DarkBrew

Your calculated load hits close to 100%
Ours never get close

wcs

iTrader: (2)

Hey yeah ... um I see that now...
Well what the hell would cause that?

I'm mean isn't the dyno responsible for the load?

I think you can still reach a 100% load even if your g/s is low.
I can't recall at the moment how load is calculated....... haven't had a coffee yet <yawn>

wcs

iTrader: (2)

Calculated load uses
Engine Displacement, Measured Air Mass and Engine Speed

Darkbrew maybe we should try swapping out your MAF?

DarkBrew

I would have thought the mixture would go way off if the MAF was bad.... The MAF cal done on the dyno should be good, shouldn't it?
The dyno says I'm way down on power....
Still thinking SSV.
BTW, the car idles really nicely with everything cleaned up.

RotaryMachineRx

iTrader: (1)

See I don't think my car is down on power but that could be a combination of maybe it has been down since I've owned it and still amazed by how the AP really livened the car up..... any of you two know the accuracy of the Dyno program on the AP?

DarkBrew

Not sure of the accuracy but I can give it a try tonight since I have an actual dyno run to compare with.

My car feels strong and runs well in normal driving but the dyno doesn't lie! Above 6K the HP and torque curves are just wrong!

RotaryMachineRx

iTrader: (1)

I agree those numbers are quite disheartening... I'm amazed that the AFR readings on that dyno are so lean though! I tend to dip into the 10.9 range at WOT at certain rpms but I am only running MM's base NA map for now, I'm assuming you have had some custom maps sent to you already?

That be great if you could see what you get with the AP dyno so I could get a comparison and see it's accuracy. WCS could you also do a couple AP dyno runs and let me know what you get?

wcs

iTrader: (2)

Sure I can do a couple of runs.
I've used it before and didn't feel it was too accurate however that being said I do NOT know if it is calculating the hp and torque at the wheels or at the crank.

RotaryMachineRx

iTrader: (1)

I guess we'll find out when you log yours... you should be around 237bhp if I factor in a 21% drivetrain loss. 200*.79 = 158.... so if it is bhp that means I'd be sitting at 158 whp, hopefully it is measuring WHP then. But for some reason when I did my pulls I thought it said horespower at the wheels somewhere, but I can't remember and I'm at work.... I'll hit up the Cobb website.

RotaryMachineRx

iTrader: (1)

Didn't specify on Cobb website

wcs

iTrader: (2)

Cobb Dyno runs ...
Settings
Weight run 1 = 3389 lbs
Weight run 2 = 3589 lbs

Gear 4

Start run = 4000 rpm
End run = 8750 rpm

results 1 = RPM = 8429 Tq = 870.81 Hp= 1418.13

result 2 = RPM = 8036 Tq = 233.6 Hp = 357.43

wcs

iTrader: (2)

I guess something is a miss.
If you review the log files you can see some strange reading in the upper rpm band. My guess is that the data bus just can't handle the polling frequency from the cobb.

Anyways it would still be good if it was consistent even if it wasn't correct.
That way you could gauge an improvement.

For example even if the cobb just gave results in the number apples ....
As long as you keep getting the same number of apples then you have a standard.

Make a change to the car and see if your apple value changes.

Alas this doesn't seem to be the case.

To many variables ..... road slope, weight, wind, ....

DarkBrew

I did a run in 2nd from 2000 to 8950 RPM

got 395 HP and around 300 lbs of torque up over 8000 RPM

I wish!

Maybe it has to do with gearing??
Edit:
I'll have to download my datalog...

Looks like WCS made 228 @ 7800 RPM on AP

RotaryMachineRx

iTrader: (1)

yeah i didnt data log my dyno run but the max that it displayed on the AP screen at the end was between 195 and 205 for 5 different pulls, it got me thinking that it was pretty accurate but I dont know if it averages it or what... I'll have to do a pull and data log it to see for sure. I guess from all this logging of different parameters we still know one thing, Darkbrew and I both have low g/s haha.... this is rattling me

shaojie1984

Just go to a real dyno,the cobb dyno is not accurate, too many things will affect the result.

DarkBrew

So I did some reading and checked out a few things.
The VDI and SSV valves move freely
But we could still have bad air solenoids, actuators or bad control signals. Must get a vacuum tester.
Next thing is to pull the APV motor to see if those valves are moving freely... Then check the motor function.

wcs

iTrader: (2)

^^^^ Agreed shaojie
That being said, dyno shops are rare when you live out in the country (me)
And unless you could keep using the same stretch of road over and over without getting thrown in jail.....

Also I'm not sure how Cobb does the math, does it consider the gear ratio correctly, what is the weight of the car and how accurate do you need to be with the weight value.

I'll try some 3rd gear pulls today.

It would be nice to lay down some steady repeatable runs. Then make a change and see what the delta is from the new value.

RotaryMachineRx

iTrader: (1)

haha all that seems a little over my head to do on my own. I'm almost tempted to do a NA dyno for comparison when I get back to Saskatoon from my summer job... I'm also out in the middle of nowhere; but $100 or whatever it will be to dyno is pretty pricey for a University student.

I thought you were thinking it was the SSV valves; what do you mean by they move freely? You actually got in there and checked them?

What about the VDI sleeve valve.. maybe we are just loosing g/s in the last 1500 rpm up top

RotaryMachineRx

iTrader: (1)

I was on a fairly flat section of secondary highway where I was able to turn around and use the same 500m stretch each time (it's not hard to find out on the prairies)... out of 5 runs they were all consistently within 10hp of each other (195-205hp). All 3rd gear pulls with my weight set to 2999lbs so the hp reading would have been a bit lower just from using a lower weight as well.

DarkBrew

Yeah, that's what the APV does... 7250 and up.

The SSV is air actuated and I was able to move the mechanism easily. Also the VDI actuator moves freely too.

There are pictures in this thread. http://elworth.info/html/rx8_fuel_injection.html

RotaryMachineRx

iTrader: (1)

^ Yeah I understand what all the valves do, just physically gettin in there to check them... I'd have to read up on it all.... and I think VDI is 7500 to redline. But I follow ya, all that is left to check is the APV's and if those are moving freely then solenoids and actuators. I guess there is potential for a small vacuum leak also.

DarkBrew

Here are my logs plotted against logs from a healthy RX-8
Recorded on Dyno day.

wcs

iTrader: (2)

Interesting.
It appears that the g/s separates around 6500 rpm

Could it be possible that its only a partially failure of the SSV?

DarkBrew

Well, I'm going to use my new vacuum tester to verify operation of the SSV and VDI including the hoses.
Also we'll pull the APV motor later to see if it's working and the port mechanism moves freely. (need to put the car on stands again!)

wcs

iTrader: (2)

^^^ LOL
Ok I let you do it this time, nice and easy