So we ran a special front bar this weekend. Typically we don’t run the bar but for this track we felt it needed this particular bar to work best. Prototype stuff…
In hindsight I think for myself I should’ve maybe tried to work without this bar. Not to discredit anything the team worked on or tested, it clearly worked well on the other kart. But for my particular style maybe it wasn’t the optimal choice. I can’t thank the Prodigy guys enough for all the testing they did, the data they gathered, and the support they provided, not only this event but all year. Chris and the guys have been great to work with. Professional, organized, timely, prepared. And I didn’t necessarily want to force a bunch of work on anyone to swap frames for the final but they suggested it and were happy to thrash with me to get some answers.
Same! Alonso is my guy so I always say if he can do it 40+ then shouldn’t I be able to at least hang in a little go-kart race at 33? And Fore too. And actually I felt really good physically which was a surprise because I’ve had weekends at Trackhouse in the past where I was totally gassed at the physical demands of the track. I tore up my ribs there, I strained my back there… but this was more grip than I had ever experienced at this track and I felt completely fine all weekend. I did one week of neck work to prepare and I guess the dad strength kicked in too. Was pretty good all weekend.
So when you say the front end is giving up. It would just tend to understeer over a race?
What else do you have to play with? Extra holes on the steering shaft? Ackermann on the stub axles?
Maybe low rear, mid/high front ride height? To get rid of some rake?
And same age as you. I think the only thing separating me from the young guys is some extra self preservation and the crash damage comes out of my own wallet now. I’m trying really hard to cut weight and being able to run Senior KA at Supernats or a random series next year. 390lb or so Masters weight in the KA sounds rough.
Lowering the rear makes it jack less and sets the rear wheel down earlier. High front is something I tried a times throughout the weekend and it helped at times but never really gave me what I needed.
I had no more holes to put more steering rate in, but I could’ve added Ackermann on the spindles. Again, focused on adjustments I knew best to find a direction before playing with more in-depth things like Ackermann. I tried almost every adjustment on the kart except for a few because I didn’t have enough sessions.
Copy that. I think it does more than just effect the rate of lift. To me it’s a balance shift as well. Seems to take “grip” away from the rear by lowering it. Helps correct some understeer from mid to exit. I think it does lift less, but you carry the inside rear for longer. But you’d know better than me lol.
But I feel ya. Ride height changes at the rear during a race day tend to suck. Especially if your running a handful of seat struts. You can only make so many changes and I try to only do one or two at a time.
If you have a flat OTK bar sitting around I’d be curious if you can try it for a practice day. Run it flat for a couple laps, pull off, flip it vertical, and send it again. Might help rule out if your prototype bar was doing what you wanted it to.
Also on Ackermann. If you are your only option is taking some out I would think it would just make the problem worse. You would have less jacking per steering angle so more of the rears in contact with the ground pushing the fronts. So in my head you would want to add some. Looks like you only have the two options if this picture I found is accurate. Sorry for the wall of text.
Side note. Are the Prodigy guys now running the BestKart instead of the Maranellos? I’ve got a work trip back in Charlotte in a couple months and trying to setup an arrive and drive for a club day.
Prodigy has been Maranello but are looking to add the BestKart. They still run a fair few Maranellos locally in both KA and 206. Their 206 chassis seems pretty nice.
Jumping back to the seat…you said standard T11? Not even T11t? Either way I’d try something softer, but especially in the case of the former. Seems like there’s a fundamental issue that’s causing everything to be just a little bit off for, so seat rigidity may be part of that issue.\
This probably belongs in the SH2 thread…but my brother and I had an interesting observation this past weekend as it relates to over-working the SH2 and it never being the same again. Very possible you hurt the tires trying things and from there you were fighting and tuning on hurt tires that weren’t going to do what you wanted and had you going in circles. From a development standpoint being locked into race rubber for the weekend probably hindered you in this scenario.
I’d be interested to know what the thing drives like next time out on new rubber.
