[sapl]

Originally Posted by Twinn

Thanks Mate, If i ever get a chance to catch you folks during the raids or INRC events (if at all they come up) I would definitely be interested in looking at the girdle

Now to the main:

1.What would be the RPM increase in this build?
2.What would be the exact RPM at which the turbo would start engaging?
3.Would you also port the cylinder heads for this build? If yes do you reposition the intake and exhaust ports or not?

Mate maybe these are really dumb questions, but please adjust

Hi

Those questions don't appear dumb to me !

You are welcome to drop in any time.

As for your queries,

1. We are not going to raise the rev limiter in this application.

2. This turbo should begin to kick in at 1800 rpm and develop good boost at 2500rpm. This is an estimate. We will know the exact numbers when we tune the vehicle on the dyno.

3. For this project we are not porting or polishing, since this is not for competition use. The upper part of the engine is bone stock - no modifications whatsoever.

Some progress today - the hood and the scoop have arrived after painting. We went in for a 2-tone scheme for the scoop. The photo shows the hood and scoop just placed on top - not fixed.



The second pic shows the oil take-off for the turbo from the engine block.

[Twinn]

Originally Posted by sapl

1. We are not going to raise the rev limiter in this application.

So how is the BHP increased without the RPM increase? So this gypsy is going to stay stock 6700 rpm at redline?

Originally Posted by sapl

Some progress today - the hood and the scoop have arrived after painting. We went in for a 2-tone scheme for the scoop. The photo shows the hood and scoop just placed on top - not fixed.

Looks great, will the engine be needing more oil, as the turbo is also utilizing the oil?

[sapl]

Originally Posted by Twinn

So how is the BHP increased without the RPM increase? So this gypsy is going to stay stock 6700 rpm at redline?

Looks great, will the engine be needing more oil, as the turbo is also utilizing the oil?

The bhp will be increased by boosting the pressure of the air going into the engine. Yes, the engine will remain at the stock rev limiter. If we need to increase the rev limit it is essential to change engine internals.

The engine will not need any additional oil, although there will be a small increase (a few ml) because of some oil that will stay in the lines.

In case this was for a competition application or high boost, then an oil cooler would be necessary.

The purpose of this project is to make a simple upgrade without too much of intrusion into the engine, and meant primarily for regular road use.

This is quite different from a serious performance upgrade which is used for continuous hard use.

[Anil Rajani]

Looks good!!! Quick question... how do u think the drivability is going to turn out?? the stock engine is a delight at high revs but thats not what exactly makes for fun driving in a gypsy!

[Pal]

Greetings sapl!

Firstly, i am hooked onto this thread. Its neat, small and you're providing some good detailed pics (turbo lubrication system). Keep providing some more pics mate.

I do believe you are into this professionally, so may I ask what kind of calculations you did for this entire project? I mean cost is just one thing. I am interested into the engineering paperwork you may have scribbled. Or is this based on 'observe and learn' technique from other examples?
By the way, I have no clue how well does a petrol engine-turbo charger marriage function (or any other marriage for that matter :P) Ive just dealt with diesel engines most of my career! So if you could throw a little light on that subject?

Wishing you the best! Looking forward to see it shape up!

P.s.- while reading the write-up, i had the same set of questions as Twinn-and no sir, they're not dumb!

[sapl]

@Anil - the drivability will certainly be better. The car will have that extra punch when you press thhe throttle - anyway, will give you a real feedback once the car gets on the road.

Originally Posted by Pal

Greetings sapl!

Firstly, i am hooked onto this thread. Its neat, small and you're providing some good detailed pics (turbo lubrication system). Keep providing some more pics mate.

I do believe you are into this professionally, so may I ask what kind of calculations you did for this entire project? I mean cost is just one thing. I am interested into the engineering paperwork you may have scribbled. Or is this based on 'observe and learn' technique from other examples?
By the way, I have no clue how well does a petrol engine-turbo charger marriage function (or any other marriage for that matter :P) Ive just dealt with diesel engines most of my career! So if you could throw a little light on that subject?

