Dyno Run, V&H straight shots vs. Screamin' Eagles

[ReddTigger]

at 50 or 60 Mph in 5th i'm at 2500 rpm.
in 4th I'm at 32-3300..

The bike runs great, idles great and has lots of power.

I'll worry about it more when I start putting in cams, ignition and carb.

[rfranz1952]

I would point out that it is very difficult to compare two dyno runs taken at different times and on different dynos with different operators to any degree of accuracy.

One difference between the dyno's here is that the one done on the Vance and Hines uses a "Standard" correction factor while the dyno on the SE pipes uses an SAE correction factor. A standard correction returns a higher HP number--perhaps 2 - 5 HP difference--than does a dyno run done with an SAE correction. Thus, to make them comparable in any sense, we need to subtract somewhere between 2 - 5 HP from the Vance and Hines results. Absent other differences in the testing, the V&H results would likely have been somewhere between 62 and 66HP on an SAE corrected run, compared to the SE result of 71.3 HP. So, there could be a difference of nearly 10HP between the products, and similar differences in torque results, with the SE slash cuts on top. We can't say for sure, though.

I would also point out that the scales on the graphs--both vertical (HP and Torque) and horizontal (rpm) are different. This doesn't affect the numeric results, but it does change the way the curves appear to us, and we must be careful in interpreting that.

Attached is a link to a site discussing dyno results and the pitfalls in using them as a standard of comparison.

http://www.bishopsperformance.com/dynoinfo.htm

While I am not saying that this post was intended to promote one product over another, when we see dyno results used by vendors to promote a prodct, they must be taken with a grain of salt, as there can be very significant differences that are not attributable to the product. Let the buyer beware!

Happy Father's day everyone.

[ReddTigger]

Originally Posted by rfranz1952

I would point out that it is very difficult to compare two dyno runs taken at different times and on different dynos with different operators to any degree of accuracy.

One difference between the dyno's here is that the one done on the Vance and Hines uses a "Standard" correction factor while the dyno on the SE pipes uses an SAE correction factor. A standard correction returns a higher HP number--perhaps 2 - 5 HP difference--than does a dyno run done with an SAE correction. Thus, to make them comparable in any sense, we need to subtract somewhere between 2 - 5 HP from the Vance and Hines results. Absent other differences in the testing, the V&H results would likely have been somewhere between 62 and 66HP on an SAE corrected run, compared to the SE result of 71.3 HP. So, there could be a difference of nearly 10HP between the products, and similar differences in torque results, with the SE slash cuts on top. We can't say for sure, though.

I would also point out that the scales on the graphs--both vertical (HP and Torque) and horizontal (rpm) are different. This doesn't affect the numeric results, but it does change the way the curves appear to us, and we must be careful in interpreting that.

Attached is a link to a site discussing dyno results and the pitfalls in using them as a standard of comparison.

http://www.bishopsperformance.com/dynoinfo.htm

While I am not saying that this post was intended to promote one product over another, when we see dyno results used by vendors to promote a prodct, they must be taken with a grain of salt, as there can be very significant differences that are not attributable to the product. Let the buyer beware!

Happy Father's day everyone.

But also the original dyno was done on a dynojet 150 vs a dynojet 250i..

I have more faith in the second set of numbers then the 1st. and seat of the pants it does feel like it pulls better as well..

[rottenralph]

I think you need cams to take advantage of all the money you spent. I have had n8's with 72/72 with stock heads and n8's so you might want to consider a cam. I did hae the thunderheader at that time. Aestheics is important and the main question here is are you happy with your power. If so, keep the pipes you like to look at best. I paid 230 for my 536 cams and that is a relatively easy project with some pretty substantial potential results.

If you want to feel the power where you want it, get a supertrapp. You add low end torque by reducing discs. The polished supertrapp is quite nice also. I have had the stainless brushed as well and the polished looks a lot better if you ask me. I have heatshields this time as well so the pipes don't discolor.

[rfranz1952]

Originally Posted by ReddTigger

But also the original dyno was done on a dynojet 150 vs a dynojet 250i..

I have more faith in the second set of numbers then the 1st. and seat of the pants it does feel like it pulls better as well..

