ninerwfo

Hi-ho all,
I’m after a bit of sage advice on how to best progress the tune of my Australian NB8B track car. You could describe it as basically a “tribute” build to Andrew’s “Acamas”, or as an S1 build, without the aero. The main difference is the GenII GTX turbo (sorry), but apart from that, it is pretty much a standard S1 engine build, usage is 1% road, 99% (basically it is only registered so I can test stuff without signing up for a track day).


The new engine has been dynoed for wide open throttle a couple of months ago, and since then I have worked on acquiring some MS3 & TunerStudio skills, so that now it is starting and idling quite nicely. The car has racked up about 500kms (300 miles) since then, and it drives great, the logs show AFRs are very stable, if perhaps a tiny bit rich. It dynoed 404hp. Sorry the graph does not show torque – it was the end of a long hard day and I just plumb forgot to ask for a torque reading.


This is where I hope the collective wisdom might come to the rescue - I am now at the next stage of refining the tune, have been watching Andy Whittle’s YouTube videos, and feel like it is time to make a start on using VE Analyse Live!, and/or do some hand tuning using the calculated tables function. But I am still very much a newb, and am pertified of undoing or wrecking the good work that was done on the dyno and damaging an expensive engine.

I am planning to schedule another “wrap-up” dyno session in 2-3 month’s time to double-check and “tickle” things a bit (have swapped out the LS coils for the Haltch IGN-1As, and changed mufflers), but I feel like I would get more value out of that if I could progress the road tuning a bit.

So I have been going through Tuner Studio menu by menu to familiarise myself with the tune, and I have a few questions about some things that don’t seem right to me. I guess I'm trying to figure out whether:
(i) these things have been done deliberately by the tuner for specific reasons that I am not understanding, or
(ii) these things have been overlooked, and should be corrected.

List of "things" that seem incongruous in the tune:

1. Engine and Sequential Settings > Injector Size = 1300. But they are ID1050x injectors, with an actual size of 1065cc - why is it scaled to 1300, and what is this trying to do? During the build, I remember asking the builder did I need 1200cc injectors, and he said that it was possible to make the 1050x injectors act like bigger ones - is that what is going on here?

2. Fuel Pump & Pressure Control > Static/Target Rail Differential Pressure psi = 43.5, but the actual fuel pressure as measured by the FPR gauge in the engine bay is set to 65psi. What to do here? (Am in the process of organising a fuel pressure input to MS3ProPnP, have used up the other 2 analog inputs with oil temp and pressure. Only 2 extra analog inputs - seriously?)

3. Injector deadtime is set to 1.085ms. But the Injector Dynamics spreadsheet @ 43.5psi base fuel pressure gives a deadtime of 0.995ms. Should this be changed if the Static Fuel pressure is changed to 60psi?

4. Deadtime voltage curves are not the same as Injector Dynamics specs

5. Injector small pulsewidths are different from the Injector Dynamics specs

6. Non-linear small pulsewidths are set for 40psi – again, should these be set for 60?

7. Ignition Options > Ignition Input Capture = Falling Edge. But MS3Pro manual says it should be RISING EDGE (see p. 88)). Should this be changed, and will it affect anything else?

8. Is it okay if the AFR goes lean on throttle lift-off?

Please understand, I am not necessarily seeking specific tuning answers here, just some advice on how you think I should approach this next stage. I know that if you can answer these questions you possess specialised, valuable knowledge, and am happy to renumerate accordingly and organise remote tuning consultation if that is what is needed. I live out in the bush in Australia, so this sort of expertise is thin on the ground.

I also know that one obvious answer would be "just ask your dyno tuner about these things" - but that is harder than it sounds. He is constantly travelling with racing teams, and while he does great work on the dyno day, he is very hard to get hold of, and not that interested in spending time chatting about progress or strategies - he is more of a "just bring it in and I will fix it on the dyno" sort of dude. I was a bit lucky to get him to dyno the car, they usually do not touch anything except Haltech and MoTec, but because they built my engine in-house, he was happy to work with Megasquirt and TunerStudio.
So over to the brains trust – should these list of things be “fixed” before I start Autotuning, or am I just being paranoid?

Many thanks

Log of some 3rd gear road pulls

gooflophaze

In tuning there are 2 things to keep in mind: There's the mathmatical model of X fuel at Y airflow = correct AFR. But if the mathmatical model was 100% accurate, we wouldn't need to tune. Granted, the better your data and characteristics you put into the model, for the most part - the better your initial outcome is. But once you start road tuning, you mess up the model - so it becomes a wash. The values you're concerned about aren't really that large if the map is good. That should answer 2-6.

1. Part of the model - injector size and displacement sets up your reqfuel. You can change your reqfuel by itself (useful for just getting a car running), it has very little bearing outside of initial setup.
7. If it works, don't **** with it.
8. That's called fuel overrun - saves fuel, cools the EGT's pretty quickly.

18psi

iTrader: (76)

I saw your email, still haven't had time to sit down and go over it, sorry.
So pardon if my replies are off, since I haven't reviewed your post-dyno tune:

1) because you're running 65psi base pressure
2) nothing
3) see #1
4-6) open the ID1300 spreadsheet, set your pressure, and hten re-check all hte injector settings.
7) if your car runs good with this setting, I wouldn't touch it.
8) yes. expected even

the next stage is me going through everything and sorting it, which is what we discussed, but I've been lagging like crazy for reasons you already know.
but I still plan to do it. lol

Ted75zcar

iTrader: (2)

Doesn't the ID1050X datasheet have data for 65psi?

18psi

iTrader: (76)

ninerwfo

Awesome sauce! Thanks all and special thanks to Vlad. I can now sleep soundly - will sit tight till you are able to do your thing!