RPM Drop Analysis

R

Ragnar

Member
What are the basic adjustments that can be applied to reduce rpm drop in the corners?

We ran a track this weekend (and won several races) where we were flat-footed the whole lap with no trail braking. Classes were adult so not plate stuff. On average we dropped 700-900 rpm's. When I play back the lap on the track map on Mychron 5 most of the drop occurs from corner entry to just past the apex.

The MPH reading on the playback confirms the kart is slowing down as well so there is real speed to be gained if we can reduce the drop and ultimately drop teeth on the rear.

The steering wheel was neutral the whole lap so no rpm scrub from a bad handling kart. The track is about 630 in the racing line and we were on a 14 driver all night.
 
Ragnar said:
What are the basic adjustments that can be applied to reduce rpm drop in the corners?

We ran a track this weekend (and won several races) where we were flat-footed the whole lap with no trail braking. Classes were adult so not plate stuff. On average we dropped 700-900 rpm's. When I play back the lap on the track map on Mychron 5 most of the drop occurs from corner entry to just past the apex.

The MPH reading on the playback confirms the kart is slowing down as well so there is real speed to be gained if we can reduce the drop and ultimately drop teeth on the rear.

The steering wheel was neutral the whole lap so no rpm scrub from a bad handling kart. The track is about 630 in the racing line and we were on a 14 driver all night.
Click to expand...
I look at RPM drop every time we come off the track. I think it's important to know your base line but I wouldn't get too caught up with it if you are winning. I chased this for a while and concluded that driving style plays a big part in it. I would drop 900 RPM's while others were only dropping 500. However, I was .1-.2 tenths per lap faster than the guy dropping 400 less RPM's.

I hear exactly what you're saying about reducing the RPM drop and losing a tooth or 2 on the rear gear. I thought the same thing. My experience did not yield the results I was hoping for. It takes more discipline than I could find to change my driving style to achieve any positive gains.

If I were in your situation and wanted to experiment, I'd drop a minimum of 2 and probably 3 or even 4 teeth off of the driver. For the rear gear run a slightly smaller ratio than what you had with the 14 driver.
 
Ragnar said:
What are the basic adjustments that can be applied to reduce rpm drop in the corners?

We ran a track this weekend (and won several races) where we were flat-footed the whole lap with no trail braking. Classes were adult so not plate stuff. On average we dropped 700-900 rpm's. When I play back the lap on the track map on Mychron 5 most of the drop occurs from corner entry to just past the apex.

The MPH reading on the playback confirms the kart is slowing down as well so there is real speed to be gained if we can reduce the drop and ultimately drop teeth on the rear.

The steering wheel was neutral the whole lap so no rpm scrub from a bad handling kart. The track is about 630 in the racing line and we were on a 14 driver all night.
Click to expand...
"Loose is fast, and on the edge of out of control."
Harry Hogg
(Days of Thunder)

Because you say steering was neutral, I'm thinking slightly snug, which chews a little speed, even though it looks and feels good.

A little more transfer to the rr on entry and middle.
 
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