Longevity of high HP motors?
10-04-10, 01:39 PM
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Longevity of high HP motors?
Hey all...been thinking for a few months about getting another FD and I'm considering a few cars. I'm wondering for those out there that are pushing 400+ ponies on your motor (stock internals or ported) what is the best durability you've had with your own big pony engine?
Common sense says more ponies, less engine life. I should qualify that, more ponies, and driven hard using those ponies I'd say the CW says shortened engine life.
As an aside, for those running water/meth injection have you fried your motor while on this set-up?
To me the only way to have a 7 is with a wankel...this is a no piston car! But to each his own. But these darn rotaries seem to blow quite randomly, as we know all too well.
Common sense says more ponies, less engine life. I should qualify that, more ponies, and driven hard using those ponies I'd say the CW says shortened engine life.
As an aside, for those running water/meth injection have you fried your motor while on this set-up?
To me the only way to have a 7 is with a wankel...this is a no piston car! But to each his own. But these darn rotaries seem to blow quite randomly, as we know all too well.
10-04-10, 03:23 PM
#2
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high HP rotary and durability can only be made reliable by two thing's water/meth injection and proper tuning by a rotary shop. read Howard Colemans water injection post.
10-04-10, 03:23 PM
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There's a LOT of info on these forums on how to build an RX-7 with a high degree of reliability. The threads should be easily accessible via stickies.
10-04-10, 03:54 PM
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I should clarify...I'm looking to see how many miles you guys have gone on a high HP motor before you've blown it up.
Or if it's not blown, how many miles have you put on your big pony motor.
Or if it's not blown, how many miles have you put on your big pony motor.
10-04-10, 03:57 PM
#5
depends on how long you think is a long engine life for a rotary is. 30k is easily doable, most don't usually pass the 50k mark before something takes out the engine due to variances in the fuel system without regular tuning. i've had 450WHP engines go 30k only to have fuel system issues kill the motor but not any really more than that so far. it has to do a little with luck and alot to do with monitoring AFRs. little things like pre-mixing fuel and auxiliary injection help keep the motor together longer.
my personal car has about 60k miles on it at ~325 WHP, for most of those miles it was around 300 however. i try not to go too far with it all at once knowing that the further you go, the more perfect the tune has to be ALL of the time. course my DD is an FC but there is little difference between an FC and FD once you go single.
my personal car has about 60k miles on it at ~325 WHP, for most of those miles it was around 300 however. i try not to go too far with it all at once knowing that the further you go, the more perfect the tune has to be ALL of the time. course my DD is an FC but there is little difference between an FC and FD once you go single.
10-04-10, 04:55 PM
#6
Figure 20-40k if things go well, or 2-10k if things don't go so well. And as Karack was saying, like any heavily modified car it's pretty much a countdown until you have some kind of unexpected catastrophic failure.
With the amount you will want to drive it though that still works out to years of ownership. You'd be hard pressed to find anyone who puts more than 10k miles a year on any kind of heavily modified car, rotary or otherwise.
I know that sounds really low in terms of miles. Well I'll tell you one thing--a heavily modifed Rx-7 is not a C6 Z06. And by that I mean that a C6 Z06 is a modern car with a warranty, good A/C, traction control, and decent amount of comfort for a "hardcore" model. You don't want to drive a heavily modified FD every day. They're dangerous/hard to control, a lot of people find them cramped and uncomfortable, and they have barely any cargo space. And like any other car with that kind of power level, if you regularly enjoy that power you'll be getting crap gas mileage.
With the amount you will want to drive it though that still works out to years of ownership. You'd be hard pressed to find anyone who puts more than 10k miles a year on any kind of heavily modified car, rotary or otherwise.
I know that sounds really low in terms of miles. Well I'll tell you one thing--a heavily modifed Rx-7 is not a C6 Z06. And by that I mean that a C6 Z06 is a modern car with a warranty, good A/C, traction control, and decent amount of comfort for a "hardcore" model. You don't want to drive a heavily modified FD every day. They're dangerous/hard to control, a lot of people find them cramped and uncomfortable, and they have barely any cargo space. And like any other car with that kind of power level, if you regularly enjoy that power you'll be getting crap gas mileage.
