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  • Tuning a 93 3.4 Firebird

    Hello everyone

    I have been reading over the threads in this section and have decided this board is an appropriate one to bring my project to considering the vast knowledge of the board members on obd 1 tuning. I'll start off by introducing myself and my car. My name is Max, and I live in the Buffalo region of Western New York. My car is a 93 Firebird with the 3.4 v6. Some of you may know that the PCM that came in these cars were sort of a mix between obd1 and obd 2 (from 93-95) and there is little to no tuning available since it is a "flash only" PCM and noone really wants to hack it. Aside from using a stand alone system that is like Megasquirt which I think can get a bit too involved. A fellow from South Florida ( I think he is a member on this board but i'm not sure) has created a tuning solution for me. He's taken a PCM from a 91 Lumina (7727 IIRC) and repinned it so that it will plug into my current PCM harness and run the car as is. The only difference is that now i can tune it because the 7727 pcm has the removable prom chip that can be tuned.

    I'm not just tuning for no reason. In fact, as of right now my car won't even drive. I've got many things done to the car. Practically all bolt ons imaginable plus P&P head work and a ridiculously radical custom camshaft from Comp. Add in bigger injectors (19lb as opposed to the stock 17) and you can start to see why my PCM is NOT happy right now. The car will fire right up and idle but it will stall out if i try to drive. The vacuum is so low right now that the MAP sensor is throwing a code even though it is working perfectly fine. I digress...

    I'm relatively new (actually completely new) to tuning, though i've been reading up on this site and others. I went ahead and bought all the equipment i will need for tuning/datalogging such as the burn 2, usb datalogging cable etc. I will be data logging with tuner pro rt and burning with moates "flash and burn" software. The only thing i will need help on ( i hope ) will be my tables. This is where you guys come in. If i datalog and put up some info, i'm hoping you will all be willing to help me with my project, or at least give me advice and push me in the right direction. Not MANY people have done this exact pcm swap with this particular car AFAIK but i've been reading up on tuning with chips and it doesn't look TOO hard.

    So can i count on you guys to help me out?

    Here's some pics to wrap up my first post.


    the car:




    the engine:




    the tuning equipment:



    the radical camshaft:





    i forgot to mention we are using the $a1 .bin, though i have been told that $8d would have been the ideal way to go because it's a "performance tune" but i don't know why it would be better if we are modifying the .bin anyways.
    Last edited by tkoforpresident; 10-27-2009, 01:57 PM.

    93 Firebird 3.4
    Pacesetter Headers, Flowmaster 80, Comp 1.6 RR,Cloyes 2x Set, P&P Heads & Intakes, Custom Cam, Holley FPR, Ram Air Intake, Posi Rear w/3.42's & Disk Brakes.
    Cam and Heads by 60Inclusive.com

  • #2
    welcome, fellow FTV6 member

    if you look hard enough you'll see where me and john(john and i? my english skills are horrbile) engineered/fixed the OBD1.5 to OBD1 conversions...
    1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
    Latest nAst1 files here!
    Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

    Comment


    • #3
      Cool. I've got a motor in my basement with a cam, 11.5:1 compression, 3500 top end, and 32lb injectors that I'll be putting in come spring time. I've got all the hardware but the burn2 as well, and will be putting together my conversion soon. I don't dare fire that on the stock OBD1.5 stuff... LOL

      Is there a newer cable for the G1 adapter to emulator now? Mine is all flat ribbon cable. I think yours looks like it's cut and made round the rest of the length like newer PC IDE cables........
      sigpic New 2010 project (click image)
      1994 3100 BERETTA. 200,000+ miles
      16.0 1/4 mile when stock. Now ???
      Original L82 Longblock
      with LA1, LX9, LX5 parts
      Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.

      Comment


      • #4
        Originally posted by robertisaar View Post
        welcome, fellow FTV6 member

        if you look hard enough you'll see where me and john(john and i? my english skills are horrbile) engineered/fixed the OBD1.5 to OBD1 conversions...
        so this is where it all began??

        93 Firebird 3.4
        Pacesetter Headers, Flowmaster 80, Comp 1.6 RR,Cloyes 2x Set, P&P Heads & Intakes, Custom Cam, Holley FPR, Ram Air Intake, Posi Rear w/3.42's & Disk Brakes.
        Cam and Heads by 60Inclusive.com

        Comment


        • #5
          Originally posted by IsaacHayes View Post
          Cool. I've got a motor in my basement with a cam, 11.5:1 compression, 3500 top end, and 32lb injectors that I'll be putting in come spring time. I've got all the hardware but the burn2 as well, and will be putting together my conversion soon. I don't dare fire that on the stock OBD1.5 stuff... LOL

          Is there a newer cable for the G1 adapter to emulator now? Mine is all flat ribbon cable. I think yours looks like it's cut and made round the rest of the length like newer PC IDE cables........

          lol yeah, the obd 1.5 pcm right now must really hate what i've done to the engine, it does NOT want to play along.

