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Posts posted by wd6681

  1. After a hub failure 2 hours into the Thompson 12 hour, I must ask. What do you guys run? How long? Repack or throw out?

    Also interested to see if anyone has had success with the wildwood hubs that previously seemed to be problematic.

    I did not realize that hubs were literally breaking like this, I thought the bearings were going bad. Now I see this is common.

    This was a repacked (new) timken with 26 hours of racing. Bearing was fine.



  2. 34 degrees sounds like a lot to you modern fast burn chamber guys, but nearly all the domestic v8s especially pre vortec sbc stuff is 35-42 degrees. Cylinder fill and burn speed is so much better on most 4v motors they seem to usually be in the low 30s. Look how much timing an m20 takes compared to an m50.

    You should be nervous about the problem, thankfully you have megasquirt so you can log some data and do some diagnostics. Do other cylinders show signs of preignition? What was the failure mode of the 2 cylinders?


  3. 7 hours ago, Team Infiniti said:

    Is this something new with no other changes?

    No, it has happened at the 2 race weekends the car has been run at. Miatas are new to me. Sounds like the general consensus is I am over thinking it.


    • Like 2
  4. No temp gauge. Not overfilling. It looks like according to spec 48psi is acceptable. It is more concerning that the psi is lower than that if a lower RPM which then makes me question its presence of air. Previously I ran a CJ4 rated sae30. At watkins glen I ran an SN rated sae30 to hopefully get greater anti foaming additives. If this is foaming/cavitation, it could not be solved with viscosity right? That will only mask the presence of the air in the oil.


  5. Noticing that our NA6 miata has 48psi of oil pressure when racing but 52psi (relief pressure) under caution (elevated RPM). I do not feel oil temp is the cause as the change appears immediate. When racing at 5500-7200rpm oil pressure reads 48psi; under caution 3500-4500rpm the oil pressure is back up at 52psi. My Concern is aerating or cavitating oil. Is this an Aeration problem and if so.

    -Problem with oil (SAE30, straight, non motorsports specific)

    -Oiling system (any known improvements?)



  6. My question is more relevant to my tow rig, or should I ever race a newer car. I am a loyal user of NGK copper plugs in everything. My vibe is the performance world agrees. My question pertains to using them in a modern vehicle. Other than shorter than OEM service life, what is everyone's experience with 'going backwards' and using copper plugs in a platinum or iridium OE application? I ran copper plugs in an LS with great success years ago. Wondering if anyone else has more experience with other COP systems.


  7. 10 hours ago, MoparBoyy said:

    great if you run the ACR version on a viper, for short periods of time, the compounds are not the same on the other sizes.  A focus team ran them who was pitted next to us, they just complained the whole race how bad the tires were.

    Are referring to the v720 as there is not an acr version of the v730. I am also assuming there is a difference between the v720 and v730 :)

  8. On 2/8/2021 at 9:57 PM, petawawarace said:

    I read an article from Amsoil that their Sycromesh 5W-30 is compatible and better than ATF for manual trans that don’t need the friction modifiers.  My Diff is a Torenson style so no clutch packs to worry about.   

    I wouldn’t think ATF is thinner than 5w-30?

    Older atfs are around the viscosity of 20w motor oil and newer atfs are thinner. For thin gearbox applications I have had luck with shell sprirax gxme

    • Like 1
  9. 1 hour ago, mender said:

    The engine would give up from oil starvation long before the turbo.


    I would say that managing heat is the main issue. 

    Right, what I mean to say is that the turbo could be experiencing starvation while the engine is not. I am told this is the primary advantage to a ball bearing turbo, it is more tolerant to oiling shortages.

  10. 1 hour ago, BollingerChump said:

    You joke, but I read a thread just this week by some SCCA road racers claiming that running a stickier than SM compound slick added a 1.5s+ per lap to their miata lap time at VIR.  They were serious...

    It would be really interesting to see what part cones from rolling resistance and what comes from temperature window. Naturally they go hand in hand as well as that rolling resistance energy goes into heat. Very interesting! Any idea if they were quoting best lap times or average?

  11. The 245 rt660 sounds promising. I would also consider a toyo r1r 225 on a 15x9. Many complain about wear, I agree about the first 3-4 32nds but following that wear is good. No where near a rs-4 but considerably better than a re71r. Clearly they would respond well to shaving (never tried it). The 225 on a 15x8 feels a bit like a bias ply, I feel the 15x9 would help a lot. They also have a flat tread like an rs-4 unlike the arched tread of an re71r. Hopefully that means little setup change. I have a cut section of re71r and r1r if you want some pictures. Summary is the r1r has harder sideway and softer tread plies. 

  12. 1 hour ago, LuckyKid said:

    I will try to grab my plots to show you if you need proof, but there is a real world speed difference.  We've tested Rivals vs. RS4s vs. RE71Rs (two different sizes) with multiple test days (we've spent several thousand dollars to do this).  The combined G-plots show that the RE71-Rs and Rival S's have more grip than the RS4 which you can physically feel.  its almost foolish to suggest otherwise if you've driven on the different compounds.

    My intention is not to dispell anything. Just bring some science to this; before the club takes away liberties based on what at this point is an opinion rather than multiple sources demonstrating a measurable difference in average speed. Generic seconds per lap cannot be taken seriously. We race on tracks that take a little over a minute to circulate and tracks that take well over 2 minutes. Average speed is the best way to compare. 

    Based on your collecting of data I am pretty sure you probably can access some form of average such as average of green laps for 1 driver.

    Excited to get some free data!!

    • Like 1

    Summary. As laps go up, rs-4 gets faster re71r and z3 slower (re71r moreso)

    Averages of the 7 laps:

    Z3: 50.36

    Re71r: 50.66

    Rs-4: 50.45

    I would also like to point out that the percentage difference between the best rs-4 lap and re71r lap would not yield the 2-4 seconds per lap people are throwing around for the 'cheater' tires.

    It is possible that the re71r responds better as a bolt on speed tire to a mediocre setup. A car could be set up to be fast on all of these. The teams beating you and me on Bridgestones would beat us on rs4s.


    • Like 1
  14. And I pay too much in taxes. Short of running a spec tire, what other viable options are there? I am pretty sure that a car maximized on RS-4s or RT615K+ that is well driven has potential to win a race. When it comes to keeping the field relatively even and budgets reasonable I do not see tires as the low hanging fruit. Handle these things through VPI, Swap, & part values.

  15. Could it be that the cast majority of teams complaining about tire widths and compounds have not maximized their setup to a tire size and construction? Larger tires are a compromise, different corning dynamics for lower straight line speed.

    Part of the appeal of the series is not just car spectrum but direction of development. I run a 205 for cost and speed reasons. 

    • Like 1
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