Cavitation and other fun, part 2

After a day of waiting in Penrith for our golf to have it's seatbelt fixed, I came home to fix the beetle. Emil helpfully picked me up from the station and we came home and pitched into it. He's a master wiring man and we knocked it over in not long at all.

One of the main pipes coming from the filler neck runs about a metre of tube into the inlet of the pump. We filled the filler neck up with coolant with antifreeze. As soon as Emil turned the ignition on, the system started bleeding itself. In the end, we put somewhere in the vicinity of a litre of coolant into it.

I guess the next trick is to see what difference it makes to intake air temperatures now the fluid is actually flowing round the system.

Cavitation and other fun things

I've spent the last week or so trying to sort out a few things. Among them was a bunch of oil leaks. Some of it was me not tightening things enough, some of it was... werl, being an aircooled VW. At the same time I've been facing an ongoing issue with the intercooler system. It should be logging intake air temps (IAT) about 10deg higher than ambient. Instead, the other night when I went out driving on a 22degC evening, the IAT was 47degC. Head temps are fine, but the intercooler is not working as designed.

I came to the conclusion that the issue had something to do with airlocks or the pump. Today I ran the pump on it's own to see how much movement I had through the filler neck. The answer was, "none". I spent a while squeezing hoses and the like but still no luck. So then I started cracking coolant hoses at joints. A whole bunch of places had fluid but it wasn't moving. The outlet of the pump had foamy coolant coming out. This means there's air somewhere in the system and the pump is cavitating. Jacking up one side of the car helped it suck up some more coolant, but it still wasn't working.

On the advice of a friend, I tried this... getting the pump to pull water up out of the bucket.



No cigar. No cigar at all. Even when I put a garden hose into inlet hose it wouldn't pump water out at any pressure. So after a bunch of stuffing around, I pulled the pump out. The good news is, the pump actually works. It works well. I came to this conclusion... the pump is in the wrong place. First up, it's a centrifugal pump and doesn't self prime. Second, it was mounted with the inlet pointing down, halfway up the cooling system.



In short, it was always gonna be a fail. Sadface. So neat, but so useless.

So, what to do next? So I started climbing around the car and trying to figure out where to mount the pump and how to mount it so I could get coolant to it. Oh what fun. There wasn't anywhere in the engine bay I could find that the pump was going to fit. There's already so little space in there. Even if I could get it in there, getting the hoses connected to it and mounted is next to impossible. So I started looking under the car...

Oh man, so much junk under one car...

So after agonizing for a while I figured, "what about where I mounted the oil filter?". And amazingly it worked.



I'm beginning to understand how Porsche ended up with ridiculous tea tray spoilers and the like. I'd rather not put the pump in the rear guard except for a few things...

1. It's at the lowest point in system or close too.
2. It hangs directly off the bumper mount.
3. All the fluid should drain directly into it so it bleeds itself.
4. The oil filter is there on the other side and works ok.

Now all I have to do is run some hoses and re-route the wiring. Time to call Emil again.

So that explains it...

So I just took the top of this intercooler system filler...



And it was empty. Yes, this pic is before I attached all the hoses. This is the second time I've found it losing coolant. Hmm. Now I get to figure out why.

More driving, tuning, beer and shiny bits

In an effort to try and fault find via datalogs, I was back out in the car again today. I only drove to the next suburb and back, got a bit of fuel and the like. Of course, with any VW, it's always an adventure. The first thing of course was getting out the driveway. The exhaust hanger scraped again.

Then off to my mate's place data logging on the way. When it's cold, it's got nothing down low... and I mean nothing. Just off idle it fluffs around no end. In traffic, it's better. Third gear is really where it all happens though. By then though, you're above 35mph and breaking the law. 1st is over very fast and 2nd isn't much better. I dearly wish I'd got a close ratio 1st/2nd set installed. The clutch is also a might too clampy. It's a touch chattery. I'm getting used to this, but it is hard to get it off the line at low revs. Be interesting to see how my 12yo daughter copes with this in a motorkhana. Hmm...

It's a hot week for the first week of March, and the car is feeling it. Just in traffic driving across one suburb I got intake air temps up near 55degC. Ie, too hot. I adjusted the fan and intercooler pump controls down, but even still couldn't get the IAT down past 50degC. I think I might have to revise the way air is getting to the radiator. It probably works well at 100kmh, but not so well in traffic and round 60kmh. Strangely, oil temps in the sump are still only 50degC. Head temps were 115degC. So hotter than the freeway, but then the engine fan isn't moving as much air. This is the weird thing, the motor itself is running quite cool but the intake temps are not so much.


The other frustrating thing about driving the car (that I'd forgot) is the position of the gearstick and steering wheel in 4th gear. You can see it in this pic. My 6'4" knees are jammed in between the two. I had the same issue with test driving a subaru liberty some years back... only it was the handbrake in the liberty.


 
Having picked up a few things and dropped my wife's phone off to be resuscitated, I drove back to the local petrol station to get some fuel. The first one wasn't selling 98 octane so I left for a truck stop round the corner. Having filled the car and turned the laptop back on I was accosted by a friendly truck driver. "Darren", least that's what his shirt said, tried to stick his head through my window to talk to me.

