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Oh and I installed the knock sensor - its a 3 wire Bosch wideband sensor meant for a VW (Golf I think). Reason I chose this sensor is the normal 2 pin Bosch plug would collide with my coolant reroute pipe.
This sensor is prewired with a remote plug, and this allows me to *just' fit it with a low profile bolt between the block and coolant pipe. I helicoiled the block down from the M10x1.25 down to the M8x1.25 of the new bolt - which actually did not require any drilling or retapping! Just wound the helicoil in to the existing thread - I'm used to getting kicked in the nuts by seemingly simple jobs turning out to be nightmares so I will take that! There's about 2mm clearance but this should be enough. The pipe is soft mounted with a P clip at the cambelt end, but the torque reaction of the engine under acceleration will move the pipe away from the sensor rather than towards it. I bought a knock sensor filter box, it will provide a digital knock / no knock signal to my MS2. It has adjustable sensitivity and will probably take a bit of setting up. I am also going to install a headphone jack in the car that is linked to the knock sensor so I can plug in a headphone amplifier and headphones for tuning purposes.
There is space between that bolt and pipe, honest
I also forgot to mention I made a new driver side (in the UK) engine mount. If you have seen Curborough Sprint Course video you will notice the gearstick is having a bit of a wild ride. I was running the upgraded motorsport rubber engine mounts, they are still in one piece but I noticed that the back plate, particularly on the drivers side has been rounded over a bit and is probably what was allowing the engine to move around a bit more than I would like. I also noticed that the engine / supercharger was sitting at a bit of an angle (supercharger side low) so the new mount will correct that too. All that torque!
I have taken inspiration from the various performance engine mount options out there and adapted the stock engine bracket to accept a Superpro front wishbone bushing that I had to make a 'hybrid' setup, leaving the upgraded stock style engine mount on the exhaust side. I measured the shore hardness of the Superpro at 70A with a durometer tester which I think will be ok for a road / track dual duty car. If its not I have another softer option but we will see. The subframe side of the mount is just a bit of box section cut up a bit to form a U bracket.
While having variable water injection is an elegant approach, I would not be too concerned with doing it.
In reality, the injection pump has a significantly varying pressure, so you are going to get different flow rates as the pressure fluctuates, unless you add a FPR and a return line for the water.
Also, with the supercharger you have, if you inject more water/meth than required, it just means you are going to have to refill the tank more often. I don't think it will change your resulting HP/TQ.
Maybe others have input on this.
If you look at this AEM video, you can see the pulsing flow at 15:11 into the video. Among other things, in this video they are comparing the advantages of their new v3 nozzles that have better atomization and use less
fluid than the V2 nozzles. The only advantages they cite are quicker time to lower temps, and less fluid usage.
While having variable water injection is an elegant approach, I would not be too concerned with doing it.
In reality, the injection pump has a significantly varying pressure, so you are going to get different flow rates as the pressure fluctuates, unless you add a FPR and a return line for the water.
The pump is a recirculating type, set to 200psi so in many respects it is like the dead head fuel system found on the nb miatas. There will be pressure losses along the pipework from the tank in the rear to the nozzles in the front but if the pump is any good and the supply voltage stable this should be consistent. The benefit of PWMing (is that a word?) a valve rather than a pump is I can control the flow rate without dropping the pressure at the nozzles and losing quality of atomisation. The nozzles will see 50% duty pulses of 200psi water rather than say constant 100psi at lower flow rates. I'd be interested to see the quality of the atomisation on the AEM V3 nozzle with them driving the pump at 30% or 50% duty. Also I needed a solenoid anyway as the nozzles are in areas of the system that see vacuum. As I have the capability to drive a PWM solenoid with little effort and cost over a slower valve I may as well take advantage of that.
Atomisation is absolutely key because I intend on running pure to heavily water biased mixture to start with. One of the real issues with water is it is actually quite difficult to get it to phase change in the time available in an intake tract / combustion chamber. Getting the finest possible atomisation will increase the ease the water will phase change.
Originally Posted by oreo
Also, with the supercharger you have, if you inject more water/meth than required, it just means you are going to have to refill the tank more often. I don't think it will change your resulting HP/TQ.
Maybe others have input on this.
