MSefi.com read only forum (Jan.15,2018)

Does anyone sell plugs to fill injector holes? I am moving my injectors from the GSX-R throttle bodies to the intake manifold so they are situated directly behind the intake valves. I will need to fill the holes left by the injectors that used to be in the throttle bodies. I seem to recall seeing injector plugs to fill the holes, but I wasn't able to find it with google or the forum search tool. Does anyone know where I can find them? Otherwise I'll need to have something machined.

Thanks,
Robert

Hi Robert,

All the conversions I've seen on GSXR throttle bodies have used liquid metal to fill the holes. It may sound a bit heath robinson, but it seems to work as it forms a proper bond to the existing metal and a lot less labour intensive than having interference fit plugs machined.

Just a thought! ;o)

Cheers

Darren

You could drill and tap them for an 1/2-14 NPT plug, if they are smaller than .7188 now. You can also buy ground aluminum bar stock through Mc Master Carr that might "hammer" in.

I'm curious, is there any particular reason you are putting the injectors right behind the valve instead of right after the throttle plate? I ask because I have a set of Hayabusa TBs I eventually plan to put on, and I was planning to move the injectors from behind the valves to the throttle bodies. I was thinking fuel atomization would be better with the injectors farther from the head. But I'm really curious what others think.

C|

Folklore has it that emissions and low load operation are greatly facilitated via at-the-valve injection and vaporization, high power needs are supposedly better addressed via remote injection for the reasons you spoke of. One observation is that F1 engines have injectors in front of the throttle plates, I do not know if they have them at the ports for low load operation. F1 is probably not a good example for the operating regimes most of us common folk deal with, the F1 engines idle at 5K and typically use 19K (19000) rpm as their shift point. My personal application has the main injectors 17" from the ports located immediately after the plates and secondary injectors in front of the TBs. This was not an attempt to emulate F1, I simply don't have any other available physical locations for the injectors for my engine due to turbo placement, heat considerations, etc. It works well after a little fiddling with AE, etc., but would probably be difficult to get a good cold AE result on if I were in an actual cold climate due to intake manifold wall wetting. As it is, during warmup I can get little patches of water condensation ice on the exterior of the manifold where the primary injector spray pattern contacts the wall at a 90 in the manifold. That fuel does get cold when evaporating in a low pressure, low flow environment!

-Mike