Hoffbro's Scheisse-rot Turbo

[Hoffbrohaus]

Rescheduled exhaust install for 12/21. Tuner of course can't get me in until after the new year. So question for the Megasquirt experts out there, does my initial tuning look OK? Panici varg ForcedFirebird Dj Buttchug

I'm using the DIYAuto EBC, so in tuner studio set it to open loop with a max boost of 200kPa


Then set the boost control table to all zeroes since my wastegate spring is at 11lbs.


Used this video to help start the fuel table settings before I get to the tuner.
Megasquirt Table Scaling Basics | NA to Boosted Tune Made Easy (youtube.com)


When I save the Fuel VE Table it displays the Y axis as PSI, did I change that somewhere? I want it as kPa



Does this look good enough to drive to the muffler shop and tuner with? Also why in the tuning video above does he say 14psi = 1bar = 200kPa? When I google "convert 14psi to kPa" I get 100kpa, guessing I have to adjust for my altitude?

[Hoffbrohaus]

So I got the muffler done! Late last night so I only got to drive home. Couldn't sleep because I was so excited to start tuning. On my way home I couldn't help but try to boost a little. But I couldn't get any boost. 😡

So I noticed as I drove I could hear what sounded like exhaust coming out a big straw, has to be the dump pipe. The wastegate must be opening immediately or is stuck open.

So I took the wastegate off and I won't go through the trouble shooting process because it took like 60 seconds to figure out what was wrong. Newbie mistake.

Don't roast me please 😁 For all those new to external wastegates like me don't assume the vacuum fittings go in the open holes it ships with. The side hole and top hole were open but those are really both on the top just different positions. So you need to swap the plug lower on the side with the vacuum fitting. Duh


Battery is charging so I'll go test in a little bit.

[Hoffbrohaus]

Never rains in Phoenix but it's been raining all day today. Took it out for a bit and built boost, tires were spinning on the wet roads 😁 I'm good to go for tuning.

[varg]

There's a preferred units option under the options drop down which will convert your Y axis to PSI. 100kPa is 14.5psi, 1atm is 101.3kPa or 14.7psi. Up in Phoenix I wouldn't expect 1atm with the engine off since you're probably close to 1000' asl. As for whether it's good enough to drive that depends on how it runs.

[Hoffbrohaus]

There's a preferred units option under the options drop down which will convert your Y axis to PSI. 100kPa is 14.5psi, 1atm is 101.3kPa or 14.7psi. Up in Phoenix I wouldn't expect 1atm with the engine off since you're probably close to 1000' asl. As for whether it's good enough to drive that depends on how it runs.

Thanks varg, car is running great, just didn't want to blow anything up before I went to the tuner. It's hard to not boost just a little 😁

So here's my confusion with kPa to psi conversion. Yes 100 kPa converts to 14.7psi, so why when I put 100 kPa as my top y axis value it shows it as 0 psi? The guy in the video puts his top at 200 and that converts in the boost table to 18 psi. But in reality 200kPa is 29psi.

btw here is the setting in tuner studio in case anyone else is looking for it:

[mikey.antonakakis]

Be careful with that fuel map - you've got a big dip above 90kPa. Fuel table load axis is based on MAP sensor, guessing in Phoenix you're around 90kPa (sea level is 101kPa). At least do an interpolation on the 100kPa row. You can check your atmospheric pressure by just reading the MAP value with key on/engine off and TunerStudio open. Or get the MAPDaddy or whatever they call it, it has a barometric sensor built in :)

As for the wastegate, plumbing the vacuum line to the top port will prevent the wastegate from ever opening (more boost -> more pressure holding the wastegate shut). If you couldn't build boost, that wasn't the issue, it was probably the wastegate being stuck open for some reason.

