Performance exhaust

[bwiggs2]

I am looking to buy a gy6 performance exhaust, I would like to get one before new years.. Anyone have one or know what store?
Thanks, Blake

[SYCARMS]

What brand buggy do you have? I carry the eastside copy as well as the TK from Spain. PM or call me with any questions. e-mail< tom@sycpowersports.com >

[bwiggs2]

I emailed you

[xlint89]

OK, so I asked on the "other" site and I always get really vague answers.

Can anyone please tell me what the difference would be if I used a complete exhaust sytem VS, just a slip on silencer?

My FMF slip on is wayyyy better than the gutted stock muffler.

But I can't help but wonder what the complete exhaust sytem would do....

You've got the Hammerhead

http://buggypartsnw.com/home?page=sh...&category_id=6

It looks like a wider header pipe, and about the same length as stock. Basically looks like a bigger header and a slip on muffler as well.

You've got the MRP full length.

http://www.bing.com/images/search?q=...78DE72&first=0

Looks to have a much longer than stock header with 2 "steps" in bigger size pipe.


And finally the "custom tuned" full length exhaust

http://sycpowersports.com/index.asp?...id=66&incid=29


Looks to be just as long as the MRP header, but with only 1 "step" in pipe size.


Can anyone please tell me what the difference would be?

Has anyone ever dynoed any of these VS. a stock exhaust? Thanks

[SYCARMS]

The East side tunned exhaust which I have on my web site is no longer available. It used to be the best one out there since it was a true tunned exhaust. The MRP is better than stock and better then the fmf slip on but it is a copy of the east side and not a tunned system. Same with the hammerhead system not a tunned system . A tunned exhaust is tunned using a dyno with the process being very lenghty. This is why a tunned exhaust costs several hundred dollars. The only exhaust today which can be claimed to be tunned is the TK exhaust out of Spain. The 2 buggies used for the tuning process were the Kinroad 150 and 250 sahara. Both were done with stock engines, no jetting, stock variator, airbox ect. They showed a 15 % and 12% gain in power, a 1.35 HP gain on the 150cc. A true tunned exhaust will give between 10% and 15% depending on the stock configuration of the engine.. Now do you really need a tuned exhaust over an fmf or one of the other performance exhausts. It all depends on what you want out of the vehicle.. If you are racing or just want more performance then its needed in order to get the most. Just because you put a bigger muffler or bigger pipe on does not mean you will get more performance. The exhaust is the last step in the performance cycle. Too much restriction and your exhaust gasses are not getting scavenged so along with the fresh mix of fuel it will de deluted with exhaust gasses. In Al Gores eyes this is wonderful since this will help burn the unburned hydrocarbons but performance goes to the trash bin. Too much exhaust with no restriction and you loose some fresh mix during valve overlap, now Al is crying. So a tuned exhaust is escential for the proper scavenging of the exhaust gasses.


TOM

[x-bird]

Dang tom, you treed me!

I'm not trying to be a wiseguy or put you down whatsoever, but please read on keeping that in mind ...
you're asking a very specific question about the one upgrade that is likely affected the most by all the variables that can exist in and around an engine. Whether or not an exhaust upgrade or change will perform better than another can differ vastly between nearly identically prepped engines. exhaust systems function and should be designed on intake flow in and through the head (with the flow numbers generated with EVERYTHING in place--not many bench ops are willing to rig the entire induction system at their bench) AND also for how/where the power output is desired. engine building for peak performance isn't voodoo, it's very systematic math, but without the proper knowledge and tools few people can achieve the creation of complete engine that gives the best volumetric efficiency for its displacement.
The only person really with the answer to "Which would be best for your engine" would be you after trying them all out. Of all of the tech articles I did, exhaust comparisons were always the biggest nightmare. Days on the dyno running and rerunning and watching little changes completely flop results. Yes, throwing a header on a pretty badly exhaust-restricted engine can give good to great increases for every engine in that situation. Then try another and see those increases at a different locations in the powerband--maybe more maybe less. Which is better???? Depends on what the end user wants. Change a carb and manifold and watch an equal tube header get killed by an unequal setup, or singles tubes wipe a Tri-Y only for the tri-y to have a really nice bottom end burst to them but not be able to handle the upper rpm flow levels. I've seen ugly, pitted but lovingly home hand-ported cast iron stock manifolds mop the floor with mandrel bent high dollar headers -- only because they were ideally worked to flow what that particular engine wanted.
Honestly, you're asking for info that only a rare few likely have a complete "X with Y is better than X with Z, but Y with Z is dynamite!" answer.

Now, with all that drivel written, if you have a stock headpipe and you have either increased intake flow, upped the cubes or done other work that has left the Intake/Exhaust flow ratio wanting better numbers on the exhaust side, then logically, you'd want to start by putting a bigger outlet on the exhaust (I have yet to study the heads on these to see if anything can be easily ported and whether port-matching is needed or worthwhile).

You have half your answer in that a less restrictive muffler helps, but you can also hurt performance by losing too much velocity. (going too big) Feed that gutted muffler with a larger pipe first and see what happens. Maybe then try a stepped pipe. Then add in whichever hi-po muffler tickles your fancy and try that on your stock pipe, your straight pipe and your stepped pipe.

