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Turbo for the 2.3 6i

107121 Views 163 Replies 64 Participants Last post by  RiveraJ
This will be an evolving thread, but should provide enough info that we won't have a new thread every other day asking the same questions. Please bare in mind that the info provided is based solely on my experience and opinion. Please take the info i have and use it as you will, discuss the project with your local shop/tuner/dad/brother and move forward from there. Anyone with more info please feel free to give input, but i will be cleaning this thread up as it goes, so please don't bitch.

Q: What are my options for turbo'ing my 6i?

A: The options vary currenlty. there are 5 standard answers, most can be googled for more info
1) ]HiBoost (out of business, but used kits floating around)
2) F2 (never officially release, check with GP-Werks for more info)
3) HASS (via (not produced, but at least 2 kits floating around)
4) built using Mazdaspeed6 parts
5) depending on where you are, a TRUST (Greddy) kit is available, though tuning has yet to work in the states, as well as fitment issues with LHD models.

Q: Do I need to build the engine? what boost can i run "safely"?

A: The stock block has been pretty good on about 8psi on pump gas. Anything more than that the bottom end should be addressed. solid tuning and race fuel can up that #, but people have popped engines above 8psi.

Q: What about the tranny, i have an ____ (insert MTX or ATX)?

A: both tansmissions will be fine.
1- The stock MTX has a tendancy to sheer 3rd gear at times (no specific power level, just some last and others don't)
2- Both 4 & 5spd ATX trans also work, though it's recommend to run 6psi on these setups. also, an additional trans cooler is essential as well for the atx.

Q: Can i make my own, i found a good kit on ebay?

A: sure, have fun, don't cry when it doesn't work right and cost more in the long run!

Q: How much can i expect to pay?

A: Quick answer is have $5k ready to spend, or don't think about it. Now, it depends on the kit obviously. F2's stage1 will be the lowest price KIT, and HASS ranges up to $4300 i believe. You can make your own Mazdaspeed'ish setup, but it is not a kit, so prices will vary and you'll need to find your own tuning solution. The install is amazingly easy in these cars, the install would range in the 5-8 hour range if you are looking at a shop. Most KITS will come with a tune to get you started, though it's recommended to to dyno tune your specific car, which is roughly a 2 hour job, though doesn't really need to be done ASAP.

Q: What else do i need to buy?

A: If it's a true kit, then nothing! There are items to make it better, make it last long and obviously make more power....but they aren't needed. Things i would recommend you have on our short list however, as they will aid with tuning and safety.
1- a WIDEBAND (no, the narrowband you saw on ebay won't work) Air/Fuel gauge, this is a must for tuning
2- spark plugs (i REALLY like the Autolite 103's, especially in the beginning while tuning. They are UBER cheap, and work well, easy to gap also)
.....that's it, for the long list i'd add:
3- oil temp OR pressure gauge (dont' see the need for both, and no your stock gauge doesn't do anything. this is only to see problems sooner, nothing else)
4- boost controller (DO NOT ADJUST BOOST!!) A boost controller will aid in how the boost comes on and levels off, feels much better. i suggest a manual controller in the engine bay that you CAN'T touch while driving)

.....There are other things, but they are not turbo related, they are performance related. (things like limited slips, clutch/fly, better rubber). you DO NOT need a turbo timer if you have any common sense, you can, but you are just spending money.

This is all the basic info on the setups that i could think of. For the most part, an 8psi intercooled kit on a STOCK 6i MTX in the 225whp range, the ATX (6psi) at just over 200whp. Power will be increased with an exhaust, which most have anyhow, but it's not needed to enjoy boosting.

notes for the ATX guys:

'03-'05 6i's with the 4spd have an off the shelf option to upgrade both their valvebodies and torque converter from, or whole tranny if you'd like. The valvbodies help out an amazing amount, and allow for a bit more boost if you want, the converter allows for a higher stall speed which is nice if you powerbrake often (the strip) and they can also remove the lock-up setup which can be a bitch when having fun on highway cruising.

'05+ 5spd ATX's have faster/tighter shifting out of the box, so that is a nice start. If valvebodies are something you want (as they can be improved quite a bit), has experience with them, though you need to remove yours and send it to them for the work.

Both models- please take a minute to understand how your ATX works, and then understand why i say you should always let your foot off the gas between WOT shifts. It is not something that will brake the tranny in one time, but please understand it's not recommended as the boost is still being applied while the tranny is trying to shift. Also, for the same reason, if you are cruising on the hwy while the converter is in lockup, DO NOT just slam it to the floor, it's not good for it either, a quick blip or downshift will safe a lot of trouble.

