Help Me Eliminate My Boost Spike/Creep

[Cgillies86]

Ok, I just bought this dsm; and it has massive boost creep. I don't know much about hese cars so I need help with eliminating the boost creep. If i floor the car the boost goes to 8 psi. Then at 4k it shoots to 15psi, at 5k the boost reaches 22 psi, and at 6k it skyrockets 30 psi. I pretty much stopped flooring the car because it boosts so high. I am not really sure what is causing the boost spike so any help would be appreaciated.

My Cars Mods:
Full 3 inch Exhaust Downpipe and back, Test Pipe, Hybrid Connection O2 Housing 2.5 inch, 2g Exhaust manifold, 14b Turbo, Dejon Tool 2.5 upper and 2.5 lower intercooler pipes, 3 inch air intake pipe, 7 inch K&N air filter, SBR boost controller, MAFT, GM MAF Blow-Thru, Walbro 255 fp, Aeromotive FPR, 450s, S-AFC II, pocket logger, EGR block-off and All other Emissions

Temperature was 30 degrees F.

Let me know if you have any ideas on how to reduce this boost creep.

 

[Cgillies86]

Here are the pictures of the wastegate, I still have to smooth it out; let me know what you guys think.

 

[oldman]

Honestly, looks like you did a minimum job. Read throught vfaq and look at what they did and compare it to what you did. I would use this opportunity to do a complete port job:

1. Enlarge the entire inlet not just the wastegate area, knock off more material on top of the wastegate path, grind out all rough edges and polish it.

2. You did manage to open the door all the way but you stoped short. Follow vafq on porting the wategate outlet, match the o2 housing side and grind down the gasket to match them.

the only thing vfaq didn't cover was the inlet part so if folow everything on vfaq and port the inlet just like the pic I provided above, not only you should cure the creep, you've also improved the spool up time. You're almost there, do it right and do it once.

 

[Cgillies86]

Honestly, looks like you did a minimum job. Read throught vfaq and look at what they did and compare it to what you did. I would use this opportunity to do a complete port job:

1. Enlarge the entire inlet not just the wastegate area, knock off more material on top of the wastegate path, grind out all rough edges and polish it.

2. You did manage to open the door all the way but you stoped short. Follow vafq on porting the wategate outlet, match the o2 housing side and grind down the gasket to match them.

the only thing vfaq didn't cover was the inlet part so if folow everything on vfaq and port the inlet just like the pic I provided above, not only you should cure the creep, you've also improved the spool up time. You're almost there, do it right and do it once.

What should I use to grind out the rest of the inlet?

 

[oldman]

What should I use to grind out the rest of the inlet?

I used die grinder/carbide double cut burrs and then smothed it out using diamond burrs/dremel, sand it down using 80, 120, 200, and finished it off with 320 git sand paper. You can skip first step if you don't have the tools but it will take longer using just the dremel. Take your time with it, the results will be worth your while. Have you read throught vfaq/porting yet?

 

[Cgillies86]

I used die grinder/carbide double cut burrs and then smothed it out using diamond burrs/dremel, sand it down using 80, 120, 200, and finished it off with 320 git sand paper. You can skip first step if you don't have the tools but it will take longer using just the dremel. Take your time with it, the results will be worth your while. Have you read throught vfaq/porting yet?

Yea, I read the vfaq on it. I only have a dremel so, I guess it will take a long time to get all that out of the inlet.

 

[Cgillies86]

Here is an update on my exhaust housing. It is coming along, I am going to grind it some more, so I get as much flow as possible from a 6 Cm gasket. Then I will sand it and I will be done! I am pretty sure this will fix my boost creep.

 

[oldman]

Here is an update on my exhaust housing. It is coming along, I am going to grind it some more, so I get as much flow as possible from a 6 Cm gasket. Then I will sand it and I will be done! I am pretty sure this will fix my boost creep.

That took you almost 2 weeks? Make sure the dremel was pluged in.

I must say you did a very good job on that. However, I'm going to see how far I can push you on this. Instead of doing a 3/4 job, why not get yourself a 7cm gasket and match the inlet to it. Get rid of that step like shown in vfaq. Now here comes the harder part, I don't what exhuast manifold you have but if you have the stock 1g, I would invest in a used 2g and port the collector to match the 7cm gasket. If you already have the 2g, unbolt it and port. I know it sounds like a lot more work but this is one of the best free mods around. Also make sure you don't put that metal ring gasket back in.

 

[Cgillies86]

That took you almost 2 weeks? Make sure the dremel was pluged in.