Why do people do this?

The conversation went a bit like this...
Darren; "is that a 1956?"
Me; "yes"
Darren; "I have a transporter. Do you drink beer?"
Me; "does the pope wear a funny hat?"
Darren; [lots of talk about beer, most of which I'll pass over] "...you've got to get this beer, it goes with the car".
Me; [being polite] "ok"
Darren; "when you have you're first mouthful of it, you'll go [f-bomb]!!!"
Me; "right"
Darren; [tells me where to get it and waves me off]


This is the beer, I think... Now don't get me wrong, I like beer. I like German beer, well some of it. What I'm struggling to understand is how it goes with my 56' beetle beyond being German. But what the heck, I'll pick some up and try it. I'll take one for the team.

After that I headed off home with the laptop on autotune. I pulled up to the first corner and it started misfiring. Grr. I guess it's been running rich for so long the plugs have fouled. I got it running on all 4 again, but it's not great. Hopefully all my logs can help some experts help me to sort this all out.





When I got home, my latest purchase arrived. Direct from China and just $8.80.



Wheel nut caps. Plastic with chrome coating. I even got 2 removal tools. Some of you might be thinking 'what the heck is he doing?'. Well there's a few things going on.
Firstly; everything has been done to VWs wheel-wise. Ev-ry-thing. So, how to be different?
Secondly; I don't want expensive, wide, shiny, alloy wheels on the car.
Thirdly; I want to keep stock width wheels and skinny tyres. My only other option is steel 356 replica wheels. They look great, but I'd still want to paint them black and that means the price of alloys anyway.
Fourth; I love that 1950's hotrod thing. Simple, different, innovative and cheap. That's the thing about the original hotrodding. The cars weren't that wild looking often, they were very clever and well thought out. Cal-look VWs looked the same to begin with. No BRMs or EMPI 5 spokes.


So, I hit the garage. Here's the result. It's super subtle, but I reckon it works.

I still think I'm not done yet. I reckon there's more I can do with the wheels. That'll come in the future.

First freeway drive

I spent some time last week working hard to seal the engine bay on the right hand side. This was to try and get air going into the engine to be cooler. I had intake air temps up round 60degC. A bunch of guys on STF forced induction forums all told me, those temps need to be lower. There was the extra issue of not enough coolant in the intercooler circuit.

There was a lot of fluffing around trying to get it all to fit and seal as best as possible. The dipstick was a particular pain. In the end, I found this solution.

It's a minecraft whale! Ok, maybe not. In position we ended up with this.

 



As you can see the air intake ends up much higher up in the engine bay and right near the edge of the decklid. The gap left by the prop allows more cool air into the aircleaner.



So with all that done, I was ready to drive it. I was keen to go for a drive on the weekend but work kept me away and I no chance to get the car out until this morning. I drove the car around 25min minutes to go and see someone in hospital. It's been very hot over the last three weeks. Heat is the enemy of all aircooled engines, so I wasn't super keen to take it on the freeway. However, I figured, it's all sealed in and it's not stinking hot. So it was about 28degC or there abouts when I got onto the M2 motorway just near Blacktown. That section of the M2 freeway has a hill that's 10km long. It's not especially steep, but it's constant. Good for running an engine in and charting heat temps. It's also good for medium load auto tune. So off I went.

The news I have to say is good. Here's the gauge cluster I get in Tunerstudio.


 

Intake temps didn't get above 50degC (122F). For various programming reasons, the intercooler pump and fan didn't come on much at all. Better still, cylinder head temps didn't get above 100degC (212F). For a hot day pushing a car up a hill, that's pretty awesome. Oil temp in the sump didn't exceed 60degC (140F). At 100km/h, the motor wasn't working hard and it was doing 3200rpm.

In fact the only issues I really had were to do with the engine dying when I got off the throttle coming up to the lights. I thought I'd tuned this out of the engine, but it seems when it's hot, that's what happens. If you work your way down through the gears and give the engine a little throttle, it doesn't die. That gets a little annoying.

I was hoping to datalog the car on the way home, but the battery on my laptop died and I failed to charge it properly in the hospital. But not everything was lost. I drove home along the M4 freeway first at 100km/h then 110km/h. The car is loud inside, but it doesn't worry it. Oil temps again, stayed at 55degC until I got off the freeway. Even then, it only reached 70degC whilst sitting at the lights.

I know a few of you are thinking other things though. What about boost! To be honest, I've not driven the car on boost much. What I'm trying to do is to get it driving well in light and medium driving range. I'm pretty sure I'm not gone wide open throttle yet. Certainly, I've barely got near 4000rpm yet. Sure I've heard the blowoff valve, but the motor has LOT more to go yet. The rev limiter is currently set at 4500rpm. I can hear the turbo spinning, but I'm not there yet. I've given it a little bit of a hard time and it's capable, but I'm nowhere near the 7psi it's got with the stock wastegate spring.

That is still to come.

Also scraped the muffler today. The back of the car needs to go up and so does the dump pipe/muffler. Hmm, fun.