Warpspeed

O/k thanks Pat.
I think the first decision when planning something like this is to select a suitable supercharger and turbo. I won't go into all of that right now.

Anyhow, I bought a front entry TVS1320 which was originally for a Jaguar/Landrover three litre V6 engine.
These are a physically quite a large supercharger with a long drive snout and the stock 62mm eight rib drive pulley.
So the first job was to chop off about 120mm of snout. That turned out to be quite easy, and a custom drive flange was pressed onto the shortened blower drive shaft.
Onto that flange was bolted a 104mm seven groove BMW waterpump pulley. There is also a similar 112mm BMW pulley available if I need to change ratios.
The crank pulley is a standard 130mm six groove FFS part giving the blower a 1.25 : 1 step up ratio.



Here is the new shortened snout with the home brew drive flange (.005" press fit) with the original Jag pulley and the new BMW pulley.


Now some trial and error junk supercharger mounting brackets were fitted to the BP block.
It took a few goes moving holes around to get the blower absolutely parallel with the crank, and spacers are used on the long blower mounting bolts so the blower can be moved back and forth on the long bolts for perfect final pulley alignment.
Long experience and much trouble with blower drives has taught me that getting things absolutely square and in line is absolutely critical to success.
Fortuitously Mazda provided a pair of ideal bosses on the engine block for mounting the front of the blower.
You can also see in this picture the power steering pump mounting bracket made from two pieces of heavy 5mm thick steel angle secured between the original three power steering bosses on the block and the lifting point on the cylinder head. Its very strong and stiff and dead in line.

The point I am trying to make here is don't be afraid to move other things around to get the most ideal supercharger location.


There is also a diagonal stay to stiffen up the whole supercharger mounting and help to prevent any resonant vibrations from developing. Its a bit difficult to see in this picture, but it ties the supercharger to the lifting point on the cylinder head.



That is really where I am right now on the hot side of the engine.

Next comes the cold side where I am hoping to use a cut down Nissan GTR induction system with individual throttle bodies.
Am at a very early stage with that, but so far so good.


The very last thing to make all this work is the supercharger air bypass.

This is a bit of a Frankenstein device that uses a normally closed two inch stainless steel exhaust bypass butterfly valve in conjunction with a Chinese dual port wastegate actuator.

You can buy two types of these valves, normally closed (that open under boost pressure on the actuator) the actuator rod pushes under boost.
The opposite type is normally open (that closes under engine vacuum) and the control rod pulls the valve closed under vacuum.

I used the push under boost type. These valves come in two inch, two and a half inch, and even three inch sizes.

The dual port actuator has a very light spring that keeps the supercharger bypassed whenever the differential pressure across the throttles is high (engine vacuum) and fully closes the bypass if vacuum falls below 2.5psi or 5 inches of Hg. I have used this system many times and it works wonderfully well.

That is really the lightening tour of my project.

Ted75zcar

iTrader: (2)

Ha, good to see you are considering going back to the dark-dark side! My compound has been on the road now since early 2018, and if I make it to Feb. 2021 without anything popping up, it will be 12 months with ZERO issues. Over that time it has seen 25+ psi with literally hundreds of WOT pulls. I cross 250 lbft (uncorrected) by 2800 at 5280ft and hold that to >6000RPM. Compounds are sweet. Only LFX/LS swap people will be able to relate to how a compound actually drives. While I have never driven a Tesla (or any pure EV) I suspect the feeling is similar.

With my 3.3 rear end, I have no need to go over 4krpm unless I am getting on it. The amount of time spent at positive pressure ratio is really high, there is no "in-boost" state during driving. Only more torque, constant torque or less torque, shifting is not required. Don't believe any of the BS people will say about lugging the engine. That is total hogwash. It is all about the tune.