10-04-10, 05:58 PM
#8
that is true, you can get decent gas mileage so long as you have a good low boost tune. if you're pig rich once you go past the 0"Hg thershhold your mileage can go south very quick. my car for example gets about 23.5mpg but gets pretty crappy in and around town, the bigger your turbo is to get that kind of power the more difficult it is to get a conservative map(gas mileage wise).
10-04-10, 08:55 PM
#9
I know of a local fd that had a rebuild at 103,000. Engine was built by rotary performance and is a street port with 3mm apex seals. Sequential factory twin turbos, PFC, full exhaust running 12psi. I'm suspecting this engine is making somewhere around 330rwhp. The car currently has over 200k on the same engine and still pulls good vacuum. It's all about the tuning and running this small displacement engine with-in it's limits. Also to those that think 3mm apex seals are a waste, this proves otherwise.
10-04-10, 11:38 PM
#10
EDIT: oh yeah, I managed to get 28 mpg on one tank of gas a while ago, BUT I deliberately did not boost and it was very warm outside (motor needs more fuel when it's cold). More often, with a heavy foot and lots of street driving it's like 15-20 mpg.
10-04-10, 11:50 PM
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of course, "high horsepower" is a relative term, anything over 250 rwhp is "very high" for a 1.3 L in my book
10-05-10, 12:20 AM
#12
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My last engine made 420 rwhp over the course of 6 years and ~20k miles. I sold it still running and with 100+ psi compression on all faces.
Current engine made 487 at 20 psi and it's seen as high as 22 psi on the street on 93 octane and Aquamist water injection. I'd have to check my records but I believe the engine has almost 8k miles on it now. Two DGRR trips and three road race events. Zero problems.
There isn't a magic formula to all of this, it just takes the right parts, attention to detail, and a willingness to not corners. A damn good tuner helps too
Current engine made 487 at 20 psi and it's seen as high as 22 psi on the street on 93 octane and Aquamist water injection. I'd have to check my records but I believe the engine has almost 8k miles on it now. Two DGRR trips and three road race events. Zero problems.
There isn't a magic formula to all of this, it just takes the right parts, attention to detail, and a willingness to not corners. A damn good tuner helps too
10-05-10, 07:04 AM
#13
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the 13B is 1.3 liters and equates to a 2.6 liter (4 cycle) piston engine because the rotary is a 2 cycle motor. you get a power event each time a combustion chamber (in the face of the rotor) passes the sparkplug. no bye week every other stroke like a piston engine... this increases the internal heat V a piston engine.
you have effectively 159 cubic inches. highly tuned factory street cars... turbo'd/supercharged, like the $117,000 ZR1 make 1.68 FLYWHEEL hp per cubic inch.
a 400 rwhp FD is making 460 FW hp or 2.89 hp per cubic inch. and most consider a 400 FD a medium range app.
we are in the deep end of the pool at 400.
that said, Goodfella's experience is representative of any properly built, fixtured and tuned 500 SAE hp FD. do it right, treat it right and the motor will last.
a couple of years ago i pulled my motor (507 SAE) which was running perfectly after 4 years... i wanted to take it apart and compare it to my build specs. mileage around 20,000. i don't drive it in wisconsin during the winter. the only spec that had changed was the sideseal gap had opened one thou. the motor gained compression with age and had the highest compression recorded when i disassembled it.
i disassemble lots of customer motors... they come in w huge amounts of internal carbon. here is a pic of my rotor after 4 years. this is exactly how it emerged w no cleaning whatsoever.
carbon is a motor killer.
to really appreciate an internally carbon free motor you just have to look at a typical FD disassembled motor. there is often up to almost a tenth of an inch of carbon covering the rotor...
apex seals, corner seals, side seals really need clearance to a thou of an inch to work properly... add in carbon and things go downhill fast.
our motors are more highly tuned, even in stock form, than we think.
there are solutions to make them pretty reliable even at the 500 rwhp level. they are all on this board.
