boost mods

Ben Swann bswann at
Tue Aug 6 23:39:50 EDT 2002

Taka does have a good point.  There is the limit to the CIS, which is why I
added an injector and should be sufficient.

I have made trial and error runs which confirms the limits to be in the
18-20 PSI on a good cool day, and a safe setting for all operational
conditions to be around 15 PSI.

This does however indicate that water injection may do quite well.  I have
read the same, in fact a statement to the effect that adding water properly
can be even more effective than fuel.  Forget where offhand though.

I'd sure be interested to know of some results of adding a sytem in one of
these cars.


On Tuesday, August 06, 2002 7:06 PM, TM [SMTP:t44tq at] wrote:
> I don't think the fuel system can provide enough fuel for
> 1.2 over atmospheric (that's about 18psi, right?).
> With EFI, you won't need any extra injectors- you'll have plenty
> unless you try to run something crazy, like 24psi, then you'll
> need direct ignition.
> Taka
> -----Original Message-----
> From: quattro-admin at [mailto:quattro-admin at] On
> Behalf Of Ben Swann
> Sent: Tuesday, August 06, 2002 9:35 AM
> To: 'tonytuzz at'
> Cc: 'quattro at'
> Subject: boost mods
> [Answering your questions:
> 1.  I'm no sure how I'm going to do 2.2 bar yet.  Scott Mockry was
> thinking about doing a chip, but I don't think he ever got around to it.
> Nobody does a pure electronic solution that I know of (i.e., chip and
> transducer, which probably isn't feasible anyway), so I'll either do the
> resistor fakey/big spring(resistor changes the resistance the computer
> sees, making it think the boost is lower than it is), big
> spring/schrapnel knob (device that reduces the air pressure the computer
> sees), or a combo of all three.  What I'm waiting for BEFORE I go to 2.2
> bar is H20 injection.  Car pings a bit on 91 octane now at 1.8-1.9 bar,
> imagine what it will be like at 2.2 bar.  I'm thinking grenade.]
> I have been using combined resistor and QLCC chip & shrapknob for some
> time and it works fine when dialed in properly - I have set for about 15
> PSIg and no pinging with 93 octane on even the hottest days.  I'll get
> even more once I hook up the extra injector and 034EFI - someday.
> Ben

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