[Mk2] [Turbo] Borg Warner EFR - boost drop at higher revs - end of ideas

[bobhatton]

I disconnected my wastegate actuator and the boost went up to 1.4 bar quite quickly.

That sounds like your boost control is not working very well.

Try a manual boost controller and see how your boost goes with that

[bobhatton]

Thank you very much for your explanation. Just got confused as my friend is using a 1.5mm headgasket and a stroker kit on his Skyline RB26DETT engine without any problems.

ATS is a good advice as I only had negative replies by now. But well, tomorrow is the first day after the 4-day bank holiday in Japan, so maybe I get a reply from JUN themselves. Will try ATS by tomorrow.


I also performed a compression test today. 11.5 bar on every cylinder, so good news regarding the piston rings and valve seats.

The boost lines from turbo to TB I also pressure tested up to two bar. No signs of a leak.

So more and more it goes in the direction of the squish area thing. Only bad part is, that I only found 1mm and 1.5mm solder, but nothing in between. Wanted to try a 1.2mm one. And if it is bigger than 1.5mm the next "buyable" size seems to be 2mm..... But I think, I can somehow solve that and buy some solder over the internet, if there is nothing else available in proximity. or maybe I use some 1.5mm and cut it a little bit so it is only 1.2mm, but this could be a quite dangerous attempt concerning my fingers


And just in case, I put my thinner genuine Toyota headgasket on... will I have to do a remap, or should the boost drop disappear without any remapping? I guess it should disappear, but the retarded ignition should be hard to change without being on a dyno, right?

Having too large a squish is far worse than having a too high compression ratio.
This is because if any charge is left in that area it is this charge that burns during detonation. When building a turbo engine this is one of the most important parts to get right.

If you want to get the most out of your engine the things to sort out are

1 Check the ECU control of the waste gate
2 Set the cams up correctly
3 Check squish and correct if wrong
4 Measure and calculate your compression ratio, is this correct for the fuel and boost being run.
5 Once all the above have been corrected map the ECU.

[bambam79]

I disconnected my wastegate actuator and the boost went up to 1.4 bar quite quickly.

That sounds like your boost control is not working very well.

Try a manual boost controller and see how your boost goes with that

Yep, that was no boost control working at all. I disconnected the wastegate actuator, so it got no pressure, at the wastegate was shut all the day. This is, why the boost went so high. It was mainly done by mistake, but so I could see, that the wastegate seat isn't cracked and the engine is powerful enough to produce enough boost.

Having too large a squish is far worse than having a too high compression ratio.
This is because if any charge is left in that area it is this charge that burns during detonation. When building a turbo engine this is one of the most important parts to get right.

Thank you very much for the detailed information. I think, now I fully understood why this area is so important.

If you want to get the most out of your engine the things to sort out are

1 Check the ECU control of the waste gate
2 Set the cams up correctly
3 Check squish and correct if wrong
4 Measure and calculate your compression ratio, is this correct for the fuel and boost being run.
5 Once all the above have been corrected map the ECU.

Ok, I will do so. This sounds like a good plan
Just having to seek some fitting solder. I will notice everybody here, when I measured the squish.
If I have to take the head of and change the headgasket to a thinner one, I will measure the compression ratio on that occasion.

[bambam79]

Well... had quite some research and thanks to NoddE I found the center lobe of my cams:
intake 110°
exhaust 115°

I will try to see, how much my cams are out of this and let you know

[bambam79]

Sorry for the monologue but while looking at my logfiles...

is that oil pressure ok? It is 10W60 and has reached about 80°C
but only 2 bar on idle and 3.7 bar on full throttle.... is that ok?

On the other hand, the fuel pressure of nearly 5bar seems a bit high at idle?


I have the A1000 fuel pressure regulator which should rise 1:1 with boost
http://aeromotiveinc.com/products-page/ ... -6-return/

[jimGTS]

My stock engine see's over 6bar oil pessure top end.
Taken from the holes near the gen3 oil filter housing.
I see 2bar at idle at like 90c (750rpm)

Fuel pressure at idle should be 35-38psi ish. So 2.5bar ish.

[ashley]

Fuel pressures does seem a bit high, try dialling it down to ~3bar at idle.

I'll have to go back to my own data logs, but from memory I was seeing ~5bar cold oil pressure at idle, this would obviously drop once warmed up

[Marf]

Fuel pressures does seem a bit high, try dialling it down to ~3bar at idle.

Careful.. if he does that his map will lean out surely?

[ashley]

Fuel pressures does seem a bit high, try dialling it down to ~3bar at idle.

Careful.. if he does that his map will lean out surely?

Good point, would need to be done as part of a remap

[bambam79]

Oil pressure might be within the acceptable values, even if at the lower edge. I measure it at the top of the head, where the oil pressure genuinely is measured, too. With warm oil and only 2 bar at idle it is not uber-brilliant, but maybe acceptable.

