zlalomz

http://www.scca.com/Event/Event.asp

tube80z

I was hoping to see the Zs beat the bimmer. I guess we'll wait for the other course and wish our boys well.

Cary

tholt29

Here are the shortened FP results:

1 Chris *** 1997 BMW M3 108.121
2 Scott Fraser 1995 BMW M3 108.777
3 John Thomas 1971 Nissan 240Z 109.399
4 Michael Tews 72 Datsun 240Z 110.148
5 Tom Holt 1974 Datsun 280Z 110.88
6 Jon Jackson 1973 Porsche 914- 111.696
7 Richard Holden 1976 Datsun 112.332
8 Jon Etkins 1974 Datsun 280Z 113.553
9 Robert Puertas 2005 Lotus Elise 114.205
10 Robert Lang 1973 Triumph TRG 114.324
11 Asher Wunderl 1985 Mazda RX7 114.411
12 Michael Hoyt 1992 Plymouth Laser 114.528
13 Randy Chase 2005 Lotus Elise 115.418
14 Kent Hoyt 1992 Plymouth Laser 117.978
15 Jason Hopkins 1985 Mazda RX7 118.533
16 Rick Martinez 1972 Datsun 280Z 120.383
17 Lucas Anderson 1972 Datsun 240Z 122.355
18 Charles Haynes 1976 Datsun 280Z 126.095

The good news for the class is we grew from 10 entries last year to 18 (plus 3 in Ladies class). That officially gets us over the minimum participation limit of 17 total, so we are no longer on "probation". The good news for the Datsuns is Chris *** is selling his BMW. He thinks he has a buyer in Colorado, hopefully the new owner will not be as talented, but that car is clearly the best in the class. It was built by professional car builder Tri Point Engineering of the Speed Channel Touring car series and the owner of that team is former FP champion so he knows autocross cars and setup... Chris is also really good at car setup and driving. That said, John Thomas showed on day 2 that he could beat Chris.
This event got off to a horrible start due to weather and because of various delays the FP heat didn't take their first runs until about 6:35 Tuesday Night. By 7:45 it was too dark to continue and we were told to be back in grid at 7:00AM to take out third runs. John had been having fuel delivery problems and cone troubles on his first runs. He got the fuel problem fixed and managed a good clean time on cold tires Wednesday morning. I got faster Wednesday morning but hit a stupid cone! Wednesday afternoon John set fast time on the South course but it was too little too late to catch Chris. I just didn't go fast enough to improve my position. Mike Tews did a great job driving the Andersons Z. It broke the diff on his 3rd run, but he got lucky and got red flagged so he got a rerun. His car was dead so I let him drive my car, but the set up was so different that after about 2 turns he decided he didn't want to break another car and just took it easy.
The weather was hit or miss all week until Friday, but it's alwas fun to get out there and slug it out with the bigger crowd. Next year the event moves to Heartland Park raceway on brand new asphalt, so we will have a better event site. If you have never been, go... you won't regret it!

Tom #5

tube80z

Thanks for the update Tom. What a bummer having to start the next day out cold, hopefully everyone had to run in similar conditions. I know my car's performance is effected a lot by pavement temperature. Eventually I'll figure out how to make it work better in the cold.

I've always been curious how much adjustment national level people make to their cars in a situation like this. Do you change settings for the cold or wet or between runs?

Cary

tholt29

Actually the morning run stood to benefit me the most... We met at sun up and were told that anyone who took their third run in the dark the night before could drop that run and take a new run in the morning. Everyone opted to run third runs in the morning, including my co driver, so all second drivers would have at least some heat in their tires. We were also told that we would start immediately and that we would pause for the national anthem and then resume. Since they run in numerical order, my co driver was the last first driver and they held him at the line while the anthem and flag procession went on for about 5 or 10 minutes, meanwhile everybody elses tires are cooling back down. Once we resumed, Jon came back in witrh nice warm tires which we covered to keep as warm as possible. I took my final run about 5 minutes after the car came back in while everyone else had to wait about 15+ minutes. Then I went out and hit a damned cone!

I know some of the guys will disconnect sway bars or adjust shocks when running in the rain. I keep the setup the same and just put on the rain tires when needed. I'm too lazy to be that competitive!

Tom

zlalomz

Hi Tom, congrats on your trophy again this year even with a cone. I was wondering
if "wunderkind" John Thomas did anything much different on his car than yours? Did he have any kind of cage? I remember you said he was asking you about suspension set up while he was building his car last year.

tholt29

John's car isn't radically different from mine. It's basically an FP car that can do duty on a road course. The cage is pretty much overkilled for an autocross car and he has semi big fuel cell (for an autocross car). The brakes are overkilled etc... The only thing he's done that I haven't (yet) is tubular conrol arms. He built some pretty simple ones that are not adjustable on the car. He also spent the big bucks on a Rebello motor. Otherwise it's about the same as mine, except blue!
I'll try and post a few pictures...

tholt29

Welll... that didn't work... Let me try again...

zlalomz

I wonder if he raised the rear inner arm pivots to raise the rear roll center. I was trying to figure out something like that in my head so its great seeing it layed out on a workbench. I never thought of just using rectangular tubing to put the heim joints in double shear. Great pictures, thank you.

