Re: Callaway Turbo Kit

[Linus Toy <linust@mindspring.com>]

At 12:02 PM 2/3/98 -0800, Gary G. Erickson wrote:

>OK, but you _did_ say that there is a knock sensor involved, and as I
>recall, moving to the LH-Jetronic means pulsed fuel delivery rather than
>CIS, which (Disclaimer!!) I've been _told_ is better suited to fueling a
>forced induction engine.

yes, the B230FT has a knock sensor ignition, but it is an isolated
system--that is, it does not interract with the FI system--in fact, I
believe you can detach it from the engine without touching the FI or main
engine electrical harness.  IOW, for the mid-80s Audi 4kcsq/Coupe GT, you
could add a simple knock sensor ignition--either aftermarket or possibly
the system used on the late '87 Coupe/'88-on 80/90q (NG engine?) and
accomplish similar results (ignition only--turbo & plumbing another story).  
As for the LH-Jet vs. K-Jet and which is better, I can't add anything there.  

>And you could expand on this system a bit (or introduce it to a
>home-brew) by incorporating the APC system that Saab used in their
>mid-80's turbos (this system was discussed on the Q-list back in
>October; more info can be found at
>http://www.teleport.com/~bertram/volvoapc/ )  This system utilized a
>knock sensor and WG freq valve to monitor for detonation and pulls the
>boost down if pinging is detected.

the concept behind the Saab APC controller is what Scott J. (QSHIPQ) talked
about in his post on wastegate cracking (date unknown).    This is the same
thing you'll spend a few hundred dollars on for a Trust or Greddy boost
controller--most of the folks adapting the APC to a Volvo seem to do it for
< $100.  I'm not sure how much of this would be adaptable to the Audi MC
engine since the computer already does a certain amount of wastegate
control.  btw, John Bertram, the guy who adapted the Saab APC to his Volvo
is a Saab technician (but a Volvo enthusiast).  

>But considering the amount of R&D and potentially costly testing work,
>why would you want to?  There's an awful lot of custom plumbing
>involved, and I think the effort involved would pretty quickly overrun
>whatever it would take to install a full MC engine and computer.

absolutely--it is a lot of work, yes, the "factory" way is easier.  but
given the abilities of people on this list and some of the ideas we
initially thought were hare-brained (and later turned out to be
doable--remember converting a FWD 4000 to a quattro?) some people simply
want something different.  Feasibility?  we already know of one K-Jet to
EFI conversion on this list; as you note, there's 

>We know somebody whose done it, but even he's admitted that it has it's
>problems.  The big one being the control of detonation under boost
>conditions.

yes;  I think many of his issues are related to relying on a pop-off valve
for boost control--instead of a wastegate.  remember--he went this route
because a wastegate in the 4k body means using the $$$ ur-q RH tie-rod.
that project DID use a turbo engine as a base, btw--just not the full Audi
engine management system and wastegate.

my point in comparing the Volvo B230FT was that I don't see major
fundamental differences between the Volvo turbo and an Audi NA --> turbo
conversion (based on similar CR) -- afterall,  Callaway figured out a way
to turbo the Audi I5 NA engine--they just couldn't figure out how to make
money on it and keep it affordable.  

like you, i probably wouldn't do it this way--except my dream wouldn't be
an MC conversion, but a 3B conversion :) ... but for bench-racing purposes,
its an interesting exercise!
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* linus toy                       email:  linust@mindspring.com      *
* mercer island, wa                                                  *
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