variable boost

[bangskl]

Hi Everyone;

I'm trying to find some information on a variable boost controler for the DS4 equiped 6.5 turbo engines. It was made from a variable resistor that was used to "fool" the ECM into allowing more boost to be built. I saw the article some time ago but didn't print it off. DUMB! Now I can't find it, even in the 6.5volumes that I bought.

I've got a 1994 6.5 turbo with a cold air intake and FSD cooler (so far). Upcoming mods will be mild; gauges, exhaust, bypass oil filter,etc. I'd like to be able to tweak the boost a little too. Can anyone help?

Thanks'
Ken

[More Power]

The adjustable boost pressure controller has been discussed many times here in this forum. Searching should turn up quite a few threads and posts. There's also an image showing the basic wiring diagram for the variable potentiometer in my photo album (which you have access to). :)

Jim

[bangskl]

Thanks for the leads.

Unfortunately your picture is the only thing that I was able to turn up. I get the schematic. What I couldn't see were what values you were using. The text ends after mentioning 5k should cut the signal in half.

Is my reasoning right in assuming that I would use a 0 - 5k variable resistor? 0 ohms being no alteration of signal (stock parameters) and 5k cutting signal in half meaning potentially double the boost?

I appreciate the help.
Ken

[More Power]

Is my reasoning right in assuming that I would use a 0 - 5k variable resistor? 0 ohms being no alteration of signal (stock parameters) and 5k cutting signal in half meaning potentially double the boost?


A 0-5K or 0-10K would probably work. The drawing shows how to connect the pot. There are finite limits to what the PCM will accept in terms of pot adjustment, what level of boost pressure the turbo is capable of and you'll need to consider the efficiency of the turbo.

We first published that idea in March of 2000. I haven't personally tested it, but others have, and a couple of vendors offer plug-n-play commercial versions (no cutting of the wires).

Jim

[RyanA]

Post the picture. If you are going across the wires, you don't want 0 ohms. If you are just cutting one wire and putting the pot in line, you would want 0 ohms. Going across the wires 0 ohms would be a dead short...

[Kennedy]

My best advice in this area is to do this with a chip. The 96" single sensor trucks worked very well with this mod, but the 94-5 are limited.

[a5150nut]

If you go with the variable pot trace your wires inside the dash and mount it near the puter away from the heat and moisture of the engine compartment. Had mine ther for 4 years now.