hc
you have effectively 159 cubic inches. highly tuned factory street cars... turbo'd/supercharged, like the $117,000 ZR1 make 1.68 FLYWHEEL hp per cubic inch.
a 400 rwhp FD is making 460 FW hp or 2.89 hp per cubic inch. and most consider a 400 FD a medium range app.
we are in the deep end of the pool at 400.
that said, Goodfella's experience is representative of any properly built, fixtured and tuned 500 SAE hp FD. do it right, treat it right and the motor will last.
a couple of years ago i pulled my motor (507 SAE) which was running perfectly after 4 years... i wanted to take it apart and compare it to my build specs. mileage around 20,000. i don't drive it in wisconsin during the winter. the only spec that had changed was the sideseal gap had opened one thou. the motor gained compression with age and had the highest compression recorded when i disassembled it.
i disassemble lots of customer motors... they come in w huge amounts of internal carbon. here is a pic of my rotor after 4 years. this is exactly how it emerged w no cleaning whatsoever.
carbon is a motor killer.
to really appreciate an internally carbon free motor you just have to look at a typical FD disassembled motor. there is often up to almost a tenth of an inch of carbon covering the rotor...
apex seals, corner seals, side seals really need clearance to a thou of an inch to work properly... add in carbon and things go downhill fast.
our motors are more highly tuned, even in stock form, than we think.
there are solutions to make them pretty reliable even at the 500 rwhp level. they are all on this board.
hc
10-05-10, 12:33 PM
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Great responses, thanks a ton all. I tried to avail myself to all I could learn when I bought my first FD, a '94 with a fresh motor, think the car had like 50k on it when I bought it around 1998.
I'm sure you all remember Sport Compact Car's long-term build on their FD3S. That's what got me started and into mine. I had some terrible issues with an oil leak and a not so good and also arrogant wrench at the Mazda dealer, I went back at least three and maybe four times before it was fixed. At the time, I was a service manager at a dealer for already 10+ years and this wrench at one point was trying to convince me that gravity functioned differently around my car.
You really cannot argue with people like that. But you also cannot argue with oil still leaking. Anyway, that's a different story.
But in the end, I did very little to that car, I pulled the turbos and had them rebuilt, put on a down-pipe and a muffler. Never re-tuned the stock engine puter and she ran great. Did a few long distance road trips and probably put on some 25k before I sold the car.
Couple follow-ups:
Do you guys re-tune on a regular?
Sorry if this seems dumb, but if your AFRs is pretty dead on, or safely rich, and no additional mods have been done, why would a re-tune be needed?
This is for sure a noobie questions, but can someone point me to a good thread to learn more about Wideband O2s?
And, what, do you guys keep a constant eye on the AFR via the wideband? And, what, back off if it looks like it's running lean? And if it's running lean all the time get the car retuned?
I guess, as some have mentioned that you could get a wildcard: water in the fuel, shitty gas, weak fuel pressure or some other X-factor to have you run lean, detonate, and be done. But to me, by the time you're aware of a potential problem, the problem is already there? But who knows right, maybe for some of you, that backing off at the right moment could have stopped the motor from detonation??
I'm sure you all remember Sport Compact Car's long-term build on their FD3S. That's what got me started and into mine. I had some terrible issues with an oil leak and a not so good and also arrogant wrench at the Mazda dealer, I went back at least three and maybe four times before it was fixed. At the time, I was a service manager at a dealer for already 10+ years and this wrench at one point was trying to convince me that gravity functioned differently around my car.
You really cannot argue with people like that. But you also cannot argue with oil still leaking. Anyway, that's a different story.
But in the end, I did very little to that car, I pulled the turbos and had them rebuilt, put on a down-pipe and a muffler. Never re-tuned the stock engine puter and she ran great. Did a few long distance road trips and probably put on some 25k before I sold the car.
Couple follow-ups:
Sorry if this seems dumb, but if your AFRs is pretty dead on, or safely rich, and no additional mods have been done, why would a re-tune be needed?
