Build: VVT and JRSC in 93 NA
 

So, here's the plan for my build. To put this:
https://www.miataturbo.net/attachmen...ine=1365272220

and this:
https://www.miataturbo.net/attachmen...ine=1365272220

into this:
https://www.miataturbo.net/attachmen...ine=1365272220

My plan is to use the stock 1.6 ecu. I have the complete JRSC kit for a 99-00. And just to keep things fun I also picked up a 99-00 intake manifold. So that's the build, thoughts?

I am not entirely sure what I need to change in the JRSC kit to make it work though. Which dummy throttle body do I need? Which actual throttle body? Do I need a 1.6>1.8 throttle body adapter still?

Oh, and just to get it out of the way, I know this is Brain's realm. But I want to keep the 1.6 ecu for cost and driveability reasons. I don't care about the extra hp I'm giving up. I know 99% of you use standalones so I'm against the grain here.

A VVT engine with the stock 1.6 ECU? Might as well run the supercharger with no belt to keep it simple.

Alright, alright can we just get past this and move on to the build?

By the way, I do have a vvtuner to run the vvt, if that's what you are referring to.

Not likely. Explain to us how you're going to accurately deliver the drastically different fueling requirements of the VVT+JRSC combo.

we can't get over the massive amounts of fail. so no.
you're using a JR m45 which is way undersized. fail
then you're dropping in a nice newer engine with a failaids stock 1.6 ecu. fail
what is there to talk about besides the massive fail?

Well, I'm not sure which way to go. The kit came with a walbro and from what I understand the vvt injectors should be able to handle the fuel delivery with an afpr. If not I could put in some toyota or rx7 injectors if needed. I have not done the calculations yet or know the flow rate on the walbro as the kit just came today. It also came with a JR timing boost controller to prevent detonation.

Those are your opinions, not facts.

Digging into this a little deeper...

I just did the calculations and for a target of 180hp I came up with 327cc's so it seems like there are several injectors around that range that will support this swap. At stock 43.5 psi fuel pressure it looks like 626/mx6/probe gt injectors will work. I'd prefer the newer style injector so I could get a smaller, better injector and just bump the fuel pressure up a bit.

Does mazda measure hp at the wheels or at the crank? I figure the JRSC will give another 40 hp, but if the mazda numbers are at the wheels I might need to bump the hp numbers up to 200.

After googling the Walbro, it flows 255lph which is more than enough for anything I want to do.

Does this sound about right?

Hmm, looks like the 1.6 ecu won't idle properly for anything over 305cc. Looks like I'll have to play with the fuel pressure, maybe rising rate?

The problem is less about the amount of fuel and more about the shape of the curve.

The 1.6 liter motor and the 1.8 liter motor have drastically different torque curves. Let's start with a chart. This is three different pro SM motors, all built by Jim Drago. Run 11 is the 1.6, and run 12 is a VVT 1.8. (run 24 is a '99 motor) You can see the drastic difference in torque, espcially down low. This is where the 1.6 ECU is going to struggle to compensate - you're adding a ton of airflow and not backing it up with any additional fuel in that region of the map.

https://www.miataturbo.net/attachmen...ine=1365281513

You're then compounding that with the addition of a supercharger, which will further increase low-end torque and compound the problem.

Long story short, you have two options. You can bandaid it together and you'll end up with a car that doesn't really idle right, doesn't really transition from <100kpa to >100kpa right, and makes less power and torque than it should. Or, you can swap to a standalone ECU, ditch the VVTuner, and end up with a car that idles and drives like it came with a VVT+JRSC combo from the factory, AND makes more power than the bandaid combo ever had a hope of making.

You're putting all this time and effort into the swap - why would you cripple yourself by skimping/being lazy on the most important part?

Well cost, for one. How much would an ecu cost built for my setup?

Second, is your quote "idles and drives like it came from the factory" an overstatement? I have read a lot of complaints regarding things like idle on standalones like the ms. I don't doubt for a second you can make more power with one. You can make more power on a geo metro with a standalone. My goal is to build a car that, once it's built, you can forget that it ever had anything done to it and looks, drives, and idles stock (but with more power obviously). Build it and drive it for 80k without futzing with idle, air/fuel curves, mixture ratios, etc.

And the cost. I only paid $1500 for the car and it does have 190k on the body.

The last thing I want is a tuner car. As I said, I want a stock looking and driving vehicle. Well, as stock as a supercharged vehicle can look. For example, the kit came with a bunch of blue and red silicone couplers and reducers. I will be changing them all out for black.

You are coming at this so ridiculously moronic that I just don't know what to say.

I'm serious, this isn't just a flame post.

You're spending a ton of cash on a vvt engine swap, a supercharger, and whatever else needed to do this, then questioning the cost of an MS3 which you can get for 700 already built, or even cheaper if you do it yourself.

Then you question the consistency and smoothness of operation of a Fully stand alone engine management system that is years more advanced then the 30 year old band-aids that you consider running on this car.

Seriously?

I suggest you step back and try to comprehend how idiotic this all looks to the rest of us.

