Higher boost and E85 or Methanol 9

[Nitr0EngiEx]

I have a mazdaspeed 3 with a built motor and a Garrett 3076 turbo. the engine is 2.4L Direct injection, and holds a fuel rail pressure at 1800 psi kind of like a diesel just not as extreme. I have 9.5:1 compression.

I want to run 400WHP Daily driver but this engine runs on 93 octane pump gas and I am spraying a 7 Gallon per hour nozzle of 50% Methanol and 50% Water into my intercooler piping about 16 inches before my throttle body.

My EGT reads about 1200 F at WOT and i run about 11.6-11.9 AFR. The turbo is flowing about 350 Grams/second of air. at 22PSI at 6k rpm. I am getting some engine knock and am very concerned about tuning the timing higher and not catching damage to the engine. I want to beat on it every day as safely as i can and i have a fully built motor so between the 93 octane gas with spraying methanol it should be enough but I don't feel it is and i do not want to spray more its terribly difficult to introduce the extra mixture of fuel into the intake tract and i cannot program the ECU to read it, it can only compensate.

The MAIN Question: E85 is NOT available around me, 99.9% methanol is available. 106 octane is available but costs way too much for daily driver. Should i just start putting Methonal in my gas tank with the 93 octane because i cant buy E85 ? what other options are there. I want to go up to 26-28 PSI and I want a more solid solution then trying to spray so much alcohol.

And What AFR Would be good for this application

*(please remember I am direct injected and my AFR runs a tad higher then the conventional port/intake manifold injections that have time to atomize pre cylinders and dont require so much fuel pressure, and have more time to spray)

 

[mattsooty]

Nitro,

I haven't had the time to read many of the posts but one thing I have picked up, and its a bit of an aside, is that you are running a wall guided DI set-up and increasing fuel delivery.

You need to be careful with this as it can put you at risk of significant bore wash, which will cause some very expensive damage. Not only that but badly set up GDI engines (in terms or inj pressure & timing) can fill the sump with fuel in a very short time, degrading the oil and causing damage throughout the engine.

MS

 

[Tmoose]

"Lead in fuel will not hurt your engine, in fact it helps some parts. One problem with introducing unleaded fuel was to prevent engine wear and premature failure."

In Kettering's biography "Professional amateur" I think he mentions that the introduction of tetraethyl lead (1920s?) was anticipated as increasing engine wear by some mechanism or another. Interesting how theory is sometimes overcome by fact.

I'm eagerly waiting for medical "science" to discover that hot salty fat is actually good for me but only when taken with mega-doses of cheap domestic beer.

 

[Tmoose]

http://www.radford.edu/~wkovarik/papers/kettering.html

"Troubles continued to test Kettering and Midgley's commitment to tetraethyl lead in the 1922 to 1923 period. The compound was extremely hard to make and it broke down quickly in the sunlight. Engine tests showed that particles of lead burned holes in the exhaust system and valve seats. Lead oxide also caked onto spark plugs, stopping the engine after a few thousand miles. "

 

[patprimmer]

To run leaded fuel, they had to incorporate lead scavengers as well as the lead to avoid lead build up from fouling and clogging things.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[thruthefence]

Here's the one we use in the recip helicopter;

http://tinyurl.com/4344v5r

 

[evelrod]

Apples and oranges. You simply cannot compare modern leaded racing fuels or, for that matter, the leaded fuels of a few decades ago, with the Ethyl Premium of the 30's vis a vis "lead content". I remember fouling plugs in my '49 Merc a couple times but nothing like what my dad told me of the early days.

All to PC for me. I've washed so many parts in leaded fuel and handled so much lead that, if you can believe all the hype, I should have died long years ago. However---I'm still here and still using leaded racing fuel.

