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Discussion Starter #1
Haven't posted here in a long long time.. But, long story short. stock internal D16z6 with DSM black tops, Walbro 255, Go Autoworks mini ram and small AiResearch turbo with some patchwork piping and a tiny FMIC was put together and tuned with ECTune back in July of 2015. The car (94 civic dx) ran great until it completely annihilated an Exedy organic disc which was replaced with a Comp stage 4 clutch. Back to business as usual.

Recently ( early February of this year ) ordered new charge piping and a much larger FMIC from Go Autoworks and as per usual everything was great. I up sized my hot side from 2.0 to 2.5 and the inter cooler was substantially bigger than the tiny one I began with. Had to reclock the turbo for the silicon elbow coming off the u pipe to connect to the turbo. Everything reinstalled without issue. T bolt clamps tight. Vac line from turbo to WG replaced so it wasn't pulled tight, turbo bolts tightened.

Went to drive the car and it drives fine,however when it gets into boost and achieves what should be peak boost at 14.7 (or whatever 1 bar is, as that's what the Tial MVS I bought was equipped with) the car violently cuts out, simultaneously goes lean, but just as soon as I let off the throttle and ease back into it it's business as usual. I'm assuming I'm hitting boost cut? I changed the vacuum source for the WG to the intake manifold and plugged the tap on the turbo and tried again and it's still cutting out at what looks like 15 or 16 PSI?

Is this a case of a failing wastegate? Or is it a symptom coming from the fact that I installed a much larger inter cooler with larger tanks, and upsized the hot side from 2.0 to 2.5 and needing a retune?

I appreciate any help or suggestions guys and gals.
 

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Sounds like boost cut. Youre probably just getting less pressure drop across the bigger intercooler.

Let me guess, the wastegate source is on the hotside (like the turbo compressor cover)?
 

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Discussion Starter #3
Correct. My tuner told me my cut was set for 16 psi. Also suggested moving the vac source to the large port on the intake manifold, so I did, but to no avail.

I did notice that the turbo seems just a bit quieter and that when it gets into boost it seems to spool harder than before, could just be my imagination though. Not sure if that's pertaining to the bigger IC or anything of that nature.
 

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Wastegate should be connected to the "cold side", after the intercooler. Ideally it should be before the throttle, but not for anything to do with overboosting.

Your setup is just working better now. Youre going to have to get a softer wastegate spring. I would rather have a softer spring and turn it up with a "ball and spring" MBC anyway. It will improve spool.
 

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Discussion Starter #7
Yeah my hot side was a patchwork mess of hose and welded up bullshittery but for the longest time it was fully functional. I'll order a weaker spring or two and swap what I have out. I'm just a little concerned because the WG has the 1 bar set of springs but it's still slamming 16 when the boost comes in all at once, is a MBC/spring change really going to correct that?

Edit -- and thanks, for the input. Both of you.
 

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It is not uncommon to spike a little bit. When I am tuning a car I always have to set boost cut a little higher than what the car is actually hitting because of spiking and changes in weather.

IIRC when running Hondata you can use a little control system (like a PI controller) for boost cut so that it can ignore small spikes and will only cut if it is legitimately overboosting.
 

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Discussion Starter #9
Cool, as I said I just find it weird because I live in Florida and we've pretty well dealt with our winter months so for it to be acting weird during warmer climate when that's what it was tuned in to begin with just feels unusual, but then again I'm no tuner. I'd love to learn though.
 

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Discussion Starter #10
Update: opened up the MVS and found two springs, grey and gold. Grey is good for 8.7 and gold for 5.8. Left the grey, verified the plunger wasn't sticking, reinstalled and buttoned everything up. Took the car for a spin and found it peaking at 10, and falling back to 9 and sustaining that. I'll deal with the MBC shortly, can't decide if I wanna just buy one or try building my own, though knowing me I'll probably just buy a TurboSmart or something like that.

Thanks again guys or girls.
 

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Civic and Accord
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Buy a solonoid and use your ems to controll boost
 

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Discussion Starter #13 (Edited)
I spoke to my tuner about letting my ECU control boost but we came to an agreement that should I ever get serious and actually build the motor to make legitimate power we'd probably delve into that then.

As for weather the car has been pretty steady at where it peaks as far as boost pressure, only now has it become an issue and the weather has been constant for the most part. It is what it is though, I have a boost controller coming and by some time tomorrow I'll have it dialed back in to where it was.
 

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Discussion Starter #14
Final update: MBC is in. 3 adjustments later and it's spot on. Seems to spool quicker, holds well, hitting at 15 and by the time I get to redline it has finally fallen to 14.

Thanks again, everyone.
 

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98 ex coupe
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Ended up going with a TurboSmart model off Amazon. Could've probably gone to Home Depot or Lowe's and bought the stuff to build one but I just wanted to get it done.
nice man! good to see you got it sorted out....I was curious to what it was after your first post! Also what part of florida you live in?
 

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Ended up going with a TurboSmart model off Amazon. Could've probably gone to Home Depot or Lowe's and bought the stuff to build one but I just wanted to get it done.

Same here, I opted for a hallman though. Solid part, but I'm switching over to an ebc next.
 
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