And, what, do you guys keep a constant eye on the AFR via the wideband? And, what, back off if it looks like it's running lean? And if it's running lean all the time get the car retuned?
I guess, as some have mentioned that you could get a wildcard: water in the fuel, shitty gas, weak fuel pressure or some other X-factor to have you run lean, detonate, and be done. But to me, by the time you're aware of a potential problem, the problem is already there? But who knows right, maybe for some of you, that backing off at the right moment could have stopped the motor from detonation??
10-05-10, 06:47 PM
#16
So so true Howard. I have a 91 vert that I've been premixing since I rebuilt it back in 05. The engine currently has over 40k on it. I haven't driven the car in over a year but it fired up back in MAY without any issues (and I granny drove the hell out of this thing). Based on my driving habits, it should be carbon infested but I don't think it will be.
Hell even my 5th and 6th port actuators aren't stuck after sitting up. Premix does so much more than people think when it comes to COMPLETE lubrication of the combustion chamber and lower intake runners. I'm going to pull it apart for inspection to check for carbon and the conditions of my used housings since I used RA seals. I'm gonna just add my pics to your thread as further proof that EVERY ROTARY powered car should be premixing!
10-05-10, 09:15 PM
#17
This is for sure a noobie questions, but can someone point me to a good thread to learn more about Wideband O2s?
And, what, do you guys keep a constant eye on the AFR via the wideband? And, what, back off if it looks like it's running lean? And if it's running lean all the time get the car retuned?
I guess, as some have mentioned that you could get a wildcard: water in the fuel, shitty gas, weak fuel pressure or some other X-factor to have you run lean, detonate, and be done. But to me, by the time you're aware of a potential problem, the problem is already there? But who knows right, maybe for some of you, that backing off at the right moment could have stopped the motor from detonation??
And, what, do you guys keep a constant eye on the AFR via the wideband? And, what, back off if it looks like it's running lean? And if it's running lean all the time get the car retuned?
I guess, as some have mentioned that you could get a wildcard: water in the fuel, shitty gas, weak fuel pressure or some other X-factor to have you run lean, detonate, and be done. But to me, by the time you're aware of a potential problem, the problem is already there? But who knows right, maybe for some of you, that backing off at the right moment could have stopped the motor from detonation??
I am very attentive to the AFR readings before and immediately after tuning to make sure it was what I thought it should be... BUT as the weather would change just a bit (temperature, humidity, etc.) I noticed that AFRs and running condition of the motor would change... so I updated my tune accordingly. After a few small corrections, haven't touched my tune in some time, motor runs great.
I don't think that watching the WBO2 every time you floor it is reasonable though... I do it once in a while, esp when it's real cold outside or if I'm beating on a hot motor on the track (when risk of running lean is high) I have enough confidence in my tune and setup to not worry about it all the time. Even if you did run lean I don't think you could get your foot out of it before damage was already done.
10-06-10, 12:43 AM
#18
I have my wideband on my FC mounted on the steering column, below the tach so I can easily keep an eye on it
http://www.youtube.com/watch?v=9DR5pPwGOkk
It's been helpful because a couple times I've caught the car leaning out because I was low on gas and the fuel was sloshing around. Like any heavily modified car, piston or rotary, you've got to keep an eye on things. The kind of stuff that blows up heavily modified turbo rotaries also blows up heavily modified turbo piston motors (loss of fuel pressure for whatever reason, variations in tuning due to weather changes, overheating due to coolant leaks, etc).
http://www.youtube.com/watch?v=9DR5pPwGOkk
It's been helpful because a couple times I've caught the car leaning out because I was low on gas and the fuel was sloshing around. Like any heavily modified car, piston or rotary, you've got to keep an eye on things. The kind of stuff that blows up heavily modified turbo rotaries also blows up heavily modified turbo piston motors (loss of fuel pressure for whatever reason, variations in tuning due to weather changes, overheating due to coolant leaks, etc).
10-06-10, 01:20 AM
#19
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Couple follow-ups:
Do you guys re-tune on a regular?
Sorry if this seems dumb, but if your AFRs is pretty dead on, or safely rich, and no additional mods have been done, why would a re-tune be needed?