Agree with this certainly. I'm not expecting WI to be a +50hp bolt on and I am expecting to have to play around with water / fuel % and probably pre sc nozzle size to bias water % between the port nozzles and pre sc. What I hope to do is get to a point where the pre SC nozzle clips the extremes of the air temperature from the supercharger giving the charge cooler a bit less work to do but equally not flooding it and causing drivability issues from large droplets of condensate post cooler, as well as just draining the tank prematurely. The pre sc nozzle isn't really very big, its only 140ccmin (7.5% fuel with WI at 100% duty) There should be marginal gains from effectively increasing the adiabatic efficiency of the supercharger (less crank power required to drive the sc for the same mass air flow). Also the water will keep the rotors and bearings cooler which will be good for longevity and reliability. By installing the post sc temp sensor I am hoping to be able to tune and see the effect of the water % and inject enough to maximise overall cooling without going too far and exceeding quantity of water that can phase change inside the sc for a given flow rate / temperature.
If I'm being honest life would have been a lot simpler if I had left it at just the pre sc nozzle, I would have just monitored line pressure after the valve to make sure something was happening and monitored AITs or the post SC temp sensor as a failsafe, but I do like making life difficult for myself.
The point of the port nozzles is not for AITs, but to ensure the even distribution of water into the cylinders that will allow me to confidently remove fuel and add timing to try to reach MBT. Currently I run a very safe rich mixture, data logs show high 10s to around 11.4 AFR by redline, however I have noticed there is an offset between what my AFR gauge reads and what the ECU sees (that I am going to correct and have been collecting logs to do this before taking the car off the road to do the latest batch of installs). Reality is I am actually around 10.5 to 11.1 AFR by redline under WOT. It does seem to allow me to run decent spark advance even at high IATs in comparison to what a well matched turbo A/A intercooler system would see, but that excess fuel will be strangling the second, more energy rich combustion process in chamber and producing excess carbon monoxide. Using the water as detonation protection while I reduce fuel to a rich best power mixture (12.5 AFR apparently) should yield a more efficient combustion process. I will then see if I can increase spark advance to try to find MBT - again increasing efficiency. Being able to run the engine at best power mixture and MBT timing should help engine temperatures (I had an oil temp issue on my last trackday) as the main combustion event happens slightly earlier with less of the combustion chamber surface area exposed to the event, reducing heat transfer, and also lowering EGTs, giving my exhaust valves a bit of an easier time. This process requires best atomisation of the water delivered to the cylinder, which is what I hope the nozzle setup / PWM valve will achieve. So I hope to win a bit of power and engine temperature control with the port nozzles. I'm installing a 4channel EGT system on the car so I think with all the new sensors and adjustability afforded by the PWM valve we should be able to have a good crack at getting the system as a whole optimised (best hp / torque with stable AITs and engine temps under prolonged high load for reliability)
Hopefully that doesn't come off as defensive or argumentative, it's not meant to be, just explaining the theoretical reasoning behind the choices I have made. Hopefully there are enough sensors etc hooked up to the thing to be able to actually validate and verify those theories either way.
Well I meant to finish the exhaust off at the weekend but first weld in I ran out of stainless wire, so that's going to be this weekend now.
Just carried on with a few little jobs. I had located the WI PWM valve right in the way of the TPS sensor plug, so I moved the valve over a bit. I've decided to relocate the little fine filter to the outlet of the pump in the boot, rather than just before the valve. It will make it a lot easier to access and service than in the engine bay, where I would have to remove the supercharger to get at it.
My front wings had rusted through at the bottom and I have a replacement set waiting to go on, but I noticed the lower A post area of the actual car was showing some rust. Luckily it looks like it has been caused by rubbish being held against it by the front wing, i.e from the outside. I sanded it back and found all good solid metal. I treated it with Por15 pre treat, then over the top with the Por15 rust protect paint. I will give it another coat before I put the wings back on and I will use some standoff spacers for the bottom of the new wings to try to stop stuff collecting there. Hopefully crisis averted there as it was starting to take hold a bit.
I fitted the EGT sensors and if nothing else I think they look cool
They are the stainless steel closed end type, I didn't pay a huge amount for them and they had good reviews so I will give them a go. What I am trying to gain from these sensors is an understanding of how evenly the system is delivering air to each cylinder. The charge cooler is designed to distribute the air along its length and the supercharger outlet is relatively central, but obviously the design of the manifold did not have any flow analysis and was primary designed around very tight constraints to actually fit everything in the space required. I run batch injection at the moment but if it looks like the individual cylinder fueling is a bit out its not too big of a job to convert to sequential, just a bit of soldering really. I also think they will be a bit of a helping hand while tuning the WI, again mainly to check the cylinder to cylinder balance is still good and potentially as part of a failsafe to protect against a blockage on one of the port nozzles, we shall see.
