Turbocharged, efi MG MIDGET. VROOM, whoosh, psssss

[lesingepsycho]

Just finished up the turbo install on the Midget. Test drove it and, although the Megasquirt is still tuning itself, it is definitely SWEET and workin! :banana:

I went ahead and paid for the registered versions of TunerStudio and MegaLogViewer which incorporate a self-tuning feature. It's all based on algorithms and formulae of which I have no particular knowledge but I know that the more I drive it, the better it will tune itself!! :thumbsup:

Just running 4psi right now but I'm already thinking about bumping that up considerably. Good thing it's raining today or else I might end up with a broken axle/blown hub!

Ok, a little lunch and then some more driving/self-tuning. :laugh:


JACK

 

[mightymidget]

carnage trail begins

 

[Guest]

Wait a minute, I thought you sold it.

Are you you, or are you someone else?

Are you sure?

 

[Trevor Jessie]

He was trying to sell it, but had no bites. So he finished the turbo install to make it more appealing.

 

[regularman]

Show me a picture of what it looks like under that hood :laugh: I got me a 1.8 turbo off a Subaru and keep thinking about it.

 

[lesingepsycho]

TrevorJesse's got it right. Tried to sell but no bites. Everyone looked at it as too much of a project. I had to bite the bullet and install the turbo myself so that hopefully I CAN get it sold.

Here's the latest pic under the hood although I have already changed a few things.

JACK

 

[Guest]

How much you need to get for it?

 

[lesingepsycho]

Easy, short answer. $3500.

However, I've got well over $10k into it with receipts and documentation to prove it so if I have to take $3500, I just might cry. But at this point, it needs to be gone so, on the other hand, even $3500 and out the door would be somewhat of a relief.

JACK

 

[Guest]

Man that's way to low. Sure you can't keep it? I hate to see you sell it.

 

[Morris]

Way to go Jack... I am very impressed by you!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Just running 4psi right now but I'm already thinking about bumping that up considerably.[/QUOTE]

Man... if you still wan to sell it, don't push it much past 5psi. That will be enough to impress a potential buyer, but not enough to blow anything up. Let the guy who buys it have fun pushing it to 9psi and blowing the pistons out the bottom of the pan.

 

[lesingepsycho]

Thanks Morris. I had considered that. I would add that I chose the low compression pistons (8.5:1 compression) and a turbo-specific cam so that I could run higher boost and I think I can run 9-10psi boost without hurting it and I'm even fairly confident it could take even more. I've seen some guys on the inter-webs running 20-25+ psi. on A-Series engines. But as you say, I'll let the guy who buys it take it to 20psi+

After about 9 or 10psi you have to start thinking real hard about an intercooler anyways and I don't want to go that far. Again, that's for the next guy.

JACK

 

[Morris]

Do you have an EGT? I would be scared to do much turbo tuning without one. I am sure you know this, but just in case... after you get to certain amount of boost, your O2 sensor feedback becomes irrelevant. Under high boost, you inject extra fuel as a coolant. You might guess that a 10:1 AFR is enough to get the job done... but you would only be guessing. An EGT is the only way to be sure you are getting enough gas to cool the cylinder under high boost. A lean burn will melt a cylinder surprisingly quickly. And the higher the boost, the margin of error becomes exponentially thinner.

Again, you probably know all this and much more... but I would feel bad if I let a brother melt down his freshly rebuilt engine without sayin' nuthin.

 

[lesingepsycho]

You're absolutely right Morris. That's a great point. My exhaust has a bung built in for running an EGT but I have it plugged right now. When I was planning on keeping the car, I was definitely going to use an EGT but for selling, that's just another $160 that I would never see again.

On the other hand, the standard MG Metro Turbo had a built in boost controller that took it to 7psi stock, on a carburetor, with no other special parts, gauges or any particular compensation devices as far as I know. It simply used a vacuum-boost referenced/regulated jet in the carb to control mixture.

But OK. I concede to your point. :thumbsup: For the sake of playing it safe I'll just stick to the lower boost that I'm getting now. The worst thing that could happen now would be some sort, any sort, of damage.

JACK

 

[Guest]

Go ahead, fiddle with it; you'll be keeping it a ~long~ time!!!!

 

[Morris]

I thought the stock Metro tapped out at 5 psi. That was why I was freaking out on 9psi. Way back in the days when I was messing with turboed cars, 5-7psi was the safe range, and anything above that was the danger zone where you had to use science and stuff to keep from blowing your car up. But that was a long time ago, and maybe I need to get with the times.

