altezzaclub

Looks like a lot of work in front of you- How much did you pay for it? A good rustfree car from inland is only around a grand, I've got my eye on a couple of granny-specs being driven by elderley people around Orange... I supose you'd have to respray it somewhere along the line and that is always expensive.

I'd expect you would need to weld a piece of sheet over the KE70 shock tower to spread the load out across the inner guard and down to the boot floor. If you look at the KE70 spring mount on the chassis it would need to be that thickness steel to take the expected loads. Another little trap for people who lower their car and take out bumpstops.. you can rip the welds apaprt when you coil-bind the springs on a bump. Even set up correctly on the rally Datsun we would sometimes pop the whole rear window out upon landing over a yump, the rear of the car would flex so much & the boot sag downwards.

Meh- I wrote a long reply and found it all in Wiki anyway! There's not much in it, but what Twinky says is correct, a 4AGE will be at home at higher revs than your 4AFE. 4AFE- The 4A-FE is different from the 4A-GE in terms of performance and power. Although both have the same displacement and are DOHC, they were optimized for different uses. The first obvious difference are the valves, the engine's intake and exhaust valves were placed 22.3° apart (compared to 50° in the G-Engines). The second is that it employed a "slave cam system", the camshafts being geared together and driven off one camshaft's sprocket (both camshafts' sprockets on the G-Engine are rotated by the timing belt). Some of the less directly visible differences were poorly shaped ports in the earlier versions, a slow burning combustion chamber with heavily shrouded valves, less aggressive camshaft profiles, ports of a small cross sectional area, a very restrictive intake manifold with long runners joined to a small displacement plenum and other changes. Even though the valve angle is closer to what is considered in some racing circles to be ideal for power (approximately 25 degrees), its other design differences and the intake which is tuned for a primary harmonic resonance at low RPM means that it has about 10% less power compared to the 4A-GE engine. This engine design improves fuel efficiency and torque, but compromises power. Power rating varied from 100–105 hp in the US market. Late-model engines are rumored to make slightly greater power but still received a 105 hp rating. Although not as powerful as the 4A-GE, both engines are renowned for the power they produce from such a low displacement relative to other engines. Toyota engineers had skillfully optimized the power and torque from the company's relatively low-displacement engines. 4AGE- Toyota designed the engine for performance; the valve angle was a relatively wide 50 degrees, which at the time was believed to be ideal for high power production. Today, more modern high-revving engines have decreased the valve angle to 20 to 25 degrees, which is now believed to be ideal for high-revving engines with high specific power outputs. The first generation 4A-GE is nicknamed the "bigport" engine because it had intake ports of a very large cross-sectional area. While the port cross-section was suitable for a very highly modified engine at very high engine speeds, it caused a considerable drop in low-end torque due to the decreased air speeds at those rpms. To compensate for the reduced air speed, the first-generation engines included the T-VIS feature, in which dual intake runners are fitted with butterfly valves that opened at approximately 4,200 rpm. The effect is that at lower rpm (when the airspeed would normally be slow) four of the eight runners are closed, which forces the engine to draw in all its air through half the runners in the manifold. This not only raises the airspeed which causes better cylinder filling, but due to the asymmetrical airflow a swirl is created in the combustion chamber, meaning better fuel atomisation. This enabled the torque curve to still be intact at lower engine speeds, allowing for better performance across the entire speed band and a broad, flat torque curve around the crossover point.During rising engine speed, a slight lurch can occur at the crossover point and an experienced driver will be able to detect the shift in performance. Production of the first-generation engine model lasted through 1987. .............................. This revision increased the power to 125 PS (92 kW; 123 hp) at 7200 rpm with a torque of 149 N·m (110 lb·ft) at 4800 rpm (128 hp and 105 lb-ft for US-market cars). If you want to go up against a 4AGE. line up here-

So.. if you had it on carbs would it be a 4AG instead of a 4AC? If the guy on here can fit a 4AGE head onto a 4K, then anything is possible!

