Dyno sheet - Harley Davidson Forums: Harley Davidson Motorcycle Forum

Autotec · 08-08-2009, 01:21 AM

So I was going through the paperwork that came with my bike, and I came across the dyno sheets. I was also looking through the paperwork that came with the S&S Super Stock kit and saw something that cought my eye. The paperwork shows this kit should make around 90hp, alolng with 90 lbs ft of torque. The dyno sheet shows 70hp, and 84 ibs ft of torque.

The bike is 80ci, S&S Super Stock heads, 10-1 pistons, S&S 561 cam, S&S "E" carb, V&H longshots. Stock ignition

Does this seem about right? I know the dyno numbers are at the wheel, and the numbers in the S&S paperwork are probably at the crank.

The torque seems right, but the hp seems low.

Thanks, Justin

**Kainam** · 08-08-2009, 01:43 AM

Probably the difference between the exhaust they used and the V&H longshots is enough to cause the discrepancy.

It doesn't look like they had the A/F analyzer hooked up, that dip at 2300 could be an accelerator pump that needs adjusting or midrange jet needing adjusting.

Autotec · 08-08-2009, 01:51 AM

I was told that the pipes on my bike were holding it back from the prior owner. I might have to start looking at a new set.

But they sound so good.

**Kainam** · 08-08-2009, 01:54 AM

Yup... thats all part of the "exhaust trilogy" that we all have to balance...

1) Performance
2) Looks or Sound
3) Price

Autotec · 08-08-2009, 01:57 AM

Mmmmm. That would explain (maybe) the pinging I get on the hwy. Maybe I'll try to richen it up tomorrow. Plugs look good though.

**Kainam** · 08-08-2009, 02:15 AM

Quote:

Originally Posted by Autotec

Mmmmm. That would explain (maybe) the pinging I get on the hwy. Maybe I'll try to richen it up tomorrow. Plugs look good though.

This has me curious....

What octane are you running? Have you tried gas from a different station?
What spark plugs are you running?

Just wondering cause you say the plugs look ok...

Autotec · 08-08-2009, 02:26 AM

I run 93 octane, tried a number of stations. I always ended up with the same result.

I'll have to pull the plugs tomorrow to check the number. I'm pretty sure they are the standard plugs.

I installed a SE ignition module earlier in the year with bad results. It would ping very, very bad at part throttle. Full throttle was great though. I kinda assumed it was a lean condition, but I never got around to checking it. I just installed the stock module after 20 miles and the ping went mostly away.

**Kainam** · 08-08-2009, 02:37 AM

Interesting....

This is starting to sound more like a timing issue rather than a pre-detonation (pinging) issue.

Unfortunately you can not change the timing on the stock Evo ignition modules...
And what you effectively did was retard the timing some when you went from the SE ignition then back to stock.

I'd be interested in seeing if Dave agrees before you sink some money into an adjustable ignition module.

Autotec · 08-08-2009, 02:44 AM

The SE module I have has multiple curves. I played around with all of the curves, it never made a difference. Could it be a problem with the VOES?

Battery is almost dead on the laptop, I'll check the plugs again tomorrow and post the plug #.

Thanks for the advice tonight. I'll have more info in the morning.

Justin

**Kainam** · 08-08-2009, 03:08 AM

Yes. Basically on Evo motors, there are 2 ignition curves. The VOES switch tells the ignition module which ignition curve to use.

Under acceleration, or any high vacuum conditions, the VOES switch closes (grounding out the VOES input on the ignition module) which tells the ignition module to use the advanced curve. When it is open, the ignition module uses the retarded curve, making start up easier.