Roman

It was coming up to dinner time last night and I was mucking around on the laptop Girlfriend: "Hey, how much longer are you going to be drawing graphs in that program for?" Me: "About 20 years" Girlfriend: "Okay"

If you dry sumped it, could you lie a rotary engine over on its side? Seems like a good idea to have the inny/outy parts on the top of the engine rather than crammed around a steering column.

That's a given! Myself and Dad are both heading down from Auckland, most likely in two seperate cars (Carina + JZX90) Not exactly sure on our plans but you're welcome to tag along with us if you can knock off work early on the Thursday. (Leaving akl about 3pm) But not sure if I'll stay for a few days or drive back up (or catch bus home again lel)

Lack of mufflers was not ideal. Side pipes are great though. Keen to try catch up to your Taupo laptime, you've blitzed way past me now.

Says the guy who likes Cheviot Turbos

FD is such a beautiful car. I'm not saying that it's a "pity" that it has a rotary engine, but it's certainly a pity that some people dont like it just because it does.

I've been having a bit of a think about compensation tables lately and how to build them in a meaningful way. I'm not convinced that the default IAT compensation values necessarily suit my engine. But It seems quite dififcult to know how to change it and check the results. But I came up with a good plan. (maybe) Instead of mucking around with the IAT compensation table and randomly changing values. For now I've just turned it off, and all other comp tables. So I'll get the car as heat soaked and high temp as I possibly can, so that the temps of everything are already stable on the "high" side. Then run through my map and get fuel values spot on as best I can. Thennnn let the car cool down completely, start it up and start a datalog once the engine temp reaches say 85deg. The drive around for ages and build up a big datalog file of how the fuel changes over time on account of heatsoak etc. I can add a second fuel table that's an overlay of the main one, and that adds or subtracts from the main table. Buuuuutttttt the interesting part is that it doesnt need to share the same axes on the second table as the main one. So for example my main fuel table works based on rpm and MAP sensor. However on my secondary table I could have it working based on RPM and engine run time. or IAT and engine run time. Or RPM and intake manifold temp sensor readings (if I had one) Or whatever else. Instead of needing to figure out how to build this map. (and whether it makes any sense) I can load the datalog file and use the mixture map table to build the overlay map to fill the 2nd table in. If there's a genuine trend happening, you'll see it in the shape of that overlay map. If it's just random spikes up and down, then I'll try something different for the axes and rinse repeat until I find what it is that causes the trend, without having to run the car at all until I've convinced myself that I've made a worthwhile comp table. Then if this works, I can run the car with that comp table in place and do same thing again to build up the next comp table on top of that (if need be)

Their gas consumption was pretty high in the 1940s.

At first I was like "Why the hell would you go to all of that effort to end up with a weird liveaxle/non liveaxle thing instead of proper IRS" But then realised it had a whole heap of scope for adjustment on all of the suspension links to adjust roll centre, traction from link angles etc that you probably couldnt do with a mac strut or whatever. I dunno, maybe it was still a well engineered stupid idea. But it was definitely something unusual that caught my eye.

Yeah the factory IRS isnt toooooo amazing in these cars. It would be nice to be able to adjust rear camber to keep tire temps even at trackdays though. But it comes with a whole other set of foibles due to lots of toe change through suspension travel etc. Although its less unsprung weight, it's heavier overall compared to live axle. There's a really interesting race car that I saw in NZPC ages ago, it was like a modern Mazda 6 or something converted to RWD. It had a solid beam rear end with a watts linkage, but the diff head was mounted to the body and it had CVs on the driveshafts which lead to the hubs mounted to the solid beam. It was like a live axle setup but with none of the unsprung weight of the diff head.

That side pipe wasnt ideal haha. Cool man, hope you can make it along!

Something interesting about driving with a live axle that I've noticed over the last while. I start going into a corner and the car will roll a bit. But then as roll increases I think the shock on the inside reaches its limit of travel and you can feel it start to pull the diff up off the ground. Something like this It feels like the cars rear roll centre is at the centre of the car to start with, then moves to the outside wheel once the inside wheel starts getting pulled up off the ground. But it's two very noticeable characteristics before the car will lift and inside wheel or start oversteering. You can feel when the car gets to that "wheel lift" point (and try keep the car below that point) well before its lost traction or anything like that. IRS is for quitters

Doooo eettttt Tow the AE86 with your Hilux, then when the hilux blows up on track tow it home with the AE86.

I'm heading to a Taupo trackday, full track on Friday September 2nd... Only $150 for a full day of hooning around! Generally only 25-30 cars total, so the tracktime you get is HEAPS compared to any other event I've ever been to. Anyone else keen to come along? Would be cool to have some other OS peeps there. See link below for details, you just need a car with wof/reg, overalls, and a helmet. It's not a drift day though. If your car lacks wof/reg because it's a dedicated track car or whatever, not necessarily an issue but just need to discuss with the guy running the event. (It's generally fine) http://www.gpforums....s-all-booked-in My old man is gonna bring his JZX90 down for a hoon around as well. Get amongst it!

