turbo reliability on track
#141
I'll take some educated guesses at some of the mistakes illeniummx5 made. Mistakes myself and everyone else here has made at some point. Willing to bet his team made at least 75% of these throughout development and still had 25% when they finally threw in the towel
Stuff Miata track turbo guys do wrong
Stuff Miata track turbo guys do wrong
- No hood vents
- Hood vents in the wrong location, i.e behind #3 cylinder
- No full coverage undertray
- Radiator core not 100% sealed for air leakage around it
- No reroute
- #6 or #5 plugs
- Stock coils
- NA batch fire ignition
- NA6 batch fuel
- Pump gas of 92 or lower octane
- Non-Inconel manifold studs
- OTS BEGI or FM manifold w/o turbo support brace
- OEM Garrett internal wastegate and >10psi instead of VTA
- Too small VTA BOV
- Intake pipes without beads
- Intake pipes held on with ordinary worm drive hose clamps
- Throttle plate not epoxied
- Solid motor mounts broke other stuff on car
- OEM diff mounts - broken exhaust
- No V-Band in DP
- OEM Rods
- OEM pistons
- OEM oil pump
- No clutch bypass for starting leading to toasted thrust bearings
- No oil cooler
- No trans cooler
- No diff cooler
- 5 speed transmission (went through at least four I bet)
- Rubber lines for turbo oil and/or coolant
- Restrictive tube/Fin I/C from big name American company instead of superior Chinese Bar/Plate off ebay (who knew)
- Piggy back ECU
- >13psi with NA cam/crank angle sensor + ragged edge tune = det
- No WB02
- WB02 in wrong place
- No EGT
- Coolant temp sensor at front of head
- Heater bypass w/o restrictor
- OEM 16psi rad cap instead of 19psi Koyo/Stant
- Too few/misaligned exhaust hangers = cracked DP
- Bad welds, cracked DP or exhaust
- 5th injector in manifold
- RX7 460cc injectors
- RC engineering injectors
- No det cans used during dyno tuning
- Boost turned up after dyno, then raced
- Boost turned up way past highest efficiency island on compressor map
- Zero safeties built in to ECU (overboost,EGT,WB02,coolant pressure etc)
- Insufficient heat shielding for heater hoses, master cylinder, trans tunnel
- More than one change in intake pipe cross section dimension between compressor-I/C or I/C- TB.
- Under drive pulleys
- Road tune only for WOT/peak boost only (no steady state part throttle dyno tune)
- $25 junkyard turbos
- Non-water cooled turbo
- Koni yellows with GC coilovers
- Spec Miata suspension
- OEM rubber suspension bushings
- NA6 diff
- Open diff
- more rear camber than front
- Anything less than 9" wheels
- 205/50/15's
- Zero front aero but tons of drag/lift inducing cooling holes in vain attempt to stop overheating
- No wing
- No hard top
- Bolt in cage
- NA8 brakes with Hawk Blues
- OEM bone stock hubs
- OEM end links
- A/C components still in car
- >2400lb comp weight
Stuff Miata track turbo guys do wrong
- Pump gas of 92 or lower octane
- OEM Garrett internal wastegate and >10psi instead of VTA
- Throttle plate not epoxied
- No trans cooler
- No diff cooler
- >13psi with NA cam/crank angle sensor + ragged edge tune = det
- No EGT
- RC engineering injectors
- No det cans used during dyno tuning
- Bolt in cage (Actually its a Hard dog roll bar with door bars)
- >2400lb comp weight
#145
Bob
#147
From what I have seen it is an RPM related thing. Guys frequently over 7200 rpm are the ones braking throttles. one guy here making 170 hp out of a naturally aspirated 1.6l regularly spinning to 8000 rpm is constantly braking throttle plates. I've never broke one. My car is a mid-range torque monster and the torque falls off past 7000 rpm so I shift. He has also broken all sorts of weird stuff due to vibration including the oil pressure sender cracking and falling off the side of the block he is even running stock engine mounts.
Bob
Bob
Then, a couple weekends ago at Buttonwillow, it blew the hell up.
Mind you, the death blow wasn't due to cyl #1. No, it turned out that cyl #3 was pinging like crazy. So much that it eroded the top ringland down to the ring and eroded the head until the head gasket blew. This severe det was not once heard on the dyno (or while racing, which is no surprise - earplugs and helmet). BTW cyl #1 looked like the surface of the moon.
But even cyl #3 wasn't the final nail in the coffin. We kept running it after JB Welding the head & replacing the head gasket. Finally, after a few more hours of racing, cyl #2 punched its rod thru the block. Probably water in the coolant during the head gasket swap resulted in a spun a bearing. Haven't done a postmortem yet.
So, yeah, this just reinforces that these are thrashy, coarse, ping-prone, yet tough little engines.
