No joke, i am building boost in Nuetral!!!

[CH152]

(I'm not for sure if i am the first one to come across this or not?)

I really was not paying attention to my Boost Gauge in Neutral until today. Yesterday I had installed a MBC from Mc Coy Motorsports www.tobefast.com . The name of the MBC is Applied Technologies & Research, INC CV100A. Anyhow according to the instructions you are to remove both line on the BCS valve and set them aside. The two lines you took off the BCS valve, the upper one I think goes to the bottom of the intake going towards the turbo inlet (plug that nipple off on the intake with a vacuum line and a screw) and the bottom one goes to the turbo and has a T fitting, one line goes to the Wastegate and the other goes to the bottom of the turbo compressor. Now back to the installation: My MBC came with a controller and one line that splits in a Y fitting. One goes to the Inlet on the Turbo compressor and the other one goes to the wastegate, which technically is a signal port, which then commands the wastegate diaphragm to lift or open. After its installed ty-rap the vacuum lines from the MBC so you can’t get any leaks. HOW IT WORKS: Opening the valve bypasses air away from the wastegate/signal port. The restriction in the “Y” is being worked against by air bled away with the valve, Simple and effective. The 2 nipples on the BCS I just left untouched. When I was looking at my boost gauge in Neutral I was building 13 PSI ( I had my foot in the gas though, when i wasnt touching the throttle it was pulling -18 pounds) no joke about it. I don’t know exactly why it is but the turbo is now boosting when I am at the line before I take off ( foot on the gas at about 4500 rpm). Pretty neat huh? Let me know what you guys think. Here is a pic I made to help some in the explanation.

 

[jw]

No joke, you paid $40 for a bleeder valve type boost controller???

 

[CH152]

Yeah, that to much or something? I think the exact total was 41.34 but yeah i guess thats what it is. He said its what he uses and he as a 4.3 GMC cylcone motor that has a custom turbo on it. It set the world record for that motor i think at 9. something it was a real low 9 though.

 

[diamondstar36]

Heh. You've noticed what we all did. Turbos spool with exhaust gas, not forward motion. Rev the motor and the turbo will spool. You never noticed before because your stock boost guage is a useless POS. It's controlled by the ECU, no actual boost pressure. And yea, 40 is a little much for a typical MBC. You can make your own for around 9 to 15 bucks at Home Depot. I didn't feel like wasting the time and bought a JoeP on Ebay for 20.

And yea, Syclones can be hella fast. One of the local DSM guys around here has one. With a 20G he runs 11s easy.

 

[CH152]

Let me clear something up here. I wasn't looking at the stock boost gauge. I have one from VDO mounted in dual pillar with a blinking light show. Anyhow i though i would clear this up a bit when i say i am building boost in neutral. It builds when i floor it wide open throttle and take it to 4500 or even more. I have to hit the gas hard though. On the VDO boost gauge it reads at -18psi at idle to 13psi when i hit the gas. It doesnt jump there either. It kinda delays and then it winds up to that. How many of you can build 13psi in nuetral NOT FOWARD MOTION? and yes i do realize that the stocker boost gauge is the ecu's estimite as to what is going on with the turbo thats why i bought a aftermarket one. Before i installed the MBC i was getting well no boost to show up at all on the VDO gauge it went from like -18 to -5 when i hit the gas, if you really call that a gain then sure it boosting/spooling in nuetral. But what i am saying is, after i installed the MBC The VDO boost gauge Reads 13psi under WOT, and when i pop the hood and manually open the throttle i can grab ahold of the UIC after the 1g BOV and litterally watch the pipe expand, and having my friend in the car watching the Boost Gauge the VDO one while i am manually opening the throttle at WOT he says " your hitting 13 man"... ((((oh, and did i mention that i can hear the BOV after i release the throttle under the hood of the car. anyhow. Is that normal?))))

hope that clears that up for you that are reading this.

 

[DSMJim]

your building 13psi in neutral? I have never heard of any normal street car being able to do that.

 

[CH152]

I dint believe it either cause i was reading another forum awhile ago about how to get your car to build boost in nuetral and this guy was getting flamed all over the place. And someone told him to get a friend to hold on real tight onto the crankshaft while you hit the gas. I thought it was funny. But yeah the two nipples coming off BCS i have jsut open to dead air. Maybe that is what is causing it to do this. but that picture is pretty much how i hooked it up. The MBC came with one hose that split into a "Y". And you look at the Hallman MBC or others they have two lines. But oh well i aint complaining if it is building boost in Nuetral. I jsut need to know now how to put the extra power at the line to the road with out my tires spinning off the wall redicuisliy like they have been after i installed the MBC. I lowered the PSI in each tire down to about 21. It hooked up better but it felt slower. I will try 25 next and see what it does.

 

[LaserRST]

Well mechanically I would think that this could be accomplished by disconnecting any wastegate signal and trying it. Maybe some one should try this an see if its true .... as for me I wouldnt ever rev my car up that high with no load.

