I'm just putting out a little call for assistance!

I've been working on this S13/VH45-TT swap (more or less solo) for the past few years as a learning project. It finally drives this year! I've got Nistune all hooked up and in my laptop and I have a very rough tune just based on the old threads I've read by 'qsiguy' about 10 years ago, but I'm looking for someone or some people to guide me on my Nistune adventure. Keeping in mind that this is my learning project and failure is a possibility, I accept this and would still like to learn enough about tuning to get it going even if it wont produce the same power that a tuner and dyno would get. After I'm satisfied with what I've done and have learned about all I can, I'll take it to a pro. It has 2 GT28 turbos, 38mm tial wastegates, and is set to the lowest spring (I think around 4.5 psi). It seems to run pretty good right now but there's some (big) rough spots in the tune.

Any takers? I can post logs, maps, ect.

Thanks!

Yeah post up the fuel and timing maps.

If you've got the cranking/starting squared away, and the thing is actually running, that's a huge step.
Do you have a wideband O2 sensor?

Sorry to somewhat necro my own post and take forever to reply... but I ran into some issues last summer and got sidetracked with buying a new house and moving the project into the garage. To answer that last post though, yes I do have a wideband that I have set up to log in Nistune.

I'm buttoning up some new wiring work and coolant line revisions this week and I'll be ready to break out the laptop for more DIY tuning in the coming days/weeks.

So again, if anyone feels like helping me out on the side sort out tuning problems... it'd be great!

Okay, so I got the new electrical and cooling tweaks done last night and turned it on so I could pull the maps, in case anyone wants to take a look and give some feedback. Right now it's entirely not optimized, I just tried to make it safe enough to have somewhere to work from. Feedback is more than welcome!

Fuel Map:



Timing Map:



Timing Scaling:



Fuel Scaling:

The first thing I see is that it looks like your fuel values are setup to just be raw, with no O2 sensor feedback. I think the values are supposed to be over 120 or something in order to have O2 sensor feedback... so you might not run too great just based on that. Are you able to monitor your wideband readings while you drive? If so, what air fuel ratios do you see throughout the range?
It also looks like your fuel is set to 0 for idle, which also seems odd. I wouldn't think you'd be getting any fuel at that point.
You mentioned there's some rough spots in the tune... does that mean the car is bucking or doing funky stuff as you drive it, or what?

Thanks for the reply! I may have my fuel table understanding backwards then? I was led to believe that if I set it to 0 then it would just adjust based on the O2 and I wasn't at all aware of the 120+ values being special so that's something I can look into! I do have the ability to log my wideband while I drive along with everything else except boost unfortunately... As far as my idle AFR goes, it's usually between 16-17 at the current setting.

So right now the main rough spot is anywhere below 4k rpms and more than 25% throttle or so. I'll be driving down my long straight road around 2500 or 3000 rpms, and at that point anything more than about 25% throttle will start sputtering and almost wont even accelerate at all. If you get it up to 4k rpms just accelerating slowly, it acts normal all the way there, and WOT around 4k rpms it seems to hit boost, wastegates start actuating, and it almost feels like what I'd expect it to. AFR around this point is usually around 11 at peak boost if I remember correctly, I can check my saved logs though and be sure.

I probably have some logs saved on my laptop that I can take some screenshots of when I get home. I plan on doing some logging over either this weekend or next, I just have to renew my registration because it expired last month.

Yikes, I'd almost want real time feedback as you're doing this as opposed to logging.
When you're first setting everything up, you want to make sure that its not choking and such due to being too lean, as that can cause damage. So if you drive around and do a few logs, you could be causing damage while you're trying to fix it.
Of course, it could go the other way too... you could just be running WAY too rich before you get into boost. Have you pulled any of your plugs and see if they are black? Can you smell your oil and see if it smells like gas?
I'll see if I can get a shot of my fuel map when I get home, but I don't think its anywhere near as linear as yours... I think it's mostly flat (or with very little slope) until you really get into the higher loads, at which point it ramps up like a mofo haha.

I got home late and then 50% had a bunch of other stuff to do, and then 50% just plain forgot to get a shot of my map. Sorry!

Okay thanks for the info, yeah it's pretty rich before boost so I can work on that. I'm having a problem right now with my electric fan relay not switching so I can't do much without fixing that problem first which I will work on this weekend. Speaking of problems, the way the exhaust manifold is, I can't pull the plugs without pulling the engine and removing the manifolds. I read some more of the Nistune documentation and through some other forum posts and I think I'm going to start from scratch on the tune because I completely missed a step in the very beginning, which is changing the K-constant and getting the fuel trims as close to 0% as I can. I'll get my fans working, reflash to stock, do the K-constant, fuel trims, and see where that puts me I guess? My intention is to get another motor sometime early this year to do just a mild build on and use the motor I have right now to learn how to tune and get all the basic fabrication and wiring nailed down... my sacrificial lamb engine.

