Supercharger&turbo charger

[pulsar gtr]

Ok, I thought I make a thread for this topic instead of hijacking the other thread lol

If having a big turbo on your ca18det is causing some serious lag, why not just add a supercharger to illiminate the lag at lower rpm and when it hits mid rpm, the supercharger will basically gets bypassed and the turbo at that time will have a full boost.

Ok, "iliketocrask" mentioned to have "pressure differential valve ", where can I get one of those and can I have it set up to work around 3K rpm then switch to the turbo.

Any inputs are welcome to discuss, I think we should make this topic very interesting as I wouldn't mind to attempt such a project.

Thank you,

PULSAR GTRRafi

[iliketocrash]

i don't believe a pressure differential valve necessarily shuts activates at a certain rpm. its more of when the turbo begins to build pressure higher than that of what the supercharger can build.

so this is my theory.lets say the super charger is running 5psi and the turbo is feeding the super. So you're driving the car... as the turbo builds up towards 5psi the pressure differential valve works to bleed air away from the super and directly to the intake mani. by the time the turbo builds an equal or greater 5-6 psi then the air is completely routed away from the supercharger and the supercharger is then shut off.

what do you guys think? i don't know exactly what a pressure differential valve does or where to get one but this is the best way i can think to do this. so i figure i can use two stepper motors, probably a map sensor or two and a few butterfly valve type pieces.

[Ace 2.0]

a buddy if mine wants to do this to his CRX si keep the info comin!

[float_6969]

The valve would just work like a wastegate actuator. As it starts to read pressure on the suction side of the s/c, it would direct flow past the s/c. It would simply be a feedback loop. Then you'd use a pressure sensor or maybe a switch on the valve to kill the clutch to the s/c and turn it off.

[iliketocrash]

exactly. the main thing is actually rigging up a working system... for as little money as possible. lol

[redamnavit]

The plan seems to be to have the turbo feed the supercharger, correct? I seem to recall some concerns with people twincharging MK1 MR2 that feeding pressurized air into the supercharger would stress the oil seals. Whether this is a serious concern I'm not sure. In general though, try looking at the twincharged setups for AW11 MR2s; they might give you some ideas for an approach.

On a side note, I've seen one guy fit a stock CA18DET exhaust manifold to his 4AGE with some filing of the bolt holes. Strange bedfellows...

[iliketocrash]

i don't see it being a problem as long as your not feeding the super higher pressure than what its pushing. nissan made a car with this exact setup and it seems to work fine.

[pulsar gtr]

So, I found an rb26dett a while back on the net, with twinturbo and supercharger here is the linkhttp://www.freewebs.com/pulsar...e.htm

What do you think of this kind of set up.Personally I think it is easy, just have to install a bigger pulley on the super charger if required so when the engine is reving hight it doesn't have to work very hard, as at mid or higer rpm the turbos will do the work

PULSAR GTR

Rafi

[redamnavit]

i don't see it being a problem as long as your not feeding the super higher pressure than what its pushing. nissan made a car with this exact setup and it seems to work fine.

So you'll divert around the SC when the turbo hits, say 5-6psi? Or use a clutched SC and let it disengage around there?

Are you referring to the MA09ERT? That's a neat little engine. One of those in an Ariel Atom or something similar would be a lot of fun.

[Myetball]

I've seen some Z32's using NO2 to overcome turbo lag. Program your system to cut off the NO2 at the RPMs where your turbo kicks in.

Much simpler than a supercharger but keeping the bottle full may get tiresome.....and expensive in the long run.

[iliketocrash]

exactly, Myetball.

redamnavit: not so simple. the idea is to not instantly go from one to another but to smoothly divert as in start off by bleeding off pressure as the turbo reaches the output of the SC and then when the air is fully diverted, then the SC is shut off via electronic clutch.

[pulsar gtr]

Hi know ryan mentioned about the MR2 supercharger that it has a clutch on it, I think that is one of the best ones due to that it got a clutch for such an applicaton.

Ryan, how sure are you about the mr2 supercharge that it got a clutch on it?