#148
mkturbo.com
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Happened to our 1.6 ghettocharged lemons car too. The screw head bounced around in cyl #1 for about 20 minutes until it finally shat out through the exhaust valve. Then we ran the engine for another half dozen races. It ran like nothing wrong ever happened.
Then, a couple weekends ago at Buttonwillow, it blew the hell up.
Mind you, the death blow wasn't due to cyl #1. No, it turned out that cyl #3 was pinging like crazy. So much that it eroded the top ringland down to the ring and eroded the head until the head gasket blew. This severe det was not once heard on the dyno (or while racing, which is no surprise - earplugs and helmet). BTW cyl #1 looked like the surface of the moon.
But even cyl #3 wasn't the final nail in the coffin. We kept running it after JB Welding the head & replacing the head gasket. Finally, after a few more hours of racing, cyl #2 punched its rod thru the block. Probably water in the coolant during the head gasket swap resulted in a spun a bearing. Haven't done a postmortem yet.
So, yeah, this just reinforces that these are thrashy, coarse, ping-prone, yet tough little engines.
Then, a couple weekends ago at Buttonwillow, it blew the hell up.
Mind you, the death blow wasn't due to cyl #1. No, it turned out that cyl #3 was pinging like crazy. So much that it eroded the top ringland down to the ring and eroded the head until the head gasket blew. This severe det was not once heard on the dyno (or while racing, which is no surprise - earplugs and helmet). BTW cyl #1 looked like the surface of the moon.
But even cyl #3 wasn't the final nail in the coffin. We kept running it after JB Welding the head & replacing the head gasket. Finally, after a few more hours of racing, cyl #2 punched its rod thru the block. Probably water in the coolant during the head gasket swap resulted in a spun a bearing. Haven't done a postmortem yet.
So, yeah, this just reinforces that these are thrashy, coarse, ping-prone, yet tough little engines.
#154
I think that list is more of compilation of things to consider. but it certainly seems like they apply at different stages, rather than on any FI'd miata. Not to mention the list is for a track car. I didn't even know anyone here ran trans/diff. coolers. I would like to read the write-up/discussion on that.
#155
The important thing is to be aware of all the pitfalls and don't be tempted to push too far without monitoring how close to the edge you are. The edge is of course a moving target depending on what things on the list you haven't fixed yet.
A poor tune is of course a problem already at 200whp, but many of the other things are not so critical at that level.
You will get more driving done with a "balanced" car at a decent level than a half-built monster that still have a couple of years in the garage until it's finished.
A noob question that I think is on topic (and might elevate the reliability discussion a bit).
Are there any different concerns sprint vs endurance for a Turbo Miata than for a non-turbo one?
A high strung NA engine must also be decently built to withstand a 24h race but are there anything special to think of for Turbo (that you would not notice in a 30-60 min feature race)?
For argument sake e.g. 110bhp/liter NA vs 200bhp/liter Turbo.
#156
Tour de Franzia
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I'm somewhat inclined to think that if the engine will survive a 30-minute sprint on the track like we run in TT, the engine will make it through the race. I'd be more concerned with trans and rear end fatigue, brakes at the 12-hour mark, and aside from that I don't have the experience to know much of anything on the subject.
#157
mkturbo.com
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I don't race my car, but I recently chased a Panoz for about 45-minutes in 103*f heat. Water stayed under 200*f and oil below 235*f, I was really surprised. I also was abel to wring sweat out of my seat-liner, lol. By no means do I think my car would make it through a 6-hour enduro.
I'm somewhat inclined to think that if the engine will survive a 30-minute sprint on the track like we run in TT, the engine will make it through the race. I'd be more concerned with trans and rear end fatigue, brakes at the 12-hour mark, and aside from that I don't have the experience to know much of anything on the subject.
I'm somewhat inclined to think that if the engine will survive a 30-minute sprint on the track like we run in TT, the engine will make it through the race. I'd be more concerned with trans and rear end fatigue, brakes at the 12-hour mark, and aside from that I don't have the experience to know much of anything on the subject.
#160
The list is a collection of all known FI Miata issues. it doesn't mean you need all the mods listed. The list doesn't distinguish between:
150whp turbo or 400whp turbo
20 minutes HPDE or 3 hours race
driver who is 10 seconds above or a driver who is 10 seconds below SM record.
obviously if you are running 150whp turbo in 20 minutes HPDE going 10 seconds slower than SM record, I am sure you do not need ANY of the stuff on the list. On the other hand, if you are Savington in his 350whp, you will need everything on that list to survive a 3 hours enduro race.
150whp turbo or 400whp turbo
20 minutes HPDE or 3 hours race
driver who is 10 seconds above or a driver who is 10 seconds below SM record.
obviously if you are running 150whp turbo in 20 minutes HPDE going 10 seconds slower than SM record, I am sure you do not need ANY of the stuff on the list. On the other hand, if you are Savington in his 350whp, you will need everything on that list to survive a 3 hours enduro race.