Impossible to get my boost target

[Mini Franki]

Hi,

I actually have a strange problem about my boost target and meth injection. Just for the info, my boost target are 16psi/3000rpm and 21psi/3500rpm(gtx2867r). Forget IAT compensation, i dont have it at this temperature. And, all my 2018 logs were done in the same day

Last year, all was good about my boost target and i had a stable boost on WOT(20.5-21psi). But this year, its impossible to get target and stability. The map is exactly the same. The difference with last year is a new pump(exact same pump) and a catless downpipe(i had a high flow cat)

Now, boost target are very worst. Its pretty hard to get my 21psi. I get my 1st 20psi at 4500rpm and after that still between 19.5-20.5psi(big variation). And i begin to peak over 21-22psi at +5800rpm. Its like ECU trying to compensate the WGDC for get the right boost target and that finish to peak too much at high rpm. So, i tried to climb up my WGDC of +10%. Result, no real difference

At the start, i was sure i had a leak or maybe the catless changed something. So i tried a leak test where my injection is, no leak. So i decided to try my old 20psi map without meth injection(i unpluged my meth controller. Nozzle and check valve still there). Strangly, all my target are good and boost are very stable(19.5-20psi). So, its not because a leak or the catless

Im out of idea, i really dont know what is the problem. I post here my log for help you to understand. There is clearly a problem

Thx for the help!


Wot 4 21psi meth 2017(high flow cat and 500cc): https://drive.google.com/open?id=1qa...o-kwSbVeGjFbA9
Wot 4 21psi meth 2018(catless and 500cc): https://drive.google.com/open?id=1FD...-VFZGwSNA_jY66
Wot 4 21psi meth 2018(catless, 500cc and +10% WGDC): https://drive.google.com/open?id=1To...KXEWsMJtPa1z8Q
Wot 4 20psi meth unpluged 2018(catless): https://drive.google.com/open?id=1tr...lsfx19dweivqja

[Mini Franki]

I put new link for read files directly on internet

[Mini Franki]

No idea?

[JSmith]

So...you removed a cat and didn't retune?

[Mini Franki]

My downpipe had a high flow cat, now im catless. That dont need a retune. That still, im hitting my target when i unplug my meth controller on my 20psi map

[Vansquish]

Actually, it probably does.

[kTaLgsTo]

Why reomove a high flow cat anyways? What did that gain you? 5 hp at best, or currently, just a bunch of problems...

[Mini Franki]

Tuner said that dont change anything to run catless. And i have 3port boost controller so its easy to.control the boost. I changed catless because its less expensive. Like i said 2 times, my boost target are good without injection. So its not because im catless

[Thor Hammer]

Sounds like you should be talking to your tuner.

Did you port the wastegate on your turbo? The Garret turbos are known to boost creep for some. Porting the wastegate hole solves the issue. Or going with an external wastegate. Might be worth looking into.

[Mini Franki]

I tried, but seem to be too busy for answer me

Anyway, that dont come from the map. Just need people here who know enough about tuning for read my log and see something i didnt. That will help me to find the problem.

I run gtx2867r since 100 000km and i never got problem about boost creep

Ill do another test later, ill try again to do a log with and without injection but now, with the same map. If the problem only appear again when im injecting, the hypothesis of catless or leakage is no longer valid

[Fstrnyou]

If hybrid tuned...might be hitting the load limits?

[Mini Franki]

Its boost based map, load limits are 3.0

After a test on my 20psi map with and without meth injection, logs are exactly the same. So its finally not the injection fault!

So catless seem to be the problem because all log describe that. It's probably not restrictive enough so it cant hit target in low/medium rpm and try to compensate and finally peak in high rpm. I dont search anymore, ill put back a cat high flow

[Mini Franki]

After added i high flow cat, problem still there. The only thing changed is, i peak less than before

So last hypothesis is, probably have a leak somewhere. I tried a leak test directly on the silicone tube of the intercooler to TB for see if my injection leaking. At 23psi, no leak from the nozzle

My question is, its normal the psi drop in 15-20 sec? Maybe a have a leak somewhere

thx

[Mini Franki]

That can be the corksport bpv, i heard some bad review about the wave spring broke. Ill check if it leak too

[Mini Franki]

Bpv is top shape, wave spring is good. All o-ring are good and greased. Boost leak test is good at 23psi. Im piss offff!!!!

Im totally out of idea

[JSmith]

So, you have placed the catted DP back in and now peak (boost pressure) less than before? Thats good.

If you connected at the throttle body (TB) then yes, you should expect pressure to drop, as you are flowing air through the engine. Try checking the TB silicone connection in the direction of the turbo outlet to check for piping leaks? Or get an air compressor w/ a pressure regulator and test at the turbo inlet through the entire intake track.

[Mini Franki]

I tested directly on my tb silicone for my nozzle, no leak(check valve removed and nozzle blocked). After i tested all the boost side(blocked the bypass hose), no leak. Yeah I lose maybe 1psi seconde when i test but i put air back in for maintain 23psi the most possible and i dont heard any leak

But the fact is, bpv is like a big hole leak no? If all the boost air go through it and go in the intake , how the motor can handle the boost? How a micro leak can change anything versus bpv

[Mini Franki]

For info, i have a upgraded tmic, so i dont have a lot of coupler. When i wot, i feel the unstable power caused by the big variation of the pressure(19-21psi)

[Fstrnyou]

You may need to adjust your boost correction table.

