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Final Race Weekend of Season

 
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1099
Location: Maysville, Colorado

PostPosted: Tue Oct 26, 2021 7:39 am    Post subject: Final Race Weekend of Season Reply with quote

Had our final go round at La Junta CO track, a short 1.2 mile old WWII airport training base. Our vintage group emphasizes track time so the track was very seldom quiet for more than 2 or 3 minutes. With four race groups we got in 1 qualifying session and 4 15 minute races on Saturday, Practice and 3 races Sunday. It came out to 1 hr 45 minutes to track time or a possible over 100 laps.

Most of the cars are 40 to 50 year old race cars, of course the motors and suspensions have been upgraded with time and a 1275 Sprite can have 135HP pretty easily so a power to weight ratio of about 11lb/hp, I'm at about 16 to 17 so at a tremendous disadvantage on acceleration. So I'm about the slowest in the group besides have a small fraction of the experience of mot of the folks.

I figured I got in about 75 laps on the 7 turn course two of which are a constant challenge. On Sunday morning I saw that the volt meter had dropped from 14 to 12 so I checked it out. It turned out that the bolt holding the lower alternator bracket to the block was gone. Putting it back together to have it not work I remembered the spacer between the block and the bracket. I had replaced the stock rubber one with a steel spacer so it was gone. I found in my bolt box a 12mm lock nut so put it in as a spacer and it worked ok. I lost the practice session and one race due to that. Managed to get my fastest time of the weekend in the last race of the year, a 25 minute one that I had been worried about before hand but was having such a good time I hated to have to stop.

The one necessary correction I found is that I have a great tendency to wheel lock up during trail braking. This was apparently a common problem with the Spec944 folks and they compensated with different brake pads front and rear. I have the same system so the current plan is to put a adjustable pressure reducer to the rear brakes. Almost everyone else has a dual cylinder balance bar setup, I still have the brake booster and stock MC.

A new 931 non turbo based motor of about 11.5 CR is in the works and I have a couple of small weight reduction projects planned for the winter as well as modifying the body front to make the entire valance removable for transport as with my current setup I have a 8 degree approach angle and have to have about 15foot ramps(really ugly) to get on the trailer so I change the front wheels to some that have old trailer tires on them to jack the front end up.
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Mike
Poco a Poco, #033 '78 Vintage racer, SCCA Dp-81
'77 924
cricketdesigns.com
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924RACR  



Joined: 29 Jul 2001
Posts: 8503
Location: Royal Oak, MI, USA

PostPosted: Tue Oct 26, 2021 8:57 pm    Post subject: Reply with quote

Strange with the braking; we have no such problems on our car, running the same compound front and rear.
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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Cedric  



Joined: 27 Aug 2004
Posts: 2236
Location: Sweden

PostPosted: Tue Oct 26, 2021 9:05 pm    Post subject: Reply with quote

924RACR wrote:
Strange with the braking; we have no such problems on our car, running the same compound front and rear.


Me neither, but weight bias might differ to a stripped na car.

Have you done a good corner weight adjustment?
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1099
Location: Maysville, Colorado

PostPosted: Tue Oct 26, 2021 10:12 pm    Post subject: Reply with quote

I do have the 944MC which is 19.8/23.4(that"s close) instead of the 19.8/19.8 from the 924. That might have something to do with it.

My last corner balance with the sway bars hooked up was quite close, adjusted 1 spring about 1/4 of a turn. Since then I have installed the Audi 5 speed which is supposedly 30 lbs heavier than the 4 speed. The front sway bar is mounted like the late aluminum A arm ones. pin thru the A arm, so it is quite difficult to get unloaded unless it is just disconnected from the car. Rear is a Weltmeister so easily detachable and adjustable. The closest corner balance scale I know of is about 5 hours across the mountains so not much fun to get to with winter on the way.

These suggestions do give me food for thought, I need to take apart the suspension and to a total reset and inspection over the winter so I'll try to come with a way to get the balance better.
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Mike
Poco a Poco, #033 '78 Vintage racer, SCCA Dp-81
'77 924
cricketdesigns.com
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