1st things 1st. My car:
LT-8 ECU
13b-RE Cosmo
60 trim T04E .96 a/r exhaust side
OBX manifold w/40mm wastegate
An actual 3" FULL exhaust (Y pipe is 3", not like others where it narrows)
double pass rad
my IC is approx 23"x15"x3.5" H-mounted
550cc Primaries, 1600cc secondaries.
and some other **** i forgot. The car is about 75% done.


now I searched and could not find anything about getting better MPG. I have had about 2 months of tuning experience (i'd tune before work, during lunch, and after work, every day) And I'd like to say I tuned the car pretty good until it blew (all my fault). But I am about to take a long road trip in this thing, about 1300miles worth, and would like to if you guys have any suggestions, tips, etc for a 'cruise' tune, or nething i could do to get better MPG. LMK thx

 

BTW i do have a wideband, but its not installed yet, and I kno the ideal afr would be around 14.5

 

how did u blow your engine?..........too much timing?

i think cruising afr near stoich should be good. with egt around 700-720 degree C

 

that turbo saver works.

 

long story short, boost gauge was incorrect, and i was running 25 psi for about 2 weeks on the same turbo (60 trim) on my s4 motor. didnt mention before: car is 87 tii.

 

also, what the **** is a turbo saver. i searched on yahoo and got foodsaver results. im not trying to prolong the life of my food, just my fuel

 

woah 25psi on a 60-1.... didnt the microtech log tell you how much boost you are at?

i think u can turn on the decel and play with the rpmcrs to get some fuel economy but aint sure

 

Your normal tuning procedure should offer good gas mileage. Just tune the load bands first at steady state with no acceleration enrichment, and then tune the acceleration enrichment afterwards.

That would be stoich for most super unleaded pump gas, but keep in mind that fuel with a stoich AFR of 14.5 when burned at a 14.5 AFR will indicate 14.7 AFR on your O2 gauge if it does not have a user-defined calibration function. Anyway, a mixture leaner than stoich will usually yield better gas mileage at cruise, but you may want to start off at stoich and see how that works first before you go any leaner. The general rule of thumb for tuning the cruise AFR is to lean the mixture until the power drops slightly, and then add some fuel back into the mixture until the power goes back up to normal.

 

its not a 60-1, its a 60 trim. one is a little bit smaller than the other (i forgot?).
i was riding with a frend, he said he saw 25 psi on the laptop, (my gauge said otherwise). he also said it went from 0 to 25 psi in like a second, no progression
at all (i must have been at 5500-6k? in 3rd) im not sure if its a very fast spooling turbo, or the resolution on the microtech software sucks. part of the reason was because my wastegate was hooked up wrong too.

 

I am using the "matrix" mode and have it set up for maximun MPG at 65 MPH, 2500RPM and 10 hg (14.5 afr). If you are running "normal" mode, it can be set under "rcrs" screen as well.

 

Also....as long as you don't boost, you can run lower octane gas safely.

 

How many MPG are you getting?

 

what kind of boost guage was it?

how many miles per tank do you get?

 

It was autometer boost gauge. and I ended up flying not driving. I estimate I get ~240-260 MPT. This is on an untuned EMS

 

i only can get 10-12mpg untuned now sigh.......

 

You can run well under stoich, the car will let you know when it is too lean. Alot of reason the cars run stoich at cruise from the factory and not leaner is to save catalytic converters.

Now, running the car leaner will increase your water and oil temps. The other problem is just general heat in the motor, you do not want to be cruising for 300miles at a lean afr and get the motor all hot then go flog it.

Personally I have gotten around 20mpg at 80mph with a blown motor, and even better with a healthy motor. I am currently looking forward to 27ishmg on a stock AC Delco ECU at 80+ MPH

 

you got any tips/secrets: LT8

 

My car was happy with the techedge at about 15.5 - 15.7, it woudl start to lean surge around 16.0. The thing you REALLY have to watch is coming up onto boost and such with cruise this lean. I ran 2 maps a travel map and an in town map. My car was not a daily driver to around town milage didnt bother me and I ran my cruise around 13.7ish to keep the motor cool as if I was in the car, I was beating on it. On the travel map with the hellaciously lean cruise I richended up boost even more, took some timing out, gave it a little more fuel in the throttle pumps to try to combat the motor detonating from it having any hotspots in it from running lean.

 

so you're driving aroung with a base map? Jon (RXeng) brought me my LT10s from Australia and told me not to go into boost with a base map.

 

nope its not a base map......i tuned it with my plx m500 and an egt.... i got better around 18mpg now with my cruise afr around 13 ish......boost is still untuned cause it still reads RICH hehehe....... oh well im happy =)

 

I don't think I'll have the ***** to tune my own ECU yet. I got my friends LT8 to run pretty good till about 3000 RPM, but the staging was a little to tricky. I guess I need a bit more reading to do. I'll just leave it to Rolo to work his magic.

BTW: this is my next investment

http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW