mixture adjustment via head temp resistance Options

[ape914]

Just wondering if anyone has made up some data points on how a change of resistance in the head temp circuit effects the mixture?

I know of some one long ago that had installed an additional head temp resistor in line. They wired a variable resistor (potentiometer) all the way up to the dash so they could add enrichment on the fly. They had no airfuel meter so it was all seat of the pants.

I am considering that a a possible fine tunning method on a D-jet 914. With an aftermarket cam, big bore pistons and non-stock compression ratio, I think there might be some room to add enrichment across the range.

what I am thinking is to add an airfuel ratio meter, or go by head or exhaust temp as a guide, and adjust the mixture via this method and watch the gauges to try to find an optimal setting.

Has anyone already tried this?

How does head temp reistance effect the mixture? is it uniform across the rpm and load range? or does it only effect certain running conditions?

Just begining the thought process on this, and dont want to re-invent the wheel if it has already been tried.

By running a parallel reisistance, one could also lean out the mixture.


I know some folks will tune the Pressure sensor (MPS) to change mixture, but I am thinking this is one more tunning tool maybe,and with a variable resistor wired to the dash, it can be changed on the fly, unlike MPS adjustments.

[brant]

cool then you cam sounds like you don't have a problem.

you really need a wide-band sensor

I've tuned a couple of MPS' with my innovate
its easy...

you prep the MPS by taking the puddy out
you find an open bit of highway
you do WOT throttle runs to 60 or even 70mph
you pull over... adjust... do another run

then you tune the same way for cruising

its really easy to do
but without the wide band you are only able to guess by the seat of the pants

a wide band will tell you exactly what is really going on.

[ape914]

cool then you cam sounds like you don't have a problem.

you really need a wide-band sensor

I've tuned a couple of MPS' with my innovate
its easy...

you prep the MPS by taking the puddy out
you find an open bit of highway
you do WOT throttle runs to 60 or even 70mph
you pull over... adjust... do another run

then you tune the same way for cruising

its really easy to do
but without the wide band you are only able to guess by the seat of the pants

a wide band will tell you exactly what is really going on.

yes a Air / fuel meter is probably the way to go (more money!!!)

Have you any experience in tunning via a head temp or exhaust temp reading? i know that exhaust temps have been used for tuning, probably before Air / fuel meters became popular.