Compound boost: EFR 7670 into Coldside FFS W/ H20/Meth into 10.5:1 VVT Built Engine
 

Cause someone had to do it.

Currently turbo'd with EFR 7670 at 16 PSI, MS2E engine management.

New setup will be EFR 7670, intercooled with intercooler mounted flush with undertray and a pair of fans mounted on it (hidden but gets clean air), then going into a FFS coldside running a 130/65 pulley. Probably spray water meth right into inlet of blower. Probably gonna spray a LOT. And then to a built 10.5:1 VVT motor. Running on a MS3 Pro with IGN-1A Race coils and 36-1 triggerwheel in factory location with stock crank/cam sensors. Hope to run on 93 octane, but will switch to E85 if I have to.

Already built the engine, EFR 7670 installed. Motor revs to 8700-8800, makes good power, but is laggy from turbo being too big. Gotta move intercooler and build ducting/fan setup for it. Already ordered a MS3 Pro and wiring stuff to rewire engine. Ordered a AEM water/meth progressive kit. Bought a used FFS coldside off of 18psi (thanks!) and ordered the 130mm pulley for it.

Pics of motor build and current setup:

Trubo
https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

https://www.miataturbo.net/attachmen...ine=1373995754

1st :party:

That's not why its laggy.

Why is it laggy then?

:rly:

Then why isn't it making full boost sooner?

In for winning. Glad someone bought that FFS on vlad and is going to use it the right way!

Because you touch yourself at night.

Because of the tune and setup.

Log exhaust manifold. Stock NB2 intake manifold.

"high to mid 9's at full boost" - that's like fouling plugs, 25% power drop rich.

"Ignition timing I won't say but lets say LOW" - that's a great way to skyrocket EGT (especially combined with super-rich fuel)

No mention of boost control (wastegate? ebc?) or VVT tuning :rolleyes:

etc etc

Turbo sizing has a lot to do with it, but in this case it's just a dumb setup & tune.

If you are suggesting my current tune is not ideal, you're crazy!!!!

I kid. Obviously it sucks, I mentioned I tuned it that way to keep it safe (10.5:1 comp, sky-high AITs, no vvt). I know if I tuned it 11:1 and give it more timing I couldn't have made 35 passes at the track without a failure. I can tune a miata, been doing it for 6 years or so. :) It's rich and retarded now to keep my high comp motor safe till I get the setup finished. IE, it's not finished. :)

And my NB intake manifold is ANYTHING but stock. :)

11:1 is still super rich

you built a motor with stock pistons. now you're working around it to make up for the shortcomings of the motor and blaming it on the turbo being "too big"

while this guy has 30psi from a GT35R at ~5200rpm. You make 6psi from a better spooling turbo at 6200rpm.

https://www.miataturbo.net/attachmen...ine=1373999051

Fix your tune.
Fix your setup.

Really? You came here to tell me 9.5:1 is too rich? What are the shortcommings of my engine again? Besides having 250 in the shortblock.

If your engine can't handle 11:1 afr - that would be a shortcoming.

I dunno if it can run 11:1 with 168*F AITs while still breaking it in. Not gonna find out either! I would rather drive it than blow the motor again. I didn't exactly plan to have super high AITs, gotta change my IC setup.

Why you all over my case anyways? Other than stating the obvious. 9.5:1 is rich, 168*F is hot, no timing is not ideal, etc? Things are changing, see first post!

I would be stupid to tune it aggressive when there are problems with the setup (igition pickup issues, AIT issues, wideband at one point, had a tiny boost leak I found too).

Yeap, it's gonna be sweet! I think this is the 18 PSI pulley I bought, so should improve low end torque a bit and help spool the turbo sooner too. Win-Win. (Que someone to tell me I'm increasing the cost and complexity!)

who made that log manifold?

It's an FM manifold modified to T3 bolt pattern and opening, and a pipe welded on w/ 4 braces to support a 38mm wastegate. I made it T3 and made the pipe piece, had an old man TIG it on with a high-nickel filler. Been solid so far and cheap!

So I'm trying to conceptualize this but not real familiar with superchargers. Do they provide a max psi of some sort or will they always provide a constant delta P, So raising the inlet pressure will then directly relate to a raise in outlet pressure from the supercharger? or will the turbocharger just start the supercharger closer to its max target pressure?

Will the turbo not create drag from the supercharger suction at low rpm, then the supercharger just act as a restriction for the turbocharger at higher rpms?

The engine is an air pump. Mine is a 1.8L air pump.

