the difference of one or the other.

ct1.8t4me
04-16-2007, 04:54 PM
Anybody else want to chime in?

speedydragon
04-16-2007, 05:24 PM
turbo lag is more noticable. i usually switch it back to stock mode if i'm driving in the city. and 91 mode when i'm on the freeway.

ct1.8t4me
04-16-2007, 06:57 PM
I'm thinking about switching to a ball/spring type MBC. My thinking is that at low pressures, the N75 will take care of business and my part throttle drivability will be largely controlled by the ECU, and then when I get on it, the MBC will open and give me a little more at the top. Right now the MBC is just basically wide open so I am getting poor low speed/rpm drivability as the turbo boosts too high for the conditions the ECU expects.

Does this sound like a good plan to anyone out there?

Burntaudi
04-17-2007, 06:52 AM
K03+APR+FMIC=Slow. I had a similar setup on my car in the past. The car was fine with K03+APR+Exhaust as soon as I added a front mount I saw a pretty signicant pressure drop. I know you don't wanna hear it but I switched to GIAC right after I added the FMIC because they have K03+FMIC file. The car felt like it should after switching to GIAC.

ct1.8t4me
04-17-2007, 06:55 AM
K03+APR+FMIC=Slow. I had a similar setup on my car in the past. The car was fine with K03+APR+Exhaust as soon as I added a front mount I saw a pretty signicant pressure drop. I know you don't wanna hear it but I switched to GIAC right after I added the FMIC because they have K03+FMIC file. The car felt like it should after switching to GIAC.

The way I setup my FMIC - with 2" piping - I did not lose any boost pressure according to the gauge.

Burntaudi
04-17-2007, 11:14 AM
Did you ever do a pressure test? Your boost seems a little low.