Is the Buggy B9 shimmed for 30%? should i take a shim out after breakin? thanks

NO Don't pull any shims on a B9 (C6), RB recommends adding a .1 shim for 30%. Some people will say it will be fine to run 30% with stock shimming but do you really want to risk blowing up a $400 to $500 engine.

no extra shims in box hmm. i guess i'll order one to be sure unless Chris Peralta has some exp. with the shims in the B9 I think hw runs one. i'll wait to see how his is running and if he added a shim or not thanks.

Yeah I am cool with Jersey he know me. He be talking about bumps and jumps. I just didnt want to take the 2 hour ride up there. When I am at Hobbyhut I am with B Webb. I have to get the RB 2045 pipe than I will start running some tanks through that Killer 9. I am thinking of a RB motor to get for the buggy. I am not sure yet though. Any ideas?

Pick up another Killer 9 for your buggy, this engine is a high end screamer. The engine will probably perform quite well in a buggy. Try a JP1, heard it is pretty good for this engine as well. I know who you are, I just don't hang down that side of the track.

Hey man, the engines are technically shimmed for 25% nitro but this is assuming you are at sea level. If you are right at sea level it is probably a good idea to get the extra shim and run it with that extra shim for the first gallon of fuel. If you are above sea level at all 1,500 or more feet you can go ahead and run the 30% with the shimming that is stock in the engine.

I can tell you that I have personally run 30% in my engines at sea level before but you could be taking a chance. When doing this I try to only run #6 plugs to help keep the engine from pre detonationg. Basically when you go with a hotter plug it's going to cause the fuel to burn just a tad bit sooner, the same goes for removing headshims to a point. This is where you have to be careful because if the fuel is firing to soon in the chamber this is Pre-Detonation and will cause tiny little pit marks on the top of your piston.

So the best place to start is, whats your elevation where you race?

i think im pretty much at sea level i am in delaware flat as a pancake by the ocean. the highest point in the state of delaware is the land fill man made hill of crap lol!

I doupt the C6 is shimmed perfect from factory..I know on my C6 i removed s shim or two to run 30%...adding shims usually makes an engine run worse, not better.... I need to measure the C6 compression again, but i will be money its over shimmed from factory and the stock compression is pretty low

When I got my B9 it recommended adding .1mm shim to run 30% so I did it and it runs very good. I never shimmed and of my C6's and they ran good and all are getting or got 8 plus gallons, so I just don't know. RB sells a .1mm shim kit with 5 shims in it.

shew 11 for shims + $4 shipping i guess i better get a bigger order so im not paying all that shipping for nothing. LOL

my C6 is a few years old now, so maybe the new ones have changed....but on my own C6 and several others I did we did remove a shim and ran 30%..... motors run strong with no issues.....

They come with 1 .20mm shim and 1 .10mm shim I personally run 30% nitro with the .10 head shim removed, as well as a number 5 plug. This runs great for me at my elevation here in Colorado and does not pre-detonate. I tried to run my engine like that in Phoenix with 30% and I had to actually put the shim back in as it did start to pit the top of the piston a little.

Removing head shims does make the engine run better for the most part, but you just have to be careful. Make sure you pull the glow plug out after running to look at the top of the piston. If you have no small pits you are just fine.

Here is a pic of my piston after 3/4 of a gallon. they may be some light pitting not sure?






looks like two shims total from factory.

To me it does not look like any pit marks. If it's got the pit marks I am talking about you can actually feel them, plus if you have almost a gallon on it with the stock shims and 30% it would be very marked up after that much fuel if you did need the shim. The engine should be loosening up for ya right about now and you should start to notice it runs better and better every week.

Also, I see in your pic that you don't have fuel tubing over your exhaust springs. Cut some fuel tubing and put it over the springs holding the header to the engine and you will never loose a spring from rattling off.

Aaron,

Did you get a chance to run your K9 with taking out that shim? If so, how did it run.

Allen