I have a couple of questions on acceleration enrichment injector pulse width times:

1.) When you add bigger injectors and leave the acceleration enrichment injector pulse width times the same, you obviously dump in much more fuel when you press the peddle down. Are the factory AE times a little lean, so that increasing injector size will actually be beneficial under acceleration (assuming the VE tables are right). The reason I ask is I put 65% bigger injectors on my TBI car, re-tuned the VE tables, left the AE stuff alone, and she's way more responsive than before ...could be my mind

2.) I'm seriously considering removing the dividing wall in my dual plane manifold to give me more plenum volume and a better top end. This shouldn't hurt bottom end torque or responsiveness on a TBI vehicle, but I've heard that it would require a big increase in AE numbers. I know some of you are using single plane manifolds on TBIs. How much did you have to change the AE numbers? Does it make sense to say that because plenum volume has practically doubled, then the AE injector times should be almost doubled as well? ...just looking for a starting point.

 

I found going from a Performer RPM (dual plane) to an original Torker (single plane) required less AE. Seems correct as there is much less wall area in the single plane.

I don't think you will see much difference in AE requirements by just cutting part of the divider out. But you never know until you try it.

RBob.

 

I found going from a Performer RPM (dual plane) to an original Torker (single plane) required less AE. Seems correct as there is much less wall area in the single plane.

I don't think you will see much difference in AE requirements by just cutting part of the divider out. But you never know until you try it.

RBob.

 

Transients are the toughest to tune. Alot of people add timing to help with the transients and it will definately aid you in the tuning...but taking timing away and then working the transients will teach you alot more.

 

on the dual plane you had half as much plenum. which flowed air at a higher velocity. in a single plane you had a larger plenum with a lower velocity. but oddly enough the real thing to think about is mixture distrobution. in a single plain you have a much larger premix area then you do in a dual plane. with the higher level of turbulence in the cavitation zone under the carberator youve created more tumble for mxiture. this would require far less AE. also you have a much shorter distance to travel so the fuel wont fall out of suspension as easily.again requiring far less AE.

 

The best manifold I ever used on a TBI with moderate gearing, was the Wieand 7525. While it didn't have the off idle torque of some of the others, at 2,000 and above it was alot more fun to drive, then any dual plane.

A dual plane has 4 pairs of different runners, that just so happen to work best at different times, whereas with a single, ocassionally both sets of runners work in unisone.

FWIW, back in the mid 90s I tried every SBC dual plane available, and then started trying singles, the low profile Wieands were pretty good, then the 7525, I never tried any of the other singles, since I was so happy with the 7525.

Single plane, vs dual is just about as much driver's preference, as moving the torque range around.

Yes, one would think going to a bigger injector would mean cutting back the AE, but, the engine isn't always on the same page as humans, that's why I stick to just *giving it what it wants*. BTW, the bigger injectors do alot towards keeping an engine out of tip-in pre-ignition.