CI GS

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playtoy

Awesome

DSteck

Single M10, break out the IAT, put the meth nozzle between the MAF and throttle body, and set the gain to about 3 to start. See how it does with the initial and turn on set to their "factory" states. From there, just adjust the parameters to get the AFR in the mid to high 10s throughout. If you have a HPT cable, you can add a couple degrees back in and let the IAT table handle anything that happens if the meth isn't spraying (IAT will just go up).

Pitufina

Awesome! Yes, I have the HPT cable and everything else needed for the meth install. Which table should I use to add the timing? The high octane? So you are saying that the afr can be adjusted using the gain controller and/or the progressive controller? I was thinking that adding an extra pound of boost and a couple degrees may get me where I want to be. I appreciate you took the time to type. I know you are probably real busy at this point.

EDIT: I was reading a little more on the alky controllers and understood what Dave is talking about. The gain controls the pump voltage. So the higher the number on the gain, the faster it pumps/volume (max volume controlled by nozzle size) and possibly making the afr richer. Now Julio also says that changing the turn on point on the progressive controller can lead to a leaner or richer afr. For example coming on sooner=longer ramp up so more meth=richer afr. And Vice Versa coming on later=shorter ramp up(smaller window spraying meth)=leaner afr

Unreal

IAT adder table.

Pitufina

So is it this one spark>advance>iat spark(base?)? It sounded to me that Dave was referring to other table? and let the IAT table remove the timing if the IATs go higher. Thx

schpenxel

Yes

Pitufina

So for example if there any numbers below 100* like -4, change it to -3 or -2? That should add the timing back as long as the base table has lets say 15* and currently let's me run no more than 12* due to the higher IATs? Am I understanding it right?

winters97gt

When are you going to be ready to start tuning down here?

schpenxel

I'd have to see the table and see whether it's a table that adds to or subtracts from timing before I could say for sure. On mine a negative means it's reducing timing, so the cells below 80* on mine are positive numbers. I don't know if that's how they all are or if it's just a weird E40 quirk like so many other things

If yours works the same as mine then your assumption is right. Check out the description for that table and see if it says whether it adds to or subtracts from the current advance

It also is going to multiply the value from that table by a multiplier or two. Mine has a multiplier table for RPM and one for ECT. So if I had +4*, then multiplier of 0.5 and multiplier of 1 then you'd end up with +2*

I'd get the meth on and log it first though. I'd likely not start adding timing until lower than 100

Pitufina

I think I got it. I was looking at someone's tune I found in the HPT forum. I'll take a look at mine as soon as I can read it, but I have a better idea on what I need to work on. I'll be finally done with the school this week, so I'll be home by the weekend. I doubt I'm going to mess with the vette probably until next week. Thanks!

Unreal

You got it. If it is zero, then it doesn't do anything. If it is -4 at 100F then it pulls 4 degrees at that. With meth you can bump the thresh hold up a little. Maybe have it pull -2 at 100F. Just don't mess with the high values too much. So if meth doesn't work, still hits 130+ and pulls a good amount of timing.

Pitufina

Great! From what I gathered most see temps in the 60-80s when the meth is activated. So yeah, I'm not going to change anything over 100*. Thank you!

DSteck

End of July perhaps.

playtoy

Where are you going to be located? If your going to be close to houston I'll volunteer to be your first texas customer. I'm just now getting around to putting my car back together after a year of being torn apart in the garage.

Pitufina

I believe he told me Austin area.

Unreal

Austin is close to Houston I use to drive from Austin to Houston for IDRC races in college.

Streetk14

Seems like you've got the basic idea. If you're going to run a smaller nozzle and not adjust the amount of fuel the injectors are providing, then I'd just keep the higher end of the IAT/spark table as it is. If the meth fails, it will just reduce timing as it does now. I'd probably add a few degrees below ~85 or so in the higher airflow ranges.

Pitufina

I'll definitely keep that in mind. I won't add the timing until I see where is at after adding 1psi. If it's still too rich like low in the 10s then I'll add 1* at a time to see where it goes. Thank you.

Streetk14

If you don't want to be "meth dependent", then I'd be careful about adding more boost. If you want to do that, I'd plan on going through the tune more thoroughly. For a beginner, what I suggested is very safe and almost fool-proof.

You could set it up ECS style and have it pull all the timing when IATs get over 100 or so. That's what Doug does to prevent his builds from going BOOM if the meth fails. It isn't perfect, but it can work and save your engine. I myself never found a way to balance it perfectly. If I set it too low, I'd get a nasty bog before the IATs would drop from the meth spray during street driving in warmer weather. Also happened after sitting in the staging lanes at the last 1/2 mile event I ran that car at. I ended up raising the timing pull to a higher temp, but then you're faced with a more likely possibility of engine damage -- as on a cooler day with good airflow over the intercooler you can see lower IATs even without the meth spraying. At least through a few gears. It's not perfect.

Then there's also the fact that you may need some tweaks to the MAF table or some other airflow tables if you're messing with engine airflow. It's usually not as simple as just adding boost.

Personally, I'd do what Dave and I recommended. Nozzle and adjust meth system for mid-high 10's across the board. Add some timing to the IAT spark table in a point where you'd only reach with active meth flow. Believe me, it's going to make a lot more power than it does now at someplace like the strip. Not only will you get the full timing Dave intended in your original tune, but you'll be getting some extra power in a very safe way. If the meth fails, it won't matter one bit.

My 2 cents anyway.