Bogging down at point of turbo engagement. Why?

I suspect you can wire up a MPX4250AP to match the voltage scale, but it won't be pretty. Might be able to make it fit in the OEM case if it's not potted. Hmm. Are there a bunch of these turbo setups around?

 

It's carbureted. Pressurized carbs in fact, and it just regulates fuel flow like a normal carb but instead of being open to atmosphere, the float bowls are exposed to compressor boost pressure so there's still the same drop in the venturi.

 

12v DC power supply to + -, air regulator with large dial guage 0-30 psi, multimeter + to sensor output, - to DC power supply -

 

I re-conducted the test, pictures provided. 28psi gave me 4.9 V. I took apart the sensor... jeff said something about flexing a strain gauge for adjustment. I'll mess around with that.
psi v
0 2.2
6 2.9
12 3.6
4.9 28

 

Good luck with stressing the element. Looks to me like it's already exceeded stress limits and is failing outside of spec if you read 4.9V at 28psi. You can likely use that MAP module I posted earlier, with a couple of voltage dividing resistors (if needed). The scale looks pretty close to the OE spec. Or, you can grab one off eBay and hope it works.

 

Who ever flexes the element is a magician. I broke the sensor just taking it apart.

Anyone about replacements??

 

eBay has some used ones for around $30. Or you can look into the MPX4250AP. It has 3 active pins, +5VDC VCC, GDN, VOut. If I knew there was demand for it I'd work on a replacement kit.

 

I read the turbo manual it describes how the system works.
the one thing that caught my attention was why Yamaha located the turbo under the bike. 1500 degree exhaust.

 

It has to be wrapped in a blanket or be in a draft to reduce heat soak.

 

Cover it with a chicken.
Tandoori, yumm.

 

I have cooked many lunches on truck engines working DOT college summers. Not to go on a tangent.

 

Still trying to get signal specs on this. Standard MAP module for the Innovative wideband boost controller.

 

Just tested a replacement sensor I got from ebay. Sensor voltage output was 2.2 regardless of pressure. It was worse than the one I just took off!

 

a generic 1BAR map sensor can likely be used but it really depends on the linearity of the resistance. Can you check on the harness connector that you're getting 5VDC signal to one of the terminals? Or is it 12V?

 

I'm thinking something like a bosch 1bar map would probably work, but would need to verify voltage response to pressure range from the manual.

https://www.ebay.com/itm/GM-STYLE-M...332705?hash=item43fa3121a1:g:F9AAAOSwLXFcbRVI

 

Honestly, it looks like you've piped the 4 to 1 to the Exh side, the EXIT of the turbo............


Also, how are you supplying oil to the turbo & have you confirmed flow?


jeff

 

Look at this pic of a Ebay generic turbo......one either end of the turbo are the turbine and impeller...The Exh muffler goes on the dark side round end and the surge tank connects to the silver "spout". The rectangle flange goes to the exh(4-1). The air intake goes to the silver end of the turbo....do this with zero leaks, plenty of oil to the turbo and you should be good to go on the air side.

On the fuel side.....confirm a good fuel pump...no pressure=no boost....and it won't matter what else you do to the bike...no pressure=no boost.

Pressure of the fuel must exceed desired boost.

jeff

 

Here's some advice I've given for the Waste Gate:

I have often given the advice right or wrong, to sand and smooth the waste gate till it holds a glass of water......it takes a couple of hours but the thinking is...is that once you do that, you don't loose any boost through a :"leaker" and you never wonder, provided you set your gate to operate when you want it to. That joint and the exh joints are critical to higher boost numbers. The good news is most of us never have an issue with exh leaks.

Here's a pic of how I "plumbed" mine fwiw....(you might have to open it in secondary program if it doesn't look right). Remember...the valve is normally closed....what you are setting is the pressure in which it opens! It took me a minute to get my head around that ....but it's been good to go since. I piped the second tap on the valve to the boost gauge. I mounted mine underneath the gauge on the left side fairing. It's the only place I came up with that allowed me to set it while riding and still be out of sight. Once dialed in, I've never touched in in how many years?


good luck,

jeff

 

Yeah that looks to be backwards.