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Discussion Starter #1
I have a 1990 supercharged 5.0 mustang. I had a question. What is the best thing to do about the crank case venting. Should I run a line from the oil filler neck to the inlet elbow on the S/C and cap off the PCV valve OR should cap the oil filler cap and the PCV valve and put a screw air filter on top of the oil filler neck? I need help here. Also my car is having a REALLLLLLLY hard time idling. It didnt have a hard time idling before the S/C. It idles at like 500 rpms then dies. MY mods are : AFR 185cc heads, trickflow stage 2 cam, BBK SSI intake, Vortech V-2 SQ S-trim w/ UPR power pipe, 1.6 RR, 24 pound injectors and FMU, BTM box ( came with kit), 75 mm Pro-M MAF

Note: I have 42 lb injectors on the way with 80 mm MAF sensor and a tune
 

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the pcv is at the back of the intake but if u have forced induction u should just get a breather filter on one of your valve covers cause u will have pressure insted of vaccume in your intake so pcv wont work that well i wouldnt think..
 

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not sure i havent had much expiernce with superchargers.. do u have the stock FPR on it?
 

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OK, here is what you do. You cannot have a breather and PCV at the same time, you will be sucking unmetered air into the crankcase and into the intake from the PCV.

But you can run PCV with a check valve such that under boost it blocks pressure from going to the PCV, under normal driving conditions it will work normally.

However, that leaves you with no crankcase ventilation under boost. So you run a line from the valve cover to the blower inlet, but also with a check valve so it can only blow air out of the crankcase and not suck air into the crankcase and into the PCV. Also, it doesn't hurt to run a fuel filter on this line to keep and oil vapor out of the supercharger piping...which eventually will coat everything including the MAF.
 
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OK, here is what you do. You cannot have a breather and PCV at the same time, you will be sucking unmetered air into the crankcase and into the intake from the PCV.

But you can run PCV with a check valve such that under boost it blocks pressure from going to the PCV, under normal driving conditions it will work normally.

However, that leaves you with no crankcase ventilation under boost. So you run a line from the valve cover to the blower inlet, but also with a check valve so it can only blow air out of the crankcase and not suck air into the crankcase and into the PCV. Also, it doesn't hurt to run a fuel filter on this line to keep and oil vapor out of the supercharger piping...which eventually will coat everything including the MAF.
ryan u are so wise :) i knew u would come through with an answer
 

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Discussion Starter #8
yeah the FPR is stock but I have a FMU for it so it controls my fuel pressure under boost and I was thinking just run a screwin air filter in the oil filler neck and plugging the pcv valve system. Will that work?
 

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And where do I get a check valve from. Do they make them stock on a certain car and how do they hook up?
I got my check valves from US plastics or something like that. On line, they were like $2 each or something.


http://www.usplastic.com/catalog/pr...e=usplastic&category_name=45&product_id=15641

Yes you can run just a breather and no PCV, but you should have a breather on both valve covers and you will have to deal with the oil vapor that gets vented all over the top of the engine.
 

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Discussion Starter #11
so is this my idleing problem? I have gone through all the normal things that makes a car not idle right. This car has a good size cam and when it tries to idle at 800 rpms the cam lopes so hard it wont. Note it idled fine before I put this S/C and it pops in the exhaust every coupe seconds when you first crank it up. Detenation?
 

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Detonation at idle??? I hope not or you would never make it to 2000 rpms.

More likely your timing is off. Also, did you replace the MAF or injectors? Sounds like you are getting too much fuel or you changed some part of your fuel system but have not adjusted for the change.
 

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Discussion Starter #13
Well right now I havent touched the fuel system EXCEPT FOR the FMU that came with the Supercharger. I checked my timing it is set a 10 degrees and I also have a BTM box. any experience with that. I have the starting point on the box set at 2 and the knob inside set at 3
 

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So that means you have 2 degrees pulled all the time and 3 degrees per pound of boost right? (I have the 6al-BTM, which only has the one knob). If that is the case, turn the knob on the box to zero, otherwise you are at 8 degrees initial, which is too little base timing and will cause the poor idling you mentioned.

Edit: Also 3 degrees per pound of boost is a lot of pulled timing. At 10 lbs of boost that is 30 degrees!
 

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Discussion Starter #15
the knob in the car or the knob on the box. I think the knob on the box goes from 0-5 and the knob in the car goes from 0-3. What should I set the numbers on. Right now I have saw 8 pounds, 7 and 5 pounds I dont know why it is changing but it is. Can you tell me what to set it at for 5 pounds for now
 

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Yeah, I went and read the directions for the BTM. Actually it is setup OK they way you have it. It should kick in at 2 lbs of boost and retard 3 degrees of timing for each additional pound of boost, so at 5 lbs you will be pulling 9 degrees of timing.

As far as the boost level changing, double check all your hoses and clamps coming from the supercharger. Also make sure your belt is in good shape.

I would consider bumping the timing to 12-13 degrees and setting the knob on the box at zero and the dash knob at 2. That way you will have more base timing, but for each pound of boost you will still be taking away 2 degrees. So at 5 lbs of boost you will be taking out 10 degrees.
 

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Discussion Starter #18
you dont think I will detonate do you? I cant hear if it detonating now or not. With the engine being so loud thats all I hear
 

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you dont think I will detonate do you? I cant hear if it detonating now or not. With the engine being so loud thats all I hear
Listening for detonation is a bad way to find out, because if you can hear it, you could be too late. checking your plugs is the best way. Look for little dark specks on the porcelain. these are created from multiple flame paths caused by detonation. They will be best viewed immediately after a WOT run. Little specs of aluminum mean you are blowing holes in the pistons and it is too late.
 
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