looking for a multiport intake to swap onto my TBI vortec head 350, EGR is a plus!
looking for a multiport intake to swap onto my TBI vortec head 350, EGR is a plus!
Do you have any experience with that setup? I'm curious how they perform and how tunable they are, and would it be better to run it off the stock pcm since it controls my trans. May be an option if the performance is good and reliable. I would have to get a bootleg inspection since we have visual under hood here just for egr and such, I have a dummy EGR bolted up on my performer RPM airgap now that gets me through inspection. I started reading the thread on using an L31 intake with TBI PCM since I have one already but didn't seem like that ended very good.
Tuning the TBI PCM with a Wide Band O2 Sensor (WBO2) is a very good plan. My WBO2 thread: http://www.gearhead-efi.com/Fuel-Inj...g)-Spreadsheet
Usually 8 port injectors is better than 2 throttle body injectors, wet flow intake vs dry flow intake.
Edelbrock has discontinued production on the Vortec MPFI system (part # 3506) https://www.summitracing.com/parts/edl-3506
The factory L31 intake system is an option to consider, if factory L31 horsepower / torque is acceptable?
Using a WBO2, I was able to "Tune" a 1995 Tahoe with a transplanted bone stock L31 to 260 RWHP using the Tahoe TBI PCM modified for MPFI.
dave w
I had no issues with the kit- but injector drivers were were an problem for some.
That is a strong running bone stock L31. I have gotten 230-250 RWHP and 300-320 RWTQ out of them with headers and full exhaust and a very aggressive premium fuel only tune, but nothing more than that. That is running them at about 12.6:1 air/fuel ratio and 30-32* of timing advance. That amount of power is what I typically see out of tuned bolt-on B-car LT1s with 1.6:1 rockers, headers, exhaust, and an aftermarket air intake.
7747 ecu, this is what Howell told me at one time. With the EBL/7747 there is a schematic that shows injector wiring being tied together (from memory) which I did not do and have had no problems.
At the time with vortec heads on a standard block, poor tune, 255 hp to the wheels in a 4x4 auto. Cannot remember cam.
Last edited by dfarr67; 04-03-2019 at 12:00 AM.
On the topic of injectors and injector drivers. It can be very challenging, when a tuner does not fully understand the differences between a peak-n-hold vs. saturated injectors. With a good electronics understanding, a tuner can effectively use peak-n-hold injector drivers to effectively operate saturated injectors.
It's very common for an EFI project to be low in cost, and provides better than stock performance. The 1227747 is low cost, the 16197427 is low cost. Sometimes the cost of the EBL system is more $$$ than the entire budget for the EFI project. Sometimes a low cost EFI project combined with a poor understanding of injector types, injector driver electronics, and the injector parameter programming in the chip will lead to the conclusion "injector drivers were were an problem for some"?
dave w
Those Edelbrock systems are quite old I think, techniques always change. If I were to do it again the 7747 wouldn't fly, either the 7427 or 0411 even for just the electronic trans control. The impression I got on the drivers is that they were overloaded and damaged. I was having problems with solder joints from the TBI injector harness to Edelbrock MPI harness- Howell refused to put an injector harness together for me.
I bought that MPFI kit brand new at the time- expected it to be a little more solid- you say quality of tune and I remember the literature saying for vortec crate engine only.
Perhaps the following statements apply?
The more you know about EFI, the less you pay for EFI.
The more you know about EFI, your ride will get up and go better with EFI.
dave w
I haven't had much luck so for on finding an alternate mpi intake for vortec heads within budget plus the EGR issue, I do have a stock L31 intake that I could upgrade with the mpi injector spider and maybe an intake spacer plate, not sure how much they help? Would this work with my 6395 PCM?
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