…the long winded story of what we found this past weekend. Chris and I ran New Castle this weekend and unloaded Saturday for testing on the race tires from MCC the week before. Technically that set had 2 race days on them so they were 6 heat cycles total. The last lap of the MCC race Chris pushed super hard on the last lap trying to catch me, took risks that worked and he set the track record for 390 masters weight by almost .2 over the previous record. So the very last lap on track these things ran they set a track record. 6 days later we unload at New Castle and his kart was complete junk, mine was great. Over the course of Saturday we changed EVERYTHING on his kart (axles / caster / width / you name it) and every session the thing just got slower and slower. At the end of the day he as almost 2 seconds a lap slower than me and lost. The kart wouldn’t turn-in, wouldn’t jack on entry, would slide then grip then flat slide again…just a mess, didn’t do anything right and wasn’t responding to changes.
Sunday he went back to basically where we unloaded except one step softer on rear axle and when we bolted on fresh rubber for qualifying the kart was fine. It was fast in qualifying and fast in the race. So the only explanation that we’re left with is somehow in that last lap or last couple laps of the MCC race the week before he worked the tires soo hard that he hurt them and they never recovered. Chris stores his rubber in tire bags in a climate controlled setting to not leave them in harsh conditions…mine sat in the trailer all week!!! It was mind blowing to see but a data point we have yet to put our heads around. Those tires just somehow went to shit with only 6 heat cycles on them with no good reason as to why other than potentially over-working them and hurting them.
So this is extremely similar to what happened with me. I ran within a couple tenths of leaders’ times which is scorching for me. Not quite a class record but I was thrilled, haha. It was a PB by over a second. I was chasing a faster driver, so it was a combo of a good carrot, a good draft, and I was finally getting a good setup on my new-to-me FS4 (Chris with Prodigy has been a huge help). This personal best was heat cycle 15 or so on those tires. I parked the kart for a week and then entered the next club race and it just felt miserable. I could not get the kart to turn to save my life.
That event was a total bust, but then I chose to keep the tires on and do more testing to see if it was just a bad weekend for me or if the tires were shot. I ended up getting a little more pace back by really jumping the pressures up. Seems like, after they are cooked, they don’t build heat any more.
VERY interesting Andy, thanks for that write-up. I know I over-worked the tires a bit early in the weekend with understeer, but that’s not unusual in my past experience. I assumed they would come back if we fixed the kart’s handling, but nothing we did made a difference. This adds fuel to that theory I was tossing around that the tires just got melted and were toasted and never coming back. I would really like to see the results if Prodigy gets out and does a back-to-back with mine and Byron’s tires from the race to see if there’s anything there. We talked about that at the end of the night but blaming tires is one of the last excuses I would ever drag out. I’ll try and dig into this more.
Reviewing the trend of my pace over the weekend, I definitely was better when the track was warmer in the middle of the day, and when we got to the night racing, the kart got worse and worse. We also struggled after qualifying to generate tire temp and we were getting worked in the first 5 laps of every race. But then it felt like the tires were just completely overheated with 2 to go. So something wacky was up with how they were building and maintaining temperature.
Only one thing to do now broski, and you know it better than me…
The only thing to do once you get sucked into the “surely this is it, the magic silver bullet” is to scrap everything and go back to factory settings, and try again from scratch.
I appreciate your efforts in trying to make the thing work, but being forced to deviate so far from baseline seems like there is either someting fundamentally wrong with the frame or you got lost. I would suggest re-setting completely and going again.
Problem is you guys hardly have tracks that keep “racing conditions” during random, non race weekend testing, so it is an added layer when trying to find a decent setup…
Yes, as soon as I lowered the seat back and got close to the window again I should’ve just totally reset and gone with the setup I’ve been developing all year. Should’ve would’ve could’ve!
We got lost chasing a setup we were unfamiliar with because we lost track time with the new seat position. That’s totally my fault. Then we probably torched the tires to death trying to drive a setup that wasn’t suiting me. Series of unfortunate events.
13 actually isn’t that high for the SH2. I pretty regularly start my tires at ambient in the 12-13 range. If you were really stuck, I wonder if something like 15-16 would have worked.
But, I agree with the consensus above that the tires got cooked.
I think it probably wouldn’t have been as stuck at the high pressure, like @dodo noted on his tires. Would keep the tire from binding a bit. But we already were overheating them within 5-6 laps so I was worried about going too high.
Now that I mention that, that’s another strange aspect on the tires from the weekend. Typically on the 9F wheels I see zero drop-off over a run. 20+ laps and the tire stays in. But I could not keep them alive for more than 6 laps on this weekend. It felt like I was on aluminum wheels.
