Bypass The Compressor For Quicker Spool?

[kimokalihi]

Tell me what you guys think of this setup. I've been speaking with a guy I met on facebook through the PNW AWD facebook page when I saw his Scion TC that he swapped a turbo Celica engine and AWD drivetrain into. He says he has figured out a way to reduce spool time several hundred RPM allowing one to use a larger turbo and not have to deal with a ton of lag.

It seems to make sense to me but I'm not that smart so perhaps you guys with more knowledge of turbo systems can give some chime in here. The basic idea is to bypass the compressor wheel of the turbo with a diverter valve allowing the engine to act more like a naturally aspirated engine initially and then once the turbo has spooled to a point where it's creating positive pressure in the intake system, then the valve closes to change the path of airflow back through the compressor like normal. He says the compressor wheel and turbo is creating a restriction in the intake and that bypassing it will allow the turbo to spool quicker and make more power in the low end before the turbo kicks in.

His name is Petrie Taitano. Here's a clip of text he wrote on a video (can't share the video because you have to be friends with him to see it on facebook) demonstrating the valve in action on his car.

"about an invention i was working on...so with a bit of thought about what i had been working on so hard but never actually was able to do anything with due to financial ability, some peoples stubborn idiotic nature refusing to even look at it because im some nobody.

also it has hit the time frame where it has become public domain and un patentable... so it is what it is

i have also struggled with sharing this.. but i would rather you saw this from me than some butthole at some performance shop..

what i had been working on was a way to provide oxygen to the engine without bottle necking it at the turbo which most of the time at a dig or while taking off without break boosting or pre-spooling and it isn't spinning enough to provide any real air or oxygen, even when you mash the gas pedal.. theres still a lack of time in which the motor gets that suppressed feed of air and in turn finally spins up the turbocharger.

this effect is more drastic as you up-size the engine liter or displacement vs the turbocharger sizing..

one friend reported a 700 rpm spool time decrease with a much larger turbocharger.. i have the opposite a mid range 60 ish ar turbo.. and because of this it spooled at a stop just blipping the gas.. with a light weight flywheel and in neutral.

but literally what i was working on i guess had been semi developed before in a small part by a guy named dan caulkins and unknown to me the fact that it had been thought of about 8 years prior.. the difference well the difference was.. his valve idea used an intake and valve that had almost a maximum of a 1 inch orifice... unknowingly i developed a very similar system that used an almost 2 inch intake orifice an unsprung valve (his was sprung which defeated some of the vacuum relief ).. which seems not so amazing until you start seeing how it worked in total..

the end result of his work was the general idea and thought that it would never work.. people dogging the idea and generally calling the "d valve" a joke that did fuck all.. and the reason is no one bothered to take it to the practical level or do any real digging..fixing flaws restrictions and diameters. as i have done..

so instead of nay saying and crap i was met with enthusiasm. from people in varied Fields.. engineers, tradesmen, etc... none of which could argue it in a bad or negative way.. and quite the opposite most agreed it could only assist and it has..

example:

imagine an ls (corvette engine) with a decent sized turbo.. in most cases.. the car needs some serious revving or brake boosting in order to spool or even take off with any force...with this device yeah you can still brake boost rev, but what you can do is punch the gas without any of that... and the engine just works like a non turbo car because until the turbo creates boost it is a non turbo car with this item.... in fact because of this the turbo snaps into function faster because the motor can load up the cylinders and manifold faster... much much faster.

seems stupid and simple but in reality its what it is.. something that worked well enough for me to walk on subarus, mercedes amgs, boosted civics, evo's, etc..

so think im crazy if you want.. but the proof is where it is.. i will post some vids showing it work.. just remember they are old.. and yeah that manifold is what it was.. a leaky piece of crap.. now imagine knowing that it was horribly leaky and i could still spool by just hitting the gas,

one last thing to observe. in this video you see the valve actuating like mad.. well if the turbocharger was ever providing more air than the motor needed that flap would NEVER OPEN....enjoy"


"heres something i was working on because my car did that same shit when i first boosted it.

the drawing and diagrams in the comments explain a lot of how it works. but in reality a turbocharged engine relies on a spooled turbo to breath. unfortunatley most turbochargers need to spool to allow air to even let the motor idle..

i did a test on a friends 2jz we hooked up just the coldside to see if the car would even idle.. with a stock na exhaust.. the car would not start"




Here's the valve he's using : http://www.ebay.com/itm/NEW-JANDY-7305- ... 1e8e04b895





Here's his build thread on the TC : http://www.scionlife.com/forums/regiona ... al-229358/





Here are a couple diagrams he made of how the system functions and a shot of his engine with the valve installed and operational.

