Boost numbers on a 1HDT (5 Viewers)

[onefsatchevy]

Hey Guys,

Just got a boost gauge installed and want to check the numbers....

The truck is basically stock (motor wise) with just over 240 000 Kms on it. The only mods are a Pyro, and a "power" metering rod in the fuel pump.

mild acceleration peaks at around 7psi

moderate and hard acceleration peaks at 10psi

It has not exceed 10psi in the couple of days I have had it on.

Cruising at 50 Km/h 0psi
Cruising at 80 Km/h 2psi

Haven't been on the highway yet, so I don't have a reading for anything higher.

Do these look right?????

Also, I am thinking about adding a manual boost controller to get me a few more psi, and a bit more hp (and for $70 to $100, it appears to be cheep hp)... Don't worry I'm not trying to make it a drag truck, but a bit more passing power would really be nice! That and the "power" metering rod claims that it will work much better with more boost.

So the question is, what is the stock turbo capable of? I was thinking just a couple more psi like 13 or 14 would be a huge improvement without killing the turbo. What is the life span of the average turbo? Seeing how I'm pushing 250 000 km's am I nearing the end of it's life span? I did check the shaft for play about 20,000 km's ago and everything seemed fine, no more than a couple thousandths play.

Anyone out there running a controller????

Thanks again,

James

 

[boogie74]

Hi Buddy,

I don't have a 1HDT. I've got a 13BT but those numbers of yours seem pretty good. Mine had stock boost
of 8psi and I up'd it to 12/13psi. Goes much better. Not sure what the 1HDT is capable of.

A Boost Controller is the way to go. I have a turbosmart. Cut the vac line to the wastgate and put it on there.
Start of with the controller set to zero boost. Got for a drive/stop and give it a half turn. Repeat till you get to 12psi.
I set mine with a bit of headroom so I can increase the boost if I want more power.

Cheers

 

[sandcruiser]

your boost numbers sound about right for stock, maybe a hair on the low side-- I see 12psi if I really push it up a hill, but cruising at 80kph it only makes 2-4 psi.

Some folks have pushed up to 14 or higher without any apparent problems. Search hd-t turbo psi, I"ll bet there is some info out there.

 

[Tapage]

Impress me a bit those low boost numbers are 80km/h .. stock tires .. I thought I push a little more at that speed .. ( well mine aren't stock at all )

 

[onefsatchevy]

I'm running 33's at the moment, so that may explain the low numbers at 80.... And after a bit more time, it won't crack 10 psi, but I haven't done a hill climb yet....

Thanks for the advice guys, hope to pick up a controller in the next week or two...

 

[boogie74]

Good stuff mate.

240000k - your engine has just been broken in
Should have heaps of life left in it. I wouldn't get to crazy with the boost tho.

 

[Adam B]

Sounds about right. Mine was maxing out at 10.5 from the factory but I didn't usually see that in the city, only on the highway.

I have my $5 home-made MBC set to pop at about 14psi although it seems to allow +/- 0.5psi so the absolute highest it hits is still less than 15psi. Any higher and the amber turbo light keeps flickering on and off, which becomes annoying to the eye after a while.

That last couple of psi has a noticable effect on my EGTs and really cleans up the smoke. Of course that means I had too much fuel in the first place but now I think I can add more.

With the wastegate actuator hose disconnected (or the MBC installed backwards ) I have absolutely no trouble reaching 18psi in the city. I just didn't have the heart to let it go higher and keep in mind that was just a few times while testing and getting things setup the way I wanted them.



Having an intercooler helps.

 

[mudgudgeon]

those numbers look a little low. From memory, factory settings should see a peak around 11.5-13psi, the overboost warning light (amber) comes on at 14psi and I think fuel delivery is restricted.
you will see peak boost when the engine is under load, full throttle, such as a long hill in 3rd gear, full throttle. Should peak around 2200rpm.

I found the limit of mine recently, I had no wastegate, fuel turned up, it was peaking at 22psi and was like this for about 12mnths. It was running at 15psi (just below overboost warning on my truck), its fairly widely accepted that the factory turbo is safe up to 15psi, and mine ran well like this for a couple of years.

