AdOz
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| posted on 30/10/14 at 07:41 AM |
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Bmw M42 Supercharged project
I'm currently gathering parts to supercharge an m42 engine for my 76 bmw e10
It was kind of a spur of the moment decision so I'm kinda researching as I go along
I have got an Eaton M62 which still has the merc pipes attached for £150 I also picked up a nissan gtir manifold which I plan to split and build a
second half to suit my port spacing and injectors and engine flange etc.. From what I've been reading 30lb injectors are what people tend to use
on boosted m42s usually from a Volvo so that will be my next thing to source along with a high pressure fuel pump and FPR
My main question at the moment is people who have done supercharged builds with eaton blowers.. What do you do with the bypass system?
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rdodger
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| posted on 30/10/14 at 09:02 AM |
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For a bypass I used one from a MINI when I supercharged (M45) my MX5.
A few things to consider
Where is the throttle body going?
What are you going to do re the clutched pulley?
Belt tension and alignment are key to getting a reliable set up
Have a look on google, MX5Nutz for SC mx5's loads of relevant info there.
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rodgling
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| posted on 30/10/14 at 09:48 AM |
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GKD may be worth a call as they have a super-charged offering for the M42:
http://www.gkdsportscars.com/supercharger-kit.html
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BaileyPerformance
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| posted on 30/10/14 at 09:51 AM |
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We've just mapped a BMW 318 (1900cc) fitted with an M45 supercharger.
Have a look at our facebook page for pictures
www.facebook.com/baileyperformance
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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AdOz
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| posted on 30/10/14 at 03:36 PM |
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Thanks guys
Il check those photos now
I've had a look at the GKD kits before for a but of research obviously that's a smaller charger but the same principle applies.
I planned to incorporate the pipe work that's fitted to it already for the throttle body pretty much straight before the charger with the filter
before that as space is kind of an issue. I haven't got the engine itself yet so il have a lot of measuring up to do for brackets but il more
than likely aim to run a pulley in replacement for the viscous fan straight off the crank and use a later alignment to set it up. I'm aware
tension is a major factor it was something I was still thinking about at this stage
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bi22le
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| posted on 30/10/14 at 06:12 PM |
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Most people would either use the method that comes with the charger or just plum in a recirc valve between the plenum and pre SC. Vacuum comtrolled
from behind the throttle butterfly.
when I finally get to converting mine I will be trying something different. I also have an M62 but will be using it on a 1.6 so it will be too large.
Im going to spin it at the normal speeds to reach 1bar fast but have a waste gate with 1bar spring to regulate the boost.
this means that my boost curve should look like a turbo boost curve without the lag. It also means that I get more torque and avoid the peaky power
curve you get from an SC set up.
we will have to se if it works but I cant see why not.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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AdOz
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| posted on 30/10/14 at 09:15 PM |
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That is a good idea surely the flow rate of the waste gate should be taken into account as if it relives at the boost pressure it will actually open
at boost pressure and relieve the pressure therefore you would loose the boost through it? I'm not sure on the sealing faces in a waste gate
I'd imagine with it being air it would be a soft sealing face? (Metal sealing face would most likely have a leak rate at 0.9 bar under API527 if
they run under relief valve standards which may not apply with it being on a car) I may be overthinking this totally but logically to me you will need
to calculate the relief flow rate of the waste gate against the flow rate of the charger at set rpm to ensure you could hold that constant boost?
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bi22le
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| posted on 30/10/14 at 10:54 PM |
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The flow rate does need to be considered to make sure it does keep up with the CFM. Do remember that it does not need to flow the CFM for the engine.
It is branched off the main boost pipe and just leaks off as required.
The sealing surfaces I think are a seated metal vs metal. They are used to dealing with very hot gas so I doubt there are rubber gaskets hanging
around.
From my understanding the wastegate is better in this situation than a normal dump valve (recirc or BOV) because it CAN hold boost. Remember these are
normally used to control the boost on a turbo exhaust housing so it will hold boost until either it becomes more than a predetermined amount (normally
governed by spring strength) or actuated via a control vacuum.
Look at the tial 70mm ones for an idea of their design \ capability.
By the way, I dont know if this would actually work but I am will to try it on my car when I get around to it.
[Edited on 30/10/14 by bi22le]
[Edited on 30/10/14 by bi22le]
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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AdOz
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| posted on 30/10/14 at 11:13 PM |
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You may be on to something now I think about it I was thinking more in terms of a bov actuated by vacuum as on many turbos it is relieved when the
throttle is released similar to the idea of using the bypass I asked about in this thread I imagine
However there are solenoid actuated valves this may be an option? Especially if there was a way to run it through your management that would be
awesome!
It would allow a lot of torque! Although I'd be looking into a decent intercooler and plenty of airflow to it as they generate a lot of heat
compressing the air and that way would generate even more! Wouldn't want to detonate your motor with crazy hot intake temps!
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bi22le
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| posted on 1/11/14 at 02:22 PM |
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quote:
Originally posted by AdOz
You may be on to something now I think about it I was thinking more in terms of a bov actuated by vacuum as on many turbos it is relieved when the
throttle is released similar to the idea of using the bypass I asked about in this thread I imagine
However there are solenoid actuated valves this may be an option? Especially if there was a way to run it through your management that would be
awesome!
It would allow a lot of torque! Although I'd be looking into a decent intercooler and plenty of airflow to it as they generate a lot of heat
compressing the air and that way would generate even more! Wouldn't want to detonate your motor with crazy hot intake temps!
I am now blurting out of all of clever ideas that have taken an age to consider, design and check but hey ho. Ill let you into another secret.
There was a concern of mine that I would be "wasting" effort in compressing air lots of air, cooling it and then just releasing it with no
gain. This is even more the case when you use an oversized SC spinning at normal rates to create the power \ torque curve I desire. So I came up with
an idea that I was going to incorporate into my design.
If you have a decompression chamber (essentially a large capacity chamber to slow the velocity of intake air) right in front of the SC inlet you can
recirc the "wasted" compressed air into that. The clever part is that the air being "wasted" is now relatively cool and
compressed air. Releasing this into a chamber at atmos pressure will cool its self and the air in the chamber (simple refrigeration physics where
decompressing gas cools). This means that the "wasted" air is infact cooling the slower moving air that is going through decompression
tank on its way to the SC. We all know what that does!
This means that the final engine inlet temp should be cooler than if it just BOV or did not put this "wasted" air to use. Now this does
happen on recirc set ups (depending on set up) but NOT bypass (stock Mini and merc set ups). The difference being with my set up is the amount of
"wasted" air is a lot more and therefore the cooling effect is greater.
Cool or what!?!
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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AdOz
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| posted on 1/11/14 at 09:42 PM |
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Interesting theory you have there I can wait to see it put into practice.
I came across this it would be good to see the car and what was achieved
http://rennlist.com/forums/928-forum/662715-using-a-turbo-wastegate-in-a-supercharger-application.html
You have certainly got me thinking a lot deeper about what I'm doing now seeing if I can create a better system than the ones people are
currently using (which lack of cooling is my main concern atm) and also the bypass
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AdOz
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| posted on 11/11/14 at 10:37 PM |
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Picked my engine up so it's time to get to work!
Photos to follow
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bi22le
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| posted on 11/11/14 at 11:12 PM |
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Are you going to implement any of my ideas?
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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AdOz
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| posted on 12/11/14 at 06:00 PM |
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At the minute I'm just going to be stripping it and figuring out positions and making the manifold
I'm still thinking about that it was a great idea but I dunno whether to take the plunge or not yet! You go first haha
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