Alright, I ported my wastegate. (Aaroncake's site was very informational btw.) Anyway, he says to port it close to 40mm. I ported mine to about 25.3mm. I was just wondering if that would be enough if I am running; 720cc's all around (RTek v1.8), streetport, and a Racing Beat REV TII exhaust...? or should I port it bigger?

 

it makes sense to me to port all the way to 40mm, dont want to have to do it twice.

 

Yeah, dont bother bro.. Do 40 or more.. mine was ported to as big as the stock flapper would go and it would creep in every gear! I then ported it just a bit bigger than 40 and its good. I've got a 2.5 inch Downpipe, 680 secondaries, 3 inch piping after the DP and a race port... go big or go home

 

Alright, thanks for the advice... but 40mm seems massive. I keep looking at 40mm on my caliper and it just seems like a lot.

 

Bigger is better! You can always raise the boost if you do get it to big but, it's good to have the option.

 

i still don't see the need for a massive wastegate port, it just causes issues with the flapper.

porting as large at the stock flapper can allow for(when done right) will keep the boost around 10PSI or less, it mainly depends on your mods and porting, the stock fuel system with a FCD will be able to handle 10PSI and below. sure bigger is better but most people don't have tig welders and a spare larger flapper arm to do the job right.

 

i have huge issues with boost creep. running 80mm from turbo back exhaust and full tubular exhaust manifold. i was thinking of porting huge but do you think i need it karack? sorry for the threadjack

 

personally i don't but there are others who say you have to eliminate all creep whatsoever, even though most do not ever run stock boost levels anyways..

i have ported within the limitations of the stock flapper on numerous cars and the only one that hit anything over 10PSI was on one that i streetported and it hit 12PSI(all had 3" exhausts, TID, CAI, etc).

most people wind up pushing 8-12PSI anyways so that is within range of the modified wastegate, saves the cost of a boost controller unless you really need more boost, 12PSI is about as high as a stock turbo should ever see anyways.

 

cool thanks. i want to stay stock boost numbers since im running high comp rotors and am very afraid of detonation.

 

Karack... the one person that hit 12PSI, that you ported the wastgate within limitations of the stock flapper, did he experience any bad boost creep or anything different?

So, if I don't port all the way to 40mm... say to like 25mm-30mm then I shouldn't have a problem?

 

I ported to 31mm and it's *slightly* angled, not 90 degrees to the runner. I am at 6 psi all day long in any gear! I also have the REVII. I was expecting higher boost, but didn't get it.

 

Prepare yourselves for a noob question. I don't drive a turbo car so i have reasons. What exactly IS boost creep? What causes it and why would porting the wastegate improve anything?

 

Bama420: Wastegate allows for excess exhaust to be released. If the wastegate is small, there's not as much flow so more exhaust is unreleased and fed back through the turbo causing increase in boost. Think about pouring water in a funnel; too fast and you overflow but if you widen the narrow end, you can pour much faster right?

By the way, I don't have mine ported with a 3" turboback, and I'm not getting any boost creep.

 

creep is a slow increase in boost because the wastegate is not bleeding off enough exhaust. porting the wastegate allows more exhaust flow when open, thus decreasing the likelyhood of boost creep.

 

Really? restrictive intake perhaps?

 

Actually, bang on. I haven't put on my GReddy intake yet so not sure if I'll creep with that on.

 

i have a t2 full 3inch exhaust 680 injectors and when i put the stock line from the turbo to the wastegate i boost 13 psi all the time