Pre Turbo WI vs Post IC WI Dyno Test Results!
04-18-12, 09:41 AM
#51
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thanks for the pictures Chuck, that looks good, I should get an air filter like that one and then I could put the injector there also and that would probably be better than spraying into the side of my intake pipe. my air filter sits down low behind the front bumper. What air filter is that? they sell cheap ones like that at advance auto parts but I didn't want to try one.
http://www.sbfilters.com/Store/Round-w-Flange
04-18-12, 12:41 PM
#52
interesting results but i'm not seeing a great discrepency aside from the compressor remapping other people suggested by relocating the nozzle creating a larger wheel map.
keep in mind higher peak numbers do not create a quicker car, large flat numbers that drag on as long as possible do. i would prefer to have a turbo hit at 3500rpms creating say 350whp than a turbo that hit at 4500rpms that peaked at 400whp for a shorter duration, the first example would build boost faster between shifts also.
i have driven plenty of dyno queens and they did not feel quick to me even though their peak numbers were impressive.
the best bet would be to find your crossover point where the turbo lag down low hurt the turbo response and have the AI kick on just before the point where the 2 maps crossed for the preturbo injection. tuning your results could net you some positive gains all around.
interesting nonetheless, as i haven't had a chance to personally test changing the locations but i figured the results would be similar to this but i am curious the results compared between 50/50 meth/water after turbo compared to pure water preturbo. IMO that would give more similar results between the 2 setups but without the drastic heat soaking issue you noticed. but keep in mind the pre-throttle body AI is going to skew the figures as the IAT is getting soaked with water directly, pre turbo the water has already been broken down and is not soaking the IAT with water, i do believe there is more heatsoak from preturbo but not as large as you noted due to skewed readings.
keep in mind higher peak numbers do not create a quicker car, large flat numbers that drag on as long as possible do. i would prefer to have a turbo hit at 3500rpms creating say 350whp than a turbo that hit at 4500rpms that peaked at 400whp for a shorter duration, the first example would build boost faster between shifts also.
i have driven plenty of dyno queens and they did not feel quick to me even though their peak numbers were impressive.
the best bet would be to find your crossover point where the turbo lag down low hurt the turbo response and have the AI kick on just before the point where the 2 maps crossed for the preturbo injection. tuning your results could net you some positive gains all around.
interesting nonetheless, as i haven't had a chance to personally test changing the locations but i figured the results would be similar to this but i am curious the results compared between 50/50 meth/water after turbo compared to pure water preturbo. IMO that would give more similar results between the 2 setups but without the drastic heat soaking issue you noticed. but keep in mind the pre-throttle body AI is going to skew the figures as the IAT is getting soaked with water directly, pre turbo the water has already been broken down and is not soaking the IAT with water, i do believe there is more heatsoak from preturbo but not as large as you noted due to skewed readings.
Last edited by RotaryEvolution; 04-18-12 at 12:51 PM.
04-18-12, 10:39 PM
#53
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Since nobody stated the reason for Tom's turbo slower spoolup, or a better possible solution, I will. So in simplistic words.
A pump consumes/needs more power to pump a denser fluid at a fixed rate than required for a less dense fluid.
The upside is the denser fluid also cooled more and became even more den se to produce more power.
Better to split the WI to pre-turbo and post IC for best all around benefit.
A pump consumes/needs more power to pump a denser fluid at a fixed rate than required for a less dense fluid.
The upside is the denser fluid also cooled more and became even more den se to produce more power.
Better to split the WI to pre-turbo and post IC for best all around benefit.
05-15-12, 10:55 PM
#56
I tore apart my engine today (page 2 has some info about the blown engine), this is my first rotary engine disassembly so I'm sure I have alot to learn and may be missing something.
2 corner seals from the rear rotor were broken in half, and the rubber corner seal plugs were damaged. The front rotor had damaged/broken rubber corner seal plugs, the metal corner seals were not broken. A couple of the corner seal springs were flattened a bit. I'll have to use solid corner seals when I rebuild it like these http://atkinsrotary.com/store/produc...51&cat=&page=1 since I guess the stock rubber corner seal plugs were probably not a good idea to use with high boost?
The rear rotor housing is significantly scratched up, and the ALS seals have some small nicks in them, I guess this is from the broken rubber corner seals? The front rotor housing has a smaller amount of scratches, apex seals are smoother. Many of the apex seals do look a little warped on the 45 degree ends.
