www.RX7fb.com

Will get screen shots of the changes it makes next time I've read your post just too late as I've just manually been messing with the map!

Tunnerstudio does a pretty good job of fixing the fuelling map, when I was out driving earlier I had it set on 'easy' changes, so it only has to see that a particular map cell is out once or twice before taking action then every time I got in to a part of the map that was poorly tuned I just keep the engine in the place and within 5-10 seconds it had sorted itself out to within 1 AFR of where it was meant to be. Once the whole map is fairly close Ill turn it up to 'medium', then 'hard' and just leave it thinking in the foot well while I go out for a drive.

It's not a totally perfect system though. The tunerstudio auto tune feature creates maps that often look lumpy and messy, rather than the super smoooth curves that should be theoretically correct, but they do normally drive well and don't feel lumpy. You've gotta take the car to all it's extremes while driving on public roads, so that includes awkward areas like foot to the floor and idle while under load, right up to cruising at 7k (from experience you get odd looks going along the motorway in 2nd at the redline for a few miles to tune in that part of the map!) Normally I let it tune me in fairly close then go in an manually massage the map, smoothing out any anomalies.

Finally there's one situation that totally baffles the auto tune. If the map is so rich that the engine misses, then there will still be lots of oxygen in the exhaust as its not been burnt. The o2 sensor sees this and says lean, then tunerstudio adds more fuel and it gets even worse! Normally talking richer than 8:1 AFR to do that so not too common.

In fact Ramo the way to look at it is that in a 20 minute drive tunerstudios auto tune took me from a base map where the idled ok but bucked and popped under more than about 10% load, or at any rpm over 2500, to a car that essentially drivers reasonably normally without me having to do anything but drive the engine across its working range.

It's not the tool for making the perfect map, but for doing the ground work and getting the basic shape worked out its really good and very quick.

After a fairly manic week, I had an afternoon off today to sort some of my snagging issues out.

First off my interior lighting issues turned out to be a fuse and the electric window I'd forgotten to plug back in So they were easy fixes!

Next up was to raise the rear suspension a little. Having dropped it ~25mm when I moved the suspension mounts it was now nose high and I didn't want to lower the front any more as it would really start to compromise the amount of travel I've got. Only too a few minutes and now she's sitting really nice and flat, trim heights of 310mm all round.



Whilst I've been working this week I have managed to take her out for a drive over a few evenings and made a little progress with the tuning. With a bit of help from the datalogs I discovered a couple of issues. I was having a few sync issues between the CAS and megasquirt even after re-routing the cable, so I changed a smoothing capacitors value and thats done the job. I also finished wiring in the old choke magnet to megasquirt so my high idle is semi automatic! This means she's spent all week looking like this:



So I spent a hour or so tidying up then finished mounting the Megaview. It's not as clean and neat and tidy an install as I'd hoped but for now it's functional.



In the radio space is the Megaview with its function buttons that gives me data readouts from all the main ecu sensors and outputs, it also allows me to make basic changes to the MAP, kinda changes that mean I can limp home if needs be it doesn't replace the laptop for tuning. Below that in the old cubby hole is the oil temp and the oxygen sensor reset and status lamp.

Finally all the tuning I've done this week has been pretty much wasted as I only just realised the throttle stop is fouling the throttle cable so IO was only hitting about 85% throttle.



So I sorted that. Roll on 100% throttle!

I'm hoping to sort my trailing coils in the next couple of days so then tuning can begin properly, for now I'm just trying to get it somewhere near across the whole rev & load range, as there were some rather large holes in my base map!

I got some screen shots for you guys. This is the fuel ve table that I started with. It's rpm vs load%, where load% is essentially a combination of the manifold pressure and the throttle position, but exactly what balance varies across the rpm range and is set in another table.



After about 90 mins of driving with the auto tune feature on and the change resistance set to 'easy' ( and plenty of backfires, pops and flames) it was looking like this.



