CSC #1 2016 – IMI Motorsports – Discussion

@Greg Welch wrote:

I’d baseline it with a 3.55 ratio and maybe 12-13 on pressures. Most likely remove any supplemental seat struts you had on it for the Duros. Easy to test just by removing the top bolt. Most Duro guys will end up overstuck up at IMI on Reds.

Awesome, thank you sir! I totally forgot about the ratio. lol 12-13 pressures, I will for sure give that a try. I don’t actually run any seat struts other than the two used to hold up the seat. May have to try that out with the Duro’s!

@Rodney Ebersole wrote:

My 2 cents when talking about float ht. and needle pin positions.
The needle has 5 positions from the top towards the bottom or pointy end , the top slot is the leanest slot and the bottom slot is the richest.
Often it is defined as pin 1 as the leanest slot or pin 5 as the richest slot.
To say the “last” position isn’t a good description as that could be the top or bottom slot.

The float height is a measurement of the float with the carb up side down.
A higher measurement causes a lower/leaner fuel level in the bowl when running.
The typical range for float ht. measurements is .840 to .900 inches.
It can be confusing as a person will say they raised their float height when really changing the float height measurement to a higher amount when up side down is actually lowering the level of the floats when it is running or right side up. LOL
A .200 change in height would create a problem. I suspect Jdavis-403 made a .020 change instead of a .200 change as mentioned in his earlier post.

The .200 change wasn’t in height it was in lap times. 😉 Sorry I should have been more clear there. Thank you for clearing up communication in regards to how to explain the float height measurements. I didn’t adjust the float height by .200 that was my lap time change after changing my float height. I mentioned in that same post that I couldn’t remember/find my notes where I made the change so I couldn’t give the exact amount. I will be cleaning my kart tonight and may be able to get the adjustments tonight. In regards to the pin I am in the #1 spot. Lean as you can make it. 🙂

@Jeff Welch wrote:

I have no direct experience with Reds but if you’re doing something like running the rear end super narrow to get grip with Duros, you’ll likely want to bump back out to the 54.5-55″ that most manufacturers recommend when you switch to Reds. They have enough grip to make the chassis actually work as designed.

Great recommendation. I will have to give that a try.

Based on my Chassis (Margay – Brava 4.15) the setup guide recommends only 1″ difference compared to the softer tire vs harder tire. Granted, they also recommend a harder axle for the softer tire. I will send them an email to see if they recommend anything different for different tires as they did recommend +4mm camber for the fronts on Duros. Once I receive a reply I will reply back.

On a side note: I wasn’t able to check my float height tonight. I was busy on the front end. Seems that wall hit at the CKT race messed up the front end and took some time fixing that and also cleaning up the whole kart. Tomorrow I plan on taking the engine down and performing maintenance on the drive area. I will check at that time.