Thread: Max Voltage for MAP sensor
06-20-2014, 01:51 AM #1
Max Voltage for MAP sensor
does anyone know what the max voltage is for our MAP sensors? im still not able to get passed 83-8400 RPMs and at this point im pretty sure i just need to throw this voltage clamp on.
06-20-2014, 02:32 AM #2
- Join Date
- May 2013
Maybe this helps?
I asked Keith from Dynotune about the voltages from the MAP on both Bosch & Siemens ECUs, with relationship to Kpa, here's his answer.
They are not exactly the same, but very close. The slope is also very similar. 54.9kPa per volt for the 6212 and 55.4kPa per volt for the 6210. For all intents and purposes, it’s the same.
CMDM-6210 – 1.5V = 75kPa, 4.5V = 240kPa
CMDM-6212 – 0.4V = 20kPa, 4.65V = 250kPa
06-20-2014, 09:24 AM #3
The voltage is not that big of a deal. It what the ecu is tuned for thats is the problem.
If the map is setup for small injectors thats the problem. At a certain rpm and boost setting the ecu commands the injectors to run 100% open to try and keep up with demand.
Now you installed bigger injectors and a cmd but the ecu dosent know that so it still commands 100% dc while the cmd pulls say 20%.
Now the problem comes with the cmd it gets its tach (rpm) signal from the injector but when the injector stays open all the time the cmd has no idea what the rpm is and it dose some weird stuff.
To fix this you can do 2 things. Get a ecu that is setup for bigger injectors, or use a voltage clamp to fool the ecu into thinking you have lower boost so that it dose not command the injectors to 100%
If you use the clamp make sure you dont clamp the signal to the cmd.
06-20-2014, 09:57 AM #4
Yeah im runnin an old Riva 8650. I plan on clamping it for now until i change maps. Whats the max boost on the Riva? and what would that voltage be so i now what to clamp it at?
06-20-2014, 12:22 PM #5
I had the same problem with the same ecu.
What you need to do is install the clamp and have the clamp high then as you ride slowly lower the clamp voltage down until you no longer see 100% duty cycle from the ecu. Then go just a little more so you dont have problems later when the weather cools down.
I dont know the exact voltage its something your going to have to play with to get it right.
Dont clamp it to low as it effects other stuff like ign timing ect.....
06-20-2014, 12:49 PM #6
Clamping your MAP voltage isn't a fix, its a band-aid... and a bad idea IMO.
06-20-2014, 12:50 PM #7
what was the max boost that ECU was meant to be at with the old Riva charger? like 13-14lbs i think. cuz the most i can get before anything starts to get funky is 14lbs of boost around83-8400. Ill find the voltage equivalent to 13lbs and start there see what happens.
06-20-2014, 12:50 PM #8
06-20-2014, 12:52 PM #9
06-20-2014, 12:53 PM #10
I ran the ski fine for 40 hours as is last summer before i sheered the fly wheel bolts. she rips and runs amazing just acts like 8300-8400 is the limiter.
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