I think something electrical like leads would show up in other places, not just a flat spot. You could have a look at night and see if there are any sparks juming around, just whip the bonnet off for a quick drive one night, particularly a damp or wet one. If nothing else was touched then it has to be cam timing related, and if that is correct now it suggests it wasn't correct before and the tuning was covering the fault. You might have to re-tune timing/fuel a bit. Usual causes I can think of would be mixture going lean at that range, or too rich, and the other would be that spark timing is too advanced just there. Pop up a couple of real photos (not bloody phone ones!) of the timing marks lining up and maybe some 4AGE guru can tell you. Check the ignition timing and tell us what it is. Then I'm afraid its a dyno run for air/fuel ratios under load. I'm surprised you don't have a rev counter on a conversion like that.

Ah sorry- fixed piston is a thought experiment.. I know how to do it but I haven't tried it yet. If I'm going up a long hill and I accelerate, it will go from 18 to 1 back to 14.7 to 1 and sit there constantly. Adding more throttle makes no difference as the needle is setting the mixture and its perfect for power at the top end when working hard. I think I'll go read some of Prof Bernoulli's horrible work again (after 40years..) and assume it works on those principles.

Isn't it nice when the brake booster is on the other side!! Great work Hayha!

Yes, it will hold 14.7 until I lift off, which is the way they wanted it to work I expect. Well, driving along watching it I spent a couple of hours wondering how thin the air would have to be before it affected the mixture, velocity notwithstanding. Say 14,000ft in Bolivia would have fewer air molecules passng over the venturi, so maybe it would fill those spaces with petrol and enrich it.. I don't know, but it passed the time! The float bowls don't see the pressure, so in theory it should push the fuel level down the jet slightly IF the higher pressure in the airbox translates to a higher pressure over the venturi. When I've caught up with everything at home I'll go and do some testing with and without the cold air tube connected. The hard thing around the Central West is to find a level road for consistent conditions!

Good God! I never knew anything like that existed! What motor does it run? I was expecting a 4WD wagon with a 4AC...

If anyone has a fuel mixture device fitted, can you post what readings you get in different driving situations. I have it set so- Idle is 1000rpm, 14.7 dropping to 18 or so momentarily then back up then down, never still. It follows the grumpy idle of the cam up and down in both carbs, one with a slightly wider range than the other. It is better with a richer idle than that, but I'm tight with petrol money! Driving away shows “R” for rich for a few minutes until the sensors are well warmed up, then it is under 15 around town unless decelerating with my foot off. The chance of a constant throttle around hilly Orange is pretty slim, so it is constantly loading and unloading, so shows 11 to 1 to 14.7 to 1. That's using around 9L/100km. Cruising at 100kph it shows 18-20, and will stay at that going up a hill with a slight throttle increase of a few mm. Pushing the foot down will bring the mix back to 14.7 and it will stay around there until I lift off and cruise again. I don't know if such a lean mix affects the motor, I was worried about burning valves, but it seems fine. Pulling the choke out pulls the jet down and richens it at any needle position, so I can richen it at 100kph to 14.7 or richer, but it makes no noticeable difference to the power it puts out. That's why it used less than 7L/100km on a trip, over 40mpg. Lifting off and slowing down under a closed throttle goes straight away to 20:1, as lean as it goes, as the floating piston drops right down.. When the speed drops to about 20kph the car gets jerky as the grumpy cam idle affects the slowing down and the car surges. I've wondered if that is an airleak, maybe around the throttle shafts, but I don't know. These are narrow-band sensors & display, so they read accurately around 14-15, then quickly move off to 11 at the rich end and 20 at the lean. The readings are very mobile in use, constantly moving up and down quite quickly so I don't worry about reading the figures, I just keep an eye on the bar graph beside them. Its only on a trip cruise that it settles down for long seconds at a constant mixture, and in the flat lands it will only move within 1.0 ratios over minutes at a time, say 17.5 to 18.5 range. Under power up a hill it will sit constant at 14.7 without varying. I've never seen a wide-band, but would love to know what you actually see when driving if you have one!