As far as the whipple is concerned, the last compound I built used a twin-screw (OA2076). Now that system was on a 1.6, but it absolutely ~felt~ faster on the low end than the current built/ported OS/VVT/1L roots SC/BB turbo/1.8 I am running now. I am confident that if/when I get that motor back on the road in proper form, I will be able to hit that 250lbft by the same rpm if not earlier. The switch to a roots style was purposeful. As this is primarily a street car (full flex) the internal compression ratio of the twin-screw would cause the SC exchanger to reach a steady-state temp that was quite a bit higher than ambient. The roots today does not do this. The second issue I had with the twin-screw is that those technologies have superior carry-back/leak-back characteristics. While this would seem to be beneficial, it resulted in extreme pressure spikes on the SC outlet during transients. While I wasn't ever able to link those nearly instantaneous pressure spikes with any ill-effects, they did concern me. That setup was only on the road for ~ 12 months. The third issue is that high RPM where my SC is nearly completely bypassed, I am no longer investing any crank energy into compression that gets thrown away. As I think you found on your original monster SC setup, the SC taps a crazy amount of HP at high RPM when it is performing any sort of compression (internal or external).

The really awesome thing about the compound is that it is HP that determines TC spool (from a turbine side perspective). People seem to be oblivions to this, but it is crazy obvious. HP = heat + air. I have been bouncing around these forums for a while now, and the simple lack of fundamental understanding of how turbos actually work blows my mind. So anyway, if the SC provides additional HP at low RPMs, guess what happens? The turbo spools faster. This is not insignificant ... like >1000RPM faster. It may look like you are only using the SC for a small portion of the power curve, but this is simply because it allows you to transition to the better/more efficient compressor earlier.

I am stoked that you are thinking about doing this. I only know of 3 systems on the road right now, There are lots of people who talk about doing this, but very few ever actually follow-through. I have been following your work since (my) day 1, and you do follow-through. I am interested to see how running without a heat exchanger will work. The miata motor is VERY knock prone under 3krpm, fueling has to be really dialed in down there, but you can still run decent timing.

technicalninja

Warpspeed, your setup is bad assed.
But, if you turned the AC compressor 90 degrees to mount it (it looks that way) you will eat compressors with great regularity.
The way these puppies oil is critical to have the suction and discharge port clocked very close to original angle (usually into the compressor from the top).
It's very similar to the oil path clocking for the turbocharger.
I own a shop that specializes in Automotive HVAC systems, I do a bit of everything but HVAC is how I feed my family...

I'm 56 years old, you are my elder...
If you were like me (first engine and transmission build at 14 years old) then you could have been wrenching longer than I have been breathing...
This give you MORE experience than me hence the "respect your elders" comment.
When I have time I'd like to further the discussion regarding compounding turbo/supercharger but in another thread.

Pat's thread is his own. He post enough interesting stuff that it is the only thread I stay "subscribed" too

Warpspeed

Thank you Mr Ninja,
I did a bit of HVAC many years ago, but really know absolutely nothing about swash plate compressors.
I just assumed they were kind of round with all the cylinders pretty much the same, and the whole mess was just splash lubricated inside.
Not really into airconditioning for my Miata anyway, the climate here is fairly mild its not really needed.
I included an aircon compressor in the mock up build just for the sake of completeness, and to leave my future options open.

Ted, its great to hear from another happy compound convert .
I know of several very successful compound builds, and in every case the owner has been absolutely thrilled with the results and would never go back to just a supercharger or just a turbo ever again.
These also tend to last over time. Far too many high power turbo builds have very short lives.

All the compound builds I know of have been road cars but one.
The race car is used for hill climbs in Scotland, and its a light weight Mitubishi EVO with a TVS1320 and TO4Z turbo. It makes an easy and very reliable 800+ Hp at the wheels.
It regularly takes out fastest time of the day, and hold class records almost everywhere it races. He is regularly faster up the hill than some of the open wheel race cars !!
Its a fast machine, 0 to 100 Mph in 4.6 seconds, but he says he can also pull away strongly in fifth gear from just walking speed.
Its definitely not a narrow band peaky dyno queen. He says its so easy to drive compared to just the TO4Z he started out with. Its actually road registered too, but says its far too dangerous to drive on the street.
He was inspired by one of my threads on the Engineers Forum to build his own compound, and we have been great friends ever since.