          I've got 19 lb injectors in (as opposed to the stock 17) and it runs uber rich, i can only imagine what 32lbers would do!!!

          and yes, i think all the tuning equipment i purchased is all of the "newer models" if that makes sense. (moates.net)

          93 Firebird 3.4
          Pacesetter Headers, Flowmaster 80, Comp 1.6 RR,Cloyes 2x Set, P&P Heads & Intakes, Custom Cam, Holley FPR, Ram Air Intake, Posi Rear w/3.42's & Disk Brakes.
          Cam and Heads by 60Inclusive.com

          Comment


          • #6
            Originally posted by tkoforpresident View Post
            so this is where it all began??
            oh yeah. brad(bszopi) tried doing it a long time ago and had issues, then i did it recently with no problems at all. i think john had something going around the same time as i did.

            but since I R dA CoolESt, mine got finished first...
            1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
            Latest nAst1 files here!
            Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

            Comment


            • #7
              Stock injectors on my car are 19lb, and I'm hitting 92% duty cycle right now. It's still the original 3100 but with 3400 lower, 3500 upper, 65mm TB, and 2.5" mandrel stainless exhaust. The PCM adjusted pretty well for the mods, other than it takes about 2 weeks of driving after the battery disconnect to adjust all the BLMs... LOL But I can tell just with my original modified motor I could probably pick up more power as it feels like a lot of "hills and valleys" in the powerband...

              Your car looks nice and clean. I need an air filter that big!!! LOL I think you should lower it a bit though. The rear end has major wheel gap!!! Oh and your drivers side front shock mount has a nut that is not tight...!! haha
              Last edited by IsaacHayes; 10-27-2009, 05:44 PM.
              sigpic New 2010 project (click image)
              1994 3100 BERETTA. 200,000+ miles
              16.0 1/4 mile when stock. Now ???
              Original L82 Longblock
              with LA1, LX9, LX5 parts
              Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.

              Comment


              • #8
                Originally posted by robertisaar View Post
                oh yeah. brad(bszopi) tried doing it a long time ago and had issues, then i did it recently with no problems at all. i think john had something going around the same time as i did.

                but since I R dA CoolESt, mine got finished first...
                Then i have found my Mecca


                You might be the most useful source of information then when it comes to tuning my car.

                You may be dA CoolEST but John aint no slouch either.

                93 Firebird 3.4
                Pacesetter Headers, Flowmaster 80, Comp 1.6 RR,Cloyes 2x Set, P&P Heads & Intakes, Custom Cam, Holley FPR, Ram Air Intake, Posi Rear w/3.42's & Disk Brakes.
                Cam and Heads by 60Inclusive.com

                Comment


                • #9
                  Originally posted by IsaacHayes View Post
                  Stock injectors on my car are 19lb, and I'm hitting 92% duty cycle right now. It's still the original 3100 but with 3400 lower, 3500 upper, 65mm TB, and 2.5" mandrel stainless exhaust. The PCM adjusted pretty well for the mods, other than it takes about 2 weeks of driving after the battery disconnect to adjust all the BLMs... LOL But I can tell just with my original modified motor I could probably pick up more power as it feels like a lot of "hills and valleys" in the powerband...

                  Your car looks nice and clean. I need an air filter that big!!! LOL I think you should lower it a bit though. The rear end has major wheel gap!!! Oh and your drivers side front shock mount has a nut that is not tight...!! haha
                  Well your pcm might adjust to mods, but i'm pretty sure the obd 1.5 is sedentary in that if you put in bigger injectors it doesn't really care it's just gonna run off the same old maps it did before, user be damned. Except the more mods you do, the crappier the driveability becomes and the less efficient the mods are. (where i'm at now)

                  If i can just get it running right i'll be happy.


                  I found this excerpt over at thirdgen.org in regards to tuning for bigger injectors and different fuel psi, would i be able to use this exact formula to change my BPC in the $a1 .bin that i will be modifying?





                  Ok our BPC (base pulse constant) is basically an injector constant and engine size all rolled up into one. So to calculate it we need to know a couple of things and get them in the right units and then plug it into the formula below.