I'm done here, so you don't go on crying that I hurt your feelings. Good luck.


PS: the part I bolded REALLY made me laugh. With band aids and with a roots type utilizing the dummy TB setup, you will have THE WORST OF BOTH WORLDS. Not even kidding. Your idle will blow, and everything else will be horrifically inefficient or inconsistent. I've actual real world wrenching and driving experience with both "ROUTES" being discussed here.

Thanks for leaving my thread as you have nothing productive to add it seems.

Sav, can you explain what I'm looking at with these dyno charts. I understand the charts will look different. They are vastly different engines. What is unclear is what this has to do with the ecu. Let me explain.

The amount of air coming into an engine is fixed. Now that I am adding more air, we adjust the fuel to match. Why does it matter what ecu you are running as long as the a/f mixture is correct? This can be done mechanically or electronically. Since I don't want the expense of an electronic solution, what is wrong with a mechanical solution? People have been doing it this way for 100 years. I just feel like you can get it pretty darn close this way.

ahh, so you're one of those too stubborn and stupid to be helped.

k

no problem
Oh this should be stickied:bowrofl::bowrofl::bowrofl:
:bowrofl::bowrofl::bowrofl::bowrofl::bowrofl:
:bowrofl::bowrofl:



99% sure this guy is trolling.

Weren't you leaving?

Now I'm gonna stay just because you said that.

And to laugh at you.

You know, you sure have a big mouth but I am doubtful of your intelligence. Usually it is the loudest ones too, because they are the most unsure of themselves and need to compensate.

Yep, that's exactly it.

Does anyone here ever explain anything or is it just a circle jerk of self-superiority. It's funny, because I got a stock welcome PM from Braineack saying how this is a respectful place. I should question someone with nothing better to do in 5 years than to post nearly 18 thousand times.

Anyway, gasoline burns best at a certain ratio, say 14.7:1. Adding more air via a supercharger throws off the ratio, which you must add more fuel to compensate. Now, I can do that mechanically with fuel delivery. The curve may not be exact, as the 1.6 ecu is expecting certain things at certain rpms which are now off. But you can get it close enough. So that is my thinking. Is that not correct?

This post is a flawless, perfect, supreme example of why we haze n00bs on here.

Anyone care to comment who has hit puberty?

It is very obvious that you lack experience. Every person on this forum will tell you that it is a waste of time without an ECU.

You can forget about getting any help from members here until you ditch the idea of the stock ECU. Even if it takes longer to build it, do what ever it takes to get one. You have no idea how much better your life will be, and how much better the end results will be.

This is the equivalent of taking the B6 out and putting an SR20DE or a 4AGZE in its place - it's a fundamentally different engine with completely different calibration requirements. You aren't just "adding more air" - you're drastically changing the engine setup, and that means you need to similarly change the engine's calibration. You cannot do this with the hardware you've described so far.

I did not "overestimate" anything in reference to standalone ECUs. In fact, the setup you're talking about building (a hotside roots blower) adds so much throttled volume to the system that the stock ECU seriously struggles to keep control of the idle. Adding an intercooler will make this dramatically worse, and the car will never idle right. If you switched to a standalone, it's fairly easy to compensate for all of this.

At the end of the day, if you don't want a tuner car, you're making a big mistake taking on a DIY project like this. I don't mean to be insulting, but it's pretty clear that you have very, very little understanding of how ECUs and engines interact. I understand that your goal here is to just avoid the ECU part of it, but what I am telling you here is that you don't get to do that just because you don't understand it.

What experience or example has made you think that you can get it close enough?

You're making an assumption because you want it to be true. It's not true. Sorry. You will not be able to fool the stock 1.6 ECU into properly fueling a VVT+JRSC combo, regardless of what mechanical kludgery you use.

Why would I do what someone just tells me without explaining why? I never spend my hard-earned money like that. I'm just looking for some information.

Thank you for the info. The example I can give is achieving a proper a/f mixture under wot at a given rpm I wish to target, which for my daily driving is around 4500rpm.

???

Go to the ECU section on this forum and spend some time reading the stickies and as many threads as you can. If you are a verbal kind of guy, may I suggest you get in touch with vendors here that supply ECUs. I gaurantee you will find that a Megasquirt is the way to go. Megasquirt is the most economical and well supported ECU on the market for Miatas. Most members here have it.

Here's the thing that's bugging me. You can run a JRSC on a stock ecu. In fact, the vast, vast majority of them were done this way for 20+ years. You can also do a vvt swap with a 1.6 ecu. Many people have done this as well. It is no different than any other 1.8 swap that has been done thousands of times on the 1.6 ecu other than adding the vvtuner.

Maybe this is the wrong forum to ask these questions. I knew what I was getting into as I stated in my first post. I know who started this forum and I know the kind of users that are on it and they everyone is very pro-standalone. I've been lurking for a long time. Oh well, just thought I'd give it a shot.

