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-   -   whats up (http://www.mitsustyle.com/forums/showthread.php?t=17791)

Andrew7dg 12-04-2007 12:52 AM
Re: whats up
 
I would stick with pump gas, don't go to E-85 yet, plus isn't E-70 now? RETUNE!

You would need to upgrade the injectors again because the 680cc would get maxed out. You are set up with a good S-AFC and injectors. Leave the system alone for right now. Look at fixing your creep (but with those injectors you can let it creep up to 18-19 psi and be fine if it does), upgrading to a FMIC, Cams, ARP, list will go on.....

Plus if you are thinking about switching to a 6 bolt block, save the money for that.

I might have one available coming this spring, once I remove it from my car.

GsXtUrBo98 12-04-2007 12:55 AM
Re: whats up
 
Quote:
Originally Posted by Andrew7dg (Post 219517)
I would stick with pump gas, don't go to E-85 yet, plus isn't E-70 now? RETUNE!

You would need to upgrade the injectors again because the 680cc would get maxed out. You are set up with a good S-AFC and injectors. Leave the system alone for right now. Look at fixing your creep (but with those injectors you can let it creep up to 18-19 psi and be fine if it does), upgrading to a FMIC, Cams, ARP, list will go on.....

Plus if you are thinking about switching to a 6 bolt block, save the money for that.

I might have one available coming this spring, once I remove it from my car.
i have a 6 bolt block already i just want it cleaned up and then im going to re-use the 7 bolt cyl. head and shit but its gonna cost me 700 for the 6 bolt to be rebuilt and then 1800 or so to swap it at MAP

JET 12-04-2007 01:42 AM
Re: whats up
 
Quote:
Originally Posted by GsXtUrBo98 (Post 219516)
dont get me wrong, it runs good i just would like for it to idle at a higher rpm and it just wont do it for me
Have you tried the idle adjustment screw? There is that and the BISS. You should do a boost leak test too.

GsXtUrBo98 12-04-2007 11:09 AM
Re: whats up
 
Quote:
Originally Posted by JET (Post 219520)
Have you tried the idle adjustment screw? There is that and the BISS. You should do a boost leak test too.
that screw is what i tried and at LSE they did a boost leak test for me.. but what is the BISS??

Pushit2.0 12-04-2007 11:57 AM
Re: whats up
 
base idle set screw.

sleepydsm 12-04-2007 12:39 PM
Re: whats up
 
swap the engine yourself. save yourself the money. blageo23 has a ton of experience and wouldnt mind helping. you should check out his car in person...

niterydr 12-04-2007 12:53 PM
Re: wats up
 
Quote:
Originally Posted by JET (Post 219405)
Boost creep is caused by the wastegate not flowing enough. You will likely have to get the turbo ported and the O2 housing. 205 isn't too bad for low boost, get the issues figured out, then turn it up! Also, if you turn the boost up to 15 psi, it will still creep to 19, it won't make it creep higher.
Yes on needing wastegate work, incorrect on the ability to crank it up down low, here is why:

Most of the time it is an overall exhaust flow issue. The wastegate is getting choaked/can't bypass enough, so most of the time you have to start the boost lower than you'd like so you don't end up overshooting. Severe boost creep (like this car has) nearly makes the damm car nearly supercharged, increase in rpm is an increase of boost, and it says linear* when you are running into a flow restriction.


* It is not directly linear as you run out of compressor efficiency, but with his car it was shooting for 20+psi easily, something I didn't want to do on a smic w/o timing control on a 16g.

Welcome to the forums, glad you figured it out!

niterydr 12-04-2007 12:55 PM
Re: whats up
 
Then again maybe I am 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. 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...

blageo23 12-04-2007 01:20 PM
Re: whats up
 
Quote:
Originally Posted by sleepydsm (Post 219554)
swap the engine yourself. save yourself the money. blageo23 has a ton of experience and wouldnt mind helping. you should check out his car in person...
Thanks for volunteering me! But I would be glad to help if you got a place to work on it. And NOONE gets to check out my car in person until it runs!!! haha

Pushit2.0 12-04-2007 03:19 PM
Re: whats up
 
Welcome again, darn winter now we will fight untill spring....
Here is a car that did the same thing, we did head studs and a AFPR and now its fine running that much boost.
http://img522.imageshack.us/img522/4...reepgj1.th.png
~John

JET 12-04-2007 07:49 PM
Re: whats up
 
Quote:
Originally Posted by niterydr (Post 219562)
Then again maybe I am wrong
From my experience, yes, you are wrong.

Quote:
Originally Posted by niterydr (Post 219562)
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.

Quote:
Originally Posted by niterydr (Post 219562)
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 12-04-2007 10:09 PM
Re: wats up
 
Quote:
Originally Posted by JET (Post 219405)
... 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 12-04-2007 11:29 PM
Re: whats up
 
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 12-05-2007 12:03 AM
Re: wats up
 
Quote:
Originally Posted by Pushit2.0 (Post 219643)
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 12-05-2007 08:54 AM
Re: whats up
 
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 12-05-2007 12:03 PM
Re: whats up
 
Quote:
Originally Posted by MustGoFaster (Post 219672)
... 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 12-05-2007 12:44 PM
Re: whats up
 
Quote:
Originally Posted by JET (Post 219629)
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 12-05-2007 03:21 PM
Re: whats up
 
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 12-05-2007 03:27 PM
Re: whats up
 
MAP is having a special on FPR. Buy it now!

GsXtUrBo98 12-05-2007 03:35 PM
Re: whats up
 
Quote:
Originally Posted by blageo23 (Post 219710)
MAP is having a special on FPR. Buy it now!
ya i talked to them today and they said something like 130


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