underdog

iTrader: (6)

Thanks everyone. I figured the 4G63 ECU thing would get some attention.

The ECU I'm running is a 1991 EPROM. The keen-eyed folk noticed right away that I don't have a DSM mass airflow sensor, this is only because I had a spare DSM HKS VPC and decided to use that until I get a new version of DSMlink. For those not into ancient DSM piggybacks, the VPC converts it to a MAP setup, allowing you to run without a MAS, etc. The EPROM chip in the ECU is a custom KeyDiver one that I had laying around from way back that is optimized for 550cc injectors and the VPC.

The knock correction is all built into the ECU and works beautifully. It really is how I've been able to go fast with such simple setups on 4G63 powered cars in the past. I've always just logged knock using Technomtive datalogger, which is a dead simple tool that's been around forever. I mean, I monitor other parameters, but when it comes down to it, the knock sensor tells you everything you need to know at WOT.

Thanks again guys, the thing started up on the first try and it amazes me how well it runs on this ECU. No stumbles, high idles, or any other weirdness, the dang car should've came with this thing from the factory!

Nagase

iTrader: (6)

Waaaaannt.

underdog

iTrader: (6)

Oh, you definitely called it! The stakes are so low with these turbos though, you can afford to experiment a bit. I just wish these chinacharger guys would become a little more sophisticated with their specs. I've seen a lot of crap on ebay such as photos/descriptions not matching, inconsistent info, etc. My turbo mentioned nothing of "Godspeed" on the auction yet had a Godspeed part number.

Thanks for posting all of your China T3 50 trim dyno info and boost data, it was very helpful. I almost bought this turbo from the beginning, based on your experience, but the allure of the super-cheap bigger turbo was too strong to pass up.

wildfire0310

iTrader: (1)

Wow talk about having a nice little system of parts laying around your garage.

Question did you have to do a lot or rewiring or bloomslang? I doubt it would be a plug and play. Also how did the 4g Throttle Body body up, pnp or did you have to drill and tap the manifold?

underdog

iTrader: (6)

Yes, I have quite the DSM/Mitsu stockpile. Heck, when I lived in Florida, I got most of this stuff for free! Keeping old parts is a pain, but as long as you keep them organized and catalog what you have, you'll be glad you did. I learned this from growing up around auto mechanics and my uncle who was in the auto salvage business.

I considered using a boomslang harness and rewiring the car, but there are enough differences between the two ECUs that made that path a more daunting project than I was prepared to take on. For example, the Miata engine management electronics are closer to the 1990 DSM setup than the far superior 1991-up. So to rewire you'd likely have to use the 1990 stuff which is a real compromise on a few fronts. Plus, I didn't want this to be permanent, I wanted to be able to go back to stock if needed. The approach I took was to use only the essential wires from the DSM engine harness and tap into select wires from the Miata ECU. Not as elegant, but it works great and it would take a trained eye to find it in the engine bay.

For the throttle body, the Mazda and DSM are very similar units but it isn't a bolt on. The DSM is a square pattern, while the Miata's pattern is close at the top but a bit wider at the bottom. To get it to work, I modified the DSM throttle body bolt holes. What made the job easier was the Miata bottom intake mounting holes are not tapped, so I had flexibility there. A big, weird project indeed. I learned a lot too. Just a little word of advice, a Megasquirt is ideal for 99.9% of the populous.

The McDonald's iced coffee was an important component to this project. I don't eat their food, but the coffee is pretty good. In this picture I'm swapping out the coil packs from the DSM bracket to the Miata bracket. I was also doing some other stuff, which explains the schematics. God, the internet has made the car hobby so much more fun and affordable.


Here's a couple pictures of the "test bench" I used to make sure it all worked. You can see the DSM mass airflow sensor I used. The Miata was non-turbo at the time, I did this part of the project pre-turbo for simplicity's sake. It ran great like this, I just couldn't drive too far.


The laptop wasn't required, I was just monitoring all of the sensors.


Here's a sample TMO/DSM datalog. This isn't mine, I just found it using a quick Google search to give y'all an idea. It's very simple and effective. You can choose to view the parameters you want on each log. FYI - the knock counts are measured as a number from 0-43 and you can see the correction happen in the log (more fuel added, timing removed) as the counts increase.

viperormiata

iTrader: (24)

That is very, very impressive.

Beautiful car too.

Deatschwerks

I think what gets most people on the video is how fast you shift. Most people can't shift that fast...and since they can't do it, it must be fake/sped up. :P

Not usually a fan of yellow, but it just seems to work with your car. If the budget allows, I'd suggest some 6ULs for your car. The nickel finish would look great under that yellow.

underdog

iTrader: (6)

I agree, it looked weird when I watched it the first time too. I guess I've been shifting fast for a long time. You have to with these small displacement turbo engines. Since we've been talking about dataloggers, I've used it combined with video to improve my speed and technique for some time. I'm still lifting off the gas though, no powershifting. I'm sure that I shift way faster in the video below, but something makes it look more natural here. My hair is definitely not flowing in the breeze with my big SpaceBalls helmet on - maybe that's it. I'm kinda hidden by the big SRT-4 seats too.



Thanks, I need some 6ULs in the worst way! A nice set of those, good tires and some suspension stuff are next on the list.

Deatschwerks

I have a set of the first gen on my CRX. Love them! For the longest time that was the only wheel that a 225/45-15 Hoosier actually sat right.

The good thing about the CRX and the Miata. The wheels are interchangeable.

underdog

iTrader: (6)

Now we're cookin! I went out datalogging and am very happy with the results so far. I was running 10-11psi and although it is hot as heck here, it was pulling nicely. I am really loving the midrange in this setup, it is plentiful and always right there when needed. It makes buzzing up and down the hills here a dream.

This is a dead stop 1st-4th gear pull, with sloppy shifts and all. As you can see, there is only the slightest blip of knock, and the 550s aren't even trying. Lots of timing too so there is tons of room here!

jbrown7815

iTrader: (1)

Great thread, nice car!

underdog

iTrader: (6)

Hey Everyone!

I'm back from the dead! Or it least it would seem that way. The past weeks have been pretty exciting. The big news being this little guy showing up.



Babies are just a little demanding, so I haven't had much Miata time, but I did finally post a couple videos! They aren't earth shattering, just a little horsing around on my part. I have had zero time to dial the car in, but it's running pretty good as is. I can't wait to lean on it! Oh, and one more thing, I had an old, busted iPhone, so I stuck it under the hood near the intake and recorded some turbo sounds for my ringtone. Here 'tis if anyone is interested. Miata turbo sounds ringtone/mp3

Thanks for reading, more to come soon.

Braineack

iTrader: (62)

when will you suckers learn how to post a yt video?

levnubhin

iTrader: (30)

Beautiful little boy Tom, congrats. Is he your first? I remember when my son was that small, he'll be 4 in Oct.


Vids aren't working.
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underdog

iTrader: (6)

Thanks for fixing Brain, I appreciate it. I need to slow down over here.

underdog

iTrader: (6)

Thank you! He's our second, we have a 3 year old girl too. She's really taken to the idea of being a big sister...for now!

curly

iTrader: (25)

Holy rock solid boost Batman! And you're sourcing it from the "wrong" spot, interesting...

Braineack

iTrader: (62)

you rang?

m2cupcar

iTrader: (5)

Isn't electronic boost control wonderful?!

Braineack

iTrader: (62)

I'm a fan.