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Intercooler removal, water injection only

7K views 12 replies 1 participant last post by  Coolmist 
#1 ·
Hi

I totally removed the intercooler and now rely on methanol/water injection for cooling



Bankai






After a blast on a 22c day the log temps are hitting 90c, OK it was a hot day but jeez..



MR2 Log, no intercooler, post compressor WI - YouTube






This is with an Aquamist 1c system (basic boost triggered pump) with a 0.7 and 0.5 injector post compressor






I thought I would try adding moar warta.

After looking around at the available kits I found the Devils-Own kits to be the best for price and atomisation.

Twin tanks in the boot, separate one for each kit



The Devils injector will be placed looking into the "eye" of the turbo as close to the impeller as possible, doing this is not easy....the best position on offer is firing the injector from the wall of the hose so I adapted some mesh to give me the optimum position, lets hope it stays in place and does not offer too much restriction :shock:








the injector is just spraying pure water at the moment and hopefully will help lower temps a bit closer to 30c, this injector should flow circa 400cc per min






From reading up this position changes quite a few things...the compressor map can be shifted allowing more power at higher RPM, the turbo becomes more isothermic, the speed of sound in the gas and the mach number of the compressor blade tips should also change....interesting stuff eh?




Air filter in position








After a test drive in cooler ambient conditions than the last logged run the inlet temp has dropped by circa 40c



MR2 Log, no intercooler, pre+post compressor WI - YouTube




Ambient temp was 16c, injection trigger point for the Aquamist system was dropped to 4psi, Devils system was triggered at 2psi and ramps up to max flow at 19psi (boost sensitive progressive system)

Boost temps were seen to be around 40c, I never saw 50c on the test

I will try for a slightly larger injector soon for lower temps, remove the Aquamist system (as it's atomisation leaves a lot to be desired) and go twin injector on the devil kit for pre and post turbo injection.
 
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#2 ·
Ok so the next stage I took was the removal of the Aquamist system and I added twin injectors to the Devils system, 600cc pre turbo, 400cc post turbo (D04/D05)

I relocated the pre turbo injector to the end of the air filter, this we know is not ideal, I hope to change this soon.

Water injection supply lines were rerouted away from heat source.

Post turbo injector 400cc (D04)


Devils progressive controller pic to be added.

Pre turbo injection position to be added.#






Datalog..
Run3_daytime - monosodiumphosphate's library


Ambient temps were back up to 22c and this is the first daytime datalog after my one last night was lost due to incompetence lol

I used a 38/62 ethanol/water mixture and I was surprised that if anything temperatures were higher than the previous run...yes ambient temps were 4c higher than the previous test but I saw almost 70c at one point at the very top of the RPM range at circa 130mph?...in general temps were around the 50c mark on boost.

I thought a total of 250cc extra liquid was injected on this run but I had incorrect advice as to the flow rates of the injectors

I planned to inject a mixture of 78% alcohol* rather than the 38% we had in the last run to test this theory.



The temp did not drop and after a close look at the injector flow rates

and it seems I am simply not injecting much more liquid than my previous tests...only 750cc per min total, another injector is planned for the next test to bring injected amount closer to 1150cc per min




*due to a lack of ethanol I am using a small amount of isopropanol in the ethanol/water mix to bump up the alcohol content.
 
#3 ·
The D04/D05 injectors are moved back to the injection points I was using with the Aquamist system...I adapted the injectors for straight fitment at this time.










Rear view of injection point/s









Fitted.

















D05 pre injector moved back to the turbo entry point..I set it back about 1/2 inch from the turbo








Dump valve added










The engine bogged and misfired on this run with well over 1000cc per min being injected, temps were closer to 40c on this run and hit a max of 46c on an extended high speed run at near 130mph, I would have liked to have added a full datalog for this run but I am having trouble using the screen recording software.

I played with different mixture settigns but the misfire would not clear...it seems that either the mixture was simply too rich (dipping under 10.0/1) or had too much water content to ignite.

