bypass valves

[hoshy]

Hi guys,

I'm try to find a bypass valve for the iS supercharger job. Just wondering if anybody knows companies that will see the original / uprated or adjustable bypass valves. I don't really know how they work. Can I set them to trigger at a certain map? Or maybe I can get an electronically controlled one triggered from the megasquirt - I guess that would be best.

Does anybody know where I can get details of the original cooper S setup?

Matt (appletree) what did you do for this?

[Ant]

you can buy the proper bypass unit from Eaton dude, around £180iirc no idea on availability though

Matt relocated the TB to the SC intake to get around this, possibly the best soloution if you want to duplicate his setup Ashley.

The Racercar 2.7 with Eaton M90 ran a single huuuge HKS BOV as main bypass with a smaller Bailey unit to unload the charger and force the plenum into vacuum earlier and open the HKS up.

HTH

[hoshy]

Cheers Ant.

Currently looking for a prince on the oem job (part 22 - http://www.realoem.com/bmw/showparts.do ... g=05&hl=26)

The OEM job for part load running. Then I thought a large-ish turbo BOV would do for the snap-throttle shut scenario.

From what I see they're all controlled by MAP I guess this is fixed - I can't find any sites that show spec of what manifold pressures they actuate at etc. Are there such things as electrically controlled valves? Perhaps something from central heating systems?

Not been able to find any uk suppliers for the eaton job - found I think the one you mean on an aussie site - http://www.capa.com.au/pics/eaton_bypass_valve.jpg

[Ant]

Easy fit is use the M60 shortnose pulley with the electro mag clutch setup, then you can boost when you want , indeed you'd use MS to give boost/TPS to control the whole assy

[hoshy]

Oh cool - so fitting the m60 electro clutch to the m45 is an option?

I'll investigate that route - cheers Ant.

[Ant]

TBH, I'd source the complete unit( merc breakers )

bigger, lower load and decreased charge temps to the M45 , more potential too.

[hoshy]

unfortunately I've just had Alex (turbo brown) make me up some brackets for the m45 so that's the route I've got to stick with for now mate.

[appletree]

Ya i used a bailey dump valve between the plenum and the S/C inlet, this was to even out the vacume between the inlet and the outlet of the charger when the throttle was shut and to allow a smooth power delivery when you opend the throttle again.

You could still easly put the throttle inlet side of the charger with alexs set up then just make a plate to pipe the outlet to the manifold with the throttle removed.

Iam going to be doing it this was on the MK2 and run a barrel type charger between the out let and the manifold as part of the inlet pipeing

[hoshy]

Does your dump valve (and dump valves in general) operate progressively then?

And how does it know what pressures to open and close at.

Sorry - I really don't know much about all of this and it's really hard to find information.

[Turbo-Brown]

You could have a try with the recirc dump valve from a TT or something. They're only £20 new or so.

Put the throttle before the charger, connect the valve between the throttle/charger and charger/engine, connect the signal line for the valve between the throttle/charger and voila, you should have one automatic charger bypass.

When the throttle's open there will be minimal vacuum between it and the charger so the charger will be fully loaded with the valve being shut.

For the price of it, might be worth a fiddle

[hoshy]

Cheers Alex. I've looked at lots of recirculating dump valves on flee-bay. I thought that many of them could help me out. I think it was yourself in the first place that told me they're manifold pressure controlled. Presumably an increase in vacuum in the manifold caused by the shutting of the butterfly and thus the dumping of excess pressure in a regular turbo system.

You're saying that I could control the valve from the vacuum created between the butterfly and s/c intake. I see how that would work nicely.

I'm still kinda bent on the initial tests being done with the throttle in place after the s/c though.

I suppose one question to ask myself is do I want it to hit progressively or am I happy for an open/close valve to kick in under certain conditions. I think on/off is fine.

Let's say for sake of argument I want it to kick in at 75kpa or higher. I could either program MS to switch on at that level and engage an electronic valve - I'd just need to find one.

Or, I'd need to find out at what pressure various dump valves operate at - I suspect they open at considerably lower pressures that I'd need. Perhaps 25kPa?

I think with that kind of system in place and the valve routed back in to the induction system for noise control I'd have sensible control of when I'm boosting and no danger of bent butterflys?

