Roman

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.

So I pull up into a carpark somewhere today, 4.1l per 100km for the trip so I'm just sitting there being a smug prick like I've just saved the world or something. Parked up with my window down. Some young random labourer dude in the van next to me caught a wiff of my smug stench and goes: "That is the gayest car I have ever seen" I cracked up, surprisingly it's the first time I've been randomly insulted about driving an old ladys car. He looked so disgusted hahahaha. If only he knew... IF ONLY HE KNEW!!!

In the scheme of things its cost neutral to buy a standard motor to get it going. Because you sell it again when you swap the good motor in. Biting off more than you can chew is the #1 reason why projects fail.

My thoughts on an MA61 roof wing are that they are disgusting haha. Since you bring it up though. Based on a fairly shitty model that I've drawn. One of the main airflow streams starts on the outer 1/3rd of the front bonnet, avoids the windscreen altogether and tucks under the side mirrors and then curves back up and over the side of the rear hatch. It seems like the air wants to go around the sides rather than over the roof, where it can. My initial thoughts are still that a roof wing or rear wing will acheive pretty much nothing. Looking at the car in plan view, an absolute shitload of air gets pumped through the wheels to escape the engine bay and trans tunnel etc which is good I guess. But the car has a very wide wake, starting right at the front of the car. With a model life this setup it's really easy to add a roof wing, or a front splitter, or a sharks nose or a whale tail, various other fish bits and see what happens. You can set a goal for the simulation to measure total lift and drag. What's interesting though is that it seems very hard to "win". As in, you do something to decrease drag but then you increase lift. Or vice versa. As an example, a shark nose helps the flow stay attached to the bonnet and gives a much lower stall point at the front of the car. But then all of this air hits the windscreen instead of just going straight over the top. So not sure if that's actually an improvement. Maybe more on this later if I ever come to any meaningful conclusions. I'm sick at home today which is causing some serious brain fade so no further comment until my brain is braining again. As this took way too long to write haha.

The factory twin headlight cars have their main indicators located in the front bumper. Because the front indicators are friggen tiny and I didnt want the ugly cutouts in my bumper, I replaced the front bulbs with super bright LED replacements and then found an aftermarket flasher unit that doesnt speed up when the resistance changes. Only downside is that it wont flash faster when a bulb is missing anymore. But you can get a flasher unit thats a plug and play swap for original one, it's in a bastard of a place somewhere near steering column under the dash though haha.

Twin headlight setup looks lush! But I would say that haha. 4AGTE will be awesome

Myself and Sentra Dave spent some time getting some data on ID1000s tonight. This was interesting because it's the first time I've measured some injectors which actually do come with some reliable deadtime info. For better or worse my results were very similar to the provided figures, we were running a slightly different pressure compared to listed data though. Unfortunately we found that the Link G4 does not appear to have a minimum pulsewdith setting, or a short pulsewidth adder table, so some of the extra lengths we went to by running lots of tests could have perhaps been streamlined a bit. (Sorry to chew up your afternoon Dave...) It was still interesting though and good to rule out the injector behaviour as contributing to idle issues etc. Also the injector behaviour was pretty good anyway. They were clocking in at 938cc @ 39psi / 13.6 volts. Nice and linear down to about 2-2.2ms but below that you really need the PW adder table as there's quite an agressive "knee" and then it drops off pretty quickly. This gives me some confidence that my method is pretty good, and it will work well in other cases when injectors are being used where accurate deadtime information just simply isnt available.

I dont have need for one personally, but could be interesting as a project. One thing though, if its for the Viva have you considered something like this? http://ecomodder.com/forum/showthread.php/how-get-instant-fuel-consumption-megasquirt-5474.html You'd need the laptop plugged in to see results, but its free which aligns well with our spending philosophies haha.

Haha crackup! This is kind of the flaw with measuring Coefficient of Drag, frontal area is part of the equation. If he's kept the same CD but increased frontal area by a fair bit, then he HAS increased drag. For the Kayak to be "cost neutral" he'd need to have ended up with a lower CD to offset the extra area. Not sure why he's bothered calculating CD anyway because solidworks would have given him the total drag number (which is more meaningful) in order to run his calculation with. His numbers are way off anyway, with a sanity check there's no friggen way a late model BMW has a CD over 0.5 It's a nice model of the car though! Wish I knew how to draw stuff that well in Solidworks haha.

