Shoptalkforums.com

This is kinda counter-intuitive for a lot of us I guess. However, when you started talking about lots of throttle and cool heads, I totally got it. The motor is an air pump. If only a small amount of the air passing through is burning with just a little fuel, the rest is cooling it.

I'll have time on friday to mess properly with advance. I'll also have an extra set of busy fingers who likes to mess with electronics. For now, getting the motor in vaguely the right spot mixture wise will work.

BTW, you looked at my table and said I didn't have enough advance. How much more would you add as a starting point? Remembering the motor is a stock TP1600 (comp ratio, pistons, valves, heads, end castings) for all purposes.

A t1 chamber burns a bit slower/needs more timing, so I can only guess.
Below 80 kpa I'd try ~what I posted, keeping in mind if you can go leaner it might need another degree or so.
Keep your eye on cht.

I know this was a while ago (found it in one of the threads above that was posted), but just wanted to get a different take on this. I know we are supposed to experiment, and every motor is different, but Mario suggests that 15.1 is about as hot as can be run. Obviously this doesn't mesh with what Pile is saying. Maybe the 15.1 was assuming a distributor? Max advance of ~ 40°?

MarioVelotta wrote: ↑Mon Sep 06, 2010 3:09 pm What wideband are you using to target with? Most of your NA map is 15:1 that is about as hot as you can run! I hope you are running really advanced ignition with that or are monitoring EGT so you don't do damage your engine. From what I have found my engines have really like a mixture of 13.5-13.8 most of the time.
...my .02

Running too retarded is far more likely to do damage at low-medium loads.
Retarded timing causes high EGTS, too much causes low EGTs.
3 degrees retarded hurts efficiency greatly.
3 degrees advanced hurts a little.
we are talking about cruise here, not WOT.
No knock no foul.

A motor with poor cylinder to cylinder balance or poor fuel atomization may have issues hitting >17:1.
17:1 should not be a problem for a port injected motor unless something is broken.

I've wound a few more degrees of ignition advance into the table and adjusted a few other things. I also topped up the gearbox and re-greased the front end this morning.


Got my young guy clued up on how TS works. Hopefully all goes to plan. Might go for a drive now and get autotune started.

Just went out for a drive...
No CHT issues from what I can tell. As you mentioned, you have to bury your foot to get it to run that lean. Could be interesting driving for 3 hours with a touchy throttle and needing to put your foot in it. Other thing I noticed was, it transitions to boost VERY fast. There's also a bit of hesitation generally, but it's so strong and feels effortless on or off boost.

FWIW I decided to bump it back up to 22:1 again in the cruise area, ran VEAL on hard for some fine tuning, also logged it, ran great.

Interesting tidbit:
at 60-65 MPH cruise, using the "instant MPG" calc in MLV I was showing ~22-24 MPG on level.
At 75 MPH I got 33-35, and used less TPS and lower MAP, also straight and level.
(it was also running ~5 degrees more timing due to lower MAP, still 22:1 AFR)
It gets really happy around 3400 rpm.

There's something in the engines tune (mechanical---exhaust/intake/cam tune/target AFR/timing) driving this.
I need to figure out what, as I'd obviously rather get 33mpg than 22... It may be more efficient at different AFR at different RPM.
Likely. even...(historically it gets about 27mpg on e10, but has done 35mpg on long ...high speed trips, so it jibes)
I need to set up a gauge in TS to sort it out.

I've been tinkering with this stuff this week too. Been targeting 17:1 with a max timing of about 41° BTDC, the car drives along just fine, i feel the slightest amount of surging if the afr goes much leaner, could probably use a couple more degrees. EGT, and head temps are down a bit. Oil temp came down about 15°F too. I haven't really dialed in the timing yet either. The map is pretty boring, basically from 2150 and up it is at 17:1, with 42°(curved based on ethanol content) for pretty much everything other than full throttle stuff.

