Supercharging potential for K10...

[pietro]

I noticed that my alternator on my 1988 model micra has a cooling fan connected to it (some of the later model K10's do not have this).

As the rpm picks up it really does displace quite a bit of air, so much so that I believe it could be modified for forced induction to improve VE and perhaps add a couple of BHP?

If some sort of casing could be made to surround the fan whilst not effecting anthing else I am sure that the air produced could be funneled into the carb inlet! See where I am going! Anyone been here before?

Ideas suggestions please... we may have found a cheap route to supercharging! If someone could design and build a DIY fitment for the car they could sell a shed load!

 

[Ed]

I noticed that my alternator on my 1988 model micra has a cooling fan connected to it (some of the later model K10's do not have this).

Yes they do, but they are internal not external.

As the rpm picks up it really does displace quite a bit of air, so much so that I believe it could be modified for forced induction to improve VE and perhaps add a couple of BHP?

No not really, it does move air but NOTHING like what would be needed to make any difference

If some sort of casing could be made to surround the fan whilst not effecting anthing else I am sure that the air produced could be funneled into the carb inlet! See where I am going! Anyone been here before?

Ideas suggestions please... we may have found a cheap route to supercharging! If someone could design and build a DIY fitment for the car they could sell a shed load!

The fans are very basic and are only capable of cooling the alternator, nothing more I'm afriad.

 

[AMY]

Each cylinder displaces around 250cc per revolution, therefor if your 1 litre engine is consuming 1 litre of air per revolution imagine how much that equates to at 5 thousand rpm. To gain a positive intake charge your compressor (be it a turbo or supercharger etc) will need to create more air than your engine is using as efficiently as possible. This is way beyond anything that spins to compress air at the same speed as your engine turns, this is why turbo's spin at around 100,000 rpm.
I suppose you could direct some air flow towards the air filter, but this air is already warm from cooling the alternator, your best bet would be to get a length of tube and run it from the front of the car directly to the air filter housing.
Or fit a turbo or supercharger !!!

Amy

 

[SammoHung]

AMY: What are the most signifficant benefits of having a constant supply of COOL air?

Cheers

 

[AMY]

cool air = power + efficiency

Running a cold air feed to your air filter is going to provide a constant stream of cold air.
At the moment your engine draws air from under the bonnet which is much warmer than the ambient temperature. The amount of power an engine can make is dependant on the amount of fuel and air it can combust, if the air is cooler it is denser therefor more air can be crammed into each cylinder which = more power. Think of it this way, many of the cars that race at pikes peak Colorado start with around 900hp by the time they have reached the summit (14,110 feet) the power has reduced to around 600hp. This is because the air is less dense at altitude so the engine is less efficient.
So bringing this back to the micra, you aren't going to notice anything significant but a cold air feed is going to help.
Have you ever noticed your car feels crisper on a cold winters morning? this is the same sort of thing.

Cheers
Amy

 

[Ed]

Each cylinder displaces around 250cc per revolution, therefor if your 1 litre engine is consuming 1 litre of air per revolution imagine how much that equates to at 5 thousand rpm.

Not quite right! a 4 stroke engine needs two revolutions to complete a full cycle. So 1.0 micra will displace 0.5l in a rotation on a 1.0l

To gain a positive intake charge your compressor (be it a turbo or supercharger etc) will need to create more air than your engine is using as efficiently as possible. This is way beyond anything that spins to compress air at the same speed as your engine turns, this is why turbo's spin at around 100,000 rpm.

Not true for most roots type positive displacement superchargers. The one on my march ST is probably 1 engine to 1.5 turns s/c at a guess. It is however true for all turbine based turbo/superchargers.

I suppose you could direct some air flow towards the air filter, but this air is already warm from cooling the alternator, your best bet would be to get a length of tube and run it from the front of the car directly to the air filter housing.
Or fit a turbo or supercharger !!!

Amy

Agree!!!!!!

Ed

 

[Ed]

cool air = power + efficiency

Running a cold air feed to your air filter is going to provide a constant stream of cold air.
At the moment your engine draws air from under the bonnet which is much warmer than the ambient temperature. The amount of power an engine can make is dependant on the amount of fuel and air it can combust, if the air is cooler it is denser therefor more air can be crammed into each cylinder which = more power. Think of it this way, many of the cars that race at pikes peak Colorado start with around 900hp by the time they have reached the summit (14,110 feet) the power has reduced to around 600hp. This is because the air is less dense at altitude so the engine is less efficient.
So bringing this back to the micra, you aren't going to notice anything significant but a cold air feed is going to help.
Have you ever noticed your car feels crisper on a cold winters morning? this is the same sort of thing.