With the coilpack dwell time being too high as it is I will need to get the car remapped to take the extra fuel into account...for the moment I will drop a jet size for around 900c per min and take some more measurements.

I may also use more smaller jets amounting to the same injected amount to offer a more atomised mixture to the inlet to help drop temps even more...I dont know how much of a drop this can provide but right now anything is worth a shot!
 
#4 ·
I fitted two more injection sites in the turbo scroll and fitted much smaller D075 injectors in those sites...the idea was to give a more even distribution of cooling mix within the turbo and reduce the chances of dropout on the walls of the turbo whilst also taking advantage of the very slightly better atomisation that a smaller injector provides.







The pre turbo injector has now been reduced to a D04 (and I plan on reducing this to a D02 when I can)


I took the car for a test run last night and although the WI system was providing something like 25% less coolant/mixture and ambient temps were around 21c the inlet never went over 50c even on an extended high speed run....something is working a LOT better here!

The mixture was set at around 50/50 and another factor I should mention is that the dump valve was also leaking a bit...I am sure this only would have made the turbo work harder and acutually increased inlet temps so now that has been repaired I may get some datalog tonight.
 
#5 ·
Well moar methanol arrived today so I filled up a 15/75 water meth mix and went for a datalog run...I managed to change the software so the inlet temps are much easier to see too!

After the last run on a 50/50 mix I was expecting temps to be quite low but this was not the case!!!, the temps smashed into the 80c region pretty dam quick



I am not sure why that is...its pretty much the worst temps I have seen yet and I had to check the tank volume to assure myself that the WI system had activated at all on this run

AFR was hitting 10.0/1 which is the lowest my AEM will read (so who knows what the real AFR was)

If this is going to work we are going to need a LOT more liquid injected at this mixture level


Another two runs on different mixtures show the same thing...massive spike on first application

Run 2 50/50 methanol/H20



Run 3 50/50 ethanol/H20



It was obvious something wasnt right here...thats not what you expect from a WI system, a leak was suspected but upon checking could not be found :(
 
#6 ·
So it seemed that rather than a leak it was air that was pushing through the post turbo injectors and managing to empty the lines through the pre compressor injector. This gave a delay in injection delivery so temps were seen spiking upon first application in the logs above.

This was rectified by fitting a check valve just before the pre compressor injector.



A D05 injector was also fitted between turbo and dump valve at this point.

*Injector pic to be added*

The next run went very well..helped along by low ambient temps (16c) and a nice dry road allowing me to hit max RPM and hold the throttle wide open for some time, temps were back in the low 40's at max RPM and stayed in the 30c region at lower RPM's which is almost exactly what I aimed to get at the beginning of this project :)

The initial spike in inlet temps we saw in the last log was absent from the data, the check valve doing its job!

The car didn't bog or misfire, nice clean power although fueling is (as expected) still pig rich and requires some remapping to clear up.

I thought I had saved the format from the last log I done but for some reason it reverted back to normal so I have done several screenshots.


Initial application of throttle from 2k through to approx 6750rpm (engine limiter), 42c max inlet temp recorded




Into third, max inlet temp 43c at 6750rpm




6750rpm in 4th gear shows 44c


The other two high RPM peaks further over to the right again max out at 41/42c


I may add a touch more WM mix for the next log and I also have managed to source one of these...after a bit of grinding it should be acceptable and is better than what we have to house the pre compressor injector at the moment!

 
#7 ·
Another D05/5gph injector added..hope to shave a few more degrees off the inlet temps on the next midnight run



I would guess that the temp just before the cylinder is a good 5 degrees lower than the temp i have recorded pre throttle body...IIRC atomisation suffers at under 30/40c so I have pretty much suceeded in what I aimed to do at this point and the extra 5gph injector is not needed really.
 
#8 ·
Interestingly the extra injector didn't make a lot of difference...I expected in the region of 5-10c drop now we are injecting around 1350cc per min but it was more like 0c-1c. The system is not leaking and I am still wondering why we did not see a more significant decrease , could it be that no more methanol can evaporate into the airstream and I either need to increase water content or add another chemical into the mix?

