I ran 9lbs on a t70 with the stock 550's and a walboro, car ran fine pulled hard as **** and I was in the 12's a/f... then I went with the 1600's in the sec and was less paranoid.. on the stock turbo it spooled instantly off the line, an ebc will let it reach boost faster, but it will still creep if its creeping now..

 

OK so I have about the same amount of boost creep on my car. shows 12 psi on my Rtek. I have the fuel to deal with it so I'm not really worried about it and my AFRs are obscenely rich. BUT i still want to fix it.

Quick breakdown
walbro pump
4x720 injectors
Rtek 2.0
Racing beat 3 inch full exhaust
twin scroll not hooked up.

So,
Why do I have so much creep? the RB is only supposed to boost to 10psi. Is it the waste gate (stock S4 turbo), or the twin scroll being disconected?

 

******. Is it the waste gate (stock S4 turbo), or the twin scroll being disconected?****

If series four I'd GUESS wastegate. PUll the turbo off and remove the rear plate on the turbo and take a rotary file to the HOLE the wastegate flap covers. Hog it out so the flap just has enough material to rest over the hole. Gut the passage to the hole also.

That might help some. Give it a try.

Odd thread. I can set the manual boost controller to run at 10 psi and I have no LEAN problems. Kinda stock car with 550's and a stock fuel pump. Just lucky I reckon (humor).

Helpful link: http://www.aaroncake.net/rx-7/s4wastegate.htm

I solved the wastegate problem on one of my cars by buying a series five turbo/exaust manifold and having it made into a hybrid. Series five waste gate is a little over twice as big as the series four .

 

i think some people on here are getting the wrong idea. i know what causes boost creep. and i'm not asking how i can solve the problem of boost creep with a boost controller. i'm asking "will it creep above 12 lbs if that's where i set the boost controller at?" for example.....lets say i get a controller, set it at 12 lbs....i get going, it spools up to 12 lbs as soon as it can say around 3500? (correct?) then once it gets to about 4500 (where it used to creep before) will it creep even higher than 12lbs? i hope i'm making sense.
peace

p.s. i do have an fd fuel pump.

 

I believe I read somewhere a statement by NZCONVERTIBLE, the a boost controller can not LIMIT the boost pressure, it can only raise it to a given level.

I think I just wrote that NO, if you buy a boost controller it won't limit the boost level. No way Jose.

It can Raise the boost but can't Limit the level.

 

an ebc will speedup spool time, but if the wastegate is creeping now, it will continue to creep...

 

you sure about that??

https://www.rx7club.com/time-slips-dyno-128/pump-gas-vid-640025/
i believe this guy is running one!?
i think?

 

not sure what j-rat is running. i know he's putting up some large hp numbers tho!!

I like to build for reliability and caution along with power. Anyhting over 350 hp and I would run an external.

 

Actually the Walbro 255 can support ~500hp...

If you think EBC's don't reduce lag then I'd have to doubt your claim that you've used one. One of the big advantages of an EBC is keeping the wastegate closed right up until just before the boost set-point, which makes the turbo spool faster than it would without a boost controller. This is an indisputable fact. Even simple pneumatic boost controllers do this to a lesser degree.

If you see 12psi without a boost controller, than adding one won't increase that unless you want it to. Boost controllers don't cause boost creep.

Very true.

 

Referring to OP: That's the thing though, if you know what causes boost creep like you've said a million times in this thread, then you'd know that the boost controller won't help, unless it's the boost controller that you don't understand. Upgrade your fuel system before you blow up the motor.

PS. Narrowband FTL.

 

I am running a Walbro of course, and just one.

At 490 HP, my injectors are banging away at a lazy 73% duty cycle on an ridiculously low base pressure, so I didnt feel the need to upgrade any further. If I do run low on fuel, I will just add another walbro, in the tank.

Rat

 

hey jrat, what inj size are you running?

i'd think that you'd want to run an aeromitive sometime in the near future.
don't want to hear all that noise from the external?

 

720 primaries and 1680 secondaries.

 

BAM!

 

I ran 1600 and 550 with a walboro and I could still cause it to flood as a safety measure in case the boost crept..

 

I wasn't trying to claim they won't reduce lag at all. I'm saying they won't make the stock turbo hit 15psi any sooner than it'll creep to 15psi with an unported wastegate, as per the original question. And they certainly won't prevent it from creeping any higher, as that's the wastegate's job.

 

That's not true. The EBC keeps the wastegate closed until just before the desired boost level is reached. If the wastegate was operating strictly under spring tension, then it will start opening well before the boost level at which it is designed to be fully open (remember that a spring is not an on/off device...it is analog...).

 

The only way I would see boost creep as a benefot would be if your wanting to keep the pressure up in the higher RPMS in gears 1-3.

I know my stock turbo runs out of breath and drops a few psi below my MBC's mark in the high RPM's.

The boost creep would help keep the turbo going but you still run the chance of spiking or just plain over boosting unless you got that perfect balance between wastegate size and slight creep.

I've never used an EBC so I can't comment on wether that does a better job of high rpm boost control.

 

It does an infinately better job at high RPM boost control.