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Old 03-20-2010, 08:05 AM   #1
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Default Running a turbomiata without...the boost.

Hey guys. I'm in sort of a dilemma here. I'm moving to another city for a few months and my mspnp isn't back from repairs yet and won't be for atleast until weeks after I move.

Over the winter months I sold off my turbo band-aids (fmu, e-manage) and upgraded to larger 550cc injectors. Would there be any problems if I wired my internally gated T28 (GT2560RS) open and jam my stock ecu back in the vehicle? I'll have to throw in my original injectors of course.

I tried searching it up but I only came across one posting from a user that stated he did the above and it still boosted to 2-3psi~ and a couple others said that they ran at ~0 vacuum. I'd take off the turbo parts but I don't have any NA OEM parts to replace it with.

Is there something I'm not taking into account for or I should be good to go? Even if its a few pounds I should be ok?
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Old 03-20-2010, 10:25 AM   #2
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You might consider renting a truck to tow the Miata with if a solution can't be found.
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Old 03-20-2010, 11:00 AM   #3
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There was someone on here a while ago that took the wheels out of his turbo. He made a block off plate such that the turbine housing was still in place, but he could run NA. Wouldn't be a bad option if this situation will come up again.
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Old 03-20-2010, 11:14 AM   #4
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your still gonna build a pound or two (if that) but nothing that would be a problem. ppl have been wiring/removing wgs on turbo appications to temporarily kill boost for a long time without any probs so you should be completely fine. its just gonna be less fun to drive it and it'll sound a little different haha
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Old 03-20-2010, 11:46 AM   #5
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wire the wastegate open and stay out of the throttle
even at atmo manifold pressure the turbo is flowing more air than if the car were n/a, so you have to be really careful.
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Old 03-20-2010, 11:58 AM   #6
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Or just hack job some crap plumbing that secures your AFM to your TB and put some mesh screen over your turbo, with the WG wired open. It will sound cool, but build 0 boost.
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Old 03-20-2010, 12:20 PM   #7
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buy a cheap FMU.
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Old 03-20-2010, 12:23 PM   #8
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Quote:
Originally Posted by Sparetire View Post
Or just hack job some crap plumbing that secures your AFM to your TB and put some mesh screen over your turbo, with the WG wired open. It will sound cool, but build 0 boost.
yah, but with no backpressure on the compressor you could overspin the turbo, and damage it.
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Old 03-20-2010, 02:14 PM   #9
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I had upwards of 5-6 psi way up at redline with an open waste gate. This was MS with 1.8 injectors, so I was safe. Find someone who will loan you a MS for $20-40. Cheaper than blowing up your engine or renting a trailer.
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Old 03-20-2010, 02:24 PM   #10
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Just wondering now why some guys said they built boost, some didn't. Regardless, I'll probably pick up a cheap fmu or.. Pay my friend to store the car and take.. The transit. Most of my friends drives hondas or subarus. They never even heard of megasquirt.
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Old 03-20-2010, 02:27 PM   #11
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It depends a great deal on the WG itself, th specs of the turbo, and tuning. If you have a little internal WG and a T25 or 2554 and all, then you will probably spool up pretty well. if you have big EWG and a 2860 or 3071 on a .86 ar or greater turbine housing then probably not.
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Old 03-20-2010, 02:28 PM   #12
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yah, but with no backpressure on the compressor you could overspin the turbo, and damage it.
Good point. It has almost no resistance.
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Old 03-20-2010, 02:29 PM   #13
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FYI:

I am running my turbo 1.8 right now with the wastegate arm disconnected (wastegate flap open) and stock injectors and ecu to get thru emissions with obd2.

I havent really reved the crap out of it or floored it but just driving around it wont build ANY boost. even up hills.

Turbo is sr20det t25 with stock internal wastegate. its $100 to rebuild so im not gunna cry if i do over spin it and damage the turbo.
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Old 03-20-2010, 06:16 PM   #14
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I ran my 97 without anything for about 8-10 or months...I just didn't boost. I did this with stock injectors, then 305's and a timing box, then with 305's and no timing box. Just don't get on it and you will be fine.
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Old 03-20-2010, 06:32 PM   #15
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Wire the wastegate open and don't drive like Brian spilner.
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Old 03-20-2010, 08:07 PM   #16
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i have mine setup like this at the moment just to get it running again. it will work.

im not sure why, but mine is running super rich.
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Old 03-20-2010, 08:24 PM   #17
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Quote:
Originally Posted by shlammed View Post
i have mine setup like this at the moment just to get it running again. it will work.

im not sure why, but mine is running super rich.
...because there is no boost, there is more fuel than air being mixed in the cylinders.... better watch that.


As for the OPs question, I blew my bearings up in my T2, so I planned on ordering a replacement/upgraded T25 from here. While I was waiting to recieve said turbo, I dont have a stock manifold anymore, nor do I want to ruin the turbo even further, I didnt want to park the car since it is MY dd, and my wife would throw a fit if I stole her ride... so I just disconnected the wastegate arm and wired it open for a two months until my replacement came. No problems, just watch that lead foot.
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Old 03-20-2010, 10:06 PM   #18
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I think the issue is, the MAF senses more air (as it's being sucked from the turbo), but not providing more than 100 Kilopascals...and the stock ECU is like, "WTF, MORE AIR???" So it holds the injectors open longer, thus causing the richness...
Dude just disconnect the wastegate actuator from the gate and wire the gate open...do you really need a picture??? I can provide cause I'm nice like that, but if you say Harley's rule, I"ll explain to you why you suck dicks for taco money. But seriously, I'll point you in the right direction, for I am the shepard.....
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Old 03-20-2010, 10:58 PM   #19
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If you're still worried about gaining boost with the WG wired open, couldn't you just take the BOV off and make a huge hole?
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Old 03-20-2010, 11:56 PM   #20
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Have you considered disconnecting the compressor outlet of the turbo to the intercooler piping???
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