As you can see its quite different and the general shape resembles what I'd expect from a blended tuning mode table, but there are some nasty holes and lumps too. Some of these are areas I simply didn't get to drive in during my 90 mins. Other areas such as the over rich area above idle will never tune great with auto tune. In normal driving I'm only passing those cells while free-revving away from idle before putting the car into gear, so if the o2 is reading lean it probably means I need more acceleration enrichments (equivalent of accelerator pump on a carb). On the other hand if I'm only ever hitting that part of the map in that free revving situation then it wont matter and if ii were never to study the VE table itself I'd never know there was a problem.

So what I normally do is a bunch of auto tuning then come home and manually smooth the map out a bit, till I end up with something like this.



As i said previously in this post, all that was done with the throttle not making it fully open and the sensors calibrated as if it was so it's all a bit irrelevant now.

One thing that is interesting is that I've been doing some ignition timing research and found a number of sources showing the supposedly very good base map from the Apexi Power FC for turbo II and FDs and they all look something like this. (ignore the blue and red numbers thats telling me whats recently changed and it's gone wild because I've loaded a completely new map in!)



Where looking mainly at the 100% load row (WOT) the timing increases fairly linearly right up to 39 degrees BTDC at 7500 rpm. Now the maps I've seen most Megasquirt guys use look more like a direct mapping of the timing the distributer would produce, where the advance at 100% load levels off at around 24-28 degrees at 4000 rpm and increases no more to the red line.



I've had a play with both and the Power FC style map does feel better, but I'm cautious about running that much advance and for the moment till I sort the trailing coils for a decent set it's just wasting my time to do any more on it. I will be sure to get dyno comparisons of the two base ignition maps though when I got her on the rollers.

Been out for some more of a drive and playing with the spark tables, the Power FC style table definitely feels better at low revs, but it feels no better at 4-6k and at 7k it doesn't feel as good.

So I've gone back to the dizzy based map and given it some extra advance at around 50-75% load and 1000-3000 rpm so the shape matches that of the PFC and it feels pretty good for now. I shall leave it alone now till I'm on the rollers with better trailing coils.

Ian was kind enough to give me some more coils so now I'm running a full set of 4 FB coils. I modified my little coil tray to use the original FB style brackets and it looks reasonably neat still.





The tuning has been coming along slowly but surely. The full throttle stuff is pretty much done on the fuelling side, its the smooth cruising and transitions that are more tricky. Smooth driving isn't helped by how sensitive the bodies are at small throttle openings, I'm considering trying to make/modify the throttle linkage to give me a larger pedal travel and lessen the sensitivity. Next up on the tuning front is to get some dyno time sorted out.

In the mean time I went for a drive after work today and took a couple of photos and a small video clip with the help of my sister.

http://youtu.be/hZM-oQ7p9Bg

The vacuum is fairly stable for now, but with the ITBs its only pulling 50kpa of vac at idle and at about 10% throttle at low revs its already reading atmospheric, which leaves a big whole in the map really for 10-100% throttle at low revs. The beauty of using this hybrid alpha-n tuning method is that it basically means I use speed density till I reach only a few kpa of vacuum then it switches over to alpha-n.[/quote]

Is it just me or is this some foreign language I have not come across before????

Thoroughly impressive Steve.

.... and Good Luck!! (whatever it is you are talking about..... )

John

Good work Steve! Nice video too, good too see it in action.

Don't get disheartened Steve!

I am currently doing some work on low carbon vehicles with a company called Ricardo, and I spend my days with their engineers. Their guys are literally the best in the world and have an average of two degrees each (not exaggerating - we have a few with Physics or Maths PHD'd who have Engineering MSC's as well which ups the average....). To brag even more, these are guys who designed and developed the drive train for the Bugatti Veyron and who developed (and now manufacture) the engine for the new McLaren sports car.....

They are routinely faced with problems just such as yours (see "sartre"project videos on Utube...), and have to spend hours researching and thinking of options and possibilities. Listening to them is just like reading your posts. You are overcoming the same day to day problems of any leading edge automotive design engineer working on electronoc control of a car, and you are doing it without a team and without a multi million £ budget...

Keep up the good work!

Cheers guys

I'm not sure whether to take it as a compliment or not that I apparently sound like scientist when I'm trying to make my career in the arts Still tuning super cars would be fun! They don't need a new apprentice do they

Your project development is mind blowing Steve.....fabulous stuff!