Thread: Isuzu Turbo Manifold

Yes he cut his and turned it over.
its been called an Army manifold but just looked in a manual I have and it shows the low side angled one.
I have just bought a T28 modified (wastegate hole welded up) and it bolts straight up to this manifold (high mount one) but it looks as if its going to touch the bonnet or be very close.
Other threads use the low angle one.

Didiman

I have a GT28 with this manifold. The compressor does sit fairly close. The outside bonnet skin can get warm but not enough to be hot to touch. Pic below.

Thanks. Good pic. It looks as if you have the water cooling hooked up. Other threads say not to bother. Where did you tap into.?
Did you have an install thread somewhere?

Def-90 also has the top-mount manifold, but I think the IHI version (slightly different pattern and divided outlet) with a Super CT26 on top.

I run a T25/T28 hybrid with the water cooling not connected. IMO it's only needed on petrol engines.

I think water cooling is good for keeping turbo temps more constant ie less extreme temp range. It gets supply by tapping into a gallery on the driver side of the motor. It drains to the thermo top housing. The engineer who fitted the turbo wanted to ensure water continued to circulate by heat siphoning.

Originally Posted by rar110

I think water cooling is good for keeping turbo temps more constant ie less extreme temp range. It gets supply by tapping into a gallery on the driver side of the motor. It drains to the thermo top housing. The engineer who fitted the turbo wanted to ensure water continued to circulate by heat siphoning.

dougal,justin and blknight did explain a few points in one of my threads as to the problems with water cooling etc etc but i am still trying to figure out how to get the system working properly as i can see there concerns but i would also like the cooling hooked up like yours as it is there i would like to use it....so many things to do

Originally Posted by rar110

I think water cooling is good for keeping turbo temps more constant ie less extreme temp range. It gets supply by tapping into a gallery on the driver side of the motor. It drains to the thermo top housing. The engineer who fitted the turbo wanted to ensure water continued to circulate by heat siphoning.

Yes heat siphoning on cool-down is the only reason it exists. On a petrol idle-down doesn't cool the turbo very well as exhaust flow volume drops right down (throttled engine) and the temperature doesn't drop that much.

On a diesel on idle down we get the full engines capacity every 2 turns and the temps drop right back (I get 170C warm idle). The only time I have to idle down is parking at the top of hills (skifields, mountainbiking etc). Even slowing to a stop from 100km/h the EGT's are cool enough to shut down straight away.
My engine came with the IHI turbo (not water jacketed), I've been running garretts since about 2005 without the water cooling hooked up and haven't had a related problem yet.

Originally Posted by Dougal

Yes heat siphoning on cool-down is the only reason it exists. On a petrol idle-down doesn't cool the turbo very well as exhaust flow volume drops right down (throttled engine) and the temperature doesn't drop that much.

On a diesel on idle down we get the full engines capacity every 2 turns and the temps drop right back (I get 170C warm idle). The only time I have to idle down is parking at the top of hills (skifields, mountainbiking etc). Even slowing to a stop from 100km/h the EGT's are cool enough to shut down straight away.
My engine came with the IHI turbo (not water jacketed), I've been running garretts since about 2005 without the water cooling hooked up and haven't had a related problem yet.

Likewise, I make sure my EGTs are <200 and ideally ~140oC (warm idle on mine) before shutdown.