The time difference of response is bugger all. As an example. A 2000cc 4cyl 4 stroke engine (if non turbo and 100% VE) inhales 1000 litres of air per 1000rpm. So 7000rpm = 7000litres per minute. 2 litre plenum = under 20 milliseconds to empty. A 20 litre plenum, which would be rediculous, (size of 10 milk bottles stuffed in your engine bay somewhere) would still only be 200 milliseconds. A 1.6 litre engine will be 0.8x the times listed above. Human reaction time if you're wired on coffee is just under 1/3rd of a second, (300 milliseconds). You're not going to notice any difference in sound, because all of the sound waves are happening between the plenum and turbo outlet rather than exposed to atmosphere with NA car. Single throttle will be easier to tune as you get a more stable MAP signal, personally if I was going ITB turbo I would fit a MAF Sensor if off boost drivability etc is of concern.

What was it previously?

I finally got my new wideband installed over the weekend. So switched over to modelled fuel. (This models the engine size, injector size, air mass, AFR goal etc etc as part of the fuel equation rather than just numbers on a table) First thing I notice is how stupidly fast I went from nothing to having a mostly sorted fuel map! I believe the numbers in the fuel table represent the engines volumetric efficiency at each rpm/load combination. Which makes it easy to make a base map because for an NA engine you set the WOT row to 100% efficiency and then just drop the numbers down the rest of the map and then interpolate it. Doing this, I had a drivable car that didnt buck or run crazy rich/lean even before I'd driven it. Some spots were quite different (Idle area 70% efficiency at high load, and the peak torque rpm area was about 115%) One thing that's cool that I noticed, is that there is a table with your goal AFR is part of the initial fuel equation. So once your numbers are correct, it's super easy to adjust AFR because you just raise or lower the AFR goal. Rather than, having to adjust an arbitrary number in a table up or down in every cell via 02 feedback, and checking what AFR that results in. Also the engine seems to run smoother for some reason, possibly that this is more accurate lambda readings from the sensor now? Maybe I was previously actually running leaner or something like that. Not sure but it feels really smooth and sounds good which is cool. Running only open loop and tuning just with the Mixture Map I very quickly managed to get a most of the low load cells to a stable 14.7 in a very short period of time. The fuel economy information is dissapointing though, it just gives cc per minute rather than l/100 or k/litre or MPG or whatever. But this still makes life a lot easier. I remember the first time I tried running on modelled fuel setup, it was a total disaster because I had so many of the background settings wrong. But its one of those things, when you've put in the groundwork ahead of time the rest just falls into place. Looking forward to some more tinkering this week!

Does this work for vacuum leaks though, or only boost leaks. Wouldnt the bubbles be happening on the inside, haha.

Oh man I would be super keen for a holiday to Nelson! <3 South Island. Do you have a spare injector, the same as what's in your car? If so, send it up! and I'll test it for you.

I think it's mainly to extend the pumps life and also yeah to reduce cabin noise from the pump.

I dont think it really matters, because the fuel pressure reg will hold at a particular pressure so you never get it running too high. As Speeno says some Nissans etc run a resistor in the fuel pump circuit to run the pump at half voltage when under low load. My fuel pump whines like crazy when I had the car set to ~80psi, it was the restriction to flow that cause the pump to load up. Now running at 60psi and it's much happier. If I ran my engine at ~40psi I'd probably see consistent fuel pressure at a lower pump voltage again. As it might need to drop to 7 volts or whatever before it drops below 40. In my mind though the #1 thing relating to idle and fuel is dead times, because the actual deadtime is a huuuugggeee part of the total injector opening time. As in, deadtime could be 5x the actual time that fuel actually comes out while the injector is open. If your deadtime is inaccurate then if you've got any temp compensation etc going on, your fuel at idle is gonna be a mess. My idle has tidied itself up hugely since having accurate deadtimes.

Low fuel pressure from low voltage definitely changes things. That's where I start to see the deadtimes being way different to factory figures, because in a real life scenario when your injectors have 8v so does your fuel pump so the pressure drops. Below about 10volts on my car, and you start seeing fuel pressure taper off. Wideband fuel trim cant really do much at idle sort of speed, I dont particularly trust my widebands readings at idle anyway. Because the motor will be running visibily rich out of the exhaust but it'll show me everything is dandy at the wideband. Maybe I've got a small air leak somewhere. My new wideband controller should hopefully be here tomorrow, woohoo. Feels like flying blind having gone a few weeks without one when I want to tinker with stuff haha. Looking forward to having a bit of a tinker with injection timing at cruise conditions. Also now that my deadtimes are good. Seeing if my outer injectors now do anything useful below ~5500rpm.

No worry, can always fit an SW20 gearbox later on if need be.

The fact I'd be getting a bargain as well as fuel economy, adds an explosive exponential growth to the smugness. It's hard to know exactly how smug because I'd probably have passed out by that point.

Dang that's gotta get you right in the feels.