very sorry for my ignorance,

how can i tell if i have mass air or speed density?

i have a 96 F250 351 EFI HD - just got ZF 5 speed rebuilt , just got engine bored out... (had to double clutch from 2nd to 3rd and couldnt gear down from 3rd to 2nd under normal rpms, one of my cylinders was screwed and i had to get new plugs, etc., etc., every 6 weeks), i got opportunity to get everything fixed (i didnt have to pay)..

anyways, i just got it back a couple days ago so i'm taking it pretty easy, but it doesnt seem the same.. the mechanic said my engine was dusted and was saying that there was a gap between the k&n filter and the case, he said that could have been why so he tried some other brand of filter, another gap (he said), so he put in the stock filter and i have the k&n behind my seat... could this cause that much of a (what seems like) decrease in performance?.. also he said he would put on a better cam than normal.. i said go for it (i didnt have to pay) at 1st he was talking about RV cam, but later was saying it's the same as whats in a mustang (i think)... could that cause decrease in performance? i also have headers and roller rockers in it (had them before)...

i was going to next put in dual flowmaster 40's, but now i'm thinking i should check into this mass air conversion (if i 'm on speed density)

thanks a bizzillion, truly appreciated

 

look at the airbox and the line that runs from the airbox to the intake should have a round metal "Meter" with an electrical line running to the wiring harness. This is mass air

Non mass air will not have the "Meter".

 

thanks a lot for the reply brett_d... i was kinda hoping you would reply (i think it was you who just went thru a mass air conversion)[??] i've been searching thru the archives..

well, nope, i'm a speed density lame-oh..

any advice? i'm not at all a mechanic.. i know tools, i can weld, i've got a good knack for common scence (i think anyways).. (i'm not an idiot!).. i've just been trying to learn the most about my truck that i can, and have been trying to get the best out of it, for what i can afford and/or can accomidate for...

when i 1st bought it (really cheap, fairly beat on) all i cared about was that it had the body style i was after (i want to keep this body style) and that it was 4x4, 351, 5 speed, zf tanny, and good to go...

i (obviously) should've learned more about it before getting work done to it, but i didn't.. i took it in and asked what were the best opts i could do for decent money... i had headers, roller rockers and k&n filter installed...

now i wanna buy a mass air conversion (kit?) and install it myself..

if you can make any suggestions i'd be very gratefull..

thanks... a lot

 

I know that some people are having problems locating a mass air conversion for the 351 manual transmissions. For some reason they do not make them. I have heard of some people buying the 302 one and using it on the 351. I'm not quite sure if it matters or not since the firing order is different between the two. Other than that you just need to make sure the meter is calibrated for the pound rate of your injectors.

As far as installing the kit it isn't that hard to do. It took me around 5 hours (at a slow pace) to do it. The hardest thing to do is to install the overlay harness. The conversion kit will give you a overlay harness that will replace the harness connection at each injecter. So to do this you will need to remove the upper intake manifold. It's not hard just a pain.

Just make sure you don't drop anything into the lower intake when the upper is removed. Other than that all you have to do is replace the computer (pretty easy), cut the intake hoses and install the "Y" adapter (EASY), and install the mass air meter and the airbox lid (also easy).

It is a pretty simple job to do as long as you take your time and don't rush anything..

Haste makes Waste!

 

Where can I get a MA kit for my '91 F-150 with 302/auto, and what improvements can I expect? How much $ will it cost?

What brands of kit are available?

Thanks,
-Mike

 

I got mine from summit. I decided to get the Ford Motorsport one because it was about the same price of the other brands and it was made by Ford (so it must be good right!). I paid about 650 I think for mine. Either you can pay the buck for the kit or scrap together the parts on your own. I was told you can buy the overlay harness from painless wiring but I am not sure. Other than the harness the rest is easy.

1. You need a computer from a mass air controlled mustang or equivelent ( I believe the computer I got with the kit was from a 94 mustang 5.0)

2. Y adapter to convert the intake hoses into one hose (can be made by a muffler shop)

3. Mass air meter that is calibrated to the poundage of your injectors. ( can be bought just about anywhere)

4. You will have to make some type of plug to fit in the old wiring harness to plug the old fuel injection leads (Maybe you can get this from Ford, I have no idea)

5. A filter that will fit the mass air meter that you buy (usually the mass air meters are 3.5" so you can get a cone filter from s&b filters that is 3.5"x12", the bigger the better right!)

Good luck on whatever you decide!

