I have my m90 plumbed and running, but at 2800 rpm the engine stalls and then continues but with no power. It also will boost fine till that point. I also noticed that my max rpm is 6500 rpm, but it takes some doing to get there.

Any help would be gladly accepted.

 

Secondary injectors not working? Sounds like something electrical gremlins wise.

 

I thought about that also but I thought they kicked in at 3500-3800 rpms.

 

What is your air fuel ratio at the point when the engine stalls? What kind of fuel control are you using? What size injectors and/or what rise ratio fmu?

 

I only have an Autometer guage but it is in the green the whole time. I am using AFCII with +10 at 3000 rpm. Also I might mention, the engine does this even if you are sitting still and not pushing the pedal very hard (slow increase in rpm)

 

Also I have messed with the increase and decrease up and down and it makes no change in how it is acting.

 

Well...i had to say it, but the obvious solution is to take the SC off and see if you have the same problems. Maybe you have it belted wrong and the SC is hitting the wall.

 

I agree, I will remove the supercharger and see what happens, I will let you know after I do it.

 

Do rotaries have knock sensors or some type of knock device? If you're overspinning that M90 it'll superheat the air, that may cause you to ping, and the computer to pull power? I was thinking the Mazda computer wasn't smart enough to do that, but perhaps I'm wrong?

 

Finally figured out the problem, my lower intake hose was colapsing. I changed it out with a radiator elbow hose and problem is gone. Now I just need to find the boost leak. I am maxing out at 4 psi boost @ 3000 rpm. After that it just stays at 4 psi all the way to 7000 rpm.

 

Very nice, you need to take pictures and post them! I want to see what it looks like!

Also, Tii and Verts have knock sensors that the ECU reads. I don't know if it pulls power or not, but i do know it's there.

 

Im thinking its more of your pully size thats the issue-

 

yes which pulley are you using? If you are using the power steering pulley then it should put out about 7 lbs I think?

 

I am using the stock pulley that came on the supercharger - I think it is 3.125".

Also I just got back from towing the car - the old radiator blew the top off - I knew it was coming - So I am in search of a new one.

Will post pics soon

 

Also I am only having to correct the fuel up about 7% and it is still half way into rich on the air/fuel guage. I have corrected the low side down 12% at 1000 rpm, man did that help my idle.

 

Pulley size wouldn't cause his boost ceiling at 3000 RPM. Its likely a boost leak or belt slippage. Belt slipping should be audible, but so should the boost leak.

 

It should be but I will only be able to hear it once I get my exhaust to a normal sound level.

 

pics!

 

There is something about your priorities that puts a smile to my face.

 

I will go by and take pics tomorrow and post tomorrow night. Car is at a buddys house, my neighbors do not like the exhaust volume.

 

how big is the intake into the turbo on a turbo II - That may be part of the problem with mine - I think I only have a 2" line going to the intake - maybe it is getting strangled after 3-4000 rpm

Could this be the boost ceiling?

Does anyone know the stock pulley size on a 1993 Thunderbird supercoupe?

I think I am spinning the supercharger alot slower than it is capable of.

 

No, 2in pipe is not your problem..

A mate of mine is making 200rwkw with 2in intercoolering piping.


Do NOT tune your car with the narrow band AFR meter...
very silly
take it to a dyno.

 

Would the car requiring more air at higher rpm be the cause of the leveling of the boost?

Also I calculated the max rpm of the supercharger at redline of engine (7,000 rpm) it is only 10,080 on the supercharger. I think it is time for a smaller supercharger pulley.

 

PICS !!!!

goto -

http://www.nesh.net/rx7

 

pictures of mounting bracket!!!