Quest for MPG... lose the SCT/Bama chip?

combustor_d5 · Mar 22, 2015

Hey all I've posted on here before a long time ago regarding my friend's '94 GT. Well long story short the car is basically mine now, my friend moved out of the country and left it here with me I am stuck between buying it from him for cheap (he owes me :lipsrsealed

or selling it and getting a portion of the money. In the meantime I've been spending a lot of time driving it and tuning up minor things here and there; plug change, cap & rotor, new O2 sensors, smog pump delete... My main question, my friend bought one of those SCT 4-bank eliminator chips which I helped him install. I've been doing research on them and it seems like the general consensus is they don't do anything besides firm up the shifts (his is auto) and improve throttle response a bit, with a barely noticeable increase in WOT power. He got three 91-octane tunes (street, perf., race) which doesn't really make sense to me in the first place; these stock 5.0's have like 9:1 compression how can you tune it to run "better" on 91 as opposed to regular (85 around here at high altitude)? I have actually experienced pinging when I put 87 (midgrade) in there running on the street tune which surprised me.

So here's the thing, I took the chip out today to see the difference in how it runs and it feels basically the same except the transmission shifts WAYYY earlier (accelerating slowly at part-throttle) and quite a bit slower even when I shift manually with the pedal to the floor (with the chip it hits like a hammer driving this way :headbang

. Now I'm thinking, if I instead now bump up the base timing for a little extra oomph and keep the chip out should I get better gas mileage than with the chip? The car has CAI, BBK long tubes, off-road midpipe, 75mm TB (impulse buy courtesy of my friend I know it does nothing at this level) and 3.73 gears. Currently I have been averaging 15-17 MPG with mostly city driving.

On another note what's the best way to correct the speedometer with the shorter gears? Do I get a different speedo gear or is it just done through the computer?

rz5.0 · Mar 22, 2015

Bama supposedly has way better tunes now.. if he has tunes for life send it back see if you can get the v2 tune. . You need a Speedo gear for the speedometer .

combustor_d5 · Mar 22, 2015

rz5.0 said:
Bama supposedly has way better tunes now.. if he has tunes for life send it back see if you can get the v2 tune. . You need a Speedo gear for the speedometer .

Thanks for the quick reply... awesome, I was thinking of getting it re-flashed with an 87 street tune (for max MPG possible) and then leaving the performance and race tunes. Just looked at those speedo gears only $15 guess I'll be grabbing one of those!

Still wondering how a 91-octane tune works on a 9:1 compression engine though...?

rz5.0 · Mar 22, 2015

Increase timing

CC'S95GT · Mar 23, 2015

Changing out the VSS gear is only good for 3:55 gears. After that you'll need a speed-cal box to correst the speedo.

5-oh-MUSTANG · Mar 23, 2015

Ive wondered the same about that chip and its ocatane. Also, is ur idle higher with the chip? I idle around 1100 with the chip but my base timing is turned down all the way.

Addermk2 · Mar 23, 2015

My tunes are still WORLDS better than Bama tunes.

combustor_d5 · Mar 23, 2015

Took the car for a spin to get gas with the chip still out; filled up with mid-grade (87) then did a Sea Foam decarbon through the intake. It pings just a hair when floored but seemed to lessen up as I did it a few times to blow out the carbon, seems like it worked a little at least. Tomorrow when I get off work I will check the base timing, I've never checked it before and the guy my friend bought it from may have turned it up who knows.

5-oh-MUSTANG if your idle is too high you need to reset your base idle NOT your base timing they are totally different things... turning down your base timing will just make your engine run like crap.

Addermk2 I'm sure you can do a better tune than Bama but this car isn't really a project (that's my 1970 Plymouth Duster

) and I just want to get it running as well as possible without spending money on more performance upgrades. If I did end up keeping this car (read first post) I would use it as a car for my fiance to drive or as a backup daily driver for me so in that case I'm willing to give up 10 HP if it gives me a few more MPG... being able to run regular or at least mid-grade gas would be nice too.

KillNThrill24 · Mar 24, 2015

Bama sucks. Plain and simple. I had their tunes on my car for about 2 years, always wondered why my mileage had taken a massive hit. A few weeks ago I got sick of it and put the strategy tune on the x3 back on it. GO FIGURE. I went from 12mpg back up to 18mpg. I got them for free, but that's the only reason I did it. I'll never use another one of their tunes....

rz5.0 · Mar 24, 2015

KillNThrill24 said:
Bama sucks. Plain and simple. I had their tunes on my car for about 2 years, always wondered why my mileage had taken a massive hit. A few weeks ago I got sick of it and put the strategy tune on the x3 back on it. GO FIGURE. I went from 12mpg back up to 18mpg. I got them for free, but that's the only reason I did it. I'll never use another one of their tunes....

I had a crapy tune before. . A lot of people are actually saying how much better there tunes are now. . Got a different tuner now. .

