4agze Twincharger Conversions

[smeak123]

hi new here,

will a4agze go in a hilux 89 has anyone ever seen it done need help

[twincharger]

HI there,

 

I think you're overcomplicating the bypass valves... Remember the supercharger and the turbo are sequential, so no matter when you turn the supercharger off, you will lose at least 1/2 your boost, no matter of the turbo is doing. Mine is programmed to turn off at 7500, but that's more of a safety/rev limiter precaution than trying to get it out of the way. It's also controlled by throttle position, so if you want to run turbo-only, then just use less than 50% throttle. It does turn off between shifts, but so far that has not been a problem.

 

I use no ABV (removed it), and my supercharger bypass valve is a dumb flapper. No electronic controls on it at all.

 

The supercharger shouldn't mind recieving hot air from the turbo, because it won't be for much time, so there isn't much chance to heat up the supercharger lobes, and the turbo does not have to supply huge amounts of boost, so the air should not be too hot. Use 2 intercoolers if you can, but in my case, there was no room.

 

My first attempt had the throttle plate before the turbo and before the supercharger and before the intercooler. There was a tiny bit of throttle lag, it made kind of a *pop* sound when you opened the throttle and air filled the intercooler and pipes. Yes it could take a while to get back down to idle, but fortunately, the TPS has an 'idl' wire that makes the ECU cut fuel when rpm>2500 and the throttle position switch is closed.

 

I have done both turbo>supercharger and supercharger>turbo. I don't have a preference, but move the throttle plate close to the intake valves.

 

Anyway the twincharged 20v is installed and running. I just buttoned up all the computers last weekend, and am cleaning up underhood wiring. I was using the deleted supercharger ABV as a blowoff valve, but today I got a Greddy-clone blowoff valve, which will make me change some other plumbing to make it fit. It now runs COP ignition, no EDIS parts. It's coming along...

 

Twincharger

 

http://www.geocities.com/twincharger/

[philbey]

A better option than the Roots blowers are the Lysholm twin screw suberchargers, which come on such cool engnes as Mazda's 2.3L V6 miller cycle. This particular SC is made under licence by IHI and they are a real nice peice of kit. they're much more efficient and over come many of the short commings of roots style blowers. They're (the one on the Mazda miller cycle engine is) also of a larger displacement then the toyota SC's. Meaning you can run it at a lower speed (less drag/heat) to pump the same amount of air.

 

Interesting you should bring those mazda blowers into the conversation Jordan. Some of you may know Allmaz Mazda wreckers in Melbourne, the dude that runs it is a champ. Anyhow, he had one of those blowers on the bench when I went in there last and I asked if he'd sell it.

 

Long story short he said to steer well clear of them, he said they are a dog of a thing and they constantly give trouble.

 

thats coming from a guy whos dealt with a lot of them too.

[Jason]

IMO the only design to use that would be beneficial would be the VW.

 

"The supercharger shouldn't mind recieving hot air from the turbo, because it won't be for much time, so there isn't much chance to heat up the supercharger lobes, and the turbo does not have to supply huge amounts of boost, so the air should not be too hot. Use 2 intercoolers if you can, but in my case, there was no room."

 

Define 'much time'

 

I though the idea of twin charging is for the S/C to take the slack until the turbo starts boosting? So if you turn it off it shouldn't matter. because the turbo SHOULD have matched and be exceeding the flow of the S/C. If not the system is wasting energy. Then again the restrction of the S/C are reduced becuse it no longer has to compress air. But its still heating it up.... So even if it is 'idling' at say 15psi it is still wasting energy by simply moving and add that to the fact its heating the air up for no reason other than just to be on.

