Supercharging book is complete, Finally!

[Greg Gordon]

Hi Chris,
Your project is one of the most exciting on this board, probably the most exciting in a technical sense (for those of who who have not seen it, Chris is building a Lancia Stratos replica with a supercharged 3 liter Alfa V6).

I wouldn't worry too much about the pipes being too big, especially over shorter distances or with curves. This is even less of a problem in your application since you have plenty of supercharger capacity. For reference I used a 3" pipe on a 2.5 with only 7 pounds of boost from an MP62. That's technically way to big, but if you do the math it really only cost something like 5 horsepower.

Is your kit a "Devil's Own" system. I have not seen one in person, although I think they are pretty good. All of the kits out there are similar, however "Coolingmist" seems to be staying a few steps ahead of everyone else.

Greg

[CorseChris]

Morning Greg,

Given my rate of progress, I think I'd have to call it interesting rather than exciting Kind of you to say so though!

Mm, I'm probably not too far off with the air pipes then. That's encouraging.

It is a Devils Own kit I got. It looked to have the right pump and other bits, and it was relatively cheap, despite the usual £1=$1 exchange rate that we end up with. Further to your thoughts, I'll be needing a few accessories to go with it now, but considering I 'designed' this setup without considering water injection, the penalty isn't too painful.

With the benfit of 20-20 hindsight, I think I'd have been better to go with my original idea, which was to retain the 164 plenum totally stock and fit the charge cooler in-line between the blower and the plenum. Unfortunately, I was wedded to the notion of using the Jaguar cooler core I had, so ended up with grafting it into a cut-down 164 plenum as there was simply nowhere else it could go. After I'd gone down this path, I discovered that I could get a compact and allegedly effective cooler for about $450. Still a fair bit more than what this cooler setup has cost, but probably better in a number of ways. Ah well, I'll try what I have and if it fails, I can always revert to a stock plenum and adapt the setup for an in-line cooler....or just possibly do away with it and rely on the water injection??

Still, see what I've got first before planning what to do when it fails. Never know, it might just work brilliantly.

I'll sort out some shots of the components this afternoon and post them up. I'll put them on the thread I started way back and link from here for sanity.

Cheers

[CorseChris]

Some more here;

12V V6 on aftermarket ECU

I'll try and keep it all in the one place now. Sorry, I've been spreading it all over the shop!

It kind of fits in at least 2 categories, but I'll stick with the one I started in the ECU section unless anyone has any particular objection or feeling either way.

[Greg Gordon]

I will follow the Statos project on that other thread.

Thanks to everyone who bought my book. I have received a lot, of compliments which means a lot to me. I did put a tremendous effort into writing this book. I am going to start selling it on evil bay and submit it to a publisher. I don't know if I will be able to do anything other than self publishing because of the book's heavy bias towards Italian cars.

Greg

[MALDI]

Greg, I understand from your book that water injection is not a form of chemical intercooling (it does not cool the charge nor appreciably increase its density) but instead it prevents knock so that higher levels of boost can be used without detonation.

Question: How does it work? Water will displace fuel and oxygen in the intake charge and reduce the power output proportionally; therefore, the amount of extra boost achievable must more than make up for the dilution of the intake charge with a compound (water) that is neither fuel nor oxidizer. (Would nitrogen (N2) injection do the same thing?) You are not leaning out the charge from 12.5:1 with water injection but instead diluting the entire charge with a "spectator" gas. (Air is of course mostly the spectator gas nitrogen (N2) with other spectators like carbon dioxide.)

[MALDI]

I found some useful information from a patent application (Internal Combustion Engine, US 60/854,914 27.10.2006, Kirk R. Collier, Jr. inventor). (NB: The main goal of the invention is to reduce NOx emissions.) He states:

"Common methods of diluting the charge include the addition of excess air to the air-fuel mixture charged to the combustion chamber to operate under "lean-burn" conditions, the use of exhaust gas recirculation (EGR), water injection, or combinations of the three. The term "excess air" is intended to mean an amount of air in excess of the stoichiometric amount necessary to support complete combustion of the fuel. The use of charge dilution results in an increase in the heat capacity of the gases used in the combustion process. The increase in heat capacity in turn reduces the peak temperature of the combustion process. By sufficiently reducing the peak temperature, NOx emissions can be significantly reduced. One problem with operating an engine at high charge dilution is that for some fuels, the charge mixture can become too lean to support complete combustion, resulting in a "misfire" condition. Misfire not only results in a severe drop in engine efficiency, but also results in high emissions of unburned hydrocarbons in the engine exhaust."