I must say you did a very good job on that. However, I'm going to see how far I can push you on this. Instead of doing a 3/4 job, why not get yourself a 7cm gasket and match the inlet to it. Get rid of that step like shown in vfaq. Now here comes the harder part, I don't what exhuast manifold you have but if you have the stock 1g, I would invest in a used 2g and port the collector to match the 7cm gasket. If you already have the 2g, unbolt it and port. I know it sounds like a lot more work but this is one of the best free mods around. Also make sure you don't put that metal ring gasket back in.

It took two weeks because i was just to busy with school. It actually only took an hour or so to improve on my previous attempt. I have a 2g manifold, it's not ported, however i would like to port it eventually. I don't think I wil just yet, I just really want to drive my car without hitting boost creep. I still have not been able to floor my car since I bought it. I will probably put that exhaust housing on this weekend; I'll let you know what happens.

-Chris

 

[rowlex]

Hey...after following this thread for a while and my car creeping to...well whatever it wants to I pulled the mani off and ported the path to the wastegate.

I opted not to port any material other then the path to the wastegate...and the step. I removed the step on the manifold collector area, but no more. As that is going to be a BEASt to port. Tons of material to remove. I did about the same job on the path as you have, i left the turbo in the car, so i did not hit the wastegate hole at all. I can now hold 1.38 bar, which is quite close to 20psi until redline. It does have some slight hickups tho (around 15 psi i get an awkward loss of power/jerk) my boost seems to be ill erratic at times also.

 

[oldman]

It does have some slight hickups tho (around 15 psi i get an awkward loss of power/jerk) my boost seems to be ill erratic at times also.

Check the plugs and wires then do a boost leak test before you jump into any conclusions.

 

[rowlex]

Check the plugs and wires then do a boost leak test before you jump into any conclusions.

Thanks for the tip oldman. I think the plugs are actually a few thousand miles old, and If i remember right i gapped them at .031-.032 when I was running much lower boost. I know my plug wires are old, I'll have to replace em.

 

[johnk]

Don't know if all your porting work has fixed your boost creep issues yet. If not you can check your boost controller. If it was installed backwards or the adjuster backed out you get uncontrollable boost.

 

[Cgillies86]

Here it is, I finished my port job. I decided just to go with the 6cm becuase I just really want to drive my car. I will upgrade my turbo later anyways so this is basically a bandaid til then. I think it turned out quite nicely for my first port job. I am putting it on tommorrow after i get back from my classes, I just hope it fixes my boost creep. Let me know what you think.

 

[25psi]

Don't know if all your porting work has fixed your boost creep issues yet. If not you can check your boost controller. If it was installed backwards or the adjuster backed out you get uncontrollable boost.

Yeah I'm thinking it's not WG flow related if he is creeping to 30psi. Just make sure the actuator arm and the flapper are ok.

 

[Cgillies86]

Yeah I'm thinking it's not WG flow related if he is creeping to 30psi. Just to make sure the acuator arm and the flapper are ok.

I actually tested the wastegate actuator yesterday. And it fully extends at about 11-12 psi of air. Full extension is roughly a 1/2 inch. So i believe it is working.

 

[oldman]

Here it is, I finished my port job. I decided just to go with the 6cm becuase I just really want to drive my car. I will upgrade my turbo later anyways so this is basically a bandaid til then. I think it turned out quite nicely for my first port job. I am putting it on tommorrow after i get back from my classes, I just hope it fixes my boost creep. Let me know what you think.

Very nice.

 

[25psi]

I actually tested the wastegate actuator yesterday. And it fully extends at about 11-12 psi of air. Full extension is roughly a 1/2 inch. So i believe it is working.

Wierd, I've never heard of creep being that bad before. Good luck with it, your o2 housing looks like it will flow big time now .

 

[oldman]

Thanks for the tip oldman. I think the plugs are actually a few thousand miles old, and If i remember right i gapped them at .031-.032 when I was running much lower boost. I know my plug wires are old, I'll have to replace em.

You're welcome. You mentioned it now holds 20 psi to redline, Is your boost set at 20 psi? How bad were you creeping before?

 

[Cgillies86]

Very nice.

Thanks oldman for all the information you gave me throughout this thread; The info was invaluable.

 

[oldman]

Thanks oldman for all the information you gave me throughout this thread; The info was invaluable.

Glade to help. Just keep in mind that the car is still new to you so don't freak out if other issues pops up after this, like boost leak and such. After you get rid of the boost creep (knock on wood) other problem, if any, will become more apparent.

Get back to us with good news.

