threads
Page 2 of 3
Mazda Engine Performance \  new here with a quick question about boost

new here with a quick question about boost

Mazda Engine Performance Mazda Engine Mazda Tech
views 1823
replies 20
following 3
 
anguswilly   +1y
These truck are mass-air, so it's really easy - just like any boost kits for other mass air cars - you can use the FMU and you're good, I am running a 10:1 ratio and I get almost perfect AFR's
sinix3   +1y
Bare with me what's an fmu?

So with a mass air the ecu will adjust without a tune??
anguswilly   +1y
That is correct (to a point), the air meter can add fuel up to it's limit, the issue is that the ECU is tuned to provide 13-14:1 AFR and you'll need 11:1 - as long as you don't flow enough air to max out the mass air meter, then you are fine, with 6-7psi, I measured mine and it's still below 5v so it should be fine.

The FMU is a rising rate fuel reg. It adds fuel pressure as boost comes in, many many aftermarket turbo and SC kits use them - yeah they have a bad rep, but that is mostly from "haters" who like to make their life hard.
sinix3   +1y
So with a fmu and a better fuel pump I could run like 5 psi?
anguswilly   +1y
You can run more than that - I ran 15psi on my old truck before I ran into lean AFR's

Higher boost does have more problems though, I would stay under 8psi to avoid tuning and engine trouble.

As I said, these motors came with turbos from factory and they also came diesel with the same block - the blocks are bulletproof, the probe / mx-6 guys have done close to 500hp on them.
sinix3   +1y
So the only problem would be the pistons if it ran to lean they could like melt. This is awesome I'm going to try and fabricate a intake for my eaton m90 and then a pulley would be easy

Should I run bigger injectors or would that screw everything up?
anguswilly   +1y
This is why you use a wideband AFR gauge - to avoid lean AFR's.

Now I don't want to scare you off of doing this if you really have the means to do it ( I do think it would be cool to try) but I sense maybe you have not fully planned it - I do have many years of experience in doing turbo and SC setups and have learned the hard way.

If you have done SC setups then you know it is a little more (a lot more) involved than a simple pulley, you are going to have to fabricate:

- Very strong mounts for the S/C unit.

- A crank pulley for the SC - this will be tricky because the size dictates the boost level you will get, this will be custom machined and get expensive quick if you need to keep making them by trial and error to get the right boost.

- A bracket to run at least one idler and a tensioner - again, tricky because if you don't do it right, you will not be able to find a belt the right length and even if you do the belt could be crazy expensive (some belts, even going one size up or down and the cost can be insane)

- The Flange to bolt up the SC to the manifold

- The pipe with a flange to go to between the SC and the Throttle body

- Some kind of intake plumbing to go from TB to AFM - and then the filter

- Some type of bypass valve - if the SC does not have it built in.

- You'll still need a fuel system of some type.

Also to keep in mind is that the M90 is made for a big engine - This could lead to issues, it'll either flow too much or it'll rob too much from the crank by the time it makes power.

Also, if your SC needs a rebuild or replacement, they can be expensive - and they do fail - lots.

Which leads me to another point - I almost never like SC's on small displacement engines - because they
rob so much power at low RPM before they make power - a turbo is using the spent exhaust gas and the drag on the motor is minimal comparably.

NOW - if you go turbo - you need: (minimally)

- A probe / mx-6 manifold and turbo - bolt it right up after a couple quick mods (like bend oil dipstick tube)

- Get a muffler shop to bend you a simple pipe to connect the turbo to the TB and the turbo inlet to the AFM (maybe $80)

- Get a muffler shop to make a down pipe to connect the exhaust ( maybe $50)

- You could also just buy either pre bent exhaust pipe u-bends, chop them up and connect with 2" rad hose (I built tons of setups like that when I had no money and they worked great)

- You can also buy the silicone bends from ebay and use straight pipe in between.

** if you use the last two, you'll still need somebody to weld the down pipe.

- Connect the oil inlet (just screw it into the block, the hole is there) and drain line ( you can drill the block or tap the pan without taking it off like vortech does)

At this point you'll be boosted for a few hundred bucks tops and you can then just add your fuel pump and FMU which you'd also need with your SC.

If you are dead set on the SC - I hope I helped shed some light in what you'll need.
anguswilly   +1y
LOL - I just realized you are in mission, maybe you should drop by I'm in poco.

You can look at my truck, I have it set up about like I described with no intercooler - the only difference is I did it so it would look pretty with expensive parts
sinix3   +1y
The main reason I'm interested in a sc is because I have one and I have a place that is willing to let me use material and a tig welder for what ever I need. iWork during the week but some times I have days off so I'll try and come out.
anguswilly   +1y
LOL - a tig welder and some material?

You're gonna need a CNC machine and a machinist and probably $2000 in miscellaneous parts and pieces to get that thing to work