I have my setup described in the build topic here- http://www.rollaclub...the-girls-ke70/ Basically twin inch & ¼ SUs on the 4K with a 270deg cam and extractors. As well, I sanded the needles to suit the engine, fitted a cold-air inlet that pressurises the carbs and then a pressure release flap. In the build you can see photos and videos of how the carbs work on the road. The most important mod was fitting a pair of Commodore oxy sensors and a fuel mixture display, showing me the mixture from each carb over the whole range. It woks well enough that you can see the effect of a pothole or a bump in the road as the floating piston bounces up and down, changing the mixture. Sanding the needles was easy, and I just richened the off-idle area by making the needle thinner a few thou. Other odd things that have been done by people is to weight the piston with a few bits of lead shot or to change the shape of the venturi edge and piston front for smoother airflow. However some things still puzzle me- The theory is that the floating piston controls the mixture by keeping a constant air velocity under it and hence letting the needle taper set the mixture at any air flow. But, if the car is running along a flat road and I jam the floating piston in one spot, when I accelerate the increased air velocity over the venturi ramp will richen the mixture. This is just like having the dashpot damper hold the piston down momentarily. The question is, why does it richen when it must suck more fuel AND more air at higher flow? Why does it suck proportionately more fuel than air. While the cold air inlet pressurises the airbox slightly, this is not constant. Under say, 70kph, the difference is nothing, but at 100kph I have greater pressure that atmospheric on the airbox side. So now I have a greater pressure difference over the venturi and it should suck more fuel to compensate for the extra air. But, does it rely on a pressure difference, or does it all rely on air velocity, or does it also rely on the density of the air as well as the velocity?

For something so mechanically simple, the SU carb has a complex system of operation. It seems very straightforward when you look at a cross-section of the carb and have a read over the internet, but I've found that it does not behave in such a simple way. Looking at the diagram, it is made from a body that contains the throttle plate, with a 'top hat' screwed on top of it. That encloses a cup-shaped hollow, floating piston that holds a needle in the fuel jet screwed into the bottom of the body. The little ramp in the body where the jet sits forms a low pressure area behind it and air flow over the venturi ramp sucks the floating piston upwards by forming a vacuum above it. That's what the blue arrows are showing, as air is sucked out vents in the bottom of the floating piston and atmospheric air enters where the red/yellow arrows are, under the rim. The gap between the piston and the top hat is crucial to minimise air leaking upwards but also the keep the piston floating on its air cushion freely. So the theory is, the faster the engine goes, the greater the airflow over the venturi, the greater the vacuum so the higher the piston is sucked up and that allows more airflow. Fuel is added by travelling up the jet and past the needle to be sucked into the airstream by the venturi vacuum. It normally sits within a couple of mm of the top of the jet, so it is sucked out easily. The volume of fuel used is determined by the tapered needle shape and the jet. The jet is just a straight-sided tube but the needle has a taper down its length. At idle the thick part of the needle blocks most of the jet mouth, and as it is lifted by the floating piston the smaller section of the needle allows more fuel up and into the air mix. The needle taper will give you a constant fuel mixture at all revs, or any mixture you want really. You can have a very lean idle that will richen at high revs. The damper in the dashpot slows the rise of the floating piston just as a shock absorber in a strut works. Slow up, but fast down, you can see it rise in one of the video clips then slam down as I lift off the throttle. The rate of rise is governed by the thickness of the oil, and its is there to richen the mixture on sudden throttle openings. When you open the throttle, the airflow increases and more fuel is sucked out. Obviously the piston wants to rise, but the oil only lets it up slowly, giving a sudden enrichment that tapers off as the piston lets more air in and it matches the new fuel volume fed in by the needle. So the mixture goes back to whatever cruising ratio you have the needle set to. This is the SU equivalent of an accelerator pump, and is why it is a demand-fed carb, not a throttle-fed carb like the stock Aisan.. There is a long soft spring down the length of the floating piston core, and this compresses as the piston goes up. You can get several spring rates and they automatically richen the higher rev mixtures by not letting the piston up so far for a certain amount of airflow. It makes needle selection easier as the needles can be thicker in their 'wide throttle' positions instead of being tiny and delicate or in having bigger jet diameters.