Or the above is a load of crap and I've missed something?

[hoshy]

Hmm - perhaps Autospeed has the answer: http://autospeed.com/cms/A_2188/article.html

[hoshy]

Ok - after some googling, emailing, ebaying and the autospeed article I turned up this little puppy:

http://cgi.ebay.co.uk/LARGE-BRASS-12v-E ... dZViewItem

If I hooked the above (or similar) in to MS and set MS to open (supply, or remove 12v) at a given MAP value and idle, then piped from the s/c intake to exit. Do you guys think that would provide adequate bypass? -- At least in principle.

I'm still looking for other 12v valves as that one is for water I think it might leak past and loose me some boost lol. Other than that the diameter of the intake seems more than enough given the BOVs I've looked at are on a 25mm diameter.

Any thoughts would be appreciated.

Cheers,
Ash

[appletree]

your worring to much about opening pressures! how offten do you drive just slighly on boost? its normaly on or off even in small amounts i'd say you'll find that theres a large difference in pressure so you dont need to be super accurate on open/closing pressures around the throttle position you start to get boost

With mine when the throttles shut everything behind the throttle is in a large amount of vacume, as soon as you crack the throttle it instanly goes positve and the valve shuts.

As long as it opens and shuts it will be fine, you can always put a larger spring in if you find it leaks or is speced with a very weak spring from standard

I actualy put the signal for the dump valve in the manifold so that when the manifold went in to positive pressure it would also help to push the valve shut!

I also installed the dump valve so that the suction from the inlet of the charger would suck the valve shut whilest being push shut from the otherside from the positve manifold pressure. if you imagine it the other way round the vacume could suck the valve open aswell as the pressure pushing the piston off the seat at the same time!

Its more a drivabilty thing, i took mine out as i though it might be leaking ( it wasnt) and now with it out at low speeds i get a slight gerk (like a worn diff) when slowing down with the throttle shut, not magor but still there.

Going to put it back in when i get a minute

[hoshy]

Cheers Matt - I think I've got what you're saying. For just cutting out the super charger when the throttle is shut I think you're right I don't need to worry about it.

How does your part-load/cruise system work - s/c fully disengaged?

I'm really starting to like this electronic valve idea. i've various outputs on MS I can look at using.

[appletree]

My charger is always ingaged so even at cruise its still pumping but in stead of pumping against a shut throttle or just venting to atmosphere the dump valve opens and makes a circuit between inlet and out let so there should only be a small pressure differencebetween either side meaning that as the charger is suckin in the pressurised air its just made so its under no load and sort of "free wheeling".

The only problem is the air gets hotter the more its beeten about but the engine is using sum all th time and as the chargers not working so hard to move the air as theres no restriction so its not as hot , swings and round abouts but you get the idea

[hoshy]

Yeap - that's exactly how I'd imagine how mine will work also. Although I'm thinking the electrical valve will do the job.

How does your valve setup know that you're cruising. Above I thought that you can use manifold vacuum to open the valve but even in a part throttle situation surely there would still be positive pressure in the manifold ?

[appletree]

Its purely on vacume, If i'm cruising a 80mph @3.5krpm with the throttle just cracked the chager is still putting out enough pressurised air ( and sucking in enough) to provide 8-10psi positive boost for the engine running at full chat at the same rpm so the dump valve will open and the inlet behind the throttle and the manifold will all go in to vacume or nearly zero.

Although i said the vacume signal for the dump valve is on the manifold it is actully as close as you can get to a runner on the manifold so its were the engine is in vacume to.

I would imagine it would be constatly adjusting as even when your cruising your using the throttle for going up slight inclines or easing off as some Tw@t in the midlle lane wont move over and the idiot in the out side lanes doing 71mph past her LOL

[Ant]

the off idle shunting is hard to get around, boost on the way up the revs , and again on the way back down, leads to an annoying "hang" on the transistion to idle.

the twin BOW is a great way around this but I cant help thinking the M60(65?) of a clk230 would be a better charger to use, elec clutch, bigger , less heat pump etc etc.

gets around all the issues in one swoop, kinda why MB went that route, they are declutched @ idle and come back in at 1400 rpms iirc, obv you'd the have the option of switching it out when not required, ie up to cruise on the m/way, declutch and lean out baby for 40+ mpg

Matt and his Dad did a great job with that install, but I think there were some hard lessons learned, and we have the opportuinty here with Ashley's conversion to address the issues head on and move to a "mk2" setup.

bigger better faster-more

would be a good exercise, Matt, Ashley and Paul( sheps) with 3 'charged M42's , all using different means to achieve the same goal.

