Low Boost

[Archive]

I just had the 16 cm2 turbo housing installed (by Cummins Southwest) along with the pyro and boost gauges. The trouble is that even at high freeway speeds (all-out), the boost gauge only reads 8-10 psi. Does this sound right? From what all of you have been writing, I should be seeing higher numbers. The truck runs fine but I'm not sure if it should or could be running better. I've inspected the intake system (rubber boots, pipes) for cracks and holes and all looks good.
What do you guys think?
Thanks for any and all help. The TDR is the best resource on the Web.
Steve Marley,
ABQ, NM

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'93 W250 CC, 4X4, 3. 54 Gearing, Factory Stock Except For:
16cm2 Turbo Housing, Pacbrake, Amsoil Bumper To Bumper w/bypass,
Boost/Pyro/Oil Temp Gauges, Hella Lights.
NV4500 5sp, Icom 2 Meter and Uniden CB Radios

 

[Archive]

Smarley: It appears low. First confirm the new casting has 16cm cast on the side of it. Then carefully trace all hose and pipe connections on the pressure side (you probably did). Check your boost gage tubing for leaks and kinks (even at the back of the gage).
Check the air filter condition.
Check your exhaust for restrictions.
And finally the fuel filter. Fuel again makes boost, possibly the pump is not putting out the optimal rate, or the total fuel delivery. After checking all the above, Pump throttle break - over, and full opening should be verified, along with pump timing.
Check and record your boost through each gear, up a grade, with a load,(if possible, or against a headwind) and your max. EGT.
What were your boost readings with the previous housing?
Hope this helps.

 

[Archive]

I had two problems with my truck that contributed to my truck not running at it's optimum. My truck had a pinched exhaust pipe at the very top of the bend where it goes over the rear axle. This could not be seen from underneath. The muffler shop found it while replacing the muffler. Next, check to make sure the throttle is opening all the way when the pedel is floored. The Floor mat etc. could be in the way and in my case the cable was just adjusted too long.

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92W250, 4X4, 3" Trail Master suspension, Gas Shocks, Extended Cab,3 Gauge Ispro pod, 16cm exhaust housing, Flow Master muffler, Turned up pump, Performance Friction Carbon Metallic pads, Corex shoes.

 

[Archive]

Old School, I purchased a 16cm2 housing from TST two weeks ago and when I received it,it had the number 21D9 cast on the side of it. I e-mailed TST questioning if they had sent me the right housing and they replyed that they only sell 16cm housing and the number on the casting was just a part number. However it did have the number 16 stamped inside one of the intake ports that attach to the exhaust manifold. I mentioned that it seemed silly to have a 21D9 stamped on a 16cm housing that was supposed to replace a 21cm housing.
Walt

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91 D350, BD Brake,Gear Vendors O/U Drive,Gauges-Pyro,boost,tach,trans,rearend,brake,
Airbag rear,Transfer flow tool/tank, Exh. sys,Rino lined bed, Alcoa Mags,SS runningboards.
16cm.

 

[Archive]

walmor: A genuine Holset hot end housing has "HOLSET 21" (if it's a 21cm2) cast into the outside spiral. The location once mounted is on the left, or toward the rear of the truck, near the four nut flange. I'm not aware of any stamped numbers, although there are the caster's tooling and run I. D. 's cast into the outside also.
Compare the old 21 housing with the new one. The new 16 should look smaller even from the outside.
Regards.

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'92 CUMMINS/DODGE 5SPD, 4WD 16cm2 turbo, mod. pump and injectors, max. flow exhaust, K&N... .
S. T. O. K. E. D. ... . accept no substitutions
www.turbodieselregister.com/memberimages/r0300343.jpg
www.turbodieselregister.com/memberimages/r0300341.jpg

[This message has been edited by old school (edited 01-24-2000). ]

 

[Archive]

Old School, The numbers on the housing are not stamped they are cast (raised) and they are in the location that you mentioned. I did place the old housing on top of the new housing and did not notice much of a difference. It does however give me more boost and smoother operation, but nothing "Earth Shattering". If I didn't have a boost gauge I wouldn't be able to tell it was better than what I had originally.
Walt

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91 D350, BD Brake,Gear Vendors O/U Drive,Gauges-Pyro,boost,tach,trans,rearend,brake,
Airbag rear,Transfer flow tool/tank, Exh. sys,Rino lined bed, Alcoa Mags,SS runningboards.
16cm.

 

[Archive]

Old School, one more thing that I forgot to mention was, there was a 21 (stamped) inside the intake port of my old housing exactly where ther is a 16 stamped on my new one.
Walt

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91 D350, BD Brake,Gear Vendors O/U Drive,Gauges-Pyro,boost,tach,trans,rearend,brake,
Airbag rear,Transfer flow tool/tank, Exh. sys,Rino lined bed, Alcoa Mags,SS runningboards.
16cm.