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

[bambam79]

I think your hotside is too small personally..

Then he'd see EGT's climbing rapidly as boost was increased wouldn't he?

Not sure, if boost cannot rise as the turbine can't spin any faster due to the hotside being too small then would EGT rise?

the exhaust gasses can't escape fast enough through the turbine and stay longer in the exhaust manifold. Therefore the EGT usually rises.
But as I only did a quick pull in third to redline and not drove 2 minutes at 6000+rpm I am not sure, if this is representative.


Anybody else voting for the cams?
The thing that bothers me is, that everything is fine under 0.8 bar... and that the car has no ditch in the torque graph. I thought this would exclude the cams. Because, if they are wrongly dialled in, then the idle would be terrible and revving might be nearly impossible?

And why is there a mark on the cams, that tells, like the stock mark where the cam should be mounted?

As far as I know are JUN camshafts machined from new and not reground ones.



next wild guess is the fuelling... but fuel pressure rises from 3.5bar to 4.5 bar when under load and acts simultaneously to the boost curve. So I don't suspect a problem here as well

[bobhatton]

You do need to get the cam specs and set them up first.

Your timing is very retarded. The stock engine under boost is up around 30-35 deg

Is your timing + the stock 10 deg static, or is total?

To run so retarded you must have high cylinder temperatures and or pressures. If it is because of knock it may be you have this because your piston to head clearance is too large.

0.64 AR is the main size used on a road going engine and should not be your main problem

We will get to the bottom of this, may just take a bit of time.

[bambam79]

You do need to get the cam specs and set them up first.

I have contacted JUN to kindly send me a new spec sheet for my cams, as I don't have it Nevertheless I am wondering why they put a spot on the cams.

Your timing is very retarded. The stock engine under boost is up around 30-35 deg

Is your timing + the stock 10 deg static, or is total?

To run so retarded you must have high cylinder temperatures and or pressures. If it is because of knock it may be you have this because your piston to head clearance is too large.

Well, I think this was the ignition map for the 95ron fuel. But the 98RON fuel isn't much different. 16.56°BTDC at 6800rpm 0.9 bar
Unfortunately I don't know if it is the timing is total or + stock 10° static. I will have to ask Ryan G to tell me as he mapped the car.

Can I somehow check the piston to head clearance with the head on? I guess not

0.64 AR is the main size used on a road going engine and should not be your main problem

ok, so turbo is out of the way

We will get to the bottom of this, may just take a bit of time.

Your confidence is very good to hear. Thank you very much!!!

[ashley]

What injectors do you have, and what's the peak duty cycle looking like?

What size fuel lines?

Dead head or through rail set up?

[ashley]

Well, I think this was the ignition map for the 95ron fuel. But the 98RON fuel isn't much different. 16.56°BTDC at 6800rpm 0.9 bar
Unfortunately I don't know if it is the timing is total or + stock 10° static. I will have to ask Ryan G to tell me as he mapped the car.

Given that you are running COPs I'd guess it's total timing, static timing is only relevant for a dizzy isn't it?

[bambam79]

What injectors do you have, and what's the peak duty cycle looking like?

What size fuel lines?

Dead head or through rail set up?

I have the wolf-katz topfeed fuel rail including their 870cc/min Delphi injectors. Seems they now switched to Bosch and Lucas injectors, but mine are the Delphi ones.

Fuel lines are AN6 if I am remembering right, I can take a look later, but I think this doesn't matter, as my line to the fuel filter is still stock and the fuel filter is also stock, so the most restrictive parts should be the stock fuel lines... if they are a problem.

duty cycle when coming to 1.2 bar looks fine to me:

[ashley]

Yep- looks good, just eliminating possibilities...

[2mad]

It looks like 0.64 AR is to restrictive for your setup.

Just my thoughts, not an expert or anything

[ashley]

If it was too small a turbine housing then you'd be seeing huge backpressure as boost is ramped up, and EGTs climbing to the sky (1000c+)...plus you'd probably see more boost as well, just the turbo having to work harder and harder to make it and things getting hotter and hotter.

There's something else happening here

I reckon you need to dial your cams in...

