sc14 meets m30!??

[rowanhol 0]

so ive decided to do it, just bough a sc14 supercharger to slap on my 535.. i know it's only small and it won't run high boost but that suits me fine(don't want to undertake extensive engine mods).

I have many questions and need good sound advice, try not to criticise. i'll try to keep it to a couple of questions at a time

I'm expecting 4-6psi, going to run a small front mount intercooler, afm before superchager, either a recirculating BOV or a CBV, rising rate fuel pressure reg.

1: BOV or compressor bypass valve? basicly bov opens when still under boost when throttle body closes(gear shifts etc) but stays closed in every other situation

CBV is open during idle(small amount of boost from supercharger and vacum from inlet manifold hold it open) and closes as you stomp the right pedal..in theory can be set to fully close at say 3/4 throttle giving max boost. so still quite driveable around town and on open road until you give it heaps.

I assume both systems work the same way but cbv has a very soft spring so that it stays open at idle whereas bov has hard spring holding it closed. so could i trim and stretch the spring in a bov to work the same way? or are they quite different?

I myte run an in dash switch for the clutch on the supercharger so i can turn it off on the open road so maybe i just want a system that will vent at idle and during closing of the throttle body but fully close and build boost at around 1500rpm..

also whats the deal with diaghram and piston bov's? ssqv?? whats up with all the different types,what one do i want?

remember i'm going to plumb it back to intake between afm and supercharger

2:how could i remotely mount the oil filter since it's perfectly in the way of where i want to mount the supercharger

anyone done this before?

[hybrid 1043]

If its a belt driven SC unit ... this negates the use of a BOV.

The oil cooler would sit just in front of the radiator.

Have a look at how us e46 fellas do it.

http://www.e46psi.com/

Great site for all SC questions .. as this form of F/I is more popular in the states.

[rowanhol 0]

If its a belt driven SC unit ... this negates the use of a BOV.

The oil cooler would sit just in front of the radiator.

a supercharger is still spinning at very high rpm when throttle body is closed though,the engine doesn't drop from redline to idle immediately it needs some form of vent to stop boost spiking in the intake tubes, also a supercharger tends to build boost at idle more than a turbo and puts a fair amount of load on the system. im pretty sure i can use a piston style bov and cut the spring down and stretch it..making it vent at idle and close at low boost when the TB is opening.

did you mean oil filter or cooler? i need to relocate the filter,damn

[topcat 11]

dont know what you need to run a low boost supercharger set up.

but as for the oil filter housing;

get or check up on the 750 setup.it is a remote.they have the oil filter bolted up against the left gaurd,rather tidy

[rowanhol 0]

managed to find an interesting article on bmwe34.net about oil canisters, Racing King used to make an adapter plate that bolts up to the block and runs a couple of hoses to a remote oil canister. have emaild them to see if the kit is still available.not sure if kit uses 535 canister or if you need an aftermarket unit though..could be pricy.could look hell cool also haha

alternatively any one have a remote canister from a 750? or something similar?

[hybrid 1043]

a supercharger is still spinning at very high rpm when throttle body is closed though,the engine doesn't drop from redline to idle immediately it needs some form of vent to stop boost spiking in the intake tubes, also a supercharger tends to build boost at idle more than a turbo and puts a fair amount of load on the system. im pretty sure i can use a piston style bov and cut the spring down and stretch it..making it vent at idle and close at low boost when the TB is opening.

Did you mean oil filter or cooler? i need to relocate the filter,damn

cooler

Sweet .. I looked into all this about two years a go ... was gonna cost some serious $$$ .. but the main cost seemed to be around the softwaring of the ECU .. all the RnD costs (for an e46) in removing all the errors from the system diag's and adjusting the fuel maps (amoung other things)

Most S/C units have a automatic disengage anything below 1k rpm, have a look into it as its fairly important.

Around the BOV ... Your thinking about the intake pressure buildup. Which would normally slow a turbo charger as the exhuast manifold side is no longer providing positive pressure thus spinning the turbo the intake pressure side starts pushing back on the turbo causing it to slow. As your supercharger is belt driven from the engine, this wont be a problem as the, especially at low boost. The torque of the engine is far greater than a senstive the turbo setup. You will also find it hard to get the blow off sound your after at low boost with valve spring rates are really designed for higher PSI at lower RPM. you would only be getting that sort of thing happening at the highest of RPMs when your boost pressure is at its highest. The boost pressure is controlled as you probably know is controlled from the new pully wheel you will be installing. smaller wheel = more S/C RPM = more boost.

Anyways good luck with it! .. you will certainly be blazing trails around these parts.

[rowanhol 0]

a supercharger still needs some form of release valve,trust me ive looked into it a hell of alot, i'm not after a pshhhh sound, i'd rather die of aids then have my car sneeze down the road, plus i'tl be set up plumback style as my afm would have alredy measured the air,so shouldn't be able to hear it releasing pressure..hopefully

the purpose of a bov for this setup is similar to a turbo, a supercharger spinning at 10,000 rpm is pushing alot of air, all of a sudden the throttle body closes(when changing gears etc) there is a massive spike in pressure as the supercharger/ engine keep reving highly for a second or so. all that excess air has nowhere to go except back into the supercharger trying to stall it causing it to slip on the belt or damage the unit.. or blow off hoses

I also understand a bov is generally only adjustable to release between 10-25psi which my setup will never get too, hence why im asking if i'ts easy enough to trim and stretch the spring making it release at lower boost and under idle vacum.

my unit has an electro magnetic clutch so have two options

1. have a microswitch connected to the throttle so it engages in at a certain point through the accelerator travel, although i dont think you can let it kick in at too higher revs.

2. have a switch in-dash and turn it on when i want some extra power and leave it off for open road cruising etc- with this setup i need a bov or cbv to release at idle when the supercharger is engaged.

