Bronco Forum - Full Size Ford Bronco Forum banner

1 - 20 of 23 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter #1
Sorry for not being able to take the time to search the forum on this one. Has anyone done the conversion from the Speed Density EFI to Mass Air Flow EFI on thier FSB with a 302?? I am replacing the engine with a rebuild and am just now finding out I'm not going to gain anything and could possibly ruin this engine with the SD EFI. I am not the most technical savy guy, so, if it's relatively easy, I can do it but not if it's complicated. I have limited time and money.

Would it just be easier to scrap the EFI altogether and go to carb setup?

Thanks for the help.
 

·
Heavy and slow fun
Joined
·
1,152 Posts
There is many threads on this subject. You really need to research this before you start. It is pretty easy i think.I have done it twice. Do you have to H.O. firing order? What tranny do you have? Do you want to go with sequential or bank fired? Truck intake or car intake? Many variables.
 

·
RBV Abuser, F/S user
Joined
·
747 Posts
Yeah. Who told you that you would ruin the engine and HOW?
 

·
Registered
Joined
·
453 Posts
you will not ruin a motor with SD. alot of people swear by it. Others perfer the mass air system. I am looking to swich to mass air also. If you have an electronic trans like the e40d then you have to use an ecm or a seperate trans controler like the bauman tc (there are others out there) and then run the mass air seperate like from a mustang (A9L) computer just to manage the engine side .if you dont have the electronicly controled trans you can just run the stand alone mass air system like the mustang.
 

·
Registered
Joined
·
9,895 Posts
I switched a 96 mass air motor to SD 5 years ago and it's going strong..
 

·
Registered
Joined
·
27 Posts
Discussion Starter #7
The trans is an AOD so I don't have to worry about that part. I read on a web site that talks about the conversion that trying to mod with SD EFI can cause the engine to run hot and erratic (spelling?). This in my mind would eventualy ruin the engine. I'll see if I can find the site again.
 

·
Registered
Joined
·
9,895 Posts
Stock.. But a built one would be the same.. The SD ECU is going to control it like a SD engine..

I do plan on going to a mass air setup in the future.. I bought a 96 ODB II motor and put it in the 87.. Unfortunately the ODB II would really work in the 87 without a big huge headache so I just went to ODB-I
 

·
The Anti Yam!
Joined
·
22,680 Posts
I read on a web site that talks about the conversion that trying to mod with SD EFI can cause the engine to run hot and erratic (spelling?). This in my mind would eventualy ruin the engine. I'll see if I can find the site again.
Poppycock!

SD works fine with almost any mod.

But it has two important limitations that it can not overcome.

1. It needs a cam with a lobe separation angle of 114* or more. Some have gotten by with 112*, but most have problems any time they try and use stock SD with less than a 114* LSA.

2. Stock S.D. runs 19lb hour injectors, that is the limit to how much fuel can be suplied to the engine. Go beyond that limit, and you will run lean. However, the exact same 19lb/hr limit exist on Mass-Air. To run either with larger injectors requires a tuner/chip
 

·
Satyr of the Midwest
Joined
·
17,736 Posts
Don't bother unless you're doing serious modifications. . . or you're just nuts like me. . . . :toothless
 

·
Ex Navy Nuke
Joined
·
5,421 Posts
Keep the SD, whoever said it could ruin the engine has no idea what they're talking about. The factory put it in and it ran fine for decades.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #13
I love a good heated discussion. The engine was built up a bit and that was my main concern with the SD EFI being programed to a specific set of numbers and conditions.

Now for the good news! Problem solved! The guy I bought the engine from that did the re build called me today after looking into it and found that the engine he sold me won't work at all. Too much of the wrong stuff. He has offered to take his engine back and mine as well and he will re build mine to the proper specs for SD EFI. This will eliminate all of the problems I was having to overcome with the AIR system, some of the sensors and the SD EFI. There were also incompatibilities with the flex plate and harmonic balancer and the water pump. All of them solved by rebuilding my engine.

I am pleased as punch and can sleep at night now.

Thanks a bunch to all who tried to help me. This has been one hell of an education for me. Next time I have to do any work like this I will do all of my research first instead of chasing down information after spending the money.

Thanks again to all and have a great weekend.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #14
I'll keep you all posted. Should be about 3 weeks to get it back.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #15
Poppycock!

SD works fine with almost any mod.

But it has two important limitations that it can not overcome.

1. It needs a cam with a lobe separation angle of 114* or more. Some have gotten by with 112*, but most have problems any time they try and use stock SD with less than a 114* LSA.

2. Stock S.D. runs 19lb hour injectors, that is the limit to how much fuel can be suplied to the engine. Go beyond that limit, and you will run lean. However, the exact same 19lb/hr limit exist on Mass-Air. To run either with larger injectors requires a tuner/chip
Gacknar, Do you think that mildly beefing up my 302 with a .030 over bore and a mildly hopped up cam will exceed those injector capacities? It sounds like a mild beefing up won't hurt anything. What do you think?
 

·
Registered
Joined
·
408 Posts
Running a mildly modded engine on SD won't hurt anything, but you won't be getting the most out of it. The fuel trims will be a little off at different RPM's, and sometimes under heavy load at a low RPM, it'll be really off.

Running MAF with a mildly moded motor (headers, intake, good exhaust, very mild cam) will be a lot closer, but still not perfect. The MAF ECM can adjust for a lot more, but still not everything. Most people that bring in their good running, mildly modded engine will get about 10-20HP and a much better torque curve. This comes from the right amount of fuel and timing at the right time.

If you want the most from your motor, run MAF and get a tune done on a dynojet. If you can settle he get a MAF or SD setup. MAF will be slightly better from a power and fuel mileage point of view though.
 

·
The Anti Yam!
Joined
·
22,680 Posts
Gacknar, Do you think that mildly beefing up my 302 with a .030 over bore and a mildly hopped up cam will exceed those injector capacities?
Absolutely not.

But you'll be better off saving money on the cam and spending it on heads.

And remember, any cam you use must have 114* (Or more) of LSA for S.D. to be happy with it.

Running a mildly modded engine on SD won't hurt anything, but you won't be getting the most out of it. The fuel trims will be a little off at different RPM's, and sometimes under heavy load at a low RPM, it'll be really off.
Balderdash
 

·
Registered
Joined
·
1,639 Posts
Gacknar, Do you think that mildly beefing up my 302 with a .030 over bore and a mildly hopped up cam will exceed those injector capacities? It sounds like a mild beefing up won't hurt anything. What do you think?
I'm not gacknar , but that setup is what I have in my FSB87 and it runs great with Gt40 heads, explorer intake and 3" exhaust all on SD EFI.

I did loose some bottom end torque tho
 

·
Satyr of the Midwest
Joined
·
17,736 Posts
Some peoples' version of "runs good" is really, really F'ed up, IME. I've had people try to sell me vehicles with two dead cylinders they thought "ran great".
 

·
Registered
Joined
·
408 Posts
Absolutely not.

But you'll be better off saving money on the cam and spending it on heads.

And remember, any cam you use must have 114* (Or more) of LSA for S.D. to be happy with it.

Balderdash
SD motors already notoriously run rich, confuse the computer a little more with a lot more airflow at a lower rpm and it will overcompensate for the lean condition that creates, making it uber-rich.

If you change to MAF you will see a better torque curve and 10-20HP. Hell, this was even on trucks back when stacy david was on it! On the dynojet any everything.
 
1 - 20 of 23 Posts
Top