Curtas

Random,
Is the alpine spacer an oversized gasket, or does it need a gasket in addition to it? Or does it need a gasket on each side?

I did some turbo calcs and if I even want to run 6 psi on the kit, I'm going to have to lower the compression to prevent detonation. That still with 94 octane fuel.

So if I'm using the spacer, I just wanted to know what extra I'd need to do the install.

Also, I looked into the procedure for doing a head removal. Not too bad, but looks like it'll take a long time. Anyone here do this before? Is it a PITA? What's with the special tool the manual lists for head-bolt removal?

Thanks,
a

Red

The aftermarket gasket is usually just a thicker replacement for the stock gasket... It uses a thicker metal layer in the center, which sets the head another few tenths of a millimeter away from the block deck.

Look here: http://www.fxtreme.org/Ultimate/NonCGI/For...TML/000060.html

Thicker head gaskets are a bad thing.

In any case, removing the head takes about four or five hours if you've got all the tools and are ready to rock. The "special tool" is an allen wrench on a socket so you can apply crazy torque to the head bolts. The bolts have hex-shaped indentions in the top, and this is where you use a fat allan wrench to take them off. There are two sizes of allan you'll need -- there are two sizes of headbolts to remove (coincidence - nope!)

I suggest against the head gasket...

-Red-

Curtas

How do you get around the problem of high-boost, high-compression == detonation with pump gas. I've read on methanol and water injection -- don't particularly care for either.

All the equations I've found (and that calculator on the site bry referenced) suggest mad octane (100+) for a 10.0 compression ratio and 10 psi of boost. I'll rework the math to check for errors.

Also, I got the McInnes Turbocharger book for $9 coming. It was a closeout and it was the last copy. Still looking for a deal on the Corky Bell book.

Thanks Red,
a

Random

Onpol manages with 10 PSI and stock compression.

Amazon.com has the Corky bell book for $24 and change. I got it there awhile ago, and they still have it listed on their site.

[ July 25, 2001: Message edited by: Random ]

Red

Heya Curtas,

I know it sounds odd when you have all these online calculators and import places telling you it will never work; it really does though.

Here's something I want you to think about: static compression is a measure of the space that's in a cylinder when the piston is fully down, compared to the space that's in the same cylinder when the piston is fully up. Our motors are rated at 10.3:1 static compression, which means all the air and fuel your motor breathes in will be compressed by better than 90% before it's ignited.

Ok, that's static compression.

The problem is that, depending on the layout of your car, you will never compress the air and fuel by 90% or more before the spark plug fires. Here is where we get dynamic compression.

There are certain limiting factors, such as blockages in the intake system and valve timing that keep the motor from getting a "full breath" of air -- especially at high RPM's. Because it cannot completely fill the cylinder with air to begin with, the dynamic compression is actually much lower than the static compression.

Dynamic compression changes with engine RPM, air temperature, air density and with engine modifications. This is how you're able to get more power (in naturally-aspirated format) out of the same motor without swapping pistons... Your static compression is the same, but your dynamic compression is changing because the engine is actually able to get a bit more air into the cylinder on the intake side.

So here's the deal...

Running four, seven, or even ten pounds of boost seems to work just fine on the stock motor. Chris Highet's supercharged Tib has been running for a few years; granted he blew a ring land, but that was because his MF2 fuel controller went to crap and he ran severely lean while in 3rd gear with the car floored at 5000+ RPM's. Oops.

Detonation in most cars is caused not by high compression, but by hot spots in the motor. This can either be caused by high intake temperatures (read: get a good intercooler) or can be caused by fuel not atomizing correctly. The intercooler is easy, the fuel atomization isn't...

Fuel atomization is a term that describes how well the gasoline mixes with the air. If you have huge fat droplets of gasoline, it will burn very slowly, and it will also stick to things. A prime example would be hot spots on your pistons -- you're burning a big fat gasoline droplet on top of your piston, and it burns really hot and really slowly. That little part of your piston will become very hot itself, and on the next power stroke, that hot spot can contribute to pre-igniting the fuel mixture. Bad bad bad...

You want the gasoline to be in a very fine mist, so that the air and fuel mixture is very even without any fat droplets to screw stuff up. Keeping the mixture like this will help IMMENSELY to keep detonation out.

One thing that you can do with high compression that you cannot do with low comprsesion is to "squish" the air and fuel around, allowing it to atomize better. When the piston comes up to the top of the cylinder, it can come VERY close to the cylinder head, and thus move the air around very turbulently and get that gas/air mixture really thick. Where these two parts (piston and cylinder head) meet is called a quench area; quench areas serve as almost "mechanical octane" because they help that fuel stay atomized and thus reduce the chances of detonation or preignition from hot spots.

Remember, the entire project I'm doing is entirely based on high compression and ridiculous boost. It's been done for years on Hondas, so it's time we start doing it on other cars. If you want to run more than about 8-10psi, you'll need to start seriously considering other alternatives (example: my head and pistons are being completely reworked for my project) but I wouldn't automatically just aim only for low compression.

Low compression motors suffer from slower spool times, lesser thermal efficiency, less fuel economy, and less performance when off-boost. Typically, most low compression motors are also quenchless, so you can still get a nasty case of detonation on "weenie boost" if the fuel system isn't right.

If you're still really concerned about detonation, just go buy an MSD DIS2 unit with the optional boost retard module. I think Onpol is using one of those for his 10psi monster, and it's working fine for him. I will likely be using one as well.

-Red-

Random

Red-

You would not need the MSD unit if you go with a HalTec or Motec setup, correct?

Also, check out MSD's webpage. They have a fully programmable DIS box now. You can hook it up to a laptop, and play...

Red

You wouldn't need an MSD unit, but it's generally a good idea if you're going for serious power. I know Libra's rally Tiburon uses the stock system, but an MSD just gives you that extra "umph" to get all that extra fuel and air burned just that much better. You just wouldn't need the optional MSD components like boost retard or nitrous retard, because the Haltech/Motec would take care of that for you.

As for fully programmable MSD's: cool stuff, but yet another bandaid fix If you've got an aftermarket standalone computer system, the programmable MSD would be useless.

-Red-

Curtas

Wow, Red! Thanks for the input. I'm leaning away from the Alpine kit. The custom piping and "everything included" aspect is really nice, but I'm having doubts about the spacer and definitely about the 5th injector. Escpecially since you refer to both with the ™ : Bad Thing.

Onpol said he'd help me out with a custom set, but his method will end up costing more which I don't have right now. Plus I need to start learning my way around the vacuum, oil, and water hoses more before I ever start tapping into them.

I may just postpone the turbo until next summer or later. I'll keep doing research, upgrade the fuel system first, get a better exhaust on and keep doing homework.

I hate being patient, but all this research has taught me one thing . . . you don't want to do this project half assed!

Thanks for all the input guys.

A

Random

Curtas

The alpine kit is a great starter. Oil lubed/water cooled turbo, manifold and Unichip plus other sundries for $1900.

You can choose to NOT use the Spacer, and NOT use the 5th injector....or use them for awhile...then replace them with "Good Thing" ™ components as you get the $$$ flow!

Curtas

Damnit Random wink.gif I have my mind set on waiting and you have to talk me back into it. smile.gif

I'm selling an amp on e-bay and should be getting a refund check for some speakers that never arrived (factory problems). All told, that will be about $1300, so I could probably swing the kit. Of course, if either falls through, then I definitely won't have the money and may just get some N/A mods for now (headers and exhaust) and save for a while.

Ah, decisions, decisions. smile.gif

thanks for the input. BTW, how's yours running? Any news on that bad ground wire?

a