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-   -   Exhaust Gas Temp readings? (https://www.rx8club.com/series-i-engine-tuning-forum-63/exhaust-gas-temp-readings-183303/)

newguy 09-27-2009 08:10 AM

Exhaust Gas Temp readings?
 
Im a rotary noob. I know they run hotter but how hot is safe? I searched but saw nothing. I know the FD had no knock sensor, the 8 doesnt either correct? So I assume the only way to tune is AFR, and exhaust gas temp.

1) What is a safe EGT for tuning a N/A car?
2) What are safe EGTs for tuning a car with the Greddy turbo kit installed?
3) Does the Cobb/MM AP datalog AF ratios?

Ive modded 2 4G63 (EVO) motors in the past and just leaned them out until 1-2 knocks per redline pull was registered so timing advance isnt pulled while keeping EGTs under 1650*F. This was using an Apexi SAFC to trick the ECU airflow readings while using bigger injectors, keeping them under a 90% duty cycle as boost varied on race/pump gas for the strip/street. The 8 looks like its a bit more $ to coax the hp from but well worth it after owning it for a while now.

The Mitsu Eclipse/Eagle Talons have datalogger software available as free shareware used in conjunction with an old Palm M100 and diagnostic port cable you can get for $20, but I will bite the bullet and go Cobb/MM for ease of use.

TIA

arghx7 09-29-2009 04:32 PM

2 Attachment(s)
I don't think many people are running aftermarket, pre turbo EGT. On my Rx-7 I usually see 1650-1700 preturbo on the rear rotor and 1500-1550 preturbo on the front. The rear rotor always runs at least somewhat hotter on a rotary. This is in part due to the fact that the coolant always hits the front rotor first.

The FD had a knock sensor in the front rotor housing, you just can't always trust it. The FC had a knock sensor in the middle side housing, between the front and rear rotor. The Cosmo 20B had dual knock sensors. And Rx-8's also have knock sensors.

https://www.rx8club.com/attachment.p...1&d=1254259867

The 2009's have one for each rotor.

https://www.rx8club.com/attachment.p...1&d=1254259867


This was using an Apexi SAFC to trick the ECU airflow readings while using bigger injectors, keeping them under a 90% duty cycle as boost varied on race/pump gas for the strip/street.
DSM style tuning is really asking for it on these cars. You've got to pay a lot more attention to fuel trims etc. My advice to you is to study as many rotary/Rx-8 timing maps as you can, and keep the AFR in the 11's somewhere.

arghx7 09-29-2009 04:37 PM

also, PM me. I have two documents that go into exacting detail about how the Rx-8 PCM works, including the control tables themselves as well as the block diagrams of how the major systems work.

Razz1 09-29-2009 04:40 PM

They all have knock sensors for the RX8

newguy 09-29-2009 11:06 PM

Thank you and PMed, please forgive any ignorance on my part, the rotary is obviously a different beast to tame and Id like to get it right on the first try once I decide on a sc or turbo. Im searching but new territory takes time to map.

Im reading the Greddy turbo has a low life span lacking a water cooled center cartridge but there is a $1k upgrade to address this, but 1K plus $3.5k buy in price for the Greddy kit puts you close to SC money. I read the included Greddy Emanage unit isnt the best tuning tool as well so add another $700 for a MM AP and youre at $5k.

Question- Does the Pettit SC come with a reliable tuning tool for the kits price or is the MM AP recommended for that kit as well?

Also common sense tells me a hotter running rotary would rather have an intercooled SC with no exhaust restrictions (Ive ordered a catless midpipe already) than a heat soaked turbo hanging off of a blazing hot exhaust manifold with the added backpressure and heat on the exhaust ports. I see the Pettit has a built in liquid intercooler whereas the Greddy kit requires plumbing and hanging an air to air intercooler in front of an already stressed radiator. Am I correct in this assumption?

I want to do my own wrenching and working all on top w/ the Pettit seems alot easier than getting the exhaust mani off and hanging the intercooler out front. Does the motor need to be jacked up to remove the ex mani?

I see stock injectors works for 8psi, is the stock fuel pump up to the task? no mention was made w/either kit.

many questions, I know, sorry.

I want to jump but I have 39K left on my warranty so I am timid at this point at least until I learn more.


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