WTF? im building mad boost in neutral!?! [Merged 12-7]

[98TsiAWD]

I want to test my pcv valve under boost. Is there anyway I can get the turbo to boost by reving the engine under the hood?

I recently blew out my dipstick, I did a leakage test and my intake valves are sticking open a little so that would mean boost is getting in there when it shouldnt be right? Causing excess crankcase pressure.

My valve cover breather works fine, I pulled the pcv valve, I can blow through it easily, I also pulled the hose that goes from the pcv to the intake. I make sure it and both fittings where not clogged.

So, basically i want to have the engine under boost just for a second to see if the pcv blows off excess crankcase pressure. But being as there is boost in the intake that will keep the pcv from opening wont it? So my intake valves sticking open is what is causing excess crankcase pressure?

 

[exzercist]

Allright, BOV sounds aside. I'm more concerned that his bone stock 2G with an HKS BOV is venting into the atmosphere. That thing's gonna run like $hit, stumble and run rich like that. My last concern would be how much boost his 2G is making. If you want that sound, it's gonna cost you

why does everyone say that the car gonna run like crap? ive seen and logged bov venting into the atomosphere. yes they run rich but i havent seen out of 2 dsms i own and two more that i know the guy modded them, they never stumble or anything. they just run rich, which can be solved with a gm maf and translater.


Oh yeah i forgot a cop tried to make me rev my engine to "hear" my exhaust. i tell cops that i can ### itll neutral boost and they sit there scratching there head with their finger in their a$$hole like a retarded monkey. they think im trying to bull$hit them and i always argue with them. most cops are pricks and have no idea what there talkin about. especially they have a built in Decibal reader in there head.

 

[Hideki]

When I test drove my 2G which had aftermarket boost pipes and a BOV that vented into the atmosphere the car wouldn't even accellerate without hesitating. When they installed the factory pipes and BOV with recirc. the car ran wonderfully. Yes, you can vent your BOV into the atmosphere with the GM MAF and translator (this is the "cost" I was talking about) but the 2G in question in this thread is using his factory MAS and venting his BOV. <--- not a good idea from a performance standpoint. If you want the BOV sound with your stock MAS try and install a hard intake pipe (have you ever looked into your stock intake pipe?)

 

[exzercist]

When I test drove my 2G which had aftermarket boost pipes and a BOV that vented into the atmosphere the car wouldn't even accellerate without hesitating. When they installed the factory pipes and BOV with recirc. the car ran wonderfully. Yes, you can vent your BOV into the atmosphere with the GM MAF and translator (this is the "cost" I was talking about) but the 2G in question in this thread is using his factory MAS and venting his BOV. <--- not a good idea from a performance standpoint. If you want the BOV sound with your stock MAS try and install a hard intake pipe (have you ever looked into your stock intake pipe?)

well i have my vented and my car runs fine i logged it and it runs a little rich right after i shift a little rich wont hurt anything. my car never hesitates and or bucks. the car has a lot of power. you also dont know if the blow off was setup right (spring tension) and the vacum lines could be not hooked up. you don know what sum idiots do to there cars.some $hit scares me .

 

[Deadly BlaZe]

well i have my vented and my car runs fine i logged it and it runs a little rich right after i shift a little rich wont hurt anything. my car never hesitates and or bucks. the car has a lot of power. you also dont know if the blow off was setup right (spring tension) and the vacum lines could be not hooked up. you don know what sum idiots do to there cars.some $hit scares me .

Are you automatic? I know several auto people who vent their bov without the proper setup and they run fine. I'm manual and I tried venting mine before but it stalled after every shift If i didn't shift quick enough.

 

[exzercist]

Are you automatic? I know several auto people who vent their bov without the proper setup and they run fine. I'm manual and I tried venting mine before but it stalled after every shift If i didn't shift quick enough.

Nope, both my cars are standard and the other two are auto and manual. i guess i just got the good batch of dsm, .

 

[mini zilo]

How come the car does not build boost when there is no load on the engine? This is obviously something I have known for a very long time, but honestly I can say that I never understood WHY you cant build boost with no load on the engine?

 

[Mr Peepers]

Boost is essentially air piling up faster than the engine can take it in. You will notice there is still some air let out by the BOV even when free revving, the turbo is still moving air, but not spooling quicker than the engine is gaining revs. 2 step, I'm not sure. I had a thread on turbo theory and I spitballed some ideas, but no definitive answers why stutterbox builds boost in nuetral. http://www.dsmtuners.com/forums/showthread.php?t=261920&highlight=turbo+theory

 

[Defiant]

"Boost" means "More Air Being Forced In Than The Pistons Can Get Away From".
You must have a load on the engine, something holding it back, in order to back up air in the intake.
Trying to boost with no load is a very, very bad thing. But your bearings will explain it to you more clearly than I can.

Picture yourself trying to run down a steeper hill than you can keep up with.

 

[Mr Peepers]

Trying to boost with no load is a very, very bad thing. But your bearings will explain it to you more clearly than I can.

Picture yourself trying to run down a steeper hill than you can keep up with.

Can you please elaborate on this? I've heard free-revving in general is bad, but never seen/heard any explanation. Does this include stutterbox? Do you know the theory behind how it builds boost in neutral?

