1 2
Ovid_and_Flem
Ovid_and_Flem HalfDork
7/19/17 7:44 p.m.

In reply to ghackenberg:

Looking good...are you building it to a specific class rules?

ghackenberg
ghackenberg New Reader
8/14/17 9:16 p.m.

Question for you guys: I have a set of 14x6 stock miata wheels. Can't find any good performance tires for that wheel size. Do I need to go up to 15 inch?

Detailed update on the car coming soon, but it runs now!

Robbie
Robbie UberDork
8/14/17 9:44 p.m.

Yeah, much better tire selection in 15. There is an ad on the for sale subforum for some sweet tires that could come attached to some 15x10s.

But you also probably don't need to go THAT big.

alfadriver
alfadriver MegaDork
8/15/17 6:40 a.m.

Man, have times changed. I looked at Tire Rack thinking that there was still some good 14" options- while there may be more- Kuhmo does not have any, Hoosier has a 225 wide one (a bit too much, but perhaps), and Hankook has a 205 wide 14" tire. https://www.tirerack.com/tires/tires.jsp?tireMake=Hankook&tireModel=Ventus+Z214

Even with that available, I, too would lean toward the 15" Hoosier A7.

hobiercr
hobiercr Dork
8/15/17 10:11 a.m.
spin_out
spin_out HalfDork
8/15/17 2:54 p.m.

We are bringing a Miata and a little Tire shopping lead us to 15" rims. We really did not see an ideal tire in the 14" size. We only found the Hoosier in the R7 not the autocross A7 version. 15" rims really open up your tire selection. Tires are important.

ghackenberg
ghackenberg New Reader
8/15/17 5:14 p.m.

Awesome, thanks! I'll start searching for some 15'' rims.

ghackenberg
ghackenberg New Reader
9/3/17 1:06 p.m.

I just transported the car back to campus last week. Our science building is letting us use part of their loading dock to work until the race.

Untitled

Untitled

This week, I have a set of 15 inch OEM wheels coming in as well as a cold air intake system.

I have a cobra suzuka seat that I got used and it didn't come with mounting brackets. What do you guys suggest? Should I buy a pair of side mount brackets and modify them to fit, or should I just fabricate them?

Untitled

Students are coming back to campus this week, so we'll finally have the full team here to work!

stafford1500
stafford1500 HalfDork
9/4/17 6:49 a.m.

Fabricating is cheaper in $ but not in time...

ghackenberg
ghackenberg New Reader
10/2/17 3:08 p.m.

Had our first test day at a local autocross last weekend.  The car was great for the first 5 runs, but wouldn't start for the 6th. 

It has some trouble starting after sitting for a few days.  Rough idle when first starting but goes away within a few seconds.  A lot of engine vibration on the last run before it died.  It was really hot at the autocross.  Once I got it back to campus, it started and ran fine the next day.  Code reader shows nothing abnormal. 

Could this be a coil pack problem without a code?  Other ideas?

Ovid_and_Flem
Ovid_and_Flem Dork
10/2/17 4:39 p.m.

When you say it doesn't start, do you mean won't turn over or will it turnover but not start?

ghackenberg
ghackenberg New Reader
10/3/17 6:05 p.m.

In reply to Ovid_and_Flem :

Turned over but wouldn't start.  But that was just at the autocross last weekend, it starts just fine now

Ovid_and_Flem
Ovid_and_Flem Dork
10/3/17 6:12 p.m.

In reply to ghackenberg :

does it seem to be heat related?  I.e., does it start fine when it's not warm?

 

​​​​​​ when will your team be arriving in Gainesville?

GTXVette
GTXVette Dork
10/3/17 6:22 p.m.

Take it to the local Test and Tune at the closest Drag Strip. or another autoX ,  Most are on a Thurs./Fri./Sat. run it 5 times Back to Back, then shut it off and see If the problem comes back..... but just checking for Heat Soak is Half the prob. Correcting the Cause is the deal,  Too Hot Engine /Cooling System / Fuel Pressure or Pump Issue. Get it really Hot, Or if you can use the Back lot of the School(tell Security) go burn it down a bit,   shut it off ,wait a few mins. and try a re start If it Cranks go out and do it again.

ghackenberg
ghackenberg New Reader
10/3/17 6:33 p.m.