Definitely agree with Ted that roots and TVS superchargers make much better candidates for a compound, for the reasons he states.
The required pressure ratios are low, and when bypassed they generate almost no extra heat, and consume negligible crank power.
Supercharges have come a very long way in recent years, mainly through the R&D by Eaton and money from Ford, and the TVS is the pick of the bunch.
They have now been around for long enough on production cars that they can now be picked up secondhand relatively cheaply.

With both turbos and superchargers, the latest technology is always the thing to go for if you have a choice.

patsmx5

iTrader: (16)

Bump!

Been busy at my new shop, so haven't had time to work on my car.

But, I am planning to put a motor together soon to have a BU engine that I will then probably swap into the car to have a new fresh motor. Then probably rebuild the old one to have a spare.

I have a block, crank, and stock VVT head.

I have a set of new forged rods I plan to use.

Need to buy everything else.

My general thoughts are: high comp, very strong, ready for 50 psi boost.

So, now the hard part, what to put in the new motor? Thoughts welcomed.

technicalninja

Your ingenuity is ALL you need...

What is a "BU" engine?

technicalninja

Might look into "Pulse detonation" engines.

You could solve the problems Pat.

good2go

iTrader: (2)

Back Up

Ted75zcar

iTrader: (2)

I would ditch the VVT. I suspect it will be more trouble than it is worth for you.

patsmx5

iTrader: (16)

I already ordered a set of VVT cams, but now that you say this, I'm already thinking you may be right. Bad thing is, I had an excellent 99 head I sold about a year ago and kept my spare vvt....

I need to look into cams available for the non-vvt and then keep an eye out for a 99 head in good shape.

Dr.Sep

You can also just run the VVT head without VVT hooked up

technicalninja

VVT makes camshaft selection a buttload more critical on an interference engine.
I was watching a maximum effort S62 engine build on one of the M5 forums.
They were building a S62 for boost and decided to add "cams".
The world class machine shop that was building it normally builds race engine in which the VVT is disabled.(BMW calls this system "Vanos").
Because "street car" they left it active and on the engine dyno it bent the valves during initial testing...
The bent valves ruined the pistons, a pair of max effort ported heads, AND one the the valves hit the side of a cylinder wall and took a "chunk" out.
Ruined a max effort block as well.
Only thing left was the rotating assembly.
40K plus worth of damage...
The machine shop paid for EVERYTHING but would not continue without de-activating Vanos.

On a non-interference Miata build this will not happen but???

I am a believer in being able to alter cam timing and the dynamic compression with VVT. It does really help.
It adds 200% more complexity to the valve train and it doesn't help 200% in regards to the power. Maybe 10-15% down low.
Its biggest "gain" in a FI system is a reduction in spool time IMO, you NEED this Pat!

I would check valve to piston clearance at both ends of the VVT range before using on a BP with either bigger valves, custom pistons, or more than stock lift. Camshaft duration does not matter.
.080 on intake, .100 on exhaust is safe in my book...

Pat, I would EXPECT you to use VVT on your build. You're just that type of guy...
I will on mine.

For this check you will need a bad VVT actuator to modify with locks at either end of the range.
If you can't scrounge one up in Houston I will send you one for modification and testing. I have a bad one.
I will want it back after you are finished but you can have it as long as you need it.
Having you modify it will mean I don't have to...

Ted75zcar

iTrader: (2)

Yeah, if you get anywhere near the seat pressure the numbers call for at 50psi, I believe the actuator will become too weak to control the angle. For reference, I have tuned 2 setups with ST heavy doubles and the hold duty is ~80% on both of them with hot oil, they also both have a max effective DC of ~85%.

