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speedracer

speedracer 1990 Miata

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Just to catch everyone up on my Miata .   The new quick connect steering wheel was installed and I had the steering rack depowered.  That was an excellent modification which allows me in and out of the car with much less pain. 
 

The fans would not turn on so it needed a new sensor on top of the thermostat.   
 

So far it will not go over 87 mph. My son has a theory that if I hit 88 the flux capacitor will kick in.  So if you are following me and suddenly I vanish it is that I have gone back to the future.

Efforts to increase top speed discovered that at some point the exhaust system ate a catalytic converter. That resulted in installation of a new exhaust system.

The car survived all weekend so I signed up for another track day.

it will still not go over 87 so I am exploring other options to get it to go faster.

However before I endulge in go fast parts the car needs new brakes.   So  as with all track cars the budget has been thrown out of the window as I continue to throw money at the car hoping that at some point it will become a fast and reliable HPDE car. 

 

 

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The Miata is back in the shop this morning for new brakes and some new sway bars.    I am looking forward to an additional step forward in confidence with the car during the next HPDE event.   Nothing like new brakes to boost your confidence hammering the brakes before a low speed corner. 

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For the second time in my ownership the Miata made all 8 sessions of my HPDE event.   The new brakes worked  perfectly and I was generally more focused on driving and less worried about the car.  I had one off but was able to navigate back to the track under the cars own power.     Of particular note this car has very little power and consequently some of the high speed turns required little or no braking.  It much more like driving go cart at track 21 where you focus on saving every single ounce of momentum in every corner and resign yourself to little or no acceleration.    It is a sad state of affairs when the 1.8 liter miatas are sorry for you because they pull away on the straights.    My next purchase will be to replace my 15 year old struts and bump stops. 

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I replaced the koni yellows with a fresh set of penski based spec Miata coil overs.   The first track day indicated that I needed to make a few more small adjustments. 

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In the world of under powered Miata cars I seem to have a particularly underpowered car.   I had a compression test completed  and it was fine.   Perhaps my Miata needs an emotional support lawn mower to help it feel better about itself.   

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It's all about minimum corner speed in these.  If you can get that up, it will seem like you have more power.

Also, harmonic dampeners go bad and can give an erroneous timing indication.  Easy enough to confirm that "0" is really TDC on #1.  If you erroneously retarded your timing, then you really will have a particularly underpowered car.  Most of us advance the timing 2-4 degrees.

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Lots of small things add up to more power on these cars.  fuel pressure, MAF 'calibration', correct oil viscosity, etc.    if you're running 10w40 cuz you think old engines need thick oil, then you're losing several HP to pumping loss on the oil.    stuff like that.

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Thank you for the ideas.   To be specific, when I put the car together I changed the timing belt.   I had difficulty getting the new belt installed correctly. Many years later I finally got around to evaluating why my car seemed to have such low power. I wanted to start with the basics.   So I had a compression check done, I had an extra in line fuel filter removed. Then the timing was checked.   It was advanced 20 degrees.  That could be the reason that I have no top end power.   I am glad I have been running super unleaded so that probably kept my engine from self destructing.  The timing has been adjusted back into the 14 degrees advanced range which is still above the 10 degrees stock.   I am running 40 weight oil because when I got off track and the engine  was hot it was showing very low oil pressure and making some very unpleasant noises.   So even if 40 weight is slowing me down I am okay with that.  The car is a work in progress. My target is a safe HPDE beater to get some track time and enjoy working on my driving skills. Next track day in a few weeks! We will see if I can get to 100 mph.

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on that note, is the cam timing (via the timing belt) set properly?
Ignition timing is completely different than cam timing.   If you're off a tooth, the car will have very low power but still run.

 

How low was the oil pressure when you got off track?   I run 5w20 (redline 20wt race oil) in my FRS..  Cold startup pressure at idle is 120psi, but when hot, it's 8-12psi.   eeeek.   but that's how they work and it's normal.  YMMV, but you *may* be worrying about something that's a non issue.

 

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I went back and read the whole thread.   I am close to my objective of having a reliable HPDE car.   The last several track days I have made all 8 sessions for the weekend.    While I am still making adjustments to to the car I have transitioned back to focus on my driving. 

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13 minutes ago, speedracer said:

It has taken me about 2 years to fix all the problems Hastarock identified in about 10 minutes. 

I totally know that feeling.  I'm also at the point that I've forgotten more about cars than I know now.  spent 3hrs last night diagnosing and replacing a fuel pump that died after running the car out of gas.  (to my credit, the car has 2 fuel pumps and I could hear the surge tank pump running loudly and never heard the other one so I couldn't tell if it was alive or dead until the surge pump wouldn't prime anymore..)

Once I diagnosed the problem, it took me 5 min to pull the spare out of my parts car because the interior was bare, but 2hrs to replace into my race car.  because fixed back seat and roll cage,  I had to climb into the back seat area thru the cage and basically stand on my head while I was elbow-deep in the fuel tank to get the tubing hooked up.  Had I just taken 10 min to remove the seat, 

THEN the damn car wouldn't reprime and start cause the battery was too weak from me trying to diagnose the other fuel pump problem.   

then I freaked out when there were a dozen ECU codes once I got the car started on jack stands and the rear wheels spinning while fronts were not threw the ABS controller and traction control into fits.  

on and on and on.  

all cause I ran it out of gas fiddling with the tune in the garage.

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For the time being I have resorted to using a trusted mechanic that knows what he is doing to keep the car on the track.   I know this may be considered cheating . However, I have poured enough of my time and sweat into this car . It just needs to run and drive safely so I can have some fun. 

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On 5/27/2022 at 5:08 PM, speedracer said:

For the time being I have resorted to using a trusted mechanic that knows what he is doing to keep the car on the track.   I know this may be considered cheating . However, I have poured enough of my time and sweat into this car . It just needs to run and drive safely so I can have some fun. 

I absolutely know that feeling.  I don't have the time to deal with minutia, but the one guy in Houston that tunes these cars is out in Sealy- 1.5hr drive.  so by the time I trailer the car over there, talk for 2hrs and wander around the shop, etc.. I lose >6hrs of productivity.  since he's only open during normal working hours, that's 12hrs total for two round trips on the car so I usually just do everything I can myself and stack up the big things for one or two trips a year to the shop.  no ideal, but given the amount of hours I drive it (less than 20hrs/yr), it's not like it's missing much.

The other side of that coin is knowing what and how to adjust, and having the right tools to do it.  I've slowly collected everything I need to do proper race alignments and corner weighting so I have all the tools and know HOW to turn the knobs, but which direction to turn them is the science I haven't yet learned and need some skilled help to get there.  I expect to hire a teacher at some point for that, as watching interweb videos only gets you so far vs. real world hands on experience when my car is doing something funky on the scales or something isn't just quite with the numbers.  

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The mechanic I am using is a 10 minute flat tow from my house .   Usually I drop it off before work and pick it up at lunch time.   Very easy.    As I continue on my Miata journey I will start to make a few adjustments at the track with his recommendations. 

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33 minutes ago, speedracer said:

The mechanic I am using is a 10 minute flat tow from my house .   Usually I drop it off before work and pick it up at lunch time.   Very easy.    As I continue on my Miata journey I will start to make a few adjustments at the track with his recommendations. 

You are very fortunate on that regard!  My chassis guy is about 20 min away in Angleton, but my engine tuner is in Sealy. (I'm about 10 min north of MSRH in Alvin area...)   drawbacks to living in the country.

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