How much turbo boost? (1 Viewer)

[nickw]

I saw in the Intercooler thread that stock boost on a Cummins 4BT is 25 psi!

Which got me thinking.
My 1HD-T gets about 11psi of stock boost.
How much could that safely be turned up?

I would not want to turn it up to the point of damaging my engine.
But how much boost can we safely run?

I noticed that stock domestic diesels (ford, gmc, dodge) with intercoolers seem to run the the 20-30 psi range. Does adding an intercooler mean we can turn the psi up more?

Thanks,
Nick

 

[brownbear]

I noticed that stock domestic diesels (ford, gmc, dodge) with intercoolers seem to run the the 20-30 psi range. Does adding an intercooler mean we can turn the psi up more?

Thanks,
Nick

Yes, I think the key is the intercooler. Because when you start going above 15 psi the temp of the air exiting the turbo is too hot, and you start lose benefit of the compressed air. Once intercooled the psi can be cranked up quite a bit more.

I think it would be fine to higher than 11. But Toyota designs for longetivity. Running 25psi isn't going to make things last longer. But most of the cummins crowd probably don't care to see 500k plus out of there pick up. The standard NA owners still only own vehicles for a couple years, then get new.

Other problem on your 1hd-t might be getting enough fuel into it to make use of the extra air.

Having a power craving?

 

[VTCruiser]

diesel engines can handle lots more than 11psi of boost. hell, my gasser saab runs 15+psi stock and i have seen those engines run 25-30psi on stock internals. It is not uncommon to see DI diesels reliably run well over 30psi of push granted you have the fuel and cooling to do so. I'd expect the same from the 1HD-T just don't forget about your BEB's

 

[nickw]

BEB are already changed.

As far as wanting more power, the answer is yes.
I live in the mountains. It would be nice to be able to pull up the mountain passes with more power. As it sits now I always to 3rd at about 70kph.
I would like to be able to hold the OD at 100 kph (even with some wieght in the truck).

I realize the Land Cruiser is not built for speed. But if I can get free power and an increase to MPG and not hurt my truck I am very interested.
I really like the idea of having a bit more power and almost 30mpg.

If it is going to cost me MPG or longevity than no thanks.
Other than the intial cost adding an intercooling sounds like free power.
In fact it will even pay for itself in about 1 year or so. SAFARI says adding thier intercooler give 25% more HP and 28% more torque.

If turning up my boost gives me more power and does not cost MPG or engine longevity then I am all over turning it up some more. Don't have to be crazy here.

Stock I have 170hp and 270ftlbs.
If I could get that to 225+hp 370+ft pounds I am sure that it would be enought. Adding an intercooler would almost do that. I just though turning my boost up to the 15-16psi area might help too, as long as no damage is done to the engine or MPG.

I would probably also need to add a tranny cooler, but I am okay with that. I might add one anyway just to be safe.

Right now the highest temps I have seen are 900', and typical being around 650 on the highway.


Cheers,
Nick

 

[Tapage]

I thought in your ide range would be easy add a intercooler setup ( tray to gain some HP and torque at mountains, that means to me speed to refresh your intercooler ) and boost up to 14 PSI .. is pretty safe IMOP ..

 

[brownbear]

Start by increasing your boost with a boost controller to 15 psi and turn up the fuel so you see 1100 on a the hills.

Just do it! the ole nike saying. Do the 15 psi, then look into an intercooler.

 

[nickw]

Will doing this cause a gain or loss to my MPG?

My thought was by turning the fuel up, and by turning the boost up, my engine would not have to work so hard so I might save fuel? Good or bad logic?

Cheers,
Nick

 

[Greg_B]

Right now the highest temps I have seen are 900', and typical being around 650 on the highway. Cheers, Nick

I forget. Are you post or pre turbo with the probe?

gb

 

[brownbear]

Will doing this cause a gain or loss to my MPG?

My thought was by turning the fuel up, and by turning the boost up, my engine would not have to work so hard so I might save fuel? Good or bad logic?

Cheers,
Nick

Sure, but holding it at 100 negates(spelling??) that effect.

You have more power use more fuel.

Turning up the boost with no fuel increase will give you no more power. But will help you use the fuel more efficent and keep temps lower. So to say. Theorys at best IMOP.

