Is it possible to boost creep and fuel cut at same time?

[caseclipsegst]

I know this topic is played out I've searched but please help lead me in the right direction .. Mods.. Rebuilt engine stock internals(2000miles on the clock)16g,Megan o2 housing,2.5 to 3" dp, 3" no name exhaust,gm maft with translator, Walbro 255.. No tuning at this time

I bought the car with a spun bearing so rebuilt the whole engine, ended up putting a 16g and all that and ever since I got her running I've had this problem of when I give it wot the guage will creep up to 20psi and do like a fuel cut type of jerk/bog and won't go no where till I let off the gas .. I have the mbc set to the lowest possible setting.. Mind you that this happens only when wot, now as long as I don't put the pedal down it'll run ok.. I did a boost leak test and found the bov to leak like crazy could this be the biggest cause? Or is it the dreadful 16g/ big exhaust(no cat) deal..

I've had this problem ever since the rebuild and it's time to get rid of it.. It's embarrassing when someone revs up to you and you have to take it ### they will smoke you in their minivan ha

 

[idkiliketurbos]

I'm sure it is just boost creep that is causing you to hit fuel cut. The reason mini vans are smoking you is because you don't have any form of decent tuning (ecmlink, ecuflash) to tune your setup with.

 

[clipto]

Ya with bigger exhaust it allows the turbo to flow more. Your best best get a tune get ecmlink and bigger injectors sence you have a 16g. Once your able to lean it out then you will be good.

 

[grothe3297venge]

Well first off, 20 psi on a 16g with stock injectors seems a little sketchy..(assuming your profile is up to date) Do you have a wideband or anything to monitor your air/fuel ratios?! And I see nothing for tuning of any sort..?

^^^^ always to slow when typing on this damn ipad !!

 

[5150DSM]

Boost creep can definitely lead to fuel cut, as the boost creeps (sorry) airflow increases, when airflow hits the ECU's airflow limit, you hit fuel cut. You could also be running pig rich at WOT because of the leaking BOV, which will cause stuttering, bucking, hesitation, etc...

Geez, I type too slow.

 

[5150DSM]

http://www.dsmtuners.com/forums/articles-tuning-ecu/58403-definitive-piggyback-tuning-guide.html

http://www.dsmtuners.com/forums/art...tuning-guide-beginner-intermediate-tuner.html

A wideband and some sort of logging device will go a long way toward telling you what's going on with your tune.

Along with the basic tuning links above, this thread is very helpful with the MAF-T.

http://www.dsmtuners.com/forums/fre...-you-want-know-about-maf-translator-maft.html

 

[caseclipsegst]

If I was to put a hi flow cat on the exhaust would it help with the creep? I bought the 16g used and I think it is ported but I'm not sure if it is at the wastegate flapper..

Sorry no wide band at this time, that is next on the list

 

[idkiliketurbos]

A cat of some sort might help, but that really isn't something that can be a for sure yes. The best way to solve it would be to get it on a proper tune with some supporting mods to run the boost levels it wants to creep to anyways. Plus, you'll be way faster.

 

[caseclipsegst]

Haven't felt fast since my last gst so what size injectors are recommended for my setup? 550's, 660's?

 

[5150DSM]

Haven't felt fast since my last gst so what size injectors are recommended for my setup? 550's, 660's?

How far do you plan to push the 16G? What fuel? Do you have a goal for the car?
I'd pick up a wideband and datalogging gear before I started worrying about injectors and more boost.

 

[caseclipsegst]

No goal intended really, just something to get up and go when I want it to.. On pump gas

 

[MJBean420]

I got a 16g tuned to 22psi on a 190 with 560 pink tops.

 

[5150DSM]

General rule of thumb for piggybacks is to use the smallest injectors that will meet your horsepower goals. Read the links I posted earlier along with the upgrade path and you'll have a pretty good idea of what you need to get where.

Tech Guide - DSMtuners

 

[98_tsi_]

The reason for boost creep is the o2 housing. The stock dsm one is too small for the 16g. After you free up the exhaust the wastegate doesn't let enough exhaust out of the restricted hole so boost creeps then you hit fuel cut. Only way to fix it is to port your o2, buy a evo3 o2 housing or another type of aftermarket housing. That should fix the problem.

 

[caseclipsegst]

I do have a Megan o2 housing.. Do I need to port it?

Thanks for the info guys.. Ill have to save up for the wideband and logger.. Any temporary fixes y'all can recommend for now? And what is the best wideband to go with? I was looking at the digital aem wideband

 

[Stee420aT]

Wide band definitely makes a huge difference. A AFC would probably help too.

 

[Bud92gsx]

Op..Listen..I see a 255 rewired with stock injectors no afpr, no tuner system.Do you not see a problem there..Your doing it ass backwards.

 

[99ECLIPSEGSXDSM]

Your Megan o2 is good and if you want a quality wideband I would go with innovative. You have a 95 so I would go with Dsm link and totally forget afc and buy as big of injectors as you can afford cause there's no point in buying them twice.

 

[NHerron]

Jeez no solutions to this guys boost creep issue?

Yes a 3" high flow cat will have a high chance of fixing your issue. I had the exact setup as you but with the cat and held steady boost all day. Gutted the cat and bam boost creep city...

 

[R91TsiAWD]

What about the 34mm Wastegate flapper from FP and a ported wastegate? Think that would help at all?

 

[Bud92gsx]

Porting doesnt always help..Ask black widow..But if you tune for the creep, it can be ok..But you need a tuner asap..

 

[isantop]

Porting doesnt always help..Ask black widow..But if you tune for the creep, it can be ok..But you need a tuner asap..

I'm not super experienced with matters of turbos, but won't this make the creep worse? If you tune for it (I'm guessing by adding fuel to offset the extra air), then won't that make more exhaust and make the turbo spin faster?

 

[caseclipsegst]

I will be purchasing a ngr bov( read alot of good things about em )

A wideband and hi flow cat...I will get back with results after I install them..

I will save for some kind of tuning device afterwards!!

 

[NHerron]

The money involved to go external wg is not worth it on the 16g unless you are trying to max out the turbos flow and can't because the exhaust pressure is blowing open the stock wg flapper.

The issue is a lack of back pressure -post 02 housing. The nice big new o2housing flows a lot and way easier compared to stock and it flows even better hitting that 3". So this exhaust gas is nice, happy and not getting bunched up and slammed through a small opening anymore. It doesn't see any resistance to flowing once past the turbine so there's not much else this gas wants in life, its very content doing what its doing. So then the wg flapper opens and now what? How much exhaust is going to want to flow out this small new opening when they could take the big easy route.

Its like having a big garage door and a regular single door with 300 people waiting to come in. They're all going to take all enterances of course, but the percentage of people that went through the big door vs the smal door is way high.

 

[caseclipsegst]

Thanks nherron, what would be a good hi-flow cat to go with? I googled for a 3" one and one popped up but I believe it was a no name cat for $80