It does seem exacerbated by heat, although I did notice starting problems/vibrations the week leading up to the autocross.  

I will try to run it hard this weekend and see if the problem comes back.  

This is really my last weekend to devote all my time to the car before the race so I'm hoping I can at least diagnose the issue.  I wish I took a video at the autocross, but the guys there all thought it was a coil pack problem.  

GTXVette
GTXVette Dork
10/3/17 6:47 p.m.

they can Break down due to heat. If mounted to the engine Move it,or get air to it . do you think the roughness on start May be Timing, too much advance can make it feel like its firing too soon (it is) I don't know your Ign. system but starting advance can be very little compaired to running advance .  5-15 deg. to start but 10-15-18 at a fast Idle,and I don't know Mazda's but High RPM should be mid 30's. 

Jerry From LA
Jerry From LA SuperDork
10/3/17 7:03 p.m.

A bad coil pack can also show up like a heat-related problem.  Often, they will be fine until you run them a certain length of time and a hot running engine will shorten that time.  Run some tests on each pack relating to resistance between low and high tension leads, etc.  The specs should be online or in a manual somewhere.  Also, get down to the bottom of that hot running engine issue.  A good coolant flush may help with a distilled water/ water wetter fill.    In your neck of the woods, tap water would probably do if you're close on budget.  Check if your rad cap holds pressure as well.  Make sure your water pump isn't leaking from the "weep hole," which would bleed pressure as well as losing coolant.

 

ghackenberg
ghackenberg New Reader
10/3/17 7:09 p.m.

Awesome, thanks for the ideas guys!

 

Woody
Woody MegaDork
10/3/17 7:32 p.m.

I would start by checking your timing, because that doesn't cost anything. If that's where it should be, take off the valve cover and make sure the timing belt isn't stretched. I had a 2000 Miata that had a rough idle and was a frequent hard starter. Both issues went away after I replaced the 15 year old timing belt.

Also, keep an eye on the short spark wire that's closest to the firewall. I've had those pull off the spark plug on more than one Miata.

Are you planning to take the car to this year's Challenge?

ghackenberg
ghackenberg New Reader
10/18/17 8:10 p.m.

Last minute build book questions for you challengers.  

  • How do I account for materials that I already had and used to fabricate parts?  For example: scrap steel for seat brackets, muffler and exhaust tubes cut off an old car, sheet of lexan left over from another project.  
  • How detailed does the budget have to be?  Should I include random nuts and bolts that I bought?
  • Any other tips for layout?  
Tom Suddard
Tom Suddard Digital Experience Director
10/18/17 8:21 p.m.

Materials you already had go in as their fair market value. You have to add every single little nut and bolt you bought. 

 

Theres a rubric for build book layout—you’ll find it in the challenge rules at GRMChallenge.com. 

GTXVette
GTXVette Dork
10/19/17 8:55 a.m.

PS, don't shoot your foot off here.  that muffler and pipe isn't worth anymore than Scrap money if it's used and that's FMV. the lexan is a Portion of a sheet i must guess and only the portion you use needs to be considered so figure a PART of a Half sheet,  to make the money limit you have to be Tight on your Guesstimate not Generous. but don't let me lead you astray.

Woody
Woody MegaDork
10/19/17 9:06 a.m.

On a side note: 

If you find yourself shopping for a new nickname at the Challenge, Niko Häckenberg would be an excellent choice.

Woody
Woody MegaDork
10/19/17 9:38 a.m.

Mika Häkkiberg would also work...

1 2
Our Preferred Partners
a3Y8XjgwbhyescofJWNM41mV3wdBe4Fe4XfEB5TE5AtXMG4g0swn5o5O1orfqIxp