OFNA GT LX advice on shocks, diff oil, etc.
 

Some of you may know that I recently purchased an older/extremely clean Ultra GT LX from a co-worker some weeks ago (price drop to $80, :D). Well I finally got most of the necessary parts for it (front u-joints, bumper and filter) so I can at least run it instead of watching it idle. Next on my list is to replace the carb o-rings in both the HSN and LSN as the LSN keeps backing out on me causing a rich tune.

My questions are.......

1) What oil is recommended for the shocks? I bought 37.5 and it doesn't seem stiff enough for them as it bottoms out easily (especially the front), OR should I buy stiffer springs, or both?

2) What weight Diff oil is recommended for bashing? (I'll probably never attempt to race it)

3) What shocks from other models will fit on this?

I ask these questions because this car handles totally different than my Backdraft. It's ALOT more unstable when encountering bumps and small jumps, even bottoming out on several occasions where the Backdraft won't. I realize that the Backdraft is a newer design but I figured the OFNA would still be able to handle everything the Backdraft can due to the better parts and design. I really need to try and stabilize this car if it's possible because it has a .21 Picco 0-1 Boost engine which is SO much faster than the .21 SH in my Backdraft.

Thanks in advance for any input and suggestions!

guff you can use heavier shock oil in front say 55 wt and 45 wt in rear as temperature changes gets hotter you can use even heavier oil, and you
can change springs too , you also want the buggy to sit level side to side and front to back , next is diff oil since you bashing through grass , dirt
etc you do not want a heavy of diff oil use 7000 front 5000 center , 5 000 rear , or 5 -5- 5 some guys for racing use 5-5-3 depending on track
the dirt , loose or hard clay jumps and turns , there's a lot of variables for the buggys , truggys nitro and electric also check what the manuals recommend ok hope i helped

Mugey, you're always a great help bro! I didn't think about the temperature affecting the shock oil, nice tip! I know I'm going to have to experiment with the different weights in both the shocks and diffs but mainly the shocks as I'll probably never race this buggy seeing how hard it is to find parts for now.

I'm trying to minimize the money I spend on it, thus why I'm asking some questions that could be answered by a lot of trial and error. Some trial and error is expected though.

If if I don't get the results I want then I'll start looking for better shocks from other models that will fit. I just need to find out what will fit it.

There must be something on the internet about other shocks that will fit the LX as it is fairly common and has been around for years.

Failing that just remove a front and a rear and measure the length...I will try and find a thread on another forum that had a few measurements of various cars.

Also do your shocks have preload spacers or adjustable collars to add preload to the springs? If the springs are weak or saggy adding preload can be an easy way to make it work within reason....of course the oil in the shock absorber is there to control the spring and the spring is there to support the weight.

I wish they had adjustable collars, but unfortunately they have spacers. I'll have to find something to measure them with in millimeters. I'll also see if my LHS has a set of springs in stock and try that out. Oil and springs would be the cheapest route but new shocks are not out of the question.

hi guff yes you can change shocks and springs ofna lx,shocks or one of the other ofna models think these are a little wider 15, 16 millimeter dia. these might work also maybe mugen buggey try the ofnawarehouse .com ofna store and ebay for a set measure using a caliper in metric and in standard 15 mill is .590 - 16 mill is .629 ( 5/8 in ) ok

Would I measure the shocks fully extended or compressed? Thanks!



I would've thought so too but I've struck out on the fronts especially. I did find something about the rears being 88mm. I'll still measure to make sure. Thanks!

Measure at full extension and centre of eyelets...the diameter of the actual shock does not matter much as there are simple ways to prevent the spring binding on surrounding components.

Also I prefer to have the spacers to alter spring preload...then you can just add the same to both sides...with adjustable collars it can be a pain to get both sides similar...

Anthoop is right measure extended and find shocks shocks to best match those dimensions if you are going to get newer threaded shocks for your buggy ok

Well, I picked up some diff and shock oil today. Ended up getting 5000 for the diff's and 50wt for the shocks. I'm going to try these out for now and see how it goes. I may just change the front shocks to 50 and leave the rears at 37.5. I can always pick up a different weight if I don't like it. Thanks again for the advice guys! I'll post back when I get a chance to run it and let you know how it turned out. :cool:

Got the diff fluid in and what a difference from just grease! It acts like a totally different animal, even ballooning the front tires slightly. I also put the same diff fluid in my Backdraft, although I may go with a lighter fluid in the rear on it.

Also put the 50wt oil in the front shocks but discovered a tear in one of the bladders. It still made a noticeable difference and I think it will be even better once I get new bladders in them. I'm going to replace all 4 bladders as I believe they're a little worn out. They're letting a small amount of oil get in the air chamber.

Thanks again for everyone's input!

It may be worth checking out eBay chop shops for a set of shocks for the newer LX1, LX1e, LX2, LX2e. I had your buggy and I know the lengths of the LX1 are very similar, LX2 shocks are same length as LX1 but with a larger bore. If you want to keep your shocks and try new springs look for LX1, LX1e springs, they'll fit. Sorry I don't have fluid weight recommendations.

As for the diff fluid weights, 7k/5k/1k, 5k/5k/3k or somewhere in that range are pretty common starting points. The common theme is to have the rear with a lighter weight. Since you're ballooning the front tires you may want to try upping the weight of the center diff, if you're at 5k I'd jump to 10k and you could always mix the two to bring the weight down to somewhere in the middle if you wanted to. But yeah, silicone fluid makes a huge difference over grease.

Thanks Maj, I'll try to look for a set of shocks on ebay. If I can find a set cheap I'll upgrade, if not then a new set of bladders are in order for me. As far as the diff fluid, I'll see if it calms down any before changing the center and rear as the center was a PITA to change. lol

Thanks!