93 head port & polish progress pics (56k a little slow)
#61
My one thought on all that:
Since air only flows to one cylinder at a time, how much does it matter if flow isn't evenly distributed when all the runners are open? The air only has one place to go at a time, so it will go there, right? It may not be exactly perfect distribution, but can't be that far off, I would think.
Since air only flows to one cylinder at a time, how much does it matter if flow isn't evenly distributed when all the runners are open? The air only has one place to go at a time, so it will go there, right? It may not be exactly perfect distribution, but can't be that far off, I would think.
#62
I would think slight differences in port filling would be a big factor. You'll have all the ports running different percentages of lean/rich, since you only have one maf sensor and one O2.
The whole point of flow-matching your injectors goes out the window with improper porting. What I did to my LIM should have no effect on this because I left my heads alone, and simply portmatched my LIM to them.
The whole point of flow-matching your injectors goes out the window with improper porting. What I did to my LIM should have no effect on this because I left my heads alone, and simply portmatched my LIM to them.
#63
My point (rather, question) was: can they be different enough to matter since the intake is pressurized and air only goes to one place at a time...
Have you (ssei1995) checked flow one runner at a time with the others blocked? If so, disregard what I said.
Have you (ssei1995) checked flow one runner at a time with the others blocked? If so, disregard what I said.
#64
Since air only flows to one cylinder at a time, how much does it matter if flow isn't evenly distributed when all the runners are open? The air only has one place to go at a time, so it will go there, right? It may not be exactly perfect distribution, but can't be that far off, I would think.
It does matter. Evenly distributed airflow in the intake reduces reversion duirng the exhaust pulse. This is a problem with blown engines and worst when the camshaft has a lot of overlap. That is the reason why when you remove the SC and look at the bottom of the intake, you will notice a lot of soot, or what you guys call carbon deposits. The intake is pressurised most of the times underboost, therefore, all you are doing is improving the filling of the cylinders and atomization. I can write a whole thesis on the subject based on findings and other people'* results and observattions. If you take a close look, the SC opening does not cover the whole length of the intake opening. Also, the intake opening does not expose all the runners either.
You can easily get lost on the subject if you also add the issue of engine builders changing the firing order of the cam to dampen the pulses in the intake tract.
I would think slight differences in port filling would be a big factor. You'll have all the ports running different percentages of lean/rich, since you only have one maf sensor and one O2.
#65
Have you (ssei1995) checked flow one runner at a time with the others blocked? If so, disregard what I said.
#67
ssei1995, you certainly have my undivided attention, and apparently that of many others as well. Please keep us posted. Also, I am sure if you need any type of assistance, all you need to do is ask. Many of us are eagerly awaiting the results of your research.
#68
Related followup on mine:
I'm glad I didn't touch my heads for the time being. I believe in the long-term the port-matched lower intake should help, and I know the ported EM'* are a benefit. However, it appears the ported TB is too much with even the modified curves in my Jet PCM. I'll have to take data, then switch back to a stock TB and see how it acts. Even without the ported TB, I should be at least 30hp stronger in the top end of the motor alone.
More testing and scanning to come.
I'm glad I didn't touch my heads for the time being. I believe in the long-term the port-matched lower intake should help, and I know the ported EM'* are a benefit. However, it appears the ported TB is too much with even the modified curves in my Jet PCM. I'll have to take data, then switch back to a stock TB and see how it acts. Even without the ported TB, I should be at least 30hp stronger in the top end of the motor alone.
More testing and scanning to come.
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