Engine/Transmission (1994 - 1998) boost question

[shaft]

Friend of mine has a 12v 96 4x4 3500 with the stock turbo on which he put a non-wastegated 14cm housing. When running 70mph with a 4. 10 rear and no load he is making 25-30 lbs of boost. He has a modified stock airbox (extremely religious as in HOLES) and a K&N filter. Has TST plate (largest recommended for an auto)... ... . Trying to give all the info for the question coming up... ... . EGT stays less than 650 (probe is in the elbow coming off the turbo on the exhaust pipe side)



Ok..... Question is how to reduce the boost... ... it cant be good to run that much boost all the time... ... . Should he go with an even larger housing? A 16 or even an 18? Or ?????

 

[rjones]

WOW I have a 96 and when I had the 12 cm housing it was around 10-15lbs @700* pre turbo..... with the 16cm on now I get 5-10lbs @ 600*.....

 

[Peterbilt379CJ]

Remeber something along with all that boost goes the fuel to match it. What a waste of good fuel.



The engine will not be harmed as long as egt's stay within guidelines.



His fuel mileage must be horrible.



Your thermo-couple for egt is in the wrong place. It belongs in the collector before the turbo. You will lose between 100-300 degrees in the turbo meaning it will be cooler on the exit side than on the entry side.



Again, those boost levels will not hurt the engine. These engines are heavy-duty. These engines can be left under full boost under a full load, wide-open throttle for thousands of hours without harm.



When I get the chance I will post some really cool pictures of several diffrent engines including the 6BTA5. 9 under a full load on a test stand with the entire exhaust manifold and turbocharger glowing white-hot. So hot that you can see the turbine side of the wheel through the housing!!!!!!!!!!!!!!!!!

 

[rjones]

Originally posted by Peterbilt379CJ

Remeber something along with all that boost goes the fuel to match it. What a waste of good fuel.



The engine will not be harmed as long as egt's stay within guidelines.



His fuel mileage must be horrible.



Your thermo-couple for egt is in the wrong place. It belongs in the collector before the turbo. You will lose between 100-300 degrees in the turbo meaning it will be cooler on the exit side than on the entry side.



Again, those boost levels will not hurt the engine. These engines are heavy-duty. These engines can be left under full boost under a full load, wide-open throttle for thousands of hours without harm.



When I get the chance I will post some really cool pictures of several diffrent engines including the 6BTA5. 9 under a full load on a test stand with the entire exhaust manifold and turbocharger glowing white-hot. So hot that you can see the turbine side of the wheel through the housing!!!!!!!!!!!!!!!!!

I would like to see that!!!!!!

 

[bmoeller]

Originally posted by rjones

I would like to see that!!!!!!

So would I. :--) That's hot. :--) What's the temp?

 

[Deezul1]

That doesnt sound right at all. Check the boost gauge against another pressure gauge of some sort. Where does the boost pressure line attach at the engine? What boost does he get at full throttle?

 

[Josparkz]

Originally posted by Peterbilt379CJ

Remeber something along with all that boost goes the fuel to match it. What a waste of good fuel.





When I get the chance I will post some really cool pictures of several diffrent engines including the 6BTA5. 9 under a full load on a test stand with the entire exhaust manifold and turbocharger glowing white-hot. So hot that you can see the turbine side of the wheel through the housing!!!!!!!!!!!!!!!!!

I sure would like to see those picture. Cool. Err , I mean HOT