De-Cat Pcv Autotune.

[Volfy]

FYi to calculate real HP the equation is Peak Torque (ft-lbs) x Peak Torque RPM / 5252. So your 95.34ft-lbs x 7200 /5252 = 130.7 Real HP.

I have never seen this methodology used to determine PEAK HP.

The RPM at which peak torque occurs is arbitrary. For an engine like the VFR1200 that has a very flat torque curve extending well above the point of max torque, actual MAX HP occurs much higher in the RPM range. This is typically of most engines. Max HP almost always occurs above max torque in the RPM range. As shown on the graph, at 10K RPM, torque produced is still at 88 ft-lbs (strictly speaking it should be lbs-ft), which is some 92% of max torque. The same equation HP = torque x RPM / 5252 applies at 10K RPM, as it does at 7K, thus the calculated 167HP.

The correction factors I know of as it related to dyno readings apply to normalizing to standard atmospheric pressure at sea level and "standard" temp/RH. Unless the test is conducted on Mt. Everest, the correction factors are not that significant.

[Guest]

I'm sorry but you are quite wrong. The fact that you calculate an enhanced torque level at 130 hp confirms this. I'm on my phone or else I'd explain fully.

[luvtoleanit]

Thanks, at the end of the day, the bike feels fine, and as i have already said, i can't see why Dynojet UK Technicions would use different ways of working the bhp and torque figures out surely the Technicions at Dynojet uk would use the same formula, or whats the point. This is what i hate about Dyno Readings, every body allways has a different view on things, my point was as long as all the VFR's what were ran up at Dynojet UK were worked out with the same formula it must be pretty accurate. Yes i know better still all the VFR's on the same dyno the same day.

These VFR1200's typically dyno around 150 RWHP (SAE). You've completely removed the cat (plan to do the same with some welding), free'd up the silencer, removed OEM restrictions and mapped it. That cat is a big choke in the system so your numbers are right on in my opinion. You brits use DIN, we typically use SAE here in the States and 164 RWHP SAE sounds about right with all your mods. I am jealous and can't wait to get mine where yours is but I'm still recovering from my R1 build which drained the farkle account.

Someone will always bitch when you have something they don't. Enjoy it. You've built a nice bike.

[hvfrdave]

Thanks, at the end of the day, the bike feels fine, and as i have already said, i can't see why Dynojet UK Technicions would use different ways of working the bhp and torque figures out surely the Technicions at Dynojet uk would use the same formula, or whats the point. This is what i hate about Dyno Readings, every body allways has a different view on things, my point was as long as all the VFR's what were ran up at Dynojet UK were worked out with the same formula it must be pretty accurate. Yes i know better still all the VFR's on the same dyno the same day.

These VFR1200's typically dyno around 150 RWHP (SAE). You've completely removed the cat (plan to do the same with some welding), free'd up the silencer, removed OEM restrictions and mapped it. That cat is a big choke in the system so your numbers are right on in my opinion. You brits use DIN, we typically use SAE here in the States and 164 RWHP SAE sounds about right with all your mods. I am jealous and can't wait to get mine where yours is but I'm still recovering from my R1 build which drained the farkle account.

Someone will always bitch when you have something they don't. Enjoy it. You've built a nice bike.

Thankyou, i was starting to think we British were not very welcome on your forum, i am only trying to help. The exhaust system on the VFR 1200 just strangles the engine.

[Guest]

Just to follow up, I've finished work so I'd like to elucidate. I'm not trying to be clever here but I am a retired engineer who started life as a very keen professional mechanic before graduating literally to other disciplines (nuclear engineering).

Horsepower is a mathematically derived figure. It is derived from two values measured on a brake or dynamometer, torque and rpm. Horsepower is the rate of doing torque. You have universally; force, work (force x distance) and power (rate of doing work).

An internal combustion engine produces little or no useful torque at low rpm hence the need for a gearbox. At zero rpm you get no torque (unlike some external combustion engines and electric motors - steam trains don't generally have gearboxes). Maximum torque is at the point when the engine is most efficient. Maximum torque is never in practice at the same rpm as the maximum power, it's always at a lower rpm. Different types of engines have very different relative torque and power positions on the rpm scale.

Power is the product or multiplication of two numbers, Torque and N where N is the rate of revolution. There is also a constant figure involved. With SAE power the units used for torque are Imperial, ft.lbf. For DIN calculations metric units are used. The result is similar but not identical figures where DIN are higher. Correction Factors are also similar but different for the same reasons. Neither is wrong or optimistic, they are just different.

