Texas Mile FD
10-28-13, 03:48 PM
#1
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
Texas Mile FD
having raced for 22 seasons (SCCA NATS GT3) i arrived at the Texas Mile with nothing other than a "let's see what happens" outlook. i had traveled previously to one of the events a couple of years ago to get the lay of the land.
it sure did convince me that i wanted to be a part of it.
our prep was adequate but somewhat rushed.
we made an effort to arrive thursday when the gates opened. i figured there would be 20 to 40 cars at the gate given it was thursday. not quite. there were over 100 of the 220 entrants ready to roll. we tech'd and grabbed a paddock space.
we returned to the track friday at 6 am and finished the final details by 10. i headed to the grid for run one. the grid was 8 lines of 20 cars. time between runs was around 3 hours.
the Texas Mile seems to be well run and features a license classification based on speed, car and experience.
my car passed tech and it was qualified to 215 mph. the tech process was pretty good/serious as it should be.
since i was a newcomer with no runs i was limited to 165 on my first pass. go 166 and you do not get credit for the pass and do not move up to the next classification which is 199.
i eventually did get to the start line for my first pass and pulled off a clean start. my first gear is a 2.66 V the stock fd which is around 3.5 so it, being more like a normal second gear, can bog. no bog and an instant 9000 in first and second. shifted at 8800 in third and fourth.
so i am now looking at my tach in fifth and it is 6800 on the shift and starting to climb like crazy. the problem is 6900 is approx 165. oops.
i got off the gas and coasted. the 1/2 mile marker passed by. i pretty much coasted the last half mile and was timed at 152. (speedo not working)
i now move up to the next classification, 199 limit.
my motor seemed to have more vacuum at idle than before the run and i noticed my AFR was 10.42 thru the lights. conservative.
back in line for run two. i decided that i would go all out as the side wind had turned into a headwind and i figured i wouldn't bust out above 199.
this time i bogged the start and then hit all the gears well except for when i shifted to 4th the motor seemed to lose power.
ball game.
1430 miles one way and no clean full power run.
oh well.
i expect to be back next spring. i think the FD, with its small frontal area and low drag combined w a healthy 2 rotor can run 200 and would like to find out. (BTW, i did not run the rear wing...)
i will probably take the car to a drag strip before the spring event to log some 4th gear data.
next event we hope to have more of the ducks in a row.
two other rotary powered RX7s were at the event. a really clean black FD w a GT40 that should have run well and an FC w a GT35 that generally runs around 170.
next year. it was a blast.
howard
Last edited by Howard Coleman; 10-28-13 at 06:46 PM.
10-28-13, 05:09 PM
#4
Senior Member
Join Date: Jun 2004
Location: Canada
Posts: 442
Likes: 0
Received 0 Likes
on
0 Posts
So was the engine damaged or other failures. Good effort anyways. What tires do you run. I have seen some tires fail and that seams to be the worse thing that could happen. Engines are easy to fix lol.
) next year!!!
10-28-13, 06:55 PM
#7
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
"What tires do you run."
having watched the Hinson Corvette blow a rear tire at the 3/4 mile marker, do a half barrel roll, land on its roof, do another half roll and land on the wheels in a pile of fiberglass all from a blown rear tire i share your interest in and respect for tires at 200.
the Hinson Corvette was running drag tires w over 1000 hp and shredded a rear tire. rear corner goes down, diagonal front corner goes up. you do not want air under the car or it turns into an airplane. which it did.
result: no drag tires allowed going forward.
i had an hour conversation w my old racing buddy who is head of R&D at Tire Rack and as a result ended up w Michelin Pilot Sport Cup tires which are rated (Y). (Y) is a higher rating than Y. 265/35/18 F, 295/30/18 rear.
one of the areas we didn't get addressed was a scatter shield. it was the only safety issue on my mind. we had run the car at 8800 in fifth on the dyno w no problems but i guarantee you i will have a kevlar blanket between me and the drive train next time.
howard
having watched the Hinson Corvette blow a rear tire at the 3/4 mile marker, do a half barrel roll, land on its roof, do another half roll and land on the wheels in a pile of fiberglass all from a blown rear tire i share your interest in and respect for tires at 200.
the Hinson Corvette was running drag tires w over 1000 hp and shredded a rear tire. rear corner goes down, diagonal front corner goes up. you do not want air under the car or it turns into an airplane. which it did.
result: no drag tires allowed going forward.
i had an hour conversation w my old racing buddy who is head of R&D at Tire Rack and as a result ended up w Michelin Pilot Sport Cup tires which are rated (Y). (Y) is a higher rating than Y. 265/35/18 F, 295/30/18 rear.
one of the areas we didn't get addressed was a scatter shield. it was the only safety issue on my mind. we had run the car at 8800 in fifth on the dyno w no problems but i guarantee you i will have a kevlar blanket between me and the drive train next time.
howard
Trending Topics
10-29-13, 07:16 AM
#10
That is not what I was expecting nor hoping to read.
