diy 1.6 turbo questions
 

i am thinking about boosting my miata to get a little more power out of it. i a;ready have a fmu, 255hp fuel pump and a 6 puc clutch. i was going to just get the manifold, downpipe, and bov off of ebay. a friend of mine has a stock 1g mx6 front mount i am going to get and i was going to use a 14b or t25 from a DSM. retard the base timing to 6 deg and thats it. and i have a 12:1 disk in the fmu now, but looks like everyone runs a 8:1, so i will need to get another disk.

i will probaly upgrade later on, but just want a simple, basic setup for now. i have megasquirt on my probe, so i will probally just build another one for the miata and get bigger injectors and raise the boost later on.

does it sound like i have everything planed out ok so far?

manifold, downpipe, and bov off of ebay... You need to be more specific. There is a lot of terrible junk out there and those are pretty important parts.

just ssac stuff. i am running there stuff on my probe and everything works perfect. if the mani cracks, i will just weld it

edit: like this

go nuts!

have fun.

Translation, "Good luck!".

Just buy the greddy kit. You'll be up and running in no time with minimal problems and straight forward upgrade paths.

IMO the 3 most important things in a turbo kit are:
The Turbo
The Manifold
And Engine Management
You get what you pay for my friend. Dont buy shitty eBay stuff.

Seriously, it won't be worth the continued pain in the ass.

Shoot, anything bad happens, a whole new set of parts is only $170 :gay:

Might as well buy a bunch of them at the start!

All that is shiny isn't worth the s/h. Works great for a civic exhaust, though! (OBX)

i have been runing ebay turbo, wastegate, bov, intercooler, and pipes on my probe for a couple of years now with no problems. the problem most of the time with the ebay stuff is not the parts, it the person using it. and i am not going greddy, i would rather peice my own together

dude you megan raicng haters suck, if braced and done righ the can make big power on it. It is the same shit i started with. So all you Haters :gtfo:

By all means, go for it. Just be completely honest of your experience so we can learn from it, good or bad. Honestly, I hope its good. And pics too.

First, you've read through this right?
https://www.miataturbo.net/forums/showthread.php?t=4288

Overall, looks like a good start for about 7-8psi.
With stock injectors, even with the 255, you'll run out of fuel after that, and with just 6* of static timing, I wouldn't run any more than that. Brain might tell you it's OK to run a little more if he's up for some calculations.
Have you sourced an oil feed/drain line yet? How do you plan to route?
Most of us peform a fuel rail mod to make it dual-feed.
You can skip the 02 clamp if MS in definitely in your future.

I ran the .48/.49 DSM for awhile and had a huge boost overshoot problem... granted I was spiking to almost 18psi, but you can expect to spool by 2000rpm's with 8psi by about 3000rpm... and then a smooth decline to a steady 6psi to redline. The cure seems to be to port the wastegate hole or engineer a helper spring. I'll have the results of my new .80/.64 T25 next week.

I think you'll want to look into heat shielding with the top-mount manifold. I'm thinking about melted brake reservoirs! If you're handy with the welder, some sheetmetal stock will do fine. Just look through the VBGarage for ideas. There's also a turbine-blanket in the group buy section.

My biggest piece of advice is to do it right from the start. I cheaped out on my initial build and have been playing catch-up for 6 months. It souds like you've got some prior turbo experience and some decent shop skillz, so you know what I mean. Do us a favor, fill out your profile, signature, and throw up some pics in the vbGarage. It'll help when you want advice. Where are you located, there might be some locals around to help out in person! You definitely came to the right place. Keep us informed.

thanks for the post man. this isnt my first turbo car, i built up my other car in my driveway. but i have never messed with FMUs and stock injectors. i was just going to use the port on the block for the feed and tap the pan like in the FAQ for drain. and i know mitsu turbos are water cooled and from the pic of the oil drian, it looks like i would just tap into the coolant line under the manifold for the water.