[Mini Franki]

Boost compensation are the same than all OTS map. But the problem dont come from the map...

[Fstrnyou]

Your wastegate actuator may be more sensitive to changes in wastegate duty cycle because drive pressures are different. Your boost correction table might now be considered too agressive if you see boost fluctuating trying to hunt the target.

BTW: OTS tunes are cookie cutter junk that are typically only good enough to get your car to run "okay".

[Fstrnyou]

Originally Posted by Mini Franki After i tested all the boost side(blocked the bypass hose), no leak. Yeah I lose maybe 1psi seconde when i test but i put air back in for maintain 23psi the most possible and i dont heard any leak

You lose (leak) 1psi per second and you think it's not a leak? GTFO! I don't believe it's a huge leak, but it's not helping anything.

[Mini Franki]

I already have 10% of wgdc compensation. Its a BT custom tune and my tuner didnt touch the boost correction table

I dont heard a audible leak if i have one but losing 1psi second seems normal according to the guys of the forum. Because pressure leave by the motor valves, this is not perfectly sealed

The think i dont understand is, all the pressure leave by the bpv hose is like a leak no? So why a little leak somewhere else can play on that?

Since i disassembled, cleaned and greased my bpv, i think that helped. I need to do a log again. Ill maybe buy a new oring kit for it just for be sure

[Fstrnyou]

The BPV isn't open when you're boosting, so no its not a leak...or at least it shouldn't be leaking.

Your valves should seal pretty good. I'd hate to think it's normal for combustion to blow past the valve into your intake...even if it's a miniscule amount.
During a cylinder leakdown test, ideal would be 100% of the leaking is going past your rings and nothing going past your valves.

[Mini Franki]

Ok i understand

I didnt do a leakdown test, only a boost test for check leak between turbo and motor. You suggest to me to do a leakdown test?

[Fstrnyou]

I only made a reference to leakdown test because that is the test to check for leaky valves, injector seals, or excessive piston ring leakage. If your valves are leaking, you've got other problems.
Now, during a boost leak test, you are applying pressure to the back side if the valve. Valve springs are only so strong and excessive pressure in the intake can push them open and leak. I believe that value for our stock springs is near 30psi, plus or minus a few.

[Mini Franki]

Ok ,ill do a last log for see if problem still there. If yes, ill do a check up at my speed garage

Another thing, when i did my boost leak test, that smelled a bit gaz, this is normal?

[Jeff23spl]

When i told him about the leak test pressure and internal drop, i was referring to 1out of 4 cylinders always have open valves so i would be surprise you can inflate turbo inlet side and not lose air inside the engine.

I mentionned the bov leak after he checked the 2 hose of the tmic setup...BTW ....The BPV valve should remain sealed closed under boost. (It should only open under vaccuum)
The o-ring on mine was shot and i had a leak from the top so the piston may not hold the boost correctly just by the spring...

So if you replace your filter by a boost tester and you don't get leaks outside of the engine...That point is good.

Running bt with all sort of mods, i don't think you can expect the tune to react like a clock with always the same exact level and response time you had the week before. Some days it is colder and boost rise faster, some warmer days make it harder for the engine to flow....All the parameters has a margin factor....

I did notice last month that if i ran out of meth, it takes about 10-15sec of pump running full speed to bleed air out of the system....The car will react differently under that condition.

Checking corrections tables could be a good place to confirm the tune allow enough error factor...

Checking the maf cal and fuel trim could be another way to find out if there is something wrong.

Mini-Franki may try to fine tune it with his tuner and probably would need to give a little more room to the error margin...

For the smell, it could be some oil mix from the piping but make sure you don't have a fuel leak around the hpfp/injectors if it really smell like a clean fuel spill...

[Fstrnyou]

Originally Posted by Jeff23spl When i told him about the leak test pressure and internal drop, i was referring to 1out of 4 cylinders always have open valves so i would be surprise you can inflate turbo inlet side and not lose air inside the engine.

I want to shoot myself now. I see now that the pressure drop he was seeing wasn't leaky valves, but air sneaking past the rings on the cylinders that had open intake valves.

[Mini Franki]

@fstr

I cant hate you, you tried to help me and i appreciate it

Car seem to running good since i do a bpv tune up. Grease the oring help to seal and to reduce chance to leak

New orings are coming. Ill give news soon

Thx for help

[Mini Franki]

Problem still there after new orings

[Mini Franki]

Solved, changed my 3 way boost solenoid fixed the problem. Very strange, the old one had 2 years...

[mituc]

Originally Posted by Mini Franki Solved, changed my 3 way boost solenoid fixed the problem. Very strange, the old one had 2 years...

What brand was it?

[Mini Franki]

That was the Cobb one. But cobb use MAC. I directly bought it from MAC, less expensive when you already have the plug and the fittings