engine rebuild and fuel economy mods

[bhearts]

amazing thing is! i have a brand new megasquirt 3 just chilling around. i was gonna put it on my 280z but i was stuck in the land of v8 dreams. so i couldnt commit. but i could for sure see putting it on the aspire.

[bhearts]

so my plan is to find a jy b6 motor from a 88-89 car. i was looking into the miata high compression pistons that ive heard a couple members talking about. if i was to install these and boost my compression to 10-1 and up...whats gonna keep my motor happy in the form of fuel. ethanol based fuels are redily available here in kansas, and theres even a station that offers mixes from e30 to e85. but....what if i just ran regular pump gas with this high compression build. and built a stepper water meth injection kit. one that would vary (pulse width mod style) with the rpms (im an electronics tech...shouldnt be too hard).
all the turbo guys claim "race gas performance and reliability on pump gas" with water methanol mix 50/50 by weight. why cant i run this in my n/a motor to resist knock. ive heard a couple people talking about not building high compression motors because of fuel quality reasons and this sounds like a great compromise. mix this with some steam injection and i think i have the recipe for 50 plus mpg and a 90 hp motor. who could say no to that.

[FestYboy]

miata pistons won't play nice with a B6 head... and a little head work to a 1G B6 will put you in the 100 HP range and still be able to pull 40+ mpg with no other mods. water or meth injection is just an extra and you SHOULD be able to pull 11:1 on 87 oct with your megasquirt and a good tune.

[Advancedynamix]

Yes the water injection will allow you to run higher than normal compression, and it will actually effectively raise your compression ratio (water doesn't compress), and the megasquirt can be used to efficiently inject the water solution as well.
Arty, you can get away with 11:1 on 87 in these engines? Huh. That's impressive. Props to Mazda on a good chamber design.

[getnpsi]

A turbo increases air and fuel at the same time. Alcohol fuel with the compressed air creates an evaporative cooling effect for the knock suppression that doesn't equate the same to higher compression n/a engines. It does help don't get me wrong, you can advance the heck out of the timing either way vs regular pump gasoline but with tuning with the turbos it IS like magic and not exaggerated at all.

My dodge runs rich from the factory (stage upgrades even more rich) and we would get the mix to like e30 and change nothing. It would lean out to not a dangerous level and provide knock suppression as we only have 91 at the pump. Liquid schwartz to a certain effect. This is 99% caring about dyno bragging and taking off .5 second on a quarter mile, not increasing driving range.

With megasquirt systems you can actually have the o2 sensor report a different voltage so around town you can get the car to idle leaner and in light throttle conditions. The water injection or alcohol fuel will address the problem with knocking in the case a lot. Around town is where you really pick up mileage, so one voice is telling me how would a 1.1L do with its own engine work vs a higher displacement at its own optimum build. a b6 can get out of its own way in a festiva, allowing you to lug it more, and a 1.3 or worse you really have to time everything right on a commute with changing terrains or its toilet MPG real quick.

IIRC there was an episode of UK top gear where a bmw M was chasing/leisurely following a mpg minded car going full bore and they both got 19 avg mpg around a racetrack.

[TheresGabe]

IIRC there was an episode of UK top gear where a bmw M was chasing/leisurely following a mpg minded car going full bore and they both got 19 avg mpg around a racetrack.

It was an M3 with a Prius following at 60MPH around the track. Actually the BMW delivered 23mpg to the Prius 19. Electric/hybrid cars are only efficient in traffic/stop and go situations.

[blkfordsedan]

I agree, I think 11:1 is do-able on pump gas...especially 91 or 92 premium. Heck, the B3 is almost 10:1. The aluminum head is a huge help, plus the chamber design is good. The plug is close to the middle and these motors don't require a lot of ignition advance anyway. If you polish the chambers, 11:1 should be achievable with proper timing and pump gas.

[mattdickmeyer]

Also, don't put epoxy in your combustion chambers. Has it been done? Yes, does it have a high success rate? No, not at all. If epoxy was an acceptable way to permanently reshape combustion chambers then I wouldn't have spent so many years welding heads.

Just simply having the head surfaced about .020" will increase your squish area and promote better swirl along with the higher comp ratio ( and more sensitivity to detonation). This with some gapless second rings will boost the engines VE alone. Also, gapless second rings are a good idea with steam injection as well. Steam increases cylinder pressure and causes ring blowby as well as breaking down the engine oil faster.