Did anyone catch that he wants to use a DSM turbo? Isn't the DSM flange different from the standard SR20 T25 flange most of us use?

he has the megan racing stuff in mind and mentiions DSM turbos i dont see a contridiction. check his hyper link.
+ no where in this thread has he mentioned the use of a nissan t25

yeah, i thought that the ebay manifolds where the mitsu flange?

You are correct.

I have it, it fits. Sorta. Nothing you can't handle though. It sound like you know what you're getting into, so as long as you realize the limitations of the parts you're building with, knock yourself out. :)

As for the water, yes just tap into the coolant line.

Get a 190hp.

As S(p)amnavy said, I too cheaped out on my build, except I really cheaped out. All I can think about now is starting over. YMMV. Best of luck

thanks for the help guys. also what spark plugs is everyone running? i really like to run NGK v-powers, just get one colder?

Yes. BKR7E-11. I was in a rush and had to use autolite 3922s but no problems. Definitely get a $20 fuel pressure gauge and you should really consider a used adjustable FMU. Its really easy to adjust your base pressure and max boost pressure. Huge advantage over the vortech, which you can ebay.

i have a standard adjustable fpr with a guage right now. it also reads boost, but its only a 1:1 ratio :(

my problems with the megan have been with the bottom down pipe bolt... its retarded.

oh and it didnt fit so I had the bottom part cut apart and fixed. had the flex moved back towards the first bend and the rest is 2.5 pipe.

new
http://jazz.sdsc.edu/photo/showimg.p...d/DSCN2435.JPG

old
http://jazz.sdsc.edu/photo/showimg.p...d/100_0364.JPG

cuting and welding is not a problem. i know it will have some fitment problems, you cant expect one jig to work on a million different cars

also i have been looking at the FAQ again. the whole injector thing and AFM thing is confusing me. so we can actually run bigger injectors on the stock ecu by just adjusting the AFM at idle? so if i were to run bigger injectors, just run a smaller fmu disk? i plan on running whatever the 14b is stock, i think its like 8psi?

The stock AFM has been shown to idle up to about 330's with no adjustment. It'll run a tad rich, but nothing to really worry about. The idle-mixture screw is just to get it to idle a little leaner... but it will idle just fine.

Plug the numbers into the equations in the FAQ. You've gotta know how much pressure your fuel pump can supply. Test it, or ask what others are getting out of the 255. Then plug your numbers into the equation. You're gonna find that the limiting factor in your current setup is the stock injectors. Invest in larger injectors... 305/310/330 are cheap and allow you to run less fuel pressure or a less aggressive disc, or both. 8psi is fairly low boost. There's lots of things to tweak, but with the Vortech and it's limited adjustability, you've gotta do the math to see where you stand. Or just trial and error with a WideBand to get a respectable A/F.

well actually I would expect one jig to fit a million different cars. racing beat headers dont seem to have this problem.

my motor sits in the stock location, and the downpipe hit the tranny, and didnt reach the stock location of the stock header, also the 4th downpipe bolt point is basicly impossible to get a bolt through, and wrench on, or turn a nut on a stud. its shit. when I have a little more cash Im going to get the part where it attaches to the turbo massaged to work.
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oh stock 1.6 afm seems to idle my 330's fine. no adjustments.

so just grab some 330s and put them in? and does adjusting the afm afect the whole rpm or just idle? i have a aem wideband, so thats not a problem either, just have to pull it out of the other car

It only affects the idle, and it will idle just fine with the 330's. It will be rich and you'll smell a little gas, especially on a cold-start, but do the math. For 8psi, 330's are overkill. You'll do fine with the 265cc 1.8 Miata injectors. When you go MS, you'll want to upgrade to 440's or bigger, so going 330's now is just something else to adjust. You won't need to adjust anything if you throw in the 1.8's.

I went with 330's because my first goal was 7psi, but that got bumped to 10psi and my ultimate goal bumped from 10psi to 14psi...

your 1-1 fpr isnt going to help you much man you need a real fpr those ebay types wich i assume you have are good mostly for NA cars in wich you set the static presusre how you like the best bet is in a add on fpr with gain adjusted on the fly or by swaping the diaphrams.