Rear Wheel Horsepower?

I would like to conduct a survey of the current listers that have had their bikes dyno tuned and have actual rear wheel horsepower numbers. What year is your bike, what mods have been installed and what ya got under the hood so to speak?

I do not have figures for my current bike (91VFR750F) but I suspect it to be around 82 ish. I plan to have it done this spring so I can tweak my jetting and then I'll know for sure.

I'm just curious how far the bike has progressed from 1st gen to 5th and 6th?
I know that the VFR is not a race bike but I believe that the quest for improved performance is not limited to the race replica bunch.

 

Hey Jethro:
I think yo may be selling yourself a few ponies short. The 91 year model did not change much from the '90 model, which was rate at 92 hp at the crank - so that would (and by all reports does) equate to around 80-82 hp at the rear wheel - completely stock. I've looked at your pictures, but can't tell if you've gone with a slip-on or a full exhaust system - that obviously would make a big difference. An finally, did you match your exhaust upgrade with any intake upgrades - K&N and/or Jet kits.
Back a few years ago, I did the meat of the work to mine (2Bros full system, stage II kit, K&N), however I've never had it dynoed. But I can tell you the improvement is vast - I would estimate at least 10 additional horses and some additional/noticeable torque.

 

You may be right as I have not had this bike dyno'd. It has a full 2bros system and it has been rejetted so perhaps it is stronger than that. Actually I believe that you are correct as it is quite a bit stronger than my stock 90 was and it dyno'd at 78 rwhp just as the magazines reported that it would.

I just bought a 98 vfr800 with a micron slip on installed. I wonder what it will make?

 

'98 with K&N, M4, and PC-2.

 

Funny you should ask this. I just dyno'd my '01 last Thursday to get a baseline measurement before some modifications. It was done on a Factory Pro EC997 dyno at Nault's Windham Motorcycles in Windham, NH.
It showed a max of 82.9 HP at 9450 rpm.
Surprised ? don't be. Dyno's vary widely as do dyno operators. Dynojet dynos typically read 12-15% higher than Factory, but Factory is a correct dyno. Read more about Factory dynos here: www.factorypro.com
and click on 'EC997 Dyno Information'.
I've swapped out the stock FPR @ 36 psi for a Turbocity FPR @ 42 psi
and will be installing a BMC air filter, then dyno again to note changes.
I remember dyno'ing my '91 VFR750 years ago on a Dynojet dyno and recall seeing 84 HP.

 

Very interesting subject. Had my VFR Dynoed back in 96 and was stock with a HP figure of 96.8 to the ground which somewhat matches what Honda says. Now my 97 has a KN filter and Staintune saw a run of 103.1hp. with stock jetting, Not sure the name or type of dynos, they both looked the same to me and the set up was also the same, so for me I'm satsified with the results. and my seat of ther pants test tells me my 97 pulls stronger. FWIT I also run Amsoil .

 

Really small horses

Scott is really right. Dyno results really depend greatly on the Dyno and operator. I've personally seen 18hp differences from the same bike on different Dynos.

It's amazing how many people dissapear at portable Dynos when they see V-Twin read outs at 50 hp. This includes Metric V-twins too.

By the way, if you think a pipe, jets ,and filter get you 10 real back wheel horsepower, I have some property on the Gulf Coast that I'd like to sell you.

Maybe 10 Shetland ponies- but not Clydesdales!:drum:

 

Back in 1990 I ran my stock 1990 VFR against another 1990 VFR with a prototype Hindle system installed. Lange Hindle was there to witness the comaprison and is was run on a portable dynojet machine operated by Peter Hoogeven of Dynotronics. Peter is also a rather well know iron butt rider. The results were notable not for peak horsepower but rather for the curve. The Hindle bike did make a tad more HP through the RPM range but it continued to make HP till it hit the rev limiter at around 12k rpm. At 10,500 rpm my stock bike had given up packed its bags and was headed for the locker room. At 11,500 RPM the Hindle bike was making over 50 HP more at the rear wheel! I've long since thrown away the reports but Peter may still have them. After the run we had a little ride to compare them on the street and the difference was very notable during any kind or roll on. The Hindle equiped bike walked away from mine and it sounded great as well of course.

If you plan to make changes, get a baseline and make sure that subsequent data comes from the same source under similar or identical conditions and look for the delta between the two for you improvements and or losses. Another tip, do not ovettighten your chain! It sucks up power like crazy.

The bottom line, in my experience, yes you can see a 10 hp gain especially if your bike has a weak top end due to flow restrictions in the intake and or exhaust. I've seen it and validated it on the street. I'll pass on the swamp land offer though.

 

Incredible increase

As a person that has been involved in engineering for many years, if Hindle actually got 50 extra HP with a pipe and tuning, his pipes would sell a lot better. Monkeys would fly out of those cannisters as well.

By the way, riding through Gulf Coast Swampland adds at least 50 Shetland ponies (big ones though)!

 

Well it wasn't that Hindle actually made 50 more ponies, it was the fact that my stock bike fell off so bad after 10,500 that made the huge difference while the hindle maintained through to redline.

Are we going to compare credentials? I'm not full of ^%$$&. The Hindle made about 8 peak HP more than my stock bike at 10,500 which was somewhere near 85 and it held that till the rev limiter. The stock VFR dropped off rapidly after the peak at 10,500. The difference at just over 11K was huge.

You don't need to be an engineer (aircraft engineer for 18years by the way) to appreciate the improvement in performance.

 

8HP is believable

There is so much BS about pipes. As an aircraft engineer, you know how easy it is to do a report proving anything.

My job that doesn't pay had me review 104 exhaust systems. It was very rare that a pipe and jetting/mapping ever exceeded 4 hp gain at top of rev range. Dynos are suspect, but can be used to create a baseline.

It doesn't take an engineer to realize that most hp increase claims are just that, claims.

 

Very true!
It is very discouraging when people take perfectly good data and filter it through rose colored glasses to get a result that they want rather than admit that there there was no appreciable gains. Nobody wins! I currently have to deal with this all of the time in the politics of aviation management. Sometimes I wish I had stayed on the wrenches as there was no agenda there.

I'm surprised that 4hp was all that you saw but I suppose that speaks to the initial quality of the delivered product. They have pretty much sorted it out and reached the optimal compromise for a mass produced machine. To see real gains we need to look at the complete picture. Intake, head, cams, fuel, timing, and then exhaust tuning to all work in harmony at achieving the end goal of more usable HP at the rear wheel. The guys at Dynamo Humm used to have some impressive graphs after they installed the big bore kits and did some head work but Like you say, there are a lot of variables!

Sorry about the verbal diahorea, nobody is chatting!

 

There is no way any VFR drops off that much after 10500. Sure a full system will help maintain HP in the upper RPMs but a 50hp differencen? No way I mean think about it a stock 90 VFR should have 85-90hp at the wheel the drop off up top should only be 5HP or so provided the bike is in top shape so this full hindle system was making 130hp at the wheel? Bottom line is on a VFR you are looking at minimal gaines with a slip on and map maybe 3-5hp if it's a full system maybe 6-8hp but you'll be sacrificing bottom end. Also everyone who says dyno results can be suspect speaks the truth you can get a wide variety of numbers depending on conditions, type of dyno and the operator.