The wify's MX-3. . .

[wheelhop]

back when I was running 5psi. . .



It now builds quickly to 3-4 psi and creeps up to about 7psi. ALLLLL i need for what I want. This is a very fun machine!

[wheelhop]

Shot of the manifold to turbo and where the different intercooler ended up sitting.







If you go back to the first few photos, you can see how sleeper it looks. You CANNOT see the FMIC at all looking at it from 10 feet away. nor can you looking over it starting at about the same distance away and moving towards it. The turbo quiets the exhaust down (have a rice-cake muffler on it); so it is quiet and smooth. I am very suprised how quiet it is actually. You hear the intake over the exhaust.

[wheelhop]

I ended up running the stock fuel injectors and a BEGi fmu and a wally 255hp in-tank fuel pump. I did not modify the fuel pump to do away with the +85psi bypass. 85psi with the 190cc injectors are plenty with that pump. I have more than enough fuel for 7-9 psi with the td04h 13g in the 5cm^2 turbine housing. It spools the turbo plenty fast enough, hitting 5psi before 4k without a ball and spring boost controller (using a fuso 20g wastegate actuator because it agrees with the angle i have to clock the housings for everything to work). If a ball and spring controller is used, it spikes to 8 psi then settles to 5 at 3300rpms . . .Far too quick for my comfort level. The universal BTM is VERY VERY well suited for this setup. I simply pull timing when boost tells it things are going to get crazy, and I dont feel a loss in power or a transition or anything. VERY good investment.

In all, the mx3 1.6L motor LOVES boost. It runs smooth through to redline. The more throttle you give it, the more it likes. The rods apparently handle the "boost" just fine. Which means that with this turbo, 8psi at the timing curve I am producing and the fuel I am flowing is just fine for months of abuse. Totally different animal than when I had the big muffler, no turbo, highflow intake, and k&n filter, with the timing set to 15deg advance vs. stock 10deg. I am even running the stock intake box and actually threw in the stock paper air filter, as you can see in the pics. I never put timing back to stock. I just had the btm take more timing out when on boost. So throttle response is the same.

So far, I am very pleased with the little 1.6L SOHC motor with boost and would deffinately do it again if I had to. I never had more than 2 days of down time. It is daily driven from Sanford VA to Birdsnest VA.

[wheelhop]

When I mean 'never had more than two days of down time' that means DURING the build. I didn't do any engine swaps. I didn't do any head swaps. It was down no more than 4 hours of wrenching at a time. It's nice to be able to alter the power of a machine so DRASTICALLY without having it sit on it's a-- for weeks at a time. a BP swap is all fine and dandy. But this route works well if you plan it out and execute effectively. Universal BTM, BEGi FMU, fuel pump upgrade, mild turbo, welding skills, tis all.

[wheelhop]

Also like to add, that the stock VAM clicked down about 15 clicks tighter is plenty to control the fuel injector sitting at 60psi base fuel pressure. The Walbro 255hp fuel pump I installed overruns the stock FPR terribly. But with the BEGi FMU, i can set the onset pressure to a point where the fuel pressure curve remains smooth as it rises; otherwise, overrun at idle, until close to 0 boost, then drop to stock fpr and then jumping up to whatever you set the FMU to.

[kulluminati777]

the title of this thread says wifeys mx3 but trust me. It may not be today tomorrow or next week but the car will be complete yours one day and she will have something else. Thats exactly what happened to me. I fell in love lol

[wheelhop]

She REALLY likes driving it now. I have an AWD DSM.

[wheelhop]

Some more tweeks. It never had any knock, but I really did not like how long it took the ecu to go to open loop.

How the ecu is behaving:
1) Still trying to find stoich below 3750 rpms at part throttle but full boost, no matter what.
2) Even when warmed up, if I shut her down and restart. Even at WOT (activating the WOT switch), it would still try to find stoich below the 3750 rpm threshold for several miles or a few minutes of driving. But then go back to normal and go to open loop no matter what at WOT.

Activating the WOT switch at part boost won't solve the 2nd problem. But removing the o2 sensor from the circuit at part boost would solve both issues. So I wired the normally closed side of a relay to a hobbs switch and the battery. The hobbs switch actually is adjustable down to about 1 psi! which i thought was surprising. But I need it that low. I set it to energize the relay at 2psi. The ecu sees low volts from the o2 lead and then wants to richen. By 5psi things are running at 11:1 or richer no matter where throttle is. The transition feels smooth and clean, as well.

It was something that put my mind at ease. Everything else is running VERY well. Its a blast to drive.

