All the nissan/datsun engines!!

[MegaGTS4]

Stumbled across this on the net the other day!

http://www.geocities.com/MotorCity/Pit/382...23/engines.html

And in there they metioned the MA09-ERT 930cc OHC 3 cylinder, 6 valve, turbo and supercharged, EFI 110hp,aparently a micra engine! probably quick too!!, I didn't know that nissan made a supercharger and turbo combo but I knew that toyota experimented with this principal too (toyota crown if I remmeber correctly!)

My question is:

What advantages would this setup have over a standard supercharger or turbo setup?

Can anyone help?

MEGA

[funkymonkey]

MA09-ERT is a single overhead cam engine, not DOHC like the RB20/25/26's, CA18's n SR20's. I did some research on superchargers and I found out that to have a turbo/supercharger setup you'd need to control where one cut off and the other kicked in, since the turbo is a linear boost and the supercharger is an exponential boost, its very very difficult to do, althoguh it has been done. I remember I was wiped off the face of the earth in my 180sx by a super-turbo Suzuki Swift or sumfin.

Superchargers are constantly boosting as they are belt driven, so the moment you get the engine runnign you are boosting. Turbochargers need to spool, because they are run by exhaust gasses that the engine generates. In other words the supercharger boosts where the turbo charger dosen't, by combining the two, what happens is that you get more air being pressurised into the engine for higher combustion rates.

The problem is that since "efficient" superchargers are exponential in boosting (eg they start with 2psi and end up with 16 psi at max RPM) they peak at the same time turbo chargers do, and since the only way to get around this is to either cut off the supercharger at a predetermined time or to lower the psi of the supercharger (easy solution) unfortunately by the time you've lowered it enough to balance it out, you've decreased low RPM boost to almost that of a turbo only set up that it makes no sense to put a supercharger in.

... werd ...

[Warpspeed]

I have actually had a dual system fitted to my 4WD laser at one stage of its development. It is the quickest combination I have ever had. It was only removed because the supercharger eventually became noisy from internal wear, and was probably not far from spitting the dummy.

I also wanted to try something a bit different. My next attempt was to fit a variable vane turbo, as these are supposed to have really good low speed boost characteristics and fast response. This is still on the car at the moment. The supercharger/turbo combination just eats it.

Still not satisfied, my current project is a supercharged 33GTS-4, although I am still looking for a suitable car in Melbourne. I may import one though if I still cannot find one by Christmas.

Trust me guys, the supercharger/turbo combination on a road car is an absollute killer. The only down side is cost and fitting it all into the available space. I could talk for hours on this subject, but the Skyline may finally end up this way as well, time will tell.

[funkymonkey]

hehe I wanted to do the same thing, just to have something different. I heard the Toyota Supercharger SC14 off the 1G-GZE engine (2.0L Straight 6) will work with my engine pretty well, so maybe a turbo/supercharger is in order in a couple of years.

Making the manifold for this combination will be a pain though.

Warp... would you go roots, centrifugal or screw type in combination with a turbo?

[Warpspeed]

The idea of adding a supercharger is to get low end boost, so forget the centrifugal. I used a Toyota roots blower from a 1GGZE plus a TO3 from a VG30 fitted with a 0.82 exhaust housing. The wastegate setting was 18psi, and an intercooler was used as well. The blower drive ratio was 1.5:1 on a 1.6 litre engine, and the blower gave around 9psi by itself, the turbo did the rest.

I had full boost from 2000RPM to redline, the thing pulled like a train at any speed, there was absolutely no turbo lag either. The thing is, that when you stomp on it the blower produces instantaneous boost, and the sudden large increase in exhaust flow really kicks the turbo into boost quickly as well.

Set the desired boost with the wastegate, then play around with the blower pulleys and turbine exhaust A/R to get the effect you want. The blower gives low end grunt, the turbo top end airflow, you can set it up to have more of one or the other, or both!

You can have all the advantages of either method together, with none of the disadvantages. Absolutely fantastic ! ! ! It is a lot of work fabricating parts though. If you can do it all yourself no worries. If you have to pay a workshop to make the bits and sort it all out, then the expense would be HUGE.

[MegaGTS4]

Thanks Warpspeed and funkymonkey for the info!!(most interesting!!)

Found another car that used turbo and supercharger the famous lancia delta s4 group B rally car!!

http://tucars24.valuehost.ru/1985_lancia_delta_s4.htm

(interesting stuff, let me know what you think!!)

MEGA

P.s Warpspeed check your pm's!

[Warpspeed]

It sounds like we have similar interests !

I have been turbocharging, supercharging, and twincharging engines for thirty years (I am an old bugger). It is the engineering that interests me, figuring things out, and trying new ideas. You mentioned the GTS-4 gearbox. As far as I know these are identical to the GTR, at least with the RB25. I think the RB20 version has different ratios though.

My plan is to put RB26 crank, rods, and pistons into the RB25 block, I already have these parts. I can keep the same engine number and avoid any hastles with the cops that way.

I also already have the GTR six throttle body inlet manifold and GTR intercooler.

I do not want to buy a GTR, even though I could afford one (just). The 33GTS-4 has everything I want at half the price, and without the big wheels, wings, and badges that attract the wrong attention. The 33GTS-4 looks like a family car, not a hotrod, this is absolutely perfect for a sleeper.

Cheers, Tony.

[MegaGTS4]

I'am doing the same thing(almost) but my intentions are to drop in a rb26dett and GTR gearbox into r32 gts-4 and get something close to the GTR but at half the price!!

