How much boost is too much?

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OK- I'm getting 30++psi with the wastegate disenabled. I don't know if my gauge stops after it runs out of numbers or if it would keep going around. It is probably inaccurate after it runs out anyway. When I hook the wastegate up it cuts me back to 25psi max, and its hard to get it there. I think I can control my wastegate by crimping the hose to it at different levels so how much is the limit of safety? Thats where I'm gonna get it to limit me to.

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Mine: '93 250 LE 4x4 5spd 4:10 Pwr win/loc/mir,cruise,dual 5" chrome stacks,12cm2 turbo,pyro/boost,diamond plate tool box, CB, 16x10" AR rims, 285/75/16 Bf goodrich, US Gear E-Brake,Fuller Roadranger shifter, PW injectors, K&N. "wirenut_21529" on Yahoo Messenger
Moms:'96 Ford B-Series school bus (5. 9 Cummins!)I'm gonna Bomb it!
Dads:'94 GMC 2500 6. 5L Turbo

 

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Read this one

https://www.turbodieselregister.com/ubb//Forum2/HTML/000619.html

 

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So, this is saying 30+ is okay, right? Rapid temp. change, egt's, and cooldown are where you screw up and stuff breaks???

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Mine: '93 250 LE 4x4 5spd 4:10 Pwr win/loc/mir,cruise,dual 5" chrome stacks,12cm2 turbo,pyro/boost,diamond plate tool box, CB, 16x10" AR rims, 285/75/16 Bf goodrich, US Gear E-Brake,Fuller Roadranger shifter, PW injectors, K&N. "wirenut_21529" on Yahoo Messenger
Moms:'96 Ford B-Series school bus (5. 9 Cummins!)I'm gonna Bomb it!
Dads:'94 GMC 2500 6. 5L Turbo
pictures.

 

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Originally posted by Wirenut:
So, this is saying 30+ is okay, right? Rapid temp. change, egt's, and cooldown are where you screw up and stuff breaks???

Sounds about right to me #ad

I would like to here about your homespun
boost regulator



[This message has been edited by joesoot (edited 09-27-2000). ]

 

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The limiting factors in the system are 1) the compressor end turbine wheel size (HX35),
2) the fueling availible,
3) the restricted size of the hot end exhaust "path" turbine wheel (in your case 12cm2).
You should be able to theoretically increase your fuel to the unuseable point without being able to "overboost" the engine.
The restrictive size of the 12cm hot end will effectively limit the exhausting rate of the cylinders.
This 12cm while allowing for quicker spool-up than say, a 16cm, will bottle neck at a lower boost pressure and produce higher EGT's than the 16cm under the same conditions.
I'm curious... what is the EGT now, with the 12cm2, and the enhanced fueling?

 

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I think I see what your saying about the "bottleneck" thing #ad
It seems like that 12 is creating more boost than it can use and is probably creating higher egt's. Probably? you ask. Well, my new pyro hasn't come in on order yet #ad
Plus the $$$. I will probably have some posting to do on here when I get the pyro.

 

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Oh yeah. You want a pyrometer. You REALLY want a pyro. Try to keep your foot out of it until you get one on.
I'd recommend a pre-turbo installation as that's where the big temps. are.

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'98 Cummins 12v, Big Medicine. Got Diesel.
http://www.ecpe.vt.edu/~dfritz/RIDES/frank_s/classic92.htm

[This message has been edited by old school (edited 09-27-2000). ]

 

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Got the pyrometer all hooked in today. Got some plaesing numbers. I installed it post-turbo for simplicity and because I know with my luck I'd have metal shavings in my turbine if I did it the other way! I think the dual 5" does the trick. How's this sound?:

• constant speeds: 400 deg.
• pullin out goin thru the gears: 600deg.
• tappin into the meat at any speed: 600-700 deg.
• mashin it uphill to pass psd's and gassers it will reach 1000 deg. but I am far ahead and can let off by that time!
• it gets down to 300 deg. pretty fast when it is cooling down. usually less than a minute no matter how hot it is

I think the stacks help guys, what do you think? How do your readings compare?


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Mine: '93 250 LE 4x4 5spd 4:10 Pwr win/loc/mir,cruise,dual 5" chrome stacks,12cm2 turbo,pyro/boost,diamond plate tool box, CB, 16x10" AR rims, 285/75/16 Bf goodrich, US Gear E-Brake,Fuller Roadranger shifter, PW injectors, K&N. "wirenut_21529" on Yahoo Messenger
Moms:'96 Ford B-Series school bus (5. 9 Cummins!)I'm gonna Bomb it!
Dads:'94 GMC 2500 6. 5L Turbo
pictures.

 

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Wirenut, I am assuming this is a truck that is not loaded? (other than the stacks that is) If you can reach 1000 deg unloaded post turbo temperatures you will be in the danger zone if the truck is ever worked as in pulling or carrying a load! Just a caution to keep a eye on the temps when loaded. I have found that the 14cm2 housing works better when converting to the wastegated turbos on the first gens. Simply because of less back pressures and less EGT's. Just watch those gauges!

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Owner: Stabco Repower. '89, CC, SB, 5sp, 3. 54, 16cm2 housing, maxed fuel, KN, Banks exh w/muffler, Horton fan clutch, Autometer liquid filled gauges, Factory tach option, 100% Dyna-Mat, Borgeson steering shaft, Firestone air bags, Chrysler V-twin air comp, 2. 5" lift, Rancho Shocks, Alcoa LTS wheels, BFG 255/85/R16 MTs (33. 3")

 

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Oh, thats flat out HONIN' on it up a very steep hill. I probably won't be doin' too much pulling with my truck anyway.

 

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Hey Wirenut
Thanks for sending me your "trick wastegate" idea that was actually pretty clever and simple. Anything is cool if it works.

 

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Hi Wirenut.

A thousand F post turbo is, depending upon opinion, at or somewhat past redline. I use 900 F as redline and have seen 850F max so far.

I love pulling long grades-I've passed everything I've tried to!

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'93 W350 Club Cab, Bright White, 5 sp. , 132K, Factory Options: LE, 4. 10 Limited Slip, 7600 lb. rear springs, tachometer, front stabilizer bar. Mods: Banks stinger plus, Linex bedliner, 25,000 lb gooseneck ball, 10,000 lb receiver, Tekonsha brake controller, POWER WAGON injectors-WAY faster than stock!.