Both rotors have 1 noticeable decent size dent, hard to see in a picture though, and both have one very small barely noticeable dent.
I'm not sure about the irons, they feel a little uneven half way up on the drivers side where the corner seals would run across them, I don't know if they are smooth enough or should be replaced, but it looks like the rotors and rotor housings need replaced for sure.
So I'm wondering if detonation caused the problems or if that failed water injector check valve and all that extra large amount of water going through the engine could have caused the dents in the rotors, right after I had the water injection problem is when the engine wasn't making as much power or compression.
The AFR was a little leaner than normal before this happened at the track, a vacuum cap popped off the upper intake manifold at the beginning of the run which caused the afr to be a little leaner than normal (low 12s AFR), this happened once or twice last year and the engine was fine and it was a good run, I didn't know why the afr was too lean then found the vacuum hose that popped off and then the next run the afr was richer/back to normal.
And right before it happened after switching into 4th gear, there was a drop in fuel pressure logged from 67psi to 52psi, but it was for only 1 datapoint (11 samples/second) so I don't know if it really dropped fuel pressure or not, there was no afr lean spike and no other drop of fuel pressure throughout the run.
Let me know what you guys think, thanks!
2 corner seals from the rear rotor were broken in half, and the rubber corner seal plugs were damaged. The front rotor had damaged/broken rubber corner seal plugs, the metal corner seals were not broken. A couple of the corner seal springs were flattened a bit. I'll have to use solid corner seals when I rebuild it like these http://atkinsrotary.com/store/produc...51&cat=&page=1 since I guess the stock rubber corner seal plugs were probably not a good idea to use with high boost?
The rear rotor housing is significantly scratched up, and the ALS seals have some small nicks in them, I guess this is from the broken rubber corner seals? The front rotor housing has a smaller amount of scratches, apex seals are smoother. Many of the apex seals do look a little warped on the 45 degree ends.
Both rotors have 1 noticeable decent size dent, hard to see in a picture though, and both have one very small barely noticeable dent.
I'm not sure about the irons, they feel a little uneven half way up on the drivers side where the corner seals would run across them, I don't know if they are smooth enough or should be replaced, but it looks like the rotors and rotor housings need replaced for sure.
So I'm wondering if detonation caused the problems or if that failed water injector check valve and all that extra large amount of water going through the engine could have caused the dents in the rotors, right after I had the water injection problem is when the engine wasn't making as much power or compression.
The AFR was a little leaner than normal before this happened at the track, a vacuum cap popped off the upper intake manifold at the beginning of the run which caused the afr to be a little leaner than normal (low 12s AFR), this happened once or twice last year and the engine was fine and it was a good run, I didn't know why the afr was too lean then found the vacuum hose that popped off and then the next run the afr was richer/back to normal.
And right before it happened after switching into 4th gear, there was a drop in fuel pressure logged from 67psi to 52psi, but it was for only 1 datapoint (11 samples/second) so I don't know if it really dropped fuel pressure or not, there was no afr lean spike and no other drop of fuel pressure throughout the run.
Let me know what you guys think, thanks!
05-16-12, 06:08 AM
#57
I have no input on the engine as I too am a noob in that area.
On the fuel logging, 15psi is very significant. You are running a single Stealth correct? But like you said, the AFR's weren't logged as lean so that is very suspect. Unless, the FP sensor can react within a data point timeframe and the wideband can't, I would say its a glitch. I would be interested to see the reaction timing in milliseconds from each device. May want to double check your pump wiring and all that jaz, just in case.
On the fuel logging, 15psi is very significant. You are running a single Stealth correct? But like you said, the AFR's weren't logged as lean so that is very suspect. Unless, the FP sensor can react within a data point timeframe and the wideband can't, I would say its a glitch. I would be interested to see the reaction timing in milliseconds from each device. May want to double check your pump wiring and all that jaz, just in case.