Thanks,

PULSAR GTR

[float_6969]

I'm 100% sure it has a clutch on it. You'll still have to figure out some way to hook up a bypass so the transition is linear, but I still think it would be the best bet. It should be eaiser/cheaper to get ahold of. The problem with running it like they did in the skyline setup, is that I don't think the transition would be linear.

[limecorrado]

How do you calculate the amount of boost it would produce?

Say the turbo puts 10 Psi And the Supercharger puts out 8 Psi

Is your total boost to the engine 18 Psi?

Oh and i own 2 of the eaton superchargers with the Clutch On them they Work really well.I Have wanted to Do a Twin charge Setup fo sometime using one.

[iliketocrash]

no. you don't add them together. you just use the supercharger to reduce lag.

[float_6969]

The problem with a twin charger setup is that the boost from a supercharger is linear (generally, not all superchargers are the same), and the boost from a turbo charger isn't. Turbo's were originally designed to be used on engines that don't vary speed like a car does. The were actually first used on things like airplanes and tanks. Those generally run at a constant rpm. Because of the sheer design of a turbo, it is only effecient at a certain rpm range. That is the reason that you have to get a certain amount of exhaust flow before you get power and why too much overheats the air charge and effeciency drops. Superchargers still have the same problem, but the rate at which it happens is much more linear and predictable. The problem with mating the two is to try and match the superchargers boost curve and the turbocharges boost curve so that the transition from one to the other is smooth. This is a hard task to acheive and part of the reason that it's not done sucessfully more often.

[float_6969]

This is more about that MA09ERT motor that came in the Nissan March from 89-92...http://www.autospeed.com.au/cm...=2216

[redamnavit]

redamnavit: not so simple. the idea is to not instantly go from one to another but to smoothly divert as in start off by bleeding off pressure as the turbo reaches the output of the SC and then when the air is fully diverted, then the SC is shut off via electronic clutch.

I have a feeling this will get shot down but have you considered an electric supercharger? You could use the signal from a boost sensor on the turbo to reduce voltage to the electric SC in relation to rising turbo pressure. Wire in a switch to turn the thing off if you're crusing in traffic so you don't kill your battery.

[iliketocrash]

what? its the same concept as a BOV or wastegate. Both gradually open . They don't just instantly pop open at a given point. What do you mean electric supercharger? i hope you don't mean those little hair driers they sell on ebay that go on the end of your intake just after the cone filter.

There's no reason for any of this to get shot down because Nissan makes a car with a system that does exactly this and HKS even made a twincharger kit for the toyota mr2 that did this and that was probably 10 years ago or more. I think HKS even made a custom twincharged integra just last year as a matter of fact. This is all very possible. It just needs to be figured out because for some reason the details on this system should be public knowledge but it doesn't appear to be. I'm gonna keep trying though. It'll work... oh yeah, it'll work.

[pulsar gtr]

Ok,

So, I will need an Mr2 supercharger to experiement with it, any one got one or know where to get one, and If I get one what should I be looking for to make sure it is good, as I haven't worked with superchargers yetThanks,

PULSAR GTR

[redamnavit]

what? its the same concept as a BOV or wastegate. Both gradually open . They don't just instantly pop open at a given point. What do you mean electric supercharger? i hope you don't mean those little hair driers they sell on ebay that go on the end of your intake just after the cone filter.

No, I mean similar to one of these:

http://www.boosthead.com/home.php

Its basically a few starter motors geared together to drive a positive displacement supercharger. In addition to varying the voltage to it as boost increases, you'd probably want a switch based on throttle position so the SC is off when the throttle is closed.

So, I will need an Mr2 supercharger to experiement with it, any one got one or know where to get one, and If I get one what should I be looking for to make sure it is good, as I haven't worked with superchargers yet

Try:

http://www.mr2oc.com/

They've got a parts section and a good MK1 community. Someone should be able to help you out.

[pulsar gtr]

Thanks, I will check out those links,

PULSAR GTRRafi

[NeedCAforS13]

hott (two t's for extra hotness)



Sean

[float_6969]

Sean is Ghey, with an 'h' 'e' for extra Gayness...

