Hey guys, so I’ve almost got my car on the road. A little while ago I was on the dyno and the headgasket blew due to an improper installation. I just want to make sure that the actual tune itself is safe and didn’t likely cause the failure.
My engine setup is a 2.9L M20 with M52 crankshaft, VAC rods, 9.0:1 CP pistons, ARP hardware and studs, VAC cutting ring headgasket, and a built head.
I’m running a MS2PNP with wasted spark on US 91 equivalent fuel at around 10psi.
Here are some screenshots I took from TunerStudio:
Let me know if you have any questions. Any help will be greatly appreciated.
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Your ignition table is way to retarded everywhere and the VE table doesn't make any sense below 30 kpa. Beyond that the only way to tell is to start running it and tuning.
From 45kpa to 0kpa the a/f ratio should be between 14.7 and 15.2
Then richen up gradually as pressure rises, something like this:
45-70kpa target 14.3-14.5
70-80kpa target 14.0-14.3
80-90kpa target 13.8-14.0
90-100kpa target 13.3-13.7
100-125kpa target 12.8-13.3
125-150kpa target 12.3-12.8
150-175kpa target 11.8-12.3
To time it you would want to use EGT or a dynometer , and research how to find best average torque vs timing and controlling EGT
I’d like to add, that we didn’t really get to the WOT throttle stuff, it was mainly drivability tuning, but a few WOT pulls were made.
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drivability usually requires a smooth map. try looking at maps in 3D Graph view so you can see how terrible those are in terms of sudden changes.
Too rich and too retarded.
try running 20* and 12.5afr at that low of boost.
Last edited by cj.surr; 07-16-2018 at 05:31 PM.
Engine size is off.
Also did you verify that your timing is true?
https://www.diyautotune.com/support/...r/base-timing/
Also Matt Cramer has stated in the past that you typically need more resolution below 100kpa then you need above 100kpa. Ie driveability can be increased if you have more room to make adjustments. I suggest only using 5 or so rows for boost not 7.
Also you can increase driveability by changing to the 16x16 table vs the 12x12.
Last edited by euro2fast4u; 07-16-2018 at 05:42 PM.
Capital Driving Club Car # 102
How to turbo your car:
Step one. Install ecu and learn to tune and or have it tuned.
Step two. Install injectors and retune.
Step three. Install turbo parts and bits. get it running with out leaks. DO NOT DRIVE IT. Idling should be ok
Step four. Retune car
Step five enjoy
I will definitely let my tuner know. He did seem to “stress” about the drivability and smoothness aspect although I can’t confirm
The drivability because obviously the HG blew before I got to drive it.
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im actually surprised you managed to blow a cutring gasket....
Me too, but after I had the engine built we noticed some coolant seepage between the head and block, and thought it was just residual or part of heat cycling, but even a few months later, it seemed to have fresh leaks once in a while. So I guess it was only a matter of time before it blew.
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This started on my engine when I replaced the gasket this winter during a rebuild. My first one didn't do it. Now it seeps just enough to make a little crusty area where the head and block meet.
Between that and the cut rings lining up on the cylinders really poorly, I really think this will be my last JE cutring I use.
We've known for about 15 years now that the .140 mls gaskets are really unreliable on the M5X motors but your welcome to try your luck.
or use teh stock gasket and if ur tune is bad then it'll blow instead of the engine :P
That's what we all thought back in the day. People tried all kinds of finishing methods and they just kept failing. There is a reason all the guys here that have had turbo e36's for 10 years don't have them and never recommend them. A few people here and there get lucky with them. My personal theory is that an MLS gasket with that many layers cannot transfer the heat out of the middle layers through the viton coating out to the head and block and the viton coating scorches. They would probably be fine if people were only using .036" thick ones.
- - - Updated - - -
Stock head gasket and 11mm studs here. I have a cutring going in due to safety concerns this year.
UPDATE: the head was finally pulled off today, and we discovered that the head cracked even though it has welded coolant jackets. I’m gonna throw in a new head and put it back together, then let my tuner finish the tune and go from there.
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Back in the day when my friend and I first turbo charged his M20 (this was like 8 years ago)... we also were told we HAD to weld the coolant ports on the head.
A couple motors later, we didn't bother anymore and we were making more power.
As usual old fairy tales from long ago when people didn't quite have things figured out is generally not needed anymore.
v
v
v
KorreCT
A few "perfect" (lucky) installs didn't represent the larger frustrated crowd of failing/leaky MLS gaskets back then,
hence the reason for ELRING with o-ring or cutting rings becoming the easy/reliable option.
lol
welding coolant ports...to "mend" the failure spot of the MLS.
Who is your tuner? I'm in Langley and in the process of building a stroker motor that I will need the ECU tuned for, there's a local place that's been recommended but always good to have options.
I'm going turbo eventually, only 350ish hp max though and the car may get drag raced once or twice but it'll basically just be a daily driver so I went with a .07 MLS gasket. Getting the head and block properly prepped for it, my mechanic friend says they're bullet proof if you do it properly. Time will tell.
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