DSMLink, VPC Questions

sleepydsm · 01-01-2006

I miiiggghhhttt just be getting another car... and I'm planning ahead...

You need to keep some sort of MAS when using DSMLink, correct?

Bare with me, I don't know too much about the VPC.
When looking at VPC's for sale, most have some sort of injector chip ie. "550cc" chip. Does this mean for that "chip" you can only use the 550cc?

Do you just get a different "chip" to run larger injectors, or is that just a "baseline" and you adjust the VPC to compensate for injectors bigger than 550cc?

What does the GCC do in conjunction with the VPC?
Thanks.

**Shane@DBPerformance** · 01-01-2006

DSMLink assumes a Karmen MAS. You could use MAFT or VPC to convert from their metering forms to Karmen for use with the DSMLink. The VPC has some tables built in for fueling, you are supposed to run a 550 chip with 550 injectors, but you could use a different chip with different injectors and do some tuning of the gain on it and/or with another unit like a GCC/S-AFC/DSMLink. Normally with DSMLink, you want to be based off of 450cc injectors and then do all the compensations internally with the DSMLink. The way DSMLink handles larger injectors is far superior to how you do it with something like an S-AFC, MAFT or VPC. The VPC is a serious hack of a device though, so you could run into some weird things like the airflow metering maxing out, because the VPC thinks it needs to avoid fuel cut, even though a DSMLink does a better job at that, or just maxing out the VPC map sensor.

GCC is like the old school 5-knob AFC. A lot of people use an S-AFC in conjunction with a VPC, instead of the GCC.

sleepydsm · 01-01-2006

Thank you Shane. I guess it'll be DSMLink, unless I win the lottery

**Goat Blower** · 01-02-2006

Everyone uses speed density with the VPC, how can you max out airflow metering?

I'd still take the VPC over anything but a full standalone, I'd never go back to some hacked up MAS.

sleepydsm · 01-02-2006

What about the Haltech?

**Shane@DBPerformance** · 01-02-2006

Quote:

Originally Posted by Goat Blower

Everyone uses speed density with the VPC, how can you max out airflow metering?

The MAP sensor maxes out. The VPC also does a trick to try to avoid hitting fuel cut that can make it cap the airflow that it reports.

**1ViciousGSX** · 01-02-2006

I hope DSMLink gets speed density, they are working on it.

**Goat Blower** · 01-02-2006

Quote:

Originally Posted by ecoli

The MAP sensor maxes out. The VPC also does a trick to try to avoid hitting fuel cut that can make it cap the airflow that it reports.

At 29.4 psi, although I've run 30-31 psi with no problems with it. I think Leon Reitman adapted a 5-bar map sensor to one back in the day, or somebody did. I don't remember anything about it capping airflow readings, although everybody is using much larger turbos than they were when everyone had a VPC. For $300-400, it's hard to beat for easy tuneability and getting rid of the stupid 1G MAS.

PSI2HI · 01-02-2006

I used a VPC on my 93 after my 2G MAS was tapped out. My car ran flawless, perfect idle, perfect driveability, made 530whp on 27 psi on a SCM61. I'll agree a VPC is a hard unit to beat for the price. You hear a lot of people talking how the cant get the cars running right or idling but i've personally used VPC on 3 1G's w/o any problems.