05-16-12, 08:07 AM
#58
Racing Rotary Since 1983
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Tom,
i do not know what caused your motor problem but i do know what happened internally.
broken corner seals = knock.
flattened corner seal springs = too much heat from knock.
check your apex seal springs for proper arc as they may be also effected.
dished rotors = too much heat.
it is unlikely the rubber corner seal plugs caused any damage. i recommend Atkins Competition corner seals for your app.
the missing vacuum cap would have had little effect under boost as you are ramming massive amounts (around 1000 CFM) of air into the motor and relatively little would be escaping... the miniscule amount that did escape would have simply lowered your boost and your base fuel map would have trimmed accordingly.
it is most probable you were lean.
logging at 11/second is catching about 10% of the data at high RPM.
howard
i do not know what caused your motor problem but i do know what happened internally.
broken corner seals = knock.
flattened corner seal springs = too much heat from knock.
check your apex seal springs for proper arc as they may be also effected.
dished rotors = too much heat.
it is unlikely the rubber corner seal plugs caused any damage. i recommend Atkins Competition corner seals for your app.
the missing vacuum cap would have had little effect under boost as you are ramming massive amounts (around 1000 CFM) of air into the motor and relatively little would be escaping... the miniscule amount that did escape would have simply lowered your boost and your base fuel map would have trimmed accordingly.
it is most probable you were lean.
logging at 11/second is catching about 10% of the data at high RPM.
howard
Last edited by Howard Coleman; 05-16-12 at 08:11 AM.
05-16-12, 08:36 AM
#59
Thanks for the info guys. Howard, one day last year my first two runs the AFR was too lean and I didn't understand why cause my tune was good on the way out to the track, until I found the pressure hose that goes to the primary injectors had popped off, causing a boost leak, but the boost pressure was not effected, I fixed the hose and the next run the afr was richer back to normal, same boost pressure. My theory is that the turbo had to work harder to achieve the desired boost pressure from the boost controller and therefore had to make more cfm of air so actually more cfm of air was getting to the engine and causing it to run lean even at the same boost pressure, does that sound possible? That's the only way I could explain it.
05-16-12, 09:55 AM
#61
I put in a walbro 400 a few months ago, haven't had any problems with it and I don't think I've seen any other drops in fuel pressure in all my datalogs, so its a little weird. Datalogit only logs 11 samples per second when datalogging aux, advanced, basic and map ref which is needed to log inj. duty cycle. Maybe it just wasn't lean enough long enough to show up in the afr if there really was a super quick drop in fuel pressure.
05-16-12, 10:38 PM
#66
I havent gone back and looked and seen if it is in this thread or another that I predicted it was broken corner seals and not apex seals that caused your blown engine symptoms. This is the 3rd case where i have seen corner seals let go before the ALS seals ever let go. These seals truly are amazing.
Everyone reading this, keep in mind that Tom was running 24psi on pump gas with water injection, and running low 10 sec 1/4 mile passes on 93 octane. That is asking a lot of this little engine, and I cant think of too many others who have ran these times on 93 octane, truly impressive.
The dents in the rotor are from detonation, plain and simple. Same as with the side seals, it is impressive that the apex seals held up and you likely dont have damage to the turbine of the turbo but you should check to be sure. In extreme cases the rotors will dent so badly it will actually pinch the apex seal and lock it in place leading to low compression. I havent seen extreme wear with the ALS seals upon the very few disassemblies I have done with these seals. However, with water injection, housing wear is accelerated with any apex seal without proper lubrication.
Post pics of the housings, as I am interested myself to see the wear. Goopy offers a nice resurfacing service as long as there are no extreme gouges in the housing or bad cracking by the plugs it is a great deal for the cost.
Once again, congrats on the great results you achieved on pump gas. Great to see people push the envelope, especially the DIY guys doing their own tuning and experimenting.
Everyone reading this, keep in mind that Tom was running 24psi on pump gas with water injection, and running low 10 sec 1/4 mile passes on 93 octane. That is asking a lot of this little engine, and I cant think of too many others who have ran these times on 93 octane, truly impressive.
The dents in the rotor are from detonation, plain and simple. Same as with the side seals, it is impressive that the apex seals held up and you likely dont have damage to the turbine of the turbo but you should check to be sure. In extreme cases the rotors will dent so badly it will actually pinch the apex seal and lock it in place leading to low compression. I havent seen extreme wear with the ALS seals upon the very few disassemblies I have done with these seals. However, with water injection, housing wear is accelerated with any apex seal without proper lubrication.
Post pics of the housings, as I am interested myself to see the wear. Goopy offers a nice resurfacing service as long as there are no extreme gouges in the housing or bad cracking by the plugs it is a great deal for the cost.
