I know this is a tuning question, but considering the FI and meth part of it, I thought I might get better expertise here.

When my car was tuned last with the meth injection, it was tuned on the safe side of things. I have a Snow Performance meth injection kit and was using a 50/50 water meth mix. The meth was setup to start spraying at 4#'s of boost and at 10#'s of boost was to achieve max spray. Now, with my wideband 02's at WOT it would usually sit about 11.5 until the meth came on, then it would dip down into the 10.6-10.8 range. Now I believe Bryan Herter to be one of the best tuners available. Especially considering that I am running my setup all on the stock 95 PCM, however it seems a little rich IMO to be running at mid to high 10's in the AFR. Ideally, I would think I would want 11.5.

Yesterday my car went on the dyno, and while on the dyno the guy shut it down a few times as he noticed my AFR was bouncing between 11.5 and 12. I assessed things and noticed that my methanal injection was not coming on. We did a few more pulls that remained in the 11.5-11.8 range AFR wise, but still no meth.

I'll be checking the meth injection setup later this week when I have more time, but my question is; wouldn't ideally the car make most safe power at 11.5 AFR? I am guessing that potential power is lost when the meth is coming on and its at 10.6 (sometimes as rich as 10.4). Now, I also know that the meth has cooling cababilities as well, so without the meth I am sure my IAT's are hotter, and am closer to detonation.

Ultimatly I am asking, should I be seeking a true 11.5 AFR with the meth spraying? Or am I better off just getting the meth working again, and running with AFR's of 10.6-10.8 at WOT?

 

If it was me, I'd probably leave it the way it is, you have already had a problem with meth not coming on. If you lean it out and the meth fails to come on at a WOT 1-4 pull with the excess heat and lack of meth, you might be picking up pieces of your pistons out of the oil pan. But if you were to lean it out, I'd keep it around 11.3 or 11.0 just incase. See if it makes more power like that, if it doesnt, put it back.

 

11.5 tuned with meth spraying will yeild more power, but like Ricci said, you already had a problem once... just be careful.

 

Well, that is the whole reason for having a wideband, and a light saying when the meth is spraying. We knew the meth wasn't spraying, but since it wasn't going lean we stayed in it. Obviously if it were lean any time then we would have gotten out of it.

Failsafe's are what save the motor. Granted my motor being forged and built very strong can take more abuse than a more cheeper built one with non forged internals, but want to keep things safe ultimatly.

I'll probably just give Bryan a call on all of this and see what he has to say.

 

When you check the meth kit, check the relay. I have went through 2 of them in the last year. Not sure why but they rust inside the relay and stick in the off position.

 

Will do. My meth kit is adjustable. What I might do is just turn it down a bit, then watch the wide band, and keep it safe, but run it a little more ideally to 11.5 instead of 10.6.

 

My car runs like a dog when the AFR is 10.6 even with the meth working. To be honest Brians tune needs to be leaned out in the Rpms that are rich and you need to get your meth working again. I've done Wot runs at 12.5 by accident and even on my modest 355 motor nothing was damaged. If your meth quits you will know it and can get out of the throttle because you have a wideband. Usually Brian can email you the new tune if you tell him what rpms its rich at or send him a graph.

 

Running the stock 95 PCM, I'm not sure how much he can dial it in further, as his initial tune with me shows that after it goes rich with the meth, it later leans out, and then fattens up again when the meth reaches its max spray at 10#'s of boost, then it leans back down.

 

Not sure if you can log AFR and RPM with your wideband but Brian can flatten out your AFR's as long as he know which rpms are rich and which are lean. Once you have a flat curve being commanded by the computer then you can fine tune with your adjustable meth. Log a run with you meth at normal settings and send it to him. Hit the meth a few times to make sure the lines are full before you do the actual log run. The meth has a tendency to evaporate in the lines it could be that your pump just needs priming. He just has to adjust the "PE vs RPM" table.

 

The snow kit is solid state - it doesn't have relays. To troubleshoot it, you can hook up a Mityvac to see when it comes on (assuming you have the boost referenced kit) and put your nozzles in a bucket or jug where you can see them spray. You want to tune for 12.5 or so without meth and about 12.0 with the meth. It's your choice to go richer to be safe. But if you are at 12.0 without meth and go too rich with the meth, you are probably using too much of a nozzle and losing power over not using it at all. It does protect you though, so you would have that benefit at least.

 

I run at 12.3:1 at WOT all the time, I'll even stay in it till 12.5:1, then anything past that I shut it down.

 

Everyone's got their own place they want to be at tune wise. Personally, I would not feel comfortable at ALL where you are at 12.3-12.5 running FI. N/A would be fine, but too dangerous IMO for FI.

Ideally I want to be about 11.5 on the AFR. Talked to Bryan today, we came to the same understanding that where the tune is at, is safe. I will probably just turn down the meth until the AFR is at 11.0 or so at WOT just to keep things safe. He told me this today (and I remember him saying the same thing while he was tuning it). "running more lean, and more timing might get you another 25 RWHP, but it will not be as safe". This says it all for me. I'd rather be a little on the rich side any day of the week, than run 25 more ponies to gamble on blowing something big.

 

Tuning is an "experiment". You won't know if it makes more power leaner (or richer) until you try it.

Rich

 

I run 100% meth through my alkycontrol kit. He told me that stoich for meth is 7.0 or something. So if your wideband is setup for gasoline you are not getting an accurate a/f ratio. Here is where it gets sticky.

U have to calculate amount of meth vs amount of gasoline to get your corrected a/f ratio.

Julio suggested (to me) run it rich, run it low on timing, and just put another psi or two into it to compensate.

Right now:
Stock motor
5-8 psi via boost controller
10.0-10.5 a/f on a lc1 xd16 setup for gas
17 degrees advance (looking to get 20 deg once i have a buffer of money for a rebuild)

 

Bryan also mentioned that widebands will sometimes read more rich than what the A/F actually is with meth. I am running a 50/50 water meth mix. 10.0-10.5 is even more rich than I was before. I am aiming more towards 11.0.

Everyone has got their own opinion to run either a meth mix with water, or straight meth. Personally I prefer 50/50 in my Z. Julio really rubbed me the wrong way, almost demanding that I run straight meth, not even being open minded that water and meth would work at all. That was enough for me not to buy one of his kits (even though I know his kits are good). I don't want to get into the water vs meth debate on this thread, as that was not the intent it was started for.

What I would like to know is exactly how much more rich the AFR is on the wideband due to running meth?