Disconnecting wastegate rod from wastegate

[tom chelbana]

Wanting to up performance on step grades and thinking of disconnecting wastegate rod from wastegate on turbo. Have a 500 HP ISM 04 Essex and on a previous C 8.3 pickup 10 psi boost from 20 to 30 psi and alot of power and even a little MPG and wondering if I can do that with this ISM with variable pitch turbo. Getting around 30 to 32 psi on hills but sometimes it jumps up to 40 or alittle higher. When to boost goes up we get 5 or more miles increase in speed on step grades.

[rvrepairnut]

Originally Posted by tom chelbana

Wanting to up performance on step grades and thinking of disconnecting wastegate rod from wastegate on turbo. Have a 500 HP ISM 04 Essex and on a previous C 8.3 pickup 10 psi boost from 20 to 30 psi and alot of power and even a little MPG and wondering if I can do that with this ISM with variable pitch turbo. Getting around 30 to 32 psi on hills but sometimes it jumps up to 40 or alittle higher. When to boost goes up we get 5 or more miles increase in speed on step grades.

A 500HP ISM should have hoards of power? I have owned a few 8.3 cummins and were always 30Lbs boost stock? my current ISL gets 34-36 lbs stock
U can pinch off the vacum line and increase boost but you takes your chances over burning a piston

[Pelledan]

If your turbo is indeed variable geometry there probably is no waste gate as the VGT technology regulates turbine speed/boost instead of the waste gate. A wastegated turbo has that feature so as not to overspeed the turbo or overboost the engine. Boost pressure is directly related to cylinder pressure. Typical diesel design limitations restricts cylinder pressure (the force applied to downward piston movement at the time of fuel/air mixture detonation) to around 2300-2600 PSI. Exceeding that would apply above design limit stresses to the wrist pins, connecting rods/bearings and crankshaft main bearings. Trust me, you would be playing with fire. Besides, 500 HP (1200 ft lbs?) should quench the power thrist of just about anyone.

Dan

[neilking]

The rod is what keeps my waste gate closed.

[Steve Ownby]

Originally Posted by Pelledan

If your turbo is indeed variable geometry there probably is no waste gate as the VGT technology regulates turbine speed/boost instead of the waste gate. A wastegated turbo has that feature so as not to overspeed the turbo or overboost the engine. Boost pressure is directly related to cylinder pressure. Typical diesel design limitations restricts cylinder pressure (the force applied to downward piston movement at the time of fuel/air mixture detonation) to around 2300-2600 PSI. Exceeding that would apply above design limit stresses to the wrist pins, connecting rods/bearings and crankshaft main bearings. Trust me, you would be playing with fire. Besides, 500 HP (1200 ft lbs?) should quench the power thrist of just about anyone.

Dan

Dan is exactly right. When the ISM went to the CM870 ECM the fuel system included a VG turbo which has no waste gate and an EGR to meet the EPA requirements of '04.

[rvrepairnut]

Originally Posted by neilking

The rod is what keeps my waste gate closed.

it opens and closes your wastegate

[neilking]

I know it opens and closes. Without the rod it will just flop open with nothing to close it.

[palehorse89]

When I had my turbo off the wastgate valve was frozen shut do to soot and lack of opening. I have no boost guage in my coach so I got it loosened up so it would work and never noticed any performance differance or anything for that matter. It might be frozen in place again as this is very common to do this the cummins garage said.

[rvrepairnut]

Originally Posted by palehorse89

When I had my turbo off the wastgate valve was frozen shut do to soot and lack of opening. I have no boost guage in my coach so I got it loosened up so it would work and never noticed any performance differance or anything for that matter. It might be frozen in place again as this is very common to do this the cummins garage said.

Iam not a turbo expert but i doubt your wastegate was frozen unless I guess u drove the thing at 1/2 throttle its whole life and never maxed out the turbo pressure(boost) which in my world of things would be almost impossible ? but if u did well I guess u did(drove it at 1./2 throttle its whole life)

[palehorse89]

Originally Posted by rvrepairnut

Iam not a turbo expert but i doubt your wastegate was frozen unless I guess u drove the thing at 1/2 throttle its whole life and never maxed out the turbo pressure(boost) which in my world of things would be almost impossible ? but if u did well I guess u did(drove it at 1./2 throttle its whole life)

No I have not run my coach at 1/2 throttle most of its life, I am usally running right down the road with it, like I stated and I don't know why I took the turbo off to do some manifold work and when cleaning up the turbo I unhooked the linkage and the wastegate valve was frozen up in place, penatrating oil and some time and I worked it loose. This is not a story, it is what happened.

[rvrepairnut]

Originally Posted by palehorse89

No I have not run my coach at 1/2 throttle most of its life, I am usally running right down the road with it, like I stated and I don't know why I took the turbo off to do some manifold work and when cleaning up the turbo I unhooked the linkage and the wastegate valve was frozen up in place, penatrating oil and some time and I worked it loose. This is not a story, it is what happened.

like i said it,s obviously possible its just unusuall that one could be that lite footed driving a diesel pusher.I have and do own diesel pusher and have never seen one powerfiull enough where you were,nt constantly running turbo to max and causing waste gate to open.thats all I was trying to say
its extremly unlikely

[dennis45]

Originally Posted by rvrepairnut

like i said it,s obviously possible its just unusuall that one could be that lite footed driving a diesel pusher.I have and do own diesel pusher and have never seen one powerfiull enough where you were,nt constantly running turbo to max and causing waste gate to open.thats all I was trying to say
its extremly unlikely

Are you sure it was not the Exhaust Brake that was siezed? That is pretty common.

[rvrepairnut]

Originally Posted by dennis45

Are you sure it was not the Exhaust Brake that was siezed? That is pretty common.

funny thing u should ask as I too wondered but Iam sure anyone that is adept enough to actually remove a turbo from a cummins would have to know the difference so i never gave a second thought till your post

[dennis45]

Originally Posted by rvrepairnut

funny thing u should ask as I too wondered but Iam sure anyone that is adept enough to actually remove a turbo from a cummins would have to know the difference so i never gave a second thought till your post