Midpipe Boost Creep Avoidance
 

I have just seen Greddy's Pop Off Valve, will is a mechanical device that you can weld to the intake elbow and set to a predetermined amount of boost. Now i know if I replace the factory cat with a off road midpipe, i will have boost creep, does anyone know if it is possible to control the creep with the pop off valve from greddy. I really hate to spend 500 dollars for a stupid hi flow cat when a straight stainless steel midpipe i can get for 130 on EBAY will do the fix, and will be used once i blow my motor and go single.

My question is is this possible, to avoid the creep without posting the wastegate located on the turbo.

IF you are not putting on the midpipe until after you go single, you will not have boost creep.

i have midpipe and needle valves and no boost creeps.

i want to put it on with my singles too. Also, what is "needle valves", i dont think i ever heard the term

No offense, but it sounds like you need to do a lot more research. Going single is a major change and involves upgrading a large amount of systems (fuel injectors, fuel pump, standalone ecu - tuned properly, etc.). Spend some time reading through Robinette's and ScuderiaCiriani websites. You will learn more about the process of upgrading your car and some of the common upgrades and mods (such as needle valves).

Good luck.

lol, i have done alot and know alot about my FD but i havent heard of needle valves either :p:

could someone explain? do they go by a different name also?

its pretty much the homedepot boost controls

easiest way to eliminate boost creep is just run more boost like 14lbs. problems comes when guys wiht midpipes try to run 12#

yeah ive never heard needle valves i think we should standardize it as the home depot boost controller

except that i've never been able to actually find the needle valves at home depot---i find a hardware store much easier to locate things at. i hate home depot its too hard to find things.

With mods that increase 'flow' you will eventually have to control your boost levels(keep them down). The needle valves worked really well me until I added a hi-flow cat(damn CA tree huggers!) to my CAI, dp, cat-back, & ic. once I added the hi-flow cat i was getting mad boost spikes and boost creep.

I had to add restriction back into the system. What I did was add a restrictor plate in between the hi-flow cat and the cat-back. A restrictor plate is simple a 3"x3" piece of metal with a 2 1/4" hole in it, thus reducing the diameter from 3" to 2 1/4" and reducing exhaust flow.

You can just buy one of those electrical junction box covers for $1.09 at Ace hardware and use a dremel/drill to cut the holes. Simple.

But, if you want the best solution and to get every ounce of power form your motor, you need to port your wastegate. This involves removing and dismantling the turbos. Then you will have to enlarge the hole underneath the wastegate flapper door. I recommend machining it. Do a search on porting the wastegate. There are some much better how-to's along with pics.

I chose not to do this because it was too much work and a bit too intimidating. I called a local shop and they quoted me $600 to do the job.

I hope this helps.

John

I spoke with Ari of Rotary Performance about this when I was experiencing boost creep with an open exhaust.

I was creeping to 15 psi while trying to run 13psi. I asked him if I could just turn the boost down to 10 and creep to 12, because of the 2 psi differential.

He explained that regardless of what boost you're trying to run, you'll creep to the same value. This is because boost creep is solely a function of lack of backpressure combined with an inadequate (too small) wastegate which can't divert all of the necessary exhaust flow away from the turbos.

I did a little experiment--turned off my profec B (thus running minimum boost, 7 psi) and held 7 on the first turbo, then began creeping with rpm as the second turbo came on, hitting 15 psi at redline.

Bottom line is this: port your stock wastegate, or run a cat, or go single turbo with a bigger wastegate, or blow your motor. Midpipes aren't all they're cracked up to be with the stock twins; I made 368 at the wheels with a high flow cat and original stock twins. I would hope that figure is high enough for all of you horsepower junkies :).

if you've actually done or read about the home depot boost control mod then you'd know what "needle valves" are. Especially when you're in a "boost creep" thread. Just my $.02

Needle valves will help with boost *spike,* not creep. See my above post...

I agree...but wouldn't you think that the valves would help him a little if he doesn't even have any types of boost control???

I mean without the valves, I was hitting 1.06 bar by 6500 with just the dp and cb. Now I don't even go pass .85 bar with a 3" open exhaust...

exactly, I can run about 12 on primary if I want, but I can't run less than 14 psi on secondaries now matter what the setting. that is cool with me though, I like to run 15 psi anyway :)

Hello, I'm about to get a rebuild...but i have no mods and will probably get a street port...maybe add a downpipe&cat. But my question is, should i get the wastegate ported even on a non-modded engine? any repercussions?

Thanks!
Edgardo

if you're experiencing boost creeps and boost control doesn't help then yes port that wastegate...

Thanks for the reply! But i was asking about porting the wastegate with no modifications performed?:confused: In preparation for when i do start modding.
Is it harmful to port the wastegate with no mods? What would be the forseen effects.

Thanks.
Edgardo

Nope, go ahead and have it ported. The only downside is if whoever is doing it makes a mistake and ports it a bit too much, cracking the metal casing. Otherwise, it won't affect your boost adversely--you won't see a difference at all, unless you run a midpipe in the future, when it will keep your boost manageable.

Cool, thanks GoodfellaFD3S!
FWIW Rob at Pineapple Racing will be doing my rebuild.

Laters!
Edgardo