I have a 90 5.0 with mildly built heads, ported and valve job, intake and f303 with 1.7 rockers. Would going to the 80 MM pro m mass air be too much to put on that motor matched to 30 lb injectors?? If so what mass air would be better and keep in mind Im talking with price not being a factor. Now with price being a factor which mass air should I go to?? I am also going to purchase a 70 mm accufab tb to go with it.
Is the 80 mm Pro-m mass air too big??
- Thread starter stangandy
- Start date
HO93LX302
Founding Member
Do you have any plans in the future of putting better heads, or maybe a blower?? 80mm is kinda big but i'd say go with it so you won't have to get it down the road sometime.. just buy it once ya know... the 70mm TB should be fine.. I have the BBK 70mm on my stock long block 302, but i had it on because i had a blower on my motor, then i sold it
powershift351
New Member
80mm pro-m plastic and 70mm accufab w/30's. Perfect for your set-up.
Last time I checked the 80mm pro-m was $199. What intake and exhaust do you have?
Last time I checked the 80mm pro-m was $199. What intake and exhaust do you have?
04sleeper
Founding Member
I have an 80 mm Pro-M and it is definatley not too big. My motor is mostly stock but puts out good power for what it has. The 30's are a little big for you combo though unless you are going to be planning on adding some more mods later.
bluevenom867
I will have images of molesting stuffed animals in
When you have fuel injectors with a rating much higher than you need, they pump fuel into your combustion chamber in a lazy manner and you get poor fuel atomization. This, likewise with exhausts, is another scenario where too much or too big is bad. I say downgrade it a bit to 24 pounders, they work well for mild to above averagely modified. Unless you're pushing the nearly 350 horses range without a doubt, 30's just aren't for you at the moment.
cobrabuilder
New Member
Michael Yount
Mustang Master
A 75mm maf and 24# injectors are more than sufficient for your motor. There's no performance benefit to running either a larger maf or injector. The larger maf won't hurt anything. The larger the injector is the more of a challenge it may have metering very small amounts of fuel - like at idle or very low load conditions. A good rule of thumb is to run the smallest injector that will meet your engine's needs. It's possible that you could actually get by with 19's looking at your sig - but the 24's will give you a bit of room for growth. I wouldn't put 30's in it if it were mine. The maf should be calibrated for whatever size injector you run - and the fuel pressure should be set where the ecu expects it to be - at the stock setting 38-40 psi with the vacuum hose off.
What I meant by mildly built is a set of high port heads stage 2 ported and a 3 angle valve job. I also had my holley intake ported sufficiently to the heads. I want a setup of injectors and mass air so that I wont overkill my motor with my combo, but will be able to put on a dry nitrous kit until I put my turbos on. I was the idiot that tried putting on 42 lb injectors with a blowthru univer mass air and let me tell you it was not a smart decision. I have had my heads cam intake build up down for about a month and a half and I just want to get the darn thing runnin. DO you think a 75 mm mass air and 24 #'s would restrict what I want to do or is a a better combo.
04sleeper
Founding Member
The 80 mm plastic Pro-M is the best by far!!!!! 
I'm not sure where you got the info about the power rating but don't believe it. The 80 mm will give you the best power increase and the drivability will be much better with the 80. It is the most versatile meter on the market. You can't go wrong with it.
I'm not sure where you got the info about the power rating but don't believe it. The 80 mm will give you the best power increase and the drivability will be much better with the 80. It is the most versatile meter on the market. You can't go wrong with it.
BlackFox5.0
Founding Member
I think the 80mm is perfect for a blower car, but on anything else where your not making insane amounts of power I don't think it's worth the extra money.
04sleeper
Founding Member
The Pro-M 80 is designed much better than the 75 mm Bullet. You will have better driveability with the 80mm. Thats woth it in my opinion.
Michael Yount
Mustang Master
Well, Andy, we get the REST of the story. If you'd told all of us up front you were gonna be adding turbo(s) later, we might have steered you in a different direction. Yes, the 80 will be fine. If you're trying to match up injectors now that will feed the turbo engine, then you probably need at least the 30's, maybe 36's. Go to www.pro-flow.com and open the meter sizing tab, scroll down -- it will provide some guidance for you in the area of injector size vs. HP in a boosted application.
Hehe Im sorry guys I really appreciate the help. Problem is that I have been having a friend tell me things and now nothing works right so I have decided to go to you guys. I am going to get 30 lb injectors with the 80 mm mass air for this combo:
high port heads, holley intake, f303 w/1.7 rockers. Maybe plans on putting on a dry nitrous kit. If this sounds bad then please tell me before I get em, if no responses then good deal!
I already have 42 lb injectors with the univer mass air calibrated for them, for my turbos. Im just trying to get the naturally aspirated with maybe somie nitrous later to work! Thanks a bunch for your guys' help!!!
high port heads, holley intake, f303 w/1.7 rockers. Maybe plans on putting on a dry nitrous kit. If this sounds bad then please tell me before I get em, if no responses then good deal!