I also spotted the loom side of the plug for my crank sensor seems to have broken a bit and allow itself to be depinned, so I have ordered a replacement for that.
Still got a few jobs to do before we are back on the road but the list is certainly a lot shorter than it was!
Wicked cool project.
I approve of the individual cylinder EGT. Trimming the fuel per cylinder could be a big deal on a setup like this considering the inlet manifold air distribution is uncertain. Dont take that as a slight against your design and fab skills though! It looks great IMO.
Wicked cool project.
I approve of the individual cylinder EGT. Trimming the fuel per cylinder could be a big deal on a setup like this considering the inlet manifold air distribution is uncertain. Dont take that as a slight against your design and fab skills though! It looks great IMO.
Not at all and thanks. The CFD analysis of the manifold consisted of me squinting at it and going 'that looks about right'
Seems to run alright and idles at sensible AFRs, but that is about the limit of the per cylinder info at the moment. I'd like a bit more info than that as I start to push the tuning.
Its one of the big reasons I didn't just stick with the single pre sc WI nozzle - I thought cylinder 4 would run a bit dryer and melt.
You should expect 30+ Hp gain if you manage the water percentage to fuel and the associated timing increase WI will afford you correctly.
I swear, once you go with WI, there's no going back.
One advice, if I may, will be investing in a cheap ultrasonic cleaner.
Nozzles on your manifold WILL have to come out about twice a year for a 5 minute water & white vinegar bath in the ultrasonic cleaner.
Amazing amounts of crud comes billowing out of the nozzles.
You should expect 30+ Hp gain if you manage the water percentage to fuel and the associated timing increase WI will afford you correctly.
I swear, once you go with WI, there's no going back.
One advice, if I may, will be investing in a cheap ultrasonic cleaner.
Nozzles on your manifold WILL have to come out about twice a year for a 5 minute water & white vinegar bath in the ultrasonic cleaner.
Amazing amounts of crud comes billowing out of the nozzles.
Ive heard adding a splash of isopropyl alcohol to the water helps a lot with algae forming. Not adding a ton though, like those people that insist you have to mix a much of methanol in there.
Ive heard adding a splash of isopropyl alcohol to the water helps a lot with algae forming. Not adding a ton though, like those people that insist you have to mix a much of methanol in there.
You are right.
The thing with alcohol dates back to WW2 piston engine bomber planes. Since those planes had to wait out in the open for weeks on end in winter conditions, they did not want the water in the WI tanks to freeze, so they started adding about 20% alcohol as an antifreeze agent.
WI companies keep pushing alcohol with aliases such as boost juice to keep you as a lifelong customer. Otherwise, you buy the WI system once, and they never see you again.
Water is the best calorie thief there is. And, it does a wonderful job of keeping the flame front in check, lowering combustion temps, and increasing dynamic compression through instant expansion.
You can safely run 100% water like I do. There is really no need for alcohol for performance purposes.
Algae and freezing are another matter.
You should expect 30+ Hp gain if you manage the water percentage to fuel and the associated timing increase WI will afford you correctly.
I swear, once you go with WI, there's no going back.
One advice, if I may, will be investing in a cheap ultrasonic cleaner.
Nozzles on your manifold WILL have to come out about twice a year for a 5 minute water & white vinegar bath in the ultrasonic cleaner.
Amazing amounts of crud comes billowing out of the nozzles.
I will be over the moon if I achieve that - but I am keeping my feet on the ground in terms of expectation. I made that mistake with the pulleys, I was sure it was going to just smash 40whp into it and I got 2whp for my troubles. I took another look at my timing map yesterday and although I think my high rpm advance figures are reasonable, it strikes me that my mid range is likely a little safe / retarded, so the majority of gain with WI could well be in the midrange and peak torque, rather than the headline peak power. We'll see, just going to take it one step at a time, don't do anything silly and DONT BLOW IT UP
Thanks for the tip on the ultrasonic cleaner I will have a google, I think I may invest in a water purifier also.
