gmtuners.com

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Posts posted by gmtuners.com


  1. <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Just the Northstar engine and trans = big bucks

    4.9 engine and tran = about 600-1000

    </div></div>

    Not to bash either of these engines but people who have done the Northstar swap into Fieros have experienced PCM issues because currently there is NO tuning out for them. Without the other caddy electronics present, the engine tends to operate in limp-mode so full power cannot be realized. Those who have worked around this in the Fiero community have only gotten the Northstar engines to perform on the same level as a stock or near-stock 3800 Series II SC engine in the same type of vehicle.

    The 4.9 caddy engine has also been done, both fuel injected and some have even elected to go carbed. However, most I have seen have only churned out performance numbers marginally better than the stock 2.8L V6 that comes in the Fiero. Certainly not as fast as a stock Northstar or 3800IISC. There are a couple of people in the Fiero community who have managed to get custom cams made and even added turbos to the 4.9, but still the fastest ones cannot touch a highly modded 3800 Series II SC.

    For now it appears the best engine [in my opinion] (most reliable and most power potential) to use for a swap is the 3800 Series II SC. Cheaper to come by than the Northstar, and much cheaper to mod and install into a Reatta than either caddy V8, it would be my engine of choice for a swap...unless of course you can't live without the V8 sound...or horrible gas mileage that comes with it smirk.gif .


  2. <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I really think using the 94-95 L67 computer is a cleaner answer since all of the engine management and sensor values are already right and the "E" trans programming is already there

    Turns out the gentleman kept the ECC at least initially but is missing tach and coolant temp displays (and I suspect the engine is getting the wrong speedo information) and the a/c is not working properly.

    For Greg's we were able to use the 88 Computer so the data stream was right but there are still a few elements that are not right (we also learned a bit about spark advance curves and boost).

    NONE of this is impossible, it is just a matter of reprogramming the PCM the match the Reatta ALDL communications, is how it "talks" to the BCM which controls the displays. Since the Reatta has built in MPG and scan tool capability, this is a whole lot more complicated than putting a 3800 in a Fiero, that is if you want everything to work.

    This is part of the reason I am trying to build a simulator but is *very* time consuming - time which, as yet, I have not been able to find.

    However it is possible and will happen just as soon as there is enough motivation, just not yet. </div></div>

    Hello, I am the person who did the L67 swap into the Reatta featured in the webpage link provided earlier in this thread. Allow me to answer some of the questions that have come up in this thread thus far.

    The owner of this vehicle approached me a while back about doing this swap and said he wasn't too concerned if the ECC became non-functional since he had interest in upgrading to the later IPC/BCM setup that comes in the (1990?-91) Reatta's.

    I went ahead and did the swap using the 94-95 Bonneville/Riviera 3800 PCM since I have tuned many of these PCM's to work with the Series II SC engines. I also re-used the original Reatta engine computer harness and just changed connectors and added wires for the electronic trans. Yes, the IPC and ECC does still function; but as mentioned earlier, the temp and tachometer gauges don't work, nor does the fuel mileage computer function. The A/C doesn't work either because the ECC sends out an A/C request command over the serial data bus, but the 94-95 PCM's never had this function available (94-95 Riviera's used a seperate a/c request wire). I do have a plan to wire in a simple toggle switch in the ashtray or other owner preferred location as a last resort IF the PCM-serial data communications issue cannot be resolved. The speedo and odometer register correctly because these functions got a 4000ppm signal input from the original ECM (which the 94-95 PCM also supplies).

    At some point the owner intends to switch over to the newer Reatta IPC/BCM/HVAC head, etc. If at that point we could not get the 94-95 PCM to interface with these components, we could always swap in the 92-93 3800SC PCM which will work with the 4T60-E trans and the (90?-91) Reatta IPC/BCM/HVAC, etc. The only difference would be the EGR valve type. Worse case scenario, I could have an adapter plate made at a machine shop so the early 3-solenoid EGR could be used on the Series 2 engine.

    Until we get to that point, I am still doing research to see if anything can be done with the 94-95 PCM to get it to communicate with the earlier Reatta electronics. I have emailed <span style="font-weight: bold">padgett</span> all the info I have on ECM/PCM serial data message schedulers and perhaps something can be found. But as of right now, the owner is enjoying his new-found power and the 94-95 PCM's serial data line is NOT connected to the Reatta (otherwise the IPC and ECC will flip out because of a miscommunication error).

    I would be happy to answer any questions about this swap any of you may have.

    -Ryan G.