Brief update on FJ spec motor proposal

Danny Kao · Joined: 17 Nov 2008 Posts: 192

Hello, Happy Holidays and early Happy New Year to all.

First of all, the said proposal/presentation is circulating among the KAC/SEB now. We have heard a few feedbacks, generally positive. Since the rule is not finalized, I will state what is happening right now and what I know.

1. The slide restrictor for JB, in some of our opinion, is a good option. We have dyno tested thru an independent Briggs motor builder in Ohio recommended by Briggs Racing. I also did a non-scientific restrictor testing with a FJ parent in Richmond and the motor runs well with the restrictor; and we can see a measurable time increase on the test runs as the restrictor size increases. We are also arranging another dyno test between WF and another top JB motor and we will provide all dynos and testing data when the rules are out for member comment.

2. We met with the Director of Briggs Racing last week and had a great meeting with him. Based on the meeting, we will be receiving the slide restrictor, check tool and locking cap for every region that offers JB program. An additional 50 restrictors sets and tools will also be made by Briggs free of charge to any JB racer running a World Formula. Contingency and motor purchase rebates are also in the works, most likely in a form of free entries to SCCA National events. Again all these were talked about in our preliminary meeting; but I feel very positive that Briggs are doing their best to accommodate us.

3. The junior spec motor rule is currently proposed to take effect in 2013 with a sunset rule for the rest of the motors until the end of 2015. The rule is not approved by KAC or SEB yet so it's not official. The slide restrictor rule for JB will most like take effect by March of 2012 pending our final dyno testing to determine if there is going to be any weight penalty for the WF in JB configuration. We feel we selected the right restrictor for the JB WF but we are using our final dyno test as confirmation.

4. I had quite a bit of conversations with Briggs and FJ parents. Based on what I have heard in our conversations this is my "opinion": (and my only)

a. Multiple sources told me blueprinting really doesn't offer any power advantage. Blueprinting to a new WF is not necessary. (This is based on what I heard from multiple sources; if you heard differently please let me know. Director of Briggs Racing told us himself that every motor is hand build and inspected to the best spec possible and they are not mass stamped.)

b. Overbore up to 0.030" and use 0.030" over piston does not offer measure difference in power.

c. It is measurably cheaper to overbore (if necessary) the cylinder during the rebuild instead of new cylinders. (Savings of ~$200)

Briggs racing is kind enough to provide us the baseline engine rule set written specifically for our requirements. Blueprinting and engine rebuilding will be addressed in the rule set. I think many people echo with me that FJ (and for that matter, autocrossing) is not about who has the biggest pocket but rather who is the best driver that wins. We will certainly be reminded of that at all times.

5. The junior spec motor rule only applies to SCCA National events. The current motor rules still apply to all regional races.

I hope this gives you an idea on where we are at with this rule proposal. KAC does not meet again until 3rd week of February so the earliest you will see this is probably in March's Fastrack.

And also I am not the spokesperson for KAC nor the Chairman. Most people feel Chairman Kao sounds too much like a ruthless dictator; so instead I am the designated punishing bag for your enjoyment. Wink

Steve Ekstrand · Joined: 15 Dec 2008 Posts: 6

I really appreciate the update. The direct involvement of Briggs is particularly exciting.

Would the motor ruleset differ significantly from current IKF/WKA rulesets. I know nothing about those other rulesets, I only ask because I have been purchasing and selling our kart stuff through the sprinter channels not auto crossers. If it differs it could be a negative but one outweighed if you truly could purchase an off the shelf Briggs motor and win with driver skill.

Thanks again for the hard work and for sharing the progress.

Joe Ricard · Posted: Wed Dec 28, 2011 4:32 am Post subject:

Thanks Danny aka (punishing bag Kao) Very Happy

Dixie tour is in March
We have a WF
We are ready for the tour with exeption of the longer throttle slide Would love to get a local event in before the tour in the new rule set.

Keep us updated and great work!!!!!!!!!
_________________
Arrow AX-8/ Rotax Sr.

Danny Kao · Joined: 17 Nov 2008 Posts: 192

This is just mine and not the committee's opinion, but the proposed engine rule will be as stock as possible with the overbore allowance for rebuilding purpose only and not to gain a competitive advantage. We will consult Briggs more on blueprinting; I am guessing blueprinting should be allowed since there is no measurable advantage based on what I have heard, especially comparing with the new motor. For now gearing is still under debate: we definitely want to make sure JB doesn't go so fast to cause harm to the driver, but we don't want it to go so slow that everybody gets the same time. An idea of three gear sets with three different top speeds is flowing around right now and we are gathering some test data; but it's on the table and I am sure your comment and help is greatly needed.

Joe, I will be at Dixie also. I am hoping the JB "kit" will be available by then as we are shooting for the package to be available at least by mid February. If you have a WF already and like to run some tests with the restrictor, please send me your mailing address offline. I had two made that has the exact same spec of the proposed restrictor and I can send you one. I am interested to hear your impression on the ease of install and the performance of the motor with it. Thanks!