The SC is an air pump. With a 130/65 pulley setup, it will turn two times every time the crank turns once. Motor moves 1.8L of air in 2 revolutions. So the SC will spin 4 times, each time moving 62 cubic inches of air, which is about 4L worth of air.

So blower tried to push 4L of air into a motor that only asked for 1.8L. Bam, boost.

Same story with the turbo blowing into the SC. Only there isn't a 2:1 or 4:1 simple ratio to explain it. At some engine speed, the motor is going to spool up the turbo and the SC will be sucking in 4L of air per 2 revs of the motor, and the turbo is going to blow in more than that into the inlet, boosting the inlet pressure.

Basically it will drive like a SC car down low, and take off up top when the turbo spools.

Yeah I get that, I guess I was just looking at it as what happens when one is out performing the other? will the less performing charger not create a drag reducing the performance of each system if it was running independently? Or is that negligible due to the performance gain? So even a supercharger running at half of its normal efficiency due to the turbo creating drag at low rpms would still be better than no supercharger at all I guess. Or will the supercharger suction just cause the turbo to spool up faster and not really allow much drag from the turbo?

Just thinking out loud here

Either way im excited to see what happens.

So what is the timeline for this shiz? I want to know when to check back.

sounds like it will also create a metric fuckton of heat in the process...

I am impressed that you were able to get the EFR to fit in the engine bay with that log manifold. This just doesn't seem like a very efficient way of creating an awesome power curve though. I have a feeling that the supercharger will end up restricting flow at the top end and just turn it into excess charge air temp. If you wanted to twincharge this thing, wouldn't a compound turbo setup be cheaper and more efficient? Or possibly split the intake charges so that the supercharger feeds the engine until a certain turbine speed is met and let the turbo have it's flow routed past the S/C? After all, that is why we love turbos more than superchargers. The are able to create pressurized air at high flow rates in an efficient manner.

I think you're thinking of extremes. As in both are going to be huge bottlenecks at some point, when in fact they won't be nearly as restrictive as it seems. The charger will push a whole lot of air into the engine at low speeds creating boost and lowend torque, and also resulting in more exhaust gasses sooner, which will help the turbo spool faster, in addition to actually providing torque even before it does. Once the turbo comes on full song, you now have the turbo stuffing huge amounts of air into the blower which is already stuffing air into the engine, and that compounds it creating even more pressure and air being crammed into the engine. Even more so than the pressure of the sc + the pressure of the turbo. So with 18psi from the blower, and lets say 18psi from the turbo, he'd theoretically be looking at some insane amount of air being crammed into the engine, something like 40+ psi.

That's just my take on it. There are much much more in depth explanations to this should you wish to pursue the science of it, but the end result should be pretty promising.
Or how about, oh I dunno, lets just let the man experiment and provide us with some seriously unique, undocumented, and uncommon results if only for our amusement only :)

I mean he's already going through with it. Its not like you dissing the setup is going to make him part everything out and start over.

The only thing that would do that is if the setup ends up not working like he's hoping.

And that we shall see.

IF it works though, its going to be crazy.

what is your goal for this? Are you trying to just create a cool proof of concept? Or are you shooting for a specific performance gain (700hp for example).

Most people who have tried for high power builds focus a lot more of their energy on overall flow capability of the entire system rather than just building more boost. I am not saying that you should not do this or anything. (it is pretty freaking cool after all) This is just not the way big power is made and you will be subject to mass amounts of trolling.

18PSI, Yeah I was just considering the extremes but I guess even if the supercharger is a restriction to the turbo air, it will be repressurizing the turbo air so the restriction it causes will be insignificant. Makes sense I guess

18psi, most, if not all, successful twincharge setups bypass the supercharger at high rpm.

Yes I know. But we don't know yet where the limit will be for it to completely choke up.

We are about to find out :party:

Lol at complaining to be laggy with a log manifold. You better not say you have a small exhaust as well.

Also what is up with your AIT being so high especially when the BW turbos are so much win? On my unhappy over spun m62 heatgun I see AIT of 100 after the IC. On my old volvo with an inefficient ebay turdblow and IC behind the ac condenser AIT below 120. Compound charging will just increase your AIT even more.

Lol @ poverty.

I would totally do this if I had a big pile of money. EFR 7064 and a SC to build enough power to keep spool down. Though an anti-lag setup like Group B used on their I5 quattro engine would be cooler. That thing was a monster.

