Jake Performance

[Rawze]

BTW: That 570 with its waste-gated turbo is actually weaker than just about anything newer (engines with electronic turbo's) on the jake brakes.


The reason why the newer red engines have a stronger jake is in fact the VGT electronic turbo + the jake design of the enigne vs. other engines.

Red engines literally have the strongest jake brakes in their class, and the red engine maker used to advertise this a lot, years ago.

and .. NO, there is no fuel being applied, so NO, there is no 'injection timing' or any other type of firing of the cylinder involved, etc.


What is different about the red engines is that it uses the electronic turbocharger to choke the exhaust manifold to block off up to 90% of the exhaust flow. After it does this, what it does next is the part that is unique to cummins ... even on the old 570, although it is not as good at it due having no VG turbo ...

So ... It traps and compresses the air in the cylinder(s) like any other engine does to make extra resistance to the fly-wheel ... but it does something different before releasing it out the stacks.

When that compressed air is released finally into the exhaust manifold, the red engines traps a big portion of it there (using the turbo itself to choke the manifold), and opens a second exhaust valve to transfer it into a second cylinder .... and then compress it again, amplifying the amount of air into that second cylinder quite a bit above what normally would have been able to be taken in via the intake alone.

It is a pretty unique trait to cummins engines.


By the way .. rear end ratio plays a big role in how strong the jake is on an engine too. The higher the ratio, the stronger the jake is... Ie >> a set of 4.11's will be quite a bit stronger in holding power than a set or 3.27's. This is yet another reason that these newer heavy haul trucks need to be geared right instead of some garbage, engine killing, fleet-spec' tall rear ends.



-=== related to engine brakes on newer engines, since we are on the topic ... ===-

This double-compression engine brake design can also be a huge problem if someone has a bad-delete program shoved into their ecm. More than 90%+ of all delete programs are bad.. and about 40% of those, some completely clueless moron who made that program also fumbled around with the jake brake settings "in attempts to make them stronger". This is a massive no-no.

On newer trucks with VG turbo's, It is almost always those guys who have abnormally tall rear ends vs. the loads they carry, that complain about the jake feeling 'weak' from the factory. Because of this, many of these so-called 'tuning' idiots are quick to try to make up for it in the programming out of sheer stupidity.

By choking the exhaust/turbo harder than it is programmed/intended for (usually editing the turbo engine brake maps in the programming), then that highly compressed air will cause extra exhaust valve closing delay when the valve does open. This sets the engine up to easily allow for a piston strike a valve at higher rpm ranges and the engine brake on max. This destroys the engine very quickly, and I have seen this done to them many times over the years + the aftermath.