I have a stock l98 and a paxton charger and am going to run about 6 psi and maybe get a pulley for 9psi. What kind of pressure relief system do you guys recomend? I have heard blow off valves, bypass valves, and surge valves. Which one is the best for me? I just want to protect the charger.



BTW I know this should go in the parts wanted section but ill throw it in anyways. Anyone have an oil cooler for an sn93 blower?


Thanks

 

If you are useing an automatic tranny . I don't think you need a Wastegate.

 

its always a good idea to give the boost somewhere to go when the TB closes...blow offs work nicely...

 

why not?

 

UMMMMM???? If he is running a Supercharger >>>ANY SUPERCHARGER>>He does not need a wastegate...LOL


Wastegate is used on a turbocharger to LIMIT the amount of exhaust going to the turbo and thus limiting the amount of boost created...

A BLOW OFF VALVE goes on the dicharge tubing of a SC or turbo charger and is connected to a vacuum source... When you quickly let off the throttle and ecess pressure builds due to the throttle blades closing this imbalance opens the valve and vents the air to the outside instead of putting excess pressure on the impeller..

Wastegate and BOV are 2 different items.. For instance my car uses BOTH.. For 2 completely different reasons.

a BOV is NEVER a bad idea.. I have an Automatic..I used a small vortech/greddy unit with my vortech...I now use a TIAL with my turbo setup.. For 9PSI the small greddy/vortech unit would be fine..

 

To add to Kenwood's excellent comment, a surge valve is used only with a supercharger. When in vacuum, it allows excess air that the supercharger produces that the engine does not need to vent, either back to the supercharger inlet or to atmosphere. Under boost, this valve closes, allowing all the pressurized air the supercharger can make to fill the intake tract.

 

LOL I need to read better.. I did not even see the surge valve comment.. Good catch willie..

 

Opps I forgot it said SUPERCHARGERS and BLOWOFF valves

I keep thinking about turbos lately

 

Also called a compressor bypass valve (CBV) on turbo setups. Always vents to the intake tract. That is what you see on the production vehicles. Vaccuum opens the valve to bypass. Overboost will force it open overriding the spring force.

Have you been able to start the turbo install yet?

 

Easy to do...Ive not thought much about a SC since I got rid of mine 2 years ago...

 

i was thinking he was meaning turbos that were auto trannys didnt need wastegates... its cleared up now anyways+

 

Nah , car is in storage here. I still am researchnig the 749 swap and tracknig down a fuel setup I wanna run too . For starters I am just gonna run 6 psi ( I got the wrong pistons in it for boost 9.7:1 CR ) . Might be able to afford it in the spring ...not too sure yet.

 

I did a search and came up with this thread and some good informative posts. On my setup, I don't have a blowoff valve hooked up right now. My new setup is running okay, but my buddy keeps telling me that I need a Bypass or surge valve, not a blow off valve. He says that it won't run so rich at idle if i get one, because the car won't think there is so much air coming in as it does now. He said that it will also help idle, since i won't be "cramming" so much air into my IAC. He says that if i hook a bypass up, I will have to reset the idle and TPS, and then maybe have to drill holes in the throttle blade to let some air in, so the IAC won't be maxed open (like he thinks it is now) and so that I don't have to have the throttle blades so far open, which is also causing my idle problems. It really doesn't run too bad now, but the idle is a tad low and I can't get it higher no matter whaat I adjust. It really needs to go up about 1 or 2 hundered rppms, cause when it's in gear, it's a little to low. I did make up a temporary bypass that vented directly from the discharge to the intake duct, and it started surging a lot. He said that even though it was surging worse now, once I had the proper chip burnt and drilled holes in the TB blades and install the surge valve it would improve. He thinks that The IAC is getting too much air and is fighting the other sensors and whatnot. He thinks I need to leak some air into the TB, UNMETERED...Also (FYI) the motor seems to like more than 16 degree base timing,...but it is a big cam. My total advance seems to be a little high at about 36 degrees. I will correct that with the chip. Anyway, will what he is saying help get my idle a touch higher, less rich and better even though when i rigged up a bypass it seemed to surge? Also, I think my BOV bung is about 1 1/2", and I would like to get a surge valve to fit that existing hole. Can you recommend a good one that will fit. I just want to recirculate some of the pressure from the discharge tube back into the intake after the MAF sensor. BTW, I also vented the discharge directly to the atmosphere with no restrcition and it seemed to sound very "cammy". I think maybe it was rich? i don't know, but it sounded real good and it didn't surge when i vented directly to atmosphere at idle. weird. only surges when i re-circ the air./ Thanks oh yeah, he also said that it should increase my drivability around town/