Brian Garfield · Posted: Wed Dec 28, 2011 2:44 pm Post subject:

One thing you'll want to talk to Briggs about is how there is a lot more necessary to mount up a BWF and all the trimmings. In my research, if you don't have a 4 Stroke chassis, there's some cutting of seat struts needed or the jackshaft setup for using a BWF on the 2 stroke chassis.

I ran the numbers and with Julian's Arrow chassis (already a 4 stroke chassis) we're looking at motor ($900-$1000) plus $300-$400 more of stuff we don't already have. A discount would go a LONG way to getting people into these things...

Brian

Andrew Peppler · Joined: 08 Aug 2010 Posts: 91

Also, we may want to spec the rev limiter. I'm not familiar with the engine, but it looks like the rev limiter may be removed and/or changed.

It would also be worthwhile to FJ parents to do a write up on how to mount a new engine and to hook everything up. A video would be great, or even a word document with pictures would be very worthwhile. Something that covers from removing the engine from the shipping box all the way to get it mounted with clutch and throttle/gas hooked up with all the additional parts like what type of engine mount. I think that would be great for parents who are not familiar karts... or even for those that are! I'd help with that, but we'll still be running the KT this year and maybe budget for a different chassis and WF for 2013.

Danny Kao · Joined: 17 Nov 2008 Posts: 192

Tom and I did ask Briggs specifically on the engine fitting on chassis. On the chassis that has fitting issues we were told either use an offset engine mounting plate, or bend the right side seat strut slightly will give enough clearance. I haven't seen it first hand however.

For the new motor purchase rebate, I did the best I could other than getting on my knees begging; but Brian knows I am a lousy negotiator so it really doesn't say much. I do know regardless on the rebate, Briggs will not issue checks individually to the motor purchaser and it has to come from an organization like resellers or SCCA.

We were also assured that any new motor purchase after our meeting date (December 21, 2011) will qualify for whatever the rebate is. So if anyone is buying a new motor, please save your receipts and UPC code from the box.

Danny Kao · Joined: 17 Nov 2008 Posts: 192

Dale Seeley · Posted: Wed Dec 28, 2011 4:23 pm Post subject:

Since people are smart enough to buy their WF engines from a local dealer/kartshop instead of trying to save $5 buying off the internet, installation should be no problem at the kartshop. They mount engines and batteries and 4 stroke gearhubs all the time.

They will probably also help you with getting it running right at the events if you ask nicely.

The "extra" money spent at a kartshop that is local to you is invaluable when you need help.

Joe Ricard · Posted: Wed Dec 28, 2011 4:55 pm Post subject:

I managed to install the WF on my son's Birel Cadet. Even had two seat struts on both sides.

No it wasn't easy but once I got the Burris two piece adjustable mount it was much easier.
_________________
Arrow AX-8/ Rotax Sr.

Richard Jung · Joined: 14 Aug 2009 Posts: 25

Hey Danny,

Thanks to you and the KAC for all the research/work put into this issue. I appreciate the sunset rule until 2015, as some of us have time and $ invested with multiple motors this year.

Rick

Richard Jung · Joined: 14 Aug 2009 Posts: 25

Double post

Matt Miskoe · Joined: 27 Dec 2011 Posts: 14

Sorry to be late to the party here, but would this proposal be to run the Briggs motor ONLY or would the two strokes still be an option in FJ?

My son has a CRG chassis that is really not set up for any motor that has it's drive on the left side. There is a frame member that limits the size of sprocket you can use on the axle and the clutch is nearly rubbing on the seat. We've been running a Raptor, but it is not an optimum set up. Can I refabricate it? Yes. Do I want to? No. It's a brand new chassi, I'd rather not go hacking it up.

I would think this is not a unique situation.

Scott Boito · Posted: Mon Jan 02, 2012 7:56 am Post subject:

Matt,

The idea is to move to Briggs WF-only Junior classes over a few years, with the 2-strokes and other currently-approved motors being phased out over that time. So for this season and the following 2-3, folks would be able to run either/or. After this sunset period, only the Briggs WF would be allowed.

Does that answer all of your questions?

Scott (also a KAC member speaking in an unofficial capacity).
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KM #68 - Haase/Honda kart
BetterOffRacing
Member of the SCCA KAC

Matt Miskoe · Joined: 27 Dec 2011 Posts: 14

Scott:

This does answer my question for what is being proposed, can you give me some history on why it's needed?

On first read I think I don't like it for two reasons. There are plenty of chassis out there that don't accept a LH drive motor very well (the one I just got). Second reason is that the local wheel to wheel racing groups don't accept the WF motor, so if Solo requires it, I'll either need a seperate motor to go racing, or there won't be any options for other clubs to race with. More optoins often means more racing.

Again, I'm pretty late to the party here and last year was the first season my kids have done any Solo so I am a a newcomer by all accounts. So I really don't have all the history and therefore am not fully qualified to judge.

Thanks
Matt