Once again, congrats on the great results you achieved on pump gas. Great to see people push the envelope, especially the DIY guys doing their own tuning and experimenting.
05-16-12, 10:57 PM
#67
Thanks. Pics here - http://czfitnessproducts.com/tom94RX-7/Blown-engine/
Definitely seems like the ALS seals held up great. The turbine wheel looks good, no damage. And there were not any stuck seals.
Not sure what my plans will be after I rebuild it, but I will likely run more water, more premix oil, and don't push the envelope as much with the AFR like I was doing haha.
Thanks.
Definitely seems like the ALS seals held up great. The turbine wheel looks good, no damage. And there were not any stuck seals.
Not sure what my plans will be after I rebuild it, but I will likely run more water, more premix oil, and don't push the envelope as much with the AFR like I was doing haha.
Thanks.
05-17-12, 07:24 AM
#69
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Do you think that knock control box would have help in your case? Howard mentioned corner fault due to knock. Seems like you have great setup there and wondering if knock detect/retard would make it complete?
05-17-12, 07:47 AM
#70
This all sounds very familiar 
See my experience below - also running WI and 93. At that point I wasn't running full water flow. I am now with no problems, and more hp (and an extra fuel pump)
https://www.rx7club.com/showpost.php...2&postcount=49
See my experience below - also running WI and 93. At that point I wasn't running full water flow. I am now with no problems, and more hp (and an extra fuel pump)https://www.rx7club.com/showpost.php...2&postcount=49
05-17-12, 07:58 AM
#71
Racing Rotary Since 1983
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the engine damage looks exactly like it should given an overly lean condition. i took a motor apart two weeks ago that was a carbon copy. it had partially flattened apex seal springs so i suggest you take a careful look.
as to knock...
i think it is important to accurately measure/log knock. knock, properly observed, is a leading indicator for tuning/setup. knock w proper tuning is fairly linear so you can be ahead of it.
OTOH, according to my go-to guy (Jose Le Duc) active knock response systems will not normally save a rotary. by the time you really have an event the chances are the damage is done. i have yet to find Jose wrong on anything material since 2004. given he is making more than 1000 rwhp from his 13 Brew i appreciate his knowledge.
my new ECU does have a very sophisticated active knock response system and of course i will enable it so we will see. i am using (two) RX8 knock sensors that are a later generation Bosch design compared to the FD sensor. BTW, i think the FD sensor works quite well w the Power FC.
Tom, as to looking forward w your FD. as you know RiceRacing has run/pioneered for the FD, pre turbo AI for a number of years. successfully. for a number of years he was running around 20 psi. about a year+ ago he added about 50% meth to the water. this has allowed him to run 30-34 PSI! after a year of running 30 PSI his motor is showing excellent compression.
sonds like a plan to me.
congrats on what you have accomplished to date and good luck,
howard
as to knock...
i think it is important to accurately measure/log knock. knock, properly observed, is a leading indicator for tuning/setup. knock w proper tuning is fairly linear so you can be ahead of it.
OTOH, according to my go-to guy (Jose Le Duc) active knock response systems will not normally save a rotary. by the time you really have an event the chances are the damage is done. i have yet to find Jose wrong on anything material since 2004. given he is making more than 1000 rwhp from his 13 Brew i appreciate his knowledge.
my new ECU does have a very sophisticated active knock response system and of course i will enable it so we will see. i am using (two) RX8 knock sensors that are a later generation Bosch design compared to the FD sensor. BTW, i think the FD sensor works quite well w the Power FC.
Tom, as to looking forward w your FD. as you know RiceRacing has run/pioneered for the FD, pre turbo AI for a number of years. successfully. for a number of years he was running around 20 psi. about a year+ ago he added about 50% meth to the water. this has allowed him to run 30-34 PSI! after a year of running 30 PSI his motor is showing excellent compression.
sonds like a plan to me.
congrats on what you have accomplished to date and good luck,
howard
Last edited by Howard Coleman; 05-17-12 at 08:00 AM.
05-17-12, 08:51 AM
#73
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the engine damage looks exactly like it should given an overly lean condition. i took a motor apart two weeks ago that was a carbon copy. it had partially flattened apex seal springs so i suggest you take a careful look.
as to knock...
i think it is important to accurately measure/log knock. knock, properly observed, is a leading indicator for tuning/setup. knock w proper tuning is fairly linear so you can be ahead of it.
