Plans for boost - Which head is better for....
11-21-2004, 03:09 PM
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Plans for boost - Which head is better for....
I own a 92 Civic HB Si which has an engine code of D16Z6. My cylinder head is pretty messed up so I found a good deal on a Y8 cylinder head. I'm pretty much sure it will fit right onto my block but my question is....
What is the differance between a Z6 head and a Y8 head? This head came off of a '97 civic. Would the Y8 cylinder head be better than the Z6?
My future plans are to build a cylinder head and boost it. I got a good deal on a complete turbo kit as well, so I just want to make sure im doing things right the first time by getting the best head for this application. Thanks for the help.
What is the differance between a Z6 head and a Y8 head? This head came off of a '97 civic. Would the Y8 cylinder head be better than the Z6?
My future plans are to build a cylinder head and boost it. I got a good deal on a complete turbo kit as well, so I just want to make sure im doing things right the first time by getting the best head for this application. Thanks for the help.
11-21-2004, 04:30 PM
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Re: Plans for boost - Which head is better for.... (crzyfool24)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crzyfool24 »</TD></TR><TR><TD CLASS="quote">I own a 92 Civic HB Si which has an engine code of D16Z6. My cylinder head is pretty messed up so I found a good deal on a Y8 cylinder head. I'm pretty much sure it will fit right onto my block but my question is....
What is the differance between a Z6 head and a Y8 head? This head came off of a '97 civic. Would the Y8 cylinder head be better than the Z6?
My future plans are to build a cylinder head and boost it. I got a good deal on a complete turbo kit as well, so I just want to make sure im doing things right the first time by getting the best head for this application. Thanks for the help. </TD></TR></TABLE>
The differences between the Z6 and the Y8 are combustion chamber design and port design. The Y8 head will raise compression on a stock block as I believe the stock combustion chamber is about 3-4cc's smaller than the Z6.
What is the differance between a Z6 head and a Y8 head? This head came off of a '97 civic. Would the Y8 cylinder head be better than the Z6?
My future plans are to build a cylinder head and boost it. I got a good deal on a complete turbo kit as well, so I just want to make sure im doing things right the first time by getting the best head for this application. Thanks for the help.
</TD></TR></TABLE>The differences between the Z6 and the Y8 are combustion chamber design and port design. The Y8 head will raise compression on a stock block as I believe the stock combustion chamber is about 3-4cc's smaller than the Z6.
11-21-2004, 06:32 PM
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Re: Plans for boost - Which head is better for.... (dr_latino999)
So if the Y8 has higher compression, should I just stay with the Z6? I heard that if you want to go turbo....You would want to have lower compression...Right? 
11-21-2004, 06:37 PM
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Re: Plans for boost - Which head is better for.... (crzyfool24)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crzyfool24 »</TD></TR><TR><TD CLASS="quote">So if the Y8 has higher compression, should I just stay with the Z6? I heard that if you want to go turbo....You would want to have lower compression...Right? </TD></TR></TABLE>
It depends on what kind of driving you'll be doing.
https://honda-tech.com/zero...age=1
Tony took a GSR block and ran 11.5:1 Arias pistons with ITBs, boosting 12 PSI. Tony's setup probably works well on a road course. If you want to drag race, you'll probably want to lower compression to handle more boost.
Edit: Then again... this probably has nothing to do with the subject at hand. *slaps self*
</TD></TR></TABLE>It depends on what kind of driving you'll be doing.
https://honda-tech.com/zero...age=1
Tony took a GSR block and ran 11.5:1 Arias pistons with ITBs, boosting 12 PSI. Tony's setup probably works well on a road course. If you want to drag race, you'll probably want to lower compression to handle more boost.
Edit: Then again... this probably has nothing to do with the subject at hand. *slaps self*
11-21-2004, 06:44 PM
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Re: Plans for boost - Which head is better for.... (crzyfool24)
You are better off with the stock head for turbo, and yes lower compression is better for turbo applications.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by http://www.sdsefi.com »</TD></TR><TR><TD CLASS="quote">Turbocharged Engines for the Street
Turbos are a different ball of wax but many of the same mistakes are made when modifying them. Most of the same power increasing methods from above can also be applied to turbo engines. Because turbo engines usually have lower compression ratios than atmo engines, they do not take kindly to hot cams on the street. The gain in top end will almost always be offset by a huge loss in the lower powerband and more turbo lag. Stock cams are the way to go on most turbo street engines. Don't waste your money on so called "turbo cams" for 4 and 6 cylinder engines. These may boost economy slightly but they almost always lose power. Most of these were designed by guesswork rather than by actual turbo experience. 4 Valve engines in general when turbocharged do not need hotter cams for the street.
