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The 1/4 says that it is engineered for "high hp applications" which a normally aspirated rotary is not so not sure if it's worth it of if there will be any issues.
2- How many inches from the exhaust ports should the EGT sensors be placed?
I have fried several of the 3/16 and not many 1/4. The exposed tip 1/4” gets my vote…
depending on what other electronic package you have, you could potentially hook up the egt into your boost controller with an EGT amplifier. I think you are still on pfc right?
when i was running the pfc i had the plex boost control (PBC-pro) that had the 2 dedicated EGT channels . Some level of protection i suppose 😅
ideally you want to be as close to the combustion chamber as possible. I have run egt sensors pre turbo and post turbo (at the same time) and the difference in temperature is negligible.
if you are using only one egt (i like to use 1 per rotor) i would drill and mount it on the turbine housing inlet at the entrance if you are single turbo, or on the downpipe if you are on twins
i have run two EGTs since 2003. they have been a maintenance item. as they say on TV, "not anymore."
i have been running them since Dec 2021. i did a run today and the end of the run the sensors showed my front was 1787 and the rear was 1794. i buy my air thermocouples from The Sensor Connection but like the bombproof Super Series for my exhaust. EGT Technologies/Rick Lawler. i don't know how "fast" they are but all thermocouples are fast. i don't think it makes a difference whether they are 4 or 2 CPS. they tell you what you need to know tuning-wise. i run slightly diff ignition and fuel in my rotors.
when i took delivery of my GT3 RX3 from Roger Mandeville it had an analog (1983) EGT in the exhaust pipe. Roger instructed me to jet the Weber carb so as to show 1750 F at the end of the longest straight. this was a 12A making 259 flywheel hp... restricted w 38 mm rings. we generally didn't have to go more than one jet size...
Last edited by Howard Coleman; Aug 18, 2024 at 05:43 PM.
I have fried several of the 3/16 and not many 1/4. The exposed tip 1/4” gets my vote…
depending on what other electronic package you have, you could potentially hook up the egt into your boost controller with an EGT amplifier. I think you are still on pfc right?
when i was running the pfc i had the plex boost control (PBC-pro) that had the 2 dedicated EGT channels . Some level of protection i suppose 😅
ideally you want to be as close to the combustion chamber as possible. I have run egt sensors pre turbo and post turbo (at the same time) and the difference in temperature is negligible.
if you are using only one egt (i like to use 1 per rotor) i would drill and mount it on the turbine housing inlet at the entrance if you are single turbo, or on the downpipe if you are on twins
Thanks for the input @R-R-Rx7 . I'm surprised the 3/16 dies so quickly. What EGTs are you observing?
This will be for my RX8 race car running a Renesis so no turbo
i have run two EGTs since 2003. they have been a maintenance item. as they say on TV, "not anymore."
i have been running them since Dec 2021. i did a run today and the end of the run the sensors showed my front was 1787 and the rear was 1794. i buy my air thermocouples from The Sensor Connection but like the bombproof Super Series for my exhaust. EGT Technologies/Rick Lawler.
Thanks for the clarification on the EGT sensor vendors @Howard Coleman . I had read that old post you linked to (and others) but was trying to match the brand names you mentioned to the Sensor Connection website and totally striking out. I realize I was looking at the wrong site now.
Thanks for the input @R-R-Rx7 . I'm surprised the 3/16 dies so quickly. What EGTs are you observing?
This will be for my RX8 race car running a Renesis so no turbo
i completely missed the renesis application. I dont know what kind of temps are the renesis seeing but i highly doubt you will have anywhere near the REW temps.
When i was using the 3/16” sensor i was on my old setup and while my egts were pretty much dead even ,but they were very high. Ii would see often high north of 1000C and with peak reaching 1100C . I toasted a 3/16 sensor that i had installed a few days earlier on a “hill climb” session. High rpm lower speed. Everything was cooking in there
i completely missed the renesis application. I dont know what kind of temps are the renesis seeing but i highly doubt you will have anywhere near the REW temps.