 

[updated:LAST EDITED ON 23-Feb-02 AT 03:07 AM (EST)]hey brett, mass air kits cost $bux!
but, from what the guy from proflow says i need, i gather i can get the parts for less $$.. but i need to know i'm getting the right parts!
he says i would need:

a computer from a 89-93 mustang (5L 302 i gather).. junk yard or ebay = cheap (says a computer from a auto or manual will work because i have a manual, but if i had a auto i would need one from an auto)

a harness which is cheap, but do i need a particular harness? (5L 302 work? from a mustang or F150?)

O2 sensor bungs (any particular O2 sensors? or i could just buy them new for 50 bux)

a 75mm mass air meter which is a couple bux but aslong as i can get any good 75mm meter calibrated for my injectors i assume it will work...

and ofcoarse, the Y pipe, filter, mounting hardware, etc..

i think i have 19lb injectors, but i'm not positive..

anything i need to know?

thanks

96 F250 HD 4X4, 351 recently bored .020, ZF 5 speed recently rebuilt, 10.25 rear, Dana 50 TTB IFS front.. blah, 3.55 gears, 285/75 R16 BFG A/T, flowtech headers, crane cam.. lift: intake=.485 exhaust=.522, duration: intake=200 exhaust=206, crane roller rockers, K&N FIPK, speed density.. blah!

any and all help muchly appreciated

 

I am not sure that the 89 mustangs were mass air. I dont think they were but I am not sure. You just need to make sure that the mustang you get it from is mass air is all ( and of course it is for a 5.0 not a 4.6L)

You can buy a overlay harness which actually does not replace your current harness it just "Overlays" or lays underneath the stock one. I know that you can buy this somewhere for a decent price but I can't tell you where. Check the search engine on this site I remember someone talking about this earlier.

I don't know why they are suggesting o2 sensors. That didn't come with my kit. So.....

The size of the Mass air meter will not matter as long as it is calibrated to your injectors....

Other than that, I can't think of anything else besides the cone filter that you will need!

 

are you planning on doing extensive mods to youe engine i.e. camshaft, heads etc? if not there is no need for you to buy mass air. and putting mass air on a near stock engine will net you no performance gains. it simply makes it easier to modify your engine and keep it driveable and able to idle. if your plans only reach as far as exhaust, air filters, etc then your $1000 would be better spent elswhere. there is no need to install mass air unless idle engine vacuum is changed or radical engine mods are made such as performance cams etc.

 

[updated:LAST EDITED ON 23-Feb-02 AT 09:25 AM (EST)]>
>well, nope, i'm a speed density lame-oh..
>

>
>i too am a "speed density lame-oh" who is making cloes to 450hp without mass air. i just dont want to see anyone waste their money if they dont have to. mass air is a big chunk of change. people should read and understand more about MAF before they go and spend a grand on it. just understand how it works and why you would need it and then decide if you need it for your application. people read magazines and see MASS AIR. all performance sites on the net have MASS AIR plastered all over them. so people see this and think they need it to mod the truck. i guarantee you that half the people on this board who purchased mass air dont even need it!
:-X11

 

thanks for the replys all...

well, since getting a new cam (more lift than stock) i havnt noticed any difference really, and i assume it is because speed density wont allow for any noticable performance gains > as far as vacuum is concerned... i figure if i can buy all the parts (part by part) for good prices, eventually i can convert to mass air without having to spend 1000 all at once.. or all together for that matter..

just an idea...

thanks again

 

its not the lift of the cam that determines idle vacuum. its the lobe separation and overlap. usually cams with lobe centerline angles below 112* start to give a choppy idle and vacuum is poor. speed density is based on the map sensor and the map reads vacuum to determine engine load. so when a lopey cam is installed and idle vacuum is poor the map thinks the engine is under a load and in turn delivers fuel to the cylinders. this is the reason that the engine wont idle and driveablilty problems become present due to a overly rich condition. and if your running the STOCK heads with a decent size cam then this is why you have not noticed a performance gain from that cam swap. it is not because of the speed density. you cannot take advantage of the higher lift because the heads dont flow well. the stock heads dont flow for #####. especially the exhaust ports. if you installed a decent flowing set of heads to take advantage of the performance cam you would get the seat of the pants feeling youre looking for.

 

For the same 1000 or so you can have a completely programable speed desnisty system that will handle any mod or amout of turbo or supercharger boost you care to use.
Plus you have control of spark curve.
You also don't have a fragile expensive AFM that will get fried the first time you over oil your K&N filter.

Check out simple digital systems for speed density that will handle any mod.

 

BINGO!

 

you guys rock

thanks a lot, i love learning

so, new heads and larger diameter headers?

any recommendations?

thanks again.