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Supercharged V6 - anyone tried water injection?


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Big block V8 guys that have roots blowers very similar to what are on the Lotus supercharged cars run spacers right after the blower and inlet manifold in which they create a water injection hole to s

Where is that video link? 

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15 minutes ago, Swiss380Cup said:

@cib24 what bothers me is that I never came across someone who installed it on a Lotus.... anybody out there can comment on that ??? The supercharged engine has been here in the Exige for quite some time now.... why is that..

I will dig up old info. The Americans have done it plenty of times on the older S2 Exiges that were imported legally over there. 

I think the reason it hasn't been done on the S3 is that it's not sold to the Americans (lol) and the type of people that buy these cars don't tend to like to get their hands dirty so to speak. They like speed, performance driving, etc. but don't like getting under the car and changing their oil, etc. They just pay Lotus or someone to do it. And they aren't into modifying. :stuart: Gotta have all of those Lotus service history stamps for resale value you know!

Not that I blame them really!

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@cib24 you’re right about that .... americans are all over muscle cars and injecting stuff being methanol, nitro, you name it... not into european culture but I’ll talk to my jap car fan friend or my mechanic at Mercedes dealership ... he has a tuned Evo or Sub and he must know... I’ll drop by tomorrow

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@cib24 Unfortunately, installing water injection on the 2GR with SC isn’t as straight forward as it might have been on your RX7. 

The water pipe has to be installed after the SC (otherwise it might lead to premature wear of the SC). Because the SC essentially connects directly to the inlet manifold, there isn’t anywhere to fit an adaptor plate. So the ali manifold will have to be drilled. It is possible but certainly not easily reversible. 

Also, the OEM ECU wouldn’t be able to handle separate maps for water on and water off. So, it would also require an aftermarket ECU. Something, I suspect, that most owners wouldn’t be willing to change. 

 

PS FWIW, I’m still looking into it. ?

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Alright, let me provide some insight.

First, no there is no problem injecting prior to the supercharger. If you have good atomisation from a good water injection nozzle then you end up with a nice mist which evaporates almost immediately and is exactly what you want. If you have a faulty nozzle or not a water injection specific one then you might be injecting water like a hose and that would lead to huge droplets which isn't ideal.

Water can be injected pre-supecharger just fine. Millions of people do it and have no issues.

https://prometh.com/blogs/tech/72804675-can-i-spray-water-methanol-injection-through-my-eaton-supercharger

Distilled water (which is all you should run, never tap water) will have no effect on the supercharger blades or coatings. The water atomises and basically evaporates as it comes into contact with the massive rush of air from the intake.

The best place to locate it on a Exige is where the brown patterned circle is and it will be absolutely fine because you have a decent distance from the injection point to the actual supercharger so the mist will atomise and mix with the incoming air very nicely.

And if you look here, Snow Performance sells kits for the Evora S and 400:

https://www.snowperformance.eu/en/water-injection/boost-cooler/lotus-evora-3-5-400-298-kw-117729

Water on S2 Exiges and Elises:

http://www.lotustalk.com/forums/f160/installed-water-meth-injection-my-sc-elise-108770/

http://www.lotustalk.com/forums/f25/aem-water-injection-methanol-install-359385/

Now beyond that let's talk about the OEM ECU and how water works.

Water is not a fuel. It will not alter the ECU map. Water only cools the intake charge. Colder air is denser, and the supercharger will therefore compress more air because it is more dense. This will result in more power. Now, that does not mean you will make more power on the OEM ECU. What it means is that because colder air which is more dense is being fed into the supercharger the ECU knows the air is cold (like going out for a drive tonight when it's only 5C) and thus will inject more fuel and advance timing for more efficient and more powerful combustion than if the incoming air was hotter and less dense. When the air is hot and less dense then the ECU has to compensate by retarding timing and injecting less fuel which means you will have less efficient combustion and less power.

All the water does in this instance is ensure that your ECU is optimising combustion by allowing denser air to enter the motor and be compressed by the pistons for more BOOM and thus power.

If you were injecting methanol that is a different story because methanol is a fuel and does require special tuning.

Back onto the subject of water and now let's focus on using it to make more power with an aftermarket tune. As I said, water cools the intake air and makes it more dense. More dense = better and more efficient combustion = more power. Well, when you put a smaller pulley on the supercharger to increase power like Komotec does then you end up with more heat because the supercharger is working harder to compress a larger amount of air. Heat = power loss. Therefore, you can use water with a smaller pulley or an aftermarket tune which advances timing and optimises fueling (leans it out compared to the OEM ECU which runs rich) in order to offset the increased heat you would normally see from running more boost or higher ignition advance.

