I know that end results don't necessarily matter since it can vary dyno to dyno and it's the % gained that truely counts but do my HP/TQ numbers seem accurate. I haven't really seen any other numbers for specifically for these pipes. Question is what should be next? Go to a 2 into 1 pipe? Cams? Headwork? How much do I stand to gain?
Vance & Hines Big Radius 2 into 2
S&S tear drop intake
That seems way high for those pipes (what correction factor did they use?), the wifes V&H short shots come on strong but drops off fast (63hp/74ft with qt baffles and inserts). I ran a Supertrap Supermeg with 20 disc and closed end. Both bikes were 2009s Nightsters tuned with a SERT, on the same dyno with the same operator with the same air cleaner. No other mods. The qt inserts probably robbed the SS of a little power but you can see a clear gain between 2-2 and 2-1 exhaust.
"For those who care, I do not"
Last edited by cotnballs; 20th December 2011 at 16:43..
Location: The Center of the Sportster Performance Universe
Sportster/Buell Model: XL883
Sportster/Buell Year: 2007
Sportster/Buell Model #2: Buell Cyclone
Sportster/Buell Year #2: 1999
It actually says CF:JIS and then Smoothing:3
The CF is telling you the correction method. There are a bunch of different ones you can choose from in the Winpep software. Depending on the algorithm used (i.e. how it goes about factoring enviromental conditions into the correction), you get a radically different result number.
Most people publish SAE corrected numbers in this country. You can see in Cotnballs charts how they were done with SAE. Using something other than SAE to make the numbers look bigger is a pretty common practice though. You mostly see people use STD to make the numbers look bigger, but sometimes you see some of these foreign correction methods used as well. It always makes me suspicious when I see someone doing this. I know of one shop that has ALL their dyno sheets on their web site done in STD just to make their numbers look bigger, for example. They just assume that most people don't know any better.
Turning down the smoothing is another technique that some people use to make the number look bigger. Basically you're trying to get the max numbers to reflect one of the little spikes.
SAE correction and smoothing 5 are the types of results you see most, like Cotnballs charts.
Thanks Aaron for the quick response, I found this link that also explained my question with multiple Dyno runs using a few different correction factors and and smoothing showing how oppperators can manipulate dyno numbers to look bigger than they really are.