Single hole vs 4 hole fuel injectors

[DV8OR]

For the M70 motor can anyone comment on what difference the single hole vs. the 4 hole fuel injector will do in the M70?

[shogun]

Did you ever change the fuel injectors to 4-hole? Any improvement? Interesting subject.

There is presently a *bay company offering for the M70 Bosch single hole and a bit more expensive the 4-hole style (what they call upgrade). My opinion is that does not mean they inject more, what goes thru one hole, goes with same volume thru 4 holes, the pintle inside the valve decides what goes thru, that is why they also mention the same reference part number from Bosch for both *bay offers, copied: 1. 0280150715 , 2. Interchange Part Number: 0280150715, capacity charts http://users.erols.com/srweiss/tableifc.htm


Next point is that we cannot beat with our normal aspirated engines this 15:1 ratio: The stoichiometric mixture for a gasoline engine is the ideal ratio of air to fuel that burns all fuel with no excess air. i.e. for every one gram of fuel, 15 grams of air are required..

Then......people which like 4 hole injectors argue, the spray pattern is better. But..........does it matter for the old style M70 intake system? The spray pattern is different, but that is a different matter of discussion, does that really help on the M70?
Here they mention: In many production engine applications, injector spray patterns play a minimal role in combustion performance because the spray is usually not aimed at the intake valve. Instead, the spray is aimed at the intake runner wall or floor. This is done for many reasons such as for emissions or packaging constraints. In these cases, atomization occurs after the airflow picks-up the fuel either in flight or as it splashes off the runner. In performance applications where emissions are not an issue, injector aiming should be optimized towards the valve and atomization techniques should be utilized. Figure 3 shows various spray patterns of the Bosch injector with different types of metering orifices. http://performancefuelsystems.com/In...TechCorner.htm

Injector spray patterns http://www.witchhunter.com/spraypattern1.php

Fuel Injector Tech Corner, good reading stuff http://performancefuelsystems.com/tech.htm

comment from the E31 forum : The spray pattern will make a difference in a modern combustion chamber but in our old engines with low CR, the difference will be unnoticable.

Comments welcome

[shogun]

and up with this old thread. Anyone meanwhile tested 4 hole fuel injectors on his M70? Any differences, improvements?