Boost Creep (oldman read this)

[~laser_craver~]

I will try the test with the actuator off.... But i need to get an alternator.. I went to napa today and looked and they want $167 bucks for one!WTF

 

[bastarddsm]

Not only this is uncalled for, you're incorrect. Hitting fuel cut at 19psi is a clear indication something isn't right, especially with the stock fuel system, that something is usually boost leaks. Daren_p has been right on in this thread, I don't think he's the one who needs to get a clue. In any case, whether you're right or wrong, please be repectful of other members in your future posts.

What do you mean fuel cut at 19psi means somthing isn't right. unless your not on the stock fuel system it means you shouldn't be running 19psi becuse your gonna blow shit up. i could get away with 15psi but my car is all stock including the exhaust and airfilter. on a modded car with a good exhuast you ###### can't get by with more than 10 especially in this weather.

either way this guy has boost creep, and the ony way he's gonna get rid of it is experementing with shit till he finds out what works for his car. or maybee he could have searched and found out what other people have done to fix the problem, and not have posted another why does my car boost creep thread. I do seem to remember somthing about a modification to the wasted gate arm that moves the actuator farther in, thus causing the flapper to open farther, usually ending boost creep.

 

[oldman]

What do you mean fuel cut at 19psi means somthing isn't right. unless your not on the stock fuel system it means you shouldn't be running 19psi becuse your gonna blow shit up. i could get away with 15psi but my car is all stock including the exhaust and airfilter. on a modded car with a good exhuast you ###### can't get by with more than 10 especially in this weather.

Once again, like already mentioned many times, fuel cut has little to do with your ability to deliver fuel, it's strictly an air count issue.

either way this guy has boost creep, and the ony way he's gonna get rid of it is experementing with shit till he finds out what works for his car. or maybee he could have searched and found out what other people have done to fix the problem, and not have posted another why does my car boost creep thread. I do seem to remember somthing about a modification to the wasted gate arm that moves the actuator farther in, thus causing the flapper to open farther, usually ending boost creep.

He has possibly two issues here, boost creep and fuel cut but thanks for pointing out the obvious. If you would have carefully read this entire thread or do a search on Laser's posting history, you would have known that he has already done his research and this indeed is a special case.

 

[~laser_craver~]

Yes i have done much research on this topic. I have ported my turbo to everything oldman has ever said to, the only thing i could improve on that area is the hole a tiny bit larger and the o2 housing ported because i havent done that.

 

[tstkl]

Once again, like already mentioned many times, fuel cut has little to do with your ability to deliver fuel, it's strictly an air count issue.


He has possibly two issues here, boost creep and fuel cut but thanks for pointing out the obvious. If you would have carefully read this entire thread or do a search on Laser's posting history, you would have known that he has already done his research and this indeed is a special case.

whats funny is that it supposedly cuts out at 1600 hz or whatever, but I consistantly log much higher than that before it cuts out. and when I lean it out, I still see 1599hz for extended periods (aka its going to more than and comes down to less than at the end) and it doesn't cut out. I dunno what the airflow limit is, but it doesn't seem like 1600 to me. fuel cut is a mysterious thing to me, at least I know Im not getting it anymore. I understand how it works, but I don't get why It doesn't cut at 1600 like its supposed to. maybe its the curse of the 90's again...

 

[unclesam099]

I don't really think that the airflow number has much to do with it because my AFC reads 2700+ on WOT pulls. Your logger can only read up to 1601 or whatever.

 

[this_tsi_8urV8]

I had boost creep on my car aswell. It had 3" turbo back, no cat, and an open air filter box. I had an MBC, then broke, put it back to stock boost, and it still crept, baadly. I had the o2 housing ported, turbo ported, WG area ported, and the flapper increased to 34mm. I tested the actuator it was fine, so I left it be. After the work was performed, the car came back just fine. NO CREEP @ all. Therefore, I think increase the flapper, and port the o2 housing. If you do not have your exhaust manifold port it, might as well port it since its out. Good Luck.

 

[~laser_craver~]

I think im going to try to port the o2 housing some and the wg hole a little more.

 

[bastarddsm]

Once again, like already mentioned many times, fuel cut has little to do with your ability to deliver fuel, it's strictly an air count issue.