Just a friendly bit of information, I read quite a few comments that include mixed & matched facts & phrases. Decking the head will have no affect on squish area as the squish is the distance between the piston top & the cylinder head deck, surfacing the block or using a thinner head gasket will reduce squish or "quench" clearance. Having flow benched the B3 head before every modification I did, I found that the combustion chamber in stock form promoted too much swirl which is good for low RPM cylinder filling, but actually restricts higher RPM air flow which will keep an engine from producing higher levels of HP, so increasing the swirl would be counter productive to say the least. I actually picked up 18% of over all air flow by enlarging the combustion chamber specifically around the intake valve. Another thing is, I read alot of you guys talking about "VE" like it is something that can be adjusted on the fly, "VE" is simply the difference between the calculated and actual amount of air that fills a given cylinder. As a tech note, gapless second rings are pointless. I hear all the time people talking about 1st & 2nd compression rings, this is very inaccurate. Think of it like this......the top ring is a compression ring, the idea is (engine builders spend years on this) getting the gap as tight as possible without actually touching, of course different applications require different end gaps. The second ring should be thought of as an oil ring (kind of like a squeegee) to scrape off excess oil & disperse it around the cylinder. If you are using the second ring as a compression ring, than your top ring gap is too loose, this will increase compression leakage which allows oil contamination in the combustion chamber, & burning oil can cause detonation & is over all counter productive in producing power.

[Advancedynamix]

Um... VE can be adjusted on the fly. That's what throttle valves are for. Lol.
I recommended the gapless second rings, not for compression, but because the OP stated an interest in steam or water injection. I am speaking from experience when I tell you they help in this circumstance, several thousand hours of it actually. I have done extensive testing on an engine dyno, in a lab environment on the race track and the real world with water injection, both in steam form and ambient injection with and without alcohol
Both water vapor and methanol are very detrimental to some of petroleum based oils most useful characteristics. Gapless secondary compression rings help to keep the water and methanol from breaking down the oil that that lubricates the piston skirts. The gapless rings do this for gasoline as well, but since gas and oil play fairly nice together it's not as noticeable. I don't suggest using gapless top rings, because the top rings take the bulk of the compression load and may become unstable if modified with the grove. Again, this is not what I have heard, it's what i have seen c first hand ( I do build engines in the same town totalseal rings are stationed.
As far as the squish is concerned, I didn't state the cylinder head deck adjusted the squish depth, I suggested it might adjust the squish area (as it does on Mazda4valve heads). Increasing the squish area has almost always benefited the fuel concious water injected engines that I have dyno tuned. Again, not what I have heard. Squish isn't a trick for ultimate hp in most 4 stroke engines, but if the OP was going for an ultimate HP build my suggestion would be to use a different engine. I have never modified a b3, and don't claim to have, and I do admire the amount of time Matt has put into optimizing these neat little engines, but the info I give is not normally that misinformed lol.

[iceracerdude]

I've got a (89) b6 (in a 97 aspire) running with stock compression, with a K03 turbo and a "CoolingMist Varicool II" Meth digital meth injection system.
So basicaly, I've got 90% of what you're interested in, minus the megasquirt. Forget the steam, the water meth mix keeps it super clean...ask me how I know.
I'm not going to be racing it anymore (first place 2010 season, first place 2011 season, No racing for the 2012 season because of lack of ice).
I was going to put it back to just a stock b6 (pulling the turbo and meth injection off) and use it as a winter grocery gitter
...but I could be induced to sell it to U. Here are some pictures:





This manifold V has replaced the one seen in the pictures ^ (schedule 10 304 stainless)



You'll be able to do this to 2.0 liter cars, but of course, your mileage may suffer for it Bwuhahaha.

[blkfordsedan]

Having flow benched the B3 head before every modification I did, I found that the combustion chamber in stock form promoted too much swirl which is good for low RPM cylinder filling, but actually restricts higher RPM air flow which will keep an engine from producing higher of HP, so increasing the swirl would be counter productive to say the least. I actually picked up 18% of over all air flow by enlarging the combustion chamber specifically around the intake valve .

Nice to see you back. I'm glad to hear this fact. When I did my B6 head, I ground back the wall that surrounds the intake valve. I angled it back quite a bit and increased the clearance between the valve head and wall from .060" to .150" at full lift. I was trying to unshroud the valve as much as I could without increasing the chamber volume too much and killing compression. I took about 2.0 CC's of material out, mostly off this wall. In stock form the wall is basically straight up from the valve seat, encompassing almost half way around the valve. It seemed to me that it had to seriously reduce air flow....so I took a gamble and ground it back at about a 10deg angle from the valve line. I was able to reduce the chamber volume back down to the previous level by milling the head .020".....so I figured it was a good compromise.

