Thread: Timing opinions for rebuild

Nooo don't use Rom Editor, it's sooooo lacking compared to the TunerPro, which is free!

I would stick to the first timing map, it's friendlier for higher boost. Also your TP values will need less rescaling.

I'll explain TP scales in the next post.

Also about the timing in the vacuum. Ethalpy's tune is great, but if you look at my tune you can see I'm running more timing in some particular areas. I compared the Calum map that I have to the base timing and then started increasing timing. You want to make sure you blend the surrounding cells. It's kinda like Photoshopping in a person into a picture, you want to blur the corners so that it blends with the rest of the map.

Blending timing is a good way to continue a smooth powerband. As much as I love being the feeling of the car pushing me to the seat as soon as I hit boost, the car parts (transmission, axles, etc.) like smooth power delivery, which also helps your traction. The instant torque dump is what kills the transmissions and your traction.

My T25 BB, had 0 boost lag, it dumped a lot of torque as soon as you pressed on the gas. This made me spin the tires from 4k-redline. Now with a journaled T28, and the same setup I was making more WHP, but the tires would hold traction down.

Thanks Vadim. Strange enough, I didn't even notice that you just updated those maps on that thread yesterday, neat. I also never saw your modified one below it until now. Looks pretty nice. I'll definitely rock that one for the off-boost portion of the map.

About TP Scales
TP Scales are honestly irrelevant when your looking at a completely different tune. Basically TP heavily depends on the K value. Unless you know another tune's K value, Injectors and MAF, TP scales are fairly useless. This is why I added boost figures above the two maps I pasted.

Stock K value is 298, well the maximum TP on the stock car is 75-80 TP. If you were to simply add boost without changing the injectors or MAF, at 10 psi your Max TP would be over 100.

When you add a larger MAF, your K value would have to go up. For example K value of 400, thus your Max TP for the same 10 psi is now going to be say 150 TP.

Now when you add larger Injectors, your K value has to go down. Since K value basically controls the injector pulsewidths, along with bunch of other crap hence TunerCode suggests you don't modify it too much. With bigger injectors you flow in more fuel in similar mount of time (minus larger injectors open/close slower). Thus you reduce the K value back down to 300. Your back somewhat on part with your TP that was with boost and stock injectors and MAF.

Now in my case, my injectors are 550cc and MAF is E60 (~320whp max). The injectors are way larger then the MAF power rating wise. Thus my K value is actually down to 210. Which makes my TP scales be back down to the sock 75-80 Max TP.


Finding out TP Scales
This is a tricky one to do, even with the proper equipment. Just like with Timing you want the TP scales to be easy flowing and blended. It's not a good idea to have the last two columns be "50, 100" and expect to have a nice powerband. Actually you probably would have it lean out a good bit too.

To properly scale the maps, a boost gauge and Map Tracing is a must. While a wideband is optional, but is heavily suggested.

Next it's important to know how Nissan reads the rows and columns. I personally thought if the row said 2,000 RPM and I was going 2,225 RPM then it would be in the lower one. That's not exactly the case though. The ECU will usually read up, so technically I would be in the 2,400RPM scale.

If your scales are very far apart the ECU will calculate an in between value, which may not always be the most optional solution. In the 50, 100 TP case, when you are going 60 TP, it will look at 50 TP + a little timing. At 80 or so TP it will start using the 100TP's values. So the ECU knows how to take care of itself when you neglect to give it information, but you loose resolution. This specifically starts kicking you when you want specific timing/fuel amounts under specific boost.

Back to Tuning the Scales
The problem with using TP scales is, you can't tell if you are in vacuum or boost. Thus you have to manually add PSI's per column if you ever share the tune.

Vacuum TP Scales
Vacuum scales can stay the same for the most part, except for the parts that lead up to the boost part of the TP scale. Like I mentioned above, you want to avoid big jumps in TP scales.

Boost TP Scales
Now to start getting dirty and finding out the Boost side of the TP scales. You may want to let someone drive the car while you stare helplessly at the boost gauge and the Map Trace.

Have the car at 0 PSI and see which column you are in. Look at the actually TP number too. While you may be at 55TP you may be in the 70 TP column. Thus you want to reduce your 0 psi column to be around 60 TP. Next get to 5 psi check what the TP is and what column that you are in and adjust accordingly.

I personally have 3 columns for in boost TP. This gives me fine tuning room since I'm only running 7 psi. If I run more, I have plenty of room to increase the TP to account for it, and not have to worry about touching the 0 psi column.

Once you get a good comfortable TP scale jotted down, update the Tune. I have same TP scales for Fuel and Timing. Stock tune doesn't. I rather keep the TP scales together that way I know that if I'm in one cell in a Timing Map trace, I will be in the same cell in the fuel map.

Make sure to update the timing accordingly too. It's a good idea to tune TP scales with a very safe base map, otherwise you might knock if you give too much timing to a certain in boost column.

Ha yeah I've been busy with fine tuning my ecu and trying to squeeze me gas mileage out of it. Before that the other maps where not too relevant for most cases .

Awesome, thanks for the help Vadim! Until I get the car running and tuned 100%, think it would be safe to leave the TP where it all is, and tune what I believe is going to be the off-boost area (say tune for that up to 48 which is the closest I currently have to wear your 0psi starts). Then once I get driving, find the diff TP's in different psi levels?

The GTi-R timing map is for 8.3:1 CR and 100 octane japanese fuel on 8 psi stock T28 boost...

GTi-Rs came with 12lbs of boost stock from what I recall. I believe it was a normal 7-8lb WG spring, but had a boost-control solenoid which made it 12lbs. I also never knew Japanese gasoline was 100 octane. Lucky... best I can get here is 93 or 94.

I too was wondering if the high-octane tune wasn't for something like 95-100 octane. Makes sense to me.

As for stock boost on a GTi-R, it is 10.6 psi (about 173 kPa). That is also what the wastegate is set for. There is no boost control solenoid.
Maybe I'll spend the time and find the source of that info again.

IIRC, Japan is using the same octane rating method as in Europe - RON. So if the tune was for 98 octane RON you should drive it with 93 octane AKI ( (RON+MON)2 ).

p.s. The open chamber on the GTi-R head (no quench) lowers the CR to 8.3:1 which means you can dial in more timing , but the lack of quench lowers the speed of flame propagation too - thus even more timing to be added (this is the main reason for the higher timing).

Then wherever I read that was misinformed, I know I read that somewhere. Oh well.