[Surge 1]

If you are looking at a pressure release valve, try a shop that specialises in compressed air equipment. They will have something suitable to your needs. Tap into manifold.. and you're away.

With a supercharger, Would an option be - to obtain low boost to keep the valve (as per above) set at 4-6psi, and continually vent? Thus elliminating the need to have it controlled (on/off) like you are saying?

[rowanhol 0]

found some nice machined alloy replicas of the plastic bosh compressor bypass valve on ebay, should be exactly what i'm after, stays open under engine vacum and closes as soon as positive pressure is present in the inlet manifold..ace

not 100% sure on what you mean but my setup will run roughly 4-6psi max, estimated with max revs the supercharger can handle. myte be able to leave the supercharger constantly engaged with this bypass valve as it will only close and build boost when you stomp your right foot.basicly freewheeling at idle and cruising.

i just didnt want to use bucket loads of gas when cruising at constant speed on the open road

[Jonty m50e30 0]

Gidday I am really interested in this thread, with me not knowing alot about S/Cing are you confident that the SC14 is up to the task I have heard mixed reviews about using this blower, and it comes from a fairly small engine compared to your 3.5l the reason I ask is that I was looking pretty hard at putting one on the m50 2.5l and was unsure of its capability I also will be running 6-8psi to avoid significant engine mods.

I look forward to your progress.

[rowanhol 0]

I'm not 100% sure what the sc14 came on, 2 or 2.5l i think and i think they run 8psi on that engine(i'm about 50% sure of that lol)

what i do know is that they push 1.4L of air per revolution with a max rpm of 10,000..

so bassicly i'm going to have it reach max revs at 6000 engine rpm, my rev limiter is 6300 but i very rarely rev to limiter so should be sweet.so my boost is definately limited due to the small size of the supercharger.But like i say, anymore than that and i'd have to rebuild half the engine.

i got my flatmate to calculate how much psi i would get,and on paper was 6psi and 311hp at the flywheel.. then we estimate a 1.5-2psi drop going through the intercooler and piping.

i'ts going to be alot of trial and error for this build but hopefully be worth it.

there should be an online calculator for working out the psi for your engine, i might ask my flatmate nicely if he can do it for your m50 though.

i'll keep you posted with how the project is going

[Mike 1]

I wouldn't bother with an intercooler, not worth it for the small amount of boost you plan on running. Pressure drop through it will probably negate any gains through the cooler air. Unless you guys have done the calcs and found otherwise?

[topcat 11]

http://not2fast.com/turbo/compression/compression.shtml

most helpfull when dreaming up hp numbers.

the turbo maps are a little out dated but you get the idea of whats going to work.

do your home work to find out your desired ve numbers etc to be 95% most accuarate

biggest Q is 'can my motor handle it'?????

well it still is for me anyway

[topcat 11]

Also, the water to air intercooler i'm selling has less the 1 psi drop.

worth thinking about.

[rowanhol 0]

i was thinking about running without an intercooler but since i'm not retarding the ignition and just using a rrfpr i want the air to be as cool as possible, to be on the safe side rather than performance, may sound like i'm taking a step backwards but don't want my engine detonating..

already ordered an intercooler,550x140x45, should fit behind the bumper super stealth. couldn't really be bothered with the plumbing involved with a water to air intercooler.

now i need to find a 200mm crank pulley 4pk i think,will check when i get home, hmm

Edited July 23, 2007 by yeeeargh

[topcat 11]

i was thinking about running without an intercooler but since i'm not retarding the ignition and just using a rrfpr i want the air to be as cool as possible, to be on the safe side rather than performance, may sound like i'm taking a step backwards but don't want my engine detonating..

already ordered an intercooler,550x140x45, should fit behind the bumper super stealth. couldn't really be bothered with the plumbing involved with a water to air intercooler.

now i need to find a 200mm crank pulley 4pk i think,will check when i get home, hmm

Plumbing??? what plumbing?

cant be easier. mount the 25mm thick radiator infront of the aircon.possibly without removing the fan.you are running a e34?

plant the water/air unit anywhere there is space and buy sum cheap garden hose.and a small pump.

or cut a 3" or so hole though everything and paying large $$ for silican elbos and bends etc.

but each to there own

[rowanhol 0]

well don't really want to have to plumb up the water etc, and fit the extra radiator and get a pump,not my idea of simple, maybe for some it is but for me putting in small front mount seems simple... still going to need a fair few joiners with water to air setup..but yeah def more with a front mount. most water to air setups look like bird sh*t on a balck shoe aswell

[E30-OLLIE 0]

Hey mate, I'm new to bmw's but have been a toyota nut for ages.

Careful with the SC14, from what I know you can't get parts for them anymore.

Was speaking to a Toyspeed member who works for Toyota in Wellington.

He reckons the parts for these are no longer made, ie: seals cannot be bought!

Let me know if you hear anything different as I know a guy who is desparately trying to find some for his SC14

Ollie

[rowanhol 0]

Ok cheers, will be in touch if i wreck it and manage to find parts haha

Edited August 3, 2007 by yeeeargh

[crshbndct 0]

found some nice machined alloy replicas of the plastic bosh compressor bypass valve on ebay, should be exactly what i'm after, stays open under engine vacum and closes as soon as positive pressure is present in the inlet manifold..ace

not 100% sure on what you mean but my setup will run roughly 4-6psi max, estimated with max revs the supercharger can handle. myte be able to leave the supercharger constantly engaged with this bypass valve as it will only close and build boost when you stomp your right foot.basicly freewheeling at idle and cruising.

i just didnt want to use bucket loads of gas when cruising at constant speed on the open road

i am looking for something similiar to this - what size is the valve? i.e. what bore size etc does it have?