For my slow going turbo project i was thinking of using cnk 8.5:1 pistons, but i don`t have the tools and an install is way to expensive for my budget. Anyways, can using a thicker head gasket actually lower compression? If so will the copper one from kore do the trick, I wish i knew how thick the stock one is. Any other tricks for lowering compression would be great. But leaks are not an option lol

 

Well, Alpine does that.

But it screws up the way the combustion chamber is designed.

So what ends up happening is you will end up running more boost and getting less power out of it.


But it does work.

I think Kore sells some copper gaskets..

 

Read up on "quench" area or "squish" area in combustion chamber/pision design. You really don't want to lower compression via a thicker headgasket. You "can", but going with low compression pistions is the better way to go.

Have you read "Maximum Boost" by Corkey Bell, or "Turbochargers" by Hugh McInnes? You might want to pick up one or both. They both explain the problems of thicker head gaskets and both reccomend against it.

 

"The thought of trying to improve a head gasket should not imply that the head gasket is a weak link. A new stock head gasket, mated to flat surfaces and accompanied by properly torqued head studs, is a good joint. Head gaskets in general do not tend to "blow." Rather, one could say that detonation will blow anything, and the head gasket is often the first thing standing in line. Almost always, the most effective cure for blown head gaskets is control of detonation."
Bell

[ April 21, 2003, 07:20 AM: Message edited by: Aoshi ]

 

random i do have max boost, but i am in the middle of exams so i have only skimmed through it at this point. I will probably get the pistons over the winter, so i guess i will leave it stock untill then. So once i get the turbo in what kinda boost will be safe with stock internals. I heard 15psi, but that sounds a little high. What is everyone running?

 

Stock pistons, rods, headgasket and boost? For a beginning setup, you want to stop at about 5-8psi depending on your choices for intercooling, ignition retard and fueling.

5psi would likely work if you're using a small generic intercooler, stock injectors with a fistfull more fuel pressure (RRFPR + pump) and an MSD DIS2 unit with a good amount of ignition retard.

8psi would work if you're using a better built generic intercooler, slightly larger injectors than stock, S-AFC unit + static fuel pressure and again the MSD unit.

10psi is doable with a good intercooler, 440cc injectors or larger, decent fuel management (SAFC or SAFC2), better pump, ignition timing control, and some luck.

You could try 12psi, but it's likely that the extra boost isn't going to net you much extra horsepower because you've hit the wall on several things. You will need an EXCELLENT intercooler, 440cc injectors + extra fuel pressure, S-AFC to keep it tuned right, probably an S-ITC to keep the ignition timing down while the foot is on the floor, an MSD unit to keep the ignition timing pulled back seperately from the S-AFC tuning, etc etc etc.

How much money do you have? smile.gif

 

I will be getting the cnk ecu for ignition and fuel. Money is limited, but only cuz i don`t want to spend too much on a car that i`m going to sell in 2 years. If i get the ecu, will i still need the msd?

 

Theoretically, from what I know of the CNK computer, you shouldn't need the MSD for it's ignition retard abilities. It may still be a decent idea for just the stronger ignition, but on the stock motor, you won't need it just yet.

With his computer, I would stop at no more than 10psi SO LONG AS you're using a very good intercooler and the bigger fuel injectors. If you aren't going to spend for the bigger injectors and a good IC, then you need to feed it less boost.

High compression and boost is very do-able, but comes at it's own cost. It doesn't make for a good "cheap" project...

 

Ok this is kinda related. i know there are different sizes of turbos. And the bigger the more torque and hp the smaller the the lower but yeilding less lag. Well If you were to compaire a small turbo boosting at 10psi vs a big turbo boosting at 10psi would the worries of Compression ratios be the same? this is assuming everything in the car is the same except the turbo size.

[ April 21, 2003, 02:28 PM: Message edited by: Aoshi ]

 

I wouldn`t call it a cheap project. I just didn`t want to spend the time and money on installing cnk pistons, during the summer in ontario, i would rather my car be out of comission in the winter. I will tell you what i have and what i`m getting.

What i have. Mistu 14b turbo, just rebuild and ported
dms 1g turbo manifold, ported
dms 2g co2 housing, ported
walbro 255 fuel pump
boost controler
What i`m getting
Aem fpr
rc eng 440 or 550 injectors, you tell me.
cnk ecu
gauges, various
fmic, probably used
bov and piping. let me know if im forgeting anything