He has possibly two issues here, boost creep and fuel cut but thanks for pointing out the obvious. If you would have carefully read this entire thread or do a search on Laser's posting history, you would have known that he has already done his research and this indeed is a special case.

scince you fail to listen i'll try again. Like everybody knows fuel cut occurs when the air flow meter registers a certain amount of air, this amount is greater than a stock car should ever use. the purpose for this is keep you from blowing you car up, when somthing like a wastegate fails or someone pulls the hose off the wastegate for more boost. it can also occur when you have a massive boost leak. There are a few ways to combat this, leve your car stock, get bigger injectors and and a afc to fool your computer into thinking that it is taking in less air, this is not infinite tho. The amount of extra air you can use is proportional to the change in injector size. for example with 550's you can take in about 20% more air before fuel cut. allowing a 20% horsepower increase. theoretically. Also you could have a chip burned with fuel cut removed. but scince his mod list says he has stock injectors i advise against this.

now onto lesson number 2. think of the engine as a airvalve. in stock form it's almost closed. it takes alot of pressure to get a medium amount of air through the engine. in stock form most dsm's will hit fuel cut at about 16psi. Now pretend we add a 3inch exhaust, intercooler, and some cams, basically we just opened the "Valve" lots. now it takes almost no pressure to flow a medium amount of air. So now our little modified dsm hit fuelcut at 10psi.

The airflow through the engine is proprtional to the boost times the restriction to airflow the engine offers. Simply put on the same engine at the same rpm a t25, a14b, a 20g at the same boost are all going to put the same volume of air into that engine. The acutal air mass may change a little bit, but it isn not enough to even worry about. There needs to be about a 50 degree change in inlet temps for a noticealbe change in power.
If you can't agree to that you pretty much retarded.

now onto the boost creep problem. like I said before i would try the modification the puts the wastegate arm farther in increasing wastegate opening. or he could simply put a cat on. before you go bitchin about the 2 hp loss you might experience. don't. a 3 inch cat will flow more air than any 16g car could ever need.

After rereading your posts i really don't think you have a clue on how the fuel injection sytem on these cars work.

 

[larsrya8]

"But when i hit fuelcut it will only cut out breifly then get back in it." From post 4.
That doesn't really sound like fuel cut to me. I've never hit fuel cut, but from what I've read it hit hard... not the more gentle notification laser craver is describing. He's describing something closer to a "stutter" or "massive misfire"...

Laser craver, I too noticed that you have absolutely no fuel upgrades whatsoever, according to your profile. You have a FMIC, MAF-T, a 3-inch exhaust (with unported 1G O2 housing ) and an upgraded turbo. But no fuel! You aren't doing things in order...

Your "partial" fuel cut is probably misfire or something caused by running out of fuel. Do you at least have a logger? If so, how much air is the car reading? What are your injector duty cycles? If you don't have a logger, don't drive your car hard until you buy one. Don't even test to see if your turbo is still creeping.

You've at least rewired your fuel pump... right?!

As for the creeping problem. Your port job on the turbine housing looks great... better than mine on my Evo3. I was worried about creeping to 30+ psi while also trying to not to thin out the housing too much. Mine still creeps, but it's under 20 psi (which is less than I planned on running on the street after I get a FMIC anyway). I'm running the stock flapper and I didn't port the wastegate hole, just the path to it. If you have tried porting the wastegate hole with no luck, you should turn your attention to the O2 housing.

The other option that was suggested was to just add some fuel mods so you can run that 19 psi on the street. You already have all the other mods necessary.

edit: Some other food for thought: He is running a MAF-T. Doesn't the MAF-T need to be calibrated? Maybe that is why he isn't hitting fuel cut, and is instead getting that stuttering.

 

[bastarddsm]

"But when i hit fuelcut it will only cut out breifly then get back in it." From post 4.
That doesn't really sound like fuel cut to me. I've never hit fuel cut, but from what I've read it hit hard... not the more gentle notification laser craver is describing. He's describing something closer to a "stutter" or "massive misfire"...

