Whoa, whoa, whoa, hang on their snoopy. It’s not that I disagree with you fully. Even what you are “arguing” was my may of thinking in the beginning also. Tis why I spend the time on the inserts in the first place.

But you’re argument becomes futile when you sit and argue logic and I argue dyno tested results doesn’t it?

You’re arguments will hold water when you have bolted an engine on a dyno and tested all the scenarios. Until then, your argument holds as much water as a burlap sack.

The carb inserts ARE NOT velocity stacks.

hey billyman i sent u a PM i dont know if u chcked it tho

I did, and look to hearing from me in a few days.

Thanks man.

They are, just not optimized to the fullest extent.
I'm not saying you are wrong that taking the inserts out will give more power, just that you can get even more power if you shape the intake better. Without the inserts it's far from a optimum or close to optimum shape.

If I had a lathe I would make my own velocity stacks.

You are aware that air “turbulence” increases fuel atomization and increases torque right?

STOP!!!! Do not “google” fuel atomization for your answer. I’ll know if you have.

Hmm, it’s going to happen and what you’re about to do is known as plagiarism. While you’re out “googling” find and purchase yourself a dyno and put it to work.

WTH is your problem dude?!

Use your dyno and make more test!!! I am interested!!!
Take a stock carb with no insert --- test it.
Take a stock carb with no insert and shape the intake --- test it.

What don't you get through your skull? I never doubted your dyno results.
[sm=confused.gif]
Are you afraid?

I tried to open the link, but there was nothing there. Is there a way you can put the photo in your gallery?

Thanks

Have a question concerning the steering on a Mayhem, the stock steering link has always worked loose on me after a few runs, So I picked up what I thought to be an upgrade from Sportwerks, however it is titled the "Ackerman Steering", and is quite a bit different then the stock arm and comes with a great deal more hardware and no instructions. I have not seen this type of system prior to this, and would welcome some assistance. Has anyone installed this? Or have some knowledge of where to find out if it is worth installing, or maybe a site I could refer to for installation.

Here's a top off and potential end to my experience with my new Mayhem.

I finally got all of the fasteners that were too short replaced and loctited. I also got all of the other screws (metal to metal) loctited. I finally got the engine down and tuned. I took it out last night for a first all out run to check temps and do some full throttle sprints to get an idea of what I have. After doing what I thought would be my final adjustment, I was running the buggy in a large parking lot. Although I'm running a Spektrum DSM, I lost radio contact with my buggy. I was also running an Ofna fail safe, just in case. While running wide open, I noticed that I had lost steering, but didn't immediately freak out. After all, I had the failsafe and the DSM system, when it looses contact with the Tx, will by default move the servos to their centered position. Well, after a few seconds, I did start to freak out. The buggy didn't stop and ran full speed into a foot tall concrete curb.

When I got the buggy back home, I assessed the damage. Bent chassis, chassis braces, rear shock tower, center dog bones, cvd shafts, servo tray, broken servo cases, and other stuff that I haven't found yet, I'd imagine.

Well, I took the buggy apart to salvage what I could and when I pulled the servos, I noticed something. The ground wire on the throttle servo has a very neat cut right through almost all of the insulation. It would seem that the cut had been there all along and the wire was making connection by a couple of strands. Somehow, during the evening of running, the remaining strands broke and that's why the buggy didn't stop. I didn't catch it while going through the buggy because the cut was in the middle of the "stock" bundle of wires in the electronics box and it was zip tied from the factory. I didn't see any reason to disturb it, so I left it alone.

Man, oh man. It just makes me sick to think that I could have bought a Cen or XTM for around $300. Oh well, I ordered the parts on ebay. It cost me around $150. I'm gonna try to put it back together again. I'm just waiting to see what happens next.

I emailed Horizon about the whole thing. Maybe they'll do something about it. I'll see.

On the plus side, the engine never killed through out the whole thing, so at least I got that part right. Maybe I'll just drop the .26 into one of my X-Terminators.

Oh, I did forget to mention something and I found this a bit peculiar. I didn't break a single plastic part. The only reason that the servo cases broke was because the servo tray bent.

better check the eyelets of the lower suspensionarms though
they could have microscopic cracks
and break on the first high jump
you take the wrong way...

about the ackerman steering plate

I have a comment of Speedbump=

I no longer have the Mayhem as I am now driving for Ofna.
I will however help you in anyway I can. When you put on the new ackerman plate it introduces a whole lot of what’s called bump steer. What I did to remove this was to take a ball end like the one used on the front or rear sway bar mount and place it on the bottom of the new ackerman plate in place of the stock one. What this will to it lower the steering tie rods almost back to where they were before. I seem to remember also raising the other end on the steering knuckle as well. It will work the way you have it but it will be unstable in the rough stuff which the Mayhem does not like anyway so if you can do that with the different ball end you will be better off. When you make a change like that most always you have to readjust the end points on the steering. I would check your steering end points and make sure you are getting full throw and then do the mod when you can.