[bambam79]

Yep- looks good, just eliminating possibilities...

Yes, and thank you very much for that. Always welcome.

A faulty wastegate was what I had in mind some time ago, too. Maybe a crack in the seat. The wastegate itself operates fine and is completely free. Can close and open when putting pressure onto the actuator.

But I had now idea how I can test a cracked wastegateseat

while under ECU operated boost control it showed a 100% dutycycle for the wastegate but the boost still dropped. I tested three wastegate actuators. Two medium bosst ones and one high boost actuator, which is on at the moment. So I doubt, that it is the actuator. It has to be the wastegate itself, but as I said, no idea how to test it as it is internal If I put pressure in the inlet of the turbine and close the wastegate to test, every air would escape over the turbine...


I hope JUN gets in touch with me regarding the camshafts, but as far as I could see on there homepage, there might be bank holiday tomorrow and Friday.

And this head clearance thing with the retarded ignition has gotten my interest as well. Never heared of it before and will have to do some research. I have to discover, if my headgasket might be too thick.

Or if Ashley points me at the right thing first

[ashley]

Trying to find some gen on setting up the JUN camshafts, do you have the part numbers your ordered?

[bobhatton]

And this head clearance thing with the retarded ignition has gotten my interest as well. Never heared of it before and will have to do some research. I have to discover, if my headgasket might be too thick.

Or if Ashley points me at the right thing first

http://en.wikipedia.org/wiki/Squish_%28piston_engine%29


And this one

http://www.sacoriver.net/~red/squish.html

[ashley]

That solder idea is a good one

[bambam79]

Trying to find some gen on setting up the JUN camshafts, do you have the part numbers your ordered?

Intake cam: 1004M-T002
Exhaust cam: 1004M-T102


and now off to read bob's links. Thank you very much everybody. It helps a lot and I feel so much better after today

edit: back and definitely buying some solder tomorrow

and something that came to my mind concerning the wastegate:
I disconnected my wastegate actuator and the boost went up to 1.4 bar quite quickly.

My oil temp sensor line was broken at this point so the ecu limited the engine at 4000rpm
But I guess with a slightly blowing wastegate the boost wouldn't have climbed so quickly and so high, right?

[ashley]

Jeez- really not much info easily available for those cams is there!

Did they come back to you yet?

[bambam79]

Nope. I guess there is bank holiday in Japan, as today and tomorrow were marked red like the weekend days.

I think I will try and contact several companies that sell these camshafts as well. Maybe there is one, that sells me the specification sheet separately

[ashley]

You could try some of the specialists on here- someone must have used JUN cams before, maybe even try contacting Fensport?

[bambam79]

Yes, maybe I try and post a new thread where looking for info from someone used them here.
Fensport unfortunately doesn't sell these cams and I got one reply so far, from nengun telling me that they don't have any paperwork weird, as they sell them. I told them, that I am willing to pay for the cam sheet, but still a no


And I had a thought about that squish area thing: When putting in a stroker kit, then the con rods are shorter, right? Therefore the cylinder-deck distance must be much more than 1mm. How comes that this is not a problem then? Or am making a mistake on this?

[ashley]

Yes, maybe I try and post a new thread where looking for info from someone used them here.
Fensport unfortunately doesn't sell these cams and I got one reply so far, from nengun telling me that they don't have any paperwork weird, as they sell them. I told them, that I am willing to pay for the cam sheet, but still a no


And I had a thought about that squish area thing: When putting in a stroker kit, then the con rods are shorter, right? Therefore the cylinder-deck distance must be much more than 1mm. How comes that this is not a problem then? Or am making a mistake on this?

You've confused yourself! On a 2.2 crank the big end journals are further offset from the centre line of the crank, so at TDC the big end journals are closer to the block deck than with a 2.0l crank.

So when you build a stroked block you typically use the 3S (2.0l) rods, but use pistons with the wrist pins closer to the piston crown. This means at TDC you have absorbed the increase in height from the offset big end journals, and the piston crowns are at the same height as on the stock motor (and squish area remains the same).

Try asking ATS in America- they're pretty expert at these engines and may have some data on your camshafts

http://www.atsracing.net/

[bambam79]

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?