Methanol/Water injection?
04-11-2012, 05:19 AM
#1
Three Wheelin'
Thread Starter
Methanol/Water injection?
Has anyone gone the route of increasing compression via head machining/piston shape to lets say 11-13:1 (NA obviously) and ran methanol/water injection to control compression heat (detonation)?? The problems i could see are:
-methanol and aluminum (not compatible AFAIK)
-locating an injection point that will not affect homogenous A/F mixture
This is very basic but i just don't see any high compression NA 928 motors out there, they've all gone the opposite route with forced induction. I don't see any reason why you couldn't go 12 or 13:1 CR with alcohol/water injection that is controlled by it's own module (just like pulse width). In fact, there are modules from Snow Performance that control flow (or pulse width) by using a 5V reference from the MAF (or theoretically any other engine 5V ECU input (coolant temp/IAT etc))
The only thing is that with this, it's pretty much irreversible in that in order to drive the car with the original engine, you have to be either running alcohol/water injection, or running race gas. That's a big downside for selling the car on some day... but ya.
-methanol and aluminum (not compatible AFAIK)
-locating an injection point that will not affect homogenous A/F mixture
This is very basic but i just don't see any high compression NA 928 motors out there, they've all gone the opposite route with forced induction. I don't see any reason why you couldn't go 12 or 13:1 CR with alcohol/water injection that is controlled by it's own module (just like pulse width). In fact, there are modules from Snow Performance that control flow (or pulse width) by using a 5V reference from the MAF (or theoretically any other engine 5V ECU input (coolant temp/IAT etc))
The only thing is that with this, it's pretty much irreversible in that in order to drive the car with the original engine, you have to be either running alcohol/water injection, or running race gas. That's a big downside for selling the car on some day... but ya.
04-11-2012, 10:39 AM
#2
Rennlist Member
Has anyone gone the route of increasing compression via head machining/piston shape to lets say 11-13:1 (NA obviously) and ran methanol/water injection to control compression heat (detonation)?? The problems i could see are:
-methanol and aluminum (not compatible AFAIK)
-locating an injection point that will not affect homogenous A/F mixture
This is very basic but i just don't see any high compression NA 928 motors out there, they've all gone the opposite route with forced induction. I don't see any reason why you couldn't go 12 or 13:1 CR with alcohol/water injection that is controlled by it's own module (just like pulse width). In fact, there are modules from Snow Performance that control flow (or pulse width) by using a 5V reference from the MAF (or theoretically any other engine 5V ECU input (coolant temp/IAT etc))
The only thing is that with this, it's pretty much irreversible in that in order to drive the car with the original engine, you have to be either running alcohol/water injection, or running race gas. That's a big downside for selling the car on some day... but ya.
-methanol and aluminum (not compatible AFAIK)
-locating an injection point that will not affect homogenous A/F mixture
This is very basic but i just don't see any high compression NA 928 motors out there, they've all gone the opposite route with forced induction. I don't see any reason why you couldn't go 12 or 13:1 CR with alcohol/water injection that is controlled by it's own module (just like pulse width). In fact, there are modules from Snow Performance that control flow (or pulse width) by using a 5V reference from the MAF (or theoretically any other engine 5V ECU input (coolant temp/IAT etc))
The only thing is that with this, it's pretty much irreversible in that in order to drive the car with the original engine, you have to be either running alcohol/water injection, or running race gas. That's a big downside for selling the car on some day... but ya.
My old GTS race engine was running 11:1 on Shell V-Power 100 without any issues. The new iteration of this engine is 5.5ltrs, 12:1 compression via JE pistons and ITBs. Will run it on Shell V-Power 100 with Bardahl fuel additive. Don't expect any problems as it will be Sharktuned properly.
Will post updates as to when we start her and take her to the dyno and open road.
Alex
04-11-2012, 11:04 AM
#4
Three Wheelin'
Thread Starter
Sounds good. How much head material can be removed to raise CR without running into valve clearance issues assuming all stock spring installed height etc?
04-11-2012, 11:06 AM
#5
Rennlist Member
That funny RON/MON thing... 100RON is what... 95MON? Roughly of course... 100 octane RON here is the highest we get. Aral in Germany (BP subsidiary) sells 102 octane RON for the price of 100 octane, but I only get to drive the Nurburgring twice a year these days...
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04-11-2012, 04:03 PM
#8
Rennlist Member
you wont run into valve clearance issues, with head shaving. its already an interference engine. this why the engine needs to be set at 45d BTDC to rotate it with the cams in place and no belt. i guess you could do the calculations of what the max limit would do to compression. it might take a few CCs out of the combustion chamber and the cam pulley timing marks willl then be a little off too. the 6.0 liter im driving on the street (street car) has had a big shave, and is fine. mine had a little shave and is fine too, but has custom 6.5 liter pistons
