Question for stock turbo'd AEM meth users

raasfaas · May 15, 2009, 07:11 AM

I had posted this in the regular WAI section but I may get some responses here too: I'm trying to get an idea of what you guys have your start/full spray psi set at on your kits. Reason I ask is because AEM recommends setting the start to approx 25% of your maximum boost and setting the full spray to maximum boost. I'm spiking to a max of 29psi which would make my start at 7.5psi, but according to the meth gurus spraying meth too early can cause knock so I've set mine to 10psi. Its the full spray that I need to know about. If I set my full spray to 29psi (which is the max i'm running) then my meth will only be at full spray for that short period of peak load because the stock turbo can't support more than approx 22psi up top so now i'm progressively working backward. So I set my full spray to 21psi to keep it going up top.
The problem now is I have an overly rich spot in my logs, which I would assume its from when the meth goes from start to full in such a quick instance. My fuel tables look nice and smooth, but now I have to make a pretty big transition to try and lean out that spot (right around 4000rpm 310 load)
What do you guys have your settings at and do you notice this also?

Post #11 shows one of my logs with the rich spot:
Need advice on tuning meth

redline7 · May 15, 2009, 07:45 AM

I have my reservoir in the trunk and the car builds boost so fast that to be honest I have mine at about 6-7ish since in the split second it takes the pump to engage and build pressure to spray, I'm probably at 10 anyway. However I am only boosting to 19psi so you might be fine at 10. I think tho that since your boost is pretty high, you might be better having it come on full at 22psi or something. I played with mine for a while before I found the sweet spot. Just be careful the little switch is a bit easy to push inside the unit. Had to open mine more than once.

raasfaas · May 15, 2009, 11:10 AM

Yea same here, the time it takes to go from 10psi to 21psi is so fast that I'm sure the meth doesn't even have time to progressively build and it just pretty much comes on full spray instantly...which I think is where my rich spot is stemming from.
I'm going to try and set the full spray to something a little higher, but that would mean that at redline i'm no longer at full spray and I would have to retune my afr and timing back down...which kinda defeats the purpose. I'm sure I can tune out that rich spot but it would mean I have to add at least a full point in that load area which may lead to some inconsistencies in normal driving conditions

Evoryder · May 19, 2009, 04:58 PM

I have my meth start @ 10psi...you have to play with the tuning.

raasfaas · May 20, 2009, 12:08 AM

Quote:

Originally Posted by Evoryder

I have my meth start @ 10psi...you have to play with the tuning.

Evoryder on your kit, what psi do you have your full spray set at? I was reading the post you made in my other thread, and I see that you're holding approx 23-24psi at redline, do you set your full spray to your max boost (29psi) or where you taper to (24psi)?

Evoryder · May 20, 2009, 11:32 AM

My setup is for 10psi on...anything below off. No taper, non progressive. Just on and off.