I am going to go to the track this wednesday if everything goes well. I have my car running on 91 oct and meth injection (HEET) with a M15 nozzle. My afr's are at about 11.5-11.7 with no knock. Car runs fine. I want to run higher octane gas at the track possibly 118oct...My question is will my car run bad with 118oct and meth inj. (M15 nozzle)??? Car won't bog out or anything?

Why run more octane (mor expensive) fuel when you are getting no knock. Do you plan on chaning your tune at the track?

dsm-onster said:

Why run more octane (mor expensive) fuel when you are getting no knock. Do you plan on chaning your tune at the track?

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Agreed. If you are seeing no knock on your current tune then the race gas will not provide any benefit, unless as mentioned you plan on turning up the boost or advancing your timing for the race. Especially if you are injecting straight methanol, the race gas is just not needed. But it's your $$.

No need for the race gas. One of the great things about meth injection is that you can run a race-gas style tune all the time. Also, that you can tune the car in on the street over time and run it in the same state on the track.

Oh ok, thanks guys....I gotta say that the HEET goes work great. the only thing is that all the auto parts stores are selling out of that stuff since its not winter anymore...I don't think I am going to up the boost anytime soon...24-25psi is more than enough for me.

M15 with a 14b? Thats like shooting a bazooka at an ant!

Yeah an M15 seems almost too much, if your running 780cc injectors.

DSM4me44 said:

Yeah an M15 seems almost too much, if your running 780cc injectors.

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Injector size has nothing to do with detonation control.
I don't at all feel like doing the IDC% with an M15 on a 14b at 30lb/min and 780cc, I want to see those fuel settings. I'm "gessing" 35% IDC at 12:1 A/F

The calculator used to determine the injector size is, your

duty cycle times 4 divided .15 or .2 i can't remeber exactly which.

If your duty cycle is close to 100% you can take your injector size x 4 divded by .15 or .2 then.

scottsee said:

M15 with a 14b? Thats like shooting a bazooka at an ant!

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I actually had an M3 nozzle back when I was running the 14b...I was injecting straight H2O with the M3 nozzle, 14b, 780cc, and 20psi when I ran the 12.6

I upgraded the nozzle size after visiting FFTEC and getting alittle advise from Sean. I am running the M15 with the GT30R.

HustlerTalon said:

I actually had an M3 nozzle back when I was running the 14b...I was injecting straight H2O with the M3 nozzle, 14b, 780cc, and 20psi when I ran the 12.6

I upgraded the nozzle size after visiting FFTEC and getting alittle advise from Sean. I am running the M15 with the GT30R.

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Just curious if you're still running straight water with the M15? How well did the straight water work for you with the M3?

romeen said:

Just curious if you're still running straight water with the M15? How well did the straight water work for you with the M3?

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No. I am using HEET, yellow bottle (methanol that I bought at any autoparts store) with the M15 nozzle.

The straight water worked fine with the M3 because according the the datalogger I was using back in the day, it said I had no knock boosting 20psi on my stock 14b turbo.


here is my video of the M3 nozzle and how much water it injects...ignore the dripping water and the pulse of the pump...I fixed those things long time ago.

http://www.youtube.com/watch?v=nTARML7ROGE

HustlerTalon said:

No. I am using HEET, yellow bottle (methanol that I bought at any autoparts store) with the M15 nozzle.

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OK, that makes sense. How does running straight meth with the M15 compare to your previous setup? Any obvious pros and cons?

Good info BTW.

romeen said:

OK, that makes sense. How does running straight meth with the M15 compare to your previous setup? Any obvious pros and cons?

Good info BTW.

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Right now with the GT30R, I can only run about 17-18psi without getting any knock....with the methanol I can run up to 25psi with no knock....oh yeah and keep in mind that I am running that with the crappy 91 octane gas.

After going back and rereading your previous posts I realized that you have already answered most of these questions.

Thanks again.

When i tuned my car with 50/50 water / meth i was able to get a little more timing out of it and lean it out of about 11.4/1 afr. I recently tried straight meth from a supplier and, on top of my old tune, was able to lean it out closer to 11.9/1 afr and get 4 degerees more of timing via dsmlink with less than 3 counts of knock (that is with the m7 nozzel). In my opinion, straight meth is the way to go. I'm not gonna lie, with my afr's like that and such aggressive timing, it get scary.