So this is an apex seal failure at best rich torque air fuel ratio for E85 with auxiliary methanol and water injection?
I wouldn't expect any other engine failure would cause total loss of power, other than that I have to guess some electronics failed.
10-29-13, 10:20 AM
#12
10.4 AFR is pretty rich for E85... I assume you were logging both of those runs?
Assuming it was an engine failure, what happened to your dual knock sensors? Not able to react fast enough? Did you have any other engine protection features setup on the ECU?
From what you wrote it sounds like you did not even really get into 5th gear which is where most of the load would be, seems odd to lose the motor on a 3rd/4th gear pull. You did not have any injector diffusers this time right?
Either way, that is unfortunate. I was looking forward to hearing your results as there are very few FD's competing in these events.
Assuming it was an engine failure, what happened to your dual knock sensors? Not able to react fast enough? Did you have any other engine protection features setup on the ECU?
From what you wrote it sounds like you did not even really get into 5th gear which is where most of the load would be, seems odd to lose the motor on a 3rd/4th gear pull. You did not have any injector diffusers this time right?
Either way, that is unfortunate. I was looking forward to hearing your results as there are very few FD's competing in these events.
10-29-13, 10:52 AM
#13
Yeah I'm very sorry to hear this .. I know howmuch it sucks I would really be interested in knowing what caused the blow if possible I think many of us would like to know . =(
I know howmuch it sucks driving 1200 miles to an event and having the engine blow .
I know howmuch it sucks driving 1200 miles to an event and having the engine blow .
10-29-13, 10:54 AM
#14
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
while i had my laptop onboard i was unable to get it logging as the bright sun obscured the screen and it was bolted to the floor. we had run the motor extensively in 4th and 5th on the dyno and all was well w re to the metrics. it almost seems like something weird happened like a blown fuel pump fuse or a vacuum line. i did a very brief look at the vacuum lines and they appear all in place.
while i have an active knock system we had not yet enabled it, and no, there are no diffusers in my engine.
most of november is dedicated to customer engines and i will revisit my car in december and probably trailer it back to BR for some dyno work and perhaps a EFR 9180. as soon as the snow melts we will do some datalogging in the quarter. i am certain we will discover what happened.
the Mile is addictive and the FD should be a killer.
howard
while i have an active knock system we had not yet enabled it, and no, there are no diffusers in my engine.
most of november is dedicated to customer engines and i will revisit my car in december and probably trailer it back to BR for some dyno work and perhaps a EFR 9180. as soon as the snow melts we will do some datalogging in the quarter. i am certain we will discover what happened.
the Mile is addictive and the FD should be a killer.
howard
10-29-13, 01:22 PM
#16
most ECUs have a threshhold command to start logging.
add in that some dynos do not have a loading feature it can be difficult to simulate real world loads so the AFRs might not have been as ideal as they seemed on the roller, but i doubt at 10.4 it was an issue of running lean, more likely ignition breakup from too much fuel as that is quite rich on ethanol.
add in that some dynos do not have a loading feature it can be difficult to simulate real world loads so the AFRs might not have been as ideal as they seemed on the roller, but i doubt at 10.4 it was an issue of running lean, more likely ignition breakup from too much fuel as that is quite rich on ethanol.
Last edited by RotaryEvolution; 10-29-13 at 01:26 PM.
10-31-13, 02:17 PM
#19
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
upon return from the Mile i called Luke, my long time tuner, and the first comment he made was check the fuel pump fuse...
i think it will be a simple matter to diagnose the cause of the fuse failure. my guess is a clogged pump filter. when Luke and i discussed switching to E85 he said the primary issue was that E85 acts like a cleaner in the tank and any rust or whatever ends up in the filter. he has had to clean a number of filters...
