Need to know turbo idle rpm

diesel_guy86 · **Posted:** Tue Mar 01, 2016 11:35 pm

Im working on a turbo project for our CRD's and the bearing manufacturer needed to know a few things to properly set up the new bearings. One of these is how fast the turbo is spinning when the motor is idling. I have a laser tach but it and my jeep are 670 miles away. So my question is, does ANYONE out there have a laser tach and would be able to have some free time to measure the rpm for me?

I know its kind of a long shot but the end result will be a ball bearing cartridge that will fit our intake and exhaust housings.

flash7210 · **Posted:** Tue Mar 01, 2016 11:40 pm

Damm.

Wish I could help.

t0rquey · **Posted:** Tue Mar 01, 2016 11:42 pm

flash7210 wrote:

Damm.

Wish I could help.

Make that two of us. Color me intrigued.

diesel_guy86 · **Posted:** Tue Mar 01, 2016 11:54 pm

Pics and details will follow i promise, right now its a scramble to get this last puzzle piece in place so i can get the order in. Looking like a 14 week lead time.

These will be the last turbo youll ever buy for the crd.

mass-hole · **Posted:** Thu Mar 03, 2016 10:46 pm

The Coolant temp was somewhere between 190 and 203 since I have a 203 t-stat.

Jeep in Neutral, no a/c on: 24150 rpm

Jeep in Drive, no a/c on: 27620 rpm

flash7210 · **Posted:** Tue Mar 15, 2016 6:28 pm

Any updates?

diesel_guy86 · **Posted:** Tue Mar 15, 2016 8:17 pm

Ive been mostly in discussion with the bearing manufacturer, but i did get my brand new turbine wheel and the dieselsite wicked wheel2 billet compressor wheel. I didnt get any pics of the new wheel next to the old wheel, but heres a shot of it and it installed on the new turbine wheel.

Right now the bearing surfaces of our turbine shafts measure 7.88mm, or 5/16". The bearings i want dont come in sae so its metric only. The first idea was to precision grind the turbine shaft to 7mm and install two 607 bearings but the lubrication design i want comes in size 61800 (10mm i.d.) and bigger. So now a 7.88mm i.d. X 10mm o.d. sleeve or "bushing" will be machined and slipped over the shaft to use the 10mm bearing.
The lube design has precision holes drilled through the outside of the race the feeds oil to the unloaded side of the balls. This injects the oil in and away from the high centrifugal force in the bearing so that it can better distribute and properly oil the bearing. All other turbos just squirt oil at the face of the balls, the oil has to fight the motion of the bearings to penetrate and get into the bearing where its needed.

This is easier to machine but is not the correct way to oil.
The hole in the housing where the bearing will go into will have grooves machined into it for 2 orings to slip in and serves 2 purposes.
1) this will provide dampening for the rotating assembly. Dampening helps with any slight imbalances and will prolong bearing life substantially.
2) the o rings will seal the oil as it transfers from the port in the housing to the oiling groove/holes in the race.

Housing is going to be machined out of 304 stainless for not only corrosion resistance, but because it has poor heat conducting properties. This will help reduce heat soakback after engine shutdown. The back of the housing where the turbine housing bolts on will be machined from a seperate piece of stainless and installed with some sort of heat resistant gasket between it and the center cartridge, also helping heat soakback.

I have a meeting with the machine shop friday to go over everything.

mass-hole · **Posted:** Tue Mar 15, 2016 11:09 pm

3 bars is a dream on mine.

diesel_guy86 · **Posted:** Tue Mar 15, 2016 11:24 pm

3 bar will need to have a new wheel designed, the number of blades and the angle they curve back changes all that. The straighter the vanes the higher pressure but the lower the efficiency. More blades will bring boost in sooner but will choke for air in the higher revs. Vice versa for fewer blades. Ill talk to the machine shop about producing a high pressure (hp) wheel.

flash7210 · **Posted:** Wed Mar 16, 2016 5:42 am

How many pounds of boost is 3 bar?
Do you measure it starting from 0 psi or from atmospheric (14.7 psi)?

Example:
Atmospheric pressure at sea level = 1bar
My boost gauge at sea level, engine not running = 0 psi
Therefore, 1 bar = 0 psi boost
Then...
2 bar = 14.7 psi boost
3 bar = 29.4 psi boost

I believe the stock turbo is capable of 29 psi but the ECU wont allow it to get that high.

diesel_guy86 · **Posted:** Wed Mar 16, 2016 8:23 am

3 bar gauge pressure so 44.1psi of boost. This means the compressor has to have a pressure ratio of: 44.1+14.7/14.7= 4. Our current compressor wheel tops out at just above 3.5 so 4 could be doable with some customizing. The question now is can we get the engine to take that 3 bar of boost without sending the turbo into surge or having it choked? I dont know, but i have a few tricks that could help, but right now all the focus is on bearings.

flash7210 · **Posted:** Wed Mar 16, 2016 1:56 pm

In theory, a 4 bar MAP sensor should work (bosch 0281002576). It should have the same 0-5v signal voltage but on a different scale.
Problem is that the ECU wont know that the scale is different and will think that boost is still in the normal 0-22 psi range. Maybe the scale can be changed in the ECU programming?

Then again, maybe its not a problem.
I have successfully fooled my MAP sensor into allowing boost up to 27 psi.
Using a sensor on a different scale is essentially the same thing.
The tune would have to be adjusted to inject more fuel complementary to the additional boost. Would take a lot of time adjusting to get it just right.

diesel_guy86 · **Posted:** Wed Mar 16, 2016 3:02 pm

Can any admins move the contents of this thread over to my new thread, ball bearing crd turbo?

Need to know turbo idle rpm

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