 

:y:

 

not taking into consideration how much strain the S/C clutch is put under if it constaly being turned on and off at speed* (as in i really don't know)

Edited October 15, 2007 by Jason

[AE25]

Yeah easy, but highly restrictive. I always thought the idea of twin charging was to be able to benefit from both the positives that most supercharger and turbo charger owners love to pledge as why their kind of boost is better - instant boost of the S/C and and top end power without mechanical load on the crank of the turbocharger.

my thoughts on sc12 being 'restrictive' in a twincharge setup... yes when sc is before the turbo.. in which a bypass is required.

In 4agze, i've seen sc12 flow enough for around 200rwhp.. 210 at the most on a 4age, using a bigger crank pulley to get 14psi or whatever the limit is before heat destroys the lobe coating. i've also seen improvements by replacing the std 4agze intake manifold (with the crazy dog leg #1 runner) for an equal length straight runner intake. (remember making an engine flow requires all links in the chain to be able to flow the same amount), the charger may not always be the restriction. But the main limiting factor of the sc12 roots charger is the heat generated at higher pressure ratio's.

Just remember the roots charger is an air pump. it does not compress air within the charger like a lysholm twinscrew charger. it only compresses air when there is a restriction after it. therefore it works on a pressure ratio. the higher the pressure ratio before and after the charger.. the more work it is doing.. and the higher the boost and outlet temperature is. if both pressures are equal either side of the roots, then there's little or no load on the belt.. if atmospheric pressure either side.. then it's free wheeling. if equal amount of vacuum on either side (4agze at idle with ABV open) and it's free wheeling. 10psi on either side.. and its freewheeling. this is because it has a ZERO pressure ratio in these conditions. all it is doing is passing a volume of air from one side of the charger to the other.

 

how this is relevant to being 'restrictive'... if a turbo is supplying 15psi air into a compound system and the roots sc is multiplying this by it's pressure ratio.. say 1.4, then with other influences like heat ignored, you'd be getting 27psi out. 30psi absolute x 1.4 - 15psi absolute = 27.

now if the actual measured pressure was around this calculated figure (it's not going to be exact due to other influences) then the charger can't be 'restrictive'. it would only become restrictive if there is less pressure after the charger than before it. or possibly if the pipes entering and exiting the charger were too small to flow the volume required.

 

back to the heat thing.. this is an efficiency issue, where at a certain pressure being produced, it creates too much heat... the heat is induced into the air from compressing it, and also made worse from the large lobe surface area conducting that heat into the lobes and passing it onto the incoming charge. friction from air passing thru the lobes could possibly be another heat creator all working together to cook coatings.. prolonged boost will likely cause damage rather than short bursts.

But, say we give the sc12 some cooled positive pressure to suck on from a turbo, it then compresses this more due to it moving more air than the engine inhales, but doesn't have to compress it as much to make the same pressure as before, therefor not heating it as much... this means that it can now flow MORE air than it would by itself without melting the coatings off.. the incoming air temperature would have an affect on this, so the colder, the better.

and why, even tho people may say a supercharger is inefficient... is beneficial in a compound system because the sc can provide more boost and make more ultimate power than the turbo alone. a turbo has an efficiency zone as well.. and beyond it's optimal efficiency it creates more heat, and has more back pressure in the exhaust manifold.

The main point here is, the sc is NOT restrictive in a compound boost setup if the charger increases boost.

 

My thoughts on mechanical loading of the SC belt..

when charger is running and has pressure after it, there will be load on the belt, same for if there's vacuum before it and atmospheric pressure after it. (set it up on a bench with an electric drill driving it, cover intake pipe and see that drill shit itself!). BUT, how much load does the belt really see if there is equal air pressure before and after the charger?? or rather, if there is a bypass valve that opens allowing air to recirculate or equalise, even at 5000rpm and higher. obviously there will be some acceleration lag due to inertia, like having a heavier flywheel fitted, but how much parasitic drag is there actually??? doing 200k down the back straight of a racetrack.. will you even notice an SC free spinning once the bypass valve opens? your acceleration rate wont be that fast that inertia is an issue (depends on application of course), but the parasitic drag of a loaded belt will affect hp and top speed. so i think this calls for a test run to see how much actual power is taken from the engine from a free spinning charger, a run with supercharger switched off at full boost from the turbo, and one with supercharger kept on with turbo at full boost (bypass valve open).