Laser craver, I too noticed that you have absolutely no fuel upgrades whatsoever, according to your profile. You have a FMIC, MAF-T, a 3-inch exhaust (with unported 1G O2 housing ) and an upgraded turbo. But no fuel! You aren't doing things in order...

Your "partial" fuel cut is probably misfire or something caused by running out of fuel. Do you at least have a logger? If so, how much air is the car reading? What are your injector duty cycles? If you don't have a logger, don't drive your car hard until you buy one. Don't even test to see if your turbo is still creeping.

You've at least rewired your fuel pump... right?!

As for the creeping problem. Your port job on the turbine housing looks great... better than mine on my Evo3. I was worried about creeping to 30+ psi while also trying to not to thin out the housing too much. Mine still creeps, but it's under 20 psi (which is less than I planned on running on the street after I get a FMIC anyway). I'm running the stock flapper and I didn't port the wastegate hole, just the path to it. If you have tried porting the wastegate hole with no luck, you should turn your attention to the O2 housing.

The other option that was suggested was to just add some fuel mods so you can run that 19 psi on the street. You already have all the other mods necessary.

edit: Some other food for thought: He is running a MAF-T. Doesn't the MAF-T need to be calibrated? Maybe that is why he isn't hitting fuel cut, and is instead getting that stuttering.

the maft is probably what is keeping him from fuel cutting if he isn't. if i was the original poster i would at least put my stock airflow meter back on that way it will keep itself from blowing the up. detonation under lean conditions mean pistons go bybye.

 

[gsxtacy]

If anyone here has actually ever REALLY fuel cut in a DSM, you'd KNOW it.

Its usually right in the Fattest, most loaded up part of the power curve. It feels like you just had a blowout, or hit a huge pothole!!

Stuttering, missing, bucking and hesitating are all problems more related to boost leaks, improper spark plug gap, or like said above, not calibrated MAFT.

I am here for the the Boost Creep resolution though, I still say its the Actuator or the Flapper. Did you get any debris in the flapper pivot when you were porting it and now it binds up? Its right there, I know you'll get it fixed. We're all here for you.

 

[~laser_craver~]

Ok, I havent done jack crap to my fuel delivery at all. I know I know bad bad bad, but everything ive gotten was really really cheap got hella good deals on all of it. Next thing i get is fuel mods dont worry. And i hardly ever drive the car, i dont get my liscence till august.

The fuel cut or w/e im hitting does it hard likei hit a pot hole. But if i keep my foot in it, itll buck and hit like it did originally and then itll get back in it.

My boost will hesitate at 10 psi then climb to 20 and i hit the fuel cut. Im going to port the o2 housing and wg hole just to make sure thats all over with. I am also going to do another boost leak test just to make sure there aswell.

My MAFT is at 480cc base injector size and the rest is zero'd out.

Maybe i should just take a video of what happens when i get on it in 3rd.

If i only give it like 2/3rds throttle itll hold 12psi all the way to redline, with no fuel cut or anything.

 

[~laser_craver~]

Ok i got the fuse so hopefully that will fix my electrical bs. Would you guys want me to post a video of what happens while im accelerating?

 

[larsrya8]

Ok i got the fuse so hopefully that will fix my electrical bs. Would you guys want me to post a video of what happens while im accelerating?

Yeah I could host it for a while.. at least as long as necessary. Wanna e-mail it?

 

[bastarddsm]

that shound like fuel cut to my as your describing it. and you are hitting it EXACTLY AS YOU SHOULD. With your setup you should probably hit fuel cut at like 15psi. you don't have a boost leak problem. get the boos under control and set it to 12 and your car will run great.

 

[~laser_craver~]

Thats the problem, Ive tried like everything in the book to help get rid of the boost creep and tis still here. The only thing left is a ported o2 housing, a tiny bit of porting on the wg hole, or go external wg. When i get that electrical bs fixed ill take a short video of what happens when i mash it, when i give it 1/2 throttle, and mashing it with the wg actuator un hooked.

