OK well I thought we could start posting our boost and timing data to help each other out ...I am running a 9 turbo in california (91 octane) with 100% Meth and mods in signature. I have been playing with boost and timing with the hopes of finding the optimal mix for power. Right now I am peaking around 28 at 4100 rpm and tapering to 21psi at 7400, but am still seeing some knock around 6K rpm so I may need to take another 1 psi out.

My timing goes from ~4* (in the 3800 area) to 14* (7400)

AFRs are ~10.8 to 11.2

So any thoughts? Do my numbers seem off? Am I just blowing lots of hot air ? Should I decrease the boost to 27 tapering to 20/21/22? Should my timing be much higher?

(I posted the same post in the Engine section, but I did not get a sense from the responses that folks were running Meth or 91 octane. For those of you that are running 91 and Meth, would you please help me out...)

Thanks in advance

 

I run meth with 92 octane but basicaly it really dont matter if its 91 or 92 since the meth is increasing it by at least 4 points.
you timing is WAY WAY WAY to conservative, you need to bump it up to around 20+ boost at least 25psi.
I use around 60/40 meth/water and I boost to 27-28 with around 6* 3500 RPM
and around 22 by redline.

 

I am just curious. Doesn't the stock turbo start to become ineffiecent around 25psi?

 

Not according to the dyno numbers and track times from people running 30psi.

I do think running higher than 25psi removes some of safety margin. Might be alright for a night at the track but for a daily driver I wouldn't risk (punish) it.

On 110 octane I run 8* peak and 20* at 7800 while attempting to hold 25psi.

 

Jeff -- You are holding 25 psi at 7800 with 20* with no knock ??? Wow! I know 91 + 100% Meth is not the same as 110 octane, but I thought it was close...there is no way I could be at 25psi and 20* @7800 on 91 and Meth ....

Also, for folks running Meth + H20, do you distill the water?

 

CJ I'm running basically the same numbers as you are, only thing is here in Jamaica we have 90 at the pump...I'm peaking at around 28psi, timing is ~4* at peak (3500-4000) and ~14* by redline. Only thing is I'm running a little leaner than you, 11.2-.3 during peak and ~11.6-.7 from 5000>
I'm using 50/50 mix and yes you should use distilled water. My next approach is to run a little richer, drop a psi or 2 and see if I can run some more timing. Haven't determined yet if my car likes rich/advance or lean/retard

Jeff - how do you get the stock turbo to hold 25psi up top? I've tried preloading my actuator fully, forge DV, turned down my EBC to not spike so hard and nothing works...still falling off to around 20psi up top. Whats the secret

 

^^ Thanks a ton for the information....I guess for those of us with crappy low octane gas, the best we'll do is ~28psi peak and a taper to 21/22....As for 25psi and 20* @7800 on a stock turbo -- I have no idea how that is possible, but hopefully Jeff will answer...

 

I don't see 25psi at 7800. As stated I attempt to hold it which means setting my duty cycle as high as possible.

I do run 20* at 7800 with maxed out boost when on good race gas.

From my DSM days and when I ran alchy on my 03 .... I never saw gains from distilled water. It would allow for more timing and boost but HP didn't improve over straight alchy or straight meth.

If I was forced to run 91 octane I would probably scale back the 91 fuel table and add a larger nozzle for 100% meth.

Are you using a 7# or 10# nozzle?

 

Well, from my first round of testing it appears that my car likes 100% meth better than 50/50 -- I was able to run more boost and timing with 100% meth.

I wonder what that means: (1) my intake charges need the additional cooling, (2) 91 is just too prone to pressure pre-ignition, or (3) my cylinder walls were really not that hot ??

Also, Jeff, sorry for misinterpreting your post and I am running an MW10 nozzle.

 

I always had best results with 100% alchy as well. Water is good for cooling but if you don't need it then its useless.

 

I think I need to try 100% meth...I know I have crappy gas here (90 octane) but I thought I would be able to run a little more timing/leaner AFR when compared to my pump gas map (I'm only about 2-3* more advance and 1/2 point leaner across the board) however, I am running 28psi vs 23psi pump. Am I expecting too much?

 

Raas -- It sounds like we are in similar situations and are reaching the limits of 90/91 octane. I am still running a catalytic converter and wonder if that is hurting a bit. At lower boost levels I found that I was able to achieve the same results with and without a catalytic converter, so I kept it on.

I am still testing the 50% water combination and have changed my ignition and MIVEC maps to see what I can get out of the car.

You could try increasing your boost from 28 to say 30 (which will give you a bit more mid-range torque), but from what I have seen and tested, we are at the turbos limit on the top end (~21/22 psi). If you increase boost, you'll likely need to pull some timing, so it may only add a few hp...

 

Yeah I know what you mean cij, sucks that we don't have better gas. Definitely going to try turning up the boost a little more and see what I can get out of it. Based on the feedback I've gotten, running 50/50 is the best way to go especially since we run crappy gas, the knock suppressing ability of the water is really helpful, but it's just like Evan said, if you don't know how to extract the power from injecting water then its going to seem pointless.
The other issue I'm having now is knock after back to back logs. I'll make an adjustment, do a 3rd gear pull and the it would be knock free...back off and do another pull and it knocks all over. I'm going to assume that this has to do with heat soaking and possibly reaching the efficient flowing capacity of the stock intercooler. But then again there are others on this forum that have done so much more with the stock intercooler, so i really don't know

 

Raas -- Well the back to back no knock and then knock sound like heat related issues. I too struggled with that, but I am not sure it is the intercooler. I am changing some MIVEC settings and will let you know how they work out. Best of luck

 

nice thread i am thinking of head to meth/water on my car.....
gas is 91 octane as well....

any ideas cj, raas seems like u guys played with it a lot as well