[mike-tracy]

I'm not that smart either, but a pool checkvalve? really?

I think you'll be very happy with more displacement, and that will help your spool tremendously. Also, what about twinscroll turbos? Kinugawa (spelling?) sells a conversion housing where you reuse your td05/6 as a twinscroll. Lastly, what about EWG's? Those will help spool from my reading.

I'm not totally discounting his work, I just really think if there were "shortcuts" to faster spool and more power, more people would have picked up on it by now.

[kimokalihi]

My thinking was this is a pretty simple solution for a very common problem. I would imagine the engineers of major auto makers would have thought of it. But who knows maybe he's on to something.

[mike-tracy]

Too bad you didn't get to ride in Steven's last SS. It had ej20k heads and a 9.x:1 CR built ej255. Heads combustion chambers were modified to ej25 size. That was a beast off the line. Hell, it had power everywhere.

[kimokalihi]

Nice but that's a hell of a lot more expensive than this. My ss used to have a decent bottom end with the stock forester block 9:1 but now it sucks and it's slightly embarressing.

[mike-tracy]

Yeah there's that, lol. OK I hope others have input on this.

[kimokalihi]

For what it's worth he told me that valve is rated at 128 psi.

[James614]

I've thought of this myself, I never knew anyone went through all the research and work to actually fit a working system onto a car.

While more displacement, higher compression, twin scroll, EWG's, etc all help spool time, IMO it's that much more awesome if you can add one more item into the mix to drop spool even more.

I'm VERY skeptical of claims of dropping spool by 700rpm. But there's so many dynamics and variables involved with that, I honestly couldn't even begin to try and argue it's validity. But the basic idea seems pretty solid. The compressor is not a very ideal oriface for air to pass through when it's not being actively pushed through by the wheel.

My one big question: Doesn't the OEM Subaru, as well as most other factory/OEM recirculating style bypass valves, already stay open under vacuum? This would achieve the exact same thing, excepting that the OEM BPV's typically used are very small and do not flow nearly enough to feed the engine without much restriction. Maybe I'm wrong about the operation of the OEM BPV's but I'm very certain I've read that they open under vacuum and that's why the car runs like total ass if you just vent it to atmosphere.

[kimokalihi]

I'm not sure if they're open in the situation you're talking about but an oem bpv sends excess air from after the turbo back into the turbo so it's not really doing the same thing as this. This is eliminating the cold side of the turbo from the intake tract altogether. Any and all air in a standard system has to go through the turbo to get into the engine, bpv or not.

[James614]

In the diagrams, there is nothing actually blocking the cold side of the turbo. The majority of air would just flow through the valve because it has the least restriction.

As far as BPV vs a check valve, they are plumbed in the same way. The BPV does vent excess pressure back pre-turbo, but if it stays open under vacuum air can flow the opposite direction and also bypass the turbo going into the engine.

I bring this up because I feel like it shouldn't be a stretch incorporate some sort of BPV-based setup that achieves the same thing compactly on our TMIC setups, if you can find a BPV large enough to allow that much airflow. Our requirement shouldn't be nearly 2" for good result, since our turbo inlet is only like 1.75" and is obstructed by the compressor wheel.

Unless I'm wrong about the BPV being open under vacuum of course. Then I'm just talking out of my ass.

[GTEASER]

Stock BPVs do not stay open under vacuum. The Synapse Synchronic does.

[James614]

OK. So it would actually be cheaper to go the DIY 1 way valve route and keep a standard BPV/BOV then.