So who's got a twincharger they want to dyno or do top-speed runs in aye! aye aye!

Edited April 27, 2010 by AE25

[AE25]

hmm interesting about the mazda/IHI blower!

 

hey twincharger :wink:

whats your name BTW. good to get your experience in this thread!

I'm very curious how well the 'one way' valve works. have you ever checked to see when it opens and if it opens? the reason i ask is this.. you say you have turbo blowing into sc with a one way valve to bypass the sc when turbo comes on boost, but i see a reason why it may not open and that is, the sc will be providing boost which will hold the valve shut, then turbo comes on boost.. and say at one point in time theres now 1psi in front of the valve and theres 1psi blowing into the charger which compounds and always stays higher in pressure after the charger than before it and also the valve.. so the valve is always held shut? could this be the case?

or if the valve is plumbed in far enough ahead of the sc that there is a delay in pressure rise before the charger than before the valve so that the pressure behind the valve is also delayed creating enough difference to force it open?

could there be a combination of both where.. upon getting onto boost quickly it'll force the valve open, but a slow rise in boost will always keep the vavle shut?

or am i just getting a wee bit too theoretical now heh. :P i like to throw theories around in the hope i'll understand whats actually happening when i get it running should it all go wrong!

cheers

[AE25]

onto my own wee project. was originally considering a non intercooled SC setup so that the sc was a simple bypass in the pipe between intercooler and engine. i was hoping that a low 8.0:1 compression ratio and water injection at higher temps would be sufficient to stop any chance of detonation on a lowly 10psi from the SC.

my current 3tgte ct20 in the ke70 coupe creeps up to 13psi non intercooled.. and i know how damn hot the intake pipe gets just from heat soak alone.. thankyou toyota for 7.8:1 compression and 10:1 a/f haha. hmm wander how quick the intake air temperature sensor is to read the constantly changing air temps! this could be an issue so a fully intercooled system always going to be better

 

original planned like this:

 

 

after having a good look at the piping of that twincharged evo9 in Colorado with a friend luke (also looking into twincharging, but with an sr20ve 160J SSS coupe) we figured a way to intercool both chargers without too much complication or clutter in the engine bay. by entering the intercooler from two ends, and all piping can be kept low for appearance sake :P pipe from turbo to supercharger tucked away behind bottom of radiator. This system has longish pipes before the supercharger but shortest possible piping after which should help with supercharger response, and who cares about turbo lag as we're already on boost woot!

 

 

on the water cooling side of things.. the 20v water pump could be used on a supercharged 20v, but with modified water intake pipe of course. I'm wanting to get rid of any rubber hoses if i can just for reliability sake. especially ones hidden behind supercharger! so the 16v 4age water pump and steel intake pipe suits my wants, BUT the intake pipe hits the supercharger if from an n/a 4age, whereas the supercharger one obviously doesn't. (pipe is bent differently). that in mind, rather than source gze parts which could be a bit more expensive to replace later on.. have opted to make stainless intake pipe and just a redtop 16v water pump.. something common woohoo

Edited November 1, 2007 by AE25

[Jordan]

Sounds like your keen to get it going but remember this, only 3 cars from factory have ever been twincharged

 

1: Lancia Delta S4 (the group B rally monster, this had super/turbo changeover issues, but was better at low revs than the compitition)

2: Nissan's "SurperTurbo" notreally a performance car, done for efficiency?

3: VW Golf TSi much the same as the nissan setup, doesn't make much power, done for efficiency?

 

This means that while it is technically possible, it's not really worth the effort. One way/butterfly valves opperated by diafram vacuum lines are problematic and annoying to set up, especially at change overpoints. The easyest solution is this

 

air filter

largish turbo

intercooler and bov

supercharger

waterinjection or aftercooler + BOV

Throttle plate(s)

 

THere's no change over just more boost rocks up.

