ZeroBanger

I misread your post. The point im making is that the midpipe alone will not give you boost creep. In my world boost creep doesn't exist. I think alot of it is exaggerated, like someone sets the power fc to .80 and they get .84 and call it boost creep.

and yea I have had 2 sets of turbos, 1 straight through exhaust and a semi-restricted exhaust and no boost creep, so I dunno, I guess I got a lemon.

XSTransAm

just to clear a point up, thats a 4th gear pull... in 5th gear on the road i do see alot more boost at redline

edit: not that ive redlined it in 5th

TireSmokin7

I believe the exhaust system has the largest portion of the boost creep equation. However, if your intake tract is restricting flow through the motor the exhaust doesn't have the same amount of CFM (cubic feet per minute) of gasses to release. Now if you add a large stock mount intercooler and remove the second set of butterflies in the throttle body with a free flowing exhaust you should be able to flow enough CFM to over power the stock waste gate. Simply because you’re flowing more air.

Steve

rx713bt

iTrader: (4)

You are so right. It depends mostly on exhuast system. The other stuff like intake has an effect but not as much.

Also, the factory pills can have an effect.

For instance, my buddy installed a full exhuast with a bunch of other mods. He has over 15psi after switchover. I removed his wastegate pill and the reaction time for the gate opening is much faster. It reduced his boost pressure on lower gears to about 11-12 psi.

Since he has a Haltech, his boost setting will react differently than stock ECU boost settings.

-Jeff Ho
93' R1

RX7WEEE

iTrader: (16)

Now are all of you running an upgraded ECU?
Or do some of you have like a DP and MP with out one?

jpandes

Now that I got my smog issues taken care of. I'm gonna get a mid pipe too..

XSTransAm

Im pretty sure that everyone who modifys their car has an upgraded ecu

saxyman990

huh? How do you figure? I disagree. I know TONS of people who have various engine mods without an ECU. Most people start modifying by adding DP, CB, and intake well before they get a new ECU.

However, MPs are typically a later upgrade and most people that switch to a MP already have an upgraded ECU. A good amount of people have trouble with creep using a MP, which is a BAD thing on the stock ECU. But, if you can keep the boost constant and under 10psi, then you'll be fine on the stocker.

Rob

XSTransAm

I think the two mod rule comes into play here... like dp intake, but as soon as you try to make real power you NEED an ecu. but hey if you think otherwise go ahead, its not my engine

I did have my dp, cat back and intake before my ecu... car was fine. would I have gone further without ignition and fuel control? hell no!

saxyman990

The three mod rule has been totally disproven. As long as you keep the boost below 10psi, the stock ECU can handle all of the bolt-ons. This has been known for years. Take a look at Wade Lanham's site:

Myths: 3 Mod Rule

The three mod rule is a good general guide for newbies who may not know how to control boost. But it is a fallacy as long as you can keep the boost at stock levels.

But again, a MP usually introduces some uncontrollable boost creep, which would be BAD on the stock ECU. I was just addressing your statement that everyone who modifies their car is running an ECU. Which (most people here will agree with me) is not an accurate statement.


Rob

spoolin1012

iTrader: (2)

Can someone exsplain to me what a boost creep is, i've heard of it but I dont understand.

Zoomspeed

Its when your waste gate can't vent enough to keep the boost level down. When that happens you get a slow rise in boost at WOT.

This ends up being a problem when people open up there exhaust becasue there is more flow through the turbos hence the wastegate has more it needs to vent.

Larz

Or boost spike is when it just jumps up. Like from 10 to 16. A big *** waste gate can prevent this.

lopedl

iTrader: (1)

You sure the catless isnt purple and the stock cat is red. Cuz if its the way you said it the stack cat is making more boost than the catless.