It does not take a lot of water to have a dramatic effect on cooling intake and subsequently exhaust temperatures which means with water you have a much larger margin of error and it helps increase the life and reliability of your ancillary components like your supercharger, catalytic converters, ignition system, etc. simply because the engine will be running near its most efficient at all times when you are driving it hard.

Looking at my car as an example. Despite running high boost on my factory twin turbos (which when stock are already pretty much heaters as they generate tons of heat), I am able to cool my intake air that goes into the motor from 55-60 C to 30-35 C with the smallest water injection nozzle in the AEM kit. The 250 cc/min nozzle (the kit also comes with 500 cc/min and 1,000 cc/min nozzles) and the benefit of using the smallest one is that it atomises the most efficient since it is injecting the smallest amount of water at WOT. With my intake temps only sitting at 30-35 C my intake charge is denser and my ECU injects more fuel and thus my motor compresses more air and the explosion from the spark is larger and I make more power.

Remember, distilled water will not harm your supercharger. It evaporates pretty much instantly since it is injected as such a fine mist.

Water is not a fuel so it does not mess up your ECU map and you won't be injecting enough to cause wonky issues that can occur when injecting more than 1,000 cc/min on drag cars.

Water keeps your engine operating near its peak efficiency when being driven hard and your ancillary components appreciate it due to less heat.

Water is your best friend and you should buy a kit and install it and see for yourself. Don't make me buy an Exige Sport 350 and show you myself!

:P

 

 

 

20299_Exige-V6-Cup-engine-banner_717x300.jpg

maxresdefault.jpg

Edited by cib24
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  • 2 weeks later...
On 14-11-2017 at 22:47, cib24 said:

 

The best place to locate it on a Exige is where the brown patterned circle is and it will be absolutely fine because you have a decent distance from the injection point to the actual supercharger so the mist will atomise and mix with the incoming air very nicely.

 

Now, that does not mean you will make more power on the OEM ECU. What it means is that because colder air which is more dense is being fed into the supercharger the ECU knows the air is cold (like going out for a drive tonight when it's only 5C) and thus will inject more fuel and advance timing for more efficient and more powerful combustion than if the incoming air was hotter and less dense. When the air is hot and less dense then the ECU has to compensate by retarding timing and injecting less fuel which means you will have less efficient combustion and less power.

Hi Roy,

 

really reading this topic with much interest!  Just a question on my side though: you mention the ideal place for the nozzle is on the brown patterned circle.  This is after the MAF.

 

So how, as per your quote, does the ECU know that the air is colder as the "cooling" takes place after the MAF?? Afaik there is not pre charger intake temp measurement anymore after the MAF.

My guess is that the lambda post combustion will read a leaner AFR as expected/calculated from the ECU table for a given intake temp and the car will throw a CEL.  Or are you saying that due to leaner AFR, the ECU will adjust by injecting more fuel (hence raising HP) but ignoring the thresholds set in the table for that given intake temp (which measures higher than the actual temp due to the water cooling post MAF)?

 

I must say, all very interesting :):)

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@cib24 Unfortunately, installing water injection on the 2GR with SC isn’t as straight forward as it might have been on your RX7. 

The water pipe has to be installed after the SC (otherwise it might lead to premature wear of the SC). Because the SC essentially connects directly to the inlet manifold, there isn’t anywhere to fit an adaptor plate. So the ali manifold will have to be drilled. It is possible but certainly not easily reversible. 

Also, the OEM ECU wouldn’t be able to handle separate maps for water on and water off. So, it would also require an aftermarket ECU. Something, I suspect, that most owners wouldn’t be willing to change. '

 

Actually, not true at all. You can certainly inject the atomised water before the SC. It produces no problems at all.

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  • 3 months later...

Left field thought if I may, for the engines with charge coolers keeping the coolant in the system cold is by a radiator, no new news there. Something to think about, a friend who is A/C specialist, rigged a second evaporator into the intake of his V8 Holden, and got an extra 50kws at the rear wheels on a 30c day. The improved cooling of the charge cooler would be interesting. Only hang up is in very cold environments you will have intake icing on the throttle body, so a temp control system would be needed ask any light aircraft pilot about this issue.

any way just an idea, carry on...

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Effectively what he did was use the A/C to chill the air intake to supply the engine with at approx 2 to 5 c.

my thinking is that temp to be supplied the the charge cooler radiator coolant.. as I said a left field thought.

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The objective is to improve the efficiency of the charge cooler, even water sprayed on the cooler radiator will help especially in hot climates, only issue is corrosion.

in Hot climates, Ferrari use the return a/c line to cool the fuel before it goes to the injectors, it’s a similar idea that I recon lotus could use, even running the charge cooler line next to the chilled condensed, A/C line to the evaporator would assist.

