Budget CA18DET build!

Gary57 · Post by **Gary57** » Tue Oct 21, 2008 11:06 am

This is going to be a good article, good luck man. Keep us posted.

HancoB · Post by **HancoB** » Tue Oct 21, 2008 11:48 am

Gary57 wrote:This is going to be a good article, good luck man. Keep us posted.

Ditto

Can't wait to see!

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Tue Oct 21, 2008 12:08 pm

I’m running Aries Pistons pasted 10K long time ago no smoke, No compression drop not using oil but dripping it damn crank seal, I though you weren’t ,listening to cousin's uncle's sister's son

You are effectively doubling your power output on stock internal’s it’s your call your money your motor. You are doubling the pressure on the top of the piston you are also doubling the force on piston rings and landing like I said. Now with added MLS Headgasket and ARP Studs the only give will be with the piston themselves, your tune will need to be spot on and nothing less then 550CC injectors, I would also recommend a FPR and an upgraded Fuel-pump if you don’t have those already.

The definition of BMEP is: the average (mean) pressure which, if imposed on the pistons uniformly from the top to the bottom of each power stroke, would produce the measured (brake) power output.

Stock CA18DET
---------------------------------

HP = TORQUE x RPM ÷ 5252
TORQUE = HP x 5252 ÷ RPM

HP – 129 KW to 173HP

TORQUE =173x5252÷7200

Torque = 126 Lb-ft.

Modified CA18DET
-------------------------------

HP = TORQUE x RPM ÷ 5252
TORQUE = HP x 5252 ÷ RPM

HP – 250 KW to 335HP

TORQUE =335x5252÷7200

Torque = 245 Lb-ft.

Now the BMEP
---------------------------------

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)

CI - 1809cc – 110 Ci

Stock CA18DET
--------------------
BMEP = 172

Modified CA18DET
--------------------
BMEP = 336

Gary57 · Post by **Gary57** » Tue Oct 21, 2008 12:14 pm

Pink those calsulations are based on the fact that the motor make peak power at peak torque, these 2 are hardly ever near each other.

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Tue Oct 21, 2008 12:28 pm

LOL Agreed the pressures get much higher as torque is put into the correct RPM range but it still remains double and that’s the point I’m making

You can get the equations and work it out for yourself

You are doubling the load on that piston

Stock CA18DET
---------------------------------

HP = TORQUE x RPM ÷ 5252
TORQUE = HP x 5252 ÷ RPM

HP – 129 KW to 173HP

TORQUE =173x5252÷5500

Torque = 165 Lb-ft.

Modified CA18DET
-------------------------------

HP = TORQUE x RPM ÷ 5252
TORQUE = HP x 5252 ÷ RPM

HP – 250 KW to 335HP

TORQUE =335x5252÷5500

Torque = 319 Lb-ft.

Now the BMEP
---------------------------------

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)

CI - 1809cc – 110 Ci

Stock CA18DET
--------------------
BMEP = 226

Modified CA18DET
--------------------
BMEP = 438

Guy · Post by **Guy** » Tue Oct 21, 2008 12:35 pm

Gees, don't use imperial calculations.

Metric is so much easier to use and makes much more sense.

Sokar · Post by **Sokar** » Tue Oct 21, 2008 12:51 pm

Guy wrote:Gees, don't use imperial calculations.

Metric is so much easier to use and makes much more sense.

The "golden" rpm 5252 is based on HP and ftLBS, I think there is a kw/nm equivalent...

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Tue Oct 21, 2008 1:02 pm

OK let the IT guy clean this UP

kW x 1200
BMEP = ---------------
litres x rpm

129KW X 1200
-------------------
1.8 x 7200

= 154860
---------------
12960

= 11.9 BAR

11.9 Bar = 172 PSI

In bar or PSi it still doubles the pressure

Sokar · Post by **Sokar** » Tue Oct 21, 2008 1:03 pm

P.S, the golden number using KW and NM is 9549, which makes it impracticle to use in calculations...

http://en.wikipedia.org/wiki/Dynamometer

HancoB · Post by **HancoB** » Tue Oct 21, 2008 1:04 pm

Copy and paste is just so easy...