Try it out. You have a boost and pyro installed. Go for it.

Take a pair of small visegrips and pinch the hose to the wastegate. It will get no air to actuate the wastegate. Then you can see what your turbo puts out max!

Seriously thou, I bought a 1/8 tee and plug, put in a spring with a ball bearing and some barbed connections on the end and made my own boost controller. No way of knowing if it worked, as I am not driving this thing yet. But I got the idea from THe Dude. 10 bucks of materials. Then you could drive around setting up how high to have the boost hit.

Go for 15 to start.

 

[nickw]

I forget. Are you post or pre turbo with the probe?

gb

Greg:
I am pre turbo.
Very close to the center of the manifold above the turbo.

Brownbear:
I might try adjusting it.
I am actually driving to Kamloops tonight over the rogers pass.
Is there a quick way to adjust it. Something I could pull over and do and then get back in to check. 15 psi sounds safe over the long haul. I don't have to adjust my fuel tonight. Then I could see if my temps go up or down.

Cheers,
Nick

 

[brownbear]

Greg:
I am pre turbo.
Very close to the center of the manifold above the turbo.

Brownbear:
I might try adjusting it.
I am actually driving to Kamloops tonight over the rogers pass.
Is there a quick way to adjust it. Something I could pull over and do and then get back in to check. 15 psi sounds safe over the long haul. I don't have to adjust my fuel tonight. Then I could see if my temps go up or down.

Cheers,
Nick

I was going to say remove the wastegate line, but I do not want you to damage anything.

if you did try the line off be very very CAREFUL I have no idea what these turbos can make for boost uncontrolled. Behmoth60 said he runs his 3b at 20 psi......

 

[Entaran]

Your MPG will die in the arse up the hills because you're boosting the whole way up flat out. This is simply because to make power you burn fuel. If for isntance your Airfuel ration is 20:1, you have 20 parts air to 1 part fuel. What happens if you increase your boost? you increase the air. Increase the air, the ratio goes out... to hold the ratio properly, it ... adds fuel.

Increasing the boost is great and won't affect your MPG unless you actually use it.

The SAFARI D-Tronic computers take 78 series troopies from 11psi to 18psi. Gives it a good whack in the guts. Fit an intercooler (water-air if you can afford) and go from there. Sky's the limit with a 1hz bottom end (which is what a 1hd-t has). I've seen 40+ psi out of one for 100,000 kms. Didn't last much past that though. Then again, didn't have an easy life.

 

[Mountain Goat]

=just don't forget about your BEB's

Help educate a noob - What are BEBs?

Thanks.

 

[wussyPup]

What are BEBs?

BEB == the big end bearings in the connecting rods. These are a weakness in the 1HD-T turbo diesel, and some people think are also a problem in a turboed 1HZ.

Here's a post showing my replacement, https://forum.ih8mud.com/showthread.php?t=97003

g'luck, -Steve

 

[Greg_B]

BEB == the big end bearings in the connecting rods. These are a weakness in the 1HD-T turbo diesel, and some people think are also a problem in a turboed 1HZ. -Steve

I've seen enough in person, and know a shop or two that have seen enough pitting on HZ connecting rod bearings that it is standard replacement now for us. Cheap insurance.

If I bought a truck with an HZ, and if I know the history, then I might be inclined to just run it...if talking personal truck. If it came fitted with a turbo, or I was going to turbo it, then I would certainly be planning to do the connecting rod bearings with ACL's as a standard maintenance item relatively soon.

Mountain Goat, not on the radar as an issue for your 12HT.

gb

 

[Martin White]

Nick, I was wondering if you ever adjusted your boost and if so, what were the results?

 

[nickw]

Hello Martin.

No, I never did adjust the boost.
After reading the threads about intercoolers I decided not too.
Seems as thought the benifits of boosting start to diminish after 12psi (air to hot), so until I add an intercooler (could be years away) I am going to leave the boost.

I should also mention that my boost if probably closer 12 psi. I was reading the guage on a slight angle. When I look at it sqaure on when at max boost its about 11.75

Cheers,
Nick

 

[Entaran]

Just thought i'd add that the point at which the air becomes too hot to use is 12psi. There is NO POINT boosting past 12psi without an intercooler.