Leafy

iTrader: (1)

And you get really fun effects when your vvt actuator is totally overwhelmed. Like if you have low oil pressure. Like something that sounds and looks like valve float on the dyno as you start to try and move the VVT off of full retard.

Pat running that kind of boost I wouldn't even consider a high compression engine on E85. Maybe if you plan to use methanol for your primary fuel. Unless maybe you're going to run massive cams to bleed off that extra static compression.

technicalninja

Pat's moving to the dark side, real dark...
Looks like he's gonna run diesel!
One of my AC customers has a diesel repair shop.
Mac's Performance (macsdieselperformance.com)
They hotrod the crap out of them.
How about 3 turbos, both parallel and sequential. Chop 1/3 of the head off to allow for individual intake runners, Custom TIG welded SS intake manifold and more than 100 PSI!

Yeah, I saw the "high compression and 50 psi" and if it wasn't Pat I wouldn't believe it.
I wanna watch him try...

Nitromethane might work under those conditions but the BP head and head studs will NOT (with currently available parts).

Thank you Ted75zcar. I never thought about serious valve spring effect on the VVT actuator. A nice viewpoint!
It's nice to have but if it cannot be controlled it's a detriment...

Warpspeed

A thought experiment for you Pat....
Everything that goes through a positive displacement supercharger, MUST also go through the engine.
Moving the inlet valve timing back and forth is going to have absolutely minimal effect with a PD blower.

Normally aspirated or turbo engines are a very different beast.

Newaza

You may want to do a 1/2 or 3/4 fill on the block. Also cut ring head gasket or since you have the big bucks you can go all in and do o-ring HG setup. That's the plan for my next build anyways.
https://www.summitracing.com/parts/h...YaAgAEEALw_wcB

patsmx5

iTrader: (16)

Update time!

Been busy at my shop working on other cars, but I have made a couple purchases for the miata and been thinking over what I want to build next.

So far for the motor, I have rods, and I ordered a radium fuel rail, and i ordered the HG Newaza recommended above. Plan to order some other internals soon.

I also made another big purchase..... A used FFS kit!

Anyone who's followed this thread knows where this is about to go... Compound boost V2.0!

I'm still working out what this next setup is going to turn into.

For example, I'm set on running it as compound boost, at least at first, to see how that works. I may try bypassing the SC down the road too so I can A-B test that and see what works best under different circumstances.

I plan to keep the turbo manifold I have now. I plan to keep the EFR turbo for now and see how it works with this setup. Probably keep my existing intercooler so I don't have too many things to change to get this up and going.

It looks like the SC has a pair of injectors in the manifold post-sc for charge cooling. I may use them, but I'm more tempted to put some fuel on the inlet of the blower for more even distribution and cooling. Either E85 or methanol.

As for why the FFS? Well, it's not perfect, but it has several benefits. I can buy it and bolt it on and it works. I don't have to fabricate and design much. I've been so busy that if I didn't buy this, then a compound boost setup would not be in the cards for quite a while. So this gets me compound boosted immediately.

Another benefit, I get to learn about how this type of setup works, before designing my own down the road. So lets me gain some insight and real world experience before designing my own setup. That is well worth the cost of the FFS. Not mention, if I do sell the FFS down the road, their resell value is pretty good.

SC supposed to arrive Tuesday!

curly

iTrader: (25)

As far as I saw, there were a lot of inefficiencies with the FFS plenum, and the 5th injector didn't seem to do any cooling. Try to smooth out the inlets inside the plenum, run your AIT post blower, and see if you can get a charge cooler shoved in the plenum, or add meth. Or nitrous.

Leafy

iTrader: (1)

Have a look at the monster truck diesel dyno videos that old guy has been making. Seems like compounding turbo though a blower isnt very efficient.