86 505 Turbo Track Build

[Bean]

Does the timing stay static (8 degrees) when engine is revved?  Have you done the TPS adjustment and is it still in spec?  Cylinder compression on all 4?  Does boost build slow or quick? And what psi is it hitting?

Rabin

[Jayden M]

5 hours ago, V-M said:

Fuel pump? Have you lamda to read afr? Stock turbo?

Fuel pump is a new oem one. Fuel pressure is smooth and steady and within spec at any load range and rpm.
The turbocharger is a stock one, but its a big watercooled one from an N9TEA engine, .42 AR I believe.
I have not done lambda readings, but the O2 sensor is in and should be functioning as normal. I'd check it but im not sure what numbers mean what in terms of voltage readings.

 

 

1 hour ago, Bean said:

Does the timing stay static (8 degrees) when engine is revved?  Have you done the TPS adjustment and is it still in spec?  Cylinder compression on all 4?  Does boost build slow or quick? And what psi is it hitting?

These are all the things I thought and checked too and so far all i'v checked seems normal... mostly... TPS is adjusted in spec like it should and hasn't changed over the past few months so that's fine. Boost seems to build rather quickly, 5th gear 2000 rpm and not even 2 seconds later its holding a steady 13 psi by 2500 rpm. Boost is steady all the way up to the limiter too. I have yet to do a cylinder compression test, mostly because every kit I find does not have the bits small enough for these tiny ass spark plugs lol.

Now about the timing. This is the most interesting part. I have the ignition timing set to 20 degrees of advance. Now I know your probably thinking what in the hell, but it doesn't seem to be knocking. Originally I had this thing set to 12 degrees (which is within spec), but after setting it to 20 I have gained more power everywhere and seemingly with no drawbacks. Heck I used to have it set to 25 degrees but my dad said he may have heard a little knock at 25 so I brought it back down to 20. Also about the timing staying static... the timing advanced 10 or 15 higher than base timing if I rev it up to around 1800 so that seems to be doing fairly normal. Honestly this thing is just so weird it TOTALLY should not be able to run 20-25 degrees of timing advancement.

[Bean]

These cars HATE advanced spark.  I used to bump spark as well, but it ran SO much better at stock advance (8 degrees), with the tps adjusted.  Advancing the timing so much will/should effect idle. So if you’re running 20 advance and have proper idle (900 rpm?) it’s way off ideal.

I’d recommend setting timing to stock (like exactly), adjust idle, and recheck TPS readings, then retry.

FWIW - Bumping timing is an old school trick on cars without ECU’s - I used to race mine a lot (rallycross and autocross) and it ran best with stock setting and the TPS NAILED for adjustment.

Definitely wouldn’t be messing with big timing (or boost increases) unless you had EGT and WBO2 monitoring things.

Rabin

[Bean]

I wonder if the Cam is a tooth off - that would skew everything as well - one tooth retarded would likely give you the symptoms you’re experiencing power wise, and advancing the cam just lessen’s the effect…

Rabin

[Jayden M]

2 hours ago, Bean said:

I’d recommend setting timing to stock (like exactly), adjust idle, and recheck TPS readings, then retry

I'v tried doing this, as in timing set to stock, idle at 900-950 and TPS set right, but the car is a good bit slower this way so that's why for now its at 20. Putting the timing at 20 degrees does require me screwing in the idle screw fully otherwise I have like a 1500 rpm idle .

Believe me its scary having the timing at 20 degrees at first but it runs so much better like this. I don't want to push this thing that hard but I don't think I am. It's not like this thing is down 20hp it's down 80 or 100. If blackie has 180 hp then this thing might have 160. I think something thats telling is that the power band is so wrong. It encourages shifting a little before 6000 because the power drops off pretty hard around 5800.

 

2 hours ago, Bean said:

I wonder if the Cam is a tooth off

Its interesting you say that. I don't know how off this is but with the cam pulley tdc notch lined up with the mark on the head - that puts the crank pulley at 4 to 5 degrees of retard. Problem was if I used the next tooth on the timing chain it would make it be at like 10 degrees of advance so 4 degrees is as close as I could get it unless I was missing something.

