AC Racing HVO Slip on

[jdub03]

Anyone running one of these. Supposedly they make a quiet core insert which drops the db's 93-95.

[jdub03]

Anyone hear of CHM, or Scorpion both companies make full & slip-ons. I believe scorpion make a header that will bolt on to a factory silencer.

[m.h.s.c.#527]

Originally posted by jdub03
Anyone hear of CHM, or Scorpion both companies make full & slip-ons. I believe scorpion make a header that will bolt on to a factory silencer. saw the scorpion in dennis kirk or maybe it was acropovic

[jdub03]

I can't find scorpion phone #. If anyone can find it or knows it let me know. I'm trying to get specs on the header they sell. I want to verify it fits the factory silencer, and find out the diameter. They list for $129, but I found a shop selling them for $55. Might be worth it.

[ryanh250ex]

Buying a header that fits into the factory silencer is kind of a waste of money. Headers- on bikes and ATVs, anyways- make their gains over stock headers/exhaust manifolds by different bends and a larger diameter of piping. If the piping is the same as the factory header, that means there is very little to gain from it.

Furthermore, by choking it up with the factory silencer, you are eliminating even more of the possible gains typically found in an aftermarket exhaust.

Don't get me wrong, I'm totally for quiet exhausts- but there are better ways to do it than what you're suggesting.

I recommend either the Pro Circuit T-4 (what I run) with their quiet core option, or the HMF w/ quiet core.

[jdub03]

If diameter of the piping is larger up until the end where it goes into the silencer and the bends are smoother. I believe the gains could be ok. When putting a set of headers on a car most of the time there made to fit the factory down pipe or the factory cat. Obviously the gains are greater if you include the cat-back, but there still are gains.I realize that its gonna choke up with the factory silencer, however I believe there gains to be made. Might be worth the $55. Might not be. Even if the gains are neglegable I could always add a silencer later on. If I need to change the header pipe then. Then I'm out $55. Of coarse this is only worth it to me if the header is larger diameter and a better design.

[ryanh250ex]

Originally posted by jdub03
If diameter of the piping is larger up until the end where it goes into the silencer and the bends are smoother. I believe the gains could be ok. When putting a set of headers on a car most of the time there made to fit the factory down pipe or the factory cat. Obviously the gains are greater if you include the cat-back, but there still are gains.I realize that its gonna choke up with the factory silencer, however I believe there gains to be made. Might be worth the $55. Might not be. Even if the gains are neglegable I could always add a silencer later on. If I need to change the header pipe then. Then I'm out $55. Of coarse this is only worth it to me if the header is larger diameter and a better design.

Your points are valid, but if you really want to get technical about it, there is much more that goes into a header or set of headers on a car, compared to a single cylinder ATV motor. In cars, gains are made not only through piping diameter (increased flow) and different bends (increased velocity), but also scavenging (affects velocity AND flow), various collector designs, and the list goes on and on...There really isn't any consideration like that put into a ATV header, because it being a single cylinder, generally speaking there doesn't have to be. You dont have more cylinders firing, or even other cylinder banks for that matter, affecting the timing and delivery of the spent hydrocarbons throughout the exhaust.

Ideal exhaust design is a steady taper from the exhaust port to the silencer/tip. by necking the header down so it can mate to a factory part, it acts as a bottleneck. of course you can easily cut and re-weld that portion so that it continues tapering larger, but all in all i think you would be much better served the first time around by spending the extra money on a full system. I speak with experience on this one. ;)

[jdub03]

I understand your point & I will keep it in mind. I've had more experienced in modifying cars than Atv's. They are a little new to me. But the basic concepts still remain the same. Thanks for your reply's.