Porting a turbo head will make the same type of gains as on an atmo head despite what some people say. You can make the same power with less boost or more power with the same boost.
To obtain higher than stock outputs, the compression ratio should be LOWERED on a street turbo. This will permit higher boost with optimized timing on low octane fuel. Forged pistons are an excellent idea on turbos as they have 2-3 times the strength and heat dissipation of cast pistons. Forged connecting rods, colder spark plugs and stronger head gaskets are also recommended.
Stock turbos are usually sized for mid range torque and are undersized even for stock top end power. Compressor and turbine size upgrades are needed to realize substantial power gains. Going too large on turbos will lead to poor low end response. Turbos need to be properly matched for the application and primary intended usage. A couple of rules of thumb can be used if you have access to a compressor map. HP X 1.62 = airflow in CFM, HP divided by 8.07 = airflow in lbs./min. Avoid matching for efficiencies of under 65% at full power and operation near the surge line also.
Intercooling is extremely important. Stock intercoolers with a few exceptions are total crap when used for performance applications.They offer low efficiencies and high pressure drop. Install a properly matched core from Spearco. The closer that your charge temperature is to the ambient temperature, the higher the HP potential will be.
Finally, boost pressures can be raised to increase engine airflow and power. This can only be done within the limitations of the fuel octane rating and ignition timing. Read the other tech articles relating to combustion and fuel for a better understanding. In any case, running 20 psi on the street is relatively meaningless. High boost pressure does not necessarily mean high HP. If you are running this kind of boost on the street, you probably have a host of mismatched or restrictive parts on your engine. With properly matched components and an efficient intercooler, one rarely needs to exceed 15 psi on the street. With these in place, you will be at the safe mechanical limits of most stock based engines and HP will be doubled or tripled over stock. Check out some of the cars on our project page prepared at Racetech if you don't believe this. Since engine life will plummet once you exceed this type of output, it is not a viable option for most people to be rebuilding an engine every 10,000 miles. You don't have a streetable engine in my opinion at this point.</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by http://www.sdsefi.com »</TD></TR><TR><TD CLASS="quote">Turbocharged Engines for the Street
Turbos are a different ball of wax but many of the same mistakes are made when modifying them. Most of the same power increasing methods from above can also be applied to turbo engines. Because turbo engines usually have lower compression ratios than atmo engines, they do not take kindly to hot cams on the street. The gain in top end will almost always be offset by a huge loss in the lower powerband and more turbo lag. Stock cams are the way to go on most turbo street engines. Don't waste your money on so called "turbo cams" for 4 and 6 cylinder engines. These may boost economy slightly but they almost always lose power. Most of these were designed by guesswork rather than by actual turbo experience. 4 Valve engines in general when turbocharged do not need hotter cams for the street.
Porting a turbo head will make the same type of gains as on an atmo head despite what some people say. You can make the same power with less boost or more power with the same boost.
To obtain higher than stock outputs, the compression ratio should be LOWERED on a street turbo. This will permit higher boost with optimized timing on low octane fuel. Forged pistons are an excellent idea on turbos as they have 2-3 times the strength and heat dissipation of cast pistons. Forged connecting rods, colder spark plugs and stronger head gaskets are also recommended.
Stock turbos are usually sized for mid range torque and are undersized even for stock top end power. Compressor and turbine size upgrades are needed to realize substantial power gains. Going too large on turbos will lead to poor low end response. Turbos need to be properly matched for the application and primary intended usage. A couple of rules of thumb can be used if you have access to a compressor map. HP X 1.62 = airflow in CFM, HP divided by 8.07 = airflow in lbs./min. Avoid matching for efficiencies of under 65% at full power and operation near the surge line also.
Intercooling is extremely important. Stock intercoolers with a few exceptions are total crap when used for performance applications.They offer low efficiencies and high pressure drop. Install a properly matched core from Spearco. The closer that your charge temperature is to the ambient temperature, the higher the HP potential will be.
Finally, boost pressures can be raised to increase engine airflow and power. This can only be done within the limitations of the fuel octane rating and ignition timing. Read the other tech articles relating to combustion and fuel for a better understanding. In any case, running 20 psi on the street is relatively meaningless. High boost pressure does not necessarily mean high HP. If you are running this kind of boost on the street, you probably have a host of mismatched or restrictive parts on your engine. With properly matched components and an efficient intercooler, one rarely needs to exceed 15 psi on the street. With these in place, you will be at the safe mechanical limits of most stock based engines and HP will be doubled or tripled over stock. Check out some of the cars on our project page prepared at Racetech if you don't believe this. Since engine life will plummet once you exceed this type of output, it is not a viable option for most people to be rebuilding an engine every 10,000 miles. You don't have a streetable engine in my opinion at this point.</TD></TR></TABLE>
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