Now, i know of roughly 6 turbo'd 6i's that are (or have been) daily drivable, there are currently 4 on this forum actively i believe (as of 6/09). I would imagine all would attest that it's a friggin blast to drive, and the smile doesn't leave your face! The car is still pretty light at just over 3k, so the addition of 80-90WHP (about 60%) makes a huge difference in feel. But keep in mind that it costs roughly $5k on the low side for the setup, which is anywhere from 25-50% of what the car is worth, premium gas is required now, and it's hard to go back to stock if you think it's temporary. In the 4 years i've been turbo'd and talking to people about it, i've found that if your plan is more than 6 months (it's more like 3-4) out, then you won't get it. If you have 90% of the money in hand and are serious, go for it, but if not, there's not need for a billion questions that don't go anywhere, please just read what's on here already and enjoy the dream (it's cheaper!)

This link will always show you all the current topics for turbo's on the 6i's:

Turbo threads

here's a few vids that have been around forever, but if you are new you might like them.

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You don't need to route the the BPV/BOV back to the intake manifold. People typically do this on draw thru MAF setups where venting to atmosphere would cause a temporary rich condition after a shift because metered air is vented off and lost.

There are two ways to fix this:

1. Run a blow thru MAF setup and have the BOV/BPV plumbed prior to MAF so no metered air is lost. Blowthru setups are far more accurate in terms of air volume and air temperature metering accuracy on a boosted app. Some people go draw thru simply because they are in fear of saturating the MAF (flowing more than the MAF can meter). But blowthru is the best in terms of accuracy. There are also ways to keep the MAF from saturating and increasing range.

2. Tuning TIP-IN enrichment

If I were you I would not waste time on a K04 or the stock speed manifold. Get an aftermarket speed manifold with a T3 flange. Why? Because it opens up numerous turbo options. Just my educated opinion

Have you tuned draw through vs blow through on the stock ECU? I'd suggest actually doing it before recommending lol, I've done both setups.
Draw through absolutely requires it be routed back into the intake if you want stock like drivability. It will run rich / bog/ even stall at times on shifts if you don't, and especially if you go into boost then go out of gear and down to idle you'll stall.

and with blow through MAF placement, MAF housing size, etc all come into play, and it just won't run right in boost unless you're very, very meticulous with MAF placement, and how much straight section of piping there is before the maf. You'll get MAF range /performance CEL's and limp mode often. I know, I've done it on my personal car trying with a few different MAF housings on stock ECU. Draw through ended up being the easier, better performing option.

And with the MAF through as soon as you hit 4.9 volts on the MAF the ECU kills power and you limp until you shut it off and back on, which is much easier to do on blow-through.

Agreed the K04 isn't the nicest option, but it is cheap, and can flow more than enough for someone who doesn't have a built engine.
If that IS a show stopper, has anyone ever added a port somehow to the regular intake manifold to function in this manner? Drilling and epoxying a port somehow to a composite/plastic manifold gives me the heebie jeebies. We've considered getting a couple of throttle body spacers, welding them together, drilling and welding a port there, but now we're moving things pretty far out of whack and are unsure if we'll run into other fitment problems at that point.

Appreciate any advice or thoughts,

Also- the bov recirculates back into the intake after the MAF, not the intake manifold :)
I attached a picture, not the best since it's not a mazda, but it does have a MAF and recirculating BOV. see how the BOV has a pipe going from the BOV to the intake behind the MAF? just like that.


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There is no tables in mazdaedit that will make running a VTA bov possible without rich afr on shift / throttle let off. I have defined every single map on these denso roms for 2.0L and 2.3L, and mitsu 2.5L. Making the tables as in low level program / coding them would be so much work it's not worth it for a single ROM.
I understand you tune various platforms, I'm just saying we have tried and tested specifically these ECU's to ensure what works best, and Draw through is great, and would work perfect as a hybrid SD/MAF, but MAF alone it can cause some issues.
It's much easier, simpler, to just do draw through with recirc bov.

Deleted other posts because my phone multiposted sorry
Must get a lot of cali Mazda 6 cars then....because those are the only 2.3L Mazda 6's that came with Denso ECU's.

I don't have time to argue with you. OP, I'm around if you need me.
Plenty of non Cali mazda 6's had Denso ECU's lol they are just low emissions ECU.. uncluding the mazda 6 MZR-CD Diesel

Regardless the ROM data is the same
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