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May 6, 2011 11:41 a.m. bearmtnmartin None

So I am new here although lurking for years. I went to ask this question on another site I frequent but it seems to be down this morning, and there does seem to be a lot of track knowlege over here. Also BMW's and Maitas, but I don't discriminate, so neither should you when you find that this is a banger class oval question.

Last year I ran a FWD and it was an evil handling pig. It took all year to sort it out and that was no fun. This year I have a 240sx twin cam and it is fast right out of the box. It also handled beautifully. I can pitch it into the turns and it drifts nicely around until I want to straighten out. If it pushes I can add some power and the tail comes around and the push stops. I am not the best yet at reading car behavior, but I would say it pushes a bit mid turn if anything. But very controllable with the back end.

So for my first race day with this car, I ran right at the front, which was a new place for me, and I want to stay there. But looking at my times tells me that I have to find about 4/10 of a second per lap to really compete. So I am looking for some small mods which will help me tweak the handling without wrecking it like I did on my last car. I don't have the time or test days to spend countless hours trying things that may or may not work. I figure if I can find 2/10ths in my driving, and 2/10ths in the suspension, it is going to be a really good year.

For the record, it is a stock class, and all I can do is work the grey areas. The car is completely lightened to a ridiculous degree, and I have dropped the rear swaybar to reduce the push, which it did. I am running the max allowed camber at the front at 1.5 deg neg right and pos left. Toe is 1/8 inch. We are not allowed to corner weight but I have craftily shimmed the struts to get more weight on the back left.

I have to say that I am a road racer at heart, and I did the circle track thing as a bit of a joke. But it has turned into the most fun I have ever had, and I strongly reccomend it to anyone who wants to race on the cheap. You get huge track time, and learn a crazy amount of car control and suspension setup without breaking the bank.
May 6, 2011 12:01 p.m. Jerry From LA HalfDork

How much do you weigh personally? Seriously, losing ten pounds is like adding one horsepower. So if you have more to spare, there could be a tenth or so in that.....
May 6, 2011 1:21 p.m. ransom Reader

Dropped the rear sway bar to reduce push? As in removed it? I'd have expected the opposite result...

Continuing the "I don't know a darned thing about ovals" theme, the wedge (do I have my oval terms right?) you've applied should, in theory, increase understeer. By putting more weight on the LR, you're also adding it to the RF, and taking it off the LF and RR. In a left hand corner, this is effectively a bit like running a stiffer front sway bar. Which is to say that more of the weight transfer from cornering is being supported by the front outside tire than the rear outside.

When you transfer weight laterally across the car unevenly between the ends, the "stiffer" end loses some efficiency and the "softer" end gains some.

I'm pretty sure there's a lot oval setup stuff that's counterintuitive to me but works as a complete package, so take my observations with a grain of salt. I'm pretty sure they're correct, but they may not be directly applicable in your case.

Sounds like the car's pretty well-behaved overall, but I suppose it'd be quicker if you A) didn't need to get it sliding with the throttle to get it turned, and B) you could get on the throttle earlier without getting it sliding...

Not sure whether these are attainable goals within the stock suspension and rules...
May 6, 2011 1:54 p.m. alfadriver SuperDork

In reply to ransom:

Yes, but since it doesn't.... (going on the odd sense, not really disagreeing with you)..

If reducing the rear roll helps understeer, perhaps you are loosing camber control on the front? Do you have any pictures?

If that is the case, which is actually a common problem on Alfas and VW's- we tend to increase front roll resistance- aka- stiffer front sway bar/ stiffer front springs.

Can you get a slightly stiffer front bar?

Oh, and did removing the rear bar make the car faster in time, or just feel like it's pushing less? The hard part is if the car is slower, but you are more comfortable/confident with it.... if that's the case, I'm not sure which way to go.

Anyway, if removing the rear sway bar makes it understeer less, I would suggest going to a stiffer front bar.

That's kind of the way to go in opposite world.

Editorial- the circle track guys I know- ones we kart with every once in a while- are really good road course drivers. Very, very good. So even if you have to turn left, I bet you'll do it faster than when you were not racing.
May 6, 2011 2:08 p.m. foxtrapper SuperDork

bearmtnmartin wrote:

I am not the best yet at reading car behavior...So I am looking for some small mods which will help me tweak the handling without wrecking it like I did on my last car.

Then work on you.

Seriously.

The single best modification that can be made is the driver. A good driver in a clapped out Yogo will lap a clod driving a Ferarri.

You say you're not the best at reading the cars behavior, become fantastic at it. Then you will be able to tell when you've some more room to push the car a bit faster, or brake a bit later. All of which produces faster laps.
May 6, 2011 2:28 p.m. Tom Heath Web Manager

As others suggested, driver mods are always effective.

My next step would probably be alignment changes; they're free (if you do them yourself) and can be incredibly helpful if all your turns go in the same direction.
May 6, 2011 3:24 p.m. ransom Reader

alfadriver wrote:

In reply to ransom:

Yes, but since it doesn't.... (going on the odd sense, not really disagreeing with you)..

If reducing the rear roll helps understeer, perhaps you are loosing camber control on the front? Do you have any pictures?

I thought about that, but while increasing front roll stiffness can do that counterintuitive thing due to improved camber control, removing the rear bar should have both strikes against it, right? Less overall roll resistance (so working backwards in terms of camber control) and a reduction in rear roll stiffness compared to front?

Or am I even confused about how confused I am?
May 6, 2011 3:30 p.m. bearmtnmartin New Reader

Jerry From LA wrote:

How much do you weigh personally? Seriously, losing ten pounds is like adding one horsepower. So if you have more to spare, there could be a tenth or so in that.....

Loosing weight; I'm not fat, but I could for sure slim down a bit. Funny though how I can lie on my back for 2 hours scraping off undercoat to go faster, but g o for a run? hmmmmm
May 6, 2011 3:35 p.m. bearmtnmartin New Reader

In response to Ransome and Alfadriver, I should say that removing the rear swaybar seemed to help me to stay in the lower grove when I wanted to. I should point out that I was playing with tire pressures too, but I attributed the decrease in understeer to my removing the rear bar. I could be wrong.
May 6, 2011 3:56 p.m. ransom Reader

In reply to bearmtnmartin:

Well, I confess to being pretty well confused by this time. I can't claim more for my observations than the books they came out of were entertaining, and the principles seem to have applied at autocrosses.

Now, looking at the flipside, your wedge and rear sway bar removal I would think would both help with keeping your inside rear tire hooked up on throttle. So, that's something else to pay attention to if you play with restoring the rear bar or removing wedge to reduce understeer.

One last piece of book-learnin' to toss out here: I think it's mid-corner (when the car has taken a set) that the sway bar and spring effects will be the most prominent.

I'm going to shut up now, even though I'm finding this an interesting puzzle. We've established that I'm uncertain at best, and several people have already pointed out that there's more lap time to be found in your driving than in this futzing around.
May 6, 2011 4:33 p.m. bearmtnmartin New Reader

I appreciate all the comments. Not sure what I will do for the next race day, but perhaps I will reconnect the rear bar for hotlaps and see how it feels. Alfadrivers comments regarding feel vs results is spot on actually. Fast cars are not supposed to be easy to drive. And the thing about a short track oval is that the straights are meaningless. Races are won in the turns and the trick is to get the car to turn left well at the expense of everything else. Some of the cars are just about undriveable on the straights.