OTOH, according to my go-to guy (Jose Le Duc) active knock response systems will not normally save a rotary. by the time you really have an event the chances are the damage is done. i have yet to find Jose wrong on anything material since 2004. given he is making more than 1000 rwhp from his 13 Brew i appreciate his knowledge.
my new ECU does have a very sophisticated active knock response system and of course i will enable it so we will see. i am using (two) RX8 knock sensors that are a later generation Bosch design compared to the FD sensor. BTW, i think the FD sensor works quite well w the Power FC.
Tom, as to looking forward w your FD. as you know RiceRacing has run/pioneered for the FD, pre turbo AI for a number of years. successfully. for a number of years he was running around 20 psi. about a year+ ago he added about 50% meth to the water. this has allowed him to run 30-34 PSI! after a year of running 30 PSI his motor is showing excellent compression.
sonds like a plan to me.
congrats on what you have accomplished to date and good luck,
howard
as to knock...
i think it is important to accurately measure/log knock. knock, properly observed, is a leading indicator for tuning/setup. knock w proper tuning is fairly linear so you can be ahead of it.
OTOH, according to my go-to guy (Jose Le Duc) active knock response systems will not normally save a rotary. by the time you really have an event the chances are the damage is done. i have yet to find Jose wrong on anything material since 2004. given he is making more than 1000 rwhp from his 13 Brew i appreciate his knowledge.
my new ECU does have a very sophisticated active knock response system and of course i will enable it so we will see. i am using (two) RX8 knock sensors that are a later generation Bosch design compared to the FD sensor. BTW, i think the FD sensor works quite well w the Power FC.
Tom, as to looking forward w your FD. as you know RiceRacing has run/pioneered for the FD, pre turbo AI for a number of years. successfully. for a number of years he was running around 20 psi. about a year+ ago he added about 50% meth to the water. this has allowed him to run 30-34 PSI! after a year of running 30 PSI his motor is showing excellent compression.
sonds like a plan to me.
congrats on what you have accomplished to date and good luck,
howard
05-17-12, 09:58 AM
#74
During the highway pull on the way to the track the knock spiked to 90 at 5300 rpm then the engine sputtered/lost power and I let off the gas, the datalog showed high knock for about one whole second, the afr was at about 11.5 and no drop in full pressure. The only obvious cause I think would be cause I was spraying less water.
At the track when it started knocking in 4th gear I didn't let off the gas, it knocked and sputtered for about 1.5 seconds until I let off the gas at the finish line, since I didn't let off that's probably when the corner seals broke, the boost stayed up around 24 psi and afr was around 11-11.5 throughout.
At the track when it started knocking in 4th gear I didn't let off the gas, it knocked and sputtered for about 1.5 seconds until I let off the gas at the finish line, since I didn't let off that's probably when the corner seals broke, the boost stayed up around 24 psi and afr was around 11-11.5 throughout.
05-17-12, 11:41 AM
#75
Racing Rotary Since 1983
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"Doesn't knock increase progressively with RPM"
knock sensors do pick up noise as well as knock. rotary knock, i believe, is around 4200 Hz. as you log knock you may find in vacuum you have readings around 40/50 and this is generally noise.
as you get into boost knock should drop w RPM and boost and if properly tuned knock should be under 25. (i assume you are using some proper form of AI)
anything not generally resembling this profile should be of concern.
i consider knock logging essential for tuning and living w a rotary. when knock readings don't fit the proper profile the caution light should come on and you should start looking for answers before bad things happen.
the rotary knock system functions as a caution light and in so doing does save motors.
90 at 5300 under load (pedal to metal) would be a caution light turning red.
howard
knock sensors do pick up noise as well as knock. rotary knock, i believe, is around 4200 Hz. as you log knock you may find in vacuum you have readings around 40/50 and this is generally noise.
as you get into boost knock should drop w RPM and boost and if properly tuned knock should be under 25. (i assume you are using some proper form of AI)
anything not generally resembling this profile should be of concern.
i consider knock logging essential for tuning and living w a rotary. when knock readings don't fit the proper profile the caution light should come on and you should start looking for answers before bad things happen.
the rotary knock system functions as a caution light and in so doing does save motors.
90 at 5300 under load (pedal to metal) would be a caution light turning red.
howard