63 replies to this topic

[Zauskycop]

Both great topics and worthy of some time from a few of our experts...  

 

For question 1) Does the car need to go faster?  Are your lap times from start to finish of a session within /10th's of each other???  Where do you finish now?  What car, motor?  How much prep?

 

2) I don't swap them on the rim and it would be essentially free for me.  I do mark the tires and look for them to slip on the rim, that way I know when to rebalance..

I try to take the easy way out on this one.   I find that 95% of the tire movement happens on the rear rims.   So I will run 1 or 2 races, then switch sides on the rear tires and let them go back the other direction!   Has worked well for me.

[TJKearney]

I'm not usually a redneck, but when I am, I go full redneck.  I went redneck with MY Hoosier tire movement issues.  First: like Mike said, mark the tire/rim for baseline index.  I get significant movement on the rear tires as well.  Tires were mounted dry.  I first tried AquaNet, which helped quite a bit, but I still got movement.  I then devised a way to re-index the tire on the rim at home.  I break the bead with the shop press and a 2x4, then I ratchet strap the outside circumference of the tire to a tree in the backyard....tire/rim laying flat on ground at the base.  I then use a "rock bar" (a 5' steel bar used to dig rocks out of a hole) wrapped in a piece of pvc pipe to lever the wheel until the index marks line up again.  It's important to do outside so you can jam the rock bar into the dirt to get leverage.  Re-seat the bead and inflate.  Done.  Find a piece of grass to chew on and enjoy a cold mason jar of moonshine.

[DrDomm]

I'd really like to hear the top drivers opinions on "how to drive a Spec Miata", and the from the top prep shops "how to setup a Spec Miata".

 

So, driving style and setup philosophy.

[ManhattanM]

Many thanks to the fast guys for taking the time to share their wisdom.  We are very aware that the motor is only part of the performance equation, but as we havent yet made the investment in a pro motor I was hoping to get people's views on the longevity/running costs of a built engine.  For reference, we've spent the last 3 years running the stock engine (with FPR and timing wheel) that was in the car when we bought it, and our best estimate is that the prior owner put at least a couple hundred racing hours on it before our purchase.  In our three 5-6 weekend seasons, we havent had a single hiccup from the engine, touch wood.  We've so far focused on seat time, prep and setup, but in considering the next step we are trying to figure out:

 

1.  In general, how many hours should/could a pro motor (ex, East Street, Rossini, Ti Speed etc.) run before starting to lose significant (ie, more than 3-5%) power and needing a “freshening”?

 

2.  Is it worthwhile to freshen JUST a head, or is it more useful to always refresh head and block at the same time?

 

3.  Assuming head and block should be freshened, is there a benefit to sending the engine back to the original “builder”, or is this work doable “by owner” or maybe a local shop?

 

4.  Is a pro engine inherently less reliable/more finicky (beyond normal dyno tuning/FP adjustments for optimization)?

 

Thanks again for sharing your insights.

 

Armando

[DDSracer]

How do the experts roll off of the brakes? I've heard two versions.

1. come off of the brakes as fast as you can. 

2. Roll off slowly. Jackie stewart claims that he won most races because he rolled off of the brakes slower than the others. 

 

AB

[Rob Burgoon]

How do the experts roll off of the brakes? I've heard two versions.

1. come off of the brakes as fast as you can. 

2. Roll off slowly. Jackie stewart claims that he won most races because he rolled off of the brakes slower than the others. 

 

AB

 

The quality of the brake release makes a big difference when you're trail braking.

[Roger Caddell]

IMO (based on data), brake release is a critical area where most can improve. Abruptly going from negative 'braking' g's to positive 'acceleration' g's can result in the loss of grip and result in immediate under or oversteer and more importantly lower mid and exit speed.

 

The concept of a slower release of brake pressure must be tied to it happening slightly earlier to maximize the lap time saving/ higher speed benefits. Consistently higher exit speed is typically the goal. The additional benefit of being easier on the tires (and faster at the end of a race) is also important.

[davew]

The quality of the brake release makes a big difference when you're trail braking.

 

In general, Miatas do not like to be trail braked. There are always exceptions, but if you never ever trail brake you will be consistently faster than the guy who always trail brakes. Everything else being equal.

 

Brake in a straight line, down shift as late as possible, release the brake, turn the wheel, ease into the throttle to balance the car during cornering. The faster you can "ease" the better.