No I cannot. Warmest Regards, RomanDave

Thanks man! That would be great.

Joker said in the fuel economy thread that waxing your paint can actually help marginally for whatever reason. It wouldnt make any difference to my bonnet or windscreen, as its completely dead air at this part of the car. But might make a slight difference at the areas at the back where flow detaches or reattaches.

Driving with the economy meter is interesting! Basically you'll be driving along fairly normally at say 70kph, the needle will be on say 7k on the tacho. as you slowly accellerate, the needle will drop and drop, and then when you get to a certain point it just stops and doesnt go down anymore. If you keep accellerating from there, the needle starts going back up. So once you get to that low point, you back off the gas to hold that speed, and the needle will drop down to say 2krpm or 3krpm. Whether you're on a hill, a downwards slope or whatever. Within the space of about 10 seconds you can find the most economical load and rpm combo which is pretty cool. It's amazing how deviating just a few kph either way of that point takes away economy really quickly. I found that my throttle was quite jumpy when trying to fine tune that needle angle, so I have revised my e-throttle curve to be even less sensitive below 70% throttle. I might setup a second throttle map so that if you ever go above 6000rpm, it will start a timer and switch to the "race" throttle map which is linear. Then if you havent gone over 6000rpm again in the space of a minute or something like that, it goes back to the mushy throttle. So congratulations to me, I've just figured out how to make e-throttle as unresponsive and mushy as OEM cars, the thing that everyone hates about it hahaha.

Haha, their "about" page cracks me up: Sucks when the market runs out of "greater fools" and you're the last one haha. Wonder how much they forked out for that.

I cant commit to a time for a west akl pre-meet this time sorry. Anyone else want some tyres or just pooman.

Ahhh one other thing. I made a table in the ECU that temporarily converts my tacho to a fuel economy meter. It's not as simple as just measuring injector pulsewidth, because you could have the same pulsewidth at a higher speed means better economy. So it uses some calcs based on injector pulsewidth, rpm, and vehicle speed in order to wave the needle around, it's a bit unnerving at first haha. But if the needle shows between 2-3k rpm you're doing good, and if its pinned at 8krpm you need to revise your driving strategy haha. Will be interesting to keep an eye on it on longer trips. I dont think it's useful for quantifying changes to the tune etc in the same way as taking averages from the logs though. I also found that I'm a bit of a noob and had my fan switch-on temperature and hysteresis set to a temperature where my fan would just be on all of the time. ha. So fixed this and now the fan runs only very minimally.

Coming back to this overly simplistic model I drew ages ago: As previously mentioned I've got a spare map sensor hooked up for datalogging (well it's not a map sensor anymore, just a pressure sensor) Tonight I thought I'd finally put it to use and see what sort of air pressure I'm getting at various points up the bonnet, up the windscreen, and start of the roof, and on the front bumper area. So, tape the hose to a certain part of the car, go for a run to 110kph on the motorway, log results, move the hose and test again. Results not as expected! Nothing I initially measured, varied by more than the margin of error of the sensor. As in, if it showed 101kpa when stationary it showed 101kpa when going 110kph as well. And yes I did double check that the sensor works haha. The only tests which showed any variation were taping the hose to the glass on the rear of the side mirror. (Showed a pressure drop, as expected) And having the hose in the rear of the wheel well area. (Showed a pressure drop, as not expected! Thought it would be high pressure area here) I saw more of a change in barometric pressure, than actual pressure variations across the front of the car. It may be that a more sensitive sensor is required like a 5kpa manometer or something, but then is it even really worth bothering about trying to change something if the pressure difference is actually so immeasurably low? I suspect that the rear of the car will be the interesting part for pressure drop etc, however probably what would be more relevant and interesting will be doing some wool tuft tests to see where the airflow detaches. Similar to this: I might need a volunteer or two to help out though at some point, to follow the car down the motorway and snap a few pics so I can see what's happening. Anyone out West Auckland interested in participating in some Dave Science? Disclaimer: actual scientific content may vary from advertisement

Haha, these two cars are the yin and yang of fuel economy.