 

107C60B3-5593-458C-8914-B4F67BD37E4D.png

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  • 2 months later...
On 04/12/2017 at 12:25, Breeze said:

@cib24 Unfortunately, installing water injection on the 2GR with SC isn’t as straight forward as it might have been on your RX7. 

The water pipe has to be installed after the SC (otherwise it might lead to premature wear of the SC). Because the SC essentially connects directly to the inlet manifold, there isn’t anywhere to fit an adaptor plate. So the ali manifold will have to be drilled. It is possible but certainly not easily reversible. 

Also, the OEM ECU wouldn’t be able to handle separate maps for water on and water off. So, it would also require an aftermarket ECU. Something, I suspect, that most owners wouldn’t be willing to change. '

 

Actually, not true at all. You can certainly inject the atomised water before the SC. It produces no problems at all.

Bravo,

You don't need to install the water pipe post supercharger. You install it pre-supercharger and pre-throttle body. The blower will be fine. You are injecting a super fine mist and US muscle car guys have been injecting water pre-throttle body into their Eaton/Roots blowers since the 1960s. Also, remember, old school carbureted cars have the carb before the blower which means they are injecting fuel and air pre-blower so liquid is going into the blades and it causes no problems. 

1513.jpg

 

So, there won't be any premature wear to the blower and it's not worth worrying about. 

An example, the AEM Water Injection Kit comes with three nozzles: 250cc/min, 500cc/min and 1000cc/min. I use 250cc/min on my FD-RX7 although I could probably benefit from 500cc/min in the summer when it's 30C outside and I'm doing a track day as it would cool the air quicker. Anyway, 250cc/min is probably all you need given the Lotus Exige/Evora supercharged V6 doesn't run that much boost, and it's not enough water to mess with the OEM ECU map in any way. Besides, the Lotus ECU is much more advanced than what is on my RX-7 (which is a nearly 30 year old ECU technology) so it would be able to compensate anyhow. 

The point of the water as I said above is to keep the air charge cool and thus ensure you don't lose power due to heatsoak and your ECU can keep the air/fuel, ignition, etc. trims in the optimal part of the OEM ECU map so you get all 345hp all the time. 

https://www.ebay.co.uk/p/AEM-Water-Methanol-Injection-Kit-1-Gallon-3-8l-V2-P-n-30-3300/1843501496?iid=332508220602&chn=ps&adgroupid=51456964475&rlsatarget=pla-404030386252&abcId=1130086&adtype=pla&merchantid=9802104&poi=&googleloc=9045997&device=c&campaignid=1029031424&crdt=0

Stock photo

 

This is also way cheaper at £400 for a water injection kit than buying a Komotech Chargecooler setup. 

Edited by cib24
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  • 3 months later...

A question…Does the water injection system only inject when the supercharge is boosting, or does it inject all the time. I’d presume that the controller would be connected to the MAP sensor and only inject when a positive  boost pressure is detected.  

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  • 2 weeks later...

Martin, the systems mentioned in this thread - and all I have looked at recently - have its own MAP sensor and injects at a certain pressure. Som with a fix rate, the more sophisticated with a proportional flow rate. Personally I would prefer to control it with temperature instead.

I exported some data logging from the standard ECU from two trackdays with very different weather conditions and the MAF difference is huge, even though the engine configuration is the same. Let's see when I have time to summarize and post it.

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  • 5 weeks later...

The point mentioned but seems to be forgotten in all this is the tuning and the boost/fuel. The point of water isn't just to cool combustion. Water massively increases the anti- knock value of the fuel. It allows vastly more boost and timing. If you simply inject water, you'll lose power. The S cars aren't really in danger of knock with more timing, so the water won't help there. The water gets interesting by running, say, 12-15 psi boost on that motor with standard pump gas. You can't do that with a 1320 and probably not with the 1700 from Lotus in the 400 cars. Maybe we can do that on the 1900 charge cooled powerhead, but we haven't pushed that marriage so far to see what the blower does in that range. 

-Phil

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  • 2 months later...
On 23/11/2018 at 15:48, turbophil said:

The point mentioned but seems to be forgotten in all this is the tuning and the boost/fuel. The point of water isn't just to cool combustion. Water massively increases the anti- knock value of the fuel. It allows vastly more boost and timing. If you simply inject water, you'll lose power. The S cars aren't really in danger of knock with more timing, so the water won't help there. The water gets interesting by running, say, 12-15 psi boost on that motor with standard pump gas. You can't do that with a 1320 and probably not with the 1700 from Lotus in the 400 cars. Maybe we can do that on the 1900 charge cooled powerhead, but we haven't pushed that marriage so far to see what the blower does in that range. 

