This is topic inconsistant power under boost in forum Tech Talk at Northern California Ford Owners  .


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Posted by von89stang (Member # 7162) on :
 
hey guys i installed a supercharger on my nearly stock 5.0 about two months ago and it ran great for about a month then all of a sudden it is running weird now. one minute ill step on it and its hella fast and the next minute it barley goes. i am running about 6.5 pounds of boost. also i still have 19lb injectors and and a stock mass air meter with a fmu. it was running great then i put my air filter in the fenderwell to get colder air and thats when it started happening. i moved it back and it still does it. could i have blown my mass air sensor? or what? thanks
 
Posted by Ty (Member # 4920) on :
 
i would definetly think the MAF and injectors are to blame
 
Posted by MikeD. (Member # 8060) on :
 
Yeah von, you need bigger injectors and maf.
 
Posted by MarkOlson (Member # 9556) on :
 
The MAF counts on "laminar" air flow to correctly measure the mass of the air going into your engine. If you put an elbow right in front of the MAF sensor, you cause more, slower air flow in the outside of the bend and less, faster air flow on the inside of the bend and you add some turbulence. All of that means your air flow is not consistent across the cross section of the MAF sensor. That inconsistency is what is giving you your inconsistent results.

Some people also remove the screen on the front of the MAF sensor with the mistaken idea that that screen somehow limits air flow. The screen also helps ensure laminar air flow.

Put a straight pipe in front of your MAF and put the screen back on if you took it off and you should be back to running well again.
 
Posted by von89stang (Member # 7162) on :
 
ok guys thanks for the info. ill try the elbow and definitely get a mass air meter and injectors later. but why did this all of a sudden happen? it was perfectly fine before.
 
Posted by JohnB (Member # 969) on :
 
Have you reset your computer? Also, running boost with stock inj's/MAF/and fuel pump is flirting with disaster...
 
Posted by von89stang (Member # 7162) on :
 
well i have a 255lph fuel pump and a fmu. and i have not reset my computer.
 
Posted by MarkOlson (Member # 9556) on :
 
Make sure you don't have any leaks of metered air.
 
Posted by smokealot (Member # 3108) on :
 
quote:
Originally posted by von89stang:
well i have a 255lph fuel pump and a fmu. and i have not reset my computer.
255 pump is only good for between 370 & 400 hp max! u need bigger injectors w/matching mass air.
 
Posted by 2stangs69-91 (Member # 1951) on :
 
hmmmm I ran 10.8 with a GSS340 255 fuel pump? good for only 400 hp? I would almost look into belt slipage. If you have a bypass valve I might look into that also. Do you get any black smoke out of the pipes?
 
Posted by von89stang (Member # 7162) on :
 
im gonna go ahead and check for air leaks today. oh and i thought it was belt slipage too but i checked my belt and it seems good. i get some white smoke out of the pipes. oh and yea i am definetely gonna get bigger injectors and a mass air meter.
 
Posted by MikeD. (Member # 8060) on :
 
Looks like me and you got a race on our hands!.. Can't wait untill Sac opens up!
 
Posted by von89stang (Member # 7162) on :
 
lol i know man, cant wait!
 
Posted by 92_5.0 (Member # 7624) on :
 
quote:
Originally posted by von89stang:
im gonna go ahead and check for air leaks today. oh and i thought it was belt slipage too but i checked my belt and it seems good. i get some white smoke out of the pipes. oh and yea i am definetely gonna get bigger injectors and a mass air meter.
White smoke can be a sign of a blown head gasket, how is your engine temp? any water in the oil? I blew a head gasket on my near stock motor when I first put on my vortech. Also have you checked your plugs? Under WOT the FMU maximizes the injectors and causes the motor to run rich and will shorten the life span of your spark plugs. Are you running a colder plug?
 
Posted by 92_5.0 (Member # 7624) on :
 
Also if its a self contained blower like vortech, etc. they tend to heat soak and you notice a power drop when your running it hard.
 
Posted by jph331 (Member # 665) on :
 
quote:
Originally posted by 92_5.0:
Also if its a self contained blower like vortech, etc. they tend to heat soak and you notice a power drop when your running it hard.
Don't you mean like paxton superchargers being self contained as in the oil. Vortech shares the oil with the engine. Maybe you meant non intercooled such as vortech. Procharger would be intercooled.
Also another problem I recall from the past was the dryer type hose that came with the vortech kit collapsing under boost and killing the power.
 
Posted by East Bay 50 (Member # 8081) on :
 
quote:
Originally posted by smokealot:
quote:
Originally posted by von89stang:
well i have a 255lph fuel pump and a fmu. and i have not reset my computer.
255 pump is only good for between 370 & 400 hp max! u need bigger injectors w/matching mass air.
he said the car is basically stock except for the blower. I don't think he is pushin 320rwhp with just the blower but even if he is a 255 fuel pump is more than capable of keeping up. I have seen plenty of setups with 500rwhp use 255 pumps...
 
Posted by 92_5.0 (Member # 7624) on :
 
quote:
Originally posted by jph331:
quote:
Originally posted by 92_5.0:
Also if its a self contained blower like vortech, etc. they tend to heat soak and you notice a power drop when your running it hard.
Don't you mean like paxton superchargers being self contained as in the oil. Vortech shares the oil with the engine. Maybe you meant non intercooled such as vortech. Procharger would be intercooled.
Also another problem I recall from the past was the dryer type hose that came with the vortech kit collapsing under boost and killing the power.
WOOPS, meant non-self contained because they use hot engine oil, thanks for catching that [patriot]
 
Posted by 89Rodknocker (Member # 2951) on :
 
Your gonna need to step up your injectors, I have a set of 24'S and meter and 30's with meter. Then you can ditch the fmu.

Also if the intake hose doesn't have a leak and is not soft to where it can colapse and restrict air flow. I'd look into belt slip anderson ford motorsports sells belt slip juice. Or go and buy some vht track bite and place a couple of drops on the belt. Also have you retighten the belt yet?

I had the same issue with a serp belt on mine and ended up going back to cog.

Just a few things to look into.
 
Posted by von89stang (Member # 7162) on :
 
yea i have tightened my belt a couple of times. oh and i have the dryer type intake hose also. and my oil is good, water temps is cool. i do have new stock plugs in it.
 
Posted by onesicklx (Member # 285) on :
 
quote:
Originally posted by East Bay 50:
quote:
Originally posted by smokealot:
quote:
Originally posted by von89stang:
well i have a 255lph fuel pump and a fmu. and i have not reset my computer.
255 pump is only good for between 370 & 400 hp max! u need bigger injectors w/matching mass air.
he said the car is basically stock except for the blower. I don't think he is pushin 320rwhp with just the blower but even if he is a 255 fuel pump is more than capable of keeping up. I have seen plenty of setups with 500rwhp use 255 pumps...
i was making 380rwhp with only a 255 intank fuel pump and 42lbs injectors...tuner told me the car needed more fuel...????
 
Posted by von89stang (Member # 7162) on :
 
damn thats crazy
 




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