This is for sure a noobie questions, but can someone point me to a good thread to learn more about Wideband O2s?
Do you guys re-tune on a regular?
Sorry if this seems dumb, but if your AFRs is pretty dead on, or safely rich, and no additional mods have been done, why would a re-tune be needed?
This is for sure a noobie questions, but can someone point me to a good thread to learn more about Wideband O2s?
You see a lot of popped engines in the fall as it gets colder.
Contact Chuck Westbrook about his tuning notes, there is also a great tuning guide located in the single turbo section (but very useful for twins as well).
10-06-10, 10:27 AM
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One of the things that you need to consider is ambient temperature.
You see a lot of popped engines in the fall as it gets colder.
Contact Chuck Westbrook about his tuning notes, there is also a great tuning guide located in the single turbo section (but very useful for twins as well).
You see a lot of popped engines in the fall as it gets colder.
Contact Chuck Westbrook about his tuning notes, there is also a great tuning guide located in the single turbo section (but very useful for twins as well).
I don't have intimate working knowledge of the PFC or the stock PCM, but is there not a MAP or BAP sensor? As well as an intake air charge temp sensor that would compensate for cooler air temps and lower air pressure (for those going x-country, or those living in say Denver)?
I'm sure there is at least a MAP sensor, but I'm guessing that still, the mixture is not rich enough when air temps drop? And I'm sure that a given tune and how the car ran "that day" has much to do with the ambient temp/air pressure/humidity.
For those that have tuned your cars, have you canceled due to high ambient temps/high humidity for fear of being too lean once things cooled off/dried out?
And again, thanks for all the useful/helpful responses, I do appreciate it!
Last edited by DrFelixFig; 10-06-10 at 10:34 AM.
10-06-10, 02:45 PM
#21
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there is a map sensor, it's located on the firewall behind the throttle body, the PFC allows you to add or subtract fuel based on intake temperature, so you can continue tuning on hot days, but I think it would be better to start with cooler temps. The IAT sensor is located on the bottom side of the UIM and is roughly directly above the fuel injectors.
you cannot make adjustments to the tune with the stock ecu, a standalone is required, there are mutliple options.
you cannot make adjustments to the tune with the stock ecu, a standalone is required, there are mutliple options.
10-06-10, 03:40 PM
#22
Wow, this is a great thread! 
I don't have much to contribute, other than the fact that I run around the street on my 500+RWHP tune all the time, and my motor currently has around 4-5k on it (rebuilt it toward the end of summer '09, 3 mm RA black superseals, brand new rotor housings, RX-8 e-shaft, studded motor, etc).
I run a dual nozzle water/meth kit with variable pressure pump (coolingmist) and boost juice, premix 6 oz to every tank of fuel, only run 93 octane + 108 octane booster (or 110 octane race gas), change my oil + filter every 1500 miles and check it every time I drive the car, and basically just overmaintain the hell out of the thing.
As was stated, you'll see a lot of blown motors around fall due to the colder air temperature/higher oxygen density.
If you got tuned in the summer time with the PFC, you're going to be running leaner in the fall...There's no question about it. How much leaner? Well, that depends on what kind of tuner you had tune your car. I'm now a huge believer in AI, and it is a MUST in any rotary over ~400RWHP, IMHO.
However, even if you are diligent with your maintenance, run premix, run AI, change your oil regularly, etc, etc, you can still run into problems as people were saying. You can get a bad tank of gas, your AI pump can fail, your fuel filter can get clogged, your fuel pump can start failing, etc, etc. And really the only thing you can do is keep an eagle eye on your AFRs, and make sure you change things like your fuel filter. To the gurus here, would it also be a good idea to run some fuel injector cleaner through every few thousand miles to keep your injectors operating correctly? I'd think that'd be a good idea as well.
