Webguy330i wrote:

"BTW did you check out the a/f pipe above? Is that standard for reading the post-cat a/f levels on a dyno?"

No that is not standard and I do not think it will give you accurate measurments. It looks like a typical O2 sensor mounted on a small pipe and then shoved in the tail pipe? The problem lies in how typical O2 sensors function, they actually measure the oxygen level at the probe tip compared to the O2 level outside of the exhaust. It does this by sampling the air through a small hole on the outer casing.
The problem with what you have here is the outer casing is also exposed to the exhaust gases to a slightly lesser degree. This will limit the true range of A/F ratios, which is exactly what I see on your A/F curve. Your range went from 12.5 to 10.5, on a pull like this with a stock car we usually see 14-15 to 9's.
Typical O2 sensor systems that measure from the tail pipe like this employ a vacum pump that sucks in exhaust gas from a long thin tube inserted into the exhaust tip. The allows the O2 sensor tip to be exposed to the exhaust gas with the outer casing well away from the same gases. Ideally you just want the O2 sensor mounted in the exhaust prior to the catalitic converter. The cat does not seem to affect the values very much, but it does cause a delay in the readings. So under a fast acceleration run the A/F ratio you see at 5k may have actually happened at the engine at 4.5K.

 

SS, thanks again for the information. I don't have an extra bung on the exhaust for another o2 sensor, how in the world will I get it upstream further in the exhaust piping? You are right, it's just a standard o2 sensor in a pipe clamped to the tail pipe.

Also I'm running a test pipe now with my turboback, so that eliminates the need for a pre-cat sensor.

The o2 sensor pipe my dyno operator has was provided by Mustang... I wonder if they have any alternative items to use. It would be ideal I suppose if I got my own wideband and welded a bung onto the test pipe as it is, wouldn't it?

I thought those numbers looked a little off... thanks for confirming that.

 

For dyno testing you could just use the bung after the cat, especially if your not running a cat anyway.

I am sure they have other options, while it is not ideal, it will probably work a LOT better if you rotate it so the sensor is pointing down so that the outer housing is out of the main exhaust flow. Not to mention the wiring/outer housing will be much happier.

Yes, if your going to do that put it on the down pipe, just incase you decide to stop being a polluter and run a high flow cat down the road, you can still do test and tune.

 

Excellent. I do plan on going with a cat at some point, just haven't scrounged together the extra fundage for it yet (I had to buy tires too!).

Thanks again for all the help.

 

Alright, I wanna see a 350whp and 350tq sheet along with mods needed.
I know your out there..............!

 

How to you disconnect power to 2 wheels so you can use a 2wd chasis dyno? A friend runs a mustang performance shop and has a 2wd dyno but does not know how to get a 4wd car to work on it, other that jacking up 2 wheels which seems very unsafe. Is there some easy way to disconnect power from 2 wheels and reconnect it when you are done?

 

i would like to know as well..i usually go to this 2wd for really cheap..and 4wd dyno cost alot more...something w. the transfer case right?

 

Hi all,
What is the difference between std and sae as far as a dynojet is concerned? I know that they are different types of correction, but what exactly is the difference? does one usually result in higher readings than another?

 

Pete from WORKS adjust it my P2 , now since i have a gauge . im able to see that im at 1.4 bar . with some adjustments.
car pulls a lot more at top end also air/fuel ratio is in the area of 11:1
where it should be, i need to dyno again but before that i will also add the WORKS Throtle Body , to see if achieve 310whp on 91 octane .
Dyno will be the judge .

 

My EVO with just the WORKS P2 flash on a dynojet. My next mod will be the WORKS aperture and then Buschur turbo back with Magnaflow. I'll probably stop there with mods and start modding myself by doing some track events/driving school.

 

Just did a run with my Auterra Dynoscan, (which I compared against my previous run on a Dyno Dynamics AWD dyno and found to be within +/- 5HP).
It was 101F, 20% humidity, 500ft MSL, 3rd gear run, 110 octane VP race gas, 25psi, 11.7:1 AFR, 18deg timing advance at redline (7850rpms):
387hp @7500rpms, 338lb/ft @ 4600rpms.
Not bad for stock turbo in 100F degree Arizona desert.

 

Its not the heat that will hurt you since the humidity is so low causing a dry air condition which is very good for making power. I have done my best racing in those conditions vs colder temps and very high humidity.

 

i dyno'd at pruven performance (they said it red low so i don't know)
286.6 hp and 307.1 ft/lbs at the wheels. on 93 octane.
mods are:
custom 3" downpipe back (stock downpipe, no cat, no resonator no muffler), aem ram air intake, 700cc injectors, 255lph walbro fuel pump, power enterprise boost controller set at 1.6bar, dynoflashed computer, act 2600 clutch.
best run so far is 12.614 @109.97. 60' of 1.732. best 60' of 1.68 that run was a 12.618@108.82. launching at 6300. act2600 is a GREAT clutch

 

200 hp mines is haha

 

EVO400 Ti turbo ,stock engine ,PIPER CAMS 11.5mm in/ex ,arp bolts ,GEMS ECU
pump fuel . evo400 exhaust manifold ,evo400 turbo elbow ,evo400 inlet manifold