FWIW, the AFR at the end of my initial run was very similar to the tune. yes, it was rich but were are in unexplored territory with not much data. the car ran fine on the load dyno at that AFR.... and of course it would have run fine-er leaner. once we had made a few runs i could have easily auto-tuned it to a leaner AFR.
i think there was a brief period where the pump was still pumping but was outputting less than normal flow causing the motor to go lean. if the fuse had just popped it probably would have been similar to a fuel cut and we have had numerous fuel cuts on the dyno as part of the tuning process.
howard
i think it will be a simple matter to diagnose the cause of the fuse failure. my guess is a clogged pump filter. when Luke and i discussed switching to E85 he said the primary issue was that E85 acts like a cleaner in the tank and any rust or whatever ends up in the filter. he has had to clean a number of filters...
FWIW, the AFR at the end of my initial run was very similar to the tune. yes, it was rich but were are in unexplored territory with not much data. the car ran fine on the load dyno at that AFR.... and of course it would have run fine-er leaner. once we had made a few runs i could have easily auto-tuned it to a leaner AFR.
i think there was a brief period where the pump was still pumping but was outputting less than normal flow causing the motor to go lean. if the fuse had just popped it probably would have been similar to a fuel cut and we have had numerous fuel cuts on the dyno as part of the tuning process.
howard
10-31-13, 02:26 PM
#20
Wastegate John
iTrader: (13)
Join Date: Feb 2008
Location: Long Island NY 11746
Posts: 2,979
Likes: 0
Received 9 Likes
on
9 Posts
So you drove 2600 mile round trip and spent years preparing your car to not check a fuse when the engine died? You just put it on the trailer and did not check anything?
LOL
LOL
10-31-13, 02:40 PM
#21
i'm guessing the engine is done after the lean cycle under those loads, so popping in a new fuse probably wouldn't have changed much. but yeah i would have diagnosed it on the spot to see if the day could be salvaged.
and when it comes to pumps overkill is better, 30a fuse with paralell twin 30a relays even to a single pump. but no need to give further advice..
and when it comes to pumps overkill is better, 30a fuse with paralell twin 30a relays even to a single pump. but no need to give further advice..
Last edited by RotaryEvolution; 10-31-13 at 02:43 PM.
10-31-13, 03:05 PM
#22
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
"So you drove 2600 mile round trip and spent years preparing your car to not check a fuse when the engine died? You just put it on the trailer and did not check anything?"
maybe i didn't make myself clear... i knew the engine was history a couple of seconds into 4th gear.
"overkill is better, 30a fuse with paralell twin 30a relays even to a single pump."
appreciate the constructive advice... of course the key will be diagnosing why the fuse blew which will not be difficult.
howard
maybe i didn't make myself clear... i knew the engine was history a couple of seconds into 4th gear.
"overkill is better, 30a fuse with paralell twin 30a relays even to a single pump."
appreciate the constructive advice... of course the key will be diagnosing why the fuse blew which will not be difficult.
howard
10-31-13, 04:10 PM
#23
Hey Howard, I just found your thread. That really sucks to hear your luck. I tried looking on the Texas Mile's website after you told me you were going down there and couldn't fund any good results. I wish they could take a lesson from the SCCA and put up live timing results. Let me know if you need an extra set of hands this winter. I'd be glad to come up and help out and no doubt learn a trick or two. I'm working on finally getting mine back together. The motor you rebuilt is just sitting in the garage waiting on me to finish the assembly.
Adam
Adam
10-31-13, 04:32 PM
#24
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 416 Likes
on
252 Posts
"So you drove 2600 mile round trip and spent years preparing your car to not check a fuse when the engine died? You just put it on the trailer and did not check anything?"
maybe i didn't make myself clear... i knew the engine was history a couple of seconds into 4th gear.
"overkill is better, 30a fuse with paralell twin 30a relays even to a single pump."
appreciate the constructive advice... of course the key will be diagnosing why the fuse blew which will not be difficult.
howard
maybe i didn't make myself clear... i knew the engine was history a couple of seconds into 4th gear.
"overkill is better, 30a fuse with paralell twin 30a relays even to a single pump."
appreciate the constructive advice... of course the key will be diagnosing why the fuse blew which will not be difficult.
howard
Sometime the spot welds on the baffles come loose and bang against the fuel tree causing issues.
Good luck with the next run
10-31-13, 05:50 PM
#25
The fuse burn is expected. You fuse current rating is too small for a Walbro 416 using 13.5 volts let alone the 16.0 or 17.5 volts you talk about using, take a look at the manufacturer datasheet on that part. Also are you taking your Boost-a-pump out of spec? Apparently they have 20.0A and 40.0A models.