Which makes me think is the fuel pressure. I have the SX pressure regulator sold by wolfkatz

This should rise 1:1 with boost, right. So why do I see nearly 5bar at idle? And less on full boost?
I precisely set the fuel pressure to 3bar when building the engine.... so reading nearly 5 bar quite hit me, when I noticed that yesterday evening.
But if there is something mixed up, the engine shouldn't run at all, or at least absolutely awfull, right?
Maybe when set up via lambda the engine may run relatively smooth, but under full throttle there should occur some issues?

[ashley]

Check that the adjustment nut on the FPR hasn't worked loose

[bambam79]

Check that the adjustment nut on the FPR hasn't worked loose

Yep, wll do so. Checked my older logfiles. There was everything working right. So this is a problem, but a new one.
Here you can see that everything was spot on (despite the quite low oil pressure ) some time ago:


But if the nut had worked loose, then the pressure should have lowered, shouldn't it? Anyway, I will check it. But as I have a 5bar sensor, I fear, this could have been destroyed when the pressure went higher than the 5 bar on "full" boost. But the nut is probably more easy to check, so I will do this first

Ok, nut is still in place and doesn't move. So something else. That engine starts getting on my nerves. Not even solved the first problem and it comes up with another one

[bambam79]

Well, that squish testing was some fun. And I still don't know, if I got the solder straight till the end, as the biggest solder I had was 1.5mm and it wasn't touched by the piston and head, so not squished.
So either I have more then 1.5 mm squish, which is within possibility, or I didn't push it far enough in, which might also be possible.
This solder is so flexible and the fact that the sparkplug hole is so far down and tiny makes the whole action a nice test to find out if someone is patient or not. After about one hour I gave up further testing and decided that my squish is beyond 1.5mm and that this might be the possible cause.
So together with dialling in my cams properly I will change my headgasket for a genuine Toyota 1.0mm one.

Last test tomorrow should be the mentioned pressure using to operate the wastegate actuator. I will try taking the pressure from the air intake to avoid the backpressure built up from the chargecooler.

Thank you everybody for supporting me

[bambam79]

everything is fine so the only bad thing was taking the wastegate actuator operating pressure from the compressor instead of from the intake manifold.

Bow with the higher spring rate actuator, the car boosts 1.5bar well beyond 6000rpm. Unfortunately at 61xxrpm my fuelpressure dropped too much and my car went into limp mode.

So this is the next problem to solve

[bobhatton]

everything is fine so the only bad thing was taking the wastegate actuator operating pressure from the compressor instead of from the intake manifold.

Bow with the higher spring rate actuator, the car boosts 1.5bar well beyond 6000rpm. Unfortunately at 61xxrpm my fuelpressure dropped too much and my car went into limp mode.

So this is the next problem to solve

It sounds like your pipe work and intercooler has a high pressure drop.

What is your fuel system, pump, filter, hose types and size etc.

[bambam79]

[quote="bobhattonIt sounds like your pipe work and intercooler has a high pressure drop.

What is your fuel system, pump, filter, hose types and size etc.[/quote]

Yes, it sounds like that. Should be something like 0.3 bar according to the boost drop. I am trying to source a free sensor Input on my ecu to get an accurate boost reading before and after the intercooler.

This is my fuel line and pressure Regulator system: http://www.wolfkatz.com/proddetail.php?prod=EEWKFKALLSS

and here's my fuel line: top feed with the former 870 Delphi injectors
http://www.wolfkatz.com/proddetail.php?prod=AWKMR2TFFR

fuel pump is a genuine supra one

The lines from the pump to the filter (only the standard Toyota one) and the return lines are the stock ones

[2mad]

On the other hand, the fuel pressure of nearly 5bar seems a bit high at idle?


Must admit I only skimmed through 5bar idles crazy (full boost could be knocking on 7bar anywhere between 2 to 3 bars were you should be at depending on mapper .. I tuned mine and i was no where near that high ... best of luck mate


Yes this..

Check that the adjustment nut on the FPR hasn't worked loose

[bambam79]

On the other hand, the fuel pressure of nearly 5bar seems a bit high at idle?


Must admit I only skimmed through 5bar idles crazy (full boost could be knocking on 7bar anywhere between 2 to 3 bars were you should be at depending on mapper .. I tuned mine and i was no where near that high ... best of luck mate


Yes this..

Check that the adjustment nut on the FPR hasn't worked loose

Thanks. This issue is solved. The return line was kinked. Now it is fine. Idle fuel pressure is 3.1-3.2bar

[2mad]

On the other hand, the fuel pressure of nearly 5bar seems a bit high at idle?


Must admit I only skimmed through 5bar idles crazy (full boost could be knocking on 7bar anywhere between 2 to 3 bars were you should be at depending on mapper .. I tuned mine and i was no where near that high ... best of luck mate


Yes this..

Thanks. This issue is solved. The return line was kinked. Now it is fine. Idle fuel pressure is 3.1-3.2bar

Good stuff glad its sorted