VN-VP-VR SC14 How To

[JA2Z]

Hi Lads,

I'm machining a pulley to suit my CRS kit and plumbing 3" s/steel piping to the IC, so my blower ins't on atm.

I had my TB in front of the blower, but when you close the TB all your silicon bends suck in and compress, which means when you press the throttle, the air flow/pressure in the manifold doesn't match the air flow through the TB which makes your mix richen and cause your revs drop for a split second until the silicon bends have popped out and the mix is accurate.

The only fix i can think of is to only use aluminium or s/steel bends and only use silicon joins to join the bends together and give you a bit of vibration protection.

Is there's a better way...?

 

[Bz Kn33z]

Yes there is a better way, a bypass valve, its not as hard for people with a normal crs kit and running low boost, as for people running twice the boost and will suck in more, also having more silicon joins being intercooled. i think something small may work for the time being if not i can go back and have no bypass valve, its just trial and error, i thought i may as well have a play with it and will post pictures and info on it and try new things as i go along but may take awhile from unexpected circumstances.

 

[mookschank]

Might have a spare SC12 ABV kicking around if anyones interested for tinkering with?, will find out this weekend.....Diameter of pipe is 25mm. Bypass activates under manifold vacuum (not sure what figure exactly) and under high boost, i think +10 psi....Here's what they look like....

 

[JA2Z]

Hi Bz Kn33z,

I'm trying to get my head around what you mean. The issue isn't boost pressure in the piping, it's the vacuum.

I can see what you mean by how a bypass valve would take load off the blower when the TB is closed and it has no air to take in, but I don't understand how that will stop the bends from sucking in because the engine will still want it's air.

I'm going to use the original BOV that came with the kit and just plumb the input/output to either side of the blower and use that as a bypass valve. But that won't fix the bend issue because it's not the supercharger that is causing them to compress, it's the vacuum of the TB being closed.

 

[needwork2-4fillhabbit]

Yer thats the problem, A bypass system would somewhat rid that. Although you can just weld in bends or cut up some spare pieces of the piping and put them inside the bends and hose clamp them in to make sure they dont move, i think stig or pub24/7 pointed out earlier that with the tb infront of the blower you cant have more than an inch gap between piping and silicon or it will suck inward.

 

[JA2Z]

"...or cut up some spare pieces of the piping and put them inside the bends and hose clamp them in to make sure they dont move..." - needwork2-4fillhabbit

lol, cool that's exactly what i did. i will have to bite the bullet and spend the money buying the bends then weld 'em together.

 

[Bz Kn33z]

I didnt mean the boost is an issue with the sucktion, but people who have more boost is usually have an intercooler and it will cause more problems in silicon joins sucking in cause there is more, and with higher boost it will be putting more stress on the blower and creating more heat and no dout keeping the blower cooler will prolong the life of it, if a simple bypass valve is fitted it should make it a more efficient setup.

 

[JA2Z]

... make sure foamy knows the tune is a tb moved tune to...

I checked with Foamy, No difference in the tune wether the TB is before or after the blower.

Bz_Kn33z, yeah i do have an IC, hence my question to wether there is any alternative to using metal bends to stop the silicon bends compressing. It's ok, i'll suss it out, for now i've put my TB back onto the manifold, so i've plumbed an Atmosphere Blow off valve instead of a bypass valve.

 

[Bz Kn33z]

Sure you can use metal bends, stuff them in the pipe, or are you saying have no silicon bends and just welding all the bends?, if so how will you get it off when you get done for the blower being on lol.

 

[JA2Z]

Yeah, either/or. If I use solid bends I'll join the pipes on the straight sections with the pipes butted together. You also have to remember that your engine moves quite a bit under normal operation, so you have to have a couple of flexible bends or straight joins somewhere to absorb the movement.