patsmx5

iTrader: (16)

Ok so made a little progress today. Literally in Post 2 Dann mentioned spark retard rev limit and I in post 3 said that's what it feels like but I didn't have one setup.

Well today I found a place in the middle of nowhere where i could hook up a timing light and rev the engine to 7K or so and check to see if it's holding timing the same. It was not!

I fixed the timing and it retarded 4 degrees by 6,800 RPM. It appeared to be a very linear delay. So I did some quick math and calculated it's about 25 microseconds between each crank degree at 6,800 RPM, and I'm 4 degrees off so I put 100 micro second delay in MS3 Ignition options for the latency (it was previously at zero). That fixed that issue, it stays within 1 degree now. Drove it and it's better! Top end feels better.

Also this means all my previous post where I said I was running 10, or 14 degrees, I was actually running 4 LESS than THAT!

VD: Pink trace is latest after fixing the latency, no other changes made.



Datalog of this pull. It was a short pull, it's all I could get in.


Number aren't up much, but it's much better at higher RPM than before, it's actually doing something up top as compared to before. Peak was at 6,418, but at 7,588 it was at 226, which is 94.5% of peak power. Not where I want to be, but at least going in the right direction.

I'm about to go pull the plugs now and have a look. One seat-of-the-pants observation is that the motor now revs REALLY quick compared to before in neutral.

Also it went to 7,655 RPM and made 21 PSI. I haven't went this high yet, so now i gotta redo my tables to to go 8K or more. Fuel was really fat up there so that needs to be fixed of course.

18psi

iTrader: (76)

congrats, progress is always good. power definitely looks to have picked up. if that fixed it, now you can start actually leaning on this thing and see what it really will make

patsmx5

iTrader: (16)

Yes sir! Numbers still seem low given the amount of air and fuel I'm burning. I think it needs more timing. I'm letting the car cool down then I'm gonna pull plugs and check them, and also swap the alternator out for my stock one.

Now I'm gonna redo all my tables to go to 8K or so.

patsmx5

iTrader: (16)

Well I went and bought a 9x magnifying glass and pulled the plugs. They look clean. I can't see any signs of detonation. I'm redoing my tables right now to go to 8K then going to add probably 1 degree of timing and see how it does. Maybe 2. Currently at about 16 degrees advance at 21 PSI.

curly

iTrader: (25)

This guy, what a guy. Just spectacular. Absolute genious.

patsmx5

iTrader: (16)

But I am running the stock 4 tooth.... But yes the latency being zero did not work correctly! I won't pretend I know why, I don't, but 100 microseconds fixed that problem.

patsmx5

iTrader: (16)

Ok I'm having an issue, the rev limiter is kicking in wayyy to early. I had it set at 8,000 and it kicked in around 7500. Set it at 8,500 and it kicks in around 7,700.

Why? This makes no sense! Progressive fuel cut is OFF, it's just a regular fuel cut limiter, nothing else.

patsmx5

iTrader: (16)

Scratch the rev limter crap, turns out "overboost" protection was set at 250 kPa.

Good news: Making >250kPa now.

patsmx5

iTrader: (16)

Not sure about this, but it happened.

Green was first pull, light blue was a few minutes after it, same exact tune, same gear. No idea what happened, but green pull I felt it take off at 7K then it hit the limiter. Hit limiter on blue line too.

Changes were +1 degree timing, changed VVT a bit (didn't help really).

What could cause this????



EDIT: I turned smoothing off and after looking at the raw data I think this spike up is BS. With smoothing off if you draw a line of best fit it looks like 250whp not 300.

deezums

iTrader: (3)

Backwards power!

Are you manually editing the logs? I think VD might be plotting some irrelevant data.

It seems you are down on power everywhere, but you momentarily got to see all of it?

Are you sure the belt slip is fixed?

patsmx5

iTrader: (16)

I haven't edited the logs, I don't know how to do so. If you open them in notepad they look crazy.

I'm not sure belt slip is fixed actually. It's much better, but could still be slipping.

Yes it seems I did momentarily get to see the power! But I don't know what changed. Logs show everything was the same...

I'm wondering if it's something in the ignition system. But I don't know what else to check. I feel like I'm grasping at straws guessing.

18psi

iTrader: (76)

bump in the road or spike in the log

deezums

iTrader: (3)

If you have excel/open office calc you should be able to open the logs, I think they are .CSV format. Might have to right click open as or rename the .msl to .csv. I use megalog viewer to find the timestamp range I'm looking for.

patsmx5

iTrader: (16)

Well I pulled the plugs and they look different now. I'm finally seeing some color on the straps. Looks like it needs 2-3 degrees more timing based on the straps. I'm going to add 1 degree tomorrow and see how that does. Looks like I'll end up around 20 degrees if I can get it all in without detonation.

Still I don't expect it's going to gain a ton of power with 3 degrees.

patsmx5

iTrader: (16)

Serious question, are ANY of the guys making this power running VVT heads?

Cause a lot of the high power SC guys, and most of the high-power turbo guys I've seen are all running 99' heads, not VVT.

I'm honestly starting to wonder what the bottleneck is... and cams does seem possible.

curly

iTrader: (25)

I made 350 with blaen99's vvt head.

arghx7

Post your VVT map. I'm hoping to see you are at 0 degrees cam advance by like 4000 rpm and up.

When it comes to cams it's not the same with a blower vs a turbo. The nominal horsepower bottleneck limit with a turbo doesn't have much to do with a supercharged or n/a setup.

So-and-so made x peak power on stock cams with a turbo has very little to do with the rpm at which torque drops off on a supercharger or n/a. The gas exchange dynamics are different and the airflow from the blower is fixed according to the compressor map and the speed of the rotors (pulley speed). There's way less backpressure and very different tuning effects and cylinder balancing on a blower.

patsmx5

iTrader: (16)

I have two VVT maps. I'll post the one I WAS running, then I'll post the one I tried last night

Old map:


New map:


Datalogs and VD are in disagreement on which one is better.

Datalogs show that when I went to the new map, when at 4,800 when the cam went full retard, AFRs went rich (hinting at less airflow) AND boost went up 1.6 PSI (hinting more restriction/less airflow)

However, VD shows that, compared to a similar run where power was close up to 4,800, the new VVT map shows +20 HP beginning right around 5K... And that certainly says the motor likes the intake cam at the fully retarded position by ~5,000.

However the new VVT table also had 1 degree more ignition advance, so I don't know for sure... What I get for changing 2 things at once!

And yes I agree completely on what you said about cams.

Like I mentioned if I can confirm the car makes more power at say, 5,000 with the cam full retarded vs any other setting, that certainly suggest that if whatever valve closing event is optimal for 5,000 is the "fully retarded" position, that further retarding of the intake cam would be beneficial at RPMs > 5,000.

patsmx5

iTrader: (16)

Upon further thought, I may can explain around the "higher boost" and "richer AFRs" part.

Perhaps when the cam went fully retarded, less boost is "leaking" due to overlap, thus more boost.

And since less boost is leaking during overlap "aka unburned fuel/air mixture", there is less raw air in the exhaust that didn't get burned, thus the richer AFR reading now.

Possible.....

Also in theory more overlap is better for the SC setup, but I believe at higher RPMs, the intake valve closing event is more important thus why I saw the gain in HP when retarding the cam.

arghx7

You've got to put this on a loading dyno. You are reaching the limits of street tuning, and simple dynojet transient pulls won't cut it.