I need help with my 4" FP intake

[my98GST]

We all know that the FP intakes doesn't have the recirulation bungs. I don't have the charcoal canister any longer or the stock BCS so those two don't bother me, it's just the valve cover breather that I'm needing to get taken care of. When the motor did run, I noticed a very very very thumpy idle like I had cams, but I'm still on my stock cams. I also noticed that I ran a lot more lean at idle and a lot more rich at WOT with having the valve cover breather left open. What do you guys suggest I do? Is there anyway that I'm supposed to do a catch can that is supposed to fix it or should I just take it to a shop and have them weld a bunch in to it?

 

[snox135]

Some people use catch cans and others don't. I've never seen or heard of it affecting someones car like you are describing. Your PCV is still hooked up to your intake right and if not you did plug the intake port right?

 

[romeen]

I would drill and tap the intake pipe for a 1/4" NPT fitting. Wrap the threads with teflon tape before installing it. Then go ahead and run the vacuum hose from the valve cover to the pipe similar to the stock configuration. This is important for a few reasons:

1) When the PCV system is functioning properly under vacuum the crankcase needs a source of clean air to replace the blow-by vapors that are being sucked out the through the PCV valve.

2) Under boost when the PCV valve closes the crankcase evacuation is performed by the VC-intake pipe hose (the high velocity air in the pipe creates vacuum). Under boost is actually when the most blow-by gases and crankcase pressure are produced. Using a breather filter instead of a connection to the intake pipe for this purpose will not yield nearly as good of results.

3) Since most DSM PCV valves leak under boost above 10 psi or so we can actually have 2 sources of crankcase pressure, blow-by gases and intake manifold pressure. All the more reason why the stock configuration is recommended for relieving this pressure. This is why many guys running the breather filter end up with their dipsticks popping out, blowing oil out of the breather filter, or blowing their valve cover gaskets.

As you touched on it is a good idea (but not necessary) to run a sealed catch can between the valve cover and intake pipe to help keep oily residue buildup out of the IC and IC piping.

 

[my98GST]

Some people use catch cans and others don't. I've never seen or heard of it affecting someones car like you are describing. Your PCV is still hooked up to your intake right and if not you did plug the intake port right?

PCV was hooked up, I have a JMF on the way.....

 

[Cs4g63]

I would drill and tap the intake pipe for a 1/4" NPT fitting. Wrap the threads with teflon tape before installing it. Then go ahead and run the vacuum hose from the valve cover to the pipe similar to the stock configuration.

This is probably going to be the easiest way to fix your problem. You should be able to go to your local hardware store and pick up what you need.

 

[daren_p]

I too would do what others have said of drilling & tapping the pipe for the required barbed fittings, which is what I'm doing with mine but I would recommend 1/8" npt vs 1/4. Its not such an issue with a thicker cast intake compared to thin IC pipe or thin walled intake such as dejontool but 1/4" is to coarse on these to get enough threads to install properly. Even though you should be okay I would still go 1/8 NPT for the extra threads.

 

[romeen]

I too would do what others have said of drilling & tapping the pipe for the required barbed fittings, which is what I'm doing with mine but I would recommend 1/8" npt vs 1/4. Its not such an issue with a thicker cast intake compared to thin IC pipe or thin walled intake such as dejontool but 1/4" is to coarse on these to get enough threads to install properly. Even though you should be okay I would still go 1/8 NPT for the extra threads.

Do you think the 1/8" fitting would allow enough flow for best possible crankcase evacuation? I haven't looked at it in awhile but I seem to remember the nipple on the side of the valve cover as being closer in size to 1/4". I would think that whatever fitting is used it should closely match the i.d. of the VC nipple. Just a thought.

 

[my98GST]

I almost want to have one welded..... What type of metal is the FP intake pipe?

 

[snox135]

Cast aluminum

 

[DoyoFCT]

I wouldn't drill the intake, I would just run a vented catch can, and a constant crankcase ventilation valve instead of the stock valve.

like this one;
http://www.jayracing.com/index.php?main_page=product_info&products_id=15

 

[VanIsleDSM]

Changing the stock system is purely stupid, it should be improved upon, not altered in any way, for reasons romeen mentioned.. vented catch can is the same as running a filter without the oil in your engine bay.. you get no crankcase ventilation under boost, when it's most important..

