If you have LT1 Edit, some guys lockup early and add (or is it take away?) timing. Check out some of Christian Millard's thoughts on the matter. He did a whole test and all LOL...

You could set the shifts sooner and lockup sooner. I tell you what, driving habit can drastically affect your mpg. I'm not exagerating... it can make a world of difference.

 

I don't really get it either. This past summer before my tuneup, I would get around 140 miles a tank in the city and after doing a complete tune-up, including plugs, wires, O2's, and my PCV valve, I still only get around 160 a tank. What else could it seriously be? I have no performance or miss issues and it idles smooth. Would a new coil help?

 

well, yesterday I read my emissions on the dyno at my job and the hydro carbons was at like 14 and one other thing was low. one of the mechanics said it looks like a misfire..... so I bought 8 acdelco plugs(non platinum) and I bought a new fuel filter, hopefully this will help out, the pld plugs hade built up a littlebridging on the prongs and carbon deposits...however there was one that was terrible, it had alot of carbon and was fouled, the reason I think this happened is because my car ran with that wire off for like 10- 15 min...so I think that in that time period the plug got ruined.....
next weekend I think I'll do wires and o2's


ohh yes, and if there is some sort of special tool they use to change our plugs then please let me know, cause I thionk it's rediculous that it took me about 3 hours alone to do the right side....It had to be the most hardest and annoying thing that I've ever done.

scyzoryk, i live in middle village right by juniper valley park

 

My converter locks up at 46mph and I don't get that kinda milage.

 

Who told you all of that? I've looked at a Jet stage 2 program and it had almost nothing done to a/f ratios.... and as far as I know, no program out there can change the lt1's flash programming on the fly....

Jonota

ps I'm getting upper 16's, exhaust manifold->y pipe leak on drivers side right in front of the O2, previously getting aroudn 21 in town, 27 on the highway, M29 w/3.23

 

Unfortunately, (not) I already have the 6 speed. And I've already taken into account my driving habits. This engine just plane runs rich. When I pulled the plugs they were all normal and the same, except for the carbon. If this were on my carb'ed engine I'd be rejetting it. This is on a car that is vertually stock, doesn't even have headers yet. And runs perfectly, no codes ,no lights, no miss or hesitation. I just find it hard to beleave that this car should ever get 13mpg. Of course it does weigh almost 4000lb. so maybe I'm just not being realistic.

 

offhandedly here, does your car have a loud popping noise on decelleration?

Jonota

 

I have the TOLT without the "Cone". So yes, it growls quite nicely on decel. I know there you're headed here, but I don't think it's off nominal. Not that it couldn't be, but I have a lot of experiance driving cars with different types of exhaust, and I don't find this one to be unusual.

 

well I might be headed somewhere a little different, as I had a problem that was making my mileage HORRIBLE that NOONE could diagnose until I stumbled upon it one day. have you hooked it up to a scanner to see what your fuel trims are? if you happen to be saying you're running super lean, I have a test for you.

On my car, the check valves for the AIR system failed, causing the manifolds to suck in air at all times through the intake system. This caused a loud popping sound on deceleration. After removing the AIR system, and plugging all it's holes, the popping noise went away, and my fuel mileage went back up. Now I have a manifold leak that's dropping the mileage back down...

Just a thought

Jonota

 

No scan yet. I'll get there eventually. Thanks for the info. I don't think this is the problem but it's definitely worth checking.

 

I think it may be my opti, cause I changed my plugs and fuel filter, and didn't fix, and from the high number of hydro carbons it's putting out it looks like a dead miss, plus every once in a while the car will studder when I push the gas....I will know definate tomorrow though

 

No one person has told me that. I've read a few things and that's just my impression of what the Jet 2 module does. What does it do then if not that?

 

First off, that's what all of the "performance module" companies say, or something very similar. For our cars, you can easily MONITOR all of those things using a scanner, which there are several out there. HOWEVER, changing the programming on the fly is something that hasn't been done yet (to my knowledge). Most of the performance module change some part in the programming to attempt to get you more power. In our cars, a quick and easy way to do this is to modify the spark advance tables, and the WOT target A/F tables (these are not their names in the program). Having looked at a Jet stage 2 performance module's attempt at changing the lt1's programming, I can tell you it did very little. As do MOST of the performance modules out there. I could look it up specifically and tell you, but off the top of my head I would say no more than 3 cells of the spark advance table were changed, and if I recall, NOTHING on the a/f ratio tables.

Secondly, I ask you this: have you done any testing that conclusively shows ANY benefit. Often times, we get a little excited after doing a mod to our cars, and we "think" we feel a difference. I am just as to susceptible to this. I used to have a HPP3, and swore up and down it made the car faster, but POWER wise, it did little to nothing. Now most of the companies DO make changes to the transmission programming on an automatic, which can help your cars quickness in shifting, and change your shift points. This also leads to the reports of our weak 4l60e's detonating a bit early.

So, the basic answer to the question your really asking is no, it didn't do much for you. Most people who have some experience accessing the lt1's computer will tell you that most of the program modules out there are good for recalibrating your speedo, and changing your fan on/off temps, and that's about it. Sadly, this isn't because they aren't ABLE to significantly change your engines power (I believe on a pure stock engine Ion or MadZ28 gaurantees 14 hp??), it is just that they don't bother to do so.

Jonota

 

I didn't put it on, it was on when i bought the car. My car does shift at 6,000rpm in performance mode and regular mode, but performance mode is much harder. I could take it off an test it that way but im too lazy. I did order a Jet SCU2000 which is going to remove my speed limiter, but i could have gotten a tune fo the $58 i spent on that.

 

Or you could have bought a cable and done it yourself. Lots of people out there to help, and if you don't trust that, there's lots of people out there who will do the tune for you...

Jonota