How much should I port out the stock S4 Wastegate? I want only around 8-11 PSI, and when I want to upgrade my injectors, what size should I use, and how much boost can the stock 2mm seals take safely?

 

get a quality aftermarket boost gauge and monitor your boost levels... the more right foot you apply, the more boost you will get. Keep it under 8 psi and you should be good to go. It's a quick fix, but it's better than popping an engine. : ) What you need is a bigger wastegate, which you're going to have problems doing that with the stock turbo... or if you don't want to do that... fit a more restrictive exhaust setup.

Josh

 

You beat me to it. The cheapest way is to stay out of boost.

 

Port The ******* Wastegate Already!!!!!

 

beleive me, do something about it. i just blew my **** this week. had a 3"downpipe, dual 2.5" exhaust no cats, r-tek 1.5, and an intake. i would peg my stock boost gauge. then one night i did a 3rd gear pull and my engine blew. is there any reason that my mods would raise boost that much? but yeah port the fucen wastegate already

 

a) your wastegate wasn't functioning properly b) your very large exhaust is helping cause your wastegate to not open. My car does this with a 3" downpipe and full 3" exhaust. Also have a 3" turbo inlet duct that doesn't help matters. Who knows where my boost gauge would stop if I just let it go in 3rd gear... don't plan to find out.

Josh

 

get a boost gauge, people need to know what they are boosting at so stop trusting the POS stock boost gauge on modded cars, i can't seem to say this enough...

 

ok thanks for all the imput guys, looks like im porting the wastegate,

ok, why on earth would i ask a question like this if i didnt understand the problem im faced with, if i needed the problem and reasons behing it explained to me then i wouldnt be asking about how to fix it coz i wouldnt know running this high boost would cause damage and just be boosting around ***** nilly untill my eng went pop.

aye,

come on guys, i explained i was a tin bum and didnt want to spend lots of $$$$ and was after a cheap solution.

by the way thanks for the heads up on the boost controller thing, damn glad i didnt waste any $$$ buying a controller, maybe after i port the waste gate

heh heh, and yea i learnt quite quickly to keep my fat foot out of it

thanks heaps for the advice

 

The correct answer is neither of these. If the wastegate wasn't working propely the boost would be higher in the lower gears, and big exhaust don't affect the wastegate's operation at all. The stock wastegate is too small, simple as that.

Did you miss the bit where he told us exactly how much boost (in psi) he was running? Sounds like a proper boost gauge to me.

 

please explain this for me guys a lil bit....oh i have fcd already.....and what if i streetport my motor

 

shove a bunch of socks in the end of your exhaust, and fill your air box with silicone sealer VIOLA! you'll be lucky to get anything out fo that setup and now your exhaust will sound UBER DOPE, rofl sorry, im bored

 

ok... my question was never answered..... can someone tell me how much to port out the wastegate? also if there is anyother changes I would need to make? I have a defi boost guage, my car is setup to handle 11lbs, but it'll hit that by 3K giving only 1/4 throttle, it's killin gas mileage. if someone would be so kind to answer my simple question, instead of always posting " Just Port the wastegate" and explain to me how, and how much and , I might would be getting somewhere, and I would most apprechiate it.

 

Port your wastegate to 35mm if at all possible... You shouldn't be hitting 11psi by 3k on 1/4 throttle... That's a direct result of your wastegate being too small... The wastegate is designed to limit the boost, bleeding off anything over the preset amount, but when the engine's flow capabilities are increased, there isn't enough pressure to open the wastegate, thus causing it not to open as soon... That's why you're getting shitty gas mileage, and could prove detrimental to your engine's life expectancy...

 

Nope, that's wrong. The wastegate is opened by manifold pressure, so it opens at the same time no matter what mods you have. The difference is when you increase exhaust flow too much the stock wastegate is not big enough to bypass enough exhaust gas to prevent the turbo from continuing to speed up.

 

i asked this question a while ago, but got no answers, can u fit 1 of those pressure releaf valves found on alot of old turbo engine. what happens is wen maifold pressure overcomes the spring presure it alows the valve to open and wen it drops it closes, thus mantaining a constant boost level

 

You want something like a boost regulator? I guess it's possible, just need to find one or modify one to open at a lower pressure. For the time being, have you ported the wastegate?

 

Not recommended as a constant way to regulate boost.
What this does is allow the turbo to overspin, and the turbo will quickly kill itself.
As an emergency device, sure, it's fine.
But don't use it to regulate boost ALL THE TIME.


-Ted

 

ok, so I port it to 35mm, umm how many thousands is that above factory? also is there anyother changes I need to perform after porting the wastegate? right now my TPS is skrewed up, so it's always runnin full rich, I'm fixing that this weekend, but should I wait till I get my wastegate ported?

 

well, i didnt get to it in time and as said
on a stary night my we turbo running a helft 14lbs shat it self real good. warped the centre shaft in it, bent most of the inlet impellor fins over, smashd up the exhaust propeller (major chippage) and broke the brass(bronze) bearing thing in the middle into 3 peices,

It was glowing like the sun and it lit up my eng bay but DAMMMMMMMMMM my car was hauling ****, my mate whos a V8 bogan who was with me has now been converted and is selling his V8 to by a rotor. lots of fun but a bloody great pain in the ***

 

when i ported mine i just used a die grinder and left it a lil bit under the size of the flapper on it and that seemed to work fine for me