Another head gasket question

[turbski]

So finally made it to the dyno this past wed. Everything was going great. Had some issues making to much boost due to routing the lines for external waste gate to the wrong ports on the ebc. Ended up getting it squared away. Then realized we blew a coolant line. Not a big deal right? Repaired and tried again. This time coolant trying to blow the rad tank cap off. . . . figure its obv head gasket.

Question is what is the best setup or brand? The one that we popped is cometic mls. .080".

Its running 6lbs of boost with hopes for more and put down 320whp.
Let me know what's out there.
Yes it has arp studs

[Cayoncrusier93]

Did you properly get the head and block machined to the surface needed to bite onto the MLS gasket? I hear sometimes that can be an issue. Maybe your issue of making too much boost the first time started pushing it out and when you went for the second run it finally did it.

[turbski]

No, I did not assemble the engine, I know the head was machined but do not believe the block was out of the car. In talking with the previous owner, he felt as though the mls coupled with the overboost could have resulted in what we saw, (as you pointed out) what I am leaning towards after talking with him and a little reading is going back to an oem gasket?? I have found a few that look promising. I have even found 1 company that makes 1 that is oem material coupled with stainless floating rings. not sure if ill go that route but would like to know what my options are. The car made more than enough power for what I want it for at this time so im not super concerned with upping the boost levels in the near future.

[Tonybeemer]

What is you’re setup ? You’re making 320hp on 6psi? Is this to the wheels ?? What’s done to the motor ?

[Tonybeemer]

To answer you’re question ., stock head gasket and o-ring block you won’t have head gasket issues

[turbski]

42lb injectors. Holset turbo. Megasquirt 2 fuel and ignition. Gm coil packs. The boost level I'm not 100% convinced on. The log shows 6psi but my mech gauge showed closer to 11psi. Not sure why. I will post the dyno graph asap. I will also be gushing each head stud I pulled for signs of stretch. They were used to my knowledge min 5 times.

[turbski]

dyno graph


I think I did this correctly. let me know if it shows up

[citizen_insane]

6psi sounds low to be making 300 at the wheels, 11 sounds more like it. Was it the MS log that was showing only 6? That seems pretty strange assuming you're running MAP. If the sensor was low, the engine would not have received enough fuel.

Or was pressure being measured by another pressure gauge and logged on the dyno?

[turbski]

That's what is strange. He had the dyno hooked into my vac system. Both the dyno and logs from my car show 6 and my guage shows 10ish. The dyno run above is all his instruments measuring what the car put down. I think it looks like just shy of 7psi running off spring pressure only. End was off.

[turbski]

Sorry. He had his computer hooked into my ms system and another line into my vac system.

[citizen_insane]

As much as I'd like to trust two separate independent measurements, my matching for the M20 suggests you'd need ~15psi to reach those targets. My pressure losses haven't been calibrated to an actual engine yet, but they are reasonable assumptions. I don't see how you could possibly make 300hp @5500rpm w/ only 7psi.

Logically, if you're doubling the power output of the engine at that point, you need to double the density of the air going into the engine. A 50% increase isn't going to cut it.

[turbski]

My thoughts as well. 6_7 psi seems low to put down what is registered in the dyno graph above. But the numbers are there. Ill have to switch out my mech gauge before I go back to the dyno.

My new arp studs will be in tomorrow then its just a matter of putting the head gasket in and taking it for a rip lol

[Jaxx_]

what does the megasquirt say? What is the max kPa? You can convert it to psi boost. Just do a full throttle log and see what the peak is.

180kpa is ~11psi,
135kpa is ~5psi.

[turbski]

ill log it Saturday afternoon. I guess I was just wondering if the ms unit could be off. I did ask the tuner this question, his response was pretty simple, ign on, key off, does it read about 100 kpa?.... if so its fine. it did.

it looks as though while trying to view the gauge under WOT its shy of ten by a CH.

At this point im just happy to be able to drive it with a tune that's safe and actually get to feel what its like when the tune is correct. This is my first e30,

so far ive done, head gasket, output shaft seal, had the bumper and front lip off 30 times (I just wasn't happy with the alignment lol) valve adjustment, and will be doing a complete suspension rebuild over the winter when its stuck in the garage.

all the help ive gotten here has been huge.

Also, I had bought 2 head gaskets, 1 victor reinz and 1 goetze. I put the latter in as it had a much more robust feel.