[DML] Re: DeLorean vs Volvo F Series Question.

["Bruce Benson" <delornut@xxxxxxx>]

Even though the two used basically the same engine there are differences in 
the physical characteristics of the cars. Things like rolling resistance, 
weight, how the car deals with driven air flow resistance along with 
differences in gear ratios means that the emissions produced can be 
different. I'd guess the ignition changes were made to adjust for those 
differences. I did try a Volvo distributor in my DeLorean on one trip from 
Minnesota to Texas. The engine felt like it had slightly more torque and 
pulled better at low RPM's  but the DeLorean ignition seemed to allow the 
engine to rev more freely and the car just felt a little quicker. Overall I 
liked the feel of the DeLorean ignition setup over the Volvo. I'd guess 
Volvo runs 10 degrees advance to adjust for emissions. I'm running 18 
degrees advance in my DeLorean and the engine feels good. The recommended 13 
degrees is for max emission reduction. I think 10 degrees would produce a 
somewhat noticeable reduction in power.

Bruce Benson


> 1a. DeLorean vs Volvo F Series Question
>    Posted by: "content22207" brobertson@xxxxxxxxxxxx content22207
>    Date: Tue Feb 5, 2008 7:34 am ((PST))
>
> I am corresponding with an owner Re: spark advance. As we all know,
> DMC decided to use only one centrifugal counterweight inside its
> distributors rather than two (Volvo used two on its imports to the
> exact same North American market). To compensate, DMC:
> - Bumped base ignition time from 10 to 13 degrees BTDC
> - Ran full manifold vacuum rather than ported vacuum to the advance
> diaphragm
>
> This oOf course leads to generally overadvanced ignition, so for
> better starting and cold engine performance DMC further:
> - Ran its vacuum through a thermactor valve and an idle cutoff
> solenoid before the distributor
>
> My question: Why did DMC find it necessary to reinvent the spark
> advance wheel?
>
> B28F has two centrifugal counterweights, 10 degree base ignition time
> (steeper advance curve), and only one vacuum line from a ported barb
> under the throttle plates directly to the advance diaphragm. What
> could be simpler?
>
> And again: Volvo imported its setup into the exact same North American
> markets, during the exact same time period (1981-1983). If their setup
> was good enough for the US government, shouldn't DMC have been able to
> use it too?
>
> BTW: US Volvos also came with a Y pipe and single catalytic converter.
> They used Lambda as well.
>
> More engineering from Dunmurry that causes me to scratch my head.
>
> Bill Robertson
> #5939
> 


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