[alienvictim]

Stock BPVs do not stay open under vacuum. The Synapse Synchronic does.

correction the synapse bov only stays open until MANIFOLD vacuum hits 0. in reality it takes not much to get your vacuum readings to hit 0.. however depending on the spool rate of a turbocharger you have that much time for the engine to starve until it can reciprocate by providing exhaust to the turbo...which it has to do by in-taking air.. this is a catch 22 of the turbocharger.

so the larger the turbo the slower the spool and so forth the more air the motor can utilize to induce spool through the use of a large bypass valve.

so no these do not even function similarly as the bypass system uses piping pressures alone to move the flap that allows air to go in and trap air from coming out of the intake tract or ic tract. and that can be literally a couple thousand rpm timespan on a large turbo built motor..

yeah you can run staging systems or rev matching ems systems.. but on a daily car thats retarted..

one last thing is that this also allows your car to behave and drive like an NA car all of the time.. with no drop in power from a dig. it was worth it to me.. very worth it.

I'm not that smart either, but a pool checkvalve? really?

I think you'll be very happy with more displacement, and that will help your spool tremendously. Also, what about twinscroll turbos? Kinugawa (spelling?) sells a conversion housing where you reuse your td05/6 as a twinscroll. Lastly, what about EWG's? Those will help spool from my reading.

I'm not totally discounting his work, I just really think if there were "shortcuts" to faster spool and more power, more people would have picked up on it by now.

yes really, its the only commercially available valve that is around 2-3 inches in diameter capable of handling the heat and pressure a turbocharged car can output.

while many things such as billet wheels, displacement, even air fuel ratios can affect spool. your still stuck with the fundamental enigma that the motor needs to at some point pull air through an unspooled turbo..

this compounded on top of those other things just means that your motor (however built) still waits for air to spool the turbo... for air.. which turns into exhaust.. you cannot build power or torque with nothing...its an impossibility. and also a major reason why smaller turbo chargers built power quicker but have a massively smaller threshold for over all power. but the fact is they utilize less exhaust to spool which makes them spool quickly..

with this system you can alleviate a lot of the waiting for the motor to inhale so it can move on to exhaling and moving the impeller and creating boost much faster.

the test car besides my tc.. was a built mitsubishi mirage with an evo engine and a 20g turbocharger attached.. through the logging software we found a drop of 700 pm.. and what he used was a bov t for the piping attached to an even cheaper white pool valve... it cost him 80 dollars to reduce spool by 700 rpms..

I've thought of this myself, I never knew anyone went through all the research and work to actually fit a working system onto a car.

While more displacement, higher compression, twin scroll, EWG's, etc all help spool time, IMO it's that much more awesome if you can add one more item into the mix to drop spool even more.

I'm VERY skeptical of claims of dropping spool by 700rpm. But there's so many dynamics and variables involved with that, I honestly couldn't even begin to try and argue it's validity. But the basic idea seems pretty solid. The compressor is not a very ideal oriface for air to pass through when it's not being actively pushed through by the wheel.

My one big question: Doesn't the OEM Subaru, as well as most other factory/OEM recirculating style bypass valves, already stay open under vacuum? This would achieve the exact same thing, excepting that the OEM BPV's typically used are very small and do not flow nearly enough to feed the engine without much restriction. Maybe I'm wrong about the operation of the OEM BPV's but I'm very certain I've read that they open under vacuum and that's why the car runs like total ass if you just vent it to atmosphere.

none of the bov/dvs even synapse stay totally open under vacuum. especially during a wide open throttle tap.. which is counter productive to the whole notion of this system. it closes during blips, rev matching, basically anytime a healthy amount of throttle is used.

also not many people are aware that a bov/bv is only there to keep the turbo from unspooling because of the backwash of air when the throttle is let off and the butterfly on the throttle body closes (ie surging).

so you are correct that the notion of a bov/dv being too small to feed any real air.. sure it can release a lot of pressurized air.. but flowing ambient atmospheric unpressurized air is another thing. and must be treated like a standard intake with the proper sized piping etc..

same reason why you would never use too small of a intake tubing on a turbo inlet.. or even an NA vehicle..

[alienvictim]

i have also been driving with this system for 2 years now with no failures or issues.

[just-rust]

Subscribed. This is very interesting!

[mittens]

This seems so simple its almost too good to be true. I'm constantly thinking of twin charging and different sized twin turbo setups, but all of those involve multiple valves, solenoids and ecu programming. I want to see it in action with a before and after comparison.