KillNThrill24 · Mar 24, 2015

I'm not going to take a chance on it. It's only on my gt so I don't need anything fancy, just something that can turn the egr off (it's gone) and rear o2's (also gone). If I decide I want to maximize the performance, I'll get it on a dyno. No more canned tunes for me

rz5.0 · Mar 24, 2015

Data logging... alot of tuners do that and help your tune...

toyman · Mar 24, 2015

KillNThrill24 said:
I'm not going to take a chance on it. It's only on my gt so I don't need anything fancy, just something that can turn the egr off (it's gone) and rear o2's (also gone). If I decide I want to maximize the performance, I'll get it on a dyno. No more canned tunes for me

There are no rear O2s on a 94-95 GT.

toyman · Mar 24, 2015

combustor_d5 said:
Took the car for a spin to get gas with the chip still out; filled up with mid-grade (87) then did a Sea Foam decarbon through the intake. It pings just a hair when floored but seemed to lessen up as I did it a few times to blow out the carbon, seems like it worked a little at least. Tomorrow when I get off work I will check the base timing, I've never checked it before and the guy my friend bought it from may have turned it up who knows.

5-oh-MUSTANG if your idle is too high you need to reset your base idle NOT your base timing they are totally different things... turning down your base timing will just make your engine run like crap.

Addermk2 I'm sure you can do a better tune than Bama but this car isn't really a project (that's my 1970 Plymouth Duster ) and I just want to get it running as well as possible without spending money on more performance upgrades. If I did end up keeping this car (read first post) I would use it as a car for my fiance to drive or as a backup daily driver for me so in that case I'm willing to give up 10 HP if it gives me a few more MPG... being able to run regular or at least mid-grade gas would be nice too.

A stock to slightly modified only needs 87 octane if the basics are dealt with.

KillNThrill24 · Mar 25, 2015

toyman said:
There are no rear O2s on a 94-95 GT.

I know that. Lol. I have a mod motor. I'm just saying in general, Bama sucks :thumbsup:

combustor_d5 · Mar 26, 2015

toyman said:
A stock to slightly modified only needs 87 octane if the basics are dealt with.

OK this must not be the case when the base timing is bumped up, it knocks pretty bad if I floor it completely but running the stock timing seems to do alright. There are a couple maintenance things I want to do at this point, new fuel filter and a new thermostat with a cooling-system flush. I did some searching and limited fuel flow seems to be a problem on these cars, also the fuel filter ought to be replaced every 2 years or so well my buddy bought the car at least 3 years ago and I doubt the filter was ever changed. Also I notice when driving the temp gauge tends to fluctuate between 1/4 and 1/3 the way up it doesn't stay constant.

I'll see if my gas mileage improved at all with the chip out then go from there. I looked up the Moates Quarterhorse I really want to get one of those eventually, also a speedo recalibration tool but budget is real tight right now. Just sucks my buddy wasted $300 on "canned" tunes when he could have spent the same for an actual programming unit so we could tune the car in real-time. If the MPG went up I'll definitely keep the chip out for the time being and look into a shift kit. I swear this AODE shifts so slow and sloppy it feels like it can barely push the car; probably could use a rebuild with 160k miles :undecided:

toyman · Mar 26, 2015

One can usually bump the timing to 13-14* (spout out) and not hear a ping using 87 octane. If the HB is the original piece it may have slipped making the reading useless. Included in that basic tune is the need to remove and clean the battery to engine and engine to chassis grounds. All the sensors are subject to error if these grounds are not solid.

Tony Corley · Mar 26, 2015

Do the J-Mod on the trans instead of a shift kit, that will firm up the shifts.

Addermk2 · Mar 26, 2015

combustor_d5 said:
I looked up the Moates Quarterhorse I really want to get one of those eventually, also a speedo recalibration tool but budget is real tight right now.

I thought you said...

combustor_d5 said:
Addermk2 I'm sure you can do a better tune than Bama but this car isn't really a project (that's my 1970 Plymouth Duster ) and I just want to get it running as well as possible without spending money on more performance upgrades.

What is it exactly that you think I tune with?

Also, alot of that sloppy shifting, is the way the computer is programmed.

combustor_d5 · Mar 27, 2015

Addermk2 said:
I thought you said...
What is it exactly that you think I tune with?

Shoot I did not know that... guess I'll be hitting you up sooner than I thought :thumbsup: Seemed like there were other ways to do it I just assumed, I don't know a whole lot about these cars still

I forgot about the damper slipping looks like I'll have to check that now :blah: Tony Corley I have a '94 with an AODE that J-mod doesn't apply to me unfortunately. Also I need to check the condition of the transmission first, I would be surprised if it's still in good shape at 163k miles.

Going out to clean the grounds off now. I bumped the timing back a bit to 12* we'll see what happens. Also the last sensor I haven't yet replaced/checked is the IAT so that will probably happen today too.