Did you notice if he was running a lower ride height than your car Tom? The only exterior picture I have seen of John's car is the small one on the SCCA website.


Well this is exciting about the number of entries in FP this year at the nationals. I thought this was the swan song for FP and all the Z's would be moving to AP again.

tube80z

This is what was more or less discussed on hybridz a while back. A couple of suggestions if you go down this path.

For the tubing orient so that the long side if the rectangle resists the force and mount the heims with bolts up and down. This will give you less friction and be stiffer. X brace the bottom and the back to make the box stiffer. Move the exhaust somewhere else. If you want to play with rear RCs you can use spacers to change the height of this tubing from the car body on the front and multiple holes on the rear.

For the amrs I'd opt for a simpler formula car arrangement with an included toe link. And you'll probably need to remove the inner bar as it will foul the u-joint. It's cool to see someone building this kind of stuff.

Cary

zlalomz

Sounds good Cary. Could you measure some formula car arms at the next event to see if some trick aero shaped carbon fiber arms could be adapted for Z use. Now I have to look up "toe link" and find that Hybrid Z thread.
So are you saying on heim orientation, the ideal way with the bolt vertical would be how the front arm and T/C arm heim joint should be oriented too? edit: I found you talking about heim orientation in the front control arms but am still looking for the rear control arm question on Hybrid.

tube80z

I'm not using formula car parts for anything other than inspiration. For the heims you'll find it takes a lot less effort to move them when they are mounted with the bolts up and down. Since we don't have a lot of suspension movement you don't need to worry about binding. Try putting one in a vice and moving across versus rotating and you'll see what I mean.

I would change the orientation of the front control arms and TC rods to work the same way. It's a number of small details like this that end up making a difference.

Another trick is to spin the heims to clearance the teflon liner. You put them in a drill prress and turn them until they start to tighten. Then immediately dunk them in ice water. This shrinks the liner a minute amount.

Here are a couple of pics of the rear suspension.

Rear view of suspension

zlalomz

Hey Cary. you wouldn't have a spare set of those arms laying around would you? I found all of the Hybrid threads last night and I assume that is a toe link on the back of your arms and geez, will you please finish your monster so we can all be in awe. (oops... I can't say anything about construction speed) Out of curiosity, would using long arms like yours in the rear with stock length up front cause weird things to happen?

tube80z

It might make the back stick better. The long arms help to change the amount everything moves. You get less movement of the contact patch and things like IC, RCs, and all those other peskies calm down.

If you're going to keep the stock front arms I'd make it more like John's with a little shorter arm. The toe link is in the back and really serves no other purpose than to let you adjust toe easily. Obvisouly this hasn't been used in combat but the design has on other things and seems to work. So we'll see.

I have a jig so for the rear arms so they aren't that hard to build. They won't easily fit a stock car as I tried to use them on my current car. I raised the diff on the tube car to make room for them. And the tube80 has to get finished this year. I'm getting rid of the parts car so I won't have anything to run unless I finish it. That is my main motivation.

Wish me luck,

Cary

zlalomz

Good Luck!!!!!!!!!

I assume the arms are made from chromoly?

tube80z

This is on the cheap, plain ol' mild steel -- just thicker. If it all works maybe the next one will have some better materials. The chassis probably costs around $500 in metal total. It's the $15K in parts that are hung on it that are expensive. This project is really about building a fast car with as much ordinary content as I can and only spending money where needed (or that's the story I'm sticking to).

Cary

zlalomz

Hey Tom, if you are still checking this thread, were the Lotus Elises just "stock cars" with slicks... well as stock as a Lotus gets or were they truly prepared. Just wondering how much of a threat down the road they might be.

tube80z

I can't say that I know the answer to this one for sure but on another list it was mentioned that they weren't too prepared. The good news is that in prepared most of the advantage cars like this would have can be mitigated. We can add cages to stiffen the structure as well as change te suspension geometry. The only thing we can't do a lot about is weight and balance, but performance adjustments are usually are routinely given to cars.

Cary

tholt29

The Elise in FP was the exact same one that Mike Johnson drove to a 4th place finish in SS. It had some Penske or other high end shocks and they were running a set of hoosier cantilvered slicks. The drivers seemed to have a bit of trouble with cones mainly due to the drivers lack of experience on slicks. In spite of that, they were turning mid pack times. The calculated weight for the Elise would be something around 1350, but the class minimum is 1900 which is just under the curb weight of the Elise. The Prepared committee voted voted to keep that 1900 min rather than open the door to a lightweight car coming in and dominating the class.

Tom