[alienvictim]

hahaha ok so heres the deal. i did get dyno info but because a dyno doesn't start recording until usually 2-2.5k and most dyno technicians do not start your chart until the appropriate gear for it like 3rd-5th you wont see any measurable benefit.. why? well if your not taking off during the time the turbo isnt spooled than you cannot measure the benefit from it. kind of like trying to record the magnitude of an earthquake after it happens. pointless.

because by that time (2-3k) the turbo has already begun to spool and the valve has become overwhelmed and shut. which defeats the purpose of measuring it.. because this was a drive-ability mod intended to get rid of loss in power when taking off from a dig. once this valve closes the system operates as normal. it just makes the turbo system operate at efficiency sooner. (although if your turbo only spools at 5k at the very end of your powerband yeah this will help a lot)

i guess this could be considered more of an early torque inducing mod rather than a final output of hp mod.. although spooling earlier can means more potential overall power.. but to be honest i haven't measured how much.. but i know that on my engine my torque curve was fat because of this.

if you could talk a dyno shop into letting you do a dig launch, or wot dig clutch drops.. but i doubt they will chance messing up their dyno to allow this.

this setup is definately beneficial to engines that normally pull a lot of air, or larger displacement engines looking to run smaller turbos to gain the same power levels faster. i mean i have done a lot of research and have seen some odd things people have to do to run either too small or too large of a turbo.. like making their rpm surge up and down (searching) to keep the turbo partially spooled so their engine wont die.. (interesting workaround but kind of annoying)

but this makes the turbo secondary.. and the engine runs better and even idles better with this.



this pic is of my dyno run at psi in portland last year. that spike at the beginning was my tires hopping on the dyno drum which made it lose load and have to catch up.

this was on a bone stock 2azfe block btw.

cant wait to install the hx40 turbo i got.. but i have to fix the act 4 puck clutch i murdered last week tuning lol

should be awesome.

[Legacy777]

Any chance you can post some pictures of the piping & valve setup you have, or perhaps draw a schematic?

Thanks

[alienvictim]

i think kimo posted the schematics i drew for my provisional i shared. they are in the 1st post. literally my turbo ic piping is normal with the exception of that branch off..i can do this because i run a blow through setup.. so no unmetered air enters the engine.

[Legacy777]

Forgive me if it's already stated in this thread, but what size turbo are you running and how long have you had this setup and valve in service?

[alienvictim]

its a td05hr from an evo 8 mr its a decently fast spooling turbo. but when i first installed it and tuned it it idled like garbage and responded like it had too restrictive of an intake attached to the engine. i have had 24 cars.. all of which were NA with the exception of this one. (since then i have driven a few lol) most if not all turbo cars have amazingly noticeable throttle issues that felt like garbage compared to an NA built motor until 3500-4krpm (even with a small turbo..lol)..

i tried altering my rev range raising my idle to 1100 and tuning the idle area so it would "search" keeping the turbo spooled, which helped a bit. because i tune my own car i tried running richer in the bottom range of afr (increases gas exhaust volume) helped slightly.. than got sick of it. remade my manifold about 3 times.. that helped slightly.. ported my turbo and head.. helped slightly.


got tired of the bs and thought about this. built a prototype 2 hours later and tested it in a theater parking lot. i have been using this setup for around 2+ years.. no problems.

heres a video a friend took of a drive we did.. i was trying to show the boost gauge but it was difficult to catch.

http://vimeo.com/62305473

[Legacy777]

Ok, thanks for sharing. I'll be curious to see if and how someone sets this valve up on their Legacy.

[alienvictim]

no worries, its fair game to use. i just hope it helps people enjoy their cars as much as i have enjoyed mine. also thank kimo if this works for you because i would never have bothered to post this on any forums so kudos to him as well.

[alienvictim]

just sharing what happened recently lol, i thought i trashed my transmission but turns out i just destroyed an act clutch.. after i built my motor i feel im getting some really good torque in conjunction with the bypass.

this had 800 miles on it.

[Legacy777]

That's not good! I'd contact ACT as that looks like a material defect or something. I wouldn't think it would break at the power levels you are at.