So if we look at multiplying two numbers (and given that rpm on the graph always rises in a linear fashion), if torque is also rising then power rises quite sharply. If torque is constant then again power will rise at a linear rate all the time rpm increases as a constant number multiplied by a increasingly larger number is always increasing. In fact power will increase even when the torque value is falling so long as the product of the two increases. Power will increase with rpm as long as the engine is producing 'useful' torque. When this product or multiple stops increasing then you've reached maximum power.

If you look at any set of torque power curves you will see this. The measured torque goes from nothing, rises and then falls. The power curve peaks after the maximum torque, in the case of the VFR1200 well after at about 3,000 rpm later at the point where torque drops off more than rpm increases.

This maximum power is of course always calculated by multiplying the torque, the revs and the constant. It's the torque (less than maximum), and the rpm at the point at which maximum power occurs.

For example:

Dave's Viffer max power is at approximately 10,000 rpm. Torque at this point is also approx at 88 ft.lbf. (Taken from squinting at the screen - maximum is 95).

Using the SAE formulae for horsepower, (2PiNT)/33,000 when N = 10,000 and T = 88 and Pi = 3.142 gives us:

167.57 horsepower.

That's a SAE calculation btw. And standard VFR1200's usually dyne at 140 to 145 in my experience.

Simples.

I'm aware that brake technology has moved on but I believe that even on a modern inertia brake power is still computed from torque.

By the way, I also received nothing but negatives from this forum when I published my power figures.

[Volfy]

Thanks, hvfrdave, for posting the results and the story. Rear wheel HP or otherwise, it's all more than I would ever make use of on the road anyway. However, it's good fun reading fellow Viffer owners actually taking the effort to go through the mod and dyno. I like the feedback on the improvement on throttle transition and low speed part throttle fueling. To me, arguing the absolute numbers is immaterial. If your dyno guy says yours has the highest output of all the VFRs he had dyno'ed up to that point, that's just a reference point. Whatever his correction factor(s), he surely applied the same for all the dyno runs.

Sanemancured, what you said is the understanding of this engineer as well.

[Guest]

Purely out of interest I did some research and calculated the SAE CF based on the temperature, air pressure and humidity taken from the graph Dave posted above.

The SAE CF is 0.971 (compared to a DIN CF of 1.0) and the SAE hp calculated by DJUK is 167.76

SAE corrected hp works out to 162.9

[crazybrother]

Nice write up fella's... (Bloke's... Mate's...)

I think that I might just have my cat removed too. I have a good friend that's an excellent welder, i'm sure he could do the same.

Dave, did you have to make a jig for the new pipe or just cut out the cat and weld in the new spool?

Thanks.

Just read you post on the Cat removal, very nice! I think that I might do it too.

After looking at your pic's, any idea whats in the chambers on the two outlets that are expanding out?

[hvfrdave]

Nice write up fella's... (Bloke's... Mate's...)

I think that I might just have my cat removed too. I have a good friend that's an excellent welder, i'm sure he could do the same.

Dave, did you have to make a jig for the new pipe or just cut out the cat and weld in the new spool?

Thanks.

Just read you post on the Cat removal, very nice! I think that I might do it too.

After looking at your pic's, any idea whats in the chambers on the two outlets that are expanding out?

You can just cut the cat out either with a very thin cutting disc, or a axesaw, you don't need a jig because if you look at the manifold you can see there are 2 link brackets holding the exhaust manifold pipes in place. As regards to the chambers they are maybe for expansion purposes, or resonating purpose's or both.

A photo of the inside of the cat, and also if you look closely one of the chambers.

[crazybrother]

Yep, that's gotta go!

Free flowing my ass... I've been lied too...

[luvtoleanit]

Yep, that's a choke!!!!!!!!!!!!!!!

[dynajohn]

Great job. Very clean proffesional pipe work. I wonder exactly how much of a restriction the cat is though. Typically modern cats are very efficent. On my 08 Corvette the difference between using cats in the exhaust (with tube headers) was 4 HP at the rear wheels. This is a reduction to 492 RWHP from 496 RWHP. Do the math that is less than 1%. Did you get any dyno readings with auto tune and the cat installed versus the pipe after the cat removed and a full dyno tune??

After seeing your setup I am going to remove the cat this winter just to clean up the exhaust system as much as for any power benefit.

