I just installed D1sc, 40# injectors,headers, and had Dyno tune, 8# boost, 419hp @ 5000rpm. It smells rich at low rpm's and puffs black smoke when I get on it.I did have some exhaust leaks which I have fixed, but what kind of mileage should I see if tuned correctly? Stock block,stock heads, stock cam.

 

Depends on the tranny, rear end, and how you drive it. But it sounds like your is WAY off, even if it's an automatic with a loose converter unless it is and you are talking about stop-and-go driving.

Rich

 

i had a ati blower p600b with stock internals at 8psi..i was getting over 20 mpg on trips. and it wasnt tuned at all really...my gas tank is 13.5 gallons i was gettin over 300 miles to the tank..and mind you, i wasnt driving the speed limit either i had 3.73's and a 6 speed. gears and tune..make a huge difference..im venturing a guess here but... a 383 with 3.42's in the rear and a 6 speed would probably get good mileage..especially on the highway.




Steve

 

I'm running a Vortech S trim on a stock bottom end. Ported heads, 224/236 cam and 40# injectors. With the 6 speed and stock 3.42 gears I'm getting around 22 mpg on the highway.

 

I have a P600b pushing 9 lbs (7 on the gauge) and on a recent road trip i got 25 mpg! 455 RWHP and 25 mpg....gotta love it!
I do have some pretty good tuning, i had wideband sensor readings from the dyno...Bryan at pcmforless got me pretty dialed in. Love the e-mail updates....

 

What is a good curve for the a/f ratio, any ideas?
I think, I'm at 13:5:1 off idle till 3000rpm then a/f drops to 11.5@ 5000+r's. This is an estimate, i need to find my charts, talk to tuner.
Should I add alcohol injection, and take out fuel?
Thanks for typically awesone ideas & response , great board!!!!!!!!!!!

 

Back in the day when I was running a stock motor w/ P600B and 8#'s of boost my Z used to get 22 mpg when I was running the stock program w/ MSD 6BTM set at 1.5 and 24# SVO injectors and the venerable FMU. After installing 42# injectors and ditching the FMU and MSD 6BTM I had Shalin Patel tune the car and the mpg went down to 20 but the car ran great.

I can't check mileage in my current setup as I haven't gotten the PCM recalibrated (went with 3.42 gears in my 12 bolt and the pcm still thinks I'm running a 3.23 gear) but I'd estimate 15 mpg.

Marc

 

Your O2's are providing feedback to the PCM to constantly adjust A/F ratio. It is always changing in closed loop, so you can't really say I want a constant A/Fat low rpm. If you were referring to the dyno chart, that doesn't even apply to closed loop fueling as your in power enrichment. To tune part throttle your going to have to monitor the learn numbers and make changes to the injector constant &/or offset table, and the MAF table. Sounds like you need a logger and some editing software.

Bill

 

I get 14 - 15 mpg on my setup.

PS: Any of you twin intercooler gus have pics of where you located your air filter?

 

My air filter is in front of the inner wheel well shroud, it pushes the shroud towards the tire a little. Not pretty, but it works.