Ha, seems Pete got all of us looking at our tunes again. I also updated my tune, and tried to go for the 17-17.5:1 area as chip mentioned, with several degrees more timing. Set it up this morning and autotuned on the way to work. I felt like the car drove great, but I didn't really get much positive feed back on my CHT gauge (I have the VDO gauge, so while it may not be accurate numerically, it still adjusts up and down quite quickly to show change in temps)...still seems to be running a little hot. Keep posting away Pete, seems this is motivating others in their tuning. I know its helping me.

... I know this was a while ago (found it in one of the threads above that was posted), but just wanted to get a different take on this. I know we are supposed to experiment, and every motor is different, but Mario suggests ....

We all have a lot more tuning experience in the last 7 years.... opinions may have changed.
Marios in particular as he does it for a living to some extent now.

On my VE map the cruise area is really small since I go from 20 KPA to 260 KPA. I really need to get my dual tables working......
I have tried the 17:1 cruise and just don't like the way the pedal feels when the engine has to work to run that lean.

My buggy is not made for mileage so I stick with 15:1 or less usually and transition to 12.5:1 once I go to 100 KPA. After 150 KPA I am richer than that.

I cruise at around 60-70 kpa at 2200-2500 rpm and have my timing at around 34-36 degrees.

If I ran 17:1 with the throttle open that far and pulling 80-90 kpa I would have no transition area.

Piles setup works for him on a N/A type IV engine...... that is not what my turbo engine is about.

I am more concerned about keeping my engine from detonation or detonating....so to speak than squeaking the best mileage out of it.

I actually got almost 30 mpg on my trip to Big Bear so I'm doing ok I feel. At that time I was at 3500 ft or higher.

I usually average about 24-26 mpg around town and driving to work and back at 10 miles each way.....hardly enough to get it fully warmed up........

Just got home about an hour ago. Got a big report. Hope to have time to post it later... Pretty happy though.

Ok, something in the way of a report. I have somewhere in the order of 5 hours of datalogging and autotuning done over the past 2 days. Basically, once the car was warm, the autotune and datalogs went on, except for 2 trips this morning. But I digress...

My past attempts to drive to Canberra or near there in a beetle have been expensive and painful. The first, some 15 years ago wound up in a ruined motor thanks to not enough tinware (newby fail). The second one 2 years back resulted in another cooked motor when the rocker cover gasket tanked on a 100degF day. I got home on the motor... just. So I was having a minor anxiety attack all week. I packed copious amounts of tools, a tarp, a jack, trans and engine oil and overalls. I figured, if I took it all, nothing would go wrong. If not, everything would go wrong. The good news is not much went wrong. We drove about 650km and used something like 40L of fuel (I'll confirm that later) and a little engine oil.

We left later than I'd hoped on friday night and got stuck in traffic for the first 40km or so. After that it opened up and was better. Initially the plan was to sit on 60mph and just try and get a good tune using PD's AFR suggestions. I also wound more timing into it on thursday night. I was still terrified something would go wrong so I was taking it easy. We topped up the fuel tank at Goulburn. It was pretty cool then (around 10degC) but then it got a lot cooler. Pretty much ideal for the AFR experiment I was conducting. The head temps at 60mph were high 60s to low 70s Celcius. Intake temps sat between about 32-40degC cycling up and down depending on hills and boost. The closer we got to Canberra, the faster I went. I noticed it was quite happy at 70mph. However, it was late and I didn't want to break down or similar, so I slipped back to 65mph. I had a few times with the WB went dead lean for some reason. Dunno what that was all about? I wasn't datalogging though coz the laptop had run out of battery. Didn't do it on the way home.

We got to my brother's place around 7pm very relieved. They let me park in their carport, which has a nice dirt floor for soaking up oil.


