Thread: VE 4CW crankshaft max load

My SR16 was 8cw no girdle.

They run the girdle because the 8cw cran is heaveir and throws far more stress onto the bearings.

Nick M needs to go back to engineering school and stop being a sheep.


You guys are just not listening and or being open against your own "theories".

4cw doesnt need the girdle as its far less stress on the bottom end. The 4cw came with a low rev limits for 2 reasons.
1) the camshafts in the lowport motors were designed for low range efficiency. Fuel economy and emission standards.
2)The 4 cw came in engines attacked to automatic trasnmissions(4wd and vans). An automatic transmission doesnt provide the torque stress that a manual direct drive transmission will. There is no intial torque load up on the crank or block because of this.

Cosworth porduces a 4cw crank - they must be stupid too. Nissan motorsport ran a 4cw crank in the N1 racing engines - they must be stupid too.

I have pages upon pages of refute and evidence to support there is nothing wrong with a 4cw crank. All you guys can come up with is that Mr Miko says this, and Andreas all you come up with is that nissan changed the design and tomei run an 8cw.

Tomei run 8cw because their cranks are designed for strokers and extremely high load. Their cranks are also lighter by default of their material and their counterweight design also means their 8cw crank is just as light as a 4cw. They are also designed to be run with a girlde (which we all know robs power). Their cranks arent made to push for every single last N/A hp - they are perceived to be put behind big boost.

shorter stroke. Less load ont he block but more load on the rods.

u said it.. RACING ENGINES.

Yehp more stress and load than any street car? Whats the point.

nissan also disassembled those motors after each race, replaced bearings as needed and had an entire crew of mechanics on the payroll


Comparing a race team to a street car driver?

Not in the N1 category class which is what they raced in. They had to run the car with ****logated parts and parts available off the shelf.

my 2 cents on this...

Using a 4cw crank for years (50,000km)at very high loads ,street races "high speed" , track daily use etc...( over 400-600+whp) and high speed use (my favorite ejejeje)( 8500+ rpm races) I have found 0 issues with the 4cw crank, in fact Im still using it in my new build , I have never try a 8cw ...and never done a extencive study 4cw vs 8cw.
cheers.

you statement doesn't discount anything i said. they still could replace bearings after races even with nismo ones

Ah this is going round in circles again.
There is ALSO pages and pages of engineering papers on the subject proving that 4cw cranks DO have a harmonic. My statement had nothing to do with what miko said however I agreed with what he said how he came to that conclusion doesn't bother me. I made my mind up indepentantly from the research I did.
Clearly no one will change your mind so i'll call this arguement moot

So to the original poster, if you can make sense of any of this arguing just make up your own mind, i'd recommend reading some engineering papers on the subject, SAE is a good place to start. But a pretty good assumption is more revs = more stress how much you decide to over engineer it is up to you.