I just got my new zietronix WB up and running and got some data logs to study. All I can say is WOW, why didn't I do this sooner. In one chip I have done more for WOT than 6 months of guessing. I was planning on building a DIY WB but things got too busy at school. It took awhile to getthe money together for this, but it has been well worth it. It's like my eyes have been opened.

Here are some examples of how close my "seat of the pants" tune was. All I can say is my butt dyno is shot....must be a dynojet.

WOT---- The AFR starts out at 13.7@3600 rpm and goes to 11.8 by 5800 rpm. Thats not good. It always had decent looking plugs, a little dark but not bad. Going rich on the top end covered up the way lean condition down low.

IDLE---- Cold start is surprisingly close. Then it goes to around 15.5-16 and some times leaner. You can actually watch the engine stumble a little when it surges lean.

PUMP SHOT---- This was tricky. It would spike way lean in the 18 range then shoot way rich in the 11.2 range. So I need to richen up my TPS AE and lean out my MAP AE.

PART THROTTLE--- Is right on, it ocilates above and below 14.7. You can really see how the ecm surges the AFR up and down around .2 points to keep the cat happy. I'm going to run open loop next and see if it still does this.

Over all this is really good news. I caught my way lean condition before I blew a hole in a piston. I have plenty of fuel up top so I have some room to grow with this TBI system. I'm lean down low so I have't run out of adjustablitly at idle. It's the best 300 bucks I've spent in a long time.

Setup:
747
454 TBI
70 PPH injectors@ 21psi
RPM intake
416 heads
Comp Extreme 4x4 218/.462 226/.480 with 110 lobe sep
350 9.5-1 200 psi of cranking pressure
dual 2.5" exhaust with x-pipe
ran a 8.92 @77 in the 1/8 with carb and smaller cam
700-r4 trans with 2000 stall

 

Congratulations. Welcome to the land of the sighted. Now the fun really starts.

 

One of the best investments I've made.