My Other DIY Project.

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shawn_g
Posts: 386
Joined: Sat Jan 14, 2012 9:00 pm
Location: Logan, OH

Re: My Other DIY Project.

#121 Post by shawn_g »

bassmonster wrote: Wow, that's pretty quick. I enjoyed the sound of the Megan exhaust on some of your other videos.

To be honest, I would love to tune it myself, but where should I begin? I know the basic logic of the ECU as it pertains to knock control and AFR sensing, but I don't know which tables to modify first, and I don't know how I should modify them. Should I start with rescaling the MAF sensor, then pulling ~20 degrees of timing across the board then gradually making changes in fueling? I guess I should just bite the bullet and get a pro-tune, but being able to tune it myself would be really neat.
I felt overwhelmed the first time I fired up romraider. There are just so many things that can go wrong. You probably will need to rescale your MAF and I think there are some spreadsheets out there that should help with that. If you're running the stock map, it's probably running lean and with timing that's fine for N/A, but not forced induction.

I had the benefit of having a well supported car that is already turbo, so it was relatively easy for me to get a basic tune on there. Here's the basics:

-Open the Open Loop fuel table and add some more fuel for higher engine load and higher rpm areas. Anywhere that you're not making boost shouldn't need any changes. Don't go crazy, but you'll want to richen it up in the higher boost, higher rpm areas for safety. You should probably aim for around 10.5:1 at the highest load above 4000rpm and maybe go down to 10:1 at redline. The key is to make everything nice and gradual/smooth. If you take it to get a real tune, they'll hook a wideband O2 up and probably lean it out more, but without a wideband, it's safer to run rich for now.

-Open the Ignition base tables and drop around 10 to 15 degrees of timing in the higher engine load (>2g) higher rpm (>5000rpm) areas. Then adjust the surrounding cells to make a nice gradual change anywhere you're making boost. Obviously you won't need to pull as much timing in the low rpm or low engine load areas, so you'll just need to use some common sense and look at the stock value and adjust it proportionally. Kind of the same deal with the fuel tables.

-Open your logger and log RPM, load, knock sum, throttle %. Drive around for a while and don't be overly concerned about the off-idle or throttle tip-in knocks. Do a few pulls and see if the knock sum increases. If you see a knock at say 2.0g/5000rpm, go to that cell and decrease the timing on that cell by 3 to 5 degrees and the surrounding cells.

-If you don't have any knocks on the pulls, increase the timing in the boost areas a small amount at a time. If you start seeing any knocks at all, decrease the timing in that area to be safe. You'll want to go for a "safe" tune by keeping the timing values at least ~5 degrees below the point where it might knock.

Tuning is one of those things that's really difficult to explain over the internet. There are a lot of good resources out there. If you can find a stage 2 base map for a WRX or Forester XT, that might give you a good reference point for your own map. The worst part about open source tuning is the constant reflashing. I'm probably on revision 30 on my map. :shock:

bassmonster
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Re: My Other DIY Project.

#122 Post by bassmonster »

Excellent write-up, thanks. I'll look into it when I get back. Unfortunately a regular turbo map won't work for me because I'm higher compression and only running 3 psi right now. I get nearly full boost at 2200 RPM, though. :mrgreen: I've flashed to my car only once, that was a stock map that deleted the PO502 speed sensor low input CEL. That's a scary experience knowing you will brick it if there is a malfunction. :shock:

bassmonster
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Re: My Other DIY Project.

#123 Post by bassmonster »

Well, I took the advice and started tuning myself. I created a low timing/rich AFR map and began logging. My car felt really slow, but IAMs went back up to 1.0.

Unfortunately, I got in a crash on my motorized bicycle a week ago and smashed my left first metacarpal, so I won't be able to ride or drive my car for another 7 weeks. The crash itself was pretty gnarly. I was turning a blind left at about 25 mph :wall: and an SUV appeared so I hit the brakes, and the thin front tire slid out from under me. I smacked my hand on the pavement, then I slid off the road and flipped sideways over the bike and smashed backwards through a fence. It must have looked insane as a bystander. I have some pretty good road rash on my right leg too. Oh well, it could have been worse, and now that I've laid it down bad, I'll never crash it again! :mrgreen: :bull:

:owned:

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: My Other DIY Project.

#124 Post by Tom Smit »

Oh man!
Hope you heal up well, soon.
TomS

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shawn_g
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Joined: Sat Jan 14, 2012 9:00 pm
Location: Logan, OH

Re: My Other DIY Project.

#125 Post by shawn_g »

Hope you have a quick recovery.

Sounds like a good start on the tuning, hopefully you can dial some of the power back in without hurting the IAM.

bassmonster
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Re: My Other DIY Project.

#126 Post by bassmonster »

Well, my hand healed fine, but two days after I got back on the road, my car overheated badly, so there goes the head gaskets....after 3000 miles.


I took that to mean "built motor time" so I'm getting an EJ255 short block, to which I will mount my SOHC heads for a hybrid motor build. Time for 9:1 compression and a lot more boost. :twisted:

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shawn_g
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Location: Logan, OH

Re: My Other DIY Project.

#127 Post by shawn_g »

bassmonster wrote:Well, my hand healed fine, but two days after I got back on the road, my car overheated badly, so there goes the head gaskets....after 3000 miles.


I took that to mean "built motor time" so I'm getting an EJ255 short block, to which I will mount my SOHC heads for a hybrid motor build. Time for 9:1 compression and a lot more boost. :twisted:
Good luck on the new build!

I blew a headgasket on my old WRX. Pulled the motor and fixed it, then had a rod bearing give out 20k miles later. :x

bassmonster
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Re: My Other DIY Project.

#128 Post by bassmonster »

Onto the motor swap. Ended up scoring an EJ257 shortblock with 80K miles, inspected it and it looks good. I'm doing a hybrid build with my EJ253 heads for 9:1 compression. This will yield a little less low end than the original 10:1 compression, but I can run more boost. The 253 heads are the best flowing heads Subaru makes, and they're getting rebuilt and milled at the machine shop right now. I pulled the motor in my garage for the second time with just a set of socket wrenches and an engine crane, took me about 4 hours total.

Onto the pics!

Image


Here's where the Felpro MLS headgaskets failed catastrophically, I'm going with OEM STi headgaskets for the hybrid motor:

Image

Here's the stripped EJ253 shortblock, I'm putting it up for sale noting that it needs to be milled:

Image

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shawn_g
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Re: My Other DIY Project.

#129 Post by shawn_g »

Sounds like a good upgrade. Hopefully the tuning will be a little easier with lower compression.

bassmonster
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Re: My Other DIY Project.

#130 Post by bassmonster »

Well, the motor's back in and running well! The rebuilt heads were beautiful, pics of everything to come later. I did everything right with this swap- rebuilt heads, OEM STi head gaskets and new OEM head bolts, replacing gaskets everywhere I could, new fuel pump, new fuel filter, etc. I dropped some good coin with this but it should run much more reliably now.

So far it feels good. I still have a vacuum leak at idle, but it's drivable. I just need to get working on the tuning now.

bassmonster
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Re: My Other DIY Project.

#131 Post by bassmonster »

Apologies for the portrait-style filming :horse:



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shawn_g
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Location: Logan, OH

Re: My Other DIY Project.

#132 Post by shawn_g »

That first startup is always nerve racking.

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