Let me know if this helps.

Bump

Not being argumentative here but could you explain where this “intake” is that should be shaped?

Are you referring to the carbs upper portion of the throat? Have you actually paid attention to how thin this thing is especially on composite carbs? Outside of a quick chamfer of the rim, there is nothing you can do to it.

I don't know about dyno results or intake shapes, but after reading the above posts, I took the venturi (is that what it's called?) out of the carb, then tuned it for the larger intake hole. The speed and power are insane. After doing this, I could nail the throttle from a dead and the car would do a 360. The top end was noticeably faster.

I think I'm going to take the smallest insert and chuck it up in my lathe and turn the inside out at an angle. Perhaps, starting out at the widest possible opening at the top and then tapering to the size of the intake at the bottom will result in an air "acceleration" effect. Who knows, I don't have a degree in engineering, but I may stumble onto something. As far as the 9mm minimum requirement, do they go by the largest diameter of the opening or the smallest?

hey billy man, sorry to be a nag, but whats the deal with the mayhem... im in need of money, thats all.. let me know whats up

The smallest is what tech goes by but noticeable modifications may not pass tech inspection.

Thank you for trying out what I was preaching. The power increase is unreal in both bottom and top end.

As far as modding an insert: The problem I ran into with trying to get maximum flow and a smooth air flow with the insert was getting it big enough to make a huge difference over stock difference. After about 11mm enlargement you become dangerously close to cutting into the ribs that are cut into the outside of the insert for the O-rings. If you’re off center, you’ll cut into one of these ribs or grooves before you get to the inside diameter you desire. But hey, give it a shot, see what you come up with, experiment a little.

Rock on!

turmoil :
they still didn't do anything about that silly tank....
outlet tabs should be at the sides, not top

OK, this is what I did. I chucked the smallest carb insert (which I'll never use) into my lathe and turned out the inside on an angle to give it sort of a funnel shape. I put a roundish taper on the outside edge by hand while spinning it in the lathe. I then bead blasted the inside to take off any sharp microscopic edges that the machining process may have left. I then polished the inside using jeweler's rouge.

I then tuned it on the bottom end as it should be. Not too rich and not too lean. I tuned the top end a tad on the lean side. I usually like to run my engines fat, but for these testing purposes, I went a bit lean.

After testing it, I immediatedly pulled it out and went with one of the smaller inserts. With the modified one, things were just too loose. I could't control it for anything. If I started it and let it warm up, then stomped it from a dead, the buggy would spin. I don't mean that the wheels spin, the whole buggy did. For those of you that are older and liked the Sunday morning monster movies of 30 or so years ago, it reminded me of Gamera the flying turtle. In the dirt, it was just too touchy. Anything off of idle just produced too much power. Maybe it would have been better with some .9 or 1mm springs in the clutch (I'm running 1.1), but I didn't feel like pulling the engine to check it out.

I don't know. If you want insane, something like this may be for you, but it isn't practical. The runtime also took a nose dive.

Well I have gone and gotten a new MILL for my Mayhem. The track I run on is pretty short so dont need alot of top end. I went with an OS RG .21 and of course I had to buy the JP-1 to go with it. So Looks like this Sat I will be stripping down my Mayem to the chassis and getting it ready for Raceing. I am so stoked I can not wait to get this motor broke in and get out to the track now....

The RG .21 is tops in my book. It isn't the fastest or quickest, but it starts everytime and holds a tune really well. Mine does fine on a tight track. It does have a better than decent bottom end.

My Mayhem RTR .26 ... Ran fine on Sunday, started it up today and it runs in reverse. Turned it off, checked all my connections, started it up and it only runs in reverse. What could it be? I guess my motor is running backwards...

usually in boats that means its too lean soo it backs fires making it run in reverse.. i might be wrong for buggys tho

I had that problem before. I have no idea what it was but from what I remember I had to clean my one way bearing. what are you useing to start it?

My one way bearing has been slipping alot lately. I start it with a roto start wand.

I guess I will start with trying to clean the one way bearing. Is there any other way to do that instead of taking the backing plate off the motor?