-Phil

Phil, I’m interested in your post above. I’m thinking of having a TVS1900 ( not charge cooled ) fitted to my 2015 Evora S. I was thinking of fitting either the AEM or Snow Performance water injection system at the same time. Do you think the water injection would be of value on the TVS 1900 installation?

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1 hour ago, Breeze said:

Phil, I’m interested in your post above. I’m thinking of having a TVS1900 ( not charge cooled ) fitted to my 2015 Evora S. I was thinking of fitting either the AEM or Snow Performance water injection system at the same time. Do you think the water injection would be of value on the TVS 1900 installation?

Hi there,

It could if you bump up the boost and increase the timing to take advantage of it. If all you do is add water without boost and timing, you will lose power.

So you'll need some blower pulleys, a tuning interface, and a dyno to get it sorted...

-Phil

 

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  • 6 months later...

Hi guys, i wanted to revive this thread.

I have a 380 sport and live in a country where it is unfortunately 95 degrees ambient with 100% humidity. Ive tracked the car a couple of times and its rather clear from the terminal speeds on the straights that the car is making alot less power than on paper...i would even guess its as low as 280bhp under such conditions.

I know most of you are of the opinion that installing it pre supercharger is adequate. But may i ask how much more effective the system will be post...and are the injectors designed to operate under boost pressure?  I must admit i worry that a poor installation post supercharger may also bring about issues with reliability. 

 

Thanks in advance

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Lifted from another forum:

Quote:
Originally posted:
Has nobody consider aquamist or similar kit? I have a PA CC setup on mine but a lot of improvements could be made.



We've done some work with aquamist [and similar] kits on various supercharged engines.
The best initial results come from pre-supercharger as it improves the seal between the screws BUT it can cause mechanical issues where you effectively reduce the spacing between the screws... 

Installation POST supercharger works well but on the Lotus application the SC blows into a lower inlet and getting even spread across all 6 cylinders is difficult.

The other issue is when the factory ECU has been re-tuned to compensate for the water/meth mixture and the water/meth stops injecting.... the factory ECU does not then re-compensate as it's effectively "blind" and you run the risk of causing damage to the motor.

We have a strategy to control Water/Meth injection with full safe-guards and fuel/ignition compensations that is included in the standard firmware package for the Lotus Exige/Evora range.

—————————————-

Further to that reply..... if the water injection is only water, and not a water/methanol mix, presumably it does not interfere with the ECU. It would be no different to driving the car in very humid conditions, the ECU should easily be able to cope with the variation in inlet humidity and temperature. Most water injection systems are/can be, preset to inject only at when the manifold air pressure reaches a certain point, ie, when the blower goes into boost. Water injection seems to be very common in the USA but much less so in Europe, though I see that some of the BMW M3’s use a water injection system on turbo motors. I’ve often thought water injection is a good solution for a non charge cooled supercharged car that is used mainly as a road car.

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Effectively injecting pure water, direct port is pretty much the only way to achieve this, will lead to massive power loss if ignition timing is not advanced considerably. Water mist delays initial flame front development and reduces flame speed. 
Once you start advancing ignition timing, it really becomes alive. This is all given you were heavily knock limited in first place. 

Running a 50/50 methanol water mix by weight (or about 60/40 by volume) will reduce this flame front speed issue, but not eliminate it. And you may need to remove fuel. Although will also run pig rich and knock resistant given your spark is strong enough. 

If you inject into or just after the supercharger, you mostly cool metal, but not the air. As now air temperature hardly drops, you end with less partial pressure of oxygen than before -> power loss.
You want all the evaporation happening in the cylinder. 

The methanol will still burn and do its thing, but any bigger water droplets or steam will pass straight trough the engine into the exhaust in liquid form, combustion or not. This will also render the water useless. This is IMHO the reason so many have better success with very high methanol content mixes or even pure methanol. It does not have to enter the engine in form of a mist in order to increase knock resistance. 
Bevor one starts to cite WW2 engines. the americans used direct port injection with a jet bar right in front of the inlet port of each cylinder. The germans used to inject directly into the cylinder.

I went through various iteration with my supercharged Rover K at the time. It worked really well.

My conclusion to get the most out of it:
Use direct port injection with a jet right before the fuel injector and on the same side as the fuel injectors. 
Avoid any turns the mist has to take. Any curved plenum runners won't work. They are not designed for wet flow and will turn your mist into a stream of water from centrifugal forces. Guess how water is removed from natural gas? Let it takes turns at high speed 🙂
Injecting into a plenum has litte effect unless you use a lot of methanol.
The more you inject, the more it does until you cannot ignite it anymore or you hit MBT without knock.
If you inject so litte it does not require retuning, it does not do anything. 
You need to have fail safety, best two systems such as flow metering and extremely fast knock control.

 

@calibratedperformance should be able to add more to the discussion. 

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