 

[lesingepsycho]

Yeah, so the stock Metro Turbo ran a compression ratio of 9.4:1 so I'm well under that. Not sure of the cam profile or how it compares to mine, although I suppose I could/should find out. Also, my sources tell me that the 9.4:1 comp at 7psi is starting to push the detonation threshold and anything above 7psi on a stock Metro Metro motor should have an intercooler.

Anyhow, the Metro Turbo had a wastegate actuator that is fixed at 4psi. However, it was then routed to an ECU/electronic boost controller that bled off the signal to the wastegate actuator to allow the turbo to go up to 7psi under certain conditions. I'm not really sure what the boost controller referenced, whether it was TPS, manifold, rpm..? All of the above? I have the Haynes for the Metro Turbo so I could go find that out too but all I know is that everybody on the "Turbo-Mini Forum" says that it was a garbage design and the first thing to do is trash the stock ECU/boost controller setup and get a bypass style manual bleed valve.

Again, if I were keeping this car, I would think really hard about getting a high tech elec. boost controller and defintely add an intercooler at some point. Plus...plus...plus... :laugh:

You get the picture!

JACK

 

[Guest]

at some point. Plus...plus...plus... :laugh:


JACK

fiddle factor...

 

[twas_brillig]

Morris & Jack: you're a couple of the reasons why it's worthwhile signing onto this site! Jack: when you're bored, how 'bout summarizing what all you've done to your Midget? I presume it's a 1275, and I've got a beautifully restored and painted BE body tub sitting in the garage and a partially assembled 1275 with a 45 DCOE and Datsun 5 speed and Rivergate kit that I hallucinate about converting to Megasquirt.....
Any idea what hp you're producing with your combination of engine/turbo?
Doug

 

[lesingepsycho]

Sure thing Doug.

It started as a 1275 block. Bored to 1293cc. New AE21251 pistons. Reconditioned crank. All new rings and bearings. Spridget-mania turbo camshaft made by Elgin Racing Cams. Lightened cam gear. New double roller chain and crank sprocket. Turbo high flow oil pump. Early style crank damper with 36-1 trigger wheel attached. Marelli Magnetti crank trigger pickup. Reconditioned cylinder head; new seats, valves, seals, springs, retainers. Chilled iron lifters with additional drain back. Oil cooler and remote oil filter.

That's pretty much the engine build. Intake is through the MG Metro Turbo SU- HIF44 carburetor converted to a throttle body with a kit from Rick Patton. Intake manifold is stock Metro Turbo. Exhaust is Metro Turbo manifold to a sort of homemade "S-pipe" up to the turbo that sits where the battery/heater would be. Turbo is stock Met-Turbo Garrett/Airesearch T-3 with a .25A/R turbine wheel and .45A/R compressor wheel. Exhaust exits through a Stainless Steel downpipe by ATPturbo for a Volkswagen 8v, Mk2,3, or 4 chassis with built in O2, EGT bungs and flex pipe. Compressor side wraps around the front and enters the carb through a homemade turbo plenum that incorporates a Greddy TypeRS Blow Off Valve.

Fuel and spark control are through the Megasquirt II V3.0 It handles the Ford EDIS-4 for distributorless ignition and 12x12 ignition map control. It also takes a signal from an Innovate LC-1 Wideband O2 sensor and controller. The MSII fires the GM 44lb. TBI injector in the Patton Machine throttle body adapter. Fuel is picked up from a 17Gal. RCI alum fuel cell. The injector is fed from a Carter elec. fuel pump built for carb-TBI conversions. Pressure is then handled by an Aeromotive rising-rate fuel pressure regulator. I bought the registered versions of TunerStudio and MegaLogViewer for real-time, on-the-fly auto-tuning features. Electric fan is also controlled by Megasquirt with a 170*on and 160*off points.

All the power heads down the train through a reconditioned flywheel, Datsun clutch package and b210 5-speed with Morriservice kit. 3.90 rear and big sticky tires. My biggest fear now is the weak points, ie. the axle and spoke wheel hubs. That can be added to the list of "if I were keeping this car" I would change the suspension <span style="font-style: italic"><span style="font-weight: bold">back</span></span> yes back :smirk: to bolt on wheels and a set of Minilites.

I hope that about covers it. I have to run to work now anyways. :wink:

JACK

 

[JPSmit]