Gees, don't use imperial calculations.
Metric is so much easier to use and makes much more sense.
Budget CA18DET build!
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...
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
P.S, the golden number using KW and NM is 9549, which makes it impracticle to use in calculations...
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.
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
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.
@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 😉
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 .
Ok lets just live and let live.
😉
Guys, guys, guys, lets just agree that CA's suck and SR's rule! 😛
Sokar wrote:
Guys, guys, guys, lets just agree that CA's suck and SR's rule! 😛
HEHE ditto!!
Says the one who drives the silly wobbling engine 😂 .
wankelwankelwankelwankelwankelwankerwankelwankelwakelwankel
😂 😂 😂
Man I go away for a few meetings and when I get back my thread is on page 3, with not even 1 picture yet.
Now, I appreciate everyone's input and your points are taken, but please let's leave the mega hi-jacks for another thread.
Reason I ask is because I often read through people's article threads, and it's very annoying to sit through 30 pages of posts, where only 10 of those are actually about the project. I'm sure you've all been there.
So if you wanna discuss the merits or lack thereof of something in great detail, maybe start another thread and post the link over here?
Sweeeeeet!!
ps: Will post at least 1 pic up tonight!
Doc G, Thumbs up for the CA, I'm busy with mine at the moment as well.
A burst waterpipe killed it, but any longer and the sludge and crap blocking the oil pickup would have done the same.
Yeah Doc I would seriously consider trying to clean out the water and oil paths in the block.
Okay after a lot of long & hard thinking regarding my goals for the car, and consideration of all the factors I could think of, and also after quitre a few lenghty forum discussions, it is unfortunate but looks like the ca18det build is not going to happen. 🙁
I was looking forward to it, but such is life...
Keep an eye out though- I'll be launching a new project veeeeeeerrrrrrrrrryyyyy shorlty 😉
So what are you going to run??
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