SKUSA IAME 175 SSE Rule Changes

Apparently the changes required a reaction from Stars… :person_shrugging:

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Is it a reaction based on hype from one day at one race, tho? Seems like a decision based on optics, but Utah will tell us if there’s a real difference and it wasn’t just a track specific advantage.

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Personally, I wasn’t aware that they even made the changes to open up ignition timing and squish. Seems like that change wasn’t announced in the same manner as past updates to the SKUSA technical regulations? Either way, there was parity across platforms with the old regulations, so I’m with Stars on this one. There have been plenty of Pro races with SSE’s against KZ’s, and this is the first one where the result has overwhelmingly favored the SSE. Billy is an outstanding driver, and the Factory Kart is a fast chassis, but let’s not forget the caliber of field he was up against at Orlando.

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Can anyone weigh in on the change of the exhaust spacer requirement to the SSE having an effect at Orlando? Was Musgrave running with/without one?

Exhaust spacer was allowed to be eliminated early/mid 2022. It didn’t change much overall.

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Eliminating the exhaust spacer just raised the power band. The original intent of running the spacer was to keep RPM down and extend the life of the components. It had minimal effect on lap time.

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Anyone find documentation on the changes?

It sounds like there were other concessions made including port timing and squish, possibly head volume. Basically it went from stock 175 to “mild mod” 175.

Do you have references for these alterations/changes? Ignition and squish open, no exhaust spacer, and carb option is all that’s published that I can find.

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I haven’t been able to find the previous rules to compare if the porting limits have been changed but the SKUSA rulebook does spec open timing and squish.

Here’s some more explanation on the Stars post.

I tend to agree with others, usually KZ is very close amongst the top 3 to 5 (depending on who turns up). It’s very rare for someone to blow the field away.

Thinking through this a bit more, the port durations for the SSE must still fall within the tolerances the fiche, e.g. exhaust duration 195* +/- 2*. These constraints, along with open squish, are what permit modifications to the cylinder head. I think they went too far with these rule changes, and hope they pull back to restore parity.

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Unless the intention is to kill KZ and run an only IAME series.

It’s not like teams will stop turning up, they’ll just migrate over to the SSE after a few months of complaining.

The teams have already been on the 175, and it’s not a good look for SKUSA to stack the deck. There’s enough momentum with KZ that SKUSA would be stupid to disrupt it. Also consider that there is an alternative outlet for KZ with USPKS now hosting the category.

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Yeah I would think it wouldn’t be wise to really force everyone to invest in the 175 a second time. I would think those that had planned on running pro tour would just divert to uspks and that would become the premier KZ series. Just my thoughts however.

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Good call on the split @KartingIsLife

We were really derailing that thread. :joy:

If there is indeed a clear cut advantage to the new rules on bigger tracks, then yes they should walk it back.

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The direction ignition and squish were moved was not necessarily in the direction you’d normally move them to build an “open” engine. Factory had over a dozen engine failures at the SuperNationals last year including two that would’ve looked like a break on a pool table if the drivers behind them had been a little closer.

If you think the SSE 175 has an advantage and that there’s some MRC secret trick to the setup - the entire powertrain package is available either new or rebuilt. Call Willy Musgrave (951) 314-4595 to arrange payment and shipment.

The plot thickens…

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Not a bad move on their part, especially considering there were no 175 entires in round one.

With Stars and USPKS both putting out logical responses, I’ll be curious to see what SKUSA’s shifter numbers look like going forward. My bet is they make a change mid-weekend at Utah once they have more data :popcorn:

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I don’t think anyone’s implying a “secret trick”.

Just a rule change that made a difference and the overiding feedback from everyone except those that benefited from it is that it’s not good for the class. As a result series are dropping the SSE like a hot cake.

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Billy can win on any chassis and KZ or 175. But watching back the highlights from OKC, he yanks the KZs by a kart length or two in each hairpin.

Again, not taking away anything from Billy or MRC or Factory, but just what I saw.

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I enjoyed hearing Billy and his story on KC last night. Articulate guy with a clear passion for racing and all of its facets.

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