The turbo on mine disintegrated a couple of weeks ago at 22psi. I am now rebuilding the engine. At around 200k km it looks new, bearings are all in good condition, bores stil have hone marks in them, very happy to see it looking so good. I know of these engines doing over 500 000km with out any problems.

adding a boost controller is easy to do and gives you good adjustment on the boost. More boost alone is unlikely to give any real increase in power, unless the engine is already being overfueled.
you should see lower exhaust gas temperatures with a bit more boost (if fuel settings are left the same)

 

[Adam B]

So what exactly went wrong with the turbo?

Do you have an intercooler?

 

[mudgudgeon]

It had some shaft play,to the point where I had bought a rebuild kit ready to put in it, it blew before I did.
I think the compressor touched the housing, the housing has some decent gouges in it, shaft is broken, the compressor wheel reduced to fragments which ended up in the engine and damaged pistons (burnt beads of aluminium from compressor visible in pic), thrust washers were broken and peices ended up in the sump.

there is a couple of random parts in the pic, but you get the idea


No intercooler fitted.

 

[onefsatchevy]

Wow that sucks... note to self - don't run 22psi!!!!

 

[Big Blue 84BJ60]

damn thats horible im so sorry to hear that
were there any warning signs before the turbo blew or just boom??
is it a ct-26? my compressor wheel cost $20 bucks off ebay and ive see ceramic turbo propeller shafts go for $120 us

 

[mudgudgeon]

there was no real warning, it had made some unusual noises, but I now put that down to a exhaust leak at dump pipe flange. As said I was aware shaft play was getting dubious

turbo was standard ct26

When it blew it was running great, then it went with a loud POP, lost all power and smoke pouring out the tail pipe. took 30-40 seconds to get clear of traffic and off the road and shut it down, by then the engine was burning its own oil.

On the up-side, my engine still has plenty of life left in it, everything looks new inside, apart from damaged pistons. I know it will have new bearings seals etc throughout.

 

[Dutchie]

At 22 psi it creates twice the heat during compression... for 11 psi the temp rise is around 70°C .. for 22 psi the rise is 140°C so the compressor wheel might have gotten too hot... The clearances are different too at the higher temp which could have added to the damage and also spins a lot faster (around 50%) to create that extra pressure so the combination of all seems to be too much.

We make huge turbo compressors and blew a few up due to the same reason (but they were the compressor part only driven by a 700 kW diesel through a gearbox, 20 cm impeller spinning at 45000 rpm and pushing 10.000 m3/h of air at 36 psig)

 

[Cañonero]

If you locate the EGT probe after the turbo, ¿can you anticipate turbo failure due to high EGT'S caused by the turbo running too hot?.

The problems is, how do you know if the high EGT'S are being generated by the engine or by the turbo?

 

[Dougal]

If you locate the EGT probe after the turbo, ¿can you anticipate turbo failure due to high EGT'S caused by the turbo running too hot?.

The problems is, how do you know if the high EGT'S are being generated by the engine or by the turbo?

EGT's are generated in the combustion chamber, everthing downstream of that acts to cool the EGT's.
Your cylinder head ports and exhaust manifold conduct away heat and the turbo extracts energy as heat to power the compressor side.

An EGT probe downstream is really for interest only.

I blew a turbo a few years back when the oil feed line came apart. Luckily I was able to stop before the engine ran completely out of oil and the turbo died properly. A rebuild kit salvaged mine and I'm still running it now.

 

[Tapage]

If you locate the EGT probe after the turbo, ¿can you anticipate turbo failure due to high EGT'S caused by the turbo running too hot?.

short answer not .. actually IMOP the turbo don't let you know until it's too late .. so you need to go ahead and keep your turbo inside the best turbo map island VE and PR for your application ..

 

[Adam B]

As said I was aware shaft play was getting dubious

Radial or axial play? Or both?

I have a small amount of radial play, but not enough to make the compressor touch the side of the housing. I haven't measured it but I can feel slight movement when I try to wiggle it.

I can't produce any axial movement and my understanding is that any amount of axial play is a bad sign of things to come...

 

[cruisedeisel]

how long were you running up to 22psi? i put my turbo on at 450+kms and i've been running up to 25psi on my 3b, goes like stink, think she'll blow? Its not like i drive at that boost all the time, just passing and lifting up skirts. i cruise between 5 and 15 psi. TIME WILL TELL

 

[mudgudgeon]

turbo had some axial and some radial play.

I was running 22psi for about 6months and 15-18psi for 12months prior to that.
I think I will limit it to 18psi from now on, turbo sound changed above 18, it went like a cut cat , but not keen on another rebuild