Autosport Labs

i am building a megajolt lite jr to run on a 2ltr pinto with many mods and twin 40 delortoes these carbs have both tps and four vacuum take offs that i can use
which is the better system tps or linking all four vacuums together and conecting this to the megajolt map sensor
thanks dave

Opinions vary, but I believe using the MAP sensor is a more accurate measurement of engine load. Unless... you have wild cams, in which case TPS would be better for you.

Brent

hello brent i will be using a 285 kent cam so at what point does a cam become a wild one
is it the large overlap that causes the problems for a map sensor
ps the board looks great cant wait to use it
cheers dave

Ok, MAP sensors have problems with both lumpy cams and intakes that flow alot of air. A set of individual throttle bodies will be pain for a MAP sensor. A stock vehicle that emits a healty amount of vaccume would work great. Not a 1500cc Honda motor with 288 duration cams and Weber DCOE 45's.

A TPS makes more sense to me, it wont take in effect of atomosphereic changes and what not, but that's why you have a programmible ignition right?

How "wild" a cam is depends a great deal on the capacity and compression ratio of the engine.
From my Mini years, a cam that was mild in a 1400, placed in an 850 would result in an engine that idled roughly and wouldn't pull till it hit 4000rpm.
There was a point at which when matching a distributor, we'd go with purely manual advance and dump the vacuum, but it's going to depend on the cam. We had vacuum with a 266, non-vacuum with a 276/286.
Have a word with whoever supplied the cam as to which distributor they'd recommend for that overlap, and base the decision on MAP or TPS on that:-
This from the Aldon site

FORD OHC (PINTO) ALL BOSCH UNITS
104FPY
A non-vacuum distributor to suit engines fitted with side draught carburettors but retaining the standard camshaft.
104FPR1
A non-vacuum distributor to suit engines fitted with side draught carburettors and fitted with a modified camshaft such as piper 270, 285, Kent RL1, RL2, Burton 32, 33 or 40, 41 etc.
104FPR2
A distributor with vacuum advance to suit engines fitted with twin choke
down draught carburettors together with a modified camshaft.

Any help?

On my 2l Pinto with twin Dellorto 45s installation, I have used tps. It works well and was simple to implement. I haven't come across anybody using MAP with Weber or Dellorto carbs. If there is it would be good to hear their comments.