But even before that, I'd try and find out who some of the "old school" engine or header builder names are in the racing go kart world and make a few calls. You'd be surprised at how receptive some are. Vague answers to this one on a forum are nothing to be insulted by, i bet between all the dune buggy and karting forums, (there are a lot of them too!) there's only 1/2 dozen to a dozen guys (likely race teams) who've "scienced" out all the applicable systems to their engines to find the ideal setup--and they probably guard that info like fort knox.

BTW, my bird is on its 4th variation of its 5th exhaust system --over 15 variations in 12 years.
When one asks what a bigger tire or different gear will do --lots of fast answers because it's pretty easy math. Start asking about exhaust and don't be surprised by all the crickets ...

[xlint89]

Definately not vague answers here......


Tom, thank you for that explanation on the tuned exhaust. 10-15 % increase is quite substantial.

What's the going price for the TK exhaust if the East side is no longer available?

X-bird, thank you for the very detailed response. I really appreciate that.

I do know what you speak of since I'm always modifying everything with an engine. Same applies to my Sportster and truck. The 2 Stroke PWC, not exactly.

It is good for newbs who don't know to read your post. Now they have an understanding that it's not quite black and white when it comes to things like exhaust selection.

HOWEVER, I figured since most of us have the GY6 150 with the common, UNI filter, redneck extension, coil, CDI, carb rejet upgrades, and are pretty much looking for the same gains that there should be an apparent "winner" if you will.

Most of us all ride the same type of terrain, and are lookng for down low TQ for hill climbing, but I'm actually after a bit more top speed myself.

Someone did respond with some #'s on the Hammerhead exhaust though. It appears BD has gotten a dyno and posted the HH exhaust gain is about 6% or almost 1/2 HP over stock.

Tom's response of the tuned exhaust gainig almost 10-15% is what I'm looking for. So for the little extra $$$ over the HH, you can get almost twice the power potential.

Thanks guys!!!!!

[SYCARMS]

You are correct in what you say, however the question asked was if a slip on is as good as a complete exhaust.Now I do not know if TK used a flow bench or not but I assume they did, and know they showed gains over stock on the dyno. No one else has done this except for the eastside exhaust. Any body can put together a larger pipe and free flow muffler and then call it a performance system The difference between the eastside and MRP from personal experience is pretty noticeable. Now for the 250cc you have the Hammerhead and the MRP which are basically the same. Size of pipe and length and mufflers look almost identicle internally. I ran the MRP on my 250cc and could not get rid of the flat spot on rapid acelleration. I just let everyone convince me it was the cv

carb and that I needed either a pumper or a slide carb. I put the TK on to try and the flat spot went away but the biggest difference was at about 3/4 throttle the motor come alive.Now will it perform this way with a stroke?? Now the average person will be perfectly content with a slip on since they will tell a difference in performance over the highly restricted stock muffler, but their are those who want more performance. The sad part of it is the chinese parts market is ripe with the word performance but with nothing to back it up.Now when I started messing with my heads on these buggies I asked a lot of questions and one person in general who designs cams told me that he had an uncle who worked years ago for the Ford racing team and from the books he told me to read and the story's from his uncle the flow bench is something some totally relied on but that a good builder will use it only for a reference point since there is such a thing as too much flow and the only way to check the end result is on the dyno. You are also correct when you talk about the complexity of volumetric efficiency for it is a science that most know very little. I know some from reading and consulting with people but it sometimes does not take someone with knowlege long to loose me, and I am not an expert on the subject but just a novice. Now I believe the question xlint89 origionally asked was if anyone can tell what difference the exhausts make over a fmf on a stock pipe and if anyone has ever dynoed the exhaust vs stock exhaust. I give him my answer based on what I had personally experienced and know with the East Side, MRP,FMF,Hammerhead and TK exhaust. I respect your knowlege and wouldn't mind meeting and or brainstorming some day. By the way where the H*ll is Penciltucky LOL


TOM

[x-bird]

Originally Posted by SYCARMS

By the way where the H*ll is Penciltucky LOL
TOM

Just a few hundred yards west of Dixie (pic)

I wrote up my post while you wrote and posted yours, didn't see yours until after mine went up, which was directed entirely at xlint's question. You hit the nail on the head with a lot less words.

After many years of playing with cars and having the good fortune of working in some low and high end shops then later the automotive magazine biz and getting a lot of first-hand education from everyone from enthusiast owners to some of the top race builders I still consider myself a rank amateur. The issue of commercial vs consumer interests is the main reason i left the magazine biz. In the late 90s the automotive and largely the entire magazine industry became a publishing monopoly of the company I worked for. (I started out with a small niche publisher putting out a dozen monthly and bi monthly car pubs that was soon gobbled up) The higher ups basically forced article write-ups and company/product coverage on the editors solely based on advertising revenue. It actually was "forbidden" to write about a product from a company that didn't advertise with the mags and woe to he who wrote the negative outcomes without couching it in BS gilded lily prose even if it was the truth. Guess where this square peg didn't fit .



Back on topic, even these china gy6s have enough variation in them (heads, valve sizes, cams, carbs, gearing etc. that there's no real guarantee that what works for one will work for another. Your example of your experience with the flat spot in the powerband proves that out.

It's great that a person like yourself has the knowledge of what's out there and takes the time to pass it along untainted by commercial interests. Given the economic and manufacturing situation these days, it's a lot easier for the average end user to waste a lot of money on hype and a lot harder to get solid, factual information.

[SYCARMS]

I too fell victim to corporate greed after 25 years, planned on doing this full time at a little later date but as life goes, plan one abort, try plan two.

TOM