The thing with alcohol dates back to WW2 piston engine bomber planes. Since those planes had to wait out in the open for weeks on end in winter conditions, they did not want the water in the WI tanks to freeze, so they started adding about 20% alcohol as an antifreeze agent.
WI companies keep pushing alcohol with aliases such as boost juice to keep you as a lifelong customer. Otherwise, you buy the WI system once, and they never see you again.
Water is the best calorie thief there is. And, it does a wonderful job of keeping the flame front in check, lowering combustion temps, and increasing dynamic compression through instant expansion.
You can safely run 100% water like I do. There is really no need for alcohol for performance purposes.
Algae and freezing are another matter.
I've read / reading a couple of good books recently that you might both be interested in.
One is 'The Secret Horsepower Race' by Calum E Douglas - It covers the development of WWII airplane engines from the Schneider Trophy sea plane racers onwards, lots of reference to different fuel blends and of course water meth injection.
The other is 'Supercharging! A guide to superchargers, water injection and a lot more' by Greg Gordon. One interesting thing (among many) in this book is how through his experience injecting water at a 20% ratio to fuel is the minimum you should be looking at, and up to 60% would be reasonable. Way above any recommendation on any WI vendors site.
The thing with alcohol dates back to WW2 piston engine bomber planes. Since those planes had to wait out in the open for weeks on end in winter conditions, they did not want the water in the WI tanks to freeze, so they started adding about 20% alcohol as an antifreeze agent.
WI companies keep pushing alcohol with aliases such as boost juice to keep you as a lifelong customer. Otherwise, you buy the WI system once, and they never see you again.
Water is the best calorie thief there is. And, it does a wonderful job of keeping the flame front in check, lowering combustion temps, and increasing dynamic compression through instant expansion.
You can safely run 100% water like I do. There is really no need for alcohol for performance purposes.
Algae and freezing are another matter.
Originally Posted by Tchaps
I've read / reading a couple of good books recently that you might both be interested in.
One is 'The Secret Horsepower Race' by Calum E Douglas - It covers the development of WWII airplane engines from the Schneider Trophy sea plane racers onwards, lots of reference to different fuel blends and of course water meth injection.
The other is 'Supercharging! A guide to superchargers, water injection and a lot more' by Greg Gordon. One interesting thing (among many) in this book is how through his experience injecting water at a 20% ratio to fuel is the minimum you should be looking at, and up to 60% would be reasonable. Way above any recommendation on any WI vendors site.
You can go right to the source and read the NACA white papers on this. They called it "Internal Cooling". Really interesting stuff.
Ive been an advocate of running straight water for a long time, but for some reason the idea of it being "meth injection" has really stuck recently. Ive had a few tuning customers over the years that have been genuinely surprised when I tell them I they should just water if they do it.
From what Ive read, the meth was there for the freezing, and to add additional fueling in boost, something carbs are not great at doing. I have programmable fuel injection and live in florida, so Im not going to add meth to the mix. Especially if I would have to pull fuel out of the tune to get a good AFR, risking it going leak if the water/meth system fails or clogs.
I will be over the moon if I achieve that - but I am keeping my feet on the ground in terms of expectation. I made that mistake with the pulleys, I was sure it was going to just smash 40whp into it and I got 2whp for my troubles. I took another look at my timing map yesterday and although I think my high rpm advance figures are reasonable, it strikes me that my mid range is likely a little safe / retarded, so the majority of gain with WI could well be in the midrange and peak torque, rather than the headline peak power. We'll see, just going to take it one step at a time, don't do anything silly and DONT BLOW IT UP
Thanks for the tip on the ultrasonic cleaner I will have a google, I think I may invest in a water purifier also.
From what Ive read, the meth was there for the freezing, and to add additional fueling in boost, something carbs are not great at doing. I have programmable fuel injection and live in florida, so Im not going to add meth to the mix. Especially if I would have to pull fuel out of the tune to get a good AFR, risking it going leak if the water/meth system fails or clogs.
You can use the table switching function and switch over to richer and much tame fuel and timing tables if you run out of water.
A simple float provides the ground signal necessary to switch tables instantly.
Make sure areas below 100 kpa are identical in both sets of maps, so off boost city driving is not affected by the change.
I have been using table switch with great success for almost 10 years now.
You can go right to the source and read the NACA white papers on this. They called it "Internal Cooling". Really interesting stuff.
