Dyno A/F Question

[Tungsten]

I had my GT at the dyno and they told me the "sniffer" that goes in the tail pipe is not an accurate way to measure A/F on the GT because the cats affect the readings. They suggested putting a connection point in the headers to get the A/F readings. I don't understand how you can accurately tune without accurate A/F ratios but before I have them drill a hole in the headers and add a connection point I wanted to ask the experts.
Thanks
Don :confused

 

[50 BMG]

Are there any 02 bungs already in your headers?

 

[Tungsten]

02 Bungs

Nope, not unless they came stock that way and we have not seen them. There are 02 bungs for the cats that feed the sensors, but they tell me that they won't work.
Don

 

[QKSTNG514]

Dyno

Remove the Drivers side primary O2 (Upstream) and install the wideband sensor there.

Do it all thei tme.. Works great..

TonY G

 

[lthlvpr]

The A/F ratios may be slightly different post cat vs. pre cat. In addition, when you tune on a dyno you are not moving, and air around the car is not moving both of which can impact incoming air in the airbox, coolint, IAT, etc.. I do recommend you use the pre-cat sensor for optimal tuning, but I also recommend the purchase of a wideband sensor that you can read before the cat to monitor A/F at different speeds, etc.. on the road (real world driving conditions).

 

[Tungsten]

Primary 02

Tony, thanks for the info. Is the primary 02 before the cats?
Don

 

[barondw]

Next time I have the rear bottom panel off I will show post a picture showing where the bung was welded in place for the wide band sensor on dyno tests. Also I have an access panel in the bottom panel for easy access.

Dave

 

[californiacuda]

Westech dyno in Mira Loma now has equipment from Innovate that will be able to monitor a/f from each cyllinder individually, requires 02 bung in each cyllinder exhaust pipe about 12in from heads. Seems like a great idea, giving the ability to see how each seperate cylllinder runs.

 

[Dynotech402]

From the chassis dyno...

I've run the chassis dyno @ Westech during all the GT parts testing and development with Accufab in Southern California. The cats ONLY affect the A/F reading for a split second when you go to WOT. This is when the cats release their O2. We ran a "sniffer" with a vacuum supplied via shop air to get accurate readings during low rpm testing when there is very slow air speed across the wideband. As the rpm increases, that problem isn't a factor. Accufab now has a stainless X-pipe, Inlet stiffener, throttle body, and a complete tune available for the GT. They also recently finished a twin-turbo kit that was run in the standing quarter during the "Silver State Classic" in Nevada where the car ran 210mph!! The parts are top quality and the performance is not for the faint of heart!!

 

[fjpikul]

No offense, but didn't that car burn a piston during the run?

 

[Dynotech402]

yeah, it did but the problem wasn't related to any of the Accufab pieces or the tune, but a fuel delivery issue, inheirant to Fords fuel system design.

 

[Bart Carter]

yeah, it did but the problem wasn't related to any of the Accufab pieces or the tune, but a fuel delivery issue, inheirant to Fords fuel system design.

Ah...sounds like something we would like to know about.

 

[BlackICE]

If there is a problem how does Piko's car have 1000+ hp with the standard fuel system?

BlackICE

 

[Dynotech402]

Consider this..

I never said that the stock fuel system couldn't do the job, obviously it did. You always have to look at the application. You can run an engine with 12.5:1 compression on the street on pump gas, just as long as you don't go WOT. It's the difference between static and dynamic compression. Without WOT the engine never sees the volume of fuel/air to reach max compression. Listen, the point is, I believe it was the application, coupled with the type of event(distance and constant WOT load) that forced the problem to show its ugly face. I'm sure there are plenty of guys out there makin killer power with the same available volume of fuel, but for how long, at how much load, and at what pressure?? Thumbs up to "Piko", I don't know anything about him.

-Hammer Down

 

[BlackICE]

Piko is the guy from FL with the twin turbo GT. I think he is going for even more power now and needs an upgraded fuel delivering system too. The car seem to do mostly drag racing so maybe that is why he didn't run into a problem.

BlackICE

 

[piko6]

NAAA... i hit 200-220 and even more a lot of times....

WOT is what i love to do.. i might be a little more lucky i guess.. i have got 4000 miles on beating this car so far it is running strong also i use 115 octane

i never used regular gas in this car yet... i think 115 octaneis the big difference here..



thnaks

joe

 

[Dynotech402]

Right On...

You're makin some serious power to hit those mph #'s. Good deal. I think the 115 octane is definitely saving you. With the boost you must be makin to run those speeds, I wouldn't ever run anything less than, lets say 114VP or Rocket Brand, which is the old 76 Racing division.

-Checker or Wrecker!!

 

[dbk]

You're makin some serious power to hit those mph #'s.

Not that Joe's car doesn't make insane crazy power, but a stock car will hit 212 anyway. I have proof on video using a vBox.

 

[californiacuda]

How much distance does a stock car need to get to that mph #

 

[Specracer]

Nardo, that is a great vid right DBK?