Just curious on how you managed to synchronize the turbo and supercharger set up on your laser?

(still waiting for my importer to call with the news that he has found a worthy front cut as the last one fell off a forklift before I could pick it up!!)

As for the gearbox this thread might help explain it better!!

http://forums.skylinesdownunder.co.nz/show...=exact+gtr+gts4

[Warpspeed]

I thought of a front cut myself, but decided it would be cost less and more convenient to just buy exactly the bits I needed. I really have nowhere to keep it, and selling the surplus bits to recover costs is a real pain. Your situation is different though.

o/k Mega, how to supercharge AND turbocharge your engine:

I will first describe the simple system, then the problems with this, and the extra complexity required to fix ALL these problems.

The basic flowpath is, cold air intake, filter box, airfowmeter, throttle body, turbo compressor, supercharger, intercooler, intake plenum, engine, exhaust turbine/wastegate. The wastegate reference pressure comes direct from the intake plenum.

The positive displacement supercharger pulley ratio is set to give boost at maybe half the desired final boost, therefore the turbo controlled by the wastegate sets the final boost figure. The turbo makes up the difference between supercharger boost and desired final boost level.

Note that the throttle body must be moved to the intake side of the supercharger. Otherwise with a positive displacement supercharger, if the throttle body is on the outlet the pressure will rise to infinity if you close the throttle at high RPM. At best you will blow off an intercooler hose, at worst explode the intercooler, or break a drive belt.

All decent positive displacement supercharger systems are fitted with a bypass around the blower. Every car manufacturer fits one, and so should you, for a road car anyway. One problem with moving the throttle body to the blower inlet is that at part throttle the blower is sucking like crazy against an almost closed throttle plate.

The engine will be running at vacuum under steady state constant speed cruise, the vacuum behind the throttle plate will be far higher than manifold vacuum. The blower is actually doing a fair bit of work as a vacuum pump, and draws crankshaft power. It also runs hot, and creates noise, as well as increasing fuel consumption by maybe 10%.

The thing to use as a blower bypass is an external turbocharger wastegate. Good ones have a pressure connection on each side of the actuator diaphragm. Fitted with a 3psi (boost) spring, the diaghpram will open the wastgate at a differential pressure of 3psi, equal to about 5 inches Hg vacuum.

The wastegate is fitted onto the blower discharge and when open feeds back into the turbo inlet. The wastegate doubles as a blower bypass and turbo blowoff valve,I will return to this later.

A second problem arises from moving the throttle body to the blower inlet. All of the pipework after the blower, plus the intercooler add to the plenum volume. The plenum volume now becomes very large, and when you suddenly close the throttle, the engine becomes slow to lose RPM. It feels a bit peculiar actually, as though the engine has a one ton flywheel attatched. This reduction in throttle response really slows down gear changes and spoils the drivability.

Stick with me guys, this is where the story gets a bit strange.

The fix is to have two throttle bodies one on the blower inlet, and a second one in the original position back on the plenum. Both operate simultaneously, and as I will explain synchronisation is not in the least bit critical.

On my car there is provision for an auto kickdown cable, as well as the standard throttle cable. I simply used two throttle cables, one to each throttle body. Simple.

A pair of hoses connect the blower bypass wastegate control diagphram directly across the throttle body fitted to the plenum. The vacuum across the plenum throttle body holds the blower bypass open.

How it all works:

At idle, the idle screw on the plenum throttle body controls the idle speed, and any fast idle features built in also work normally. The idle vacuum holds the blower bypass open, meaning that the blower rotors just circulate air around through the open bypass. The throttle body in front of the blower is just cracked open, how far is not really important because the second throttle body on the plenum controls the airflow. Pressure in the intercooler is atmospheric, or very nearly so (just like a stock turbo engine).

Light throttle and gentle acceleration, there will still be greater than 5 inches Hg vacuum and the blower bypass is still held fully open. The blower intake throttle body opens in sync but there is no boost because the bypass remains open.

You can drive around like this all day, no boost, keep up with the traffic, and the fuel economy is stock.

More throttle opening and the pressure drop across the plenum throttle body falls, allowing the spring to close the blower bypass. The action is very smooth, boost increases as the bypass closes, and off you go under boost. This is unbelievebly smooth in operation, drivability is excellent.

At full throttle, boost pressure appears equally on both sides of the blower bypass diaghpram. As it only responds to differential pressure, the increasing boost has no effect on the bypass.

Both throttle bodies open together, but if the fully open position does not exactly coincide, it does not really matter. So setting up the two throttle positions is in no way a critical adjustmet.

At redline you slam the throttle shut for a gearchange. The blower bypass opens unloading the supercharger, and acting as a turbo blowoff at the same time. The throttle at the blower inlet closes almost fully. There is no boost spike.

It all sounds a bit strange I know, but print this out and have a long think about it all. It is the result of eighteen months worth of development time. It works superbly, and is easy and non critical to get going.

The only thing to watch is the selection of the spring in the blower bypass wastegate. The spring must be heavy enough so that the wastegate will not be forced off its seat by maximum boost pressure. If it is too heavy the vacuum requird to hold the bypass open will be very high, meaning boost will come in early at very light throttle openings.

For maximum fuel economy you want to be able to keep up with the traffic with reasonable throttle openings without hitting boost. You want boost upstream of the plenum throttle body to begin at perhaps 80% throttle, not 20% throttle.

Hint. For best control characteristics the blower bypass wastegate should have a large diaphragm area, compared to the

area of the poppet valve. This makes spring selection less critical.

This post is waaaaaay too long, sorry.