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850 Sport Coupe series 2 track car.

Discussion in 'Rear-Engine Fiats' started by ramona300, Oct 1, 2015.

  1. ramona300

    ramona300 Daily Driver

    After lots of research into BMW E30's and Datsun 1600's which have similar rear suspensions the raised pivot points seem to be the way to go. Looking at the car today the front pivot point would be very easy to do. The rear will have to wait till the gearbox/engine is out next but does not look that hard. About 20mm should be close to the mark.
     
    kmead likes this.
  2. kmead

    kmead True Classic

    Location:
    Grand Rapids, MI
    Yes that is the way it is normally dealt with when needing to decamber a semi trailing arm suspension, they did it this way on the original M3 which started as a standard E30 chassis as its basis. A negative is you tend to lose rear suspension travel.

    It may help you with your axle angularity to a limited degree. It would be nice to raise the transaxle and engine in the chassis to go along with this to keep the axle angles closer to neutral as the suspension goes through its range. One thing leads to another.

    Please post up the work when you have the opportunity to get around to it. Many thanks.
     
  3. ramona300

    ramona300 Daily Driver

    The photo is my car at the start of the local hillclimb. The rear coils are shortened stock items. There is a lot of squat in the rear on take off. I have decided to replace the rear coils with heavier springs and also raise the ride height at the rear slightly. I would like to buy off the shelf items but the prices seem a bit over the top and there will some delay getting them posted out from Europe. The stock items have a free height of 236mm, I'm thinking about 200mm would suit. I can get new springs made in Sydney. Raising the car slightly will get rid of the excess negative camber I have at the moment which is too much for the Formula Ford crossply tyres. Anyone have any suggestions for coil specifications?
    [​IMG]
     
  4. NM850

    NM850 Daily Driver

    Location:
    Albuquerque NM
    After see the price of bespoke springs I decided to use springs from Landrum on my Alfa race car.
    For the price of one pair of bespoke springs I now have multiple pairs with various rates for different tracks.
    Available in many sizes and rate increments for about $80 US per pair. You mave have to change the perch slightly but I'm sure you could find something that would work.
    www.Landrumspring.com
     
  5. ramona300

    ramona300 Daily Driver

    Ended up ordering a set of 205mm coils from Scuderia Topolino in Germany. Tried the local company but there would have been several weeks wait and more expensive than from Germany. These coils seemed to be a popular choice as well.
    [​IMG]
     
    kmead likes this.
  6. kmead

    kmead True Classic

    Location:
    Grand Rapids, MI
    Let us know how they work out.

    Mine have naturally lowered a bit over time :) so getting some proper lowering springs would likely make things work better than they are now on my road car.

    Looking good, sorry for some of your teething issues at the recent hill climb with mixture and so on.

    Karl
     
    Last edited: Mar 4, 2017
  7. ramona300

    ramona300 Daily Driver

    Installed the new coils today. Less than two weeks from Germany. Seems high at the moment but once she gets mobile the height will come down. Slicks on the trailer holding it up somewhat.
     
    kmead likes this.
  8. ramona300

    ramona300 Daily Driver

    Early this month I trailer-ed the car down to one of our local circuits for the Fiat national weekend. I had entered the Super sprint and the following day a Motokana.Well I did not have a particularly good Fiat Nationals. Had a practice day at Marulan the Wednesday before and the car was running fairly well. Speed at that circuit is not as high as at Wakefield but I was fairly certain of my tune.
    Friday morning at the Supersprint it was a particularly cool morning and I thought I might have trouble starting with E85. Pushed the car off the trailer and apart from a low battery the car started easily. I sat there for several minutes with the engine running at about 2500rpm waiting for the engine to warm up when it suddenly stopped. I was watching the O2 gauge at the time and it went lean just before it stopped. Car started again easily but would run only a second or two before stopping the same way. Fortunately one of the other competitors came along and helped me isolate the problem to the rising rate fuel regulator. As I started the car he noticed the fuel pressure gauge would pulse then go very high, this would have held the injectors closed hence the lean indication as the engine stopped. He checked there was no blockage in the return line. Normally I run a base pressure of 43 pounds. We tried 35 pounds and the engine started fine and run for longer but the gauge went high again. I presumed the E85 had damaged the cheap Chinese fuel regulator and visited 6 places in Goulburn looking for a replacement but no joy.
    When I got home I pulled the reg down expecting some damage but it seems OK, just some residue. Ordered a new Turbosmart rising rate fuel regulator that is E85 compatible and now have that installed and the car starts and runs fine but even with the same base pressure my AFR's are out! Lots more tuning ahead. The return line to the swirl tank is clear so there is no other reason why the high pressure problem would suddenly appear.
    Always other interesting cars at Fiat events. The photo is of a turbo charged 903 in a "Rail" motokana special. The owner builder has two injectors, one each side into the inlet tracks. I presume he missed the water jackets when he machined out the injector bosses. Running really low compression ratio of about 6:1 and 12 pounds of boost on 98 fuel. Ran well.

    [​IMG]
     
  9. ramona300

    ramona300 Daily Driver

    Turbosmart fuel regulator now installed and runs well. Strangely with the same base pressure as the Chinese item the AFR's are all out and the whole lot needs retuning. Car was a bit noisy so I installed a new larger straight through muffler and now have the outlet pointing straight down. I was inspired by one of the rails at the Fiat Nationals! Busy at the moment welding in the front half of the rollcage. I only had a halfcage but it was suggested I go the whole hog. It's now a major evolution getting into the drivers seat!
    [​IMG]
     
  10. ramona300

    ramona300 Daily Driver

    This maybe a little boring video for some. I made this mainly for Megasquirt/Tunerstudio fans to show the engine being tuned with the VE analzse programme. Engine is mainly idling in the video. Car has the wheels off the ground and the VE table is being tuned running in top gear. Next up I will drive the car around and let it self tune under various loads.
     
    kmead and NM850 like this.
  11. ramona300

    ramona300 Daily Driver

    Just had the kingpins refurbished at great expense. While they were out I changed the coil springs from 500+ lbs to 250 lbs. Also shifted the lower coil supports up a bit to provide more clearance with the upper wishbones, they were fouling a bit.
     

    Attached Files:

  12. kmead

    kmead True Classic

    Location:
    Grand Rapids, MI
    Kingpins, a job I need to do or get done. I bought an extra set of uprights so I can change one for them other.
     

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