Compound boost: EFR 7670 into Coldside FFS W/ H20/Meth into 10.5:1 VVT Built Engine - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 07-16-2013, 04:51 PM   #21
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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.
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Old 07-16-2013, 04:54 PM   #22
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Originally Posted by rigidbigelsworth View Post
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.
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.
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Originally Posted by swimming108 View Post
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.
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.
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Old 07-16-2013, 04:59 PM   #23
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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.
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Old 07-16-2013, 05:01 PM   #24
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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
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Old 07-16-2013, 05:27 PM   #25
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18psi, most, if not all, successful twincharge setups bypass the supercharger at high rpm.
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Old 07-16-2013, 05:29 PM   #26
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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
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Old 07-16-2013, 05:32 PM   #27
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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.
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Old 07-16-2013, 06:37 PM   #28
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Lol @ poverty.
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Old 07-16-2013, 06:44 PM   #29
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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.
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Old 07-16-2013, 06:58 PM   #30
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Quote:
Originally Posted by rigidbigelsworth View Post
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.
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!
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Old 07-16-2013, 07:04 PM   #31
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Quote:
Originally Posted by swimming108 View Post
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.
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.
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Old 07-16-2013, 07:11 PM   #32
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Quote:
Originally Posted by swimming108 View Post
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.
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.
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Old 07-16-2013, 07:13 PM   #33
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Quote:
Originally Posted by cjsafski View Post
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.
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!
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Old 07-16-2013, 07:17 PM   #34
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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.
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Old 07-16-2013, 07:26 PM   #35
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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.
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Old 07-16-2013, 08:00 PM   #36
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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

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
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Old 07-16-2013, 08:01 PM   #37
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Quote:
Originally Posted by Leafy View Post
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.
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.
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Old 07-16-2013, 08:02 PM   #38
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Do you have the VVT hooked up yet?
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Old 07-16-2013, 08:04 PM   #39
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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.
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Old 07-16-2013, 08:42 PM   #40
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Originally Posted by SleeperMX-5 View Post
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.
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