When i was using the 3/16” sensor i was on my old setup and while my egts were pretty much dead even ,but they were very high. Ii would see often high north of 1000C and with peak reaching 1100C . I toasted a 3/16 sensor that i had installed a few days earlier on a “hill climb” session. High rpm lower speed. Everything was cooking in there
Wow! With the Renesis, I'm told to tune for about 13 AFR and somewhere around 1,500-1,550* F EGT iirc. Need to check my notes. The Renesis has a habit of cooking side seals because of the exhaust ports so I want nerd out a bit on the tune and see what I can do to ameliorate the situation. Especially for endurance racing.
Wow! With the Renesis, I'm told to tune for about 13 AFR and somewhere around 1,500-1,550* F EGT iirc. Need to check my notes. The Renesis has a habit of cooking side seals because of the exhaust ports so I want nerd out a bit on the tune and see what I can do to ameliorate the situation. Especially for endurance racing.
go a little richer for endurance racing! you'd hate to go home because it was too lean and detonated itself to death. or worse keep going...
this one time we put a 25 hour Honda together, and our tuner tried a bunch of different things, leaner being one of them. it didn't do anything for power, so he just left it.
but we were going to the 25, so it started knocking and blew the head gasket, so we had to stop and put water in it (the master switch also failed, so we had to stop and change the battery too, the master power switch is a wear part)
afterwards, we put a new engine in, went to the dyno and we tried the lean race tune and the stock tune, and the stock tune made more power.
we started leaning that out, and peak power was like 13.2:1 or something, but we left it richer, like 12.8, and we lost like 1-2hp.
go a little richer for endurance racing! you'd hate to go home because it was too lean and detonated itself to death. or worse keep going...
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Yes! Agreed!
I plan to add AFR and EGT and hit the dyno once the engine is rebuilt and the car is running to check the tune. The late Jim Mederer at RacingBeat apparently tuned the Renesis to around 13.2 according to old forum posts on rx8club. The current crew at RB doesn't have any tuning insights unfortunately. That seems a bit lean to me but we'll see what the dyno says. Eric Meyer and that document from Mazda for the Star Mazda Renesis also allude to not just tuning for AFR and power but consider the EGT (and oil, water temps etc).
It is also worth noting that the IRONS on the engine that I'm rebuilding were "worn" out around the combustion chamber. You could slip a 20 thou feeler between the housing and the irons. I'm going to assume that high combustion temps contributed to that with the current tune.
Here's another snippet from the starmazda program - which also alludes to 13.2 being a bit lean and was revised to .89 Lambda / 13.0 AFR.
I had a similar experience as you with a "tuner" who apparently decided to "tune" all race cars to 13.2 afr because he had talked to someone at a "nationals" race once upon a time who tuned to that afr... That day I discovered that some "tuners" don't get it. Not all cars are the same and not all cars should run the same AFR. Give the engine what it wants. I continued to richen up the fuel mixture on my Miata to 12.7 while on his dyno and it kept making more power. I want to try the same with the Renesis.
Last edited by gracer7-rx7; Aug 20, 2024 at 12:27 PM.
what they don’t like is to be over-revved past ~8,700 rpm. It’s a lot worse than running leaner and likely what caused that in addition to frying the side seal springs. Best to keep egt around 1600°F, 1650 max, which the higher revs will march it right past and higher still.
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what they don’t like is to be over-revved past ~8,700 rpm. It’s a lot worse than running leaner and likely what caused that in addition to frying the side seal springs. Best to keep egt around 1600°F, 1650 max, which the higher revs will march it right past and higher still.
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where does peak power generally happen? is it 8699rpm or is it lower?
thank you! i'm thinking about reviving my 1st gen as a NASA TT5 car, all my friends are running TT5.
Renesis is a consideration, although 270hp at the flywheel is MORE than the 12A Peripheral port (those were 265hp @9000 and 166lbs ft @8000rpm)
hadn’t been to the i-rotary site in a while and somebody pointed this out to me today, not really sure what to make of it since the dyno numbers are higher than any I’ve ever seen even with full depth RX7 Iannetti ceramic apex seals on an NA Renesis engine
In case anyone is curious - and so that I can find this information in the future, these are the sensors that EGT recommended I run for my track / racing use case https://www.exhaustgas.com/ProductDe...D=56&BasketID=
Which EGT sensor and where?
