JT's Polo Building Adventure!

[sambb]

The other option is to just not inject post throttle body. Post throttle body will be more likely to get actual water droplets into the cylinders themselves which is good for knock prevention but can cause wall wetting in the plenum as the mixture doesnt have much time to evaporate. Pre throttle body will give the water meth more time to evaporate into the airstream thereby dropping the temps and should theoretically wall wet less. I inject between the MAP sensor and the throttle body. You can just get a bung welded onto the MAP pipe to achieve that. Added benefit of doing pre throttle is that you dont have to use a solenoid as the IC pipe never goes into vacuum so it cant siphon your system.

[JTop]

Update

So WMI AEM injector has a check valve, tried testing by blowing air through it and it wouldn't let anything through, so at high pressures it shouldn't be able to suck any more out of it than it has pumped through.

I sat again and tried thinking of a better way to mount the injector and I just don't have enough line to run it any other direction than from bottom facing up. I COULD also have done side facing the front but that situates it closer to the ambient inlet temperature sensor than down facing up.

Lined up the front end perfectly, had my younger brother to help out so it would be level and back in the correct place! Headlights back from my friend who done PPF on them, should keep them looking mint for a long time! All other small bits and bobs in the engine bay have been worked out and completed, there isn't much left to do there other than FLUIDS! Ordered everything I'm missing early last week, slight delay because one item was out of stock so full order was delayed. Not fussed for how much I'm paying for the whole lot.

Friend's Stage 3 Polo arrived at my driveway today and it was asking to fix its honeycomb center grill. Popped the bumper off and seeded it in without too much breaking force. Put it all back together and away he goes!


Started checking if I was able to put a map to run the car courtesy of Gavin! But... ran into a fun little issue of having a elcheapo VCDS cable Was a freebie so I didn't mind, but need to get myself a proper HEX+CAN cable for potentially a longer run. I have a little OBD11 dongle but it's eh. Worst waste of money for the Polo because there ain't much it can do for you automatically.

I also started working on putting in the coilovers. Got drivers side completely out but then I got tired and routed the WMI line to the boot, where I've got just. JUST enough to get it into the pump and have it situated in a nice position. That was a fun job!


Question. Tank can't sit 30 degrees offset, or can it? Might run out a tad quicker but gravity will still work, was planning on mounting it on the new rear strut bar when it arrives this following week. Then while it gets powdercoated, run a temp bracing setup for it before replacing.

Just last few things tomorrow, WMI wiring, coilovers, big brakes and finally to put the front bumper on and then to wait for all the last few small things to happen over the next few weeks.
Cheers

[sambb]

Think there’s a genuine vcds cable in the classifieds.
Yeah you want that tank upright. Otherwise you’ll be triggering the tank level sensor which will **** down your pump prematurely.

[sambb]

Didn’t swear promise. That said shut.

[sambb]

Yeah the check valve will crack at 1 bar probably, but in the direction of water flow. So say your pump is putting out 100psi well your check valve will consume 14.5psi if that just to stay open. The idea though is that once the pump is switched off the check valve will snap shut to prevent dribble or trail off from the jet as there is always some line pressure that remains between pump and jet.
I’m just concerned that 20 in hg will be enough plenum vacuum to drag that check valve open and draw water through the jet at idle. Did the aem kit come with the USRT post throttle body plate Ie intended to be run post throttle? If not maybe ask aem if their check valves jets can resist 20 in hg of vacuum without being drawn open.

[JTop]

Update

Sam, this setup was run previously by another fellow polo owner who was running stage 3 with everything I've currently got in the car. As for the suction, I'll do a bit of research on that AEM check valve to see if there is anything else with it.
I'll try run the tank as vertical as I can. Got a few more modifications to do that I haven't gotten to yet


Yesterday(Monday) got the following finally finished!
Big brakes are in and bled, going to need another bleeding probably after I cycle them a bit. That is all done finally
Front Coilovers, built and installed, got to set the car down and adjust them accordingly, but I think I've set them to an appropriate height

Engine bay has just the pod shielding conflicting with the ultraracing bar, so that'll get fixed up tomorrow

Got a cable from Gavin after I got the BBK and front coilovers done
Threw a map on again, courtesy of Gavin! Filed up all fluids (oil, coolant(made a 5L mixture 40% coolant, 60% distilled water), brake(bled front brakes and clutch again because I wanted it tougher!)) Only couldn't do trans because shop took semi synth instead of the full synth and I paid for the full synth... Yay going to go be a Karen and complain hehe
And finally let her run for the first time in a week and a half!!!
All was well except...