 

[rowlex]

You're welcome. You mentioned it now holds 20 psi to redline, Is your boost set at 20 psi? How bad were you creeping before?

well there seems to be some really bad jerking stuttering/etc with my car everytime i go into boost around 15 psi, and it scares me so i let off the throttle. ive seen my avcr's peak hold around 1.5 bar. at the time it held at 1.38-1.4 bar i had the avcr set to .90 bar ive now set it at 1.3 bar and it creeps to 1.38-1.4 bar.

im having even more problems with it now that i aquired a maf-t in draw through setup until i get the couplers i need to go blow thru. I just can't figure out the settings... here's a dsmlink log if you wanted to see what im dealing with . this is with the maf-t's last 3 POTS at -20%... http://www.posdsm.com/uploads/fuct.jpg

Also, I'd like to thank you as well for all the effort and advice you have put into this thread!

 

[oldman]

hehe I don't know how to read it yet. I will be installing my logger this weekend, give me a week to learn it and I'll try and help you there. I suspect that you're still creeping because you didn't port the area behind the wastegate to allow the door to open more so it's parallel to the flow to decrease the cross section. I would give that a shot when next opportunity arrives to see if you can cure it for good. As for the stuttering issue, I still will check the plugs and wires first. Since it's boost pressure related as well, a thorough boost leak test would be a great idea. If all else fails, try borrowing a known working mbc and mount it near the turbo to see of the ebc is troubling you.

 

[Cgillies86]

Even after all that porting I did, my turbo still boosts to 30 psi. But now with the turbine housing ported, it goes there insanely fast, almost instant. THe good news is, when I remove the wastegate arm from the flapper door, i dont make any boost until 5k and make less than .8 bars at the rev limiter. Before the porting, it would boost 30 psi even with the actuator arm off. I am wondering if I should just make my actuator arm longer. Let me know with any ideas.

Thanks

 

[rowlex]

hehe I don't know how to read it yet. I will be installing my logger this weekend, give me a week to learn it and I'll try and help you there. I suspect that you're still creeping because you didn't port the area behind the wastegate to allow the door to open more so it's parallel to the flow to decrease the cross section. I would give that a shot when next opportunity arrives to see if you can cure it for good. As for the stuttering issue, I still will check the plugs and wires first. Since it's boost pressure related as well, a thorough boost leak test would be a great idea. If all else fails, try borrowing a known working mbc and mount it near the turbo to see of the ebc is troubling you.

Ahh cool well the erraticness of the log shows how much the thing is jerking and stuttering, it should all be smooth. On that particular log my avc-r maxed out at 1.29 bar. It also shows 1.02 volts on my o2 sensor, So its running quite rich as well. I have to figure out the maf-t setup.

Strange everyone tells me to boost leak check, ofcoarse I dont think I have much of a boost leak since about 2-3 weeks ago I installed a FMIC with new piping, and brand new couplers. I do not have my pipes beaded as of yet, but I've checked all the clamps and couplers (tightened all the couplers down more as well) I've yet to blow one off but I've only done 1-2 good pulls on the setup. I do have the standard TB shaft leak tho (from the last leak test but was before my FMIC install). I need to make or borrow the pressure tool from my buddy

Thanks for your help and sorry for jacking this guys thread!
p.s. oldman, I have a 38mm tial external gate I'll be installing pretty soon I was just hoping to get it running decently on the setup I currently have.

 

[rowlex]

Even after all that porting I did, my turbo still boosts to 30 psi. But now with the turbine housing ported, it goes there insanely fast, almost instant. THe good news is, when I remove the wastegate arm from the flapper door, i dont make any boost until 5k and make less than .8 bars at the rev limiter. Before the porting, it would boost 30 psi even with the actuator arm off. I am wondering if I should just make my actuator arm longer. Let me know with any ideas.

Thanks

That sucks. Sorry to hear it, you ported the wastegate hole to didn't you??
I was told by an experienced friend of mine not to port the turbo inlet, JUST the path to the wastegate, as porting the whole thing decreases spool up time, and makes more room to allow the exhaust gases to enter the turbine wheel which is what we don't want. Are you running a stock(but ported) o2 housing? Sounds like your's and mine next best hope is an external gate... I have a cheap tubular manifold from punishmentracing.com that has a dump tube on it, and hope to be able to cut off the dump tube an inch or less from the flange and weld an external gate flange to it....

I have read some good info on messing with the actuator arm, look for pikens (his username on tuners) "easy cure for boost creep" or something to that matter. The guy never offered up and dimensions or anything on how to make the piece, but it simply raises the actuators arm (at the flapper area) a little higher making it possible for the wastegate to open further.

ALSO: I have heard that on some wastegates you can simply screw the wastegate arm, in or out to raise or lower boost; anyone know if this is true with the evoIII 16g?