[hvfrdave]

Great job. Very clean proffesional pipe work. I wonder exactly how much of a restriction the cat is though. Typically modern cats are very efficent. On my 08 Corvette the difference between using cats in the exhaust (with tube headers) was 4 HP at the rear wheels. This is a reduction to 492 RWHP from 496 RWHP. Do the math that is less than 1%. Did you get any dyno readings with auto tune and the cat installed versus the pipe after the cat removed and a full dyno tune??

After seeing your setup I am going to remove the cat this winter just to clean up the exhaust system as much as for any power benefit.

Forget the Autotune, that power reading was a tailor made map, to suit the end can, de-cat, and K&N Air filter, set up with the PCV on the dyno, the Autotune is set up to run + or - 10% of the tailor made map, which I have connected to a map switch, so I can run either the map, or the Autotune. The bike was running at 154bhp with the standard manifolds LeoVince end can, K&N Air filter, PCV, i will try and find a map if you wish, but I have done 3 de-cat manifolds now, and they all have a big improvement in BHP & Torque, but more important run a lot smoother at low revs, and a lot more responsive right through the rev range.

[dynajohn]

I already planned on a custom dyno tune. We have an excellent DJ dyno tuning shop locally so that will not be a problem. This is going to be a late fall project because I don't want to have any down time in October. Best time of the year to ride here.

Are you using a ZBomb or another method of getting around the 1st, 2nd gear ECU restrictions?

[hvfrdave]

I already planned on a custom dyno tune. We have an excellent DJ dyno tuning shop locally so that will not be a problem. This is going to be a late fall project because I don't want to have any down time in October. Best time of the year to ride here.

Are you using a ZBomb or another method of getting around the 1st, 2nd gear ECU restrictions?

Yes I am using the ZBomb, and it makes a big difference in 1st & 2nd gear.

[dynajohn]

The exhaust looks good, but I'd check the correction factor your dyno guy is using. Assuming my eyes are not deceiving me peak torque is at 7200rpm, so peak HP is 131hp. With the standard DJ correction factors of 1.1-1.15 that could read anywhere between 144 & 151hp. Your 167 reading indicates a correction factor of 1.28 which is way beyond the DJ norms.

FYi to calculate real HP the equation is Peak Torque (ft-lbs) x Peak Torque RPM / 5252. So your 95.34ft-lbs x 7200 /5252 = 130.7 Real HP.

Dynojet dynamometers do read Torque correctly, but they are a bit liberal with their calculation to get HP (all dynos calculate HP from Torque), they use the magic correction factor above 1.

What are you trying to say here, that peak HP should be calculated using the RPM that peak torque occurs. The equation is correct but it is for calculating HP when you know the torque value at a given RPM, in this case 7200 RPM, not the near 10,000 RPM where the HP peak occurs for this bike.

An engine's torque is determined by the percentage the cylinders are filled at a given RPM. The greater the cylinder fill is, the greater the torque. Peak torque is reached when an engine runs out of the ability to further increase the cylinder fill. An engine can continue to make more HP even when torque is falling as long as RPM is increasing faster than torque is falling. So if maximum torque is the point of maximum cylinder fill, then maximum HP is the point where torque is falling off faster than RPM is increasing.

[dynajohn]

Dave, I decided to start on this project a little earlier than originally planned based on your experience & excellent write up. Yesterday I pulled all the body work & blocked off the airbox entrance to the pair system. Installed the DJ plugs on the stock 02 sensor plugs (a real PITA job). Apparently Honda doesn't think the 02 sensors will ever have to be replaced. Next job is actually installing the PC 5 and autotune module along with a DJ quick shifter.

I was really surprised when i got a look at the stock air filter. I can see why you replaced it with a K&N filter Dave. The filter area is actually larger than on my ZX14 but between the screen & the perforated metal plate on the outlet side of the filter it looks to be much less efficient than the smaller stock ZX14 filter.

Question on the exhaust system removal?? the manual says the radiator has to be removed but it looks to me like there is enough give if the lower radiator mount bolts are removed to get the pipes off. Of course on the rear cylinders the pipes come apart at the two slip connectors. Did you pull the radiator?

