nu-rx7junkie

iTrader: (1)

Ok I finally got my car running and have been driving it. But the work never ends. I have noticed that on warm days the car boosts 7psi all the time since I ported the wastegate. S4 turbo and 87TII engine. 7psi is not the issue. But since the temps dropped here it will creep or spike to 10-12psi under WOT.I did port the wastegate bout 30mm. And it has helped. I replaced all vacumm lines and i hear about the pills and check valves IN the lines? I have no idea about valves and restrictor pills shoved into the vac lines? If I didnt put the restrictor pills back into the vac lines could that cause boost creep? The wastegate to compressor line I did replace, but I know I didnt put a pill in it cause I didnt know about them. The twin scroll?Could that cause boost creep? If I just wire it open would that fix it? I have read lots on here about boost creep but everyone pretty much says port the wastegate and I have. I did do a large street port and I do have 3" exhaust, and cone filter on afm. Any ideas would be great thanks

The Wankler

iTrader: (14)

Restrictor minimizes the bucking you get from the drastic signal sent from the Boost sensor to your cpu. Nothing to do with boost creep

Try porting that son of a bitch BIGGER. First I went 34mm and got major creep. Rotaryshack went crazy big, no more creep. My Greddy EBC works awesome.

LARGER PORTING!

SpeedOfLife

iTrader: (16)

"I did do a large street port and I do have 3" exhaust, and cone filter on afm."

That's probably why you still creep. Have you welded a new flapper onto the wastegate arm? That's the recommended way to allow you to make the port much bigger so that you don't run into this problem.

arghx

iTrader: (3)

restrictor pills affect the boost pattern on a sequential FD, but they don't have much of an effect on an FC.

Controlling boost can be hard when you've got a ported motor and a big exhaust. I had a decently ported s5 wastegate and it still creeped when it was cold.
You are running no boost controller right?

7dust

iTrader: (14)

I ported the wastegate to the edge of the flapper and it still creeped.

What I did to fis the problem was to remove some material from the backplate behind the flapper. Someone with a milling machine could do a better job but just the work I did with a die grinder fixed the problem. Realize that this was in addition to wastegate porting.

Best part is that you can likely do it without pulling the turbo and just removing the downpipe to expose the bolts holding the backplate on.

This allows the wastegate to travel farther.

Anyhoo, worked for me.

nu-rx7junkie

iTrader: (1)

I did weld on a larger flapper. the flapper is 34mm if I remember correctly, and I did take a little bit off the back plate to let the flapper open a bit more. And my wastegate hole was way bigger than the stock flapper. Ok So bigger wastegate port?To what size ? 40mm?50mm? How about aftermarket? Weld it up to the manifold and the dn pipe and shutoff the stock wastegate hole? Then I could chage the spring for boost?hmm?

(And fyi dont think it matters but my car HATES cold weather starting takes a few tries to start and like half hour to warm up does everyone run stock t-stat? or a cooler one, mine is a 185 degree i believe, and never shows more than a 1/4 up on temp guage.)

SpeedOfLife

iTrader: (16)

OEM thermostat is HIGHLY recommended. Apparently many people have had problems with any other thermostats, even if they say they open at the same temperature as an OEM one.

As for the wastegate, the bigger the better. As long as it still works properly, you want it as big as you can make it (within reason). For the stock turbo I'd bet 50mm would be plenty. See Aaron Cake's writeup, he has tons of experience and he probably notes a good size in there.

freemanrx7

Try and find a used s5 turbo and manifold. I bought a very used s5 turbo and just used the hotside then combined it with my s4 cold side. You will also need an s5 turbo manifold. This combo also gets rid of the twin scroll.


Port that bitch and be done with it!!!!

arghx

iTrader: (3)

are you throwing any codes? (do a search on this). you could have a bad water thermosensor and it's thus not injecting enough fuel for cold starts. the ecu will default to a "warm start" condition and inject less fuel if your thermosensor is bad

nu-rx7junkie

iTrader: (1)

Ok ill check in to the codes and see whats there.

Ill get a mazda tstat and see if if takes less time to warm up to operating temp.

And I will pull off the turbo again and see how big i can go. Any shape matter? or just size and function and sealed? Thanks Oh and i guess im gonna port it further to 50mm!and see what happens guess that would help if i ever wanna raise the boost and mabey a dash of nitrous!!!!

nu-rx7junkie

iTrader: (1)

Ok ported the wastegate to the extreme limits and no more creep problems! Its pushing steady 5-6psi. And dont know what i did but no more starting problem so far? Think i need new connector for the thermo sensor or just fipg a dab on it and it wont move.

The Wankler

iTrader: (14)

Good to hear. Overporting it made my creep go away.

nu-rx7junkie

iTrader: (1)

cAR IS NOT BOOSTING WELL.
Hits 2-3 psi then drops to 0 or -3 or -5 ?????? Only hits boost on highway to 5 psi im on stock turbo .
Any ideas????????

freemanrx7

Your wastegate could not be operating properly.

nu-rx7junkie

iTrader: (1)

Cool Gonna Check It Asap Shitty Thing Is Im Ready To Head To Track Tonight!!!!! My First Trip Maybe A Dud????

polito Racing

iTrader: (1)

ok guys i got a question. why areyou guys porting the wastegate?

freemanrx7

We are porting the wastegate @ the wastegate!

You know the flapper door inside the turbo hotside.

polito Racing

iTrader: (1)

i know what the wastegate is. I just want to know the reason why you do that.

gkarmadi

iTrader: (20)

I think the reason is the topic of this thread...

Once you get your 87t2 runs (and if it is stock), then you know why you need to port the wastegate.

1987tIIc

iTrader: (1)

to reduce boost creep lol

polito Racing

iTrader: (1)

ok, i was just curious everyone is wanting to get more boost but you are trying to decrease it for what i understood out of it. i was just wondering if besides the creeping boost there was something else to it. just trying to learn i guess.

SpeedOfLife

iTrader: (16)

Unless you port the wastegate past the flapper it shouldn't reduce boost, it will simply help keep you from creeping.

nu-rx7junkie

iTrader: (1)

Ok I fixed the no boost problem and got to run at the track. The dash pot system is acting up , so i disconnected it and volia!!! Boost again. But i have to practice launching. I was bad. my best time was 15.3 yuck. And all my other times the car wasnt boosting. OH well. Thanks Oh I HAVE NO NORE BOOST CREEP.Love this place.

jcosta

What are you guys using to monitor your pressure?

I have put Bonez intake and downpipe and I am getting major boost creep.

Anyone in the Raleigh, NC Area that could help me pull my turbo and port the wastegate?

nu-rx7junkie

iTrader: (1)

Boost Guage