legacycentral bbs

So yesterday I had to drive up to seatac for a work conference... 332 miles on the tank... When I filled up last night after I got back in town... it only took 12.9 gallons....

Thats 25.7mpg average for the tank!!! I was like

On the way up we cruised at about 80-90 as much as we could... On the way back... we made it 154 miles, in an Hour and a half... um... yea... we... well I... hella sped.... Average speed on the way back was 154/1.5 = 102.6 miles per hour...

Yikes... And I was on it most the way back because I felt like shit... and raced two Eclipse GSX's to. (and kicked their asses, might I ad)

Heres the full mod list...

Stock EM
Built 2.5L
98LGT DOHC Heads
vf10 turbo, 16psi
440cc Injectors
06-07 TMIC
3" TBE
K&N Air filter
IAC Delete
Charcoal Canister Delete
Rewired 02 Sensor, that is apparently working just fine lol

I bet had I slowed down and driven like normal on the way back I would have gotten like, 27 or 28.

Pretty sweet I though, just thought I'd share

Stock SS ECU and AFM? Injectors?


Nice mileage!




I'm really trying hard not to play big brother and tell you to keep the.................................

Yep, Stock EM running 440cc Injectors w/Stock MAF

And much appreciated

Thats crazy, are you sure your speedo is working correctly? I have a rebuilt long block but completely stock with no codes, vf34, 15psi, and driving "moddest" I cant do better than 18.5!!!

magicmike wrote:Thats crazy, are you sure your speedo is working correctly? I have a rebuilt long block but completely stock with no codes, vf34, 15psi, and driving "moddest" I cant do better than 18.5!!!

Yep, just fixed the cable, and I checked it on Google maps, to make sure it wasnt wayy off lol

Have you cleaned you MAF? O2 sensor? I take it you have 22t heads... I'm wondering if the heads have something to do with it, because Devan got great mileage on his LTurbo with the 22t/20g hybrid driving from ptlnd to idaho right after the build.

Here is a map of the total tank of gas and this doesnt include the extra miles to the gas stations and getting food, which I'm guessing makes up the rest of the miles on the speedo.


Link to map

Something is wrong.

I highly doubt anything is wrong...

What could go wrong that makes you get great mileage?

Your mileage compared to your specs doesnt make sense.

You have a motor with 300 extra cc's of displacement,440 injectors,16 PSI of boost,emissions deleting,all on the stock EM and getting MPG's that are like 50-75% better than many have reported?Maybe lol.

I havnt personally checked my own MPG's cuz i dont give a rats... but i know its MUCH less than that.I dunno.

My fwd N/A got between 25 and 27 with 80+ highway. Do you know your AFR?

The stock EJ22T are known to have a very poor BSFC. Just changing to more efficient heads opens up the opportunity for increased mileage.

The ECU learns how to trim the injectors very well (up to a certain point) if you have a working and responsive O2 sensor.

I still say, Spencer, your on the very lucky end of the spectrum. But I can see it happening.

Gi: Honestly, i think your wrong... Doug is pretty sure he's cruised and gotten about 25mpg, maybe once or twice. Another friend who has a built 2.2L w/98lgt heads and a Link G3 got 27 on the way back from the Tri Cities to Portland.

And stock cars, with restrictive intakes and exhausts were rated at 19 city and 25 highway.

I dont normally ever see this kinda mileage, normally, mixed city/hwy I get between 16 and 20 depending on how I drove for that tank.

When we got my old 93 Tleg, and drove from SanFran to Portland, we got about 25-26. All highway at 80+. Oh. And the engine had 115k miles of abuse on it.

And evolutionmovement: When I had a wideband on there I was cruising at about 14.7-15.0

Here is an original dealer sticker for a 93 Tleg



Just for clarification on stock mileage...

I guess.Just seems to me that with your setup you would be considered lucky to be running well.But to be running well and having top shelf MPG's to boot seems out of the ordinary thats all.

Gotcha.

And just so everyone knows, I borrowed Ralliteks wideband for a day and drove around with it, to see what my AFRs were everywhere... Basically, they were great... 10.5-11.5 under full boost, and about 14.7-15.0 at cruise.

These old ecus are better than we give them credit for... They just read to 02 and say, "Oh well, lets do what we gotta do!"

I got 23.5MPG on the hwy a couple weeks ago..so with some improvements I can definitely see 25MPG.

anyone notice a fuel economy difference with IC? You have to figure with more power there is less load on the motor and you do not need to gun it.

I;m sure intercooling helps to a certain degree (no pun intended lol)

And dave had an interesting thought... at 110 you are still in vacuum if your cruising... So your covering a LOT more ground with not as much fuel than being at a lower speed. So the speed could have actually helped a little.

smh0101 wrote:And dave had an interesting thought... at 110 you are still in vacuum if your cruising...

Wow, now that IS interesting!

Cool, I'm not too surprised.

I got 24 mpg coming back from the coast, and Iwasnt going slow..... And I am running 800cc injectors.

Sounds like you might be a hair lean while cruising. Not a big deal. I run mine at 15.5:1 on the highway with 45-46 degrees of advance. I get around 28 mpg highway during the summer. It drops off when it gets cold though, which is to be expected.