johns
Expert Class
Posts: 205
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posted March 17, 2002 08:20 AM
superflow vs dynojet dynos
Anyone have any experience with dyno runs on the same bike on both a Superflow and Dynojet. The reason I am asking is I am getting substancially lower readings running on the Superflow at the dyno shootout in daytona than on two Dynojet 250's in my area. Last year I took the ZX-12 to Daytona and it made 187 corrected H/P on the Superflow at the shootout. The bike made 197 corrected H/P at home on a Dynojet 250 two days earlier. This year I took my 99 Honda XX to Daytona and it made 150 corrected H/P on the superflow. According to the superflow dyno sheet FOR THIS RUN this equates to 163 corrected H/P on a Dynojet. When I asked the Superflow tech why they included a column of corrected H/P numbers for Dynojet he told me they had so many complaints about lower readouts than Dynojet they put the correction factor for Dynojet in they're software as a customer service. They naturally feel that they have a more accurate method for measuring and computing H/P and torque. I am not complaining about the lower numbers (in fact I suspect the superflow readings are the more accurate),It just seems odd that two major manufacturers would produce machines that give such different readings. The engineering calculation for H/P and torque (as long as you compute for SAE figures)are the same for everyone.
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2006 ZX-14 (sold)
2012 ZX-14R (Brock's Perf. project bike Louisville Slugger)
2013 Honda VFR1200F
2003 124 C.I. H.D. Super glide
  
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted March 20, 2002 10:08 AM
Johns, I've used superflows dyno and DTS's and dynojets dynos. And there are 2 basic ways dynos measure HP/Torque.
They either use a heavy drum to control acceleration and measure inertia or they load the engine using an electrical generator or hydraulicaly with a water pump. Theres also another type for aircraft stuff that wouldnt apply in this case.
When an engine is made to produce a load agenst a water brake or a generator it usually reads lower even when dynamic loads are factored in. The computer on a DTS even corrects for the heat added to the water from load transfer.
Eddycurrent dynos use a generator to produce load and accomplish the same thing.
Some argue that an inertia dyno is more realworld. This may be true but if you want to know tha exact HP of an engine you need to stop all of its inertia and take an actual break torque reading. The computer then does the rest.
Thats not to say that an eddycurrent or waterbrake dyno cant do acceleration runs, because they can do that also.
I could go on forever but hope this helps.
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Y2KZX12R
CompetitionCNC.com
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mrfast
Expert Class
Posts: 114
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posted March 23, 2002 08:09 AM
HP=TQ x RPM DIVIDED BY 5252.This may be an idiotic question but does anyone know where the 5252 comes from? HP and TQ are always the same at 5252 rpm?
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