Again, there's no magic formula...Just regular maintenance and keeping an eye on as many variables as you can! (Mainly AFRs)
I don't have much to contribute, other than the fact that I run around the street on my 500+RWHP tune all the time, and my motor currently has around 4-5k on it (rebuilt it toward the end of summer '09, 3 mm RA black superseals, brand new rotor housings, RX-8 e-shaft, studded motor, etc). I run a dual nozzle water/meth kit with variable pressure pump (coolingmist) and boost juice, premix 6 oz to every tank of fuel, only run 93 octane + 108 octane booster (or 110 octane race gas), change my oil + filter every 1500 miles and check it every time I drive the car, and basically just overmaintain the hell out of the thing.
As was stated, you'll see a lot of blown motors around fall due to the colder air temperature/higher oxygen density.
If you got tuned in the summer time with the PFC, you're going to be running leaner in the fall...There's no question about it. How much leaner? Well, that depends on what kind of tuner you had tune your car. I'm now a huge believer in AI, and it is a MUST in any rotary over ~400RWHP, IMHO. However, even if you are diligent with your maintenance, run premix, run AI, change your oil regularly, etc, etc, you can still run into problems as people were saying. You can get a bad tank of gas, your AI pump can fail, your fuel filter can get clogged, your fuel pump can start failing, etc, etc. And really the only thing you can do is keep an eagle eye on your AFRs, and make sure you change things like your fuel filter. To the gurus here, would it also be a good idea to run some fuel injector cleaner through every few thousand miles to keep your injectors operating correctly? I'd think that'd be a good idea as well.
Again, there's no magic formula...Just regular maintenance and keeping an eye on as many variables as you can! (Mainly AFRs)
10-06-10, 06:12 PM
#23
meh
I watch my tune like a hawk but I don't do **** for maintainence compared to some people around here. I don't run AI. I don't premix (retained OMP). I don't have a water cooled turbo and I don't go out of my way to cool the engine down. Hell I don't even have a blowoff valve. I change the oil and plugs regularly and I don't boost the engine until it's warmed up. That's about it.
I do watch the wideband every time I boost (because it is located right under the tach), and unlike a lot of people I have set my PFC to cut fuel in the event of an overboost. I don't even have external gauges besides the wideband.
I watch my tune like a hawk but I don't do **** for maintainence compared to some people around here. I don't run AI. I don't premix (retained OMP). I don't have a water cooled turbo and I don't go out of my way to cool the engine down. Hell I don't even have a blowoff valve. I change the oil and plugs regularly and I don't boost the engine until it's warmed up. That's about it.
I do watch the wideband every time I boost (because it is located right under the tach), and unlike a lot of people I have set my PFC to cut fuel in the event of an overboost. I don't even have external gauges besides the wideband.
10-06-10, 06:41 PM
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Yeah, that's what I'm thinking too. But certainly more information about AFR, or in this case, any information for those w/o and AFR is certainly better!
For sure, cold dense, low humidy=lots of ponies!
I don't have intimate working knowledge of the PFC or the stock PCM, but is there not a MAP or BAP sensor? As well as an intake air charge temp sensor that would compensate for cooler air temps and lower air pressure (for those going x-country, or those living in say Denver)?
I'm sure there is at least a MAP sensor, but I'm guessing that still, the mixture is not rich enough when air temps drop? And I'm sure that a given tune and how the car ran "that day" has much to do with the ambient temp/air pressure/humidity.
For those that have tuned your cars, have you canceled due to high ambient temps/high humidity for fear of being too lean once things cooled off/dried out?
And again, thanks for all the useful/helpful responses, I do appreciate it!
For sure, cold dense, low humidy=lots of ponies!
I don't have intimate working knowledge of the PFC or the stock PCM, but is there not a MAP or BAP sensor? As well as an intake air charge temp sensor that would compensate for cooler air temps and lower air pressure (for those going x-country, or those living in say Denver)?
I'm sure there is at least a MAP sensor, but I'm guessing that still, the mixture is not rich enough when air temps drop? And I'm sure that a given tune and how the car ran "that day" has much to do with the ambient temp/air pressure/humidity.
For those that have tuned your cars, have you canceled due to high ambient temps/high humidity for fear of being too lean once things cooled off/dried out?
And again, thanks for all the useful/helpful responses, I do appreciate it!