1.8 BT stroker loss of power at 4400 rpm

[1975jcbg]

Hello everybody. I have been looking and learning with all of you for some years, developing my Seat Leon 1.8T from Spain. but now i have to get ehlp to all MASTERS of 1.8t because in my last evolution my car has a problem what I can't solve. First of all I put my mods (tranks to INA for all):
- Engine 1.8T AMK
- Stroker kit 2008 cc CR 9.5:1
- Ferrea springs valve
- Inconnel Exhaust valves
- Stock intake valves
- Stock hydraulic lifters
- South Bend Stage 2 clutch
- South Bend Lightweight flywheel
- Walbroo 255 intank fuel pump
- Fluidamp
- Forge Splitter Blow off
- Oil catch can
- Turbo BW 6758 internal WG
- RS4 MAF body
- FMIC
- Silicon hoses for all
- SEM intake manifold
- 80 mm TB
- Siemens 870 cc
- Ported and polish AMK head
- RS4 spark plugs
- TFSI coil pack
- 42 Draft Design 3" complete exhaut with Magnaflow Backbox
- N75 connected but not in use
- AEM tru boost
I am going to try to explain the problem. With a final electronic tuning with my chiptuner, the idle is good. But in the dyno, car is perfect from 900 rpm to 4400 rpm and then, the car loses a lot of power and torque, and then car doesn't recover power/torque well. It is like if something "brakes" the engine. We have make logs about throttle body, lambda, timing, maf, boost presure, intake temp... and all is OK. We have proob with diferent cams with the same result. The first run was with 0,9 bar, and we went up boost till 1,7 bar. But car allways loses power/torque at the same rpm.
We made a dyno with car without turbo, and car lose power/torque too at same rpm (lose fewer power). Always at 4400 rpm. We have change the cam tensioner too, but with the same result.
We have seen that when car goes to 4500 rpm, a lot of air/vapor goes out from the valve cover through the hose of the oil catch can.
I'll try to put here some dyno sheets.
Masters of 1.8t, what do you think that it is the problem? We are desesperate. I can make some logs if you need to help me.
Thanks for all

 

[csd_19]

Have you changed your fuel pump? I don't see it on the list above

 

[1975jcbg]

Yes. I edit the post. I have a Walbroo 255 intank fuel pump.
Thanks

 

[1975jcbg]

Here is a dyno at 0,9 bar


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[grahams81]

Hi, i have a couple of questions -

What exactly happens during this "loss of power" time @ 4400rpm - i.e

do you lose any boost pressure ? Fast loss of pressure / pressure stays the same ?

I think if the throttle body was closing (for some reason ??) then the pressure would rise quickly and maybe the BOV would open.

What software / mapping are you using ??? (the reason i ask is maybe the car is sensing an over boost situation then automatically backing it off / limp mode / timing pull for safety.)
Any error codes / messages from the ECU ?

Have you tried using only low boost for testing ?

Also your information about the excessive Breather pressure after 4500rpm seems strange.
Is the air in the breather system only coming from the valve block or also from the crankcase breather pipe ?
If the boost pressure is pressurising the breather system then there are only a couple of reasons for this -
Blow-By past piston rings (maybe engine is not run in yet ?? use mineral oil and not synthetic)
Cracked cylinder head - allowing compression to enter oil ways
Cylinder head gasket leaking or head lifting once boost pressure increases. (torque settings of head ok - ARP bolts etc used ?) Any oil in water / visa versa ?

Hope we can help you as your project sounds good

 

[1975jcbg]

Thanks Graham.
When power loss there is no fault codes. Boost presure manteins till red line. We have seen that air from breather is normal, seen a stock cupra.
We have tested with diferent boost because we don't have more ideas.
When power loss then, power doesn't rise quickly. Always like that dyno curve independent of boost, after 4400 rpm.
I use Motul 300 v 5-40. No oil in water. Compresion is about 10 bar in each cylinder. My electronic is made from the begining by my tuner.
I'll try to post some logs tomorrow.
Thanks again.

