I have a vision.....

have a look for pictures of TTs car you can see how he did most of it, pretty sure he kept the inlets seperate, and used a common plenham over the throttle bodies

blower is overdriven for loads of grunt low down then gt30 IIRC takes over, it's sorting lag and the transition that's the tricky bit............oh and he has seperate intercoolers

 

Did Rob's example disengage the Supercharger?

All you can hear in the video he posted ages ago is a load of boost and the flap flapping about around the transition area .

 

Trendy Tramps motor:



The burgandy what...

 

ahh yes that's it the sta-press express, did you know they paint matched the colour to is ex lecturing outfit.....

used to be more pics on the AW tracksport site but can't get to them now, Tim Rallye probably has loads and is probably online more than the busy tramp as there's not many broad band park benches out there

 

Eatonjunky's design:

 

Cheers to mk1 driver for hosting my picture .

Rite, here is a quick explination of things.

The valve after the first intercooler is the throttle body. The turbo blows through it and the supercharger draws through it. The second valve is a supercharger bypass valve. This operates from the manifold pressure, my idea is to have a waste gate type acuatator connected to this. This will be set to start opening at say 15PSI. This will let air out of the manifold back into the supercharger inlet, this prevents the boost going silly high as the turbo comes in, the supercharger is gradually being phased out. This will stop the manifold going much over 15PSI of boost, if the manifold does go over this, its all due to the turbo. At this point the bypass valve would be fully open and the turbo would have all the load. The supercharger would simply be pumping air around its self. I think this design maybe capable of giving a smooth transfer from supercharger to turbo, because alot of the time they will be working together.

Please feel free to comment! I dunno if its been tried before, but I always like something new.

Danny

 

If your using a throttle body as a valve how will you make sure that it does'nt leak boost?

Anyone know if the bypass valve on the TSi is leak free.

I am trying the same sort of thing and need a bypass valve/throttle body to depressurise the supercharger. I can't seem to find one which will be leak free and solinod activated without the use PWM.

 

A throttle body will leak, but it wont be a massive amount. What you need is a ball valve if u dont want it leaking, I have seen one at work somewhere thinking about it. Mite borrow it to check it out and forget to take it back! Why do u want to use a seloniod? I have no idea what you are planning, but if something suddenly opens you are probabily going to feel it.

Danny

 

I was thinking ball valve for a decent seal, although they can take a fair amount of force to actuate - especially one large enough to flow a decent amount of air...

 

My supercharger is feeding the turbo, so i need the valve to bypass/depresurise the supercharger when the turbo takes over. As the boost will be equalised the transition should be smooth

Here is a pic of the TSi bypass valve which looks to me like some sort of fly by wire TB



I am assuming that this TB is machined very close to minimise leak.

Was also thing out the bypass valve that some eatons use but the bore is very small

 

The air will still be going through the charger wont it, so the bypass wont need to be mega large rite?

Am not to sure about the change over point to be honest, any air fed to the turbo from the supercharger is going to be compressed when under boost. When the turbo starts to spin up, I would expect it to further compress this, if you then open the bypass valve the turbo feed will change so the boost output will change. Thats what I think, although I dont really have any details of how your doing it. I am interested to kno the expect plan you have, as I havent really decided how I am going to do it yet.

Danny

 

I am using the same principal as the tsi engine in that the supercharger will feed the turbo. The boost generated by the supercharger will flow through the turbo and in doing so spool the turbo. However the turbo will not further compress the charge. I will need to match the volumetric output of the supercharger to the volumetric input of the turbo as not to surpress the turbo at high revs where the demand for air is much greater. At the moment my main problem as expected is the bypass valve. I have found a few but need to find out from the manufactures if they are going to be suitable for my application. I was thinking of using an exhaust cut-out however i dont think that it will be up to the job. I keep comming back to a Fly-By-Wire-TB and if i can get a dc controller then i could be in business.

 

I am still abit iffy on the theory, how are you going to know when the turbo is ready to take the load off the supercharger? If you open the supercharger bypass valve all at once, the feed of air to the turbo is going to change. This will have a massive effect on how the turbo performs as far as I can see... I dunno anything about the TSI, but I was thinking maybe some clever electronics are involved.

As for a suitable bypass valve, I found a 2" ball valve at work, its easy to open and close. Its ideal besides one big factor.... its rather heavy! I was thinking about using it as a throttle body but 2" is abit to small. Maybe I will use it for my bypass system, will see.

 

I've got maps for my supercharger and turbo. With these I will be able to determine the CFM's. For example if the supercharger has a ratio of 2.5:1 and is spinning at 7500 rpm the engine will be spinning at 3000 rpm. At this rpm the supercharger will produce 220 CFM. At 3000 rpm the turbo will be demanding 200 CFM so all is well. From the maps I will be able to see the change over point where the turbo starts demanding more than the supercharger can deliver. I will factor in a safety margin and by doing so will bypass the supercharger before it gets to the limit of the turbo. When the bypass valve opens the supercharger will depressurise and simultaneously open a channel of unrestricted filtered air. This channel needs to be big enough to allow the turbo to inhale. I’m looking for something between 2.5" & 3".

 

ok, I think I see how things are going to work now. Your going to wait until there is slight vacuum between the supercharger and the turbo, at this stage the turbo is using more air than the supercharger can supply so it is therefore safe to open the supercharger bypass valve.

Am not quite sure why you need such a large bypass valve though, the supercharger is going to be spinning, therefore air will be passing through it, so you already have a large percentage of what you need. The bypass valve can then supply the rest which is not going to be a great deal more. If at say 6000revs the turbo is doing 495CFM, the supercharger is going to be flowing 395CFM, so your only 100CFM short. I am sure a 2" valve is more than capable of supplying this. The supercharger will be taking the minimum power of all conditions when it has an unrestricted inlet and out let like this. Unless you have a clutched charger?

Danny

 

I've got a clutched M62 but not sure if i'll use the clutch. I,ve a few spare smaller pulleys that i might be able to use. I suppose i need to make a decision on the final plan

 

If you dont bother using a clutch and leave the supercharger spinning the bypass valve you need will not need to be as large. I think thats what I would do if I went for such a setup.