Will I gain much from this, or did I screw it up?

[mattdickmeyer]

In a case like this I would always give up a little compression to increase air flow through the camber. The small reduction in static compression is nil when considering the increase in (dare I say) volumetric efficiency, offered by the heads increased airflow ability. As for the other conversation, throttle valves or throttle stops wasn't what you were talking about, you said gapless 2nd rings would increase the VE. As for Total Seal, there is a major reason why they stopped development on gapless 2nd rings & focused on gapless top rings. Call Total Seal, ask for Joey Moriarty (the owner), & discuss your thoughts on water in the rings. Knowing him, he would probably laugh & ask what the heck do you have water in your cylinders for. Water injection has become popular in the last few years as most all cheap add-ons are, but as I am sure you will notice water injection is rarely used in major racing venues. It does have some advantages, but the fact is, the disadvantages out weigh these. As the HP dramatically increases in the engine, water injection has been found to pit valve faces, valve seats & cylinder bores. What we find is most street enthusiast tend to think, if a little is good, a little more is better & that is when damage occurs. If you will be in the Indianapolis area Dec. 6-8, I will be a guest speaker at the IMIS (International Motorsports Industry Show) discussing engine technology. Maybe some local members could attend.

[iceracerdude]

Water injection has become popular in the last few years as most all cheap add-ons are, but as I am sure you will notice water injection is rarely used in major racing venues. It does have some advantages, but the fact is, the disadvantages out weigh these. As the HP dramatically increases in the engine, water injection has been found to pit valve faces, valve seats & cylinder bores. What we find is most street enthusiast tend to think, if a little is good, a little more is better & that is when damage occurs.

Yeah, water/meth injection became popular in WWII, when it was discovered on downed German aircraft. Then It became obvious to our engineers, when it got retrofitted to our aircraft, that it potentially doubled the exsisting HP. Big ah ha moment upon discovering why some of their planes could out climb/ out accelerate ours.
Now back to the future, where you "notice" it's rarely used in major racing venues, that's simply because it's been taken away by the governing bodies like nascar and the WRC because it makes too much hp like dozens of other things!
These are the same folks that limit the inlet size on turbos (34mm!) or limit the size of radiator openings etc, etc, etc in an effort to reduce power, not because turbos, or cooling, or methanol injection is not viable.
Is it corrosive, sure, just like the salt content on a lot of our cars, so it does become a value judgement in terms of perfomance. Just like how many tires do I want to own/replace in relationship to the amount of traction I desire on the steet or the track aka venue. I'd also like to point out, this is not your Grandpa's meth injection system where a couple of fire hose sized jets are fired off with a big on/off switch.
My injection is controlled by a digital programer triggered by any number of inputs from boost pressure to starting pressure to total pressure etc and is totally adjustable/tuneable.
As far as a cheap add on, really, if you consider that digital system costs slightly more than the average car in this forum, yes that would be true ha, ha, ha. Ask me how I know.

[mattdickmeyer]

WOW!!! Are you looking for a job?? Name your price & I will pay it. I am in need of help at the shop as I am usually scheduled a year out at all times. No really, I am not going too involve myself in a pissing match with you. This right here is one reason I don't come on the forum. The fact is, I am an expert in my field & I am known to be among the top 5 engine builders in the country. There is NOTHING in it for me to give advise to people. I just think that if someones view on a topic is inaccurate, they would appreciate being informed. The fact is, I have actually worn out a dyno in development in my engine program. I guess if you had a 2,000 HP Mitsubishi powered Festiva, the WWII bit would be relevant. Actually, things have been done in the past & present that work & sometimes not so much. I have to be honest with you, the local fire department uses water to extinguish combustion. Yes, I do know that water injection can increase HP especially in high cylinder pressure engines, but there REALLY is a reason why my shop (and my competition) use air to water intercoolers on all our high end engines at the cost of thousands of dollars, when water injection cost hundreds. I guess maybe I'm in over my head on some of this lower powered stuff & that I should just stick with 3,000 HP engines.

[blkfordsedan]

In a case like this I would always give up a little compression to increase air flow through the camber. The small reduction in static compression is nil when considering the increase in (dare I say) volumetric efficiency, offered by the heads increased airflow ability..

Im with you on that. I wouldn't have been as worried if the motor was 300+ CID with 60cc chambers and 9.5:1 CR to start with. But with 1.6L, 37cc chambers and 9:1, even the small amount I took out dropped my static down to 8.8:1. The cam I'm using also closes the intake later, so I was concerned about dynamic compression.