I already have 42 lb injectors with the univer mass air calibrated for them, for my turbos. Im just trying to get the naturally aspirated with maybe somie nitrous later to work! Thanks a bunch for your guys' help!!!
Yeah that would have really helped. If that's the case then here's what I would reccomend - don't worry about the fuel injector size and the MAF calibrated for those injectors until you get to that stage where you are slapping that turbo and nitrous kit on there and get everything else straight first. Then pick the size you need after you are happy with the final combo you decide to go withMichael Yount said:
86Cobra
Founding Member
As has already been said, the Pro-M 80mm is a much better meter than the 75mm Bullet. 30s will be absolutely fine for that motor. All the "problems" caused by larger injectors are 95% internet myth. Larger injectors *can* cause an idle surge IF you use a crappy meter. Run a Pro-M 80 and you'll be fine.
If you already have the meter, then use it. But, if you feel that a 75 is a better fit then your 80, i will trade ya. Mine is for 30s. i wanted to pick up a 80mm anyway. PM if you wanna trade.
Michael Yount
Mustang Master
"All the "problems" caused by larger injectors are 95% internet myth. Larger injectors *can* cause an idle surge IF you use a crappy meter. Run a Pro-M 80 and you'll be fine"
86Cobra - I think you may have oversimplified here - unintended I'm sure. It's not just crappy-meter syndrome. The question is how well/accurately has the meter calibration been done to match the endusers set up. People buy/trade/sell meters as if they are a simple plug and play operation. That's simply not the case. When ProM sets one up, they do so with regard to a number of variables - naturally aspirated or not, displacement, ecu type, intake air configuration, filter type and placement, injector size, etc. When they're matched up properly, no doubt, an 80mm ProM and 30# injectors will probably work just fine. And when the turbos go on, likely the injector size will increase -- and the meter will need to go back for the new configuration and transfer curve. I've got a buddy locally that's chasing drivability and detonation issues that we think are likely maf related. He has a used Granitelli maf (Made by ProM) and 30# injectors. Is it a crappy meter? I'd say not. But what was it originally set up for? Who knows.
As to what size to get for what Andy's building now -- there's simply no benefit to installing an injector that's larger than the set up calls for. And the larger the injector is, the more difficult metering small amounts of fuel accurately with it is. On the new GT (if I'm remembering correctly) Ford has two smaller injectors for each cylinder instead of one big one. The reason? They can control idle quality/speed/emissions, and part throttle drivability much more precisely with a smaller injector than with a larger one -- their reason, not mine. That's not internet myth. Could they have tuned their way around it? Perhaps - but they ultimately decided metering small amounts of fuel was more easily and accurately done with a smaller injector.
Now, will going with 30's in this case instead of 24's cause idle or low rpm problems? Probably not if the meter is calibrated correctly and has the right transfer curve - I think that's what you were alluding to. Does the engine with the set up described need 30's? No, 24's are more than sufficient. What will happen when turbo(s) go on? I think larger injectors will be needed, the maf will need to be reworked - not just for larger injectors, but for an entirely different forced aspiration set up, and a chip will likely be needed to help with the overall state of tune.
86Cobra - I think you may have oversimplified here - unintended I'm sure. It's not just crappy-meter syndrome. The question is how well/accurately has the meter calibration been done to match the endusers set up. People buy/trade/sell meters as if they are a simple plug and play operation. That's simply not the case. When ProM sets one up, they do so with regard to a number of variables - naturally aspirated or not, displacement, ecu type, intake air configuration, filter type and placement, injector size, etc. When they're matched up properly, no doubt, an 80mm ProM and 30# injectors will probably work just fine. And when the turbos go on, likely the injector size will increase -- and the meter will need to go back for the new configuration and transfer curve. I've got a buddy locally that's chasing drivability and detonation issues that we think are likely maf related. He has a used Granitelli maf (Made by ProM) and 30# injectors. Is it a crappy meter? I'd say not. But what was it originally set up for? Who knows.
As to what size to get for what Andy's building now -- there's simply no benefit to installing an injector that's larger than the set up calls for. And the larger the injector is, the more difficult metering small amounts of fuel accurately with it is. On the new GT (if I'm remembering correctly) Ford has two smaller injectors for each cylinder instead of one big one. The reason? They can control idle quality/speed/emissions, and part throttle drivability much more precisely with a smaller injector than with a larger one -- their reason, not mine. That's not internet myth. Could they have tuned their way around it? Perhaps - but they ultimately decided metering small amounts of fuel was more easily and accurately done with a smaller injector.
Now, will going with 30's in this case instead of 24's cause idle or low rpm problems? Probably not if the meter is calibrated correctly and has the right transfer curve - I think that's what you were alluding to. Does the engine with the set up described need 30's? No, 24's are more than sufficient. What will happen when turbo(s) go on? I think larger injectors will be needed, the maf will need to be reworked - not just for larger injectors, but for an entirely different forced aspiration set up, and a chip will likely be needed to help with the overall state of tune.
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