whats up

[JET]

Then again maybe I am wrong

From my experience, yes, you are wrong.

I only tune cars for a living and have set the boost on a 500+ of them by now... He was having a boost control issue, aka his wastegate wasn't flowing, aka he needed to address it with the ability to flow more air. If you give the compressor wheel a running start (aka more boost down low/allowing the wastegate to remain closed longer) why WOULDN'T it go higher? Again, Justin, I understand what you are saying, but his car was going higher on its own will, its a pretty common problem actually, something I get to deal with on 1/2 the dsms I work with.

You need to think about this a bit longer, Swanny. Having the boost set higher does not make the boost creep worse. The problem is an inability for the wastegate to flow enough out of it and the exhaust is flowing too much. This almost always comes from an upgrade of the exhaust, but no upgrade for the WG path. This causes an imbalance that the stock car doesn't have. This is easily fixed by porting of the turbo, and if it is severe enough, porting of the O2 housing, or an O2 housing upgrade.

Unless we have a proper wastegate on it (or a good boost leak) the car will build 20+psi by redline easily, yes it will hold, but that overall boost spike will continue to rise until you run out of efficiency.
I really doubt we would tell a customer to keep the boost down for shits and giggles...

The problem he is having is NOT a boost spike. He has boost creep, 2 totally different issues. Boost spike is shown on John's graphs, that is the spike when the boost first hits. A boost spike will get worse as the boost is turned up. Boost creep is the ramping up of boost also shown on John's graphs. I have fixed many cars with boost creep issues just by porting, many people on here have used them and they work fine. Porting will fix his problem, period.

[Pushit2.0]

... Also, if you turn the boost up to 15 psi, it will still creep to 19, it won't make it creep higher.
The point of my graph disproves this idea, on this set up atleast, I am sure it can go either way.
So how do you like the forum so far?

~John

[JET]

Tuning can obviously change boost creep also. If you tune for more power (at the point boost creep starts) then even more exhaust will go through the exhaust and make the boost creep worse. Try only turning up the boost on a car once, I bet it doesn't go higher for boost creep. I was fighting this with my car for a while, those were the first turbo's I ported. I was logging on my AEM and the boost creep did not get worse when I turned up the boost. I have seen the same results first hand with probably a dozen cars, several are members on here.

I would like to hear Shane or Mo chime in on the subject.

LSE boys, don't take my posts the wrong way. Technical banter on here doesn't come around often, so this is interesting. I am not trying to bash you guys or anything. What you are saying is the opposite of my 1st hand experience and the opposite of the physics I can come up with on the subject.

[GsXtUrBo98]

The point of my graph disproves this idea, on this set up atleast, I am sure it can go either way.
So how do you like the forum so far?

~John

im likin it alot!! all this input is great and i didnt know that my car would set up so many arguments just about boost creep and fixing the problem... ha ha

[MustGoFaster]

I've seen it go both ways. On cars with big exhaust (3" all the way or similar) and stock waist gates it tends to be the higher you set it, the higher it creeps type situation. Josh's $800 Talon worked this way when we put the exhaust on it. Crept like a mofo till we did something to fix it (ported turbo, or external dump, I forgot what we did)

We had an Audi in here that was similar, it would creep to ~21 on straight WG setting, with the inital at 18 it would creep to 24, about all they wanted to run.

My GVR4 had a 14B, with an external dump O2 housing, it would boost creep if it was "cold" outside (50F) with the boost low, but not when it was warm (65-70). I could also just set it higher and not have issues, but this is when I first got it running so I wan't comfortable with it yet.

It seems to me, On cars where the creep goes away when you turn it up, the WG itself isn’t big enough. On cars where it creeps higher the higher you set it, there is a WG flow path issue.

[Pushit2.0]

... It seems to me, On cars where the creep goes away when you turn it up, the WG itself isn’t big enough. On cars where it creeps higher the higher you set it, there is a WG flow path issue.

That seems to be a good way to put it. JET on the tunning end of it, retarted ignition timing will make a turbo creep, so adding ignition timing if you are not at MBT will make the turbo creep less. This might help with to small of a waste gate or a waste gate flow path issue but if thats the problem turn the boost up more, or fix the flow issue. So we now move all the post with tech to the tech section?

~John

[niterydr]

From my experience, yes, you are wrong.



You need to think about this a bit longer, Swanny. Having the boost set higher does not make the boost creep worse. The problem is an inability for the wastegate to flow enough out of it and the exhaust is flowing too much. This almost always comes from an upgrade of the exhaust, but no upgrade for the WG path. This causes an imbalance that the stock car doesn't have. This is easily fixed by porting of the turbo, and if it is severe enough, porting of the O2 housing, or an O2 housing upgrade.



The problem he is having is NOT a boost spike. He has boost creep, 2 totally different issues. Boost spike is shown on John's graphs, that is the spike when the boost first hits. A boost spike will get worse as the boost is turned up. Boost creep is the ramping up of boost also shown on John's graphs. I have fixed many cars with boost creep issues just by porting, many people on here have used them and they work fine. Porting will fix his problem, period.


My thoughts exactly he has to work the wastegate housing by increaseing the size of the bypass OR a higher tension spring.

BUT is is a flow related restriction, so if we turn the boost up down low, it will continue to creep as the wastegate isn't displacing enough air. I have seen this in HUNDREDS of cars. You can starve off a creep by tuning ignition timing, having the boost come on lazy, or decreasing wastegate force up top (ebc applications only). On this setup, he should just port the turbine housing/upgrade the 02 and call it done.

That is my point is he can't just set it to 15 and expect it to stop at 19, it doesn't work like that.

[GsXtUrBo98]

ok to all of you.. you all have very good points of view and when it comes down to it i think the turbo being ported and a diff o2 housing is in order for me, plus i think im going to do a fuel pressure regulator

[blageo23]

MAP is having a special on FPR. Buy it now!

[GsXtUrBo98]

MAP is having a special on FPR. Buy it now!

ya i talked to them today and they said something like 130