Ive been an advocate of running straight water for a long time, but for some reason the idea of it being "meth injection" has really stuck recently. Ive had a few tuning customers over the years that have been genuinely surprised when I tell them I they should just water if they do it.
From what Ive read, the meth was there for the freezing, and to add additional fueling in boost, something carbs are not great at doing. I have programmable fuel injection and live in florida, so Im not going to add meth to the mix. Especially if I would have to pull fuel out of the tune to get a good AFR, risking it going leak if the water/meth system fails or clogs.
I think I stumbled on those papers when I first started researching WI last year, I found them a little heavy going at the time, but I will revisit now I have a bit more understanding under my belt. The 'Supercharged!' book is good because it references those papers, but breaks them down to a level ol' muggins can understand.
I want to run a water biased mix for simplicity, it should do everything I want it to and avoids the complication of getting hold of and mixing Methanol.
The system will have the flow sensor and the tank level sensor to protect the engine, and use the flow sensor to switch to a more aggressive map when the water is flowing.
I would think that the water map would end up being someway outside of the knock free zone with just petrol so I do need to protect myself.
Thanks very much. What octane rating is your petrol?
When I first looked at your map i didn't see too much difference to my non WI map, but as I looked closer actually in the midrange you are running a considerable amount more advance than me, not so much in the top end. Is there much of a difference between your non WI and WI map?
TW the way I know the top two rows are the same - I swapped from the old hybrid spark table setup to a speed density setup. My MS2 only has 3x tables, and to run switchable hybrid I would need 4x tables. I took the top rows from my small crank pulley dyno session at 10psi, then my big crank pulley session at 14psi. I know those numbers were safe for both of those boost levels so I haven't moved from them. This will be the safe map so no point pushing it here.
Few jobs done this weekend. I finished the welding on the mid pipe section of the exhaust and added the mounts. I then realised that I will need to turn the car around in the garage to be able to tack weld the rear silencer on, and I need the car to be able to drive to do that, so I reinstalled the supercharger system. I added the temp sensors to the charge cooler radiator and piped most of the engine bay WI also.
So anyway a little apprehensive about firing the engine up again after a couple of months work, particularly without the rear exhaust silencer mounted. Battery still had good life in it surprisingly so I cranked it over until I got oil pressure then bombs away and it sprang to life . I was expecting it to sound horrendous with only the mid silencer attached but actually it sounds fantastic! Its not harsh like when I once fired it up with only the manifold attached for a laugh years ago. It sounds really deep and meaty. It is loud no question, louder than I would want, but not ridiculous. I'm actually quite surprised! I'm feeling pretty confident that with the second larger rear silencer it will bring that volume down right where I want it. Only issue was I seem to have a vacuum leak between cyl 2 and 3 that was making a loud whistling noise that needs a bit of investigation once I get the exhaust finished off.
Going golden already :-) Just about fits in there!
Waiting for some nozzle adapters for the sc inlet nozzle and the flow sensor for the WI system, then I need to wire it all up, mount the tank and pump, paint the new wings and mount the front bodywork back on then we should be good for the MOT test (yearly roadworthiness check in the UK). Then we can get stuck into tuning. Got a month before I have a track day so that feels doable even if I am running a really safe WI map.
Update: I welded on the rear box and it sounds excellent. Even when I fired it up in my garage the volume level was fine. Can't wait to see how it sounds when on the beans.
Very happy with this, if it was too loud I would have had a problem. I thought originally I would be able to get a resonator ahead of the mid silencer if required but as the exhaust took shape this space was taken up with the vband and flexi joint. I guess there is room between the mid and rear box but at that point basically the entire exhaust would be silencer.
Thanks Oreo, you definitely steered me onto this amount of silencing. I would not have shoved 4ft of silencer under the car if you hadn't posted what you had tried.
I'll get a sound clip when I finish off all the mounts and stop the stupid whistling vacuum leak up the front.
Just need to see if it has made any performance benefit now.
Wow, glad to hear things have worked out.
You are doing some top notch work here, and I am very interested in hearing how this works performance wise!
Thanks mate, me too. I think it is a bit louder than it used to be from outside, but it is definitely more intense in the cabin. I think it is a combo of the stiffer engine mount and less rubber in the rear silencer box mounting than the previous exhaust. Its not unpleasant, just more aggressive. I think also its been so long since I've driven it that I will need to to re-acclimatise to it, its definitely not a numb family run about.
02-19-2021, 01:48 PM
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