DRKSol

can anyone please tell me what kind of power they have heard a d16z6 makes without a turbo. i have a greddy turbo but i wanted to do some mods internal. can you give me some numbers?

96 SOHC VTEC

Search and you shall find your answer.

COMplex.

when you build a motor for NA you build for High compression.

when you build a motor for FI you go for lower compression.

if you already have a turbo, you should concentrate on building the motor to make it stronger and lower the compression ratio.

if you plan to go NA, you're not going to build it up the same way ya know what i mean?

if you build the motor for boost, it's going to be slow if its not actually being boosted on because it will be lower compression.

xXx Justin xXx

ok. i have a z6 /turbo going in tomorrow when my tranny gets here. but anyway... why do people always lower compression for FI? i mean. i understand not making it more compression..... but sleeve it, get some strong *** rods and head gasket. whatever else goes a long with it. and boost it. i can see the side where being able to run more boost is good for mid to high rpms depending on turbo size... but if u lower the compression... you are loosing N/A power for that wonderful 1k-3k daily driving range. and when you lower the CR and run more boost, you increase the lag time correct? i just always thought it to be stupid to lower the compression from 9:4 or 9:1. whatever it is stock.. down to 8:2 or something, just so you can run like 3psi more? just my veiw on that part of it.

but yes.... tring to build the engine to make a lot of power before going FI is going to be hard. you would get more power building it as if you were not going turbo... but then it wouldnt be safe or run properly boosted.

Ricey McRicerton

Im with you SOHC beast....Never could figure out why people would drop CR for turbo. Id just run lower boost on a higher CR, but oh well...

xXx Justin xXx

yea, thats what seem logical to me... keep all the stock N/A power. have more power to pull those low rpms until the lag is done and you start boosting...means more power boosted...when the turbo dies off at higher rpms (those of us that suffer from a stock greddy turbo from the sohc kit) you have more N/A power to pull you to that redline so when you shift you are still at a high enough rpm that you dont have to go back thorugh that lag process all over again. whatever... someday people will learn.

nema741

I'll try and explain why you lower your compression ratio on a turbo'd motor as compared to a NA motor. What does a turbo do? It FORCES air into the cylinders to create it's power. If you lower your compression you can force MORE air into the motor. Meaning you will gain more power with the additional air flow. A stock motor uses approximatly 14.7 lbs of air when it's running. When you apply boost to the motor it allows the motor to use more then 14.7 lbs of air, Now if you are packing more 8psi into the motor that would give you approximatly 22.7lbs of air that the motor is running on. So if the motor only takes 14.7 to produce the "stock" 130hp and you are pushing approximatly 1/2 of the air that it requires normally(14.7) to run you are gaining roughly 1/2 the hp the engine makes on it's own(65hp is 1/2 of 130). So now you would be at around 195 HP. (These figures are all hypothetical. Just trying to explain it some, well.. the 14.7 is a real number)

With all that said. If now you lower your compression so your engine can handle MORE boost you just increase the power output of the engine.

So if you take a NA motor which is High compression. It cannot handle very much boost without overstressing something and blowing the motor. Make any sense? So why not find the happy medium in between the two? Why? If you can make more power from a motor by packing extra air into the cylinders then why would you want to sacrifice that and have a motor that can only handle low amounts of boost but yet isn't built with high enough compression to make it get up and go? ...
Well.. gave ya my explanation of it.. hopefully you'll understand. if not i'll try my hardest to explain it better.