 

[Defiant]

A stutterbox will build boost by having the "stuttered" cylinders produce a load on the intake.

Engines don't like to be run without a load on them. Things whip, from the crank to the cam drive, to the auxiliary drives to the clutch assembly.

 

[thekellbeast]

Engines don't like to be run without a load on them.

Our Engineering Officer cringes every time they decide to idle one of our engines through the night.

 

[UsMarine20M]

So stutered builds boots and free reving doesnt am i getting that right?

 

[Spyder4g64]

"Boost" means "More Air Being Forced In Than The Pistons Can Get Away From".
You must have a load on the engine, something holding it back, in order to back up air in the intake.
Trying to boost with no load is a very, very bad thing. But your bearings will explain it to you more clearly than I can.

Picture yourself trying to run down a steeper hill than you can keep up with.

I can build 15psi reving my motor in neutral. No 2 step.
As far as the motor building up more pressure than can be put out, i dont believe it.

The motor at 2500rpms rev'ing in neutral, WOT, is the SAME speed as 2500rpms in 2nd gear, WOT. No?

The port sizes arent smaller while not in gear, so therefore throw that theory down the drain. Its moving the same amount of air regardless.

The concept of how load works, and why, is a VERY, VERY hard thing to explain, and understand. Neither of which I can do.

But as defiant said, let your bearings explain it to you

 

[mini zilo]

I can build 15psi reving my motor in neutral. No 2 step.
As far as the motor building up more pressure than can be put out, i dont believe it.

The motor at 2500rpms rev'ing in neutral, WOT, is the SAME speed as 2500rpms in 2nd gear, WOT. No?

The port sizes arent smaller while not in gear, so therefore throw that theory down the drain. Its moving the same amount of air regardless.

The concept of how load works, and why, is a VERY, VERY hard thing to explain, and understand. Neither of which I can do.

But as defiant said, let your bearings explain it to you

I can tell already that you are not a very knowledgeable person. Half of what you just said is wrong.

 

[dsm-onster]

I can build 15psi reving my motor in neutral. No 2 step.
As far as the motor building up more pressure than can be put out, i dont believe it.

The motor at 2500rpms rev'ing in neutral, WOT, is the SAME speed as 2500rpms in 2nd gear, WOT. No?

no.

How much throttle does it take to rev to 2500rpms? How much throttle does it take to keep it there? Is that same amount of throttle neccesary to take the car down the road in 2nd gear?

Consider this. Does it take the same amount of air and fuel mass to rev a set of pistons, rods, flywheel, and accesories to 2500 rpms as it does to propel the car down the road? No. The small amount of mass and heat neccesary to drive the engien rotating assembly alone is not enough to spin a turbine to any good rpm to develop boost.

 

[Littlebeeper]

figure out how to control the wastegate and you may figure out how to make a bit more boost while fre-revving. by the way, its built to not do it for a reason. I'm sure you will figure out why if you try it

 

[dsm-onster]

I'm no dummy. I know what you are saying , but . . .

The motor at 2500rpms rev'ing in neutral, WOT, is the SAME speed as 2500rpms in 2nd gear, WOT. No?

That is wrong. Many of these guys need clarification on this. The rest of us know what to do and should help them when asked .

 

[Eclipse98_RS]

Ok im by no means an expert on anything BOV related. My car doesnt build anything when im neutral, but ive noticed on some of the cars you see in movies do. I think its badass the way they sound when they do that. Im not gonna go out and do it to my car, but how does this happen? All ive heard is really kinda just not helping.

 

[dsm-onster]

Well, search for antilag and drag racing or studder box and drag racing. . .

 

[Gregory]

Ok im by no means an expert on anything BOV related. My car doesnt build anything when im neutral, but ive noticed on some of the cars you see in movies do. I think its badass the way they sound when they do that. Im not gonna go out and do it to my car, but how does this happen? All ive heard is really kinda just not helping.

What movies? That's just the magic of Hollywood... You will also notice in the opening scene with the eclipse in "The Fast and The Furious" that he shift about 9 times before toping out in one pull. Don't worry about what happens in the movies.

 

[dsm-onster]

What movies? That's just the magic of Hollywood... You will also notice in the opening scene with the eclipse in "The Fast and The Furious" that he shift about 9 times before toping out in one pull. Don't worry about what happens in the movies.

Yea, longest 10 seconds i've ever clocked .

 

[Gregory]

Haha, yea. 10 second car my a$$

 

[dsm-onster]

ALL of them, your a$$! If I owed someone a 10 sec car, I'd be swimmin' with da fishes in the hudson river. (I crack my self up early in the morning)

 

[McFox]

What movies? That's just the magic of Hollywood... You will also notice in the opening scene with the eclipse in "The Fast and The Furious" that he shift about 9 times before toping out in one pull. Don't worry about what happens in the movies.

Or how when he tops out he is magically put into a spin.

So on topic, is it bad to be able to build around 5 pounds of boost in a free-rev?

 

[Street_Killer]

Ya, Im wondering the same thing. Ive done it a few times messing around. If you free rev up to like 5k you get a little boost.