 

I may not be a fast driver, but that is what these cars, and most low hp cars, like.

 

Dave

[RussMcB]

Two more things I thought of:

1. I'm not yet clear about where to measure ride height.  Related: At my last race someone (who seemed to know what they were doing), stuck their hand in my wheelwell and said my ride height was about right, that there needs to be a finger width between the strut and bump stop.  Later in my garage I tried to do that but couldn't figure out where they were reaching in and feeling.
    
2. I may not be able to join the chat due to a conflict.  Any chance it can be viewed afterwards?

Thanks.

[Johnny D]

Two more things I thought of:

1. I'm not yet clear about where to measure ride height.  Related: At my last race someone (who seemed to know what they were doing), stuck their hand in my wheelwell and said my ride height was about right, that there needs to be a finger width between the strut and bump stop.  Later in my garage I tried to do that but couldn't figure out where they were reaching in and feeling.
    
2. I may not be able to join the chat due to a conflict.  Any chance it can be viewed afterwards?

Thanks.

Ya, about 5/8". Just like they said. Do you know where your bumpstop and strut are ?? you may need to turn the coil a bit. (on the ground)

Maybe take the fender off 1st time.

 

I think there was an attempt to copy it but didn't work last year.

Last one out erases/resets it basiclly, so if somebody stays, there's a foot in the door to get in.

J~

[Caveman-kwebb99]

Ya, about 5/8". Just like they said. Do you know where your bumpstop and strut are ?? you may need to turn the coil a bit. (on the ground)

Maybe take the fender off 1st time.

 

I think there was an attempt to copy it but didn't work last year.

Last one out erases/resets it basiclly, so if somebody stays, there's a foot in the door to get in.

J~

  Except in the country of California were it is very cool to have a lowrider Holms...  If you set the car right down on the BS you dont have to wait for weight transfer to get it on the BS's...  Oh yeah baby

[Johnny D]

  Except in the country of California were it is very cool to have a lowrider Holms...  If you set the car right down on the BS you dont have to wait for weight transfer to get it on the BS's...  Oh yeah baby

 Yes we can discuss riding on the BS or not, Go kart or boat handling, YMMV.

J~

[Caveman-kwebb99]

 Yes we can discuss riding on the BS or not, Go kart or boat handling, YMMV.

J~

  Maybe u can ask the importance of the 5/8" bs clearance on tuesday to satisfy your curiosity... see how many of the experts routinely run a car under 5/8 bs clearance.  there are a couple tracks it can work,, and i know of one old salt that drove like that everywhere, but he was the exception not the rule.  I know of 4 championships and several runnersup to the championship that has that much clearance...  As well as when I was in your earthquake ridden country I did not notice any front runners that were on the BS's  Ese.

[Rob Burgoon]

In general, Miatas do not like to be trail braked. There are always exceptions, but if you never ever trail brake you will be consistently faster than the guy who always trail brakes. Everything else being equal.

 

Brake in a straight line, down shift as late as possible, release the brake, turn the wheel, ease into the throttle to balance the car during cornering. The faster you can "ease" the better.

 

I may not be a fast driver, but that is what these cars, and most low hp cars, like.

 

Dave

 

Sometimes the track layout tries to insist.  

[FTodaro]

In general, Miatas do not like to be trail braked. There are always exceptions, but if you never ever trail brake you will be consistently faster than the guy who always trail brakes. Everything else being equal.

 

Brake in a straight line, down shift as late as possible, release the brake, turn the wheel, ease into the throttle to balance the car during cornering. The faster you can "ease" the better.

 

I may not be a fast driver, but that is what these cars, and most low hp cars, like.

 

Dave

would you say the same thing for a left foot braker? on a non down shift corner.

[glove]

This Ask the Experts chatroom sounds great. Has the date and time been finalized?

[Todd Lamb]

DDS - excellent question...looking forward to diving into that question on the chat. As Roger said, that's where the majority of the time is to be gained once you've got the basics figured out.

[RacerX]

   "...I may not be able to join the chat due to a conflict.  Any chance it can be viewed afterwards?"

 

 

Same for me and I too would be interested in viewing later if available

[Brandon]

What URL to participate/watch/learn?

[Rob Burgoon]

"How large of an impact does rear toe in have on straight line drag?"