How much psi will a stock wastegate let through?

[vrooom]

ok just to be sure since i'm a "newbie" if i have a upgraded turbo (18g) and my wastegate is stock with no boost controller the stock wastegate will only let out about 7psi only righhhtttt? sorry for the noob question just wanted to make sure my answer is the same as the people on here. Thanks! and yes i have fmic and 3" catback exhaust and stage 3 clutch and a tial bov. The only thing i dont have is a ecu it is a stock tune and no injectors or a boost control


Thanks once again your opinions will help in any way and if someone posted the same question i'm sorry but i didnt see any one post anything (I actually searched)

 

['97 Cayenne]

the upgraded turbo's wastegate will open at its given psi rate, which you need to find out what that rate is. As i'm not familiar with the 18G

 

[vrooom]

Ok i was just making sure because the guy i bought the car from was stating that the car has a stock wastegate and that it will only let out the stock boost to the car and not run higher than 7-10psi but obviously thats not the case?

 

[XiKeiyaZI]

Wastegate actuating pressure is determined by the wastegate and nothing else. You can manipulate this using a manual boost controller but, this is only added for clarification purposes.

Now, you are aware that stock boost pressure on an 18g is much different than stock pressure on a stock turbo, correct? The question is ; why are you upgrading your turbo with no fuel compensation, no way to adjust it, and no way to monitor it?

You need to update your mods list in your profile for better help, also.

 

[QuikinCO]

hook your wastegate to an air compressor and measure the spring yourself, its very easy to do then you will know for sure what the spring pressure is

 

[vrooom]

As I stated earlier I purchased the car as is the car was half way moded because the person that was getting the work done got into a bind and could not afford to finish the car as to the engine and tranny was out of the car being worked on but again he couldnt afford the car so they put everything back in and sold it for 3000 they way i stated earlier with a fmic 18g turbo 3" cat back exhaust system all the way back and a stage 3 clutch. I think i'm just going to slap on a manual or electric boost controller and run it at stock boost until i get injectors and a tune makes no sense to me either why he did it half way seems like people these days rather ruin a car than actually take the time and money to invest into rare living legend!

oh and a tial bov sorry

 

[5taR]

You need all your fuel upgrades. That 18g is going to feel slower than a stock 14b.

 

[vrooom]

Yeah i mean the only thing i'm worried about is going high into the rpms and blowing a gasket or a head.

So if i get injectors how big will i have to go i think i'll put injectors and a boost gauge on and save a little bit then get a eprom ecu and get it tuned last after all the add ons

 

[XiKeiyaZI]

You don't need a manual boost controller to run stock levels. You only need to run a boost source to the wastegate nipple. A manual boost controller can only raise boost, not lower it. Run a line from somewhere in your charge system to the wastegate nipple and be done. It's going to feel laggy, but you're not going to blow up anything like that. You may break up a little under boost, but it's doubtful. This is, of course, assuming that the boost is no higher than 12psi on that wastegate. You need to measure this first.

As for injectors, for an 18g you should be fine with 750's, 850's if you want to play it safe. Now, before you up the size of your injectors you'll need a way to compensate for them so you need to pick up a tuning solution FIRST and make your adjustments upon installation. Not months down the road. Also, get your basic gauges and monitoring suites taken care of asap. You need to be able to monitor boost, AFRs, and temperatures as well as oil pressure. So go pick up a decent boost gauge, a good Wideband, and get it put together correctly.

 

[vrooom]

until then looks like i'm staying out of boost

so is it recommended to use this car as a daily driver? I think i can stay out of boost until i get the AFRS, Injectors, Boost Controller, and ECU Tune. But i think i'm gonna play it safe and not drive it until i get those things done

 

[laserspeeddemon]

You can get into boost just fine. I believe the stock pressure on the 14b/16g/18g is around 8 psi. The 18g will flow more than a 14b so that should compensate a tiny bit for the lack of psi (though probably not much).

If you rasied the boost levels anywhere more than 13psi you should start to consider altering your fuel control.