If your using an Okie credit card, the "new gas" tastes better than the old leaded stuff....;o)

Rod

 

[TDIMeister]

A couple of things you can try to mitigate knock before opening the engine up to reduce the CR. First, 11.6 AFR is extremely rich; that's equivalent to about Lambda 0.79 on gasoline. Further, I assume that you are calculating AFR based on gasoline only. Methanol has a very different stoichiometric AFR (6.5:1). It is best to calibrate using a wide-band O2 sensor and quote lambda rather than AFR because AFR can vary greatly depending on your gasoline/methanol mix (stoichiometric AFR of M30?12.7; M50?10.2; M85=7.3)

Furthermore, DISI engines operate with quite different needs wrt knock-limited and MBT AFR. They operate best with mixtures rather closer to stoichiometric than old PFI/carbureted engines. Even the Audi R8 turbocharged FSI LeMans racing engines before the Diesel era were running closer to lambda 0.85-0.93 at full-load on gasoline.

Blending some methanol in the fuel tank will raise the octane number of the blend, and also the very high latent heat of vaporization of methanol will help charge cooling. Direct injection magnifies the charge cooling effect. Just make sure that the fuel system components are compatible with MeOH. If this is OK, I would suggest running the tank to near empty and splash blend a small amount to about ~M50 start to start. Calculate your fuel use carefully and observe knocking tendency and progressively add more *pure gasoline* until you are at the threshold of knocking; determine the percent MeOH at that point and that's about where you should be running. Lambda should be brought back up to the aforementioned ~0.85 as a starting point, however. When you run higher MeOH percentages, you will need a higher injector flow rates to maintain a given lambda at the same pulse width duty cycles, so keep this in mind).

One other thing you can do is if your engine has mapped computer-controlled cam phasing, you can try to retard the intake camshaft. This will have the effect of reducing the effective compression ratio and operating on a pseudo-Miller cycle. If you have a limited adjustment range, you could try to retard the timing by physically moving the camshaft by one tooth in the retard direction (re-indexing the cam position sensor accordingly) and also adjusting the phasing map so that you don't have such late IVC when you don't want it (e.g. at low load, low RPM).

There's no reason why a DISI, 4-valve pentroof head cannot retain a 9.3 geometric CR with the amount of boost you are running. It's a simple calibration issue.

 

[Lou Scannon]

TDIMeister, I agree with all your points, however, any Miller cycle effect will proportionately reduce IMEP, BMEP and hence torque and horsepower. Now if the engine and turbo are up to it, boost could be raised to compensate, theoretically. But I think Miller cycle is not often used when the quest is to optimize specific power unless there are severe constraints on thermal efficiency and/or engine-out NOX.

I forgot what I was going to say

 

[BrianPetersen]

Regarding cam timing effects, a lot of the muscle-car engines back in the day, and sport motorcycle engines nowadays, get away with 13:1-ish nominal compression ratio simply because they are running so much cam that at lower revs, the volumetric efficiency is lower, so there is less effective compression (and less output torque).

At higher revs when the engine starts coming "on the cam", detonation is less of a problem anyways.

Engines in those applications are designed to make power with revs, not stump-pulling torque off idle. In a drag-racing car, you use a torque converter with a really high stall speed ... having torque off idle doesn't matter much. In a roadracing sport-bike, the rider keeps the revs high, in the powerband. In a heavy(ish) car with a manual transmission, absence of low-end torque (relative to top end power) could get rather annoying.

I agree with the other comments that your thick head gasket solution is the wrong thing to be doing; you need whatever squish you can get.

 

[TDIMeister]

Retarded IVC need not experience a loss in performance (at least compared in magnitude to having to drop x PSI of boost and y degrees of ignition timing on account of knocking). If the intake is properly tuned, the charge backflow from late IVC can be minimized or eliminated where an overpressure-wave arrives at the intake valve just before its closure and you still benefit from the delayed start of compression and reduced effective CR, which can be easily seen on a log p-log V plot as the point when the compression stroke follows a pretty much straight line with the slope being the polytropic exponent coefficient.

Forced-induction race engines by virtue of radical cam timing run a de facto Miller cycle (minus the late EVO that makes it a true Miller).

 

[Lou Scannon]

At best then, we're talking about mild Miller cycle, as a band-aid solution for a CR that is too high for the power objectives, which is fine. An optimized CR would yield better power density. An aggressive Miller cycle, applied as intended, has a very high CR in order to realize a high effective expansion ratio, and has significantly delayed IVC in order to avoid knock. The power density that is lost due to lower volumetric efficiency is offset by higher boost and higher thermal efficiency.