No worries about not getting the map, plenty of time!

Holy crap pulling the engine to change the plugs is NOT ideal haha.

Here's my fuel map. Its a bit odd in that I don't really increase the duty cycle as RPM increases, but this is what nets me the best AFRs under boost. Cruising is pretty good too.


Obviously there's some cells that you'll just never get in to, so those aren't tuned.

Awesome, thanks for that! It's always good to see some other maps that are working to give me a little better idea. Yeah the exhaust manifolds make life difficult, I'm hoping that once I get the front end tubed there will be more room to work with. I think I got my main coolant issue fixed this weekend, where it would suck up air as it cooled. I think it was just a ton of tiny leaks that I patched up, you know like where a hose goes on a barb fitting or where 2 metal fitting screw together. I also got the new electric fans working, yay for me. The power steering is squealing like nobody's business though and that's super annoying but I'll just have to deal with it until I can replace the pump.

Right now I'm working on resetting the timing because I might have done it a little off last year. So, being unsure, I'll just find a timing light and double check. When I set it last year I didn't use Nistune to lock the timing at 15 degrees then set the engine to 15, I just did it while it was idling and I guess it can move around quite a bit on its own if I don't set it. Plus I pulled timing manually and I'm kind of thinking I should set it to stock timing and use only Nistune to pull the timing?

Thanks again for the help! Lots of learning going on here but that's why I started this whole project.

Yup, you should set it to stock timing and then use Nistune to pull it.
To be honest, I've been looking around to try to see where I can lock the timing via Nistune in order to catch it with a timing light. Do you know where that button is?

Yeah, I just had to look it up again but I found it. It's in the Nistune Software Useres Manual on page 60 under "Active Testing" just in case you want some more info. But, from what I understand, you can use this to lock the timing at whatever you want for testing purposes as well as do some other things if the board supports it.

Small update? Sorry for the quiet time, winter quarter homework is kicking my butt and it's been raining nonstop so I haven't been able to take the car outside.

I decided to take it around the block today and see how it did. I modified the fuel and timing tables, the results were less than ideal but it did give me a good idea of how the changes I made affected things so it should be much better next time. It looks like I basically started getting it too rich way too fast and it's probably got too much timing pulled. A new problem arose today though, the damn coolant started getting too hot for some reason. It worked fine a few months ago, the only difference is that I put a fan shroud and beefier fans on it. So, not sure what the heck that's all about. I probably drove about a mile or a mile and a half and in that time the temp went from 85c to 101c when I parked it in my garage.

Here's some random information, I did a trace of the timing and AFR during the drive so here's the pictures of those:




I also took a semi-random screenshot of my log during part of the drive. AFR, timing, load, it's all there.

Which one of those traces is AFR and which is timing? I'm guessing the top is AFR and the bottom is timing just based on the values.
AFR isn't TOO far off. Does your sensor bottom out at 10:1?
Pull a little fuel, add a little timing. Baby steps. Timing can affect your AFR's as well, just based on volumentric efficiency, heat, scavenging, etc.
That bottom graph is cool and all, but without the axis labeled and numbered, its kinda useless.

Also, 101C isn't TOO bad. Do you have the fans rigged to a manual switch, or are you using NISTUNE to control it? Should be able to set what temp they kick on at. Did you get any air in your coolant system that you need to bleed out?

Good progress. You're on the right track! Keep it up!

Yes indeed, timing is on the bottom graph. I have the fans on a manual switch. I idled it until it hit around 80c or so and turned the fans on then prepared for the drive after that. Timing seems kind of hard to adjust isn't it? Fuel is pretty cut and dry, add or subtract to correct the AFR. But what's the best way to do the timing? Just slowly increase until it detects knock then pull it back?

The temp just worried me because it was climbing so steadily and the ambient temperature was probably only 45F, I drove it in the summer time about 20 minutes to my new house without a fan shroud and it barely hit 95c... really got me scratching my head. I went from eBay fans with no shroud, to the ISR fans and shroud. I just went to check the coolant for air since it's had a few hours to cool off. No air and no leaks, so that's good news.

Also, I figured out my squealing problem. I had the belt way too tight and it was putting too much tension on the power steering pulley. I loosened it quite a bit and the squealing is much less noticeable, I probably fried the bearings or something having it so tight so I doubt it will ever be silent. Probably have to just replace the pump later.

I appreciate your input, it's nice having someone to bounce ideas off of and try and get me going in the right direction at least.

Yeah timing can be a pain if you’re starting from scratch. Typically vehicles that have similar bore and stroke (as well as materials for the head and block) will end up having similar timing values.
Otherwise yeah, kinda have to dial it in slowly either until you see a little knock, or you’re happy with the power and results.
Just keep in mind not all fuels from all stations are the same, weather and engine cooling conditions change, etc.
Timing can be dangerous.