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EggyD 06-22-2011 08:13 PM

D15B with Neptune RTP
Hey guys I got my Neptune setup about 2 weeks ago and am on my second tank. The first LEAN burn attempt was 38mpg. Not as good as Ive seen people getting. my 2nd tank looks to getting a lot better. Im at 240 miles and the gas gauge is at almost half tank. Is there someone here that can read my tune and give me some pointers? and also what should i change? like Disable Closed Loop, fan control in gauge at 180 above 50mph ext.... any thoughts are greatly appreciated. Thanks

EggyD 07-31-2011 05:07 PM

It's been a while know and still not very happy with the lean burn tune. Best attempt is 43 mpg and I know there's people getting way better results. Any tips would help out slot. Thanks

Tygen1 07-31-2011 10:27 PM

What AFR are you running? How fast do you travel? Do you have an instantanious MPG display, if so what are your typical readings? What other mods do you have to your car? I assume you are running a wideband, which one?
Give some more details and I will help where I can.

I'm running around a 17:1 AFR, driving 50-55mph with aeromods and very LRR tires. My instant readings are in the mid seventies with this set up.

EggyD 07-31-2011 10:42 PM

I have a innovate lc-1 running at 19.5 afr ( no b.s. ) while cursing 45-55. I have a jdm d15 single stage vtec with a Skunk2 intake manifold tubular header and 2.5 exhaust. Lowered on blox coil over sleeves and agx shocks. No ac no ps other than that it's stock. And of corse the Neptune rtp. I don't have a mpg gauge although that's on the list when money allows.

Thanks for the help.

Tygen1 07-31-2011 11:11 PM

Don't worry, I don't believe you are trying to trick me on the AFR.
One thing you gotta consider with running lean is that you need to reduce your load. Big wings, wide sticky tires and the like will have a large negative impact. The more power you need to make to propell your car down the road, then the more fuel you need. That's why I can do so good at only a 17:1 AFR.
Even though I see mid seventies while cruising, I can average just above 50mpg on my regular commute, so you also need to consider the way your drive, the route you drive, etc...

The key ingrediant will be the Instant MPG Gauge. Without it, you will never get your tune right for best mpg while lean. Right now you are just guessing at all of your parameters and they can not even be educated guesses because there is not much of a knowlege base for running this lean. I'd suggest you get an MPGuino imediatly, back down on your AFR and focus on learning how to get a more convervative AFR. You are more likely to suceed this way and learn how to make a tune that works will with lean AFR's.
If your able to tweek your injector pulse widths and timing on the fly, you can just monitor an instant mpg reading and you will know exactly what parameters are needed.

Hope this helps!

Tygen1 07-31-2011 11:13 PM

Oh yea, I have to add that at 45mph, I'm at 16.5:1 and getting high seventies or low eighties and at 35mph, I'm at 16:1 AFR and getting low nineties. Leaner isn't always better, you really need to expirement and think outside of the box.

EggyD 07-31-2011 11:30 PM

Great point I'll report back after I get the mpgunio.

mwebb 07-31-2011 11:54 PM

exhaust pipe diameter is too large
assuming 3000 rpm as approximate upper ceiling of cruise , your exhaust pipe diameter is over 200% too large ,
and it does matter
begin here | Calculators | Exhaust Pipe Sizing

read this thread all of it .
the MPGuino will help immensely as well

Tygen1 08-01-2011 02:03 PM

I wouldn't split hairs on exahust pipe size. While I'm sure it could be optimized for FE, I don't expect that to be the need in this case. I have an oversized exhaust pipe as well. I like to use my car for more than just good FE. Even when I go drag racing, I am still getting great FE :) I want my cake, with frosting and I want to eat it too! Lean Burn is the frosting :D

EggyD 08-01-2011 06:54 PM

Yeah thanks for the info guys will see what my instant mpg is when get my MPGuino. I'll be able to tune it better from there. Where are y'all mounting it at? I seen a pretty slick setup under and behind the tack. Dose any one know who did that?

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