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CBR600F4i Coffman Shorty Dyno Graph

  #1  
Old 12-07-2018, 08:20 PM
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Default CBR600F4i Coffman Shorty Dyno Graph

There's nothing out there on the net about the power curve of the f4i with coffman. I had done a run with the coffman on. It does lose heaps- have a look.​​​​​​​

Dyno printout of CBR600F4i with coffman exhaust
 
  #2  
Old 12-09-2018, 03:54 PM
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Thanks for posting but I can't read that printout very well. Is that with the baffles in? How much loss is there? I hate the thought of going back to a stock pipe 'cause the Coffman sounds so good!
 
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Old 12-10-2018, 03:00 PM
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Clicking on the link just shows me the very top of the page not the actual dyno at all.....
 
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Old 12-11-2018, 02:28 PM
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hi, this was with baffle. Btw. in one of the runs the exhaust was almost blown away, I had used a smallish rivet. so make sure your rivet is big and strong.
posting an enhanced version of the above pic

 
  #5  
Old 12-13-2018, 04:06 PM
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Sweet. Very surprised at the low number, even more surprised a slip on actually lost power.
 
  #6  
Old 12-14-2018, 04:04 PM
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Well, look at that pipe. At best it’s just an extension of the collector. Only slightly wider. Besides I ran it with restrictor in. Without it I suspect top end would be slightly better but it’d be obscenely loud. But the dip in the midrange was very noticeable. Very. But it looks very nice on the bike that I’ll give it
 
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Old 12-19-2018, 04:27 PM
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Originally Posted by ceebeeaarguy View Post
Well, look at that pipe. At best itís just an extension of the collector. Only slightly wider. Besides I ran it with restrictor in. Without it I suspect top end would be slightly better but itíd be obscenely loud. But the dip in the midrange was very noticeable. Very. But it looks very nice on the bike that Iíll give it
Was there a run with the stock exhaust? If so, how many hp were lost? If not, is it possible that the baseline (i.e. stock setup) was lower than average to begin with?
 
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Old 12-20-2018, 02:52 PM
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Originally Posted by Doc Samson View Post
Was there a run with the stock exhaust? If so, how many hp were lost? If not, is it possible that the baseline (i.e. stock setup) was lower than average to begin with?
Excellent point. Just because a stock F4i is around 95rwhp doesn't mean it makes that much on that particular dyno.
 
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Old 12-28-2018, 01:55 PM
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Originally Posted by boredandstroked View Post
Excellent point. Just because a stock F4i is around 95rwhp doesn't mean it makes that much on that particular dyno.
Originally Posted by Doc Samson View Post
Was there a run with the stock exhaust? If so, how many hp were lost? If not, is it possible that the baseline (i.e. stock setup) was lower than average to begin with?
Hmm, I guess the only way to tell is to have a dyno run now. I'd be doing a run in Jan, will post the results here.
But that won't be with a stock exhaust. I now have a Yoshimura race can and really the setup is basically a stock F4i motor with FX/FY headers, linkpipe and can. So it's not really a stock setup.But I guess a run now should give you decent idea about how much stock is as I don't think an FX header and a race can can magically lift the power band if the base is this bad(assuming coffman didn't lose much, the bike was a pig even before)
Frankly, seat of the pant feel tells you a lot and that dip was really noticeable. You don't need dyno to notice obvious crests/troughs in the power band. Before the coffman I used to have a scorpion stubby exhaust with baffles not removed(with f4i stock header, link pipe etc)and the bike had good meaty midrange. After getting the coffman, the midrange was gone and that dip you see above was very very irritating. I am unsure if it was any better with the noise reducer out as I never tried it.

Wish you a happy new year guys. have a good one!
 

Last edited by ceebeeaarguy; 12-28-2018 at 01:59 PM.
  #10  
Old 12-28-2018, 02:23 PM
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Thanks for the follow-up! Now I'm tempted to put my stock can back on this spring just to see if I can tell a difference...
 

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