Cheers
Amy

Bear in mind that carb'ed cars cannot ajust for dense air. If WOT fueling is already on the lean ish side (13:1) then more dense air can actually give less power but be nearer stoitch. (14.7:1). MAF sensors in fuel injected cars can account for air density, so they will make more power in cool dense air.

 

[AMY]

'Not quite right! a 4 stroke engine needs two revolutions to complete a full cycle. So 1.0 micra will displace 0.5l in a rotation on a 1.0l'


Ok, point taken, I should have said cycle not revolution, as one revolution is used expelling the spent exhaust gasses.

'Not true for most roots type positive displacement superchargers. The one on my march ST is probably 1 engine to 1.5 turns s/c at a guess. It is however true for all turbine based turbo/superchargers.'

Like you say, the pulley on the s/c is underdriven so it rotates faster than the engine anyway. I'm not familiar with roots superchargers but the basic principal of a supercharger is that the impeller spins at speeds far greater than 5-6k rpm? My point was that a fan being driven directly from the engine will never supply enough air!

'Bear in mind that carb'ed cars cannot ajust for dense air. If WOT fueling is already on the lean ish side (13:1) then more dense air can actually give less power but be nearer stoitch. (14.7:1). MAF sensors in fuel injected cars can account for air density, so they will make more power in cool dense air.'

Agree, but I'd rather have a cold air feed than not. The difference it makes to afr is negligable on a car like the k10. Agree?

You don't mis anything do you Ed!!!
lol
Amy

 

[SammoHung]

Cheers guys!

Some interesting info there from you both (and the banter was good too!)

lol...Armed with my new found knowledge in air density and air to fuel ratios at wide open throttle, I've just thought of a great new mod involving an old fridge freezer, a second hand gear box and a fan! (joke).

Here' another one....(serious this time)...My air filter housing has a manual valve for taking hot or 'normal' air either from under a collector plate around the exhaust manifold or from under the bonnet as usual (marked 'summer' and 'winter'). What circumstances would hot(er) air intake be an advantage.

I see the that the fuel injected cars have an automatic valve here (very P.O.S.H)

Cheers,

 

[AMY]

Hi Sammohung,

As far as I'm aware the only purpose of the valve is to draw warmer air into the intake in cold weather to improve driveability. In extreme cases the fuel can actually freeze within the carb but I am yet to hear of this happening on a micra. As mentioned previously during warmer months the cooler air is more beneficial.

Cheers
Amy

 

[Ed]

'Not true for most roots type positive displacement superchargers. The one on my march ST is probably 1 engine to 1.5 turns s/c at a guess. It is however true for all turbine based turbo/superchargers.'

Like you say, the pulley on the s/c is underdriven so it rotates faster than the engine anyway. I'm not familiar with roots superchargers but the basic principal of a supercharger is that the impeller spins at speeds far greater than 5-6k rpm? My point was that a fan being driven directly from the engine will never supply enough air!

Roots type positive displacment 'vane' and more recently twisted vane superchargers are what most people think of when they hear of supercharger. The recent 'planet drive' superchargers with the turbo style compressor housing are in my eyes not a true charger Check this out though, they really dont spin that fast.. http://www.automotive.eaton.com/product/engine_controls/superchargers/M45.asp this is the data for the mini cooper S charger.

'Bear in mind that carb'ed cars cannot ajust for dense air. If WOT fueling is already on the lean ish side (13:1) then more dense air can actually give less power but be nearer stoitch. (14.7:1). MAF sensors in fuel injected cars can account for air density, so they will make more power in cool dense air.'

Agree, but I'd rather have a cold air feed than not. The difference it makes to afr is negligable on a car like the k10. Agree?

You don't mis anything do you Ed!!!
lol
Amy

Definately agree. I've always wondered (and have never looked into) how air density affects car drag and peformance..
Nice to have another techy on board btw

Ed

 

[Ed]

Here' another one....(serious this time)...My air filter housing has a manual valve for taking hot or 'normal' air either from under a collector plate around the exhaust manifold or from under the bonnet as usual (marked 'summer' and 'winter'). What circumstances would hot(er) air intake be an advantage.

