Dyno Comparison of Cobra Tri-Ovals and V&H slip-ons

[RACNRAY]

I hope this helps...

Here is a comparison of the H.P./torque increases over stock mufflers of those slip-ons performed on two totally stock Vaquero's on my dyno.


@1500 RPM......COBRA +1.2 HP/+4.4 PNDS ......V&H+1.3 HP/+4.5 PNDS

@2000 RPM......COBRA +.6 HP/+1.4 PNDS...........V&H +.7 HP/+1.6 PNDS

@2500 RPM......COBRA +2.1 HP/+4.5 PNDS...........V&H+2.2 HP/4.7 PNDS

@3000 RPM......COBRA +2.8 HP/+5 PNDS............V&H+3.7 HP/+6.4 PNDS

@3500 RPM......COBRA+3.2 HP/+4.7 PNDS..........V&H+4.5 HP/+6.7 PNDS

@4000 RPM......COBRA +2.2 HP/+2.8 PNDS..........V&H+4.4 HP/+5.7 PNDS

@4500 RPM......COBRA +2.4 HP/+2.9 PNDS ..........V&H+4.5 HP/+5.2 PNDS

@5000 RPM......COBRA +2.4 HP/+2.5 PNDS ..........V&H+4 HP/+4.2 PNDS

@5500 RPM ......COBRA 2.6 HP/+2.4 PNDS............V&H+2.6 HP/+2.4 PNDS

The Tri ovals are a far more restrictive slip-on as they do not have a straight thru core as does the V&H slip-ons. The V&H's are deffinately louder with more of a "bark", the Tri ovals are very mellow in comparison.

We just modified a Vaquero with the Tri-ovals, a BAK and PCV, we did not get the gains in peak power as I have seen due to the Tri-ovals restrictive design. My modified Cobra round slip-ons I had on last year with straight-thru baffles to replace the restrictive baffles that came with those slip-ons made more power thru the whole rpm range, these big twins need to BREATH!!

Bottom line, if you want an increase in power, both brands will do just that. It then comes down to cost, appearance, sound levels and how important the actual power increase over stock that is provided by each slip-on.

RACNRAY

[redjay]

Are the mufflers on the 2009 and 2010 Voyagers more restrictive than the Cobras ?
The mufflers on the 2011 Voyagers are quieter, are they therefore more constrictive than the 2009/2010 models ?

[Monkeyman]

I asked this in another thread (and can't find the thread) but are those dyno increases cumulative?

[RACNRAY]

Originally Posted by Monkeyman

I asked this in another thread (and can't find the thread) but are those dyno increases cumulative?

My answer copied and pasted from that thread...

"No, they are not cumulative. The numbers represent the actual gain over stock at that exact rpm.

What the dyno does not measure is the improvement in throttle response WE FEEL as a result of the increae in power and torque."

RACNRAY

[Monkeyman]

So the most you will gain (in the numbers) with V&H slip ons (on an otherwise stock bike) is about 4 1/2 hp? How did you gain the other 20 or so on your bike. Just in the fuel processor and intake? I understand the seat of the pants thing. If it feels fast, I'm happier even if it's still a dog. (And to be honest, the stock 67 or so hp on a 900# bike isn't much.)

[RACNRAY]

Originally Posted by Monkeyman

So the most you will gain (in the numbers) with V&H slip ons (on an otherwise stock bike) is about 4 1/2 hp? How did you gain the other 20 or so on your bike. Just in the fuel processor and intake? I understand the seat of the pants thing. If it feels fast, I'm happier even if it's still a dog. (And to be honest, the stock 67 or so hp on a 900# bike isn't much.)

There was NO fuel injection tuning performed on either of these Vaquero's for this comparison, so there will be a further gain in power if the skoots were tuned for the proper a/f ratio.

The gains on my skoot are the result of a few mods.

I fabricated my own BAK which is of VERY different design from all the others I have seen. The 1700's are severly strangled by the stock intake.

Second, I HIGHLY modified my Vance & Hines 2-1 full exhaust. Lotsa time went into the re-design of the baffle.

Third, custom mapping for the proper air/fuel ratio with ignition timing alterations on my dyno.

RACNRAY

[Bsharris2011]

Ray,
Thanks for the great info and all you have provided here in these forums. I sent you the link to the Dobeck TFI, not sure if you have had a chance to look at it or not. I looked at it a bit more and it doesn't seem to affect ignition, albeit a simpler unit. I still hav,en't pulled the trigeer on the pcv yet but am curious, when you setup these units, do use the multiple tables for each gear? Or just the one table for fuel and one for ignition? Also, as just some insight, I figured the ignition table is adjusted in degrees and the basic map from Dynojet for exhaust modifications has a "4" in the upper rpm/upper throttle region. I am assuming this modifies the existing values by 4 degrees. However, what do the numbers in the fuel table refer to? Percentages? The same map has values ranging from 0 up to 20 in the various regions. I know these are over and above whatever the stock ecu is doing, but wasn't sure if these represent percentages or ??. Lastly, do you know what the fuel "pressure" tables are for? Thanks again for your help and info with everything. I ordered the BAK from Chuckster as you had recommended and expect the modified grips from you any day. I just have to decide now on tuner and pipes. I am leaning towards the V&H only because I have had them on my 1600 classic (longshots) and my Ultra classic (ovals) and the ultra sounded a bit more tame than the classic. It was very loud and I am thinking that the V&H on the Nomad would sound similar to my Ultra that had the ovals. Plus they are about $60 cheaper. Although, I do like the way the Cobra tri-ovals look on the end, that is the main reason I am tossed between them.