I’m having a hell of a time with trying to set up the radium secondary rail on the Xcessive LIM. I bought a used LIM that came with FFE reducers to work with 14mm o-rings, when putting the rail on the injectors were too high and interfered with bolting the rail down tight on the 11mm spacers it specs to use for the Xcessive LIM. I removed the FFE reducers and the injectors seemed like they would fit but now I don’t have larger o-rings to make it work.

per the Radium instructions you are not supposed to use reducers/seats with the Xcessive LIM, it does not however spec o-rings to use.

I found these 16mm/denso adapters but I don’t want to buy without knowing they will work. https://www.t1racedevelopment.com/pr...denso-cushion/

Have any of you encountered this problem and how did you get over it?

I will call Radium tomorrow to see if they have a solution, in the meantime I hope I’m not the first to come across this!

 

I bought my ID injectors using the part numbers from radius’s instructions.

 

Did your LIM come with the black injector seats?

 

Well, I think I may have figured this out on my own, or I just ordered lower inserts I don’t need. I’ll report back on that later, in the mean time here’s what led me to action.

After doing some more looking around about the “Denso cushions” I found an old thread HERE, started by the one and only @arghx that encouraged me take a second look at the injector inserts/seats I had on hand. Since I pulled out my old fuel system I had some FFE blue lower o-ring inserts to compare to the black
ones I pulled out of the Xcessive lower. The blue ones are shorter and have an extra shoulder on the bottom. Per the FFE instructions you remove the plastic step/seat on the ID injector and swap the 14mm o ring out for two 11mm o rings which allows the injectors to sit low in the inserts.

That appears to be a simple solution for my injectors. Since I plan to run some
dummies for the inner injector ports I had to look at those as well. They are what I originally test fit with and probably caused me to go down a greater rabbit hole than I needed to because I have an inclination that the ID injectors would have just barely fit the black inserts. The dummies have a shorter shoulder above the o-rings than the injectors do. The shorter shoulder interfered with the black inserts and caused the rail to sit too high. I believe that even with the blue inserts these shoulders will be too short so I’m going to have the dummies machined for more clearance.

tl;dr- the black inserts may have worked with the injectors only but since they interfered with the dummies I took all of them out and sought another solution landing on blue inserts from FFE and plan to machine the dummies a little bit to shorten the shoulder.

Pics for context:

 

Are you missing the caps that come with the Excessive LIM to close off the extra injector bungs. The Radium rail comes with plugs for the extra injectors if not used.

 

Yes, I don't have the caps as I bought this LIM lightly used. I have the Radium port plugs but I want to be able to close off the manifold injector port with a injector dummy instead of a plug, the reason being that if I want to add injectors in the future I can just pull out the dummies and rail port plugs and run additional injectors without removing the LIM.

 

on my Xcessive and Elite LIMs I just tapped the 2 middle ports for 1/4 npt plugs. The thread is on the ID of the lower hole and does not damage the sealing area at all so no problems if adding extra injectors later.

 

I remember seeing that in the past. It will be a last resort for me at this point. I’ve dropped the injectors and dummies off with a machinist and he’s going to copy the injector profile onto the dummies. I should be good to go now!

 

The dummies are machined to match the injectors. Hopefully the FFE order isn’t held up and I can get these going!
Original is on too, modified is on the bottom

 

glad my old threads are still helping people!

 

I have those same dummy injectors and had the exact same fitment problem.

I put them in my drill, turned it on high, and hit it with sandpaper. Problem solved.

 

Yeah. I haven't found any dummy injectors that fit right. They seem to all be slightly different than actual ID injectors. I think it's only an issue in the rx7 application where we are using the bungs which doesn't allow for any difference in profile.

 

Bringing closure to this, everything fits now. If I didn’t use the dummies the original black seats would have worked fine which is probably why everything fit right up for @Trout2 .

 

I'm using the Pro-Jay dummy injectors with the new version Xcessive LIM, Radium seats/sleeves, 11mm spacers and the blue hats for the injectors. No fitment issues. The seats fit in there pretty loose, but no leaks using a smoke machine.
I used the same Radium seats for the primary bores and the rear bore leaked like mad. I put slightly thicker O rings on the sleeves and so far, so good.