[wheelhop]

I realized I was running the BTM at 1psi retard per 1 psi boost and starting at 1 psi of boost. I have the base timing set 14 degrees ad vance, 10 is stock. Thus at 5psi = 4 degrees retard from 14 degrees advance at base, which is 10 degees. Thus I was running stock timing at 5 psi No knock and the plugs look nice and tan after a hard pull at that tune:



. . . . . It is apparently very hard to get this mx3 b6 to knock, very much like the miata b6.

Why is it all over the web and even this forum that the SOHC B6 mx3 motor "doesn't restond to boost", "will bend rods at 5+psi", "will not take what the sohc b6 miata motor will take", etc. ???? I think its a bunch of entrweb experts believing their own opinions to be fact.

[wheelhop]

Here's a plot of the B6-ME on the 13g compressor map.



The 13g compressor works quite nicely for the B6 with the spool the td04 5cm^2 turbine gives it. This is at 6psi (1.41PR per the map). The VE is the **Engine** VE not the total VE. Total VE would be close to 150% of course. Your torque curve typically runs parallel to engine VE. So it appears that at 6psi the peak torque (between 4krpms and 5krpms) falls into the 78-80% compressor efficiency range. That's about as good as you can get.

[crazycanadian]

Glad its all working out bud... Enjoy reading your info and how in depth you are getting into things..

Looks like your plugs all though coloring looks good they are worn out... You can see the back sides of the electrodes are worn off..

[wheelhop]

Yea, those were the original plugs when I bought it. I swapped in some NGK plugs that are a stage colder. Which is the 6's. Factory replacement are 5's.

****EDIT: The number for the NGK plugs in her now are BKR6E-11.

[Killerbee_313]

i see this thread hasn't been updated in a while, but WHEELHOP, with those simple mod's made to your 1.6L, what do you expect the Power output to be over the stock engine? And have you done any Dyno pulls or Drag Times? Just wondering, VERY interested in doing this Turbo upgrade to my SOHC 1.6L as well, but possibly using the VW's 1.8T Turbo, I believe it to be called a K03 Turbo? What do you think? Thanks.

[wheelhop]

Well, per the compressor map, and assuming the engine VE of the SOHC B6 is around 85%, that puts the airflow at over 16lb/min. For low compression turbo ready motors, that is about 160 crank horsepower at 18 degrees timing at peak. The naturally aspirated B6 runs about 1 to 1.5 higher in compression ratio. So with the timing set where it is and that stock compression ratio, it would be safe to say that it's sitting at around 160 crank hp.

My 70-90 times go along with that. But best bet is to get to the track and get MPH and weight calculations. But, it's difficult to convince my wife to take the time and do that. "It's fun, so who cares" is a tough argument to get around since Delmar is over an hour away from me.

That turbo is likely a good size for the B6. My 13g comes from an automatic 2.0L 1991 Eclipse. The manual transmission turbo is larger, spool would be a bit later. Most manufacturers put slightly larger turbos in manual transmission versions of their turbo platforms.




One thing I just did that has made a real difference is a swap to a K & N air filter and cold air ducting. The spool is noticeably quicker and the throttle response is much sharper in or out of boost. The stock cat is still there in exhaust. In fact, the entire exhaust is stock except for the muffler upgrade (semi flow through style). I'm sure the richer exhaust gases are closing up the stock cat a bit. So that is the next thing to go. . . All these mods are following the principle: "it's about flow, not boost." I could turn it up 2 more psi and stuck with the stock air intake and continue with the stock cat. But summer heat, high compression, higher boost is more detonation prone. More flow at the current boost is giving better throttle response and the same power as higher boost, all the while being safer to the engine and more reliable.

[Killerbee_313]

Wow, thats alotta good info at once, I wish everyone was nearly as thorough as you Wheelhop!

As with your "Flow over Boost" argument, I agree with you completely. I was considering this setup:
K03 Turbo (VW 1.8T turbocharger)
Front mount intercooler (One of the Ebay kits)
High Flow Filter (Prolly not cold air, but def not stock box)
High Flow Exhaust (2" Cat back/Muffler and High Flow Cat to meet emmissions still)
Blow Off Valve (Prolly something cheaper, nothing over $100, vented to the Atmosphere)
The wastegate is incorporated into the Turbo from the K03 so I don't need anything else there.
The only question I have is what about the Vacuum Lines!?? Is there anything needed to be moved around? I kno the brake booster will be ok cuz you don't hit the throttle and brake at the same time so it will work fine, but what about the fuel rail or any other lines?
And...in conjunction with that question, is it necessary to get a higher flow fuel rail, injectors, and fuel pump? planning on running rought 5-8psi.
Thanks for the help!!