Constantly under boost?

[SLC97SR5]

When driving unloaded for long stretches at 80+ mph my boost gauge indicates 3-8psi.

Is there any damage or fatigue occuring while under constant boost?

I have 4.10's,E40D and 265's so while cruising I am around 3k RPM's

While loaded the boost gauge rarely dips below 10psi.

Is there any reason these engines wouldn't hold up to that?

Eventually I would like to upgrade to 285's to gain some additional roll-out.

 

[1994Diesel]

you really should'nt have any problems with that amount of boost with stock head bolts. I experience about the same boost pressures too.

What are your egts with those boost numbers?

 

[SLC97SR5]

Here's a random pic for fun...

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[SLC97SR5]

Unloaded I see 650-850egt at 7psi boost.

Loaded I can easily peg ALL the gauges. 1250egt and 17-18psi are easy to hit if I'm not watching.

 

[1994Diesel]

Do you have head studs? im pretty sure 17-18 psi is dangerous with stock head bolts.

 

[SLC97SR5]

Do you have head studs? im pretty sure 17-18 psi is dangerous with stock head bolts.

No, I am in the danger zone but I only see it briefly.

My original question about consistent boost is what I'm really after.

 

[Diesel JD]

It's more pressure than a N/A motor but the benefit of turbocharging does involve some risk. I think as long as you don't see that 17-18 psi figure very often, but rather keep it to below 15 psi and 1000 egt you really aren't doing much harm. Incidentally I have the idea that the higher boost may be less damaging while the engine is loaded down than just coasting about, based on some discussions we had here awhile ago. I wonder if that is the case? But 3-8 and up to 10 is really nothing and probably very much withing conservative Ford factory parameters.

 

[Worstenemy453]

The higher the RPM's, the more boost can be used effectively. As the RPM's go up the boost is spread out over the cylinders more. Low RPM's and hogh boost can be bad. Any turbo engine at 3K rpm's will have boost no matter what.

 

[FordGuy100]

Might want to back down to 70-75mph?

Nice to know someone around here cruises at a higher RPM than I do

Like said, boost up top is easier on the motor than down low. I cruise all day long at 2-4psi at 70mph, and it hasnt caused anything to go wrong.

 

[NMB2]

I cruise with 5spd and 4.10's at about 2600rpms doing 75, sitting at about 7-8psi and 550* - 600*

 

[crashnzuk]

Pretty much all turbo engines are gonna make some boost while driving down the road. If it didn't, I'd be worried I had a boost leak or a turbo issue. My dad's truck runs around 4psi at hiway speeds. How fast do you drive anyway? I don't even want to calc how fast that is at 3K.
Travis..

 

[SLC97SR5]

Might want to back down to 70-75mph?

I know...I think about my poor injectors popping away, they are really singing along at 80+mph.

I don't make a habit of speeding but when the kids get cranky it's time to get movin'!

 

[dyoung14]

I think at 75-80 im seeing around 6-8 psi, i cruise that way all the time, i see around 15 psi daily for short time periods usaully not longer than a minute or so sometimes i get the wild hair to fly down the road boosting 15psi running 110mph for miles on end but not sure why that urge hits me at times oh well