Hardtop Brian

I never noticed this until I put the go pro on my gauges. The 2-3 limiter bump I think will be taken care of once I get the speedometer calibrated for the 3.73 I have from the 3.42. The thing I'm slightly concerned with is the rpm's that I'm crossing the finish line in. I'm seeing 6100-ish. After calculating converter slip (or efficiency) with the 96% efficiency of the ss4000 (I found this in a couple spots on the internet), it says I should be at 5700-5800 rpm crossing the line with 3.73 and 26.4" (83" rollout/circumference) tire, but I'm showing 11% "slip".

Is this actually the converter or is 3rd slipping a little? Or is it something else? If a trans issue, would the transgo hd2 kit "fix" it for a little while?

Trans is a 3 year old stock rebuild with 5k miles on it.


**I also posted this in Drag Tech. Apologies if that was incorrent.

Jays_SSZ28

iTrader: (2)

If third was slipping my opinion tells me it would look like a cut-loose. The rpm would go up and mph would go down.
The only thing I see wrong is a lean reading on the wideband.

I really don't think you can calculate converter slip if you have it tuned for 3.42's and you're running 3.73's. It has to be tuned for the gear thats in it, otherwise you're guessing at mph and your shift points are wrong, etc

I'm used to just running a car, once you get into electronics and calculating efficiency, etc, you're no longer enjoying the sport. It just creates more questions and looking for problems that don't exist. JMO

Hardtop Brian

This was first time at the track after I installed the gauges 2 days prior. I noticed it lean at WOT also, but it has likely been doing that the past 2 years on this tune. The other thing you can't see is the the fuel pressure drop from 58 to 50.2 at launch and then climbs to 53 at the end of the track. I have a racetronix pump with hotwire on the shelf and I wanted some baseline numbers before I swapped it in to see how it changes the fuel pressure. So hopefully that will fix the pressure drop and the lean condition.

rpm's are rpm's regardless of rear end. I'm comparing the tach to when I cross the finish line and the trap speed, not what is showing on the speedometer (120+). I guess there is some error in there since trap speed is the average mph over the last 60'. But like you said, maybe I'm looking into it too hard and making something of nothing