2 replies to this topic

[Jay425]

I need to replace my motor and figured id go with the best but i need to know what the best is.. my end goal is to hit over 500+ hp With turbo, what block can handle this and were would be the best place to get said motor? any info would be great.. and up grade suggestions and what nots more then welcome..

[Dou123]

from everything i have seen you can get a b18b block with a b18c1 dohc vtec head and boost that whle getting a lot of power out of it. I have heard that the non vtec bottom ends hold up better then the vtec for some reason. So youre best bet in my opinion is a B18 non vtec bottom end with a B18c1 cylinder head. Of course thats just the block youre gonna have to get the right aftermarket crank, rods, pistons, rings, as well as the upper end stuff to handle all the boost or naturally aspirated power your wanting to throw at it.

[Gtjetta97]

I will throw some math out there so you can figure things out from now on as far as how big of a motor you need and how much boost and rpm.
There's a formula for figuring this it is....
RPM* CUBIC INCHES* VE (use .9) /3456

This formula will give you your naturally aspirated cubic feet per minute. You can divide cubic feet per minute by 1.5 to estimate horsepower. You can also multiply liters by 61 to get cubic inches.

Now to find out cfm after boost is added and temperature is changed you multiply your NA cfm by how many atmospheres of intake pressure you are running. Find atmospheres or BAR by
(14.7 + Boost) / 14.7

Now your cfm should be much better after you multiplied by the pressure ratio. Last but not least you take into account for temperature change after the intercooler and multiply. If your intake temps are 32 degrees from extreme ice water intercooling multiply your final cfm by 1.1, if intake temps are around 150 after the air-air IC multiply by .9 because you are flowing less do to the air being hot and expanded. These are close estimated numbers to use. And finally divide your cfm by 1.5 to get Horsepower.

Here is an example of a 1.6 L (98 in3) which revs to 8,000 for safe margin and fills the cylinders 90%. It's running 39 psi of boost (3.7 BAR) and has ice water intercoolers.
98*8000*.9/ 3456 = 204 Cfm Naturally aspirated
204cfm* 3.7 BAR (39 boost)= 755cfm
755*1.1(30 deg intake temps +10%)= 830cfm
830cfm / 1.5 = 554 horsepower
Easy enough? And please know what your doing if you are trying to run 40 psi!! It has been done before, 1.8 D series can make 600+ HP on 40 psi. I don't think it had liquid intercooling but you would have to rev past 8000.

Here are examples of a 1.8 and a 2.0
These have supposed intake temps equal to ambient so forget the final cfm change from temperature as you would just multiply by 1 and the answer would stay the same. If you need the temperature ratio find it by using absolute degrees F in this formula. Note absolute degrees F is actually 460+deg F. The formula is
(460+ambient) / (460+ intake temp)

(460+80) = 540
(460+30)= 490
540/ 490 = 1.102 or + 10%.
So 30 degrees F is 10% denser than 80 deg F.

If you are high speed then go for it otherwise just do the following and leave it out. Here is how much boost you would need on a 1.8 and a 2.0 based on .9 VE 8000 RPM and disregarding temperature change.

110* 8000* .9 / 3456 = 229 cfm NA
229 cfm * 3.3 BAR= 755cfm/ 1.5 = 504 HP
So 34 psi @ 8k for a 1.8L to hit 500 HP

122* 8000 * .9 / 3456 = 254 cfm NA
254 cfm * 2.95 BAR= 750cfm/ 1.5 = 500 HP
So 28.5 psi @ 8k for a 2.0L to hit 500 HP

Please be careful!