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VGT M20 Build - HE351VE

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    Originally posted by mikey.antonakakis View Post
    Social distancing has been a huge help to the project. Car is running! Still need to make the downpipe-back exhaust and an intercooler reservoir.
    The electronics/coding on this project has been big... maybe I'll start a new thread with all the details in the projects forum, since a lot of it is outside the scope of forced induction. I should have plenty of time for a writeup soon.
    The last week or two has been a whirlwind, but the time and the cheap gas are an odd silver lining.
    I'd love to read a writeup on what all you've had to do to get it running, I'm running a regular HE351 so I have been enjoying this thread.


      Had a few bugs to work out, many left from the last time the car was running ~4 years ago. As of last night, car seems to be running properly now, so I'll have some more info, hopefully a video, soon!


        I'll have more info later, but here's a quick snapshot for now. This was a second and partial third gear pull, ~6000ft elevation, uphill at maybe 4% grade. Wastegate set to about 155kPa absolute (~10.5psi gauge, would be ~8psi at sea level). I have a 2.93 rear end, so I hit the throttle ~32mph in 2nd, lifted at ~93mph in third ~8.5s later. Shift was somewhat lazy, ~0.65s. I had flat shifting turned off here - it would be quite a bit quicker shift with it on, and I would have obviously held boost a lot better. But easier to tune with it off.

        Back-of-the-envelope (okay, Excel) calculation including estimate of aero drag shows pretty consistent 270+whp at just 8psi... I'm pretty happy with that for now! Ultimately plan to run about 15psi (absolute, so about 200kPa absolute).

        This pull in the below datalog was one of the lowest calculated power pulls, ~260whp, but it was uphill - on one downhill run it worked out to 320whp. Cam is advanced about as far as I want it to go, so I should be able to get more top end if I want. But for now I'm working on mostly drivability and making sure the ignition map is safe (I added a knock sensor to the forward starter bracket boss on the block, built an amp for it, and added a bandpass filter from 5.5kHz to 8kHz). Today I finally got rid of all discernible knock, in part due to more aggressive MAT retard. I may have room for more timing at high RPM. Inlet air temp maxed out at 112F at the end of this pull, with about 70deg ambient temp after lots of driving (and this pull was right after a short heat soak of a couple minutes).

        Boost target is set a little lower than wastegate to force the PID to open the vanes fully once it's mostly spooled.
        Click image for larger version

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          Originally posted by mikey.antonakakis View Post

          ...But for now I'm working on mostly drivability and making sure the ignition map is safe (I added a knock sensor to the forward starter bracket boss on the block, built an amp for it, and added a bandpass filter from 5.5kHz to 8kHz).

          Where exactly is the forward starter bracket boss? I'm currently trying to decide where to locate a sensor and if that position is working good for you then I would love to emulate it.


            Depending on the starter, it uses either two or three mounting bolts - two on the bellhousing, always, and some have a bracket that bolts to the front end (towards radiator) of the starter. The bracket has two bolts on the starter, a 90deg bend, and bolts to a 10mm threaded boss in the block, right under the freeze plug at the #4 cylinder. You can see it just barely peeking out from behind the dipstick (near the dipstick clamp/bracket) in this pic (not my engine, but my block looks the same).
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            I found a random knock sensor with a Bosch EV1 connector for like $16 from Advance Auto, it has an 8mm hole, so I had to hack up a couple bolts to make a stud to convert from 10mm (going into the block) to 8mm (going through the starter bracket and knock sensor).


              Fantastic, thanks! I was also thinking just get whatever Bosch is cheap and available, but maybe I will try to prioritize finding one with a 10mm hole.


                After analyzing more datalogs, and finding whatever info I can on the turbo, seems like I've reached the surge limit around 3000rpm with my latest VGT tuning. I think it'll be a pretty fine line to walk at these low revs - as you can see, vanes close pretty tight to get the turbo spooling, but then it hits a boost/speed wall - but as soon as the vanes start opening a bit more, turbo speed and boost start climbing again (then I get out of the throttle). Note that despite the low MAP, pressure ratio is a reasonable 1.6, due to my 80kPa barometric pressure here in Colorado.

                Click image for larger version

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