S/C boost regulation?

[CT9A]

How would you regulate boost with a Vortech style supercharger? My boss is seeing some unwanted boost spikes as he drives his car into lower altitudes and wants to keep boost from exceeding 9 psi.

[Nightfall]

I thought that superchargers were regulated by the size of the pully

[CT9A]

They are, but at lower altitudes I think they build more boost.

[Nightfall]

Right. He's forcing in 9psi above the atmospheric pressure at sea level vs. 6000+ ft.

I have no clue.

[kingbobdole]

pull the brake booster line off :P

[Skaterkid]

Put a bigger pulley on it or get a pop off valve.

[CT9A]

Would you be able to use a BOV with a 9# spring as a pop off valve or would this create too much of a leak?

I read that the HKS Racing By-Pass valve can do this, but i wanted to check first.

[ComputerJLT]

you could use some sort of bypass valve but thats not effecient.

Ditch the supercharger and go turbo or run a bigger pulley (less rpm at the supercharger hence less boost)

[CT9A]

This is on a SRT-10 Viper. I know he wants to go twin in the future, but for now, he's worried at warping the cylinder walls (claims that happens at 9 psi for those motors). So he just wants to be able to regulate the boost when he's at lower altitude without sacrificing performance at higher altitude.

[boostedEG]

his best bet is changing the pulley. i know for eaton style super chargers they make an adapter that allows quick changes (like 30 minutes) if he frequently goes from one altutude to another. i would think they would make those for vortec style S/C's aswell.

i have heard of using a wastegate on the boost pipe also, but the reason they typically dont recomend this is because you are then spinning the charger faster then needed, putting more wear on it, but in his case with him going back and fourth between altitudes it might work good.

[i drive crap]

If he doesn't already have an underdrive pulley set, the bigger crank pulley might be enough to yank some boost out of the system...??? or a bigger S/C pulley, or come back to colorado!

[Brian]

probably going to have to change the pulley plain and simple.

[ComputerJLT]

This is on a SRT-10 Viper. I know he wants to go twin in the future, but for now, he's worried at warping the cylinder walls (claims that happens at 9 psi for those motors). So he just wants to be able to regulate the boost when he's at lower altitude without sacrificing performance at higher altitude.


what? Your friend needs to look around some more. I've seen stock block vipers make 1000+ HP w/ internals. 9psi on that stupid-charger won't break anything :p

/edit: or it may because superchargers have awful abdiatic effeciency and if its non-intercooled you'll detonate hardcore; but it will break pistons/bearings/pit cylinder heads before it does anything to the block

[Brian]

It depends on tuning, fuel system, etc. Iwould run a smaller pulley and avoid the problem. Especially on a car that expensive. It isn't worth taking the chance. I know some guys were able to regulate boost on roots blowers by using a computer and adjusting the actuator on the bypass valve, but that was a purpose built system. I don't know if there is anything remotely like that for a setup like he has.

[ComputerJLT]

It depends on tuning, fuel system, etc. Iwould run a smaller pulley and avoid the problem. Especially on a car that expensive. It isn't worth taking the chance. I know some guys were able to regulate boost on roots blowers by using a computer and adjusting the actuator on the bypass valve, but that was a purpose built system. I don't know if there is anything remotely like that for a setup like he has.


Supercharger suck; end of story. tell the guy to throw a smaller pulley on there until he can get a turbo

If you can't tell i hate superchargers

[Brian]

Superchargers are not that bad. They give great low end power and can make TONS of power on larger engines. I would probably never run one again on a small displacement 4 cylinder engine, but they are great on a larger V8. I would rather have a turbo in most cases, but there is nothing wrong with a supercharger. I'll probably supercharge my vette simply because it's easier to install and maintain.

[CT9A]

what? Your friend needs to look around some more. I've seen stock block vipers make 1000+ HP w/ internals. 9psi on that stupid-charger won't break anything :p

/edit: or it may because superchargers have awful abdiatic effeciency and if its non-intercooled you'll detonate hardcore; but it will break pistons/bearings/pit cylinder heads before it does anything to the block

He's getting close to the 1000 mark. Last time he laid down ~880hp @ 8psi. Since then he's installed a meth kit and is supposed to be getting re-tuned sometime soon.

According to him (I have never really paid attention to what Vipers can/can't do) the SRT-10 starts to warp cylinders at 9.5psi and up. I did start thinking that maybe he meant the heads lifting from the block deck (something he said made me think that, can't remember what it was though).

Oh yeah, it isn't intercooled.

[stu]

Isn't it a larger pulley to decrease boost?

[ComputerJLT]

Isn't it a larger pulley to decrease boost?

yes; larger pulley = less belt speed = less compressor speed = less pressure

[Brian]

yes

[-=[Juztin]=-]

I've heard of a couple Z guys running a wastegate w/ elec boost controller to control the boost of their Vortec setups.

A thread I could search up regarding this: http://www.my350z.com/forum/showthread.php?t=188792&highlight=vortech+wastegate

Another that has a guy who did it posting towards the end of the thread, he even posted pics of his setup. Might be something to consider however odd it sounds. http://www.my350z.com/forum/showthread.php?t=170943

But I like this solution overall for controlling boost...I have one....its called belt slip...from 6000rpm to red line...lol

[CT9A]

Thanks Juztin. I'll pass those on to him.