94AWDcoupe

iTrader: (125)

This may be an alarming post to some. Others are just gonna say I dont know what I am doing. I have been playing with turbocharged cars all my life. I built my first turbocharged bug when I was 20 and I have not been without a turbocharged car since then. I am 45 years old. I have been playing with the 4g63 exuberately for the last 10 years. I am well known around the tampabay area because my cars always stand out in a fast car crowd. I know how to build a car. The first bug I built used a crude water injection instead of an intercooler. It allowed 7 more psi than gas alone. That sytem used just a hobbs switch controlling a windshield washer pump. The world of water injection has come along way since then. Currently I have been using alkycontrol.com progressive sytem. He is local to me and he really has a good handle and alky injection. AMS designed a kit using his components. It works very well for what it is. My yellow car with 2.4/AEM/35R ran a 15gal and 7gal jet. My blue car ran a single 10g jet with a 2.3/20g setup.

The engine in the yellow car always ran with 93/alky. It lived a very hard life. The car was pretty much nothing but a go fast test bed/weekend racer. Plus about 40 passes over three years to update its progress. 1st pass ran 11.49. Three years later it ran 10.25. After 15,000 miles the cylinder bores looked like chrome. I wish I had a picture of those bores , but I left the block sitting outside and they rusted up overnight. The pictures to follow are of the blue car setup. It as well was run from day one with 93/alky. After 5000 miles there is considerable bore wear. A/F ratios were nothing short of normal. around 14.7 cruise and 11.0 wide open. Here is a pic of one of the bores. I couldn't get the car rolled into the sun like the other block but its clear enough to notice a few things. The honing marks are very much starting to disappear. The other important thing is the color. There is no brownish color to it. And the piston top is very clean.

Now take a look at what a cylinder wall that is going to last a long time looks like. This engine has 40k on it and the honing marks are very visable. And take a look at the nice brownish color. That brownish color is oil that cooks into the surface of the metal . This is a good thing. That means there is oil on the walls as the psiton goes up and down. The last pic is the piston top that was in that engine.



I dont have all the answers to exactly why or when the cylinder wash is happening. I currently believe most of the damage may be occuring during coast down when the A/F is normally very lean. With a surflow pump at 200psi there is a good bit of raw alky that flows into the pipes after every incidence of boost. It is very clear by A/F ratio gauge that the mix goes dead rich on coastdown when it should be at 25/1 or higher. I am not completely sold that is the only time cylinder wash is happening. What I do know is that the insides of the combustion chamber are very clean. And whatever is cleaning it it cleaning the needed oil film as well.

dubbleugly01

iTrader: (24)

what does alkycontrol say about all this? I'm using their setup (the AMS kit actually), and they should have some good experience with the longer term effects of running alcohol.

Thanks for posting the pics, they tell a thousand words.

EvoDan2004

iTrader: (94)

so what your saying is running alky or 100% meth is bad and begins to wash the motor out??

cpoevo

iTrader: (1)

Here we go again.

Vigo

What about just using water? Does that have any bad side effects?

DRFTKNGG

iTrader: (8)

Oil changes and how long it went without one and how many times should play a role in there....

dudical26

iTrader: (17)

94AWDcoupe - based on your finding are you going to continue to use meth?

I am looking to get meth and I obviously don't want to damage my motor. I honestly don't think I will put more than 50,000 miles on my car before I sell it. Do you think that washing out the bores would make my motor go before then?

Ultimate CC

iTrader: (122)

Im not so sure its the left off throttle because as soon as you let off the throttle the TB closes and extra meth gets trapped...

edit: I see where you are coming from now...

dudical26

iTrader: (17)

I think he means that even with the throttle closed the accumulation of meth dropplets on the walls on the intake manifold will still have access to be burned by the motor even with the throttle plate closed. Also even with the plate close, there is still some air that goes into the motor to keep it idling.

SlowCar

iTrader: (4)

on most progressive pump speed systems, AFR is only perfect in the gear the car is tuned in, in the rest of the 4 on a 5speed and 5 in a 6speed, AFR will be all wacky. 14.7:1 is stoichiometric combustion, ~12.5 is idea......low 11s, 10s...rich - excess fuel, a contributing factor to the above?

https://www.evolutionm.net/forums/sh...d.php?t=185062

Another contributing factor is also what was brought up by 94AWDcoupe - injecting the wrong amount at the wrong time...

https://www.evolutionm.net/forums/sh...7&postcount=12

dubbleugly01

iTrader: (24)

I just checked my piston crowns through the spark plug holes. After 2 months using 100% meth through a size 15 nozzle, my piston crowns still have a carbon buildup on them, for whatever that's worth. I've been through 5 gallons of meth in that time period.

94AWDcoupe

iTrader: (125)

I am not giving up on injection yet. I am switching to injector like control of some sort. I am hoping the issue is pump pressure overrun. The other possibility is intake wall wetting. If this is a factor even the injector control wont solve the problem. Then four injectors very near the originals will be needed. The new aquamist setup looks to be a very nice setup. But I like to keep my systems as simple as possibble. The aquamist is not what I would call simple. FJO also has a good simple setup but pricey. I really like the way aquamist is using injector signal to control injection rate. This will make tuning a breeze. Very flat A/F should be easy to achieve. You only have to get the injection rate in the right ballpark, then you just tune a/f like normal. Since changing the injector duty of fuel injectors will change both at once.

Oil was changed 600-700 miles on yellow car, and 1000-1200 miles on the blue car. It may be that I am injecting more than needed , Reducing size of nozzles should reduce the size of the problem. But when injecting 100% meth there should be no limit to how much could be injected.

Whats really agravating is alky injection using meth creates all kinds of system challenges. The stuff is just too corrosive. I am thinking it may be best to just inject ethanol (e85 or e98) instead. Then you could use a regualar fuel pump and standard injectors. Much more reliable and way more precise.

C6C6CH3vo

iTrader: (9)

Did that engine show any compression degregation?

If the alcohol made it's way that far you would think the rod bearings would show signs of damage.

What cyl # showed the worst signs

twostep

Is the picture showing us the blue car's cylinder a built engine?
Also the pics below are signifying a stock bottom end?
There is a reason why I ask.

Ultimate CC

iTrader: (122)

All I know with my evo with the snow kit that I have over 15k and 65 gallons through it and the compression is dead on across the boards...I will take some pics of everything whenever I decided to pull the motor and build it...