Stupid me forgot to tighten one of the oil return bolts
Hour later, got that done but can't turn the car back on because it's 11pm and my neighbours bedroom is located on the other side of the garage's brick wall

Tomorrow the front bumper goes on and it gets a trip around the block!
Don't worry Gavin! N75 is unplugged ahahahaha. I don't want to blow the build up this far into it


Cheers

[JTop]

Car's on the road! Did one slow lap and I'd prefer to bleed brakes once more all around before I'll be satisfied with it.

Started on the other Polo, rocker/cam cover leak has gotten bad so have already dismantled it, getting it all done and dusted by tomorrow afternoon. Will update on the whole process.

Sam, so I think I might move the nozzle back to be in front of my map sensor, just before the throttle body. As mentioned by AEM:
Nozzle must be mounted such that it is higher than the tank(don't think it will be once I mount the tank, will try to lower it more, but would need to adjust the nozzle direction). Failure to do so may lead to fluid leaking into the intake tract due to gravity or siphoning(you were right!), which may result in engine damage(not good). Nozzle MUST be mounted before the throttle plate. Nozzle should also be mounted after the MAF sensor, if present. Nozzle must also be mounted after any intercoolers. In most instances, mounting the nozzle 6–8” ahead of the throttle body provides an excellent combination of air charge cooling and combustion control.

So will think of a suitable method of threading it into the aluminium that I won't have a vacuum leak/loss of pressure.
I think this spacer would be a suitable option if running a plenum manifold. ? Yes/No

Cheers

[sambb]

good stuff. AEM are from the US so the jet is most likely a 1/8th-27 NPT or some sort of pipe thread. All you'll need is a female aluminium weld on bung like this:

1/8 NPT QTY:5 ALUMINUM FEMALE WELD ON / WELD IN FLANGE FITTING BUNG,LOW PROFILE | eBay

So yeah given that you don't have a solenoid I'd run the jet pre throttle body. The spacer is fine to run provided you have a triggered solenoid that cuts off any water supply to the jet below a certain boost threshold including at idle when vacuum could draw on it. Without that I wouldn't run it.
What size jet do you have. Without the car being specifically tuned for water meth, you don't want to over inject or you'll go backwards. Hopefully your system will run off a fuel injector signal so that the amount of water injected is proportional to fuel delivery. Then if you get your quantities right you'll get a good cooling of the airstream and the lower temps as seen by the inlet air temp sensor will have the ecu trying to maximise the ignition advance and then continue to do so as the knock sensors will not be triggering resulting in timing pull. Too much water though will make it sluggish coming onto boost and you may even get misfires. I found that bringing down the plug gaps from 28 to 25-26 thou made the engine handle the water meth better.
In my car with water meth on, it'll still pull the same <3 degrees of ignition timing in bits and pieces here and there across the cylinders. It's just that it'll be doing this whilst running more advance than if the water meth wasn't on.

[sambb]

YouTube

a friend of my mechanic buddy put a 0.6mm aquamist jet in pre throttle body on a YB cosworth build. It was a centre feed plenum. They put a Perspex window on the end of the plenum to get a good view of what was happening in there. It's a washing machine isn't it! Maybe not too much water in total but perhaps too much in the one location making for non gasified water meth in the plenum and/or wall wetting in the plenum happening too. But you can see that injecting more than needed isn't going to help.

[Sydneykid]

I really don't understand why you guys persist with petrol and band aids like water injection when E85 is such a superior solution without the complications and risks. I've been running E85 for over 10 years and for any performance engine it's a no brainer, especially with forced induction. As you are changing fuel pumps, fuel pressure and injectors together with a custom tune there is simply no reason not to take advantage of the alcohol benefits.. Reduced combustion temperatures, almost total absence of pre ignition together with reduced oil and water temperatures are some of benefits. Maybe if it's a daily driver and you live a along way from an E85 source there may be a case for not taking the step, but for a weekend use, track day, performance vehicle it's so worthwhile.

Cheers
Gary