When one blows more air into the other, you get boost. Not bad. Having the SC inline will suck air through the turbo, but the turbo is spinning and blowing a bit of air so no real gain/loss here it may help/hurt a touch but very minimal, I would guess it helps a tough.

Where it really helps is the SC basically doubling the amount of air going through the engine. This will get more exhaust flowing through the turbine of the turbo, and spool it quicker. So I'll have the boost down low from the SC to get more torque down low, AND the turbo will spool quicker so I get more turbo power sooner.

I'm also excited to see what happens. I've never done this setup before, so don't know what to expect power wise and tuning wise. I more or less know how I'm hooking everything up, just don't know how well it's going to work. Stay tuned!

The SC may restrict flow up top. Only one way to find out though. The SC has a bypass valve built right into it, so it will be easy enough to test with/without. As you say, less heat too so it's a viable option.

Compound turbo would require me completely redesigning my turbo setup, and forget A/C. SC bolts right up, now I don't need a new intake manifold, and will give me more torque down low and better throttle response than if I had a turbo instead. I'd still like to try a compound turbo setup on something, one day. Probably a diesel though. :)

Goal is to build a fast, fun car, that looks stock on the outside. A fast, fun, reliable car that I built. I built my engine, the head, did all the machining, etc. Not shooting for a specific number, hence why no dynos. I have focused on airflow too. I have 250 bucks and maybe 3 hours in my bottom end. I have 160 hrs and over 2K in the head (s)(scrapped a couple for R&D, I know where all the water jackets are).

I dunno how this will work, I think it's gonna have a ton of low end torque and hit full boost by 5K with MUCH improved time to torque numbers. I think I might find the limit of stock 10:1 pistons. I might break the trans or diff or axles. I don't expect every person on an internet forum to approve of what I'm doing. I'll just keep doing it anyways. ;)

I had a hot air intake, and a small IC with not enough airflow too close to the radiator. I experimented, it didn't work (like I thought it would). So I'm changing it. Can't be right every time!

At least let the guy give it a shot before we all jump on him. GOGO Pat! I want to see some data on this setup asap.

The Blower wont restrict flow. It will make heat which will be what limits you. You see, this setup will be somewhat hard to control boost on. For simple sake lets just assume that the blower is working on a fixed 2:1 pressure ratio. That means if the turbo isnt spooled (0psig at blower inlet) you will be making 15psig in the intake manifold, now if the turbo is outputting 15psi at the blower inlet you'll have 45psig in the intake manifold, and a lot of heat. If the bpv on the blower has its vac hoses routed like stock it'll stay closed when there's more pressure in the manifold than the blower inlet. The blower moves a fixed volume of air and not at fixed pressure ratio so it is a bit more complicated than the above. Also, proper intercooling of the air charge between the turbo and the blower is going to be crucial.

I think this is really cool, but it makes me pause for a why. This turbo should be spooled by 4.5k on a 1.8 miata with a decent setup, shifting (especially @8500rpm) shouldnt drop you out of the power band. You mainly drag race this car so I don't see why you care about the lower 4krpm of the rev range when you shouldn't ever see that during a race assuming you don't mess up the launch. And you have a jesus EFR turbo, even that massive thing should have better throttle response than some crappy journal bearing jobby made in china.

I still want to see you do this.

spray the house down with e85 to battle the heat (run it EVERYWHERE lol: main injectors, aux injectors, spray nozzles, whatever) and go for glory :party:

I now know from personal experience that you absolutely have to use the aux injectors that are in the manifold, otherwise you're gonna have a bad time

I agree it seems this turbo should spool faster. But it doesn't. I've checked for exhaust leaks, boost leak test to 25 PSI, can't find a leak if there is one. Turbo spins freely. It could possibly be blowing the internal wastegate open, that's one thing I don't know is not happening as I'm using an external gate. I need to bolt that gate shut just to prevent that possibility.

I also agree about proper intercooling. This is something I'm going to be redoing. I have to take some measurements to get a better idea of what I can do. I'm going to put the biggest one I can with a pair of badass fans on it.

Do you have the VVT hooked up yet?

VVT isn't hooked up yet. MS2 won't control it, but the new MS3 will. It will be hooked up when I put the new ECU on.

There's your problem. I tried to drive the car once with the vvt noid unplugged. I thought I lost all compression it was so slow and didnt build boost.

I believe Sav said he thought it would be a 500 RPM boost in spool. That would be great, but still seems high. Current setup is 16 PSI at 7K ish. It would be great if VVT helped a lot.