Tricky- I thought 'increases front grip' I know that to get more oversteer I have increased the size of the rear sway bay, +/or 'reduced' the front. I cut the flanges off the roll bar upright pins on the LCA so the bar flopped down over them, then put a pair valve spring in there on each side. So the front could roll a bit as the sway bar compressed the valve springs but it got progressively stiffer. You need that roll to get weight onto the outside front wheel to get grip, but at the back you want the outside wheel to slip sideways. In the end all you can do is try all sorts of combinations.

Keep the rear way, thicken it even from a Celica at the wreckers. Take the sway off the front completely with max camber and castor, you want roll on the front to give bite in the dirt, and a stiff rear end so it skates sideways easily. With the locked diff it will want to plough straight ahead as you enter a corner, then the diff will kick the tail sideways once you've got the nose turning. Undesteer in, oversteer out.

Yeah, I've never got into HIDs Raven, I'm too much of a cheapass. I grabbed an ordinary Navra 100/90 for the left-hand headlight when we first got the car because the lights were so bad, but it didn't help. That's when I realised the switching was the problem, so now the left-hand edge is very clear at night. What are the LEDs that they are playing with like? I assume they emit a very clean & narrow range of wavelengths, so they just need to get the power up.

if they're running needles then re-shaping them is easy with some #400 wet 'n dry sandpaper. You can leave the lower stations as they are and just enrich the top end. I think that's the big advantage of needle carbs, while normal fixed-jet carbs are a lot less adjustable. That's why Webers are so popular in race cars, there are quite a few ways to change mixture over the rev range with their 5 different jet setups.

Its a very tall engine too, so you struggle with that as well. I don't think its any longer than any other 2L 4cyl, it sits waaayy back in the Altezza engine bay. I can go and meaure it if you're keen.

One day I had lunch in Lightning Ridge, I hadn't been there for years, from back in the days we hunted opals and gold and sapphires and topaz and rubies and...

You can see the revs fo 100kph with 14" tyres and a 4.3 auto diff, and its running at a mixture of 19 to 1 at that speed. You can also see the temperature of the incoming air!! 30deg with no aircon..

or even more startling, somethng like this!

Few piccies- I saw hour after hour, day after day of enormous Australia, and occasionally something quite startling like this-

So, my mate and his missus have their camper-trailer & a new 4WD to replace the old feral Landcruiser, and they want us to join them on a trip to see Lake Eyre with water in it during September. I don't mind, but I'm not keen to buy a 4WD (probably an old Nissan Kingcab I will re-motor..) for one trip so soon and we're looking at hiring one. The problem is that the usual hire companies operate out of Broken Hill & Adelaide, so we have a long drive paying for every Km at some wallet-bending rate before we get anywhere. Bluntly, I'd take the KE70 as I reckon the reports of how terrible the roads are will be over-rated (not m i n t !) by these city-slickers who don't have a clue about the countryside, but the wife won't let me! So if you know anyone with a 4WD ute that can spare it for two weeks in exchange for some cash, I'd love to know! I know there are quite a few farmers around the Central West with extra utes sitting on the farm, so there must be a few down South. We will Rolla down to South Australia and then use a 4WD for the bit up to Lake Eyre and back. Actually, I'll probably take the Altezza, a bit more comfortable!

A giant gain is made if you cut the stock headlight switch out of the circuit and run relays. The switch then just activates the relays and the power goes battery->bulb->relay->earth. It doubled our light output. How I did it is here, but you might want to buy the $60 headlight relay rather than the little $10 pair I used and make it neater. http://www.rollaclub.com/board/topic/42407-the-girls-ke70/ PS- Fitting a 100W bulb to the left-hand headlight only is a brilliant idea too!

Lol- looks like great fun! Grab the biggest hotdog muffler you can & take the exhaust out through the sill before the diff. That should be good enough if the neighbours are a fair distance away. Welding the diff will help if it stays on gravel, and I assume it no longer goes on tarmac so grab a welding stick. ..and capslock key is just above 'shift'

Not a fan of those black wheels, they always scream "crazed P-plater" to the cops... What did you do about lowering it in the end?? I figure fitting the flares off that silver KE would make it look lower even at stock ride height. I told the girl to use the same excuse if she was ever stopped, 'the modifications are for fuel economy and not power...' and it does keep up with the traffic now!