Budget NA6 supercharge build

[wade]

How much adjustment do you have in your tensioner ..??

The length will probably also be dependent on the size of the bracket that bolts the supercharger to the head :-S

[speed]

Thanks heaps for the pic. Will try and get one and give it a go

This pic is a 1325 with the tensioner backed off.



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[Paulus]

Thanks Speed, I suppose that it could be the SNC issue, but I don't think so, tensioner spins freely

It seems to happen when I lift off the accelerator after load, could it be the little black pressure release valve?

It almost feels like the boost is still trying to spin the supercharger and the engine rpm is slowing, causing the belt to slip, but I though the release valve would prevent this

Suppose I'll just live with it, another noise to the orchestra of noises now emerging from under the bonnet :-D

Belt too loose. Belt needs to be tighter than you can ever imagine possible. Sounds like a guitar's 'b' string when you pluck it. get out your tuning forks!

However, the reason it is doing that when closing TB is because there's boost still in your intake when the TB is closed. I ended up getting a BOV, but still had a super tight belt. A sure sign of belt slip is lots of rubber dust collecting.

Never run anything less than a racing belt if you're 4 rib. gates v belts seem to be the best

[Paulus]

Thanks heaps for the pic. Will try and get one and give it a go

This pic is a 1325 with the tensioner backed off.



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I think you can squeeze that on. Don't forget that belts slacken over time. slip the belt off the pulley to the left and you'll get a bit more room.

Just make sure you don't foul on your PAS (although you don't have one?)

Make of belt?

[speed]

Thanks heaps for the pic. Will try and get one and give it a go

This pic is a 1325 with the tensioner backed off.



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I think you can squeeze that on. Don't forget that belts slacken over time. slip the belt off the pulley to the left and you'll get a bit more room.

Just make sure you don't foul on your PAS (although you don't have one?)

Make of belt?

Thanks Paul.
I did get it on but thought still one or two sizes too small.

Was a Bosch belt from Bursons.

Didn't think I needed a BOV with a twin TB setup. Is this wrong?

What is the function of the valve thing that the vacuum line connects too?

I seriously don't want to run a BOV but if I did it would have to vent back into the air intake for NSW engineering reasons.


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[Paulus]

Thanks Paul.
I did get it on but thought still one or two sizes too small.

Was a Bosch belt from Bursons.

Didn't think I needed a BOV with a twin TB setup. Is this wrong?

What is the function of the valve thing that the vacuum line connects too?

I seriously don't want to run a BOV but if I did it would have to vent back into the air intake for NSW engineering reasons.


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Did I throw in a BOV? I found that I did infact need one, to reduce belt wear and the chirp when changing gears.

The bypass valve is to bypass the charger when off throttle. Vacuum and triggers it to bypass. It doesn't do anything for the pressure already in the intercooler piping. You get a surge heading back to the blower causing it to either stall or increase the load on the belt (increasing belt wear).

I hate the BOV sound, very bogan. you may be able to tweak the setup to avoid needing one. see how you go. for my new setup i plumbed a recirc back in as you say - it wasn't too bad, just more parts to source

I can only recommend micro v-belts. I had to source the size i needed from the UK - depressing. from memory 4pk1230

[Paulus]

Just to add.. belt slip is a real plague for 4 rib setups. Check your datalogs to ensure you're maintaining high boost as the revs climb. The mini SC (MP45) should be capable of 10.5PSI on the 1.6 intake restriction.

Belt slip is difficult to diagnose, on a dyno you can see it pretty clearly, especially on gear change. You'd be shocked at how tight you have to run your belts.

[wade]

Great info Paulus, thanks

Looks like I'll be cranking that belt tighter then ;-)

[speed]

Wade, in a way you are testing all this stuff before me, so I'm interested to know how you get on.

Just to keep you in the loop, Paul is the forum member I bought my SC kit from.



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[speed]

Thanks Paul.
I did get it on but thought still one or two sizes too small.

Was a Bosch belt from Bursons.

Didn't think I needed a BOV with a twin TB setup. Is this wrong?

What is the function of the valve thing that the vacuum line connects too?

I seriously don't want to run a BOV but if I did it would have to vent back into the air intake for NSW engineering reasons.


Sent from my iPhone using Tapatalk

Did I throw in a BOV? I found that I did infact need one, to reduce belt wear and the chirp when changing gears.

The bypass valve is to bypass the charger when off throttle. Vacuum and triggers it to bypass. It doesn't do anything for the pressure already in the intercooler piping. You get a surge heading back to the blower causing it to either stall or increase the load on the belt (increasing belt wear).

Yes, an anodised red Atmo BOV.

Will have to speak to my engineer again and see what he will accept.

Ah, so that's what the bypass valve is all about. Makes perfect sense now!!!






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[speed]

Thanks Paul.
I did get it on but thought still one or two sizes too small.

Was a Bosch belt from Bursons.

Didn't think I needed a BOV with a twin TB setup. Is this wrong?

What is the function of the valve thing that the vacuum line connects too?

I seriously don't want to run a BOV but if I did it would have to vent back into the air intake for NSW engineering reasons.


Sent from my iPhone using Tapatalk

the pressure already in the intercooler piping. You get a surge heading back to the blower causing it to either stall or increase the load on the belt (increasing belt wear).

So a SC suffers blow back like a turbo and attempts to spin the SC backwards?
And that's what Wade is experiencing with his new sound.

I understand that such blowback can occur on non BOV turbo cars but the rolling mass of the SC rotors would be far heavier than 2 turbo wheels on a shaft.

Is this simply a case of 10psi is 10 psi and it has to go somewhere?


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[Paulus]

So a SC suffers blow back like a turbo and attempts to spin the SC backwards?
And that's what Wade is experiencing with his new sound.

I understand that such blowback can occur on non BOV turbo cars but the rolling mass of the SC rotors would be far heavier than 2 turbo wheels on a shaft.

Is this simply a case of 10psi is 10 psi and it has to go somewhere?


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Yes, they do suffer from stalling.. but noticeably with small reduction pulleys and high rpm/load. Stock pulley's dont suffer this problem.. a bit like having a bigger flywheel to reduce idle droop. More mass inertia etc.

From all the belt sounds i've gotten to know, the sound i heard on wade's car sounded like belt too loose or misaligned. Didn't sound like high rpm gearchange stalling .

For your build- try with no BOV and decide if you need one btw- i think i've got a 11% reduction pulley if you ever want it

[speed]

Thanks for the explanation Paul - most appreciated.

I thought that I had asked you if you had another pulley. Will send you a pm or email when I can. You may already know what going to ask. Thanks again.



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[wade]

I want the original pulley.....do you know where you can get them from?

[Paulus]

http://www.kavsmotorsport.com/

assuming you've also got a MP45? Speed- sorry I only recently found the pulley along with other trinkets hidden in the boot of the car