Engine building questions: high compression , high compression turbo, e85..etc

[MiltonHavoc]

So i was reading these:

https://www.physicsforums.com/threads/high-compression-turbocharged-engines.646362/

http://www.turbobygarrett.com/turbobygarrett/compression_ratio_with_boost

http://www.xcceleration.com/cr-boost%20101.htm

And it got me thinking.
How would you estimate the hp on a build like this.
Running an NA b6d (for a base so we are all on the same page) at a compression ratio of 13:1 or greater on e85.
And what about splitting the duty of raising the compression ratio between the head and the pistons say a 75% increase by pistons and 25% by head work?
I also read that the cam would possibly have to be changed out to compensate as well, so i need to learn about cam profiles.

So by all that I have read, theoretically, this should produce an ingine that is good on low end tq, less chance of detonation, increased chance of pre ignition. But, it should have a good streetable feel to it.

Since it will be taking away from top end, which ill probably never see, a turbo could be used to compensate for that.

So am I pretty solid in my theory?
What have I missed or gotten wrong?

Help me out!!

[bhearts]

You can estimate roughly 4 percent hp for ever point of compression gain. At least that was what Chevy guys got with a 350 in one article I was reading. How that would compare engine to engine, idk.

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[bhearts]

But you don't plan to rev to redline, but you want the turbo there for high rpm power?

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[bhearts]

It sounds like you want a supercharger

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[Advancedynamix]

13:1 b6d would be more expensive to build than a b6t. Trust me. 10:1 comp. Is about the limit for a road going b6d. At 10:1 these engines get the job done pretty well though. I've had several people tell me that mine feels stronger than a bp car after taking it for a spin.
You won't be able to run a turbo and 13:1 compression on a b6d unless your running e85, and even then that's pushing it.
Also, higher compression doesn't hurt top end performance unless your detonating, which you would be on pump gas. The most recent breed of ultra high compression consumer car engines is possible because of high pressure direct injection systems and extremely sensitive engine management systems. The money that it would cost to develop a b6d with these systems could pay for a new Fiesta ST, and insurance for 2 years.

[bhearts]

I think 10:1 sounds healthy too. Then, you can just get good bolt ons to make you all that extra power. E with a turbo car is cool, because in a pinch you can fill with petro and just dog it around for a while. But if you run out of e with a high compression motor. You're stuck.

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[bhearts]

I should have stated, fill with petro and either reflash your programmable aftermarket ecu for gas, or turn down the fuel pressure.

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[Advancedynamix]

Yeah, in order to run 13:1 comp on a b6d, you'd need custom flat top pistons. No use in buying custom standard sized pistons, so you'd have to pay for a bore and hone, and while your at it you may as well replace all the bearings and seals in the engine. All said and done you'll have around 1000 bucks into an engine that won't run on Pump gas. It would rip on C16 though, but that's not cheap. A turbo is much more cost effective.

[MiltonHavoc]

E85
Custom flatop pistons
Yes, sorry, i forgot to mention supporting headwork

Charlie, i dont know if its because it was a newer engine, as they didnt state what engine it was, or what but one of those articles said it was running a 16:1 on e85 with 19° advanced timing.

1k isnt bad considering you'd pay that and then some for an off the shelf turbo kit for most cars.

The drag guys get airplane fuel for 2.75 gal. But i dont know what octane ,as they never say what airport they get it from.

So what about using the cam and a head spacer to help raise compression?

Not arguing what you guys are saying, just trying to get a better grasp

[bhearts]

E85
Custom flatop pistons
Yes, sorry, i forgot to mention supporting headwork

Charlie, i dont know if its because it was a newer engine, as they didnt state what engine it was, or what but one of those articles said it was running a 16:1 on e85 with 19° advanced timing.

1k isnt bad considering you'd pay that and then some for an off the shelf turbo kit for most cars.

The drag guys get airplane fuel for 2.75 gal. But i dont know what octane ,as they never say what airport they get it from.

So what about using the cam and a head spacer to help raise compression?

Not arguing what you guys are saying, just trying to get a better grasp

Unless I don't know what a head spacer is, you need the opposite. A head milling. Which means they take material off the head face.

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[ECCustom]

Is there a supercharger available for a stock 1.3 injected?

[Advancedynamix]

MoltonHavoc
You can put a b6t together for 600 bucks and it will walk all over 1000 dollar high compression b6d and run on pump gas. There is a ram horn turbo manifold on eBay right now for 95 bucks (they do require a little work to fit though) and a used GT2554 can be had for under 250 dollars. bolt that to your b6d with no intercooler and water meth injection (used kits can be had for 200 bucks).
A head spacer isn't going to raise your compression. You will need to have the head milled .025" , and custom made pistons with relocated valve relief pockets and eliminate the dish. If your lucky you'll get the pistons made for 600 bucks (these aren't off the shelf aftermarket pistons, you'll have to have them engineered and custom made). Another 80-100 for the block work (bore and hone to match new pistons). After all that you'll still have an engine that really doesn't run right because you've now altered the combustion chamber in a way that isn't optimal. These engines were carefully designed by mazda to be turbocharged, and they work very well with a turbocharger. They don't work very well as a high compression N/A engine.
You'll need to do some more research on actual Mazda engines if you want a more thorough explanation. Tear a few down, spend years working with them, race them, break them. Thats the best way to learn.

[Advancedynamix]

Is there a supercharger available for a stock 1.3 injected?

Yes. There are several options. Nothing directly bolts on though. You'll need to make some brackets and pulleys and charge pipes. 110hp should be pretty easy to get.

[jdobbs86]

I say go for it, don't let common sense and a wealth of wisdom bring you down. You can pick up 10.6:1 pistons with rings from 949 racing for 539.00 which really isn't that bad. They are supertech so they might be crap but who knows or cares.
Start there with boost and meth...
If you get real bored and decide to spend a bunch more money and would like to see something blow up... check your valve clearances then shave until you make contact... set your cam timing accordingly...and begin praying.

I mean if a tiny little company like Mazda can figure out how to run 14:1 (and they plan on going higher) every day in their skyactive mobiles...why not us?

[blake4591]

I'm not a B series expert but as far as I know the upper limits for compression on them is in the 11:1 area and that requires 93 octane and very careful timing maps to make good power. I personally would not want to build a motor that requires e85 due to its somewhat random availability. It also gets weird around this time of the year as every batch seems to be different mix do to the anti-icing additives that we get in the midwest. I've run E85 in my 2.3 turbo at various times over the last two years and it is fun to play with especially with turbo motors but you really need to have an ECU that you can tune (I use the mega/mircosquirt) and generally know what you're doing.

General when talking about compression in N/A engines you want to run as much as possible until the fuel becomes unstable. More compression makes the engine more efficient, more efficiency means more torque and more torque means more horsepower. The only problem is that the higher cylinder pressure and heat means more NOx. This matters if you're going to have to pass any type of emission testing as it's very easy to exceed the EPA limits just ask Volkswagen.

If you want to continue on the 1.6 build I would recommend that you pick up some ZM-DE heads to use. They bolt on the B6D blocks and have some significant port and combustion camber improvements. I would guess that one of these heads worked over with 11:1 compression and a good tune could make around 120 ft-lbs and 160 hp to the wheels. This would put you into the range of the average b6t swap and well ahead of a BP.