[DML] Re: PRV Performance - Set me straight please

["endotex23" <endotex23@xxxxxxxxx>]

--- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@xxxx>
wrote:

> Series 066 full throttle enrichment is only active below 125 degrees
F (via a thermal vacuum cutoff) and even then is only active for ~10
seconds (via an equalizing delay valve). DeLorean lowers thermal
cutoff to 104 degrees F.<


While several other models of CPR do have it the 066 has no full
throttle enrichment feature. WOT enrichment on the Delorean is
performed by a throttle mounted switch and done electronically by the
Lambda controller. What you're refering to is the 066 acceleration
enrichment, which is something else all together. If it was true full
throttle enrichment it wouldn't be a 10 secound function. It's only
used for cold acceleration under partial throttle and (as you pointed
out) is not active once coolant temperature warms up. 

While we're on the subject owners should know accel enrichment via CPR
was replaced on 1982 and later B28 applications (outside the Delorean)
by using a differential pressure switch to electronically provide
acell enrichment through the Lambda system. This results in improved
response during cold acceleration and relegates the 066 CPR to warm up
enrichment only. This modification can easily be retrofitted to
Deloreans by employing the Volvo switch and an unused input on the
Lambda controller.

To the fellow who wants to remove his Lambda: I'm guessing you don't
really understand it's function or you wouldn't be in such a hurry to
yank it off. However, if you remove it you must also remove the
catalytic converter because you'll render it useless in short order
(or overheat it). And you should leave the Lambda loop active even if
you remove the converter.

Disabling Lambda removes closed loop mixture control. It's better to
leave it for several reasons assocciated with that problem, not the
least of which is emissions. If you want to remove it to gain power
(because of it holding your mixture at stoichiometric) there are ways
to "program" the Lambda controller to deliver any A/F mixture you'd
like within reason. For example you could have best emissions or best
power at the flip of a switch. 

In either case it'd still be operating in closed loop and that beats
leaving mixture control solely in the hands of the basic K Jet. The
fact is closed loop control beats open loop any day of the week for
drivability, emissions, and fuel economy and removing it will usually
get you less performance, not more. I suggest you have access to a
decent exhaust gas anyalzer if you do decide to pull it off, you're
going to need one to get things right. And without closed loop the
mixture (and hence performance) will wander based on numerous
variables. You can also pretty much forget about passing any emissions
test worthy of the name.

Greg








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