nismorx7

Hi guys,

I just finished a quick street tune on my TII at 10psi. I created the timing map by looking at several maps I found on here and by reading a few articles.

What I was hoping for is for some advise on the IGL map.

I think its too conservative and the car feels slower to spool up than it should. I'm wondering how much timing I can add and where. Looking for advise more in the spool up and drive-ability ranges.

Running 15 split everywhere.

Car runs great otherwise. Pulls smooth.

Mod list:
s5 TII motor
Mild street port - idles smooth
T04S04 (60mm wheel)
front mount int
550/1680cc
50mm wastegate
stock spark plugs (7's and 9's)
stock ignition

nismorx7

And I yes, I incorrectly spelled advice twice.....terrible

arghx

iTrader: (3)

what octane fuel do you have?

Give more specs on the turbo please. Is this a bolt on hybrid? If not, what kind of manifold do and turbine housing do you have for it?

nismorx7

Turbonetics T04S04 T-58, .70 A/R compressor, .96 turbine. 58mm wheel, non-ball bearing (similiar to a 60-1).

T4 turbo flange is non divided on turbo, bolted to a divided manifold flange and tubular steel manifold.

91 octane fuel

Thanks for the interest arghx. Hoping for some feedback. I can post up the .dat file as well if needed.

I know my set up isn't the most efficient for spool up (divided with non-divided, older turbo etc), but I am totally out to lunch on what kind of timing numbers I should be running during spool up and general cruise situations.

The IGL map I created is a shot in the dark in my opinion. Any feedback is appreciated.

arghx

iTrader: (3)

Based on that, there a few comments I want to make.

The timing you are running in mid to higher loads, say PIM 15000 and up (half a bar boost or so), is definitely less than what you can run given that turbo, even with your 91 octane.

I am speaking only based on previous experience and rule of thumb, but what you could do is basically clear off your last two rows' values. Shift everything from PIM 9000 rows up to PIM 20000 rows down. Then evenly interpolate. That big jump in timing you have from PIM 8000 to 9000 could be ramped in with the additional two rows. Final result would be what you have in PIM 20000 today being in the 24000 row, and entirely new timing values in the 10000 and 11000 rows.

The best way to adjust timing is on a dyno. The closer you are to optimal, the less power you will incrementally pick up as you advance timing. If you are way off, timing helps more than when you are close. And you still need safety margin.

By advancing timing in the medium load areas, you are improving torque by firing the leading plug earlier. However, that typically lowers exhaust temperatures, which gives less energy to the turbo. Turbos are weird that way... sometimes you make more torque at low rpm with less timing, when you have limited turbine energy available.

Do this for me. Lug the engine at 1000rpm in 5th gear (yes, 5th). Accelerate up to 4000rpm if you can do so safely (or 3500 at least) while taking a data log. Since the engine speed is ramping so slow, it eliminates the transient aspect of spool -- the bearing design and inertia of the wheel are nullified, and it is merely a matter of turbine energy, turbine housing design, and boost control.

The boost curve you see here is essentially the most boost you can get right now with your hardware. If you advance the timing like you are proposing, this boost curve might actually get worse due to cooler exhaust temperatures--but maybe the torque improvement from advancing the combustion will outweigh the loss of turbine energy and what I expect to be at least slightly lower boost.

Timing can only do so much for you. Maybe if you advance the timing it will be good enough for you (in terms of your personal appreciation of the spool), but there are limits with that turbine housing, and it sounds like you already know that. The turbine housing and the turbine energy available determine that max boost curve (5th gear lugging), and the bearing design and wheel inertia can only affect how quickly you can achieve that torque line while you are waiting for the wheels to spin up.

If I am doing a lugging test and I get 5psi at 2500rpm, going with ball bearing or identical but lighter compressor wheel won't make that be 8psi. Adding timing usually doesn't help that either, due to lower exhaust temperatures. Only changes in the turbine energy and turbine housing (and maybe manifold design) will affect that.

It's easier to separate out the difference between these factors (lugging boost curve vs transient effects of wheel and bearing) when you have a loading dyno and can lock engine speed.

nismorx7

Awesome, thank you very much arghx.

When I have some free time in the next week or so I will remap and post another screen shot, so that you can verify that I understood what you meant.

I will also try the 5th gear lugging pull you mention and use it as a "control" to see how my 3rd gear pulls, for example, compare.

Thank you again for the advice.

j9fd3s

iTrader: (3)

i might try the lugging test in 3 conditions, one as you have it, one with 2-3 degrees LESS timings, and then one with 2-3 degrees MORE timings.

hopefully you can lay the rpm and or boost traces on top of each other in the datalog, and then it should be easy to see which one is better and where.

if there are sections where the curves are on top of each other, pick the one with the least timings.

simple!

you also may want to start this at the lowest boost you can run, and ramp up.

you might also try it at like 50% throttle and see what it does.