Mazda Rotary Club

Here\'s the video of my car on the dyno at RotorStock 5. It ran @ 228.2 BHP. I was hoping for more but seem to be loosing boost and running a bit rich in places too!

Here is the Dyno print out I got.

when i click play it says this video is no longer available

I\'ve just uploaded it. It might just need a minute to sort itself out.

seems to be working now.

Thats proper fecking lean in the midrange!

Yeah I was talking to T2REW and he reckoned it should be a fairly straight line all the way along between 11 and 12. I\'m not too sure as I\'m just learning about all this as i come across it. I do know it shouldn\'t be that high though!

Boost is quite high in the midrange, (by no means too high) dies off but they all do that, the turbo\'s simply are not big enough to flow higher boost at the top end. Its prob really struggleing to pull cleanly through the rev range low down. That fueling really is past the point of slightly off though, to the point of.. really not good.

Yeah hopefully Grinder has something for me that will sort it out. Get looking for it Stu.

who me ... :D

Yes you. When you get chance buddy will you dig out that Apexi fuel meter and let me know if you defo want rid of it.

how can you tell its lean in the midrange ???

i might beable to get my hands on something else which will do the job aswell :D

You mean you might know someone who has something ;)

Those AFR\'s look to be going \'STOICH\' - as in ideal mixture for all fuel burnt in the mid range - that\'s when the stock lambda will do closed loop fuelling - so you might expect that - I don\'t think it\'s lean though. After a certain point and certain boost, the ECU will just start working from fixed maps and then you get much richer AFR\'s because the ECU will start dumping fuel to avoid knock and aid cooling.
 
There is a blip towards the lower RPM\'s where it suddenly runs horribly rich - that\'s sort of wierd, but could be to do with fuel pump resistor or fuel pressure or something a little odd like that.
 
Generally you\'d expect a nice curve - starting rich at idle, gradualy going towards 14-14.7 in the low to mid RPM\'s then after 3800, it should start to get rich - possibly getting a little leaner again at the top end as the injectors can\'t keep up with air flow (although with a stock turbo that\'s not too likely)
 
The boost coming on so low down would explain why you\'re getting good times on the strip - that will make a lot of torque low down in the rev range - shame he didn\'t give you a torque curve sheet as well - would be interesting to see that.

Quote from: Prof;523702I don\'t think it\'s lean though.

14.5:1 around peak torque isnt lean on a turbo charged rotor at 14psi?

Quote from: Prof;523702Generally you\'d expect a nice curve - starting rich at idle, gradualy going towards 14-14.7 in the low to mid RPM\'s then after 3800, .

On "boost" at peak torque 14.7 afr is too lean, needs to be at least 12 afr at anything below 10 psi.

You should only see 14.7 afr when you are cruising

My bad :spank - just realised his boost comes on max quite low down - so yeah - he\'s getting quite high AFR\'s for 14 psi.

For \'quite high\' I would read \'rebuild waiting to happen\'. 14:1 anywhere but on cruise on a turbo charged rotary is asking for apex seals to leave rotor housings at their earliest opportunity.

Now your scaring me. Think i\'m gonna have to get the fueling sorted and pronto.

 Stu sooner the better mate!