Think about your open end of the catchcan doing FA while you're boosting, and then think about the vacuum created before the turbo.. all that power just hoovering crankcase fumes out of my engine.

 

[oldman]

I wouldn't drill the intake, I would just run a vented catch can, and a constant crankcase ventilation valve instead of the stock valve.

like this one;
http://www.jayracing.com/index.php?main_page=product_info&products_id=15

Are you suggesting an open window alone will vent a smoky room better than an open window with a window fan attached?

 

[daren_p]

Do you think the 1/8" fitting would allow enough flow for best possible crankcase evacuation? I haven't looked at it in awhile but I seem to remember the nipple on the side of the valve cover as being closer in size to 1/4". I would think that whatever fitting is used it should closely match the i.d. of the VC nipple. Just a thought.

You raise a good point but I think you should be fine with the 1/8" NPT barb as the barb itself comes in different sizes & normally its the barb part that has the smaller ID vs the threaded part. So as long as you can get the proper sized barb required in the 1/8" NPT fitting, I don't think there will be any more restriction vs the 1/4" NPT.

I don't know what size barb is required as my car is still away in storage but when I bring it out in a couple weeks I will be modding the intake, so I will know then which is the best route to go.

As for just running a vented catch can to the crank case vent to add to what others have already stated this will also become a source for unmetered air to enter the motor when in vacuum. This is usually the first thing people are told to check when the are trying to tune their cars & getting strange gm/rev readings. As to how much this or if it will effect your tune, who knows but personally I don't like to make things more complicated then they have to be. The factory hooked it up that way for a reason

 

[oldman]

I love you guys! For a while, I stopped posting in crankcase ventilation threads because I always find myself all alone on this side of the fence, so glad to see things have changed.

I would just like to add that an internal sealed catch can/filtration IMO is mendatory because an oil coated IC can greatly affect your cooling capacity, it is the PCV side that is optional.

 

[romeen]

I'm beginning to understand how you feel Bruce. I don't mean to go off topic but this recent thread about fumes in cabin and oil coming out of dipstick demonstrates your point perfectly.
http://www.dsmtuners.com/forums/showthread.php?t=256594

What is most disappointing is the number of Proven Members not supporting at least the possibility of a pressurized CC being the cause. Sorry for the tangent but given your last post the opportunity to add to the thought was too great to resist.

Regarding your last comment, I have my one catch can between the VC and intake and examination of the IC has revealed absolutely no oily buildup since I've been running it like this.

Daren, I see your point regarding the size of the fitting and you bring up some good observations. Although I have seen barbed fittings in which both the i.d. and o.d. remains constant through the threaded and barbed portions (ie-1/4" diameter all the way through). In theory one could argue that it might flow twice as much as the 1/8" fitting but I don't know for sure whether that is true. Maybe I'll just get off my butt and go measure the VC breather nipple.



Edit: I just measured the nipple on the VC. The i.d. is 6mm or just a hair smaller than 1/4" (.014" less to be exact ). I don't know if the difference between using the smaller vs the larger fitting would be significant enough to make a difference but it seems using the larger one to match the rest of that particular line might be wiser.

 

[oldman]

Regarding your last comment, I have my one catch can between the VC and intake and examination of the IC has revealed absolutely no oily buildup since I've been running it like this.

I was refering to your earlier comment about it being a good idea but not necessary to run a sealed catch can on the breather side.

I'm beginning to understand how you feel Bruce. I don't mean to go off topic but this recent thread about fumes in cabin and oil coming out of dipstick demonstrates your point perfectly.
http://www.dsmtuners.com/forums/showthread.php?t=256594

That's nothing, you should have been here when I first started introducing the idea of re-routing 3 years ago while vented catch cans was the thing to do. Daren probably knows what I'm talking about.

