Question about MAF vs. speed density EFI in EB...

[Barabbas]

For years I've been reading forum debates on MAF over SD in the 5.0 conversions. I live in the foothills of the Rockies at 5000' and every time I take my rig out I go to at least 9000', often 10K+. I don't make it down to see level often, but I'd like to be able to without having issues. My question is can the SD setup be calibrated to roll with these changes in altitude and temperature (sub-zero to 100+), or will this require MAF? Why? Every topic I've read on the subject seems to reference further mods, as if HP was the goal. Who can say HP is a BAD thing, right? But this is not a Mustang. I'm not going to the drag strip or even a strret race! I'm shooting for a solid 300 horse, but torque and drivability are my main objective. At this stage of my build I have:

73 Bronco

Built 302W block out of late 60s Mustang, 11:1, mild cam, installed EFI out of 88 T-Bird (speed density unit with white (I believe 17#) injectors), mated to a new NV-3550, and (not that it's really relevant, but... )rebuilt DANA 20 w twin stick, D44 front w discs, BB9" rear, 4:11 gears on 33's. Once built, I have no plans for further mods to the engine or drivetrain. Just wanna drive it! I'm not building a "rock crawler", but a daily driver I can take camping/fishing and mudding, jeep trails etc. Go around the rock for God's sake!

I plan to purchase an A9P ECU, harness and 19# injectors. My understanding is that you can run the A9P (for auto trans) with the manual trans, but not the other way around. Reason: I've also heard the A9P features more aggressive programming than the A9L to compensate for the sluggish AOD. If this is inaccurate, please correct me. Before I start that whole thing, I need to determine if I'm going MAF or sticking w the SD setup, as I will need an 89 or later ECU and a MAF setup, diff harness etc... Basically, I don't have $$$ to burn on MAF if I don't need it, but will not hesitate if required for ultimate drivability in my environment. BTW: Does anyone know a good tuner in N. CO?

Also, if there are any obvious oversights or potential issues w my current setup or plans (A9P + 19#), I'd like to hear about it. Thanks for your feedback!

 

[astronot]

Wow! This was all Greek to me until I found this:

http://www.pcmforless.com/index.php?option=com_content&view=article&id=126:speed-density-sd-vs-mass-air-flow-maf-&catid=34:tuning&Itemid=56

I'm pretty sure the answer to your question will not be here, but at least some folks like me who are not up to speed on the topic can get a quick education.

 

[Barabbas]

Funny, I had just read that one before posting here, ands it's one of the better one's I've come across. My question is really specific to the constant changes in altitude/temperature around here as they both affect air density. Thanks for taking the time to reply.

 

[mikeiam82]

im pretty sure the speed density setup cant be reprogrammed to change air fuel mixture because its set on pre-determined air fuel based on speed of the engine. The only way i know how is to use the mass air setup for the constant readings. According to my brother all you need to do to switch to mass air from speed density is to get a computer and a wiring harness with a mass air sensor or buy a premade harness form 1 of the bronco sites for plug and play. those run $500 tho.

 

[Barabbas]

Mike,

It seems we have a similar build going. I've seen those $500 harnesses from the Bronco Parts retailers. Kind of crazy if you ask me. My plan was to build my own from a used 5.0 harness. Figured if I had to replace every connector I couldn't spend half of that... until I discovered the stage II MAF conversion from fiveology ($400) with the 73 mm MAF housing. Pretty complete kit.

http://shop.fiveologyracing.com/Stage-2-Mustang-Mass-Air-Conversion-MAF73M.htm

Because my motor is mildly modified, I'll probably switch up to the 24# injectors with this setup. I'll overshoot my HP mark a little... but things could be worse, right?

 

[mikeiam82]

ya, i got a stock speed density 88 mustang engine with everything i need to make it work including the harness from a mechanic friend of my local snap on dealer. Im pretty sure all you need to do to make it work is hook up the hot/switched/ground wires and it will run, unfortunately im not at that stage yet so i cant say if it is easy of not. I just got my engine and transmission mounted in the frame and my body is still in pieces outside.

That kit looks pretty good for those looking to make their engine MAF by upgrading their SD harness on a budget. 1 plus to the $500 harness is you can add rollover switch egr bypass switch and a couple other options but for those not rock crawling that stuff doesnt matter and we dont exactly have check engine lights on the dash. plus on top of the cost of the harness you need to buy the actual maf sensor and computer. Your kit gives you everything needed if you cant find the parts at a junker. ill have to consider this option if i cant find what i need for maf at the junkyard 5 mins from my house.

the bcbroncos.com website has a lot of info regarding efi conversions if you look.