· Just Some Dude in Jersey
I was thinking of doing this to a manifold:
My comment wasn’t clear. If you were to look at a round runner head on I don’t think it would matter what degree of the circle the injector fires from.The bump might be there to add turbulence near the injector to improve air/fuel mixing or to push the airflow towards the offset injector to improve air/fuel mixing.
The injector offset may be to better aim the spray of fuel in the direction that the air flows through head. The ports in the head aren't a straight shot to the valve/cylinder, they each bend right or left towards the valve.
If this was the case, I am hoping that the modern fuel injectors and higher pump pressure provide better atomization.The bump might be there to add turbulence near the injector to improve air/fuel mixing or to push the airflow towards the offset injector to improve air/fuel mixing.
What is interesting is that the humps were in the middle (the divider between runners of each arm) so they are not consistently on one side or the other for a given armThe injector offset may be to better aim the spray of fuel in the direction that the air flows through head. The ports in the head aren't a straight shot to the valve/cylinder,
no matter the option, I figure I need to get the injector bungs all machined at the same 30 degree angle from parallel. I checked my metal bandsaw And the limit of cutting is about 52 degrees. So I designed and am 3D printing a jig to get the extra 8 degrees. So 60 degree cut from a right angle should be 30 off of parallelSo, here are the options that I am considering to proceed:
- Machine hole for injector bungs from opposite direction (from the inside from the head flange).
- Drill and weld the bungs into a piece of aluminum similar to original design but welded
- Machine slots from top using a small hand tool
- Cut off some of the angle / length of the runners and weld back together
- Cast plenum of modified design with shorter, less angled arms.
Thank you. Could you perchance measure the diameter of the throttle body that you tried? It might be just what I am looking for, as I am going to put a flexible / programmable stand alone ECU and have started gather parts to upgrade displacement to 2.4 liter stoker.Keep in mind that the oem FI was solely focussed on economy and low emissions, with very little consideration of power. When I was configuring the 2.4 motronic FI on my 2.4, we tried out an aftermarket throttle body that was the equivalent size to the larger throttle on a 6 cylinder 3.0 liter Opel FI system. The 2.4 computer was too dumb to handle the much larger air flow, but at about mid-throttle it had rev response that was super fast, like you are trying to achieve. With a more adaptable computer, that could deal with the higher air flow, we could have made it work and gotten a faster rev'ing engine.
So, what I'm saying is: Don't get locked into the stock throttle size. I don't know how one calculates the maximum size throttle that an engine can handle, but going big on the throttle is something to consider. I'm sure there are detriments to going too big or too small.
Thank you for the driver insight and technical perspective. I am definitely looking for a driving experience that makes me smile (not annoyed). So I’ll rule out the 70 mm.Just an FYI, but a 60 mm TB can easily handle 200 hp.
If you go too big on the TB, you end up with a sort of ‘on-off’ throttle response. It can be annoying on smaller displacements.
I think that @krewzer must have modified the manifold for the cowling before sending it to me. Here is a picture of the originalHow is your clearance between the manifold and the cowling?