[fraz]

Those toyota superchargers are positive displacement type. There are 2 types, SC12 which is 1.2L per revolution and SC14 which is 1.4They both have electronic clutch. You just feed the wire 12v to turn it on.

For example, (i have actually seen this setup) You have a toyota 4agze with the larger SC14 bolted to it and geared so you have 14.5psi (1 bar) all the time.This means you are doubling the air pressure because the air pressure going into the blower is 0psi and there is 14.5 psi on the other side. (You are doubling the air pressure)If you then go and say put a dirty big turbo on it, blowing into the supercharger, you will still haev your 14.5 psi at the engine Untill the turbo spools up.

Then say, you have 14.5 psi at the intake to the blower whith the turbo spooled up, you will have 29psi at the outlet of the blower (take a few psi off for losses) or say 26psi.

Think about it

I saw this setup on a 4agze track car. The guy that built it was running 35psi at full boost and about 16 from 2000rpm. He was running a turbo->cooler->blower->cooler->engine, but removed the first cooler as it took too much space and was unnecessary.

Basically you take your boost graph and move the line up by whatever yout running at the blower, only once the turbo comes in, it wont add your blower boost, it will multiply the turbo boost by whatever ratio yuor blower has.

Sorry if this is a bit all over the place, but you should get the picture

[iliketocrash]

that can't be right. if the SC is set to compress 14.5psi of air and the turbo is set to compress 14.5psi of air then it stays 14.5psi because the engine is a "closed" system, i guess you can call it that, and the engine can only ingest so much air due to displacement. so each is compressing 14.5psi of the same quantity of air, correct? If both chargers are compressing the same amount of air at the same pressure then it can't be recompressed. I dunno how to explain it. Basically i see it as if the turbo is pusing 14.5psi and the SC is pushing 14.5psi then because the turbo is feeding the SC the same amount of air compressed at the same pressure then its only taking load of the SC because the SC doesn't have to fight the air to compress it because it's already compressed. It would just be free-wheeling. I just think that if the SC could recompress the air that is fed to it by the turbo then there would be no point to turning the super off or routeing around it.

This is just how i see things. I'm no physics major or anything. Its just how i see it. So please don't flame if by chance someone here is a physics professor and thinks i'm an amazing stupid retard. Just correct me

[cortina-mk1]

lancia delta S4 have a supercharger and turbo fitted to their Group B rally car very successfullysupercharger would turn off when the turbo was on boost(i hope i got the right model

[fraz]

(All boost pressures are assumed as if there are no losses)

Ok, say your engine is a 2L. It will consume 1L of air in 1 revolution with no boost.If you have a SC14 hooked up, and the pulley ratio at 1:1, it will pump 1.4L per revolution, which means you are going to get boost. Around 5psi which is 33% more air than if it was n/a

This means that your engine will get 1.4L of air instead of 1L of air.If you have a turbo on the front of the blower, and it is pressurising the air, say 7psi, this means that when the blower would normally draw 1.4L of air, it is infact drawing 2.1L of air.

Now, if you go and stuff this into your engine which is drawing 1L per revolution, you will have 16psi at the intake.

So what i mean, is that you can have a larger turbo on your engine that would not make any boost till say 5K, but you can have 10psi from idle to 5K, then the boost would go up pretty savagley after that.You cant be crazy of course, but you get what i mean.

If its still a bit messy, ill do a diagram tomorrow for ya

[undertaker]

some racing trucks and the like use compound turbos to generate high boost pressures. on the ones I have seen the exhaust from one turbo feeds the other turbo and the compressor of that turbo feeds the first turbo, its looks cool!

I am lucky enough to have driven a Micra Superturbo, that was a cool little car but the chassis let it down.

[r34 gtr]

screw it. just put a nasty big blower on it and call it a day. if its good enough for john force, then by god its good enough for the rest of us.

john force, a great american hero, built this country brick by brick. with his BARE HANDS. he is my god. sure he may be completely illiterate, sure he may not ever bathe, but with reaction times like that, who cares?!

i had a dream i converted my car over to run on dual 45mm webers last night. it was awesome.

oh and ryan, you totally stole the "ghey" thing from me. poser.

- tim