 

[daren_p]

I'm beginning to understand how you feel Bruce. I don't mean to go off topic but this recent thread about fumes in cabin and oil coming out of dipstick demonstrates your point perfectly.
http://www.dsmtuners.com/forums/showthread.php?t=256594

What is most disappointing is the number of Proven Members not supporting at least the possibility of a pressurized CC being the cause. Sorry for the tangent but given your last post the opportunity to add to the thought was too great to resist.

Regarding your last comment, I have my one catch can between the VC and intake and examination of the IC has revealed absolutely no oily buildup since I've been running it like this.

Daren, I see your point regarding the size of the fitting and you bring up some good observations. Although I have seen barbed fittings in which both the i.d. and o.d. remains constant through the threaded and barbed portions (ie-1/4" diameter all the way through). In theory one could argue that it might flow twice as much as the 1/8" fitting but I don't know for sure whether that is true. Maybe I'll just get off my butt and go measure the VC breather nipple.



Edit: I just measured the nipple on the VC. The i.d. is 6mm or just a hair smaller than 1/4" (.014" less to be exact ). I don't know if the difference between using the smaller vs the larger fitting would be significant enough to make a difference but it seems using the larger one to match the rest of that particular line might be wiser.

I think for that size of line the 1/8" NPT won't cause anymore restriction then the 1/4" NPT barb, as even though the ID at the threaded end of the 1/4" fitting will be larger, for the required size of barb, the ID at the barb will still be slightly less or the same as the ID at the threaded end on the 1/8 fitting. (ie the ID won't neck down when you get to the 1/8 fittings threaded section). Yes the ID will expand at the threaded portion of the 1/4 fitting but this doesn't come into play as the barb ID is still the restricting factor.

I have a 1/8" NPT barb here with a 1/4" barb. So for the crank case vent you would want a slightly larger barb, which I'm almost positive they make in the 1/8 NPT but I just wanted to give some measurements. The ID at the Barb end is right around 5mm, while the ID at the threaded end is right around 6.5mm. So you can still go up in barb size before the threaded end posses the restriction. I think the required sized barb will be right at the limit for the 1/8" NPT fitting not causing any extra restriction.

Edit: Actually I just grabed a 1/4" NPT barbed fitting with the same 1/4" barb as the fitting above but this one actually has a slightly smaller ID at the barb end maybe 4.5mm or slightly less. I don't know if this is the standard or probably just differences between manufacturers.

 

[daren_p]

I was refering to your earlier comment about it being a good idea but not necessary to run a sealed catch can on the breather side.


That's nothing, you should have been here when I first started introducing the idea of re-routing 3 years ago while vented catch cans was the thing to do. Daren probably knows what I'm talking about.

Yep I know exactly what yopur talking about . Personally I run a sealed JM fab catch can, one line from the crankcase to the inlet of the catch can & then the outlet to the intake. It keeps the crap out of the intake & everything else is still happy To top it all off, it mounts perfectically on the front side of the tranny where the stupied factory clutch resovoir use to be.

 

[romeen]

Are you suggesting an open window alone will vent a smoky room better than an open window with a window fan attached?

I forgot to mention how much I like the analogy.

it mounts perfectically on the front side of the tranny where the stupied factory clutch resovoir use to be.

Nice! I haven't seen that location used before.

 

[oldman]

See what I mean guys! http://www.dsmtalk.com/forums/showthread.php?t=175324

 

[my98GST]

I think I've got you guys now.. I have a JMF intake mani with no port/bung for the PCV. So i should install a barb on the PCV port on the VC and cap it off, then run one line from the VC breather to the catch can and then the other from the catch can back in to the intake pipe?

 

[oldman]

I think I've got you guys now.. I have a JMF intake mani with no port/bung for the PCV. So i should install a barb on the PCV port on the VC and cap it off, then run one line from the VC breather to the catch can and then the other from the catch can back in to the intake pipe?

hehe, we're both posting in both threads. Just take your JMF to a shop and have them weld on an extra 1/4" fitting so you can also keep your PCV intact on top of connecting your breather to the FP intake, follow this thread to keep your JMF fresh and clean. http://www.dsmtuners.com/forums/showthread.php?t=229338