I see the that the fuel injected cars have an automatic valve here (very P.O.S.H)

Cheers,

I have been in a K10 and experienced carb icing. It had a K&N induction kit on it. Other than that never, and it is rare. However injection cars really dont need it as they dont have a venturi (where the ice normally forms) and so chances of anything icing up (including throttle body) are very very small. However you do often still get intake manifold heating, where water is routed around to heat the intake manifold. Seems a crazy idea, but the idea behind this is to stop fuel condensing on the intake manifold. Again a very odd idea since the injectors are so close the engines that this should never be an issue. I suspect this is more of an emissions thing.

Ed

 

[sketch]

So do you both agree that it would be benificial -and possible - to supercharge a k10.
If you say that the bmw mini supercharger doesnt spin as fast. Then would this not be better for the k10 (as standard) especially for testing purposes!

Would be kool to see that.

Also how would you both recommend adding a supercharger to a k10?

Metal headgasket? etc

cheers
Some nice info coming from you both

 

[AMY]

Ed: Cheers

Sketch, I'm sure it would be beneficial to supercharge a micra, and a lot easier than turboing. Some things to consider would be,
1. the rotation of the S/C firstly, as it would need to be run off a pulley on the offside.
2. then flow rates, A supercharger designed for a larger engine will probably provide too much boost.
3. Space would also need to be a consideration,
4. as would fabricating a pulley and a way of tensioning the drive belt.
5. Fuelling and spark advance would need to be addressed if you were going to make enough boost to make the project worthwhile.
6. You would most likely need to lower your compression and fit a stronger H/G.
7. Then you might find that the gearbox clutch etc aren't up to the extra power.
8. The outlets on superchargers are often an irregular shape, so you would need to fabricate a section to join it to the intercooler/intake.

Saying that cooper s super chargers are 10 a penny on ebay, and if you were going to run low boost you could probably scrub a few of the above points.

Best ask Ed for more advice, i'm more of a turbo man myself.

PS: Ed is the ST or figaro H/G interchangeable onto a regular k10?

Cheers
Amy

 

[sketch]

Well you can get copper h/g stamped quite cheaply. or possibly use a double/triple layer gasket?

Was considering since u can then fit a nice thick set R5GTT intercooler, run it at say 6-7 psi.
Since some k10 came with Power steering (rare i know) but some also have the bracket to the rear of the engine. this could then be simply added by using a primera power steering pulley!
It is also very easy to get a certain length of belt to drive it!

There is loads of space under a k10 bonnet. them engines are tiny. LOL

Since the early model k11 clutch fits the k10 that must mean that it will be possible to even get away with putting a ga16 Gearbox aswell! along with the clutch etc.

May well be a nice project that.



What do you recommend regarding the flow rates, also what you recomend for the fuelling!
No ECU to just dump a controller in there

Cheers

 

[AMY]

Good thinking sketch, If you are having a copper gasket made up you would be able to specify it thicker than original, therfor lowering the compression rate.

I wouldn't recommend using an R5 intercooler, they have plastic end tanks and a stupid flappy thing to limit flow. But there are plenty of intercoolers out there in scrap yards.

I'm not sure what carb you could use, perhaps one of an r5, but i'm not sure how well it will run a 1L car, i'm sure it would with a bit of fiddling and smaller jets.

You would have to get a selection of pulleys to get the boost level you require trial and error I suppose.

As for spark advance you may be able to use stiffer springs in the vacuum advance to give a slower/lesser degree of advance.

Cheers

Amy

 

[SammoHung]

Make way for the novice here...!

Why copper? what's the standard material and more common material alternatives?

How much would a costomised Cu head gasket like this cost? (tooling etc?)

This is starting to get pretty detailed now..lol

......Or have I had one too many Skol Super?


Cheers,

 

[AMY]

Sammohung:

As a material copper is fairly maleable and quite strong, so it seals quite well and can take a lot of pressure. The downside to this is that if your head and block surfaces are not completely flat it will leak, because unlike a regular gasket it can't deform enough to fill defects on the head or block. Lots of modern turbo cars are coming out of the factory with metal gaskets as standard because if applied correctly they are much more reliable, stronger.
I'm not entirely sure what standard gaskets are made of it's usually a kind of card type stuff with metal rings around any points of pressure, eg cylinders and oilways.
The most up to date performance gaskets are usually multi layered laminated types, they are usually made of three layers of steel coated with a sealant this allows for a good seal against the mating surfaces but allows some movement when the head and block expand and contract. I have recently fitted a HKS unit to one of my GT4's and it cost almost £200, when you compare that to about £15 for a standard gasket you either really want one or you really need one!

Cheers

Amy

 

[sketch]

Just so happen to have an MA12 thats just had a head reskimmed. Sure i could deviate away from getting it standard running again. and have a play about.

Just need a donor car to dump it into at the end of it.