 

Ask yourself this though why am I doing this?

1: Academic exercise, proof of concept, because I can

2: Hills thrasher, traffic light hero, fast street car

3: Circuit

4: drags

5: Rally monster

 

Of all these possible questions only option 1: is a valid reason, and here's why.

 

2: for stret car, the instant respone of a surper charger is all you'll ever need in a light weight car, the speed limit is 60km/h and 110km/h. In the hills out of the corner response is important, but topend speed isn't. It's moer about breaks and handeling. so for this the supercharger or modest turbo alone are fine

 

3: Here is where big power matters and shows up when you don't have it. A large (300RWkW on a 4AGE) turbo works on the track as you can keep the engine on the boil (+4500RPM) so you're never dropping down into the region where the SC would be on. thus the point of a twincharger is lost.

 

4: Club level drag racing is all abot being consistant, not the best time. Simplisity rules the drag strip, in a dial your own drag race you will never beat a stock late model auto camery, as it'll always run the same time. For most sonsistant results a striaght SC setup works best, as it's less likey to bog down off the line.

 

5: you don't have enough money, and with anti-lag on turbos, twincahrging isn't worth the effort.

 

Cheers

jordan

[Boost+k]

i think it doesnt need to be that complecated either, i think a turbo blowing through a intercooler through the supercharger with a small amount of water injected at the intake of the supercharger to cool the lobes would be good enough? whenever the car is moving it should be getting fed fairly cold air from the cooler anyway?

even maybe using a water-to-air cooler to make sure its always cold?

[Jason]

every car sucks in the same abinets air temp...., thats not enough to cool a single turno or sc steup let alone twin charge

 

watere air IC get saturated

Edited November 7, 2007 by Jason

[machg]

Another idea relating to induction design (if you have the room): operate the supercharger and turbo completely independently of each other. Run a blow-off valve on the supercharger side. On the intake plenum, mount a throttle body on each end, with two stroke style reed valve after the throttle bodies on both ends. On the turbo end have a blow off valve set up to work in reverse. How it could work is at low rpm, the supercharger will make more boost than the turbo, so on the supercharger side the blow off valve is closed, and the air is blowing into the plenum on the supercharger side. The turbo side has the blow off valve open, allowing it to build boost. The boost pressure is trapped in the plenum by the reed valve on the turbo end.

 

At high rpm (or whenever turbo boost > supercharger boost) the supercharger blow off valve opens venting boost, the turbo blow off closes, pressurising the turbo induction side allowing boost to enter on turbo side of plenum, the reed valve on supercharger side closes trapping boost.

 

The problems would be having to rig up cables for two throttle bodies, room and flow restrictions caused by the reed valves.

 

You could do the same thing with a "2 into 1" pipe with an electronically controlled vane valve, and single throttle body. Actually, maybe a vane valve, lightly sprung to be in the middle (half open half closed on both sides) would do the trick.

Edited November 7, 2007 by machg

[Jordan]

They're very good points.

 

W/A intercoolers are really only good in these 3 applications

1: drag racing

2: in an MR car where a front mount means uber lag, + you can have a monster heat exchanger at the front, to negate much of the heat soak :evil:

3: in a boat, when you've got the ocean or the river (what's left of it) at your finger tips, why not use it.

 

With twin charging you really need 2 air charge coolers, generally a true intercooler (between the power adders) and an after cooler.

 

with anti-lag avaliable for turbos, its just not worth the effort. Or with the money saved on a single turbo setup you could spend the rest of your budget on a better quality turbo.

 

Cheers

Jordan

[Rolla__Boy]

Interesting

[Jordan]

hate to say it but that's great value

 

and totally awsome

 

jordan

Edited November 11, 2007 by Jordan

[Jono]

http://www.autospeed.com/cms/A_1850/articl...?popularArticle

 

 

autospeed article on twincharged ae92