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Old 06-17-2008, 03:00 PM   #1
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Default Flyin' Miata Wastegate reduex

So I got my FM provided upgrade a couple days back (and have yet to send back the original wastegate provided! My bad! Soon though, just have to find it!).




The bracket is nice, nicely made! Looks strong, reasonably rigid. As to the overall design, I have to say I like it, but I'm biased: It's exactly the same position I had mine in! I spent an entire morning getting this just right in my car - using just what I happened to have laying around. So it's pretty lucky I hit on the same things they did. Of course, I had done some minor cheating, to get things just right, I stuffed a washer or two under the plates to get the angles better.

Here's their original plate supplied with a different wastegate, and my home-fabbed spacers shown side by side with theirs. These are very similar in height:


...but theirs is a bit higher. I think this is to ensure the wastegate doesn't rub on the front of the compressor. They mount the can with the tab 'downfacing', which I found hard to do - so I mounted mine 'upsidedown'. And I used nordlocks, which I just like. :-) Since the spacers were steel, I just tapped those, where FM welded nuts on (understandable when you look at the cost of construction, reliability, etc.)

Welded Nuts:


Here's my bracket, on the motor. I like to view wastegates this way (who would have thought I'd grow up to have a preference in how I view my wastegates?), as it gives you an idea for the alignment and the preload, and the angle the actuator will push at)



And the FM unit:



The cans (for some reason, the first time around, I compared every number but the right one) are the same as best I can tell. Start moving at 4.5 psi, and seem to be at full travel by ~13-14.

Full extension:

It looks like the brackets are in just a slightly different spot, but remember I spaced mine out with two washers.

Here's the two wastegates, you can see the part number is the same. It's the one that originally comes with the GT28, so it's a good choice. :-)

The one with the hose on is the one that originally came from FM with the FM-II on the old style (good riddance to that piping!) intercooler kit.

One last pic of the bracket:


Closing thoughts:
If you have a very high flow set up (I've got some mid-range headwork, 1/2 mm bigger valves, FM downpipe to a very smooth 3" exhaust, and the new FM intake) you'll probably get quite a bit more boost creep than you can live with without advanced engine management (Hydra, Megasquirt, etc). I'm assuming this since I had my gate in the same place, and tested it. With lots of extra timing advance, it's less of an issue, and with lots of turbo porting to ensure good flow to the wastegate, that helps.

For folks who's only sin is living at sea level - without pushing the capabilities of the wastegate with all the extra flow, this kit probably works well. And I doubt it has the insane resonance (Jeremy at FM noticed it too on the old bracket, though not as extreme as my +50 lbs modified one) so it should last a long time. The misallignment of it being too high (the other dimension is taken care of by the slotted holes, very nice!) I guess it ok, but if I could have found a way, I would have made the wastegate sit lower. It grabs the pin in a funny way:





This makes the e-clip hard to get on (livable) but I worry how freely it will travel. In a couple hand tests, it seemed ok, and the car has been driving fine with it. Overall, I save weight, and it gave me a chance to check out my new locknuts/studs, and do some other maintenance while I was in there. :-)

The only issue that really remains is that one of the bolts that holds it on is pretty loose - I've used that hole so much all the threads must have left. I still haven't learned how to tighten a nut.

I don't know why the almost-perfect bracket doesn't have the wastegate 3/8th inch lower, but other than that I would say it's a fine piece, and again, Kudos to FM for not only developing a replacement piece, but providing it free of charge to the folks who had already bought the inferior version.

My only remaining (very minor!) complaint is they were never clear - though I asked a few times - on what parts they wanted back. I guess I'll just send them the old can, and if they want the bracket too, they can tell me - though I've drilled through mine to make a place to hook a spring for some other thing... :-)

Last edited by AbeFM; 06-17-2008 at 03:02 PM. Reason: pictures malformatted
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Old 06-18-2008, 12:13 PM   #2
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We're interested in the wastegate actuator, although that's primarily for people with the newer kits that came with a different wastegate.

Since your car was upgraded and already had the correct actuator, I wouldn't expect a big difference in behavior with the new setup.
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Old 06-18-2008, 01:47 PM   #3
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Awesome, I'll drop it in the mail in the next day or two.

Was there a conscious choice to have the can sit so high, or was it just to be sure not to contact the turbo? Maybe there's something to approaching the actuator arm at an angle I'm not privy to. :-)
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Old 06-19-2008, 03:55 PM   #4
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I'm actually not sure. I wasn't involved in the design of the part, so I don't know what all the design considerations were.
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