Talk to me about Turbo Blow Off Valve

it should be a pressure relief valve, so when he takes his foot off the gas the Car wont over boost and kill the engine. since he already has a trubo/turbos. it should be a matter of switching out the old ones for the new ones. Its going to be really loud when hes done. Ie a cop magnet.

 

The way I understand it, each turbo should have a wastegate that limits its full boost pressure (which I believe is 14psi on the Stealth). If there is a single blow-off valve operating in the range of 10-25psi, it would have to be mounted on the intake manifold (is there enough clearance under the hood?). The only time this blow-off valve would be operating would be if it were releasing boost pressure from the manifold, which would basically be .....just about never, and only if the car was being WHIPPED. And what is the point? To make noise???? Do the car and the lad a favor - have him spend the money on some nice tires, or some gas, or insurance. This thing is a waste.

 

Bill

Do Not Pass Go. Do not collect $200.

Go directly to:

http://www.3si.org/forum/

Almost as big as Fchat, but focused specifically on the Stealth/3000GT.

All Stealth/3000GT knowlege will be revealed.

 

That's not how they work. When you close the throttles, you send a whopper of a pressure wave back toward the turbo. With the blowoff valve, that doesn't happen, as the turbo continues to spin and "blows off" pressure, because the vacuum in the intake opens the blowoff valves. The advantage is that you have less lag because the impeller continues to spin (for example, between gears while shifting while the throttle is closed VERY briefly) and you are easier on your turbos.

 

right, and make sure you vent un-metered air or it'll screw up the AFR. blow off the pressure before the air mass sensor, or you'll have to re-route it back into the manifold i.e. bypass.

i just bought one for the mondial SC project. it's a HKS sequincial valve. 9second racing had the best price, from shopping around.

 

They sound cool as hell too

I love the flat 4 WRXs with blow off. Sounds evil.

 

They claim for a faster throttle response as well, but I didn't notice a change on our car. I mainly bought it as a turbo saver, keeping the rush of air from abruptly forcing the turbo to spin the opposite direction. Tell him to look into going for a single turbo mod.....Are the Turbos on the car sequential or non-sequential?

 

I used to have a vid of a Quail Counding BOV(actually billet made) on a 1st gen TT Rx-7(13b-rew motor).
But, here are some others, lol....
http://youtube.com/watch?v=h5mrQmQ_W8E
http://youtube.com/watch?v=lZG0RS3mVBc
http://youtube.com/watch?v=Erjhkv9AzKY&mode=related&search=

 

Install is a snap with the TurboXS H-3000gt...

about $40

http://www.turboxs.com/shop_prod.php?what_category=5

Craig

 

I have a 97 Supra twin turbo. I left the factory blow off valve in since it recirculates. I have a blitz venting one on the other side of the intercooler. Some guys take out the factory one and have an external bov. At idle, if they hit the gas, the car almost die since there is not air. That is why I left my stock one in. No idle problems

 

The 3000GT/Stealth has a MAS at the filter before the turbos. Using this blow off valve will cause a rich condition every time he lets off of the throttle because air that had been accounted for by the MAS will no longer be in the system. Some of these cars do not have much of a response to this, others run terribly, there really isn't any way to predict this. My advice would be for him to pull the recirculating hose off of his stock blow off valve (aka compressor by-pass valve) and plug the end of the hose that leads back to the intake. This will do the same thing that the RFL would do. Take it out around the block and see how bad it runs.

Honestly though, I would highly recommend against the RFL. Its loud, obnoxious, does not sound good, and you are making the car run worse. There are plenty of other things to spend money on that will actually improve the car. If he gets an open air filter intake kit, you will be able to hear the stock blow off valve, even though it is recirculated.

There is a stock blow off valve and it is located at the Y-Pipe. The compressor outlet pipes from both turbos run up and join on the left side of the intake manifold into a Y-Pipe, which then feeds into the intake manifold. Therefore, one blow off valve, not two. Tell your nephew to spend his time reading long before he starts throwing parts at it. There is so much knowledge out there about these cars, most of the owners work on them themselves. My best friend is very big into the Stealths (I'm obviously on the DSM side of the equation) and he's put a Stealth through the quarter at 12 flat on the stock turbos (which look like they belong on a weedeater). He didn't do it by wasting money on flashy blow off valves or colored hose, he did it by carefully selecting parts after a lot of research and spending a lot of time fine tuning everything. He's since rebuilt the entire engine with larger turbos and then got rid of it. He's just now sold his second stealth and I don't know what is coming next. Your nephew should get into the community early on and he will save himself from committing expensive mistakes.

 

this is good help right here, learn from others and save yourself the time and money. i've pioneered many a project, that in the end helped alot of others save money and time. which is the point of many of us getting together to help each other.

 

FYI, there are dual vent BOVs that recirculate the intake charge at lower boost levels, while venting to atmosphere at higher boost levels. This eliminates any driveability issues that occur due to MAFs not seeing the required airflow. They're generally quieter under normal use, but can be as loud as some of the other vent-to-atmosphere BOVs at higher boost levels.

 

I had one on my modded WRX, and ran into problems with it leaking....just to think about, there might be better BOVs out there. take a look at HKS SSQV--its a piston valve and incapable of leaking. If you need help finding one, send me a PM.