[McGyver]

Thanks varg, car is running great, just didn't want to blow anything up before I went to the tuner. It's hard to not boost just a little 😁

So here's my confusion with kPa to psi conversion. Yes 100 kPa converts to 14.7psi, so why when I put 100 kPa as my top y axis value it shows it as 0 psi? The guy in the video puts his top at 200 and that converts in the boost table to 18 psi. But in reality 200kPa is 29psi.

btw here is the setting in tuner studio in case anyone else is looking for it:

I'd have to re-read the tuner studio manual to know for sure, but is this an issue of confusing Gage Pressure with Absolute Pressure? Gage shows a pressure differential from absolute pressure, which should be around 14.7psi (depending on local factors).

[Hoffbrohaus]

That's probably what it is. That make sense to have a difference between absolute and gauge.

I figured out some of my boost problems. I had some small leaks at some couplers I temporarily put in while my welder was working on my charge pipe.

So.... Mikey's advice came too late. It was Christmas break, I fixed boost leaks, couldn't wait for tuner appointment so I went out. Pushed 10psi and blew the head gasket. 😭😭😭

So that sucks. But the silver lining(s) are 1. Slowed me down and reminded me patience. 2. I get to change the timing belt and water pump, so that won't be an issue and 3. I'll get an MLS gasket to really be secure in my boosting.

Current state. Almost got the head off, just got hit with a bad day of Covid today so couldn't do anymore.

[mikey.antonakakis]

Ah bummer!
Personally I would avoid MLS and stay with a (good, like Goetze) stock HG. As you just learned, it’s an effective fuse that prevents further engine destruction, and with a good tune it will handle lots of power. With a bad tune MLS won’t totally prevent issues and you might not know it until the head cracks or something. So, no matter what you do, don’t turn up the boost until you know you’ve got a good tune and reliable fuel system.

[Hoffbrohaus]

Ah bummer!
Personally I would avoid MLS and stay with a (good, like Goetze) stock HG. As you just learned, it's an effective fuse that prevents further engine destruction,

Great point. I was thinking things could have been much worse. I think I will go with a Gotze HG.

I got the head off today. Pistons look good, just some gunk and debris.


Next I guess I'll take the exhaust manifold and intake plenum off. Then the plugs and injectors. Then I need to find a good shop in Phoenix to resurface the head.



While I have access do you think it's worth my time replacing the starter motor? Nothing wrong with it just the original and doesn't look so good.

[Dj Buttchug]

Id say leave the starter in there if its not giving any issues. I cant recall ever needing a starter on any of my builds and most of them looked exactly as yours does. Maybe take it out and clean it up if you want. OEM is far better than any aftermarket replacement youll get at vatozone these days.

Im interested to know how flat your cylinder head is. Unless you are really pounding on the car untuned you shouldnt be popping HGs. In any case, getting a machine shop to plane the head will be a good move.

[Hoffbrohaus]

Im interested to know how flat your cylinder head is. Unless you are really pounding on the car untuned you shouldnt be popping HGs. In any case, getting a machine shop to plane the head will be a good move.

Putting a straight edge on the head it looks nice and flat. So not worried about that. I do have 2 other concerns though.

When I removed the head of course I lined up the vibration damper and cam sprocket to TDC. I thought at top dead center all valves were closed? My #2 cylinder has the exhaust valve open and #3 the intake valve. Does this mean the cam is misaligned?

Also, can the machine shop Resurface the head with the cams and valves in there? Probably need to get all the valves closed I would think.

[McGyver]

It doesn't take much time for a machine shop to disassemble the head so it can be fully cleaned. Or you could do it to lap in the valves and change the valve seal guides.

It may be able to be machined with the valves in place, but I assume at least the cam has to be out so all valves will be closed, otherwise some will be past the bottom surface of the head.

[mikey.antonakakis]

With an inline 6, you'll never have all valves closed at the same time. It also makes getting the cam/rocker shafts out a little tricky on the M20, since some of the valve springs will always be under tension.

[Panici]

Oof sorry to hear about the HG failure.
Too late now, but you want to take things slowly for best results when boosting.
Base maps are really just meant to get a car started, not into boost.


I learned to tune on my M52 when it was N/A. Then when boosted I started with a 4psi WG spring and made sure to get the maps and knock detection dialed in before adding boost.

Heck, coming up on season 3 of boost now and still haven't gone above 7psi. Although I did just add a turbosmart manual boost controller