Wishing you the best! Looking forward to see it shape up!

Thanks Pal

Will keep 'em coming !

No, we do not do things by trial and error.

As far as the technical math is concerned, for a target power of 120 bhp, we need to get approximately 50% more air into the engine (stock is 80bhp). This is accomplished by the turbo. With enhanced air going into the engine, it is important to feed the required fuel also. Insufficient fuel will make the engine run lean and can destroy it.

The turbo in effect pressurises the air going into the engine by hanrnessing some of the wasted energy from the exhaust. It is important that we control the pressure (or "boost"). The conventional and simplest way of controlling is by means of a wastegate, which bypasses a par tof the exhaust away from the turbo. However this methods typicall opens gradually and therefore suffers from a slow build of boost, which reflects as "lag".

In order to minimise this, we employ electronic boost control and open the wasstegate after the required boost is achieved. This gives us a much better torque curve.

The additional fuel required will be fed from an extra injector mounted upstream of the intake manifold.

In our design, we do not disturb the original ecu in any way. We add the Unichip piggyback ecu which will do the boost control and the extra injector control and the ignition timing.

At any point of time, if we remove the turbo and the extra injector, the car reverts to its stock condition.

There are some fundamental differences in the way we do fuelling for diesel and petrol engines. Diesel engines are typically lean burn engines, whereas petrol engines can be badly damaged by lean conditions. That is the reason that boost control is critical in a petrol engine.

[abhijitl]

Very interesting project. Although I have an old Gypsy (MG410), I am keen to know what gains are you able to achieve on completion of the project.
Best of Luck for further planned mods

[sapl]

Most of the fabrication work completed ! Started the engine today.

A view of the general arrangement



The sequential blow off valve



The extra injector



A view of the turbocharger assembly



The down pipe



A front view with the scoop mounted (Grill yet to be fixed)



A video of the blow off valve working

Turbo Maruti Gypsy blow off valve - YouTube

Started the engine - idles well. We have to complete the extra injector wiring, finish Unichip wiring, install Unichip turbo module, install boost control solenoid.

This will be followed by dyno tuning - should be done in the next few days.

[binz]

Hey, great build .. congrats!

I have a question though, is there a particular reason you opted for an extra injector instead of bumping up the fuel pressure/baleno injectors etc?

[sapl]

Originally Posted by binz

Hey, great build .. congrats!

I have a question though, is there a particular reason you opted for an extra injector instead of bumping up the fuel pressure/baleno injectors etc?

Thanks Binz.

The reason why we have chosen to keep the original fuel system completely intact is to have the additional fuelling come into play only when needed (boost comes on). In fact, if the turbo hose is removed, the car will revert to the stock mode. This increases the dependability of the installation. If we had gone in for higher pressures or bigger injectors (which we did for the Raid de Himalaya Gypsy), then the entire management system becomes modified. (Please remember that we do not disturb the oem ecu in any way - we only use the Unichip piggyback to supplement it when needed).

Also, an upstream injector helps atomise the fuel better, and the charge air gets some additional cooling from the evaporation of the fuel. Thus the fuel air mixture becomes more homogenous and is also additionally cooled - both extremely desirable consequences. (You would have see the "shower head" injector positioning on some of the big bikes - they do exactly that.

[abhijitl]

Any suspension straightening or mods to avoid torque steer?

[sapl]

Originally Posted by abhijitl

Any suspension straightening or mods to avoid torque steer?

We do not foresee torque steer to be an issue with rear wheel drive vehicles. If it were a front wheel drive vehicle then yes, we might have had to do something.

[Twinn]

Holy Moly!!! I am learning way too much in this thread Your explanations are very detailed buddy. maybe you should open up a course on these for the gearheads like us, alternate career (if you have the time to spare )

Originally Posted by sapl

No, we do not do things by trial and error.
As far as the technical math is concerned, for a target power of 120 bhp, we need to get approximately 50% more air into the engine (stock is 80bhp). This is accomplished by the turbo. With enhanced air going into the engine, it is important to feed the required fuel also. Insufficient fuel will make the engine run lean and can destroy it.