The ambient temp was also 4c higher than the previous run so this might actually explain the lack of expected drop in temp, another midnight test on te same injectors should confirm this theory.

I believe that 250cc is about the maximum amount of water I can inject into a 2.0 engine at this boost pressure..whenever I have tried to inject beyond that figure on this engine it has bogged or misfired so with a 10-15% water content in the tank on this run it would seem I am almost at that limit already

On a much longer run than normal on a 20c daytime blast we saw temps in the low 40's at high rpm and at one point just as I came off of the throttle a split second before I changed gear temps hit over 70c which again is not something I expected!


 
#9 · (Edited)
The ambient temp was 4c warmer than the last test and I did see a 1c drop in temps on the day so maybe that accounts for the few extra degrees I was looking for, I have also been told that I should not be anywhere near maximum saturation point with the amount of meth I am injecting so the ambient temp theory seems to be the only good reason.

This is a pretty cool graph that shows just how important water injection is on a turbo car!, this graph shows knock levels on the same car, same tune, just water added on boost!!




It goes some way to show why it is that my engine is in one piece where other MR2 engines have simply gone pop..., its all about cylinder pressure and detonation.

The water cools the walls of the cylinder preventing the cracking some engines suffer, it cools the piston, it cools the inlet, lowers EGT, reduces cylinder pressure, increases the octane of the fuel, reduces knock.

When used pre turbo it also spools the turbo earlier as it changes the density of the charge, changes the mach speed of the compressor, allows the turbo to flow more/hold on to its power for longer and pushes the turbo towards an isothermic state.

If you also add methanol into the mix it just makes the turbo go mad!





Turbo cars need WI!
 
#10 ·
#11 ·
Another change to the pre compressor injection point and I have a feeling it may not be the last, the nozzle has been brought forward just over 1.5 inches..it is now within 5mm of the compressor nut, maybe this is too close for comfort?













Another change to the pre compressor injection point after noticing the wear on the compressor in the previous post and I have a feeling it may not be the last, the nozzle has been brought forward just over 1.5 inches..it is now within 5mm of the compressor nut, maybe this is too close for comfort?











It's not easy to strike a good medium with the injector placement...I think the previous nozzle position may have allowed the WM mix to hit the sides of the turbo inlet and pool into larger droplets which have damaged the blades as they have impacted, I dont know what is the best distance from the compressor but after rigging a very basic test I believe it to be 8-12mm away from the compressor thread/nut
 
#12 ·
Progress has been slow recently due to the failed Devils own controller, I have been waiting for a new coolingmist replacement.

The only other change that has been made to the car is to the IAT sensor position, it has been moved into the stock location.

Ambient temp for this midnight run was 20c, it looks like the lines filled on first application of WOT before temps became stable at circa 50c.





The new controller allows me to start injection at 1psi rather than 2psi, on small throttle openings with around 3psi of boost temps drop into freezing!, the logs did not show this before so maybe these recorded inlet temps are due to the repositioning of the IAT sensor..maybe the meth is pooling at this point




In short the inlet temps at WOT were higher than I expected and temps at low throttle openings were way lower than previously recorded.

I plan to move the IAT sensor back to it's previous position and replace one of the 5GPH nozzles for a 10GPH or maybe I could add another pump into the system to boost pressure to the nozzles
 
#13 ·
Please note these last posts were originally written in summer 2012.






IAT sensor was moved back to the previous boost pipe position and another log recorded, the ambient temp was around 26c+ tonight...very hot



Temps remained in the high 40c range which is to be expected given ambient conditions.

I think I may swap out one of the 5gph nozzles for a 12gph nozzle when the car gets mapped.



And that ends the testing for this year, with the temps in the 40c region with hot ambient temps there is not much that needs attention before the car is mapped at the beginning of the next season, as mentioned we will increase the injected amount to take the extra boost that will be used into account.

I am sure that anyone that has read this far will want to see a dyno graph of the finished article and hopefully the wait will not be too long.
 
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