[appletree]

Yes Ant your right thats why this time i've bought the M62 ( nearly there Ant LOL ), going to run it with the clutch, so it cuts out at idle in any map, an have it so i can switch it on/off and auto change the map at the same time.

Like you say it will be realy useful for motorway driving.

i averaged 38mpg with out it on a run and got 32mpg on the run to the pod last year but that was taking it realy stead with a the longer legged diff on.

i know eaton say the M45's good for 2.3 ltrs or so but i think that must be at like 2psi boost or something.

With the set up ive got now its well over speced Jag xkr 4.4 V8ltr? cooling rad, large water resivour, 12lpm pump and my laminova set up and the water still gets lute warm after a good thrash, so theres still to much heat for that huge rad to get rid off, the only thing i can think is that theres just to much heat in the first place!

Its fine in normal road driving , motorway driving but if you go for a out n out thrash keeping it high in the revs it start to get hotter, not to a dagerous level but i would a have thought it should be able to cope.

I normaly check it after ive pulled up home after a quick session and check it streight away so praps if i'd have driven round normaly for abit before i check it it would have chance to lose some of the heat.

[hoshy]

Ant - I really hear you - I am started to wish I'd not gone down the m45 route now either. I still think it's going to be awesome when it's done but Rotrex or m62 would have made for more interesting progression.

Still - I reckon there's some merit to the electronic bypass valve and I'm thinking about using water injection to to help me get the most out of the charger. So yes - all in all, quite a different set up to matt. And it will be nowhere near as nicely engineered

I suspect that with the right parameters (map / tps) MS will be able to give me a nice on/off idle transition and at least ease the load on cruise - not fully disengaged but I wonder how much difference there will be?

I got a price on the Goyen valve -- 40odd delivered...

Can either of you foresee any real problem going the electronic route??

[appletree]

Only problem i can see is that it will be ON/OFF and not progressional.

Are you fitting the water injection before or after the charger? Alot of the american drag cars run it before and it acts a a sort of seal between the rotors, some even have a single injector to ad fuel to cool the rotors and help the air/fuel mix sounds a bit dangerous to me!

[hoshy]

Yeah - I'm a little bothered about the on/off nature also. I just have to see how it works I guess.

I'm planning on running before the charger in exactly the way you mention yes, I was thinking of using an intensive wash tank for the water and seeing how just a small bit of added water will affect the intake temps and psi.

[appletree]

thats the best way! i used that same for my charge cooling res, holds loads of water and its easy to swop the washer jet pump round

Think there £12 odd from BM

[hoshy]

sweet

I'm heading down to see alex this afternoon to pick up the brackets,

Still loads to do though. Got to make up something to fit on to the exit of the charger, get some kind of intercooler - probably just anything that'll fit from eBay - then get the valve and lash it all together.

in the process I'll be losing power steering until I fudge up something for that too

[appletree]

Have you got a bracket to relocate the olternator yet, i need one but havent got round to it yet

You need to start a proper thread for your build or re-title this one and edit your first post abit, theres some realy useful information for anyone going the same route

chhep up the good work!

[hoshy]

I did get that sorted mate yes. Like you suggested I used the original bracket. Put some studs in the AC bracket holes, drilled out the bracket some because the holes don't line up quite right - only managed to get it mounted on to three holes but need to take off the whole assembly and rework it a little as it's started to come loose a bit. Also needed a new tensioner system because down that side of the block with the way I have the bracket there's very little room between the alternator body and the chassis. I think the other close shave was between the mounting lug of the alternator itself and the lower timing cover - I just took of a couple of mm with the bench grinder. Wiring was easy easy you'll get that no problem.

When I take off the assembly I'll get some pics up.

I think I started a thread some time back maybe I'll collect up all my s/c and MS thread and stick it all together in one thread.

[appletree]

Cheers pics would be good!