Enviado desde mi Androide

 

[1975jcbg]

If you want to see my project, please visit this link with all pictures:
https://www.facebook.com/media/set/?set=a.277627402277879.73163.275301752510444&type=3

 

[grahams81]

Nice project, you should write a build thread in the readers ride section, there will be a lot of people who will enjoy reading your progress

What software is your tuner using to control the mapping ?

 

[1975jcbg]

I'll do Graham. I am reading your project too.
I don't know what software is using my tuner. My car before this project, had a GT3076 and car ran very good (375 hp - 430 Nm - 1,4 bar) without stroker. I think the tuner makes the mapping from the beginning for each customer.

 

[1975jcbg]

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LOGS 0,6 BAR


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LOGS 0,9 BAR


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If you need more logs of different channels, tell me please.
Thanks all

 

[1975jcbg]

Graham, y reply you to this:

What exactly happens during this "loss of power" time @ 4400rpm - i.e

do you lose any boost pressure ? Fast loss of pressure / pressure stays the same ?

I think if the throttle body was closing (for some reason ??) then the pressure would rise quickly and maybe the BOV would open.

BOV can't open because I don`t have N249 and BOV pressure is connected directly to the intake manifold. Then if car goes to limp mode, turbo blows the same.


Also your information about the excessive Breather pressure after 4500rpm seems strange.
Now we are testing this to see if there are pressure or only air.

Is the air in the breather system only coming from the valve block or also from the crankcase breather pipe ?
Maybe from both. I have connected the pipe from oil filter support to valve cover breather, and with a "T", to the oil catch can.
If the boost pressure is pressurising the breather system then there are only a couple of reasons for this -
Blow-By past piston rings (maybe engine is not run in yet ?? use mineral oil and not synthetic)
Compresion tst goes to 10 kg in each cylinder
Cracked cylinder head - allowing compression to enter oil ways
Imposible. Only test car at 0,9 bar. And we have tested the head 2 times
Cylinder head gasket leaking or head lifting once boost pressure increases. (torque settings of head ok - ARP bolts etc used ?) Any oil in water / visa versa ?
No oil in water or vice versa. We use INA torque settings for all ARP bolts of all engine.

 

[underpressure]

i think the EFR Turbos comes with the low pressure Wastegate Canister. Do you try the medium or high boost canister?

 

[ibizacupra]

airflows for an rs4 sized maf look wrong to me
injector scaling looks off... pulling fueling to the tune of ~15% until boost comes in..

what actuator only pressure does it run, and if you alter the wastegate pressure for the higher canister, does the dip change also?

 

[1975jcbg]

i think the EFR Turbos comes with the low pressure Wastegate Canister. Do you try the medium or high boost canister?

Thanks. Sorry but I don't understand. EFR 6758 wastegate support no more than 0,9 bar. This is for what I have made all test at this boost. I use an AEM Tru Boost to control boost.

airflows for an rs4 sized maf look wrong to me
injector scaling looks off... pulling fueling to the tune of ~15% until boost comes in..

what actuator only pressure does it run, and if you alter the wastegate pressure for the higher canister, does the dip change also?

Thanks. What numbers do you think that would be good for RS4 sized maf? You said that are wrong because till boost comes in, fuel isn´t adjust, yes?
I have closed the wastegate to the maximum, and it opens at 0,9 bar like you can see in the logs.

 

[ibizacupra]

RS4 scaling..woudl relate to power which I cant see from logs alone.

the fueling is adjusting large % as you can see.

 

[1975jcbg]

Thank ibizacupra. What channel would we need t log, to see is RS4 maf scaling is correct?

 

[ibizacupra]

its in the map fella, not a log.
you are logging air mass flow on 002 and 003... but those numbers look low for your spec of car, even on 0.9bar, which to me looks like wrong scaling -

 

[1975jcbg]

Oh ok. I understand. Thanks

 

[grahams81]

Did you ever manage to fix the problems ?

 

[1975jcbg]

I am modifing the electronic and test.

Enviado desde mi Androide