Exhaust Braking Mod, need your vote

diesel_guy86 · **Posted:** Sat Mar 18, 2017 4:10 pm

So after quite some time ive finally gotten back around to development of my turbos, more on that another time.

Today I dug out the vane assembly found in all the jeep crd turbos. I compared it to some newer ones found in todays modern turbos and im 99.9999% sure Ill be able to retrofit the new vane assembly into our turbos. This new vane assembly is more efficient in how it directs the exhaust flow into the turbine wheel. This not only will DEFINITELY increase spool up, but it will also enable an exhaust braking feature, incredibly handy in towing situations, as well as downhill coasting. You can use it in everyday driving to save on brakes also, this will require a "modified tune" to enable it in the software but that will be free in the DIY tune section.

Anyway, before I get too involved in it I thought I'd create a poll to see what kind of demand there would be, I cant give a price right now, I would guess all said and done it could be $200-$300, maybe less.

These will be vane assemblies to convert your own turbo to the newer vanes. This can be DIY or you could send it to me to have it done, I don't want to get too into details yet, if there isn't any interest then I wont worry about pursuing this any further. I will do it to my own turbo first regardless.

diesel_guy86 · **Posted:** Sat Mar 18, 2017 4:29 pm

*reserved*

diesel_guy86 · **Posted:** Sat Mar 18, 2017 4:30 pm

*reserved*

geordi · **Posted:** Sat Mar 18, 2017 9:50 pm

Could be interesting, will it require a change to the computer, or simple mechanical change?

I would also be concerned with faster spool up possibly also leading to issues with releasing or controlling the speed and a higher top end, which the turbo may not be able to withstand. This is just a worst-case thought though, and may have absolutely zero basis in reality once you get into the process.

diesel_guy86 · **Posted:** Sat Mar 18, 2017 10:55 pm

Hey Jim,

The faster spoolup comes from the vanes being able to close more at idle, once "up on boost" it will be just like they are now. It would take some experimenting, but it may be possible that the vanes could close on "high idle" for faster warm up in the cold months. This is how my dmax works.

The ecm will require a new tune, seems like most have figured out how to do it now. Jay (mass-hole) has already written a tune closing the vanes in the stock turbo. It worked, but because of the geometry of the vanes they couldnt close enough to do much good, other than make a few more pounds of boost.

If you are able to take the turbo off, you'll be capable of installing the vanes. They are in the exhaust housing and that is the only part that will be taken off. This wont affect the balance of the turbo in any way. Once you get the turbo off youll take the exhaust housing off, held on by 6 bolts. When that is off the vane assembly will be right in front of you, 3 torx bolts and the vane assembly is out. Bolt the new one in, unhook the vacuum actuator from the linkage, line everything back up, tighten the 6 bolts down, reinstall with new gasket and crush washer and your done.

mass-hole · **Posted:** Sun Mar 19, 2017 12:55 pm

Here is a post I put up when I first did the engine brake mod on my stock turbo as proof of concept:

Quote:

I wanted to post up some results from an engine brake mod I tested out today. What I did was increase the VNT control maps at 0 injection quantity from 2400 to 4800 rpms. I believe I set them to around 61%(6100), which is kinda low but wanted to ensure I did not overspin the turbo. What this does is partially close the nozzles in the turbine side so that more back pressure is created in the exhaust and it puts drag on the engine helping to slow it down.

The chart below shows me starting in 5th gear at ~70-72 mph and 0% throttle. I then hit the OD off button to force the transmission into 3rd, still at 0% throttle, and let to rpms jump to 2600-2700 rpm. In the chart is the RPM and boost levels from both my base tune and Engine Brake tune. I did offset the engine brake tune slightly so that they were showing the same RPM at the same time.

so the Engine brake tune shows a clear difference in boost once the transmission is shifted to 3rd and the engine is above 2400 rpm, which means that backpressure is higher and the turbo is working harder. Where I live the ambient pressure is about 800 mbar, so the stock tune was making about 140mbar of boost and the engine brake tune was making 700 mbar of boost. I show a section of 5th gear(low RPM) to show that the engine braking does only occur at 2400 rpm and above. You can see that before the downshift the two tunes are generating the same boost. So basically, this should provide an increase in engine braking

Oddly enough, the rpms seem to drop faster on the base tune. I dont know exactly why this is but it could have been as simple as the wind blowing or being on a slightly shallower angle. Ill play with this more when I get some time.

diesel_guy86 · **Posted:** Sat Mar 25, 2017 2:54 pm

Ive been uploading progress to facebook, but not everyone on here, is on facebook, so here we go.

ive spent most of my time available carving out a jig to precisely drill the holes needed to bolt the newer vk vane assembly into our housing. its turned out that it isn't going to take much work at all to put the new vanes in, once I get the jig done. Last night I snapped some pics of the new vanes in our housing and what it is they do that will allow exhaust braking.

ALSO theres pics of the newer 9 bladed turbine wheel that im going to experiment with. this wheel is used in the 3.0l diesels and can properly handle 240-250hp. Even though it has 3 less blades to extract power with, the 9 blades are longer, thinner, and the whole wheel itself is lighter, which im hoping will help it maintain near factory spool up. If one wanted in the future, I could install the larger compressor wheel that will support 250hp. I realize theres few CRD's at this power level, but that's in part because theres no turbo upgrades available.

closed vanes aka exhaust brake mode

fully open vanes

CRD wheel on the left, new more modern 9 blade wheel on the right.

Exhaust Braking Mod, need your vote

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