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Mazda Engine Performance \  after some input on my turbo build

after some input on my turbo build

Mazda Engine Performance Mazda Engine Mazda Tech
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daeman   +1y
Hi folks,
I'm looking at starting my turbo build over the next few weeks and before I actually get it underway, I'd like to get a bit of input before I fully commit to it.
Basically my drive line is all pretty tired at nearly 400,00km , so the time has come to start replacing it all.
I've got a spare gearbox as well as a rebuilt 626rwd gearbox which I'll be frankenstining to get some better ratios. Also got a LSD diff with axles and all new u joints as well as a new center bearing.
That's the back half of the drive train sorted, with the exception of a new clutch, but its on the list.

Here's where you guys come in,
I have a bunch of stuff I've been slowly collecting and now I need to decide what exactly I'm going to do with it.
I've got an old 1st gen mx6 fe turbo engine, I've also got a spare f2 8 valve carbed motor from my old truck. Both motors were runners prior to storage.
I'm looking at stripping them both, hoping to use the turbo block and head, as well as pistons if the cylinders don't need to rebored.
I'd like to use the f2 crank and rods so I can get the exra torque and displacement that comes with them ( yes, I know it won't be much of either, but every little bit helps.)
I've got the fe turbo exhaust manifold and turbo, but the turbo would need an overhaul and is to damn small anyway. I have a Toyota spec ct26 garret turbo which needs work but is common so cheap to repair. Otherwise I have a fairly fresh China spec t28. I'd be making an adapter elbow to allow me to spin the turbo so the exhaust side is to the rear, and also to give me better clearence for the ac and power steering along with serving as a flange adapter. Thoughts on which turbo please?
For the inlet, I have the tbi manifold from the mx6, which is pretty ordinary. Otherwise, I have a rwd 929 inlet manifold, its multipoint, the throttle body faces the right way and it suits the 8 valve heads I have. It'll need a bigger throttle body, which is about 40mm at the moment, but otherwise it looks like the neatest and best option.
I have an ems stinger stand alone ECU, walbro 255 fuel pump, adjustable fpr, but still need to select injectors.
For ignition, I have an electronic dizzy from the f2, but would prefer to run distributorless ignition and set up a trigger and waste spark system using a Mitsubishi qaud coil pack that I have.

Whilst I've got a fair idea of what I'm going to do, its always good to hear other peoples perspective and hints or where they've gone wrong.

I want to keep it streetable, daily drivable and flat out performance isn't what I'm after here.
I don't want to make massive figures, but I think I should be able to get a reliable 150+ HP at the treads.
Is it doable with what I have, and again, any general thought would be great.
Post was last edited on Oct 29, 2014 06:10. This post has been edited 1 times.
dealwithit   +1y
sounds like your going in the right directions but i dont see how the longer stroke crank and rods are going to work in the shorter FE block? maybe if you sourced out some shorter rods that would work, but you could just go with the f2 block and save all the trouble, or just stay with the FE setup and enjoy a few extra rpms up top. now can you direct fire your coil pack from the ems you have, or would you need a ford/mazda edis system that just requires a small signal from your ems to run all the plugs/coils/ignitors? you could run that, and just use the lower half of your electronic distributor for an ems signal (or mount a crank signal ring if you have the means to). oh deff go with the multiport intake, with a normal set of injectors, then if you need bigger its a simple change out and retune.
daeman   +1y
Hi dealwithit,
Thanks, I have a fair idea of how I'm going about things, but figured I'd use this thread as a sounding board to bounce ideas of before I jump in feet first.
I appreciate the heads up on the possible deck height issue, as I figured the f2 would utalise the same block as the fe, just a different rotating assembly like most other stroker engines.
Ultimately if there is a deck height issue I'll probably use the f2 bottom end, only really wanted to use the fe-t bottom end due to everything already being drilled and tapped for turbo. No biggie either way.
I'm going to look at whether I can run a cas sensor under the timing belt cover or something as I'd like to keep the engine looking neat as possible, that said, if its to much work, I'll probably do like you said and run the f2 dizzy as a trigger only and find or fabricate a flat cap for it to make it look cleaner.
Multipoint is certainly the preferred manifold, I'll just have to make sure it can accommodate a bigger throttle body, looks like an sr20 tb has the same bolt spacing so may just need to bore out the mounting face of the plenum to suit.

There's so many little things I'll need to take care of, but I'll start throwing those up as I come to them.
Cheers.
Damo
mazdatweaker_2   +1y


The FE block is about a 1/2" shorter that the F2 block so you cannot just swap a F2 crank into an FE.
daeman   +1y
Thanks, saves me measuring it this arvo. Looks like I'll be using the f2 bottom end with the fe-t pistons, providing the bores in the f2 measure up right for them. I'll just have to do a couple of mods on the f2 block.

otherwise it'll be a a new set of f2t pistons. I'd prefer the original Mazda pistons both for them being OEM and to help keep costs down but I'll have to wait and see.

Cheers for the input so far guys.
dealwithit   +1y
the problem with f2t pistons (at least in north america) is they came under a 12v head, so the valve notches will be in the wrong places, at least on the intake side. the FET pistons i believe only came under an 8v head, so those would be the ones you want, might even be lucky enough that your current ones will go into the f2 block, as in it wont be to badly worn when you get into it
daeman   +1y
Pretty sure the 8 and 12 valve pistons have the same notching. Reason being the 8 valve heads have Siamese ports and would have required 2 different piston notch configurations for the same engine which wouldn't be economical from a manufacturing stand point so they just cut 2 inlet valve reliefs that way the same piston can be used in all cylinders.
I could be totally wrong of course lol, but pretty sure I've also read that on Mazda trucking and mx6.
From what I've seen of peoples rebuilds on the f series engines the block casting is great quality and doesn't wear much, sobfingers crossed I get lucky and can use the turbo pistons I already have...
daeman   +1y
Ok, so I'm spending plenty of time reading and researching.
Looks like fet pistons are a no go in the f2, fe piston crown height vs f2 is about 2mm shorter.. Making for a ridiculously low compression ratio.
That said, standard n/a pistons have copped boost in plenty of applications and provided the engine is well tuned have stood up well.
8.6:1 would actually make for quite a turbo friendly ratio so will probably just run an n/a f2 bottom end.
So its looking more and more like the only bits of the fet that will get used are the exhaust manifold and possibly the head and maybe the camshaft (modified)
I'll keep reading and searching as I start tearing down and go from there.
160-180 rwhp is starting to look pretty comfortable if I do this right.
dealwithit   +1y
i wonder if thats because the factory CR in the turbo motors is 7.8:1, which is crazy low. the factory 8.8 or 8.6 CR of the F2 should handle boost pretty well, i think youve got a solid plan. you should be able to hit 200 no problem with good tuning and plenty of airflow
befarrer   +1y
As for 8V vs 12V pistons, I think, by looking at 8V pistons only, that you could probably get away with using 8V pistons in a 12V motor, but not use 12V pistons in an 8V motor. Reason being that the 8V has a much larger intake valve than a single intake valve of a 12V motor, and if you look at the valve reliefs in the 8V piston, they overlap, I would assume the 12V pistons have a smaller cutout to clear the smaller valves. But I have not seen a 12V piston.