Romans COD piece

[Roman]

And yeah ill chuck it on the dyno once ive had the exhaust redone. wideband in the tailpipe wont tell much with the current number of exhaust leaks haha.

ive heard of guys with altezzas trying to use piggy back computers but then after a week its back to exactly how it was before when dynoed again. so its more than just adjustment at low load. and the long term fuel trim values i can see back that up too.

[ProZac]

All modern EFI ECU's use short and long term fuel trims, they have hard limits though, where they reach the end of their allowed adjustment. They're put in place to allow for stuff wearing out over time, not for modification purposes. Your injector results are pretty cool though. It won't be changing values in the mapping, but as the final desired fuel value uses the long term fuel trim as one of many factors, and this is stored when you turn the car off, you should get pretty consistent results. I suspect, however, that if you remove your battery lead for a while, and reset your ECU, you'll be back to square one, and it'll take time for your fuel trims to adjust again.

 

I lost pretty much all respect for NZPC when they ran that article of the fireball Altezza from Christchurch that burnt up on the hills. That car had no business being anywhere near a magazine, or a road infact. Although the article did raise concerns about using the stock ECU on a supercharged engine, you can just bet people are going to try it, and it's a fucking stupid thing to do.

[Roman]

All modern EFI ECU's use short and long term fuel trims, they have hard limits though, where they reach the end of their allowed adjustment.

Yes, but until now it's not been entirely clear how it functions. The hard limit each way is 20%, as per what I found in some OBD documentation and this also correlated with the fuel pump problems causing a 20% raise in injector duty cycle. Which was the upper limit.

 

 

 

They're put in place to allow for stuff wearing out over time, not for modification purposes. Your injector results are pretty cool though.

Of course, but it acts in a predictable way and I've now got realtime information as to what exactly it's doing.

So not only could I plan modifications around how it operates, but I can also get feedback of exactly how it behaves in response.

Rather than pumping assumptions into a magical box and hoping you're correct with no actual feedback.

 

It won't be changing values in the mapping, but as the final desired fuel value uses the long term fuel trim as one of many factors, and this is stored when you turn the car off, you should get pretty consistent results.

The way the fuel trim works based on observation is that it changes based on rpm and load, rather than blanketly smothered across the fuel map.

So it effectively acts a secondary table that's plonked over top of the first one, with adjustment values for different areas of the map.

So the net result is a +-20% allowance in injector size, apart from if running 20% smaller required over 100% duty cycle to not run lean.

 

 

I suspect, however, that if you remove your battery lead for a while, and reset your ECU, you'll be back to square one, and it'll take time for your fuel trims to adjust again.

Yes, this is exactly what happens. I'm fine with that.

Regarding the standard ECU thing, I've seen a few really clever ways to retain them and work awesomely.

My favourite was a 5EFTE(?) powered starlet which was NA converted to turbo - They put in a new map sensor that had twice the pressure rating of the old one, and also fitted injectors twice the size. And the ignition was either mechanically controlled or retarded to suit...

So the engine thought half as much air was coming in, so put in half the amount of fuel... Which turned out to be exactly correct.

Some may say that's a bit of a bodge, but if it works well then it's actually pretty bloody clever!

[ProZac]

Did starlets have a MAP sensor, even in N/A guise?

 

That method might work, and run, and maybe even not blow up, but would be far, far from optimal. The different injectors fitted most likely had different opening and closing times, which have a pretty big influence on cruise and idle running. They must have also fitted a rising rate fuel pressure regulator? All the computer controlled enrichments that aren't referenced to the engine load map (map sensor), such as throttle tip in, cold start, a/c and power steering load adjustments would be totally out of whack.

 

It also relies on the fuel requirement being linearly related to the manifold pressure. TBH I dont know if that is the case, but I would be surprised if it was that simple.

 

But if it works for them, and they're happy with it, more power to em'.

[kpr]

yeh all injected starlets are map

 

4afe +t  with  gt starlet map sensor and injectors was another one.  maybe with an afc to trim  fuel where needed.   

 

^aint gonna be any worse than most carb turbo setups out there.

[kyteler]

Yeeeeeeeeeeeeeeeeeeeah booooooooi.

Looks sufficiently rapid, sounds dorty. Well done Row Man.

[Vintage Grumble]

Yes, yes, very nice.

 

Do you planning on doing any of the dual sprints Taupo do over winter?