Cool. What about 2000, 3000, 6000, and 7000rpm? How about at 30kpa, 80kpa, and 140kpa? It's easy to hack a setup together to deliver fuel properly at one particular RPM, but what I'm trying to tell you is that you cannot fool the 1.6 ECU into properly controlling a VVT+JRSC setup at all RPMs and boost levels. You will end up with certain places that are tuned perfectly, and certain places that are either undriveable or unsafe (or both).

That's what I was getting at earlier with the dyno curves. You're changing the shape of the torque curve dramatically, and with that change comes a change in the required fueling that will vary from low RPM to high RPM. RRFPRs only make 2D adjustments - they won't compensate in the low RPM range without making the same compensation in the high RPM range, regardless of whether the compensation needs to happen at both places or not.

A standalone lets you make the adjustments necessary at every RPM and every boost level, and leaves you with a car that drives like it was designed to have a VVT+JRSC setup in it from day one.

News to me. 1.6>1.8 swaps on 1.6 electronics are pretty common, but the head design and torque curves on 1.6 and early 1.8 motors are fairly similar. Once you talk about swapping to the 99-00 head, the 1.6 electronics aren't held in particularly high regard, and going to the 10:1 pistons and VVT torque curve puts the 1.6 ECU way out of its league.

Again, you're lacking a fundamental understanding of how engine management systems work. What you want to do is not safe or smart, and you shouldn't do it.

You know, maybe it is possible, but the run quality would be so bad, that it would drive most of the members on this forum crazy, and I doubt that a build like that would last very long. Remember, the VVT motor has a lot more compression.

I think that once you really take a hard look at the ECU options, and the fact that going from a stock ECU to a stand alone is not such a horrible expense and learning curve, you will do it and have a much better end result.

I wish you all the luck. Think about it awhile before you get to invloved with it.

By the way, Savington has more experience than anyone on this forum when it comes down to swaping in vvt motors, take what he says very seriously.

I'm pretty sure this is a troll post. I would vote for a ban of this n00b, but I'd rather him stick around so we can see his blown engine thread.

Seriously OP, listen to what others have said. A JRSC setup, even on a 1.6, with a stock ECU sucks. A 1.8 vvt swap with a stock 90 ecu is going to suck. A 1.8 vvt swap with a JRSC thrown on it with band-aids is going to REALLY suck.

OP, let me just make this simple.


1) The 1.6L ECU cannot control the VVT motor properly. COPs, the VVT itself, different sensors, etc. all lead to the 1.6L ECU needing to be hacked together to even TRY to run the motor properly. It's like asking a 4th grader to do trig. Yeah, some of the time it'll work out, they may even be able to make a proof of their answer. But that doesn't mean they can do 100% of trig, 100% of the time. The development of the 1.6L ECU is almost 15 years removed from the OEM 01+ cars. Would you expect a 10 year old computer to run windows 7 flawlessly?


2) The 1.6L ECU can run its' native motor, with piggy-back band-aids, using the JRSC. It's not the best system, but it can be done. The thing is, if the ECU is near the limit of its' abilities running a STOCK motor with a JRSC, why would you expect it to be able to handle a non-native motor while also dealing with the JRSC?

3) 14.7, stoich, whatever, doesn't mean squat. For one, the ECU may try to maintain 14.7 under certain conditions, it doesn't mean 14.7/1 is the be-all, end-all, AFR.

4) With enough effort, you can make ANY ECU control ANY motor in ANY car. It doesn't mean it will do it well, reliably, safely, easily, or consistently.



I recommend you do more reading/learning before you go any further. Listen to these guys, they've done a lot. They know what they're talking about. Let them help you; unless you're just trolling, or just really stupid.

Good luck, keep us informed on your progress. If you do not intend on following the advice in this thread, at least keep us updated on how you attempt to cobble this together.

As someone who ran band-aids for years, I can say that you are in for the worst experience of your life if you keep being stubborn and ignoring all the people on here who actually know what they are talking about.

Good luck.

There are two issues here:

1) Fueling
2) Timing

Fueling: The VVT engine needs more fuel across the board than the 1.6. At some RPM/Load areas, it will require significantly more (ie near the redline), in some areas less than that. With a stock 1.6 ECU and a pressure regulator, you won't be able to make the fueling right. You will be very rich in some areas and very lean in others. And since something tells me that you won't even install a wideband, you won't even know, but you will be happy in your ignorance.

Timing: The stock 1.6 ECU commands more timing than the stock 1.8 w/VVT ECU. Add the supercharger (which significantly raises the IAT) and the boost it provides, and you now have a recipe for certain detonation. You need to be able to pull timing somehow, and there's no easy/cheap way to do it with a VVT engine.

Wonder if blow-through carbs wouldn't be easier and safer...
Chop the FW a bit and add a distro as well.

Those electronics are scary...

The dying art is almost dead.

The curve is going to suck ass. it'll be either lean before 5.5K so it's not too rich after 5.5K. or it'll be rich before 5.5K and then HELLA SUPER DUPER rich at 5.5K and then you'll wash out your ringlands and blow the motor.

You're in the running for the prestigious "retard of the year" award.