Anyone know how bad boost spikes on a k04 with a 3.5" exhaust are?

Mazdasloww3

Greenie N00B Member
Greenie Member
Dumb question, I'll be the first to admit that. Was just gonna wait and do mani/big turbo and 3.5" exhaust all at once after all supporting mods are done, but my BATs are so damn high in south Texas on a gen 1 TMIC, completely neutering my speed, so gonna go ahead and get an e30 tune for the meantime. However, if I'm gonna do that, I'd at least throw an ebay downpipe (and 3 port EBCS) on it first for those easy gainz.

I don't mind porting the IWG for giggles, ig my question is if anyone has any insight into if an e30 blend with a ported IWG on a k04 will make boost spikes manageable on a 3.5" exhaust. But as I was typing this, I figured that maybe I should just see if I can't weld a 44mm vband flange on the stock mani and weld the IWG shut on the k04. Probably a better use of my time, and I'll actually use the ewg later in my build, as opposed to some temu dp. Still interested in opinions though.
 
Just don't use dramatune and you will be fine without changing the iwg
 
It's not recommended. Get a 3" exhaust, you will be fine. They would not recommend against buying something they sell unless it's a bad idea.

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that warning is for the full exhaust, i may have misread op, are you talking about boost spikes with just a downpipe or with a downpipe and full exhaust?
 
that warning is for the full exhaust, i may have misread op, are you talking about boost spikes with just a downpipe or with a downpipe and full exhaust?
Full exhaust. Yeah 3.5" is dumb on stock turbo, I'd just rather get an exhaust I'll use for the rest of the car's build. Turbos love free flowing exhausts and I like making stuff efficient. Also just generally overthink everything for better or for worse.

Honestly though, much better and easy solution is to get a roll of ultra thin .04mm stainless. Cut a restrictor that will fit inside a vband, probably go with a 3 inch restrictor to start with, and just throw that where the dp connects to the midpipe. Can easily change restrictor size as needed. Might still port IWG for fun and see how much I can squeeze out of this k04 (Probably will lead me to testing out those $20 ebay k04 rebuild kits sooner rather than later lmao)
 
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