[Roman]

Hmmmm, dont know too much about the dual sprints, I dont have a racing license or whatever. Or any real intentions of doing any real racing lol.

 

Next trackday on the menu will be the Toyota 86 festival or whatever, at Hampton Downs in May.

 

Cant wait for a burn around that track!

 

Havent been yet.

[Brennan]

Looking good. i would definitely recommend traction brackets ASAP.

Putting traction brackets on mine helped so much i couldn't believe it.

Before it felt underpowered. Now it is well past having traction and lets loose very easily.

With T1R's

 

I need a lsd now.

[Roman]

I'm hoping to acheive the opposite with traction brackets hahaha.

 

Currently the car can only put down probably like 50-80hp before it spins the wheels in first or 2nd gear.

Sounds fun but when you try to pull out of a side street into a gap in traffic and just blaze the wheels eeeevery time and dont move it gets pretty old!

 

My lower 4 link arms are *just about* level, they currently point slightly upwards towards the diff.

 

With traction brackets I should be able to get them pointing down towards the diff instead.

Which should push the diff down into the ground on accelleration, rather than lift it up... hopefully!

[kpr]

brackets will give you plenty more grip.  long as you don't drop the links too far, as will start to roll steer.

[Roman]

OK thanks!

 

I dont expect it to be a quarter mile champion or anything, but it's embarassing that my Toyota Echo would probably drag it off from the lights at the moment haha.

[Celica RA45]

are your 4 rear links still std with rubber in them or have you gone to nolathane ?

also on the front try 2mm toe in/ 5,5 caster if you can and aim for about 3neg camber

also shitty hard tyres will make it break traction .a nice soft tyre will change it,oh so much better

try a 24mm fully adjustable bar on the front good set of shocks i prefer bilsteins about 250 to 275 is ok for road and about 200 on the rear with no rear sway

[Roman]

Yes standard rubber in the rear, apart from the panhard rod which is rose jointed both ends.

Tonight I added what I will assume is 2 degrees of  camber to the front, and went for a bit of a doort.

 

Steering is back to being good with a little camber now! And it doesnt hit the gaurds at all with the wider tires.

 

My 0-100kph time is probably half of what it was a week ago... Just a quick chirp then it's off. awesome.

My shocks arent anything too fancy but my front to rear spring rates seem okay at the moment. Dont really want to go any stiffer on springs, might get some better shocks one day though.

 

After driving it tonight I dont think a rear swaybar is required, it's handling great.

[Celica RA45]

just make sure that the rear 4 link rubbers havnt chewed out with all of that power

also try this, put car on a 4 point drive on hoist undo all bolts to trailing arms then retighten

im also using 205x50x15 and have no problems on the front have 225 on the back thou

[kpr]

those t1r's should feel better once they wear down a bit.    new, they squirm around a lot.

[Roman]

Yeah I didnt notice that last time I bought a set, (On MR2) but they did feel a bit squishy on the Carina until I added the camber.
 

It's kind of like going from an old set of skate shoes where you can feel everything, to full soles again. Heh.

Either way, gave them a bit more of a scrub tonight around scenic drive and the car is going sooooo good!

 

4 weeks till Taupo trackday, if it's dry I'll definitely smash my 2.03 Carina lap record and hopefully come close to / beat my 1:57 MR2 record on full track.

I've had a moment of clarity about a few corners I've been doing wrong as well, and will bring a pyrometer to bump the camber in or out a bit on the day depending on what the tires are doing.

[Truenotch]

Remember that bumping the camber will likely change the toe settings too though. 

[Stu]

Nice work with the knock sensor! Still rolling stock ecu I take it? Using torque app via obd2?

[Roman]

Yeah, stock ECU.

 

Torque is such an awesome app!

 

I've got a few different screen presets setup which are handy.

 

One I use when I'm trying to be stingy driving my Echo, with realtime and average fuel usage values, a tacho and one or two other things.

 

However I've got a few other screens with like ignition advance, intake temp, coolant temp, tps, etc etc which are infinitely useful for troubleshooting and figuring out what the ECU is 'thinking'. Even if you use only one gauge it doesnt really update quick enough to be used in realtime as a tacho or whatever though.

 

I've found that in any car that I've driven, about 80-85kph is the most economical speed... It's the cross over point between keeping engine rpms low in top gear, aerodynamic drag and keeping the speed high for the amount of fuel you are using.