Thread: computer engine manager for V8 RR

Various aftermarket ECU's will do sequential injection but it will be a wasted expense if you are converting to lpg as you will use lpg mostly.

Originally Posted by loanrangie

Various aftermarket ECU's will do sequential injection but it will be a wasted expense if you are converting to lpg as you will use lpg mostly.

Ah yes, but....

The LPG system ties into the car computer. I suspect the LPG injectors will also fire bank-bank rather than sequential. Another advantage of an aftermarket system is that one can dual-map the ignition system to get more advancve for LPG. I plan to get a Haltech Interceptor added to my P38A for dual-mapping of ignition and also to remap the petrol.

My old '87 Rangie had an early Haltech system that could be set up to run as sequential - it replaced the Lucas system. It had the advantage of not using the Lucas flapper which was removed and replaced by a straight bit of pipe with a MAP sensor.

I wonder if one of the reasons the P38A gets better fuel economy than a classic is due to the sequential injection.

Everything that I have read about sequential injection states that the major benefit is in emissions at LOW revs.
There is a long discussion on the Megasquirt site AFAIR.
The main issue is that injectors take a finite time to open and close and that effectively the injector can only squirt into an open inlet valve at low revs and load. The valve opening events take place so fast at higher revs/loads that there is effectively no difference over say 1500RPM and (my estimate) 10% load. This is because a sequential system is squirting on closed valves anyway .
I suggest that economy in later V8s may be partly due to sequential but FAR more due to vastly enhanced ignition control holding the timing just short of detonation at all revs/loads by utilising 2 knock sensors and very detailed timing maps.
The Thor 38As also run 14.7 at all loads which helps economy vs rich WOT. This is only possible with very efficient and fast knock control. The Motronic also reads the resistance of each spark plug firing and balances the injectors cylinder to cylinder based on the feedback.
Regards Philip A

hmmm
anyone up to teach a class on Fuel injection for newbies?

bank bank?
I assumed injectors fired as per spark sequence,,,

????