[Bean]

Is that with the tensioner functioning?  Was the head milled at all?

Retarding the cam would do exactly what you’re experiencing, I just can’t say how much it would affect it. (Starts and idles well, moves power band down in rpm, runs out of poop higher in rpm.)

On my car with 12 psi and timing set to 12 degrees it would buck violently on boost.  Timing back to stock and ran perfectly.  I would never be able to run that much timing.

You could try moving one tooth ahead on the crank into the mix to see if a combo of crank/cam teeth moves gets you closer.  Failing that - could see about slotting the cam gear mounts to that it’s adjustable.

Definitely seems like cam timing could be your issue…  Have you done compression test?  Valves adjusted?

Rabin

[Jayden M]

I considered slotting the cam gear holes to adjust it properly but I was skeptical about it sliding around while running, just thought it was sketchy since I have never done something like that before. Valves are adjusted in spec. Compression test is not something I have done, hard to find a gauge to go in such a tiny spark plug hole, but ill do it eventually.

Im super allergic to all this pollen so unfortunately motivation to go outside is very low. I start sneezing and eyes are so watery. Ick

[Bean]

Same spark plugs as a sport bike so that should help find an adapter.  Cbr600f3 used the same 10mm plugs I believe.

Keebs slotted his cam gear and said it was fine, there’s a friction disk that would help if you can get the right size:  https://wctperformance.ca/ie-ekagrip-vw-audi-4-cylinder-cam-gear-friction-disk/

Would also use Nord-lock washers on the bolts to be extra sure.  https://www.nord-lock.com/en-us/nord-lock/products/washers/

Rabin

[V-M]

I made adapter from old plug, pipe and air connector. I would check timing and distributor gear play. Also distributor internals. Look with timing lamp if there inconstancy in spark and advance from idle to 4000-5000 area.  I made one gear with slotting but it did not make realy difference with dani cam.

[Jayden M]

4 hours ago, V-M said:

Look with timing lamp if there inconstancy in spark and advance from idle to 4000-5000 area.

If I have my base timing at say 10 degrees at idle then what would you say is normal for me to see in the 4000-5000 area? 30 degrees?

[V-M]

17 hours ago, Jayden M said:

If I have my base timing at say 10 degrees at idle then what would you say is normal for me to see in the 4000-5000 area? 30 degrees?

 

[SRDT]

Quote

The selection of the appropriate advance map is made by a pressure switch (fig. II) connected to the inlet manifold.

 

The upper curve (I) corresponds to a supercharge pressure below 100 mbars (1 1/2 lbf in²) (engine on light load).

 

The lower curve (II) corresponds to a supercharge pressure above 100 mbars (1 1/2 lbf in²) (engine on medium or full load).

 

[Jayden M]

I have seen those curves and information about a pressure switch somewhere before but I think that is for European cars. I dont think we have that pressure switch in america

[V-M]

Should be there? next to gauge sender? Number 3 is switch, note at for me it was stuck cause there was moisture which was reacting with sensor internals and rusted inside.

[Jayden M]

Don't think so. In US the coil is mounted vertically right there and I dont see anything like that.

[SRDT]

The dual curves ignition box and pressure switch are used on the 160 and 180 hp engines with intercooler and no cat. I think US models should have a Bosch EZK ignition ECU unless it's a non intercooled car.

[Jayden M]

All the US models have cats though. Iv not seen that pressure switch before and Iv gone looking for it before a few times.

[V-M]

Seem at kat versions has this EZ 200 K which looks information from knock sensor and lamda info and has no those pressure switches. I have some factory books about kat version. those are in germany lang but has good pictures.

[SRDT]

I can find 3 EZ200K variants:

5945.26 (0 227 400 033) form 01/86 up to 01/87

5945.46 (0 227 400 128 N9TEA 176W with boost control ?) from 01/87 up to MOD 89

5946.49 (0 227 400 153 N9TEA Wagon ?) since MOD 89

From the outside these ECUs are not visually similar to the Volvo or Saab EZKs, they seem to be closer to Alfa Romeo's EZ201K (75-Milano 1.8 turbo) and EZ212K (164/GTV 2.0 V6 turbo).