cam

iTrader: (9)

Winter time leaves me wondering about my tune. The car runs well I cant really complain I was merely curious as to how much more I could get out of my set up. I went for a dyno tune and closely watched the entire process. Aside from clearing trouble codes the only tables the tuner adjusted were the PE values to get the air fuel dialed in. I had issues with injector duty cycle so i swapped in SVO 30's under his advice and we hooked up again another day on the street. I did not see what he did but he just loaded something in that took literally a couple minutes with the key on not running. i road tested the car with his laptop plugged in to log for fifteen minutes or so and he double checked afterwards it and said it was fine.

I'm not complaining it does run okay I'm just wondering considering what I described above is there is more I should/could do to improve the tune? I just feel like theres more there when I drive it. hard to explain but its how it feels. Maybe I'm dreaming. I know I wish i had software and a wide band to play with it I just want to see what any of you had to say about it first. Thanks

Haans249

iTrader: (24)

If the tuner did not make pulls after changing tables in the tune, and especially not adjusting the spark timing, or testing at what AFR created the most torque and most horsepower, or adjusted the MAF table, and RAF table, and several other tables that are a must then I'd say you got shafted. Not only that, but dialing in the VE table is something that is huge, and can take a long time depending on what hardware they have. So, if I were you, I wouldn't be very happy, if you don't mind, how much did you spend on the tune?

cam

iTrader: (9)

We did about 7 pulls on a dyno jet with in house O2 sniffer. HP tuners latest version. The tuners good ( came well regarded ) and the rate was standard fare from what I've seen and we got the air/fuel dialed right in but I didnt see any timing changes and certainly no VE tables. After reading quite a few posts about tuning I started to wonder. Of course this all has to come with a grain of salt I dont know if he flashed in a baseline from another tune or what? No clue really i never asked hes a great guy and i dont want to insult him I'm merely curious is all.

I know hes tuned over 100 LS1's he had files all over his laptop from other tunes. I did read in another post that a guy who was tuned the same day as me went to yet another tuning shop and RAVED about the difference so a few things have me wondering how much there is left thats for sure

edcmat-l1

iTrader: (10)

MAF scaling+PE=quick and dirty. What I mean is it takes time to plot the VE table and see just how far off it is. Its the right way to tune, but also the long way. Also there is some time involved with seeing how much timing a motor wants, maximizing it, and then backing it off to get rid of the KR that you probably just created jacking up the timing looking for HP.

cam

iTrader: (9)

That makes sense.

Being a conversion and my first modified LS1 I was flying blind when I first ran the car and having bad idle issues which is why I so desperately sought out the tune in the first place. The car would start and idle fine but as soon as you blipped the gas pedal or drove and let off it would stall every single time. Its not a huge cam by any means but i read of stalling issues and cam swaps so I figured I better get it tuned. I was about to buy the software and go at it but was at that point very ignorant of all the language necessary to facilitate a tune. Tired of working on it as I has spent so much of my winter and now it was April I booked a pro tune. In the meantime I discover that my IAT sensor is broken ( literally broken ) so I order a new one and voila my idle starts to work fine. Car seems to run pretty well now but the tune is booked for the following week so on the day off I go.

First pull on the dyno I was so lean 15-1 or thereabouts the tuner was pretty shocked. He cranked up the PE values and we did another pull. EXACT same thing. He cranked them up again and same thing. He stopped messing with it and took a half hour to review the info and check some thing online. I should note I did make my own wiring harness for this car so there were TONS of codes that needed to be cleared for all the stuff i did not use. Turns out the TPS sensor was not working after his diagnosis. Fearing a wiring problem and knowing that all my splices are buried in places not to be reached on the dyno I ordered a brand new TPS sensor just to see if that was it. I swapped it and we made another pull with the same thing. I learned at this stage when TPS reaches 60% open it calls for PE which is not happening because its not working.

At this point I figured I had botched the harness somewhere and I was rather embarrassed to be honest I knew i went over every splice many times to double check but these things happen. To try and save the day the tuner hacked the TPS values to allow PE to begin right off idle and we started to make pulls that had reasonable A/F and he made adjustments to the tables. We did another 3 pulls until he was satisfied with the A/F and he said my injectors were at 130% duty cycle and advised on some SVO 30's and that I would have to hook up with him another day to have those dialed in.