Why not 25% fuel and 25% more air? How effective is this theory than remapping the ECU to gain the power. I understand it would not harness 120 bhp at a go, but would remapping at-least increase it to 100bhp?

Originally Posted by sapl

The turbo in effect pressurizes the air going into the engine by harnessing some of the wasted energy from the exhaust. It is important that we control the pressure (or "boost").

I got lost here, what do you mean by harnessing the wasted energy from the exhaust?

Buddy from where did you procure the parts?
Also another question which is the simplest and the best effective method to increase the power for a gypsy? I mean the 1.3 carb version..

I hope you have a excellent run on the dyno, Good luck mate!!!

[sapl]

Originally Posted by Twinn

Holy Moly!!! I am learning way too much in this thread Your explanations are very detailed buddy. maybe you should open up a course on these for the gearheads like us, alternate career (if you have the time to spare )

Why not 25% fuel and 25% more air? How effective is this theory than remapping the ECU to gain the power. I understand it would not harness 120 bhp at a go, but would remapping at-least increase it to 100bhp?

I got lost here, what do you mean by harnessing the wasted energy from the exhaust?

Buddy from where did you procure the parts?
Also another question which is the simplest and the best effective method to increase the power for a gypsy? I mean the 1.3 carb version..

I hope you have a excellent run on the dyno, Good luck mate!!!

Hi Twinn

In fact one thing on our wish list is to open an academy for performance tuning ! We would be glad to have you as our student !

Yes, 25% more air + 25% more fuel will theoretically give you 25% more power.

However such simple equations are stymied by other laws that come into play. The Air Fuel Ratio on forced induction engines is slightly different than naturally aspirated engines. The change depends on a number of factors such as size of engine, original compression ratio, boost pressure etc. Hence when we increase air by 25%, the fuel will not necessarily increased by 25% exactly. Most of the cases it would be more.

The other issue is, how do you exactly meter 25% more air ? Fuel is easy - the injector can be controlled by changing its timing (provided it has some spare capacity left) or fuel pressure increased, or a combination of both. Once you have reached the capacity limit of the injector, you need to either go for bigger injectors, or (as we have done) add an additional injector, assuming your engine management system is capable of handling that.

Also, the problem is that boost will not be uniform throughout the rpm or load conditions of the engine, so there has to be a means of dynamically controlling the boost.

Increasing fuel pressure means that the fuelling will increase at all conditions.

Hence it is imperative that you have an intelligent system which controls how much air is going into the engine and simultaneously increases or decreases fuel as desired by the tuner.

A lot of energy is wasted in an engine in many ways - heat through the cooling system, friction, and the kinetic energy (heat + speed) of the exhaust gases. A typical internal combustion engine harnesses only around 35 to 40% of the total energy in the fuel as useful power at the output of the crankshaft. The gases coming out of the exhaust are at very high temperature and at very high speeds.

What the turbocharger does is to run a turbine (very similar to a pinwheel which is driven by the wind) using these hot and fast gases. On the same shaft as the turbine, there is a blower which forces air into the engine.

So a part of the energy that is wasted as heat and fast gases going out of the exhaust are recycled into driving a blower to force more air into the engine. Since the unit combines a turbine and a charger (blower), it is called a turbocharger. Simple isn't it ?

We have procured the parts from a variety of source. The turbocharger was configured to our specifications by the manufacturer.

For a carb engine, porting & polishing of the cylinder head, adding a good exhaust system and a good camshaft would give you good results.

If you want to go extreme beyond that, then you should think of switching to injection and either fitting a turbocharger or a supercharger.

Hope this is useful !

And yes - thanks for the wishes !

[wanderernomad]

This is a good build and obviously you guys know what you are doing. But maybe I can add a few stupid questions of my own:
1. The need?
2. The cost?