Improving Fuel Mileage

[gsrteggie]

Hey all. I just installed the JRSC, and my fuel mileage went to shit in a hurry. This is not even with going into boost. I am thinking I will get maybe 200 miles to this tank, with 100 of those 75mph highway, (so less than 20 mpg)

I have yet to install my FP gauge, but I am running 11.8-10.8 a/f. I do not have a a/f gauge. I run a cartech fmu, aem fpr, walbro pump.

Looking at the archives, I saw that a BTC is improves gas mileage, and something about a TPS sensor mod (which may help with my vaccum detonation. I run a MAP mod, so what the hell is this?

[CROM]

I run a BTC, Map Mod, High Pressure Pump, 290cc injectors, AEM FPR...etc..and yes, I believe the BTC does help quite a bit.

I get well over 30mpg on the highway...and typically get 350 miles each tank.

[96IntegraRS]

The BTC lets you leave your timing at stock, which will increase your fuel economy ALOT.

Anyway, if you're playing the fuel pressure riser game (which has worked well for alot of us) you need both of these things (BTC/MAP) - and you'll be amazed at how much better the car will run.

Chuck

[fredtoast]

When I got my jrsc my mpg only dropped from about 28 down to 26. I attributed this to the fact that I was driving the car a lot harder. I only have the BTC, MAP controller, and high pressure fuel pump. I guess that stock timing is the key. What was your before and after mpg?

[gsrteggie]

I run stock timing now. Maybe I can do that because my car dumps a ton of fuel at the top end. My a/f at the top end is a 10.8 when it was a 12.0 and change stock.

I run a aem fpr, cartech 2005, walbro HO pump and a map mod. Stock timing.

I am thinking doing a V-afc to lean out my top end, but I am open to a BTC if it will allow me to not run as rich.

Right now, I think I am 18mpg, when I was 24 stock (usually city and most hwy driving, although roadtrips I usually get 30+)

[gsrteggie]

we'll see I guess. Next guess is that I my a/f sucks

[Petie]

Must be that the BTC is the answer. When I'm not in the throttle, my gas milage is basically unchanged from stock. I know this because I kept track of it before making any mods. Then, just after getting a lovely little document from our dear friends with the mirrored shades on the Interstate one day, I decided to fill up and see how my milage was doing if I was being good boy and staying out of the boost for the rest of the day. Much to my (pleasant) surprise it was almost exactly the same. Any milage you come up short on after you install the BTC can be attributed directly to your right foot.

[gsrteggie]

Um yeah....

Figured out why I had crap gas mileage.....

Fuel pressure gauge finally installed 2 weeks later.... FP reading @ idle = 80-90 psi.

So I am like WTF... I spent how much time tuning the car, to have it read 90 psi?????

They said the cartech was overriding the AEM, which is total bullshit. Seriously, how can a FP setting change drastically?? How can a FMU override a FPR all of the sudden.

So needless to say I was pissed, and they still charged me to fix the shit, which I was even more pissed about.... If they ordered the right fucking gauge in the first place, I would not have had any problems

Total invested = 3 hours @ $110/hr on dyno, + install costs that far exceed the time it took... (estimated $140) All down the drain. The dyno figures given could very well be at 90 psi throughout the range. They probably had to run that to keep it from detonating hard core at stock timing.

All for... Me to swap out the aem myself, which somehow is now running 35psi at idle again (so much for overriding), for the stock regulator that now runs 46-47....

My mysterious detonation in vaccum and check engine was pinging at low rpm, prolly due to the stock timing.

Looks like I got screwed.... and I know it. The shop didnt know wtf they were doing. All at the expense of my car, my engine, and my wallet.

Thank god for you guys, if it was not for you all here, I would be totally clueless about wtf they were doing.

<font color="#a62a2a" size="1">[ July 12, 2003 08:10 PM: Message edited by: gsrteggie ]</font>