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tree98 · 01-21-2022, **(Subject: ISX 2350 485 )**

I think it's been Said that sometimes these engines have been known to over boost right from the factory and turbo tables need adjustment to correct it.

Rawze · 01-21-2022, **(Subject: ISX 2350 485 )**

(01-21-2022 )Hermjeji Wrote: CM2350, ISX15 550, 2015

Boost pressure measured several times, EGR tuneup completed, goes up to 38PSI. ECM was flashed with latest calibration a few years ago. This is from the factory sensor and not a secondary boost gauge. The truck is due for DPF bake and de-ash. However, i was looking at some data I collected a while ago when the truck was pulling some short 5-10% grades loaded in the city, what is the max turbo speed supposed to be? This one is getting above 100,000 RPM.

Also - did the overhead set a few weeks ago, same results afterwards. No axial turbo play, impellers looked good on the intake side.

first of all, that pic you posted makes no sense compared to your statement. --- looks exactly like someone stomping the accelerator in short bursts and then letting off it?. Are those seconds or minutes at the bottom of the chart? There is also unexplained data in it. - What little data can be read also is not that unusual for a non-deleted truck.

NEXT: The CM2350 max RPM rating of the turbo is 145KRPM mechanically, with a 120k settings for protection limits. 100k is below this, so I don't know what your trying to say.. H#ell... most Vg turbo will get to 80K even when doing a parked regen cycle. ... so if your concerned about the turbo spinning well within its operating limits.. then your worrying about zero nothing.

As far as the boost pressures on a CM2350 ... it is quite normal for the intake to get to 36,.. 38 psi when there is EGR gas present and the truck is not deleted. This is because about 4-5 psi (or more) of that IS EGR GAS PRESSURE that is coming back around into the intake, bypassing the turbo, and artificially inflating the intake pressures vs. what the turbo alone is providing. Again.. its absolutely normal.

Hermjeji · 01-21-2022, **(Subject: ISX 2350 485 )**

City driving is what this is from, probably a left turn cruising to a red light and then starting up the hill if I remember. This guy is a bit heavy footed too.

My question is whether the turbo tables need to be remapped, as tree said above. Because if they do, I need to start getting in touch with the right people. The other ISX CM2350 sits below 34 PSI, and the X15 CM2350 stays below 32 ish PSI.

Just got curious about the turbo speed.

Rawze · 01-22-2022, **(Subject: ISX 2350 485 )**

(01-21-2022 )Hermjeji Wrote: City driving is what this is from, probably a left turn cruising to a red light and then starting up the hill if I remember. This guy is a bit heavy footed too.

My question is whether the turbo tables need to be remapped, as tree said above. Because if they do, I need to start getting in touch with the right people. The other ISX CM2350 sits below 34 PSI, and the X15 CM2350 stays below 32 ish PSI.

Just got curious about the turbo speed.

IS THIS TRUCK DE-MANDATED? ... IF NOT, AND ALL THE EMISSIONS ARE STILL ACTIVE .. THEN YOUR STATEMENTS ABOUT BOOST ARE INCORRECT!. IT NEEDS TO BE LEFT ALONE!. I have seen at least 100+ times where some model cm2350 trucks will get to 38 psi boost, when all the emissions systems are in tact.They ran just fine. - It all depends on what tier, that CPL, what engine modes it happens to be running in, and a lot of other factors.

Just make sure the turbo is the right part# for that tier engine. Then also make sure the program is the one that belongs in that engine/truck... and that it matches the engine serial number according to quickserv.

you mentioned doing an EGR tune-up.. This implies that thing is NOT de-mandated.

================

HOWEVER...

IF IT IS DE-MANDATED.. THEN YOU NEED TO GET THE WHOLE PROGRAM LOOKED AT TO ENSURE IT IS CORRECT.. Because I do not know of anyone who is worth their salt at all that would let a CM2350 get as high at 38 psi boost AFTER a delete has been done. That much boost after a de-mandate is absolutely harmful, as there is no more EGR gas or combustion control to handle it. On a DELETED/DE-MANDATED CM2350, it is not uncommon to see it that high, because no opne made any corrections. Without egr gas, etc. this will cause the engine a severely shortened life.

Figure out what you are referring to... is it de-mandated or not?.

Maybe the 2 scenarios have gotten confused in your head somehow?. otherwise you question is not making much sense to me.

Hermjeji · 01-22-2022, **(Subject: ISX 2350 485 )**

(01-22-2022 )Rawze Wrote: ...
Maybe the 2 scenarios have gotten confused in your head somehow?. otherwise you question is not making much sense to me.

It is mandated. I have gotten confused by the previous posts. Thanks for clarifying in detail Rawze.

amermextrucker · 01-22-2022, **(Subject: ISX 2350 485 )**

Lately my boost on my engine has gotten as high as 33psi. Boost also goes up really fast, I dont have a lead foot . Im having alot of trouble keeping it under 15 psi last 2 weeks. Its been really windy here in Illinois lately maybe that might be issue? MPG is at 5.2.

Truck is demandated by a forum member. Engine is a CM2350 , CPL 3937, 450hp , 1750 torque . Also no CEL, but havent connected insite yet.

Ive owned truck 22 mos now , just ran overhead ( 2nd time ) 1 month ago. Air filter is going on 6 mos. Changed out IMAP & Exhaust back pressure sensor at time of purchase (egr tune up) are they due to be changed out again ? TIA.