Any numbers? I think y8s tested this on a dyno a long time ago and there was a difference, I actually don't remember how much though...

big difference

https://www.miataturbo.net/attachmen...ine=1374018533

I didn't drive it very far because I thought I legitimately broke something (just forgot to plug something in instead). But my car normally hits positive manifold pressure just above 2k in higher gears and "full boost" of 6psi before 3k. With the VVT unplugged I had almost nothing at 3k, just cresting into positive pressure. And then I immediately turned around and drove home babying it. Thats the best I can do for numbers, and that on an efr6758, running a 6psi wastegate on the wastegate only.

Well I didn't think it made that big of a difference, but it sounds like I'm wrong. I REALLY hope it helps as much as you experienced.

lol I keep forgetting you're running this thing without vvt control. actually even worse: its fully retarded all the time.

there are over a handful of major things holding your car/setup back.

sounds to me that with everything you're doing, once its squared away it will go from mediocre to 5x overkill LOL

tuning afr, getting ait under control, having a sc pushing 18psi, controlling vvt, and getting the timing in check will make the car feel so different you will piss yourself

start planning a drivetrain upgrade and driving on slicks full time

Well I have a 6 speed and RX7 LSD in an RX7 case with stock 99' one piece axles right now. I would love to get the drivetrain beefed up better, but it doesn't look like there is any bolt-in solutions stronger than what I have. I dunno what transmission I should eventually install, but the rear diff, it looks like the 8.8 ford setup is the way to go. Hopefully the 6 speed and RX7 stuff holds up for a while.

And yeah, when I get all the stuff fixed and dialed in, it should be fun. :)

I intend to do this with a toyota SC14 and something big and cheap (T04 or something).

The sc14 will be mounted below the turbo, allowing intercooling of both, I also intend to spray before the blower.

SC14 also has a bypass for experimenting with it. Although I know an SC14 can do 400whp on the right setup on its own, so I dont see it becoming a restriction unless I went for the ultimate record.

Dann

I can't even picture this...Will your car have no hood?

Yeah I'm kind of confused here too. You need to intercool between the turbo and the blower and between the blower and the engine. One would argue that the intercooling between the two compressors is more important than the one between the final compressor and the engine.

huh?
I don't get that part at all either.

If you take hot air and compress it again you get REALLY REALLY hot air, which after being intercooled will just be REALLY hot air. If you intercool hot air, to be warm air then compress it again it'll be rather hot air. It has to do with thermodynamics that I cant quite remember off the top of my head. Basically compressor efficiency will be higher with lower intake temps. The equation is coming back all fuzzy right now. I'll probably wake up at 3am and remember it. :rofl:

I think making serious power (500whp) when your final compressor stage is unintercooled is a pipe dream, no matter what's happening in between the turbo and the supercharger.

If I were to attempt something like this, it would involve a low-mounted turbo and a hotside MP62. Either feed the blower through the turbo's compressor wheel or feed them both into the same intercooler. Feeding the blower with the turbo could work, but I'd be concerned about boost control.

Boost control on this setup is going to be difficult. It would probably be easier to control the turbo based on desired pressure at the blower inlet than trying to control it based on the manifold pressure.

Air filter
Turbo
E85 injection
Big throttle body
Supercharger
Intercooler
Intake manifold throttle body
IM
e85 injection again

Combustion.

Like that.

A low mount sc14 with a sidewinder manifold, kind of like crtndrftr's manifold.

Fed into a front mount, with a rear mount radiator.

I have an NA shell just sitting here about to be chopped up and a personal challenge on the aus forum to build a car that does x time for 5k. After that, Ill go nuts on it with the big turbo and blower.

Dann

Yes, EBC with reference between the turbo and blower, an sc14 will give a constant (ish) pressure ratio so controlling boost going into it is where its at.

According to my logic.

Dann

Great to see someone brave enough go against the grain and build twin charged engine. My hat's off for you sir.

Few thing's that came in mind.

1. why dont you get better flowing exhaust manifold?
2. how will you control IAT?
3. how will you control boost?

Here's a video to keep the spirit high.

To nitrodann
Why are you going to fit the SC below the turbo? Why not fit it like hotside on top off the exhaust manifold?

Then just a thought. Instead of using old school SC blower, one would use Rotrex (like in the video) with proper gearing, it would be easier to install, would create less heat and off course SC would be more expencive to buy..

Then use a teenie tiny turbo to 'spool' the rotrex?

Dann

it's a bad thought. a very bad thought.