                  BPC = 1461.5 * (cyl size / gm/s of fuel)

                  For cyl size you find your engine size in Liters. 350 * 16.39 = 5736.5 cc or 5.74 liters Then divide this by 8 to get your cylinder size 5.74/8 = .717L

                  For say a 65 lb/hr injectors : 65 / 3600 * 453.6 = 8.19 gm/s

                  So our formula works out to be:

                  BPC = 1461.5 * (0.717 / 8.19) = 127.95

                  So our new BPC is going to be 128. Now what happens if you don’t have stock fuel pressure? There is a formula for this as well.

                  SQRT(New PSI / OLD PSI) x (Injector lbs/hr) = New lbs/hr

                  Lets try it for 65 lb/hr injectors at 15 psi with an old pressure of 12 psi

                  SQRT(15 PSI / 12 PSI) x (65 lbs/hr) = 72.67 lbs/hr

                  So our BPC with this pressure would be 114.4 you can see how simply cranking up your fuel pressure causes big changes in fueling.




                  If i can use this equation than i can pretty much tune for my bigger injectors in a matter of minutes (or how long it takes to to figure out the equation lol)


                  btw Isaac, you don't miss anything! Oh and i'm NOT lowering the car, i don't like the lowered look.

                  93 Firebird 3.4
                  Pacesetter Headers, Flowmaster 80, Comp 1.6 RR,Cloyes 2x Set, P&P Heads & Intakes, Custom Cam, Holley FPR, Ram Air Intake, Posi Rear w/3.42's & Disk Brakes.
                  Cam and Heads by 60Inclusive.com

                  Comment


                  • #10
                    there's a MUCH easier method to determine BPC...
                    1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
                    Latest nAst1 files here!
                    Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

                    Comment


                    • #11
                      Hey Max, glad to see you migrated here

                      Robert, you may have gotten the swap done first, but how you like my cam I designed for Max? Mowahaha.
                      Links:
                      WOT-Tech.com
                      FaceBook
                      Instagram

                      Comment


                      • #12
                        Oh yeah, if you change injectors from stock everything goes out the window. My injectors are still stock. I don't have anything like a huge cam or different injectors, I know that would be impossible to drive on. But as it sets it's drivable. The new motor will be drivable but only if tuned of course.

                        What fuel pressure do you run stock? If adjusting for fuel pressure, use witchunter.com's calculator. It's more realistic as after a while higher pressure doesn't increase flow a whole lot.

                        I think A1$ is 16.7lb/hr. Opening BFUZ bin shows 224 for the BPW vs EGR at 0% EGR.
                        So for 19lb/hr injectors we take old injectors/new (16.7/19 *224) = new constant for 3.1L with 19lb/hr injectors. 196.88421 ... Now to adjust for larger displacement.

                        3.1L is 3136cc, 3.4 is 3350cc (have to use actual CC to be accurate). This time take new displacement, divided by old, times constant. (3350/3135*196.88421)=210 BPC. In TunerPro RT you can apply your adjusted value across the whole EGR table in case you want to enable EGR.

                        I don't like the slammed look either, but I like even gap around the sides and top
                        Last edited by IsaacHayes; 10-27-2009, 08:31 PM.
                        sigpic New 2010 project (click image)
                        1994 3100 BERETTA. 200,000+ miles
                        16.0 1/4 mile when stock. Now ???
                        Original L82 Longblock
                        with LA1, LX9, LX5 parts
                        Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.

                        Comment


                        • #13
                          Originally posted by ForcedFirebird View Post
                          but how you like my cam I designed for Max? Mowahaha.
                          does sound nice and wicked for a 660... but one thing it needs is


















































                          more cowbell.
                          1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
                          Latest nAst1 files here!
                          Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

                          Comment


                          • #14
                            I'll have to find my idle video and post it up of how well an OBD-1.5 PCM reacts to a aggressive cam. I still had stock injectors, though...
                            -Brad-
                            89 Mustang : Future 60V6 Power
                            sigpic
                            Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

                            Comment


                            • #15
                              Originally posted by robertisaar View Post
                              there's a MUCH easier method to determine BPC...
                              Care to share ??

                              93 Firebird 3.4
                              Pacesetter Headers, Flowmaster 80, Comp 1.6 RR,Cloyes 2x Set, P&P Heads & Intakes, Custom Cam, Holley FPR, Ram Air Intake, Posi Rear w/3.42's & Disk Brakes.
                              Cam and Heads by 60Inclusive.com

                              Comment

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