I am driving an 04.5 Automatic G35 Coupe with the following performance mods:

High-Flow Cats
Borla Dual Exhaust
Plenum Spacer
Unorthodox Crank Pulley
Pop-Charger
Z-Tube
Grounding Wires

With all of these mods, my mileage is much worse than it used to be. It used to be around 21-22 and now it is 18-19.

Also, power does not seem to be equal throughout the shifting. It feels jerky at first, fine in the midrange, and the top-end takes a while to kick in.

I know my A/F ratio is way off and would like to fix it. So it is either an ECU flash like Technosquare or an air/fuel controller.

What do you guys think? Do I need the reflash and will I see some big differences? If you have the Technosquare, please give me your opinion.

Thanks.

Jason

 

i heard reflashing definitely will help you get the lower end torque back at such set up. ( i have very similar set up, and ive talked to technosquare people b4... ) i didn't reflash mine yet bc it will make the gas mileage even worse... i know i have to get it done someday tho...

 

I have some of the same mods as you do and the Technosquare full flash will help with your performance. The Technosquare flash will make the air-fuel corrections for the mods that you have. The flash works. The guys at Technosquare know their stuff. I had it done and noticed the differance before the flash and after.

 

Jason,

The flash should also help bring your fuel mileage back to where it was before the mods. But I will also tell you that you will be more inclined to put your foot down feel the difference in perfomance (and that will always lower you mileage).

 

is this true? can you explain how?!? i thought part of reason for reflash is to give more fuel @ lower rpms... i guess i am way~ off if what you say is right.

 

How do you "know (your) air fuel is way off"? These cars vary by quite a bit from vehicle to vehicle. Did you dyno before and after your mods on the same dyno?

With headers, h/f cats, plenum, intake and exhaust mods I was only 1 point higher on the A/F curve than a bone stock car in my same model year (albeit not my car as the baseline). Others had 1/2 the mods I had and were EXACTLY THE SAME as the stock car. Point is, that these cars are fickle and all seem to vary, especially by model year.

 

Neffster,

I had my flash done at Technosquare. The ECU was flashed programed and tuned to the mods that were on my "G". They test drove the my "G" with some sort of diagnostic device, Took the readings from the drive and tuned accordingly. It took about an hour and a half and a few runs to make the ECU adjustments to get the proper air-fuel mixture throughout the full drive range. Brian at Technosquare did my flash. Brian also said the each vehicle is different according to their mods.

 

If I lived within driving distance from TS I too would pay for the reflash. It's the 3000 miles and the mail order tuning that kept me from dealing with them.

 

They did a good job reflashing my Fx45 ecu via mail

 

Exactly what I was going to say...
if everyone with bolt-ons had their A/F ratios "way off" we'd all have to get fuel management...

Also, before people spend their money, has there ever been a clean-cut conclusion to the dyno proven hp gains? There seemed to be pages of people disagreeing back when I looked into this.