the initial logs are much longer, this one is about 4 1/2 minutes. This is the engine I have featured here:
Rebuild 1600 fitted into GTJ
As the lower range performed quite drive able, I went for WOT first. This is only the fifth combination of jets!
The headers used where not working when installed on a 2 liter engine, so I first went for WOT settings, to see whether the combination of components was a total miss or could be used. As you can see, it pulls in a straight line up to 6700, so basically this will be quite a neat engine if perfectly tuned.
What you see from this run: The WOT over 6000 rpm leand out too much, so no need to push the engine that high.
There is one rule most hobby tuner donīt follow: Only change one carburetor part at a time. Even as you may be absolutely sure another idle jet was necessary and the high rpm range needed a smaller air jet as well, if you do both you will loose control of your changes. So this run was only made with a 160 air jet instead of a 180. Anything else was was left as in the log before.
Now all I do is to take a previous log with same throttle, gear, rpm combination and put it as overlay on the new one. You see exactly the changes this single jet did.
So my typical tuning session for WOT looks like this: Engine started and driven to a free stretch of road (engine is already warm!). Deceleration to 3rd gear /2000 rpm, full throttle up to the necessary rpm important for the change, maybe shifting to 4th gear to see transition and drive to a save stop. Next correction, same procedure, next session.
If I go for part throttle settings, I use another gear and floor the throttle for maybe 20° opening, just so much the car accelerates very slowly in this gear. This gives a long black line, slowly rising and the exact change in AFR can be seen. This way you can perfectly see the reaction for a different idle jet or main jet. Slow changes of the throttle are necessary, because at fast moves of the right foot the acceleration pump starts injecting and causes incorrect AFR readings. I usualy put my foot in a position that remains stable even on street bumps or even use the hand throttle (very dangerous!) on empty roads.
The point is you, if you only change one jet, there is only a limited region where it affects fueling. You put this into one drive, then do the next jet, next test.
Only at the very start (when huge changes in jets may be indicated, because you where completely wrong) and at the end of tuning, when all is OK, you do a complete log, using multiple load/ rpm/ and gear conditions.
If this is as perfect as you can do, you go for transitions, where you try to provoke hesitations and find acceleration holes.
This is still a very carefully tuned 1600cc, so a near stock behavior should be the aim.
(Of course, you can not expect a 1300cc engine with a 308° race cam, 45 Weber, 40 mm main ventury and a 6 foot exhaust system to take sudden full throttle at 900 rpm and start to strongly accelerate, even in 5th gear. You have to see the technical limitations of a basic set up.)
This engine takes full throttle from 2000 rpm and runs through different regions of behavior. If driven in a civilized manner, given not more than 45° throttle, it makes the car feel as if it had lost a third of its weight, because it pushes it around so easily. That is where you realize how much fun a well tuned engine makes, even driven in traffic. Up to 3000 it is very tame, then pulls as usual until 5000 and then suddenly starts to show itīs special parts by rocketing over 7500 with ease. So if you do a really hard start, you have a surprisingly quick car.
The 4 in 1 header seemes to have pushed the maximum power range much higher in rpm, but it is no race engine at all as some predict with such an exhaust.
The same cam on other engines did show quite less sympathy for high rpm, but as this engine has been optimized for flow in any aspect, this is not really a big surprise.
Because of bad whether I could not work on it for the last weeks, but I will post a long log you can load into tuner pro and watch your self if I`m done.