 

[oldman]

scince you fail to listen i'll try again. Like everybody knows fuel cut occurs when the air flow meter registers a certain amount of air, this amount is greater than a stock car should ever use. the purpose for this is keep you from blowing you car up, when somthing like a wastegate fails or someone pulls the hose off the wastegate for more boost. it can also occur when you have a massive boost leak. There are a few ways to combat this, leve your car stock, get bigger injectors and and a afc to fool your computer into thinking that it is taking in less air, this is not infinite tho. The amount of extra air you can use is proportional to the change in injector size. for example with 550's you can take in about 20% more air before fuel cut. allowing a 20% horsepower increase. theoretically. Also you could have a chip burned with fuel cut removed. but scince his mod list says he has stock injectors i advise against this.

For the most part, this is correct.

now onto lesson number 2. think of the engine as a airvalve. in stock form it's almost closed. it takes alot of pressure to get a medium amount of air through the engine. in stock form most dsm's will hit fuel cut at about 16psi. Now pretend we add a 3inch exhaust, intercooler, and some cams, basically we just opened the "Valve" lots. now it takes almost no pressure to flow a medium amount of air. So now our little modified dsm hit fuelcut at 10psi.

Hold on, let me grab my pen and paper. Hitting fuel cut at 16psi in stock form and 10psi slightly modded? Are we talking about your N/T with turbo? This is the first time I have ever heard such statement being made, where are you getting your numbers from? Something is seriously wrong with your car.

The airflow through the engine is proprtional to the boost times the restriction to airflow the engine offers. Simply put on the same engine at the same rpm a t25, a14b, a 20g at the same boost are all going to put the same volume of air into that engine. The acutal air mass may change a little bit, but it isn not enough to even worry about. There needs to be about a 50 degree change in inlet temps for a noticealbe change in power.
If you can't agree to that you pretty much retarded.

Retarded? You have already been warned and asked nicely to be repectful of other members, please take the warning seriously for your own sake.

Noticeable power is not what we are about here, the fact is any change in intake temperature will change air mass whether it's noticeable or not by your butt dyno. The amount of intake temperature difference between different turbos on the same setup at the same psi depends greatly on the boost level and the efficiency range of the individual turbos. When boosting at 12psi, T25, 14b and 20g will flow pretty much the same since 12psi is well within the efficiency range of all three turbos, 20psi in the other hand is a completely different story.

now onto the boost creep problem. like I said before i would try the modification the puts the wastegate arm farther in increasing wastegate opening. or he could simply put a cat on. before you go bitchin about the 2 hp loss you might experience. don't. a 3 inch cat will flow more air than any 16g car could ever need.

Adding restriction to your exhaust to solve boost creep is not only retarded (not saying you're retarded, it's a sign of defeat.

After rereading your posts i really don't think you have a clue on how the fuel injection sytem on these cars work.

If you're butt hurt about being warned for flaming, take it up with me via PM, I think you have hijacked this thread long enough. Sorry about the off topic laser.

 

[~laser_craver~]

No problem. Mind directing me to a walk through or a how to on the wastegate actuator arm mod so it opens further.

 

[daren_p]

Thats the problem, Ive tried like everything in the book to help get rid of the boost creep and tis still here. The only thing left is a ported o2 housing, a tiny bit of porting on the wg hole, or go external wg. When i get that electrical bs fixed ill take a short video of what happens when i mash it, when i give it 1/2 throttle, and mashing it with the wg actuator un hooked.

Have you tried running it without the actuator connected yet? This will tell us if its actuator/mbc related or something else. I have seen all the porting you've done on the turbine housing so I don't think its your issue. If you are still running the stock wg hole, I think either that or the fact that you still have the 1g unported O2 housing are causing the issue. Let us know.

 

[oldman]

Have you tried running it without the actuator connected yet? This will tell us if its actuator/mbc related or something else. I have seen all the porting you've done on the turbine housing so I don't think its your issue. If you are still running the stock wg hole, I think either that or the fact that you still have the 1g unported O2 housing are causing the issue. Let us know.

Yea really Ryan, unhook the arm and test run already, the result can tell alot. I don't know how to make the actuator arm extend longer, maybe bastarddsm can provide you with the link that he was talking about. I would just replace the actuator if in fact you can confirm it's the actuator.

 

[~laser_craver~]

Well the actuator actually opens about 30-40 degrees but that isnt enough evidentally. I was just thinking about doing tha tmod so that it would help my problem.