After I get the pipes off and delivered to my friend who fabricates custom car exhausts I am going to pull the airbox & throttle bodys to get a look at the intake ports. I want to see how well Honda matched up the rubber connectors to the TB's and intake ports. If there is any mismatch at the rubber connectors this can be corrected at this point. I would love to do mild porting work on this motor and mill the heads to get the compression up a half point but that requires removing the engine to get the front head off. That is further than I want to go considering I have a 2012 ZX14R whose performance is far beyond anything i can reasonably achieve with the VFR12. If i can match what Dave has achieved I will be satisfied.

[hvfrdave]

Dave, I decided to start on this project a little earlier than originally planned based on your experience & excellent write up. Yesterday I pulled all the body work & blocked off the airbox entrance to the pair system. Installed the DJ plugs on the stock 02 sensor plugs (a real PITA job). Apparently Honda doesn't think the 02 sensors will ever have to be replaced. Next job is actually installing the PC 5 and autotune module along with a DJ quick shifter.

I was really surprised when i got a look at the stock air filter. I can see why you replaced it with a K&N filter Dave. The filter area is actually larger than on my ZX14 but between the screen & the perforated metal plate on the outlet side of the filter it looks to be much less efficient than the smaller stock ZX14 filter.

Question on the exhaust system removal?? the manual says the radiator has to be removed but it looks to me like there is enough give if the lower radiator mount bolts are removed to get the pipes off. Of course on the rear cylinders the pipes come apart at the two slip connectors. Did you pull the radiator?

After I get the pipes off and delivered to my friend who fabricates custom car exhausts I am going to pull the airbox & throttle bodys to get a look at the intake ports. I want to see how well Honda matched up the rubber connectors to the TB's and intake ports. If there is any mismatch at the rubber connectors this can be corrected at this point. I would love to do mild porting work on this motor and mill the heads to get the compression up a half point but that requires removing the engine to get the front head off. That is further than I want to go considering I have a 2012 ZX14R whose performance is far beyond anything i can reasonably achieve with the VFR12. If i can match what Dave has achieved I will be satisfied.

Hi bud, you are correct, there is no need to take of the radiator, remove the 2 bolts from the radiator fan housing, one on each side, then remove the horn, also the bolt holding the top of the radiator near the horn, then undo the the brake flexy bolt just above top of radiator. Now you need to slide the bottom of the radiator forward, then slide the top of the radiator across to the R/Hand side of the bike, [that's if you were sat on it] it's a little tricky, I used a screwdriver to ease the r/h top bush to release the radiator, so now you can hold the radiator forward for access to the front exhaust header nuts, hope this helps, Dave.

[dynajohn]

Yes it does help. I had antisipated some of what you described but not all the steps. Really helps to follow where someone else has already been.

By the way have you run across a oil additive called Petron over there. I believe it is a European product that is distributed by Brock Davidson in the USA. We used it on a project street/drag race build on my 2012 ZX14R I did with Brock Davidson Performance. It is used by a lot of race teams here and I have used it in my race & street bikes since 2006. No hype we can measure the results on the dyno.

Thanks for the help, John

[dynajohn]

Dave, I found something interesting when I removed the pipes. The header design has changed (probably in 2012). You're 2010 pipes have both the 02 sensors located just ahead of the cat and both pipes feeding the cat are the same uniform diameter based on your posted pictures. The 02 sensor for the rear cylinders on my 2013 is re-located about a foot back toward the rear and between the small resonator and the collector for the rear cylinders. The pipe shape in the U bend for the rear cylinders just ahead of where it connects to the cat has been re-shaped. The rear pipe widens and flattens in the u bend just ahead of the connection into the cat. The internal volume of the rear pipe increases in the u bend. The front cylinders pipe appears to be the same as the 2010. Obviously Honda did some exhaust re-tuning here.

Fortunately I have a connection with Chad Wells the service manager at Commonwealth Motorcycles (Ducati, MV Agusta, Triumph) here in Louisville. This is a dealership with a real passion for high performance motorcycles. Chad is a really talented constructor/tuner with a passion for all things high performance & has some very talented connections in the custom exhaust side of the business he uses for high end Ducati projects. He is using one of these relationships to get a custom stainless 2 into 1 merge collector fabricated and installed in place of the stock cat. If any of you guys get Motorcyclist Magazine they featured a turbocharged Ducati Diavel Chad built in last months issue.

Chad will also be doing the dyno tuning on Commenwealth's load control DynoJet 250 when I get everything back together. They have a nice custom build dyno room and Chad does a lot of custom tuning. I plan on everything coming together to finish this project sometime in mid November. Hope to be able to celebrate equalling what you have achieved with your VFR .