So then, the question becomes, How do you detect and eliminate misfire? How much water is just enough?

[Greg Gordon]

Hi Maldi,

It would seem that water vapor takes up space that could be used by fuel and air. Indeed, increasing humidity does decrease air density. However the decrease is minor and partially made up for by the slight amount of cooling prior to the combustion chamber. In other words air density remains about the same up to a point.

The chart on page 44 does a good job of showing just how much power (and thus density) will decrease when you add water. As you can see in that chart, the drop in power is more due to an increase in total liquid. Take a look at the results with an air fuel ratio of 12.5:1, power drops off very little, however with and AFR of 10:1 it starts to really drop off as you increase the amount of water.

How does water reduce the tendancy to knock? It does it by cooling INSIDE the combustion chamber when the liquid changes state into a gas during the compression stroke.


I don't know anything about injection nitrogen. Water seems pretty effective to me.

How much water is enough. That's sort of like asking how much octane do you need. It depends on a lot of things. Page 51, point 9 represents the maximum amount of water that should be used with a 12.5:1 afr. This is reflected in the charts on pages 44 and 50. In many cases you can use less.

Greg

[craigdp]

How would supercharging work with a 164 S ? The same 3.0 liter engine but with higher compression and running a front wheel drive machine...
I'm considering re-building my engine and I wonder if I should think about this option.

[Greg Gordon]

Hi Craig,

Supercharging a 164 is difficult, but not impossible. If I were to do it, I would probably place the supercharger on the driver's side of the motor, near the front of the engine bay and drive it with a long driveshaft. That's about the best way I can see to do it. This method is quite common, various kits for the Acura NSX do it that way, so does the TRD kit for the Scion TC.

Supercharging a 164 would be a pain, I would probably consider turbocharging it simply because the parts to do that already exist, as it was offered that way from the factory.

With "S" pistons I would keep the boost down to 5-6 psi and run water injection. In general I am scared of cast pistons on a forced induction motor, and really suggest forged units. That also allows the use of non-interference pistons greatly mitigating the single biggest risk to these engines, timing belt/tensioner issues.

Now, that said, I have run 10psi non intercooled on my GTV6 with success, but I had a good water injection system and I was careful.

Greg

[CorseChris]

I've seen a few smaller Alfa's having Eatons fitted over here - the layouts are similar to the 164 (but usually tighter for space). The most common method seems to be to junk the A/C compressor and locate the blower in that space. Not an option I'd have gone for myself as I like my A/C, but it does have some merits.

I did contemplate a long driveshaft arrangement on my installation as it would have solved a good few issues...but there wasn't any more room at the other end of the engine really so i opted for my least-worst choice.

[Greg Gordon]

I don't really like the idea of ditching the A/C compressor either.

In the case of your Stratos, just getting the Alfa V6 in there is pretty impressive. Finding room for A/C, a supercharger, and an intercooler took some real creativity. Your supercharger mounting system is something I have never seen nor thought of!

Greg

[CorseChris]

I'm certainly running out of space back there! I still need to find homes for the WI tank & pump, cooler pump & header plus yet more plumbing & wiring....starting to get desperate for hiding places now Somtimes long for the days when it had a Lancia TC motor in there.....

At one point I very briefly thought about using the 'front' cam to drive the blower, but quickly dismissed that notion. A long shaft would work well on the 164 I think. Not simple to do though.

[braddo]

Greg,
Congratulations on getting the book finished (and published yourself). So now that you have lots of time on your hands, will you be looking into offering a supercharger kit for the alfa Twin Spark and/or Nord ?

The idea of being able to bolt on a kit to a standard engine like you have managed with the V6 is just soooo appealing!! Do you think a similar outcome is possible for the TS with standard Motronic injection?

Apologies if you have answered this elsewhere...

Best regards,
Brad

[Greg Gordon]

Hi Brad,


A supercharged Nord will be done soon. The motor is in my dad's Milano right now, and will be doing its test run later this year. Its test run will be from Oklahoma to California, to Toronto Canada, to D.C. and back! The Milano Nord and Spider kits will be almost identical.

There is a possibility of a supercharged twin spark within the next year. However it's only a 50/50 chance. The supercharged Nord is a certainty, it's in the shop now.

For those who don't want to wait, or who want to make a kit on their own, my book should give them all the information they need.

Greg,
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[braddo]

Good to know, Greg! I guess the Nord kit will use (for mild applications) jetronic as per s3 or s4 spider for the fuelling, right? I have a '72 GTV (in the UK so on carbs) so would have to change to some sort of fuel injection anyway, and I presume using the factory FI will be the most cost effective method for what I want.

Brad