Yet another difference!

And I agree that "seat of the pants" is the ultimate test, no matter what the machine says!

[TnG]

Originally Posted by rfranz1952

I would point out that it is very difficult to compare two dyno runs taken at different times and on different dynos with different operators to any degree of accuracy.

One difference between the dyno's here is that the one done on the Vance and Hines uses a "Standard" correction factor while the dyno on the SE pipes uses an SAE correction factor. A standard correction returns a higher HP number--perhaps 2 - 5 HP difference--than does a dyno run done with an SAE correction. Thus, to make them comparable in any sense, we need to subtract somewhere between 2 - 5 HP from the Vance and Hines results. Absent other differences in the testing, the V&H results would likely have been somewhere between 62 and 66HP on an SAE corrected run, compared to the SE result of 71.3 HP. So, there could be a difference of nearly 10HP between the products, and similar differences in torque results, with the SE slash cuts on top. We can't say for sure, though.

I would also point out that the scales on the graphs--both vertical (HP and Torque) and horizontal (rpm) are different. This doesn't affect the numeric results, but it does change the way the curves appear to us, and we must be careful in interpreting that.

Attached is a link to a site discussing dyno results and the pitfalls in using them as a standard of comparison.

http://www.bishopsperformance.com/dynoinfo.htm

While I am not saying that this post was intended to promote one product over another, when we see dyno results used by vendors to promote a prodct, they must be taken with a grain of salt, as there can be very significant differences that are not attributable to the product. Let the buyer beware!

Happy Father's day everyone.

Wow, that link had some amazing info in it. Thanks for the post!

[ReddTigger]

Originally Posted by rottenralph

I think you need cams to take advantage of all the money you spent. I have had n8's with 72/72 with stock heads and n8's so you might want to consider a cam. I did hae the thunderheader at that time. Aestheics is important and the main question here is are you happy with your power. If so, keep the pipes you like to look at best. I paid 230 for my 536 cams and that is a relatively easy project with some pretty substantial potential results.

If you want to feel the power where you want it, get a supertrapp. You add low end torque by reducing discs. The polished supertrapp is quite nice also. I have had the stainless brushed as well and the polished looks a lot better if you ask me. I have heatshields this time as well so the pipes don't discolor.

I think I am going to go with the n4's as the 536's put the power curve above the area I like to ride in. I do a lot of twisty riding in the back roads of long island and state roads in pa, nj, and upstate ny. I'll give up a couple of HP for the usability and lower powerband.

and you're right, I know there are lots of pipes that can make more power, I am planning on going with a 2-1 when I figure out which one I want.

[misterT]

It looks to me like the SE pipes are your best performer they start out with over 65 ft/lbs of torque the V&H pipe has only 55. Horsepower appears to be about equal over nearly the whole rpm range though the SE tops out more and the V&H only having 2 ft/lbs of torque more between 4000 and 4500 rpms. Sorry I am not and never will be a fan of Vance & HInes pipes imho they are mediocre at best.

[ReddTigger]

Originally Posted by misterT

It looks to me like the SE pipes are your best performer they start out with over 65 ft/lbs of torque the V&H pipe has only 55. Horsepower appears to be about equal over nearly the whole rpm range though the SE tops out more and the V&H only having 2 ft/lbs of torque more between 4000 and 4500 rpms. Sorry I am not and never will be a fan of Vance & HInes pipes imho they are mediocre at best.

You're right, but I'm glad I finally got rid of that Crossover tube. I know it's a better performer, but I like the way the V&H look over the SE's.. (as I can see more of my motor, and makes any carb adjustments much easier)

however, the V&H do provide about 10 more HP at the lower RPM's and the bike does feel more responsive, with the way I ride.

Eventually I will figure out which is the absolute best combination for my riding style and go that route..

[Quay]

Originally Posted by ReddTigger

and you're right, I know there are lots of pipes that can make more power, I am planning on going with a 2-1 when I figure out which one I want.

Don't overlook the D&D Fatcat. It has been nailing some pretty impressive numbers low down in the powerband, though it appears to soften above 6,000 rpm.