I forgot what I was going to say

 

[TDIMeister]

BrianPetersen wrote: Regarding cam timing effects, a lot of the muscle-car engines back in the day, and sport motorcycle engines nowadays, get away with 13:1-ish nominal compression ratio simply because they are running so much cam that at lower revs, the volumetric efficiency is lower, so there is less effective compression (and less output torque).

At higher revs when the engine starts coming "on the cam", detonation is less of a problem anyways.

Not forced-induction and only partially germane to the discussion, but Mazda's SKYACTIV-G is basically a Miller-Atkinson cycle with late IVC, allowing the engine with 14:1 compression to survive with pump gasoline. I suspect heavy full-load enrichment, especially near the max. power point but that's not an operating point in certification drive cycles.

http://www.mazda-news.eu/2011/05/31/skyactiv-g-petrol-engine/

 

[charlotte49ers]

Nitro, could you post a pic of your mazda (engine)? I am always curious of mazda's running turbos

 

[zcchene46]

If possible, run E85!

 

[AndrewHod]

I was reading an old book that mithyl alcohol (methanol) can be used in a petrol engine. 1 needs 2 times as much fuel (to air) but get 11 mpg instead of 20 but, as it is made of ½ oxygen, produces less pollution. As it has an octane N° of 130 it could use the same compression ratio as a Diesel engine. As Diesel engines have no spark plugs then some ignition chemicals could be added to the methanol; they only work with a warm engine. So an engine could be started with Diesel & changed to methanol when more power is needed. Then back to Diesel when not much power is needed. That could be more economical than using a larger engine. Has this ever been tried?

 

[FeX32]

I am not nearly as knowledgable as the other engineers on this subject.
But, I just wanted to say (Since I own a mk6 GTI)

Too bad APR is only for VAG cars. For a few grand you can get 450 whp from a 2.0 TSi/FSI engine installed and with proven reliability.





Fe

 

[Lou Scannon]

AndrewHod, your post is filled with non-sequiturs that render it technically unhelpful, and throw into question your qualification for posting, other than questions, in this forum.

Fex32, I agree with your first sentence. The remainder of your post is cryptic, superficial and unhelpful, since you have thrown in 4 TLA'a (three letter acronyms) that are not commonly known (correct me if I'm wrong), and I don't see how it relates to the OP.

I forgot what I was going to say

 

[FeX32]

hemi,

I never meant to offend anyone here, particularly the other respected members like yourself. And I expect the same respect in return. I have my own engineering expertise to which I am surely extremely knowledgeable about (I won't go right out and say what I mean here...). I already acknowledged your good knowledge on this subject and still stand by it, as I have respect for it.
My post was not meant for you.
The OP is surely familiar with the acronyms as he is obviously a sport tuner (not an engineer) and knows the long rivalry between MS3s and GTIs.
I happen to be a GTI owner and know many MS3 owners. I thought I might put a bit a advocacy in this thread..... although not helpful technically it is relavent....(if not to at least make the OP chuckle )
If you are wondering why I am reading this it is to learn for myself outside of my regime.
Feel free to think otherwise.
With all due respect intended,

FeX32


Fe

 

[FeX32]

Oh and I can't be 100% sure that the OP is not an engineer.
I apologize if you are an engineer Nitr0EngiEx.

To add to the above post, I think my reputation thus far on this forum has proven some of my spare time is full of witty engineering . To which I am glad to be a part of this forum where I can help others with engineering problems whilst at the same time read and learn others ideas and situations.
During the day I am a research engineer at a robotics institute.


Fe

 

[Lou Scannon]

No worries Fe, I'm certainly not offended and by this forum I only meant Engine & Fuel Engineering and meant no offense to your electrical qualifications. Your mature & restrained response to my challenge is commendable. If you could clarify the acronyms you used above I'm sure many of us would be grateful. By all means, stick around, learn, ask, & contribute.


I forgot what I was going to say