Thanks again for the help & encouragement Dave.

[hvfrdave]

Dave, I found something interesting when I removed the pipes. The header design has changed (probably in 2012). You're 2010 pipes have both the 02 sensors located just ahead of the cat and both pipes feeding the cat are the same uniform diameter based on your posted pictures. The 02 sensor for the rear cylinders on my 2013 is re-located about a foot back toward the rear and between the small resonator and the collector for the rear cylinders. The pipe shape in the U bend for the rear cylinders just ahead of where it connects to the cat has been re-shaped. The rear pipe widens and flattens in the u bend just ahead of the connection into the cat. The internal volume of the rear pipe increases in the u bend. The front cylinders pipe appears to be the same as the 2010. Obviously Honda did some exhaust re-tuning here.

Fortunately I have a connection with Chad Wells the service manager at Commonwealth Motorcycles (Ducati, MV Agusta, Triumph) here in Louisville. This is a dealership with a real passion for high performance motorcycles. Chad is a really talented constructor/tuner with a passion for all things high performance & has some very talented connections in the custom exhaust side of the business he uses for high end Ducati projects. He is using one of these relationships to get a custom stainless 2 into 1 merge collector fabricated and installed in place of the stock cat. If any of you guys get Motorcyclist Magazine they featured a turbocharged Ducati Diavel Chad built in last months issue.

Chad will also be doing the dyno tuning on Commenwealth's load control DynoJet 250 when I get everything back together. They have a nice custom build dyno room and Chad does a lot of custom tuning. I plan on everything coming together to finish this project sometime in mid November. Hope to be able to celebrate equalling what you have achieved with your VFR .

Thanks again for the help & encouragement Dave.

Hi John, looking forward to see your results. :smile2: My next stage over the winter, is to sort out the suspension, Ohlins front fork springs, and a re-valve, with some top quality fork oil. Ohlins or Nitron rear shock unit, with Hydraulic spring pre load adjuster, compression and rebound adjustment.

[dynajohn]

This is taking a lot longer than I antisipated. Got the pipes back and installed. Fabricator did a beautiful job installing a 2/1 merge collector in place of the cat. I went a slightly different route than Dave in that I used a 45 degree weld fitting for the wide band sensor which enabled me to move it forward a couple of inches. I didn't like how much the 90 degree bung made the sensor head protrude into the collector. Small detail but I like the way it came out. Got the PC 5, auto tune module & quick shifter mounted & wired. The hardest part of the wiring was routing the wideband sensor harness up and behind the frame on the left side where it can't be seen (compleatly hidden). Blocked the pair valve outlet at the air box and installed the K&N filter. Final change was installing a set of Phillips high intensity headlight bulbs. Still waiting on the Akrapovic slip on & then the fun part begins (road & dyno tuning).

Don't know if I will do anything to the stock suspension. The bike seems to handle fine at the pace I ride these days on public roads.

[dynajohn]

Delivered the bike to Chad at Commonwealth today for dyno tuning. Should have some dyno data in a few days. Only change from my original plan was I cancelled the order for the Akrapovic and substituted a Leo Vinci pipe. Love Akrapovic but they could not give me a delivery date after 6 weeks of being on back order. After tuning we are going to do 2nd gear full throttle pulls with & without the Zbomb to see how the data matches up to what Bazzaz posted.

John

[dynajohn]

OK I got the dyno results today. 158.76 HP and 90.75 ft/lbs torque. These are SAE corrected figures. Very impressed with the torque curve. Torque was above 80 ft/lbs from 5,200 to 10,200 RPM's. The above readings were with the DB killer removed from the Leo Vinci muffler. With the DB killer installed the max HP was 156.36 with max torque at 90.03 ft/lbs. The hp & TQ curves with and without the DB killer installed are virtually the same until the RPM gets above 8,700 RPM where the run without the DB killer pulls slight away. I recieved a 2 GB file with all dyno runs in both graph & spreadsheet format. I personally prefer the spreadsheet format because it gives far more detail. The spreadsheets list run time, RPM in 250 RPM increments, HP, TQ, and AF ratio. The final two runs were with & without the Z Bomb installed in 2nd gear. They confirm that the 2013 VFR is still neutered in the first two gears. there is a 18 HP difference at 5,200 RPM's.

[luvtoleanit]

. there is a 18 HP difference at 5,200 RPM's.

F'in wow!!!!