The thing is anyone can copy and paste calculations.

Prove them, test them yourself and then you know.
For his mods stock might be fine.(its personal choice)

Get first hand experience before doing something that might cost you a lot of money.

Also remember this. 1 strong component in a environment consisting of not so strong components will make the other components break.

The Nissan engineers designed our engines to perform at its best within a certain set of parameters and strength factors, they have done their calculations with the materials involved and worked according to the stress, strength and strain factors of those materials.

Once you come and change the strength of one component the equations of the rest are also changed, but you do not take that in to consideration. Thus first get the correct calculations of the stock engine and then see how you can modify it and what else you will need to change for the engine to be at equal and optimum strength.

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Tue Oct 21, 2008 1:25 pm

HancoB Not to be a dick but then prove me wrong. I am up to learn things I mean I read a lot of literature,buy a lot of books so your Input will be welcome and I will roll with the punches

If you have the solution that proves otherwise then prove it to me, I mean I remember having the same argument about metal fatigue with Draco a few months ago involving the stock Turbo compressor wheel failing due to over spinning (Sorry Draco just using that example to make a point) and I finally got documented proof that this will happen why do I always have to double triple prove my point its not illogical to think you will be doubling the pressure on those pistons, Its not Illogical to think it might be nearing the end of it intended operation range I’m sure Nissan didnt intend for the pistons or more importantly the rings and ring lands to see those power levels

But hay I have shown you the calculation used to get the BMEP of the motors these are used by car manufactures the world over I have proved the pressures will double I don’t think it’s a Good Idea to push the stock pistons to this point and I have been open about it, Now You guys can take this info and do what you want with it my point has been made.

Also get you facts straight , I pulled most of this calculations from “Maximum Boost’ its covered in the first chapter because this pressure is what makes the power

Gary57 · Post by **Gary57** » Tue Oct 21, 2008 1:29 pm

Hehe I love it when guys try shorten equations so you have to do less math to get the answer

. If you use the full equation it will make a lot more sense.

But yes I agree with PFB, to double the output you are doubling the pressure on the piston. As I said if you were to constantly run at these pressures the motor will no doubt die, I am sure Nissan never used a safety facture of more than 2

.

A chain is only as strong as its weakest link. If you run a stock HG that is the weakest point, far cheaper to replace than replacing pistons or a whole engine.

HancoB · Post by **HancoB** » Tue Oct 21, 2008 1:55 pm

@PFB hey mate relax. I didn't take you on or say that you are wrong.

What I'm trying to say is that like Gary said, it will only be as strong as the weakest part in the engine, you can't go upgrading your pistons and then just running high boost, the HG will go. Things like that which you have to take in to consideration too.

You will have to look at the wider spectrum. Thats why I used the Nissan engineers to prove the point that they did all their calculations with the given power pressure levels and directly proportional to the metals stress strain and strength levels.

Take a simple example, you cant go fitting a HUGE turbo on a 1.4i golf, the engine was designed to handle a certain stress level. Now replacing the pistons will mean that the poor 1.4i golf HG will blow, then replacing that will mean that the conrods will fail after a while, and then replacing that means that the bearings will fail after that and then replacing that means that the crank will fail, and so it goes on and on and on.

Increasing the strength of one thing technically decreases the strength of another.

If you have to draw a schematic drawing you will see that for every + there will be a -

That is just basic laws of physics.

Thus my point is, don't just say, hey pistons will do that and that and that and its better and not taking in consideration that there are other parts that needs upgrading too.

Take all the factors into consideration. Thats just how I have been told and taught by plenty of a engineering book and lecturers.

just my 2 cc

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Tue Oct 21, 2008 2:10 pm

Dude HancoB…

I’m going to bite my tongue and grind my teeth but if you look at DR G set-up the weak point is his pistons the only place for give will be his pistons but anyway I’m done with forcing my point plus I’m screwing up DR G build thread with a mega highjack. I have said what I have to say that’s that its up to DR G or the club to look further into it or not .

HancoB · Post by **HancoB** » Tue Oct 21, 2008 2:24 pm

Ok lets just live and let live.