Summit = pacesetter shorties?
The Pacesetter longtubes? Not to say they shouldn't be used just that you need to match them to the system they are being put in to approach/equal well matched shorty performance and don't expect those kind of numbers unless you are pushing a $#1+ ton more air than stock and can really pressurize them so velocity stays high enough to get those bad boys really scavenging in a noticeable way.
Same eBay seller has some listed for $108 + $39 shipping
V-8 engines are not particularly sensitive to primary tube length ... as long as they are a certain minimum and not too long, but primaries that vary over a range of 12~18" there is not much evidence you need to worry about it.
The firing order and crank degrees between firing pulses on a V8 plus exhaust ports being on two sides of the motor mean equal length primaries for pairing of cylinders to help scavenging isn't really possible. That's a big deal with 4-cylinder engines especially and can work on a (inline) 6, for street performance. On a race motor you go 4-1 anyway, which is what works on a V-8 as well.
All engines are sensitive to collector length and configuration though; something that isn't an issue with shorties designed to mate to stock exhaust. Long tubes will by their nature require you to fab something there, so you may as well discover what works while you're at it.
It might be worthwhile to explore that with the usual shorties instead of using the stock pipes. Fabrication and welding involved, and let us know how it works out since nobody has done it on an OEM Magnum vehicle as far as I know. May not be worth it with shorties but you never know. Some OEMs do pay special attention to the secondary pipe length and make them equal length on V-engines between the header collector and the cat.
They have a term for it that escapes me now but it's something like "quasi-dual exhaust"; in essence they are equal length duals from the collector up to the 2-1 at the single cat. I read an SAE paper on it once where one of the Japanese OEMs showed torque and powerband improvements on a V-6 engine configured that way versus the unequal length secondaries common on more mundane cars and trucks.
Basically on the Ram you would lengthen the passenger side secondary to equal the drivers side, which you could leave alone. The Japanese OEM just used two u-bends instead of going right from the collector to the cat on the passenger side, so it didn't really take up any more space, just a bit of height clearance required over the straighter pipe.
A set of 1 1/2 longtubes might prove better at torque improvement over the same diameter 1 1/2" shorties but there are none as far as I know for these engines so it's moot. (If you find some, post back because i'd be interested. A 1 5/8 might be better still, either as shorties or long tubes, since that should still preserve bottom end torque on a 5-ish litre engine but we don't know for sure; they don't seem to exist either).
The 1 3/4 longtubes will benefit if you are looking for higher RPM power improvements. Other engine mods would be recommended, and power down low will probably suffer. All in all for most of us the 1 1/2 shorties are a pretty decent compromise that offer some power benefits without turning our working trucks into un-streetable cars.
I built an exhaust designing database many years ago but the SW it runs inside no longer works on a modern OS. Maybe if I get time (yeah, right) I will put the equations into a modern app and punch in the numbers for the Magnum some day. But after running hundreds of simulations through that years ago, I would be shocked if 1 1/2 or 1 5/8 wasn't the way to go with these engines. The shorties might be a little short but not by much, and I suspect you wouldn't find a lot of power if you went longer at the RPMs we use the motor for daily. There might be some torque to pull with longer tubes. Maybe.
Last edited by Johnny2Bad; Mar 18, 2012 at 07:07 PM.
Isnt that what I already stated??
? there's a few older auctions of his that haven't ended yet but it looks like hes raising his prices by 80 bucks because they were all 108 before.
? there's a few older auctions of his that haven't ended yet but it looks like hes raising his prices by 80 bucks because they were all 108 before.
dont buy the ones from the other sellers.... I have compared flange plate to the other ones pictured and they are in fact cut totally different.. you will have to do trimming to get hem to clear the plugs
Now I wonder if they're CARB exempt...................
actually its dirt cheap for stainless steel headers...
gaskets are great but the bolts are the wrong ones,,, you want 1" grade 5 or 8 5/16-18 bolts...tell the seller you heard the bolts were wrong from here (point him here so he ca see others have verified it) and he might cut you a deal.