 

[bastarddsm]

Original poster - I don't have a link for the mod i was talking about, some guy on here was trying to sell kits for them. There was a thread I *Think* it was called "Definitive end to boost creep". Basically what it amounted to was moving the waste gate arm farther in on the flapper lever, see attached pic basically go the the hargware store and get a little pin that look similar to the one that the waste gate arm goes on and have some one weld it on farther in on the flapper arm.



Oldman - Like I said before if you run more than about 16 psi on a stock car with a stock fuel system you will hit fuel cut. If your car has a 3" exhaust, no cat, and other basic shit, but no fuel mods you'll hit fuel cut at about 10psi. it's very simple. And what the hell does my n/t have to do with things, I was talking about a standard turbo dsm. But scince you asked, my car has been converted to being equivlent to a bonestock 1g fwd turbo. With exception of the exhaust, and guess what it hits fuelcut at 16psi. Two of my freinds had 1g's both with a 3" exhaust, no cat, k&n, buscher hard uicp, stock injectors, one with a 14b the other a EvoIII16g ( which didn't boost creep), and they both hit fuel cut at 10psi. To sum this all up if he has stock fuel injectors and he is fuel cutting at 19psi it's normal becuase he has too small of injectors. If it was like 7-10psi thats a different story, but not 19psi.

 

[daren_p]

Well the actuator actually opens about 30-40 degrees but that isnt enough evidentally. I was just thinking about doing tha tmod so that it would help my problem.

While 40 deg doesn't seem to be much, thats seems to be how far all the mitsu actuators open and there are plently of people running them without any issues. I tested mine before I installed the turbo and it to opened to about 40 deg & was at its max travel right around 10 psi like you posted earlier when you tested it. Not to make you feel bad but I've actually shimmed mine to make it stay closed longer & not open as much

 

[oldman]

Oldman - Like I said before if you run more than about 16 psi on a stock car with a stock fuel system you will hit fuel cut. If your car has a 3" exhaust, no cat, and other basic shit, but no fuel mods you'll hit fuel cut at about 10psi. it's very simple. And what the hell does my n/t have to do with things, I was talking about a standard turbo dsm. But scince you asked, my car has been converted to being equivlent to a bonestock 1g fwd turbo. With exception of the exhaust, and guess what it hits fuelcut at 16psi. Two of my freinds had 1g's both with a 3" exhaust, no cat, k&n, buscher hard uicp, stock injectors, one with a 14b the other a EvoIII16g ( which didn't boost creep), and they both hit fuel cut at 10psi. To sum this all up if he has stock fuel injectors and he is fuel cutting at 19psi it's normal becuase he has too small of injectors. If it was like 7-10psi thats a different story, but not 19psi.

You need to make up you mind on what triggers fuel cut, running out of fuel doesn't make you hit fuel cut because ECU does not take into account of your IPW, IDC or air/fuel ratio. The purpose of fuel cut function is not to guard against fuel starvation, that is the job of the knock sensor (in a way), many have mistaken stuttering caused by fuel starvation and pulled timing with fuel cut. The sole purpose of fuel cut is to guard against runaway boost (like you stateed in your previous post) so only your maf reading can trigger fuel cut. The air count value that triggers fuel cut is a contant guesstimated value pre-program into the ECU and can not be changed, however this value does not equal to your fuel delivery capacity, in fact it's alot higer. Over the years of helping countless members with fuel cut/boost creep related issues, most do not see fuel cut until low to mid twenties, anything before that is usually a sign of higher than normal maf readings and most of time the problem points to boost leaks. If everyone hits fuel cut when they run out of fuel, there would be no need to log, tune or worry about melting pistons, we can all just turn the boost up until we hit fuel cut. Providing examples of your friends hitting fuel cut at 16psi does not prove anything because we know nothing of the conditions of the cars you cited, however any example of stock cars hitting fuel cut at 22-25psi will prove your theory incorrect if you know what I mean. In any case, if you're insisting that hitting fuel cut at 16psi on a stock turbo DSM and 10psi on a slightly modded dsm is normal, please provide links to any creditable source stating the same because it goes against the accepted common DSM wisdom.