What is the limit for the stock map sensor in my s5 turbo II. In the process of doing a street port build and more boost. But not sure how much I can run with the stock sensor

 

Theyre supposed to be 2 bar, one of vacuum and one of boost. Dont expect it to read any higher than 15psi.

 

this question really bothers me. are YOU building the motor/planning the ecu /upgrades. or is there someone in charge??? there needs to be. he needs to know what he is dong.

more boost? from stock turbo? best aim for no more then 12, even then you won't be able to control it and hit 15+ and blow your engine.
not stock turbo? then stock ecu?/.. again blown motor... not stock ecu? then.. not stock MAP!

need to understand soo many varibles to keep your engine alive...
just telling you that the map sensor is not the limiting factor in how much boost you can run isn't even the tip of the iceberg of the know-how and knowledge it will take to make a 300hp turbo rotary.. that last for more then 10k miles. is 300 still the goal??


Originally Posted by RotaryEvolution

 

the MAP sensor might read to 15psi, but the AFM, which is what controls fuel (in the stock system) is 100% open around... please hold, lemme look

 

and we're back. https://www.rx7club.com/2nd-generati...mo-afm-961741/ we'll be nice and assume the S5 AFM can measure as much as the Cosmo one, 440cfm. we know it takes about 1.9 cfm per hp, so that is about 230hp. keep in mind this is where the sensor stops reading, so it will flow more air, but the ecu won't do anything about it

 

The only hope is he has a stage2 rtek and can adjust fueling and spark as speed density, in which case 300 could be done but still not ideal on that primitive 8bit ecu.

 

Assuming the stock turbo, it's blowing mostly heat above 12 PSI, so about 12 PSI is as much as you can reasonably run. Of course the ECU cuts fuel at about 8 PSI to protect from an overboost situation. If you just defeat that with an FCD, the next mod will be rebuilding the blown engine.

Assuming an upgraded turbo, the stock MAP sensor doesn't matter as you'll be running an upgraded standalone ECU anyway.

 

I read through that whole thread and tell me if I am wrong...


You could run an N370 AFM on an S5 non-turbo and the car would be fine right?

 

maybe, probably not. these AFM's work on a 5-0v scale; with 0v being 100% open, and where your NA AFM might hit 0.5v at peak, the T2 will be less open, say 1v. the ecu not knowing the difference will see less load and run less injector duty and more timing.

or i think it would run lean

 

ran s4 t2 and s5 t2 on rtek 1.7 and 1.8. Pan speed hybrid and pushed up to 13-14 psi. Stock turbo will max at 12. Hybrids can handle more but map sensor max out at 15psi. Past that and Ecu has no idea what's going on.

So past 15 psi, standalone is required as there is no replacement to run a different map sensor. Can search if you like but I have before. lmk if something changes