measureing turbo pressure- how to ....

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measureing turbo pressure- how to ....

Postby jethro » Fri Jun 24, 2016 7:33 pm

Found a new-surplus air pressure gauge (1-18 psi).
Took out the manifold air temp sensor ( I had a plug there actually) and put in a pipe to compression fitting.
Ran about 8 feet of 1/4 inch polyethylene tubing from the fitting in the top of the intake cover. As a test- I just ran the tubing and gauge into the cab through the door crack. When I start up and test here is what I see.
very slight dip below zero at idle. bring RPM up to 12-1500 RPM - I see barely 1 psi. Basically no pressure it would appear.

Is there some "problem" attempting to sense the pressure at the top of the intake cover plate ? ( I wouldn't think so-
would think that volume would have to be under positive pressure normally-- )

Tomorrow I will leak test my 1/4 inch tubing connections-----
If that looks OK- ...... I might take the turbo output pipe off and rig up 10 PSI compressed shop air input to it with
the other end at the intake blocked off. Since the motor wont be running--- if I have a leaking coupler hose or if the
ford intercooler has holes --- I should be able to hear it------

Should I try the same test with the BHAF filter off ?

I am running the stock H1C turbo (stock turbo injectors) and a full size BHAF intake filter, Ford intercooler-

Am I missing anything really obvious (and stupid- :jocolor: here ??????

Tim
Last edited by jethro on Sat Jun 25, 2016 7:40 pm, edited 1 time in total.
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Re: measureing turbo pressure- how to ....

Postby DMan1198 » Fri Jun 24, 2016 7:40 pm

If you were just free revving the engine in park/neutral it doesn't load the engine, so no boost is ever built. It also won't build full boost in the low gears
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Re: measureing turbo pressure- how to ....

Postby stuffy » Fri Jun 24, 2016 9:15 pm

What he said. You will never see boost in neutral at 1200. Drive it and see what it does then
92 w250
Silver Bullet, pump maxed, full manual 47re, 5x18s, Hungry Diesel piston pump
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Re: measureing turbo pressure- how to ....

Postby jethro » Fri Jun 24, 2016 9:41 pm

OK - will try that tomorrow---

This must be because the pump is only running at minimum under no load- if little fuel then little exhaust flow volume ?
Not used to diesels running on governor where the fuel can change without RPM changing.....

So I should see the boost in like 4-th and 5-th gears at 45-60 mph and medium-low rpm ?????
I havnt even gotten it up fast enough to even get into 6-th gear :mrgreen:

So maybe I should go ahead and feed the tubing through the firewall and make a temporary spot for the gauge.....
(am going to mount it above rear view mirror in a sheet aluminum box.- once I see its working )

Thanks- will test tomorrow for effect !
T
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Re: measureing turbo pressure- how to ....

Postby stuffy » Sat Jun 25, 2016 4:39 am

You should be able to see some boost in the lower gears. Just max in the higher ones
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Re: measureing turbo pressure- how to ....

Postby DodgeFreak » Sat Jun 25, 2016 8:21 am

Mine will build 10-15 psi at 2000-2500ish.
92 D350 Cab and Chassis. Auto stock, wiring gremlins. 330k miles
92 W250 Ext cab rotted completely out. Auto, pump maxed, 215 ppump nozzles, Denny T2 pin.
85 D350 single wheel, converted to cummins, getrag, turned up 2 turns and afc screw flush.
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Re: measureing turbo pressure- how to ....

Postby spencerdiesel » Sat Jun 25, 2016 6:06 pm

What they all said :D Though both high revs & high load will push the snail the hardest, high boost is much more dependent on load ,once enough revs are attained to spool that is.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
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Re: measureing turbo pressure- how to ....

Postby jethro » Sat Jun 25, 2016 7:39 pm

tried it tonight ---
Didn't see much boost in the 1-st or 2-nd ----- a little in 3-rd (like 1-2 psi)
in 4-th and 5-th I could see a little if I let the RPM's get low and then tromp on it a little--- then all I saw was about 4 to5---
and about 6 at maximum.... Never saw it higher than 6 - and it was only at 6 for an instant....
I could only see about 3 or 4 for any length of time (2 to 4 sec until the rpm's came up (and the road speed) up to
the next shift point ...

Does that seem like enough ???? should I do the leak test with shop air ? I was expecting about twice the boos that I saw
on this test..... but I have no basis of experience to go on ..........

Tim
(it actually moves fairly good for a 9000 lb truck..... about the same pickup as my old f-150 with the gas in-line 6 cyl)
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Re: measureing turbo pressure- how to ....

Postby DMan1198 » Sat Jun 25, 2016 10:08 pm

I would say your gauge doesn't seem to be reading correctly. If you were really only getting 2-4psi it'd be a smoky, gutless mess. You're much more likely to be in the teens, or twenties with how you mention it running.
Ducati- professional nap taker, and thread derailer extraordinaire
Brownie: 80 dodge heavy half. Ghost cummins under the hood, and some sinister plans
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Jaeger: 12 ram 3500. Lifted, exhausted, and fed an excessive quantity of air
The Huntress: 02 Jetta TDI. No muffler, egr, horsepower
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Re: measureing turbo pressure- how to ....

Postby CumminsPower59 » Sun Jun 26, 2016 6:33 pm

That or you haven't put your darn foot into it and get a decent reading on what it's doing.
Ike

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Re: measureing turbo pressure- how to ....

Postby DMan1198 » Sun Jun 26, 2016 10:23 pm

There is that. When we mention how much boost we can make we are talking about full load, full throttle. For my truck with a pretty small secondaried set of compounds I can't make 8-10psi in 3rd by 50km/h, on the highway at 70mph in 5th I cruise at 8psi flat, and up to 18psi hitting hills. My maximum boost is 50psi overall, and 25 out of my primary.
Ducati- professional nap taker, and thread derailer extraordinaire
Brownie: 80 dodge heavy half. Ghost cummins under the hood, and some sinister plans
The Roo Hunter: 93 w250, lifted, 2 whistle machines, and a bunch of other go fast goodies, uhh..... not there yet
Jaeger: 12 ram 3500. Lifted, exhausted, and fed an excessive quantity of air
The Huntress: 02 Jetta TDI. No muffler, egr, horsepower
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Re: measureing turbo pressure- how to ....

Postby Remps » Mon Jun 27, 2016 8:22 am

As was mentioned, you need to bury your foot in the carpet. It takes 16-18 psi to make the rated 160 flywheel hp, so bury your foot in the high gear from 50-65 mph and check your boost. Only way to find out where you are at for fueling.
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'96 2500 S/C L/B,2wd,NV5600,3.54 L/S,cai,egt,pacbrake,mbrp exhaust,10 plate.
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Re: measureing turbo pressure- how to ....

Postby jethro » Fri Jul 01, 2016 10:24 pm

Yeah- I think that's exactly the thing that's going on-----
I have built this thing with good gas mileage in mind- and being easy on the motor.
I noticed I can ooze along at 50-55 mph in 5-th gear and maybe 1200 rpm (don't have my tach working yet)
it is flatland here......
I am building a little sheet aluminum console for my gauges- so my gauge is on my desk at the moment.
Will try the "bury the pedal" thing once its back on. :-)
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