SNAFU; high performance 318is build that lives up to the name, Turbo M42 ➞ Turbo M20

[varg]

[varg]

Loving my car with the M20 swap. Sounds good, still handles great, much more torque.

The 4.10 diff has to go. First gear is only good for making 11s at WOT, I get 2nd gear wheelspin on dry pavement, and can spin them up in 4th in the wet if I'm abrupt with it. Seeking 2.93 LSD.

[varg]

370z nismo rated at 350ish?

Yes, and ~3,300lbs.

Just looked over this. Awesome read. Looking at getting those xxr wheels but just wondering how much you had to roll the fenders to get em to fit?

Thanks. I just had to roll the rear lip enough to fold it over, didn't have to push the fenders out at all. The rear tires rubbed on the lip when the car squatted, the front fender lip got bent out when I hit a big bump with the wheels turned, so the front should probably be rolled too.

[ThatM20Guy]

Just looked over this. Awesome read. Looking at getting those xxr wheels but just wondering how much you had to roll the fenders to get em to fit?

[fresh_TD]

I know it's faster than a 370Z Nismo though ;D

370z nismo rated at 350ish?

[varg]

How much power are you putting down at 13psi?

I know it's faster than a 370Z Nismo though ;D

[fresh_TD]

How much power are you putting down at 13psi?

[varg]

Took some more pics this weekend.















Ignore the low hanging charge piping which looks like ass. That's the only way I could get it to fit with what I had, and a custom pipe down the road will fix it.

I'm up to 13psi of boost now, and though my closed loop boost control isn't 100% dialed in I'm having fun with the car. 13psi is as high as I'm planning on going until I have the time and funds to rebuild the head and o-ring the engine, so if I'm going to make any more power it will be entirely in the fine tuning, leaning to the target AFR and maybe adding a little bit of timing advance to my conservative in-boost map.

If you ever feel like o-ringing the block, i can rent you the tool. I'm jealous of your tuning Knowledge, thats the only thing that scares me on my turbo build.

I would, but I've never o-ringed an engine before and don't plan on doing that part of it myself, I'll probably have John at WOT Tech do it. Tuning isn't hard, you just have to be methodical and it helps to ask other people and see what other people's maps look like with similar setups.

[johnr617]

If you ever feel like o-ringing the block, i can rent you the tool. I'm jealous of your tuning Knowledge, thats the only thing that scares me on my turbo build.

[varg]

Good to see you up and running again.
Big difference from the M42 huh..?

Sure is. I'm glad to finally have an M20, the torque is nice and there's the peace of mind of a more durable engine.

How did you vac plum your solenoid? Middle barb on the solenoid to atmosphere?
It's something I've been putting off for a few months now due to not knowing how to tune the tables for it really. Looks good.

It's a single port wastegate actuator so middle to wastegate, lower to compressor housing, upper open. If you don't have boost creep to deal with, tuning the open loop table is easy, it's all trial and error, closed loop control has been a pain in both of my setups I never got it perfect with the M42, it would either oscillate, overshoot, or be slow to rise.

[ak-]

How did you vac plum your solenoid? Middle barb on the solenoid to atmosphere?
It's something I've been putting off for a few months now due to not knowing how to tune the tables for it really. Looks good.

[Good & Tight]

Good to see you up and running again.
Big difference from the M42 huh..?

[varg]

In sound not spirit John. At least they're hypothetical hondas with extra cylinders ;)

[ForcedFirebird]

Spec e30's aren't near as bad as the Spec Miatas. I dies a little inside when you compared us to Hondas :(

[varg]

I reinstalled my boost control solenoid and started tuning the closed loop boost control again this week. It's kind of a pain, but it's almost there. I'm currently running around 10psi of boost, and am turning it up another pound tomorrow. Though I've added a degree of advance here and there in boost, this tune is going to stay conservative as long as I have a stock head gasket. I don't trust it. I am very happy with my exhaust though, the second muffler I added a while back is still worth the loss of ground clearance, the car is quieter with the M20 than it was with the M42, and has a nice deep sound with little of the awful rasp that is present in so many loud M20 cars. If you haven't heard a field of spec E30 cars I'd describe the sound as like a flock of civics which have been blessed with two extra cylinders each, or many, many bees.



Another decent shot of my engine bay. I'm going to do a valve adjustment and clean the aluminum up a bit in the next couple of weeks. I really want to get rid of the yellowing on the intake manifold, I like the look of clean cast aluminum.

I have two busted HX40 compressor wheels that I think I have plans for now...

Can you clock your compressor housing to move the outlet?
Or what I'm really asking, is can you move the wg actuator around the turbo?

In my particular case it just wouldn't fit (the arm should extend straight to the valve) so I had to cut the arm and put it there, it's far from ideal but it's working so far. The bracket is also for a T3, not a T4, so it is only held on by one bolt. Some turbos don't allow this kind of re-positioning, the actuators are bolted to the front of the housing or otherwise affixed to a spot other than the bolts holding the housing on. In the case of some holsets the actuator bolts to a bracket that is cast into the compressor housing, those are a pain to clock and use.