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-   Methanol/Water Injection (https://www.miataturbo.net/methanol-water-injection-22/)
-   -   How many PSI of boost with meth? (https://www.miataturbo.net/methanol-water-injection-22/how-many-psi-boost-meth-10408/)

Piranah 06-05-2007 09:59 PM

How many PSI of boost with meth?
 
I just wanted to know from those of you out there who are running a stock long block and a gt25 or gt28 intercooled turbo setup and WI, how many psi of boost are you running? just trying to get an Idea of where I should set mine at.

neogenesis2004 06-05-2007 10:13 PM

past 15psi and you have to start worrying about the stock rings longevity. The rest is in the tune.

Piranah 06-05-2007 10:28 PM

The car boosted 7psi just fine without the methanol, is there any safe amount that I can increase the boost without retuning it?

Kelly 06-05-2007 10:28 PM

300 whp on pump gas should be doable.
Provided you have the fueling handled, 10 psi without pulling any timing will be a piece of cake.

Piranah 06-05-2007 10:31 PM

^^^Really?! 300whp with just a gt2560r, meth and a tune? are there people who have done that safely before? (on a stock longblock)

jwarriner 06-05-2007 11:53 PM


Originally Posted by neogenesis2004 (Post 120755)
past 15psi and you have to start worrying about the stock rings longevity. The rest is in the tune.

Considering the rings withstand the cylinder pressure during combustion, how can you put a boost rating on rings in psi?

neogenesis2004 06-06-2007 12:04 AM

then by all means go for broke, tell me what happens.

Joe Perez 06-06-2007 12:23 AM


Originally Posted by jwarriner (Post 120774)
Considering the rings withstand the cylinder pressure during combustion, how can you put a boost rating on rings in psi?

More boost = more fuel to burn = higher pressure in the cylinder on the combustion cycle.

In very simplistic terms, the reason that the turbocharged engine is making twice the power is that twice as much force is being exerted on the pistons, and thus the rings.

jwarriner 06-06-2007 12:36 AM

That clears it up. Short answer: he's right, long answer: it's actually power that hurts the rings. Thanks.

Kelly 06-06-2007 01:31 AM

Lets say 270 whp since you are running a smaller turbo.

Lex 06-06-2007 01:31 AM

rods will break before you have ring problems.

Savington 06-06-2007 04:10 AM

Not if the tune is good. If the tune is good, the rods are good for more power than the rings. The rings fail from cylinder compression and not boost. Once I get my setup running and tuned on 12psi, I'm going to jump to 18psi and use WI to control detonation and intake temps. Hopefully I can see 250-270rwhp. It'll be stretching the small turbo, but with WI it's doable. The boost doesn't kill the rings; the pressure does. 12psi out of a GT32 vs. 12psi out of a T25 are different animals.

magnamx-5 06-06-2007 08:31 AM

i havwe run 15-17 psi on my small 16g wich flows a hell of a lot more than your 2554 you will need to add timming and adjust fuel accordingly but there is no limit to what WI can do provided you set it up for the job and keep it supplied. I plann on more than 300 whp on mine with pump gas and No IC. I have a 40 overbore and some wiescos becouse i was to gready last time and didn't lift. but other than that all is good. I suggest you read the faqs by myself neongenisis, Ben etc and experiment with it we all offer up different tunning strategems but they are all essentialy the same. GL

Piranah 06-06-2007 12:30 PM

Well I have some people telling me that just because I ran 7psi w/o WI, doesn't mean that I can just jack the boost up to 12psi with WI. I thought that because Methanol injection stabilizes the fuel to that of near race gas levels, and helps prevent pre-ignition means that as long as my AFR readings are normal, I can jack up the boost another 5psi without having to change timing or fuel levels. Am I right, or is retuning absolutly neccessary?

Kelly 06-06-2007 01:13 PM

You ABSOLUTELY need to make sure the fuel is there. You MAY be able to leave timing alone or retard conservatively AS LONG AS YOU HAVE ADEQUATE FUELING.

magnamx-5 06-06-2007 05:25 PM

retune it is not that hard. you cant just throw on the kit as it comes and try 12 psi you need to check your varius pressures and feel it out 1 psi at a time.

Piranah 06-06-2007 07:44 PM

I was just think about hooking a wideband up to it and increasing the boost until I get to somewhere like 12.5:1 and calling it a day.

magnamx-5 06-06-2007 09:04 PM

listen for knock etc this will do the job just fine i tuned just fine before my WB with stock ecu. Watch the Oil pressure gauge for twitching this is indicative of knock.

Kelly 06-07-2007 01:07 AM

Don't do anything without a wideband. I would recommend picking up one of those before water injection.

Piranah 06-07-2007 02:47 AM

Well, it's already running the WI. I was going to get the Innovate LM-1 for use in both the Miata and the WRX, but I won't be able to get it for another 2months.


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