Problems keeping boost down
 

I have a stock s4 turbo, but i ported the wastegate to the edge of the stock flapper, i didnt think it would give me any trouble but i hit boost cut in 3rd gear every time. I knew the stock turbos had problems, but i didnt think they were that bad... Could it be anything other than too small of a wastegate? Can improper ignition timing effect your exhaust output?

I have stock engine with cone filter intake and gutted cat.

porting the wastegate won't make it not hit fuel cut. It will just keep it from spiking to insane levels (15-20psi). Uncorking the emissions is enough to raise boost. You need a fuel cut defender. Get an Rtek 1.5 http://www.digitaltuning.com/index.p...age=1&ecu=S4T2

I have an S5 turbo and I ported to the edge of BOTH flappers. I'm hitting 15psi+ by second gear.

Pisses me off

keep your foot off of the floor. the cold weather causes the extra boost levels. i am hitting 14 psi in my stock s5 with no fuel cut defense, but i am not hitting fuel cut due to the extra fuel i am putting to the engine. it is great, 250 rwhp yea baby! bring on the cold weather.

I call BS to the above post. It doesn't matter what the weather is like, the stock ECU will stop sending fuel to the rear rotor (I think) at 8.6 PSI, or whatever it is. There is no way you are actually hitting 14 PSI unless you have some form up fuel cut defenser.

Sure there is, a MTBI... DUH!!!

Whats a MTBI you ask. A madd tyte boost increaser, of course :rolleyes:

ok this is gunna sound like a noob'er question then the 1st post.

the wastegate where exactly is it? i have a s5? do i take my turbo off to get to it???

Is it correct saying the bigger you port them the more boost it will give u???

If you only port it a little will it only slightly up your boost????

do u have to have a fuel cut if you are running say 8 to 10 psi boost????

my s5 currently runs 4 to 5 psi on a s4 ecu??? can i simply take the 13b t s4 ecu out and connect a s5 13b t????

what are the main differences between the s4 13b turbo and s5 13b turbo engine and turbo???

Thanks guyz

From OZ

hmmmmm. I didnt think you could run a S4 ecu on a S5.. maybe im wrong. Anyway you got it all backwards mate. Put another shrimp on the bar-b.
The wastgate is a valve that open at a certain boost level to stop boost from increasing by by passing the turbine wheel and sending the exhaust gases straight down the exhaust.
The bigger you port the wastegate the less boost it will give you.
If you only port it a little it probably wont do anything.
A fuel cut is a built in factory protector. We get a little box that plugs into it pressure sender loom that tricks the ecu so we can run more than 8 psi boost ( other wise the ecu would cut fuel ).
stock you s5 should be running 7.5 psi or if its a S4 5.5-6 psi. The Ecu on a S4 does not controll the boost. It is a preset wastegate actuator that opens up a 5.5 psi. The S5 have an electronic boost controll soleniod that the ecu controls to regulate boost.
from across the ditch. I hope we win the leauge. im not holding my breath tho

Anyone have that chip? Sounds pretty cool thinkin about getting one. :noyes:

I have the Rtek7 2.0, and it is great for the money. If you are looking for some cheep engine tuneability I would reccomend the 2.0. It has alot of customizable things like injector choices(550, or 720) controll of the fuel map up to 14psi, timing tables, dataloging and stuff like that.

howabout those hybrid turbos? Do you have good luck with the s4s keeping the boost right where its supposed to be?

yes the rtek chips are great, I would suggest them to anyone, and to the first post, if you have a good exhaust and intake(Do you have a better TID also?) porting the stock wg to the edge of the stock flapper isnt gonna be enough you need to make it alot larger than that!!!!Also to this guy^^^ The bnr hybrids are good i hear and thats what i plan on getting, they port your stock wg out for you so you dont have to worry about it if you get that....

Justin

stop spreading mis-information
do you know what a wastegate is, or what a wastegate does?
spiking is from a bad vac line / weak wastegate disgnal, whatever and something that causes the wastegate to open not fast enough

dont get a rtek 1.5, 1.7, 1.8, whatever without having some sort of fuel management
the rtek does not give you a new fuel map, doesnt make you run richer

all the 1.5 is is a FCD, it doesnt give you more fuel. any other FCD will do the same job and you will blow your motor up all the same

you need something like a f-con or rebic lc in order to get more fuel.

hm that rtek chip is something nice. I will have to keep that in mind. Version 1.7 here I come!

i think he ment creeping not spiking but i knew what he ment. The rest is right tho. setting a boost controller to 10 psi with a ported wastegate is still gona hit fuel cut.

perhaps he got it confused with boost creep....

Porting the wastegate to the size of the original flapper only goes so far...In the case of S4, not very far at all. You need to port past the size of the flapper:
http://www.aaroncake.net/rx-7/s4wastegate.htm

Thanks. Luckily, i'll be spending lots of time in the garage soon because i'm moving my motor to a different chassis. It'll be a perfect time for me to either find an s5 turbo or weld on a bigger flapper. I still find it amazing that the stock wastegate sucks that much...