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Discussion Starter · #1 ·
Another good day.

Great day in many ways.

Started off pretty early, meeting MW on I-15 just north of SD. Rolled into California Speedway about 6:40am. Skies were pretty clear and the temps were crisp.

Steve W was doing the Evolution School being held in the same lot. Mikester was there with his Miata. MW had her Elise. Patricko had his Elise. Shinoo showed up later with his Chrome Orange car, so we had a total of 5 Elises there. And a lot of Elisetalkers also showed up for rides or to hang out.

Step one for me was to install our new custom swaybar. Well, that did not go well. It turned out I had to remove the second riveted in panel, except now I did not have a drill or dremel. Many snips with a small cutting tool finally removed the three large rivets.

Then, none of our ideas to enable us to turn the bushing bolts worked. So it was back to "insert allen wrench, turn 1/4. Remove. Insert. Rinse, repeat. It took about an hour to get them all in. I missed an entire run group.

So how did the bar work? Consider that the entire idea of the bar is to reduce or remove the inside rear wheel spin on corner exit. It is also hoped that the new bar does not introduce any problematic characteristics.

On the goal, it seemed to work very well. Inside rear wheel spin increases as the grip of the surface increases (think warm concrete) and this was not that grippy. But I could not perceive ANY inside rear wheel spin. And that was our achilles heel at our last event.

Did it do any bad things? Well, that depends. It changed the car. And it changed it in a way that worked against my style of driving, and for Robert's style of driving. Basically it increase corner entry understeer, specially in transitions. It did not feel like it was plowing a lot on the major corners, but corner entry felt less crisp. Less darty. It penalized me for diving in too late and forcing some oversteer to rotate the car. That technique was not working as well. It rewarded earlier braking and smoother transitions.

So... can we get away with a bar with a little less stiffness? Maybe. On the other hand, once we hit a concrete surface, this might be the ticket or possibly not even enough. The good news is that there is adjustment in this bar and I had it set to full soft.

I had a hard time comparing our times to other drivers that are a known standard to judge against. We were doing low to mid 52 second runs. Normally with passengers.

We also had a third driver, Mari Clements try the car. She is considering co-driving my car nationally. I think she liked it. And she did very well, getting down to 53 seconds on her second run. Mari has a car transporter and has offered to transport the Elise around the western US and also to Kansas in September as a co-driver.
 

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Discussion Starter · #2 ·
Spent lunch time, and then the run group following, removing the Quick Silver Exhaust and replacing it with the SQ Track. The track version sounded a little quieter and still nice.

We will get real sound data from Mikester who brought his meter and stuff.

I don't know how many runs we got in. I spent a lot of time under my car. I think some people got near 20 runs today.
 

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Discussion Starter · #4 ·
If I recall correctly, I think it is 140-160%, hollow bar with same OD but thicker wall.

Feels substantial compared to the stock bar.

The new bar has 3 holes in it. A production bar may have more, but will require different endlinks.

I am thinking of replacing the rivets with other fasteners.
 

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Discussion Starter · #5 ·
Forgot to post some conclusions.

I *think* we will stay with this bar for a while. We had considered going softer or stiffer it was obvious to do so. In other words, if we still had wheel spin issues, or the car was impossible to turn.

Some of the new handling characteristics can probably be tuned out with alignment and eventually with different shocks.

The main conclusion is this:

The weak point on the Elise in autocross is inside rear wheel spin. Feathering the throttle when coming out of the corners is slower than mashing it. :)

So you put on a front bar as stiff as it has to be, in order to remove the inside rear wheel spin.

And then you tune around that bar. You can follow some steps to reduce understeer or induce oversteer. Your main tuning techniques are alignment, shock settings, tire pressures.

The main bar related questions still are:

1. Would we be better off with a slightly less stiff bar?

2. Is the bar stiff enough for grippy tires on concrete? Or will we need a separate bar for different surtaces?
 

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Discussion Starter · #6 ·
Also, I believe it is Robert's plan to make this bar available for sale. So if you are interested, that might be an option.

The downside is that it is not that easy for someone to swap a bar, though certainly doable. Robert may have to supply a special allen wrench.
 

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I'll be very interested in your results on different surfaces. It sounds like we'll have to learn to drive the car all over again if we switch. I'm interested in one of Robert's bars for sure, if he chooses to sell. Of course my issues are a lot different from all of yours-I probably couldn't tell you what the problem is, if I have one :rolleyes:
 

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>>>If I recall correctly, I think it is 140-160%, hollow bar with same OD but thicker wall.<<<

Sounds like you may be using the stock rubber bushings. You can affect the net rate about 20-30% by going softer or stiffer with the mount bushings. They can be changed from the wheel well. But you'd have to face those allen bolts again. The shortie hex and Sears ratchet I used really helped out when I changed my bushings. Big time saver.

Stan
 

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When you say 140%-160% do you mean its 2.4x ~ 2.6x the stock bar rate or are you saying its 140%-160% the stock bar rate meaning 1.4x~1.6x.
One thing to keep in mind is that all the top S2000 drivers get wheel spin but its a worse problem in that car, and they still run times very close to SS. When it happens in an S2000 you simply can not accelerate at all, even with throttle feathering, because the wheel is in the air. I routinely had it happen on low grip sealed pavement with victoracers, running a front bar that was ~3x the stock bar rate. I feel your pain:)
Great update, thanks for the info.
 

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Discussion Starter · #10 ·
z06fun said:
When you say 140%-160% do you mean its 2.4x ~ 2.6x the stock bar rate or are you saying its 140%-160% the stock bar rate meaning 1.4x~1.6x.
1.4-1.6 times.

That may have been arough seat-of-the-pants guess from the fabricator. I intend on doing some calculations.
 
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