So I order some and a week later I meet up and he quickly made some adjustments and i was on my way. As I said the car seems to run fine I just feel that there is more in it when I drive it. I was supposed to get back to the dyno again for another pull and I did meet up with him at the track a couple of times where we were going to throw the wide band on it and make a couple passes but for various reasons it never happened. I'm not trying to hammer on this guy he has been very cool with me I'm only trying to find out whether or not based on my info if it sounds like my tune needs a redo. I know thats a lot of reading thanks for any who have input

Oh yeah the TPS? Turns out the damn factory harness was torn off just inside the conduit right by the TPS sensor itself and whoever had worked on it prior and merely twisted the strpped leads together and electrical tape wrapped them. My suspicion was whoever owned the car previous either blew a belt that tore them off or during serive the leads got caught in the belt and tore off. Anyways the crappy splice job they did had come apart right there at the sensor. Of course I had to tear my car all back apart again before I discover this but thats how it goes sometimes. I felt good knowing at least it wasn't my work that caused the problem

pdsq98gt

I'm sure there is more in it. Drivability wise there has to be more in it since the VE table could not have been adjusted since you had to trick it into PE all of the time to tune WOT. I wouldn't blame the tuner since it sounds like he worked around the TPS problem to get your vehicle to not run a 15:1 afr.

radkon

iTrader: (2)

Unfortunately what you got is what passes for a tune now a days. MAF + PE with maybe a little timing thrown in. A lot of "professional" tuners follow this methodology.

Now for a little good news, is there much to gain? HP wise probably not maybe a few (5~10) hp but those last couple ponies take a lot of time and effort to get. If your fueling is good the only thing to adjust is spark and to get it "perfect" takes a lot of work.

Where you WILL gain will be driveabilty, street manners and fuel mileage. My "professional" tune was the same as yours. Once I started playing with it by fully mapping the VE and MAF meticulously, I gained about 10% in MPG and driveabilty went WAY up. No issues on cold starts, throttle transitions, bucking or surging.

cam

iTrader: (9)

Makes sense again. Ya I really dont blame or have any harsh feelings towards the tuner. In fact the guy is solid I like him and hes fun to race with. I'm sure if i had my end together with the injectors and TPS things would have gone differently.

Mine is BRUTAL it coughs and spits and stalls when its cold. So bad you cant drive it until it idles for five minutes or so. The car is parked for the winter now. In the warm weather its not bad but this fall it got worse and worse as the outdoor temps dropped.

Eurospec2

iTrader: (2)

No offense but that right there shoud NOT be happening, and honestly it really sounds like you got shafted. Get it re-tuned by someone else who knows what they are doing and i think you will be pleasently surprised.

radkon

iTrader: (2)

Sounds like you are still running closed loop (with the O2 sensors controlling fuel trims). Once the O2's are warm they start adjusting the AFR.

The idle issues can be adjusted pretty easily. First thing get the VE table right, its a good mathematical model of the airflow of the engine. Once that is set work on the idle and you'll be golden.

Tuners have a tough time working on cold starts because you only get one chance every few hours.

cam

iTrader: (9)

Sounds sensible. Whats the difference between closed loop and open loop? Why is mine not opening?

radkon

iTrader: (2)

Once the O2 sensors are warm, closed loop uses the O2 sensors for fueling adjustments (short term and long term trims).

Open loop relies on a "perfect" VE table (and sometimes MAF table) and ignore's the O2s.

svtwhat?

iTrader: (17)

is the time in your sig current? i would think youd have more than a few mph over stock 4th gen fbodies. My SS trapped 109 consistently, and i think it had a couple more mph in it. plus you see people getting those cars to trap 111 or so on here all of the time.

cam

iTrader: (9)

Thanks Radkon

Yeah thats my best of the season in my sig. I had bad luck getting a good pass together at the track this year. My best trap was 117 or 119 I cant recall for certain right now so theres more in it but I just cant get all the elements together at once. On the high MPH passes I had weak 60' times. When I managed strong 60's the last trips down it was blistering hot the one day and the last time down I only got two runs all day there was so many breakages in front of me. The first pass the tree guy screwed up so I didnt get a slip. The second pass I was sitting for almost five hours before the run and my trans was so cold I could barely shift the thing hence the low trap otherwise i'm sure i was 11 second bound. I didn't put down a ton of power on the dyno either but I had valve float issues so it peaked at 5200 RPM with 373 rwhp. Pretty low for my mods being an M6 and all. The car is pretty heavy though its fully jammed A/C, stereo, Glass T roofs and all I put dry weight at 3400 lbs although I haven't weighed it since the LS1 swap. With the sbc and t56 in it before it weighted 3520 so I figure I dropped about a 100 pounds off with the LS1.