 

[insane147]

i can do it but i run a stutter box......perhaps your dumping too much fuel in.

 

[CH152]

Dumping to much fuel in what you mean by that. are you talking about where it kinda hesitates then it builds real quick. Its not like a stuttering sounds it just spools slow and then it builds to 13psi. The air blowing in though is real hot if the turbo was run for a while. There is no air being blown thru the Intercooler so the air in my guess is damn hot. As to reving the car up to high. i think 4500 but below the redline is safe as long as you dont do it repeativley.

 

[taylorspl]

I can hit 11psi free revving my car in "neutral" without FORWARD MOTION or whatever you are thinking, and I am on stock exhaust.

The hesitation you are seeing is the transition from vacuum to boost, it takes a second to goto positive manifold pressure.

 

[Boostspike]

i've seen my buddies supra do it but he was in rolling motion then popped it into N.. but i've never see anyone do it from a stand still..

 

[Oreopride18]

When I was looking at my boost gauge in Neutral I was building 13 PSI ( I had my foot in the gas though, when i wasnt touching the throttle it was pulling -18 pounds)

Sounds pretty normal idle (-18 vacuum) As for building boost on the line....

I remember a few months ago that either on this board (or it might have ben talk.com) there was an argument about building boost on the line. Some of the manual guys said it was possible to do it.

Boostspike i've seen my buddies supra do it but he was in rolling motion then popped it into N.. but i've never see anyone do it from a stand still..

Did he backfire while this happened? In Lancer WRC cars they have something nicknamed the "bang-bang" system that is used for their rally sprinter races. The system injects fuel into the manifold (Don't flame me just yet; bare with it) and forces the car to backfire. It usually does it twice, hence the bang bang name. The sudden violent explosion causes the turbo to stay spooled. A manual that doesn't lose boost between shifts! *sigh* It's pretty obvious why this would never work on a street car. The manifolds tend to melt and make it only through one race (or about 200 miles for a good sprinter one) I always wondered if there was a way to make a street-safe system like this. Like the spark plug in the exhaust pipe trick; only a *bit* farther up into the system I think I'll keep dreaming though.

 

[insane147]

a stutter box does it just fine, its built in to most ignition boxes. no lift to shift between gears and build boost on the line in N.

 

[Rob]

sounds good to me .......sounds like a kick ass jump off the line too ...well if you can keep the wheel spin down =)

 

[sophat34]

I looked in to stutter boxes, correct me if I am wrong, but boost of the line isnt all that good for transmissions. from what I was told a boost of the line will leave parts behind. I already broke one tranny, well 1st gear any way.

 

[98TsiAWD]

So this MBC isnt even hooked up to you BOV? or is that what you named wastegate in your pic? I'm confused...but all I know is that I would like to build boost off teh line sometimes.

 

[CH152]

THe pic i attached is what it says. My MBC i bought is not attached to the BOV in any way at all. THe only line thats off the BOV goes into the intake plentum after the THrottle body. THE MBC is attached by one line on the comprosser side of the Turbo and the other line going to the Wastegate, the brass looking thing on the T25 of mine. If that clears that up any at all. Theres 2 problems i can see by building boost of the Line. 1. is the tires holding that much more power from a dead stop. and 2. the tranny putting it down to the road or handling the sudden torque being applied to the ground. One thing i noticed is that the bosot varies in weather. When my car is indoors it can get to about 11 but makes 10 for sure. BUt out in the cold with 93 octane and Nitro Power Fuel additives which i am impressed with which is suppost to add 25 horsepower per bottle. anyhow it could reach 13 PSI and get 12 for sure. I turned the MBC down like one notch cause i was getting fuel cut this morning in the cold weather. But as of now with the settings i have i can get 11psi(MBC TURNED DOWN) at the line without a problem. its jsut a matter of trial and error of hooking it up to the grown w/o wheel spin.

 

[nine5raptor]

Something isn't right...you shouldn't be able to build that much boost in neutral. I bet your clutch isn''t disengaging completely. Boost is load dependent. If you have a large heavy engine and free-rev, I could see you building boost, but only like 8 psi or so. I can't even get 1 in neutral (on the T-25 or the small 16G). You have a load on the engine (some of it is inertial) but you shouldn't have enough to build 13 psi.

BTW bleeder valves are bad for spooling. I switched to a ball and spring controller (used to have a setup like yours with a fish-tank valve) and the turbo is much more responsive.

 

[CH152]

Well, the turbo is responsive still, i feel as if the thing is actually quicker. i had to turn the overall boost down on the valve cause i was getting into real bad fuel cut in the cold air because it ficking snowing the piss of out here. i aint complaingin though good to do dounuts. anyhow, if i could get a video to show you all i would but our technology in kentucky is not to advanced where i am from. Anyhow, i am not complaing about it building boost in nuetral. its not like i barely touch the gas in nuetral i go from idle and floor it and it builds up. Its confusing at first reading all this abotu how it works, but it shocked the piss out of me cause i didn't think it was possible without one of those stutter boxes some people have.