LA3 and mpg

[BrianO]

I've read tons of threads of people upgrading to the LA3 ecu from the 88 T-birds. The ratings on those cars were 190hp and said they got 24-28mpg..

most of you have upgraded for the power, but has anyone seen a gain/loss in mileage? that is my main concern. efficiency is my goal here along with reliability.

I've read there is an instant power increase across the rpm range, but nothing about mileage..

[NavySVO]

With power comes more fuel. More fuel comes with less mileage.

Keep foot out of it and you will keep some efficiency.....but why have more performance if you are keeping your foot out of it.

I understand that you want to keep it getting good gas mileage, and not trying to be a S/A, it's just a contradiction in terms.

[svobrown]

The turbocoupe I had got 30 mpg. WHen I changed the svo te to a LA3 it stayed the same. But I never tried to get good mpg back then.

[BrianO]

with gas prices hitting 3 bucks and diesel at 3.50.. I'm about to start riding a bicycle the 40 miles to work each day.

[svobrown]

No kidding. I'm putting my new block in and turning the boost down. Trying for 30 mpg. Got all my light weight stuff in it and 3.55 gear with the 88 tc tranny in it. Also got the ranger cam for low rpm power. Next thing to do is narrow tires.
The only real way to get good mpg is stay slow or ecu and control the a/f. All the other stuff just helps some.

[SVOeric]

the injectors are bigger, but if you're still running the same amount of fuel, the milage should not change.

If anything, the 87-88 comps had better manners, and fuel economy than the old 84 TE's

[BrianO]

I'm hoping so!

[caroth]

Looking at the base fuel table for the PE and LA3, the open loop values are identical for normal cruis conditions below 3500rpm

http://rothfam.com/maf/tools/basefuel.jpg

[BrianO]

Looking at the base fuel table for the PE and LA3, the open loop values are identical for normal cruis conditions below 3500rpm

http://rothfam.com/maf/tools/basefuel.jpg

good info, I've not seen any tables for either in my searches. thanks!!

[IXLR8SVO]

I had a couple of TurboCoupes and they all had the LA3. I could easily average 30mpg and even get into the 33 to 35 range from time to time.

Problem being, when I did this, I was cruising at 55mph! When these cars where built, the automotive engineers had to achieve their mpg ratings at the benchmark (national speed limit) of a 55mph cruise. When I lived in the mid-west and the max speed limit changed from 55 to 75, my mid thirties mpg immediately dropped to mid twenties.

Simply swapping to an LA3 is not the silver bullet for better mpg. In order to get better mileage from your SVO, you will need to consider including a rear end gear ratio change.

Cruise at 55mph one day and make a note your average RPM. Then cruise at your real world cruising speed and again, make a note of your RPM. Now its time to take a hard look at your rear end ratio and figure out what it will take to get your real world cruise RPM down close to what it was at the 55mph mark.

[SVOeric]

I believe Brian already has swapped rear end gears.

[BrianO]

yes I did.. back to factory 3.45's

[NavySVO]

good info, I've not seen any tables for either in my searches. thanks!!

I thought Pat just posted these about a month or so ago

[BrianO]

maybe so, I don't remember seeing them, but regardless who posted them it's a good help.

[Bouncer88]

Yeah I just bid on an LB3, there is an LA3 up for auction on evil bay too.