DMBfan

So I went to the dyno with some friends on Saturday and did a few pulls for fun but came out scraching my head in the end. The first pull I did was in 5th gear (1st attachment) and around 7250 RPM the HP dropped off about 20 as did the torque. I did my next pull in 4th (3rd attachment) but didnt run the RPMs up as high and it looked like it was about to do the same thing. The 2nd attachment is the two pulls together and you can see it happening on both.

I've done some searching (not claiming it to be extensive) and can't seem to find any dyno that looks the same way. My 8 is bone stock. It was manufacture in April of last year so doesnt look like I need the new flash.

Any way was wondering if anyone had seen anything of this sort before/ knows what could be causing the problem.

Thanks in advance

rotarygod

Your auxillary ports should be opening right there. It looks like they aren't. The reason I say this is because the engine should be getting more air there since it is getting more fuel. It doesn't look like it is. You didn't take the last run up that high but you probably start running really rich at that point which is why power actually goes down. Combine this with the existing ports not being able to supply enough air for that rpm. Have this checked out. It is a small electric motor mounted on the lower intake manifold. It might have gone bad. That's my best guess.

voyager18

hi rotarygod, i face similar problems but my dyno chart shows a steeper drop. i'll see where i can scan my dyno and show u guys what i mean. can you elaborate further when u mention that the 'small electric motor mounted on the lower intake manifold' could have gone bad...? do u have diagrams/pics to show where it is? Thanks!

DMBfan

So I did some more research prompted by what rotarygod said and this is what I found.... I was looking at the Renesis Rotary Engine Design and Technology Technical Training Program that I found on the site.

I believe that the auxilliary port valves open at 6250-7250 RPM. Right at 6260 on my 1st dyno chart you can see the little did in HP and i think it is a sign that that valve is working. I think it is Variable Dynamic Intake(VDI) valve that isnt working. Its supposed to kick in at RPMs greater than 7500.

I'm going to check out the VDI as soon as I get a chance to see if thats the cause.

G8rboy

It sounds like your VFAD 'flapper' isn't opening... might want to check the vaccuum lines and the solenoid on the back of the airbox that triggers it.