Supercharging an N/A

[nathanH]

Dont all laugh at once.

Would this type of system work, its just a simple drawing i put together to simplify my idea, I am looking into supercharging and have read alot of stuff and other poeples projects on other forums and found this to be the most efficent setup. The engine i have in mind is an F7P running a low boost 7psi max Eaton M45, Im not thinking about mounting just yet but the theory behind doing this. There are so many little problems i have come accross hense the post as i thought my ideas could be expanded upon and/or discussed. Things that I can see being a major issue is management and the need for a stand alone and a map sensor that can read positive pressure. Agian this is just an idea so no typical CS bullshit like buy a faster car, as i already have one.

I cant see this type of system causing to much of a problem, maybe lower the compression but i dont see the need with under 7psi. also hense no need for an IC. correct me if im wrong tho.

btw im shite at explaining things so bear with me.

The way i see it is, on idle, there is vacume behind the throttle, vacume opens the SC bypass valve. on full throttle pressure is allowed to build in the inlet thus closing the bypass valve and allowing the SC to create full boost pressure, upon lift off/gear change the throttle is closed and vacume is created and the bypass opens to recuirculate the boost not to damage the charger. On normal revs the bypass stayes open as there is insuffiencet pressure to close the bypass thus inproving efficency.

nathan

 

[Craig]

hasnt someone supercharged there 172 on here. i am sure i seen it the other day

 

[stan*]

Why the need for a bypass valve?

At idle speed, there wont be enough pressure to cause any sort of damage..esp if its geared to peak at 7psi.

It would need a 2 bar MAP sensor, and the ecu adjusted so it could read above atmospheric pressure, then calbirated to suit.

Cr could stay std, and some form of charge cooling would be beneficial.

 

[nathanH]

I have seen people using a bypass valve to aid fuel effiencey and also to release pressure at high rpms.

what sort of Psi would cause damage, the way is see it is prevention is better than cure, Charge cooler would be benificial i suppose. can the standard Ecu be recalibrated to read positive pressure? hense the stand alone jobbie. am i correct that BBPT sell a 2bar map sensor?

can you suggest any other setup?

nathan

 

[BenR]

eatons hate back pressure, you'll need the bypass to relieve the pressure between charger and TB on overrun.

But why that way, why not the normal way of charger post TB?....you'll still need a bypass though between upstream and downstream of the charger.

 

[nathanH]

how would the bypass be opened/closed? as there will always be pressure after the charger. there will be no place to take a vacume to control the BPV on overrun.

you mean like this? would that work tho?

 

[BenR]

That is the way its always done.

There is no boost after the charger if there is no air entering it, just vacuum.

Your just allowing the engine vacuum to bypass the charger to avoid damage.

Vacuum line should be post charger aswell as at low throttle angles you will still have negative pressure and the engine will want to pull off infront of the charger without any additional boost, for cruising etc.

 

[nathanH]

oh i get it. so i would need a vacume pipe before and after the charger that feed the BPV? what about management what do you suggest?

 

[BenR]

no, just after.

There are tons of different ECU's to choose from.

What sort of budget?

 

[nathanH]

something that would do the job im asking? not looking to spend thousands, say £400 plus mapping

 

[BenR]

Drop me a PM, i've got a mate that will be able to sort you out no problems.

 

[GordonD]

Your just allowing the engine vacuum to bypass the charger to avoid damage.

Eh?

If the throttle's closed the supercharger would have vacuum on both sides of it whether you had a bypass or not.

 

[BenR]

consider the vacuum sources, if they are equal, and if the charger will like it.

 

[GordonD]

consider the vacuum sources, if they are equal, and if the charger will like it.

This is getting too Eastern mystical for me.

I think I'll stick to engineering ...

like how and where you fit an Eaton M45 in the engine bay of a Clio.

 

[BenR]

If you stick to engineering then you'll see the sense in why ever OEM and aftermarket manufacturer of positive displacement chargers use BPV's. Its not too hard to understand engine vacuum demand is different than the pure gearing supply of the charger, whether the throttle is open or not.

And to fit in a clio bay you have 2 options. Remote mount with a twin bearing supported drive shaft, or remove inlet manifold and fabricate a small 3"runner with plenum for the charger to bolt directly to.