A couple of initial impressions that proved true for most of the trip.
1. It leaks oil and burns on the headers. Yuck. Got over that stink real fast.
2. The roller throttle is not a lot of fun. I had my work boot jammed in a good spot to cruise with but it wasn't great.
3. It's Insta-boost. Just rolling into the throttle a little on a hill, the car instantly went into boost and didn't seem to want to climb at an even speed. So I was off and on it. It's like a switch.
4. The initial autotune pulled a LOT of fuel out of the map under 92kpa. It then fattened up the 92-110kpa range a fair bit.
5. The inside of the car is quite loud. We both wore earplugs on the freeway. I think my ears are still ringing anyway.
6. The freeway is pretty rough. Especially in an old VW. I was bouncing around in the stock seat.

It was pretty cold this morning but the car started ok. I did my work thing today and then went to a lunch. I have to say, I was pretty disappointed with Canberra roads. Very rough and poorly maintained. The people are nice though. Afterwards our engagements, we hopped back in the car (put in the plugs) and left for home... Here's my navigator.




He did a pretty great job turning the various things on and off and helping me. Here's his best shot of me.


Yeah, good one! Not.

On the way home I was planning to fiddle with the timing a bit and try to maximize things, but to be honest I didn't think it needed it. We set the autotune to "hard" and datalogged again. This time I sat on 70mph (3700rpm) to try and get a good tune at that speed. Again, effortless. I was overtaking people at 75mph. More insta-boost, stinking oil, low CHTs and the like. The CHT came up to 75degC when the sun came out momentarily. I started to panic and then remembered, "it's freezing outside you idiot". It couldn't have been much above 10degC all day if at all.


We dropped in at my twin brother's place in Goulburn. He was trying to deal with a fuel filter that had cracked and leaking everywhere. I took him for a spin, but the car wasn't going quite as hard. I think the intercooler was a bit heatsoaked. I had a cuppa tea and then we headed for home after topping up the tank and checking the oil. Then more datalogging and autotune. We got home about 7pm.

I've got a week away this week at a work retreat. I'll go over the car when I get home and seek what's leaking. I thought the trans might leak, but couldn't see any evidence this morning before we left. I might have a chance to sort through my datalogs and post some pics of them. Lots and lots of info and I'm a novice.

Anyhow, I call it a success. I don't think I want to do it again any time soon though. I am curious to see how the car will deal with hotter temperatures after tuning it in such cold temps.

Sounds like you guys are having fun with your tuning, and congrats on making it back and forth from Canberra. Nice to get that little round trip gremlin off your shoulder. Cruising at 70mph sounds great. I hope I can figure out a tune that grants me that power
Any way I could talk you into getting a CHT gauge that mounts to your spark plug and sits on the head? Just get a cheap VDO one like I have, then you can really see the head temps fluctuating in real time. I think I asked you this some time ago, and you just have the one that Mario sells and mounts to your tinware. That one is great, but I believe it is more for warm up procedures (i.e. coolant temp sensor), and I think it has a little more trouble giving a real time temp, as it takes a while for it to heat up and/or cool down.

If it is the sensor that screws onto the tinware on top of the head its only useful for WUE.

My CLT is an open element sensor that is close in and directly in the airflow through the heads exhaust area, and I know how its readings correspond to under-the-plug CHT.
(T4 heads have airflow there, T1 not so much due to port design, but there is airflow over the center of the T1 chamber)

To read CHT, I plug the sensor into my DVM, which has a temp compensated TC input.
The CLT and CHT track with an offset based on fan RPM/airflow: At idle its virtually 1:1, at ~3300 RPM cruise the CHT reads ~75F higher. You may be able to get an inexpensive industrial TC gauge with temp compensation to get comparative readings and keep in the toolbox when not in use.

Note that in winter (under 70F), I revert cruise AFR targets to ~stoich or it runs too cold, even with a working tstat setup.
You may not have to do that.

I has a TC input on my first MS2 rig but it was only useful for EGT, due to noise on ground.
The EGT sensors are insulated from ground.