 

[sketch]

just to add that he metal multi layered gaskets also give a good variation as manufacturers say it best to UP the thickness if a head has been reskimmed.

Opel (vauxhall) are prone to this.

they also have 4 different gradiant of ther gaskets for this cause aswell. Difference being able to tell due to a marking in bottom corner. normally has 4 options ( no holes -1 hole on left - 1 hole on right - 2 holes out)

The metal better cos the alloy heads dont half like to expand when they get hot.
This normally causes the slight metal linings of the standard gaskets to cause lips around the pots. Not good when trying to seal from water getting past.

I think this might just have to get tried.

 

[Ed]

Lots to reply to here:
sketch, Supercharging a 1.0 K10 is the best bet. using a thicker headgasket is far from ideal. It upsets the squish area on the pistons. If going for cheap option then yeah sure, stick a thicker one in there and see how it goes.

AMY:
The SC roation should be fine, there is nothing different to the way the K10 engine turns, its the same as almost every other engine out there. You would definately need a boost bypass, some have them built in other wise as you close the throttle to change gear, or stop accelerating etc, you get high boost pressures on the back of the throttle body and this inturn puts alot of load on the supercharger. If you put a bypass on it set at a sensible level it avoids this.
There is plenty of room around the K10. My st has the supercharger behind the engine near the oil filter, however it would be hard to get one here using a roots blower, not specifically designed for the purpose. Belt tensioners are not hard just design a bracket which pivots and do it in the same or similar way to the alternator. Fueling would be a major concern. HOWEVER i think the hitarchi is an internally sealed carb, in which case with a rising rate carb pressure regulator, it should cope with boost to a certain level. This would need to be experimented with. To keep costs down I would simply retard the distributor and make a more elegent solution later if the project was worth while. The other problems would just need some simple problem solving.

Sketch, see above for fueling ideas. It would be VITAL to get a wideband readout just to see what is going on, but pressuring the hitarchi carb with some mods should work.

AMY, copper headgaskets are also very easy to make with water cutters etc. So they are ideal for one offs etc. I cannot knock the standard non metal hg that the St uses however. It has withheld upto 1.6 bar on a regular basis and more recently peaks of around 1.8-9!

Dont S/C the 1.2. They have much thinner bores and generally have a problem with headgaskets standard, let alone with mods.

Ed

 

[sketch]

were is best place to get a wideband readout.

Was looking at the ma12 last night and it has bracket holes already to the back of the engine bay (powersteering location) So making an adfaptor plate for this would be very easy. that way you could then simply just trial and error all size of pulleys from any were.

Amy: the R5gtt intercooler i have has been "rapped" to be able to cope up to 24psi of boost, so i think it would be plenty, for testing purposes at least, and will fit rather snug behind the "splash" panel in front of the alternator/side of radiator.

ED: what would be the best option to you to do regarding the pressure release. If the S/c didnt have one of these?
Im gonna use a BMW MINI one as they are a penny a piece, and very easy to get hold of. especially for testing. could be quite cheap to set up.

Ill ive the double layered gasket a try first.. see if it copes etc. then if not move onto getting a copper gasket cut me thinks.

What would be your estimates from the results of te S/c on a k10. ed?

 

[crogthomas]

HOWEVER i think the hitarchi is an internally sealed carb, in which case with a rising rate carb pressure regulator, it should cope with boost to a certain level. This would need to be experimented with.

Ed

If its any help, I had a K10 carb apart on the bench the other night and it did indeed seem to be entirely sealed. For example the float bowl vents into the carb throat via that big (4-5mm dia) 'pipe' level with the choke plate.

 

[crogthomas]

what would be the best option to you to do regarding the pressure release. If the S/c didnt have one of these?
?

A turbocharger dump valve does exactly the same thing. Job jobbed.

 

[Ed]

sketch, just search the net for wideband fuel monitors. They are farily expensive. R5 intercoolers are still horrid, and seeing as you can get so many for near to nothing why bother. You need a recirc ajustale dumpvalve/blow off valve, thats set to a low pressure around say 6 psi. This would possibly be the tricky part. Double layered headgasket sounds like a waste of time, I would be surprised if this sealed and if so if it lasts longer than a few days. If you ran 6psi and had it set up quite well i would expect around 25% increase in power and torque.

 

[SammoHung]

Thanks for the info AGAIN guys...

WOW! card with metal rings!.that was a surprise i suspected either one or the other bot not both in the same gasket....

cheers

 

[zeon]

chance to catch up with the vw polo, did it year's ago. zeon.