"Safe" boost?

[RLDSL]

Ive got a set of instructions for a Hypermax turbo kit in front of me here and they state not to excede 12 psi. Considering all of the testing and racing that they have been involved with , with these engines, I would be inclined to pay attentention to them. and those folks are not shy when it comes to pushing an engine, so when they throw out a figure as a max, that shouldnt be considered a figure to start from and push from there.... theyve already done that
Its great to learn from your mistakes, but far better to learn from the mistakes of others

 

[The Warden]

Ive got a set of instructions for a Hypermax turbo kit in front of me here and they state not to excede 12 psi. Considering all of the testing and racing that they have been involved with , with these engines, I would be inclined to pay attentention to them. and those folks are not shy when it comes to pushing an engine, so when they throw out a figure as a max, that shouldnt be considered a figure to start from and push from there.... theyve already done that
Its great to learn from your mistakes, but far better to learn from the mistakes of others

VERY well put IMHO.

 

[wmoguy]

15-22 psi for a year on head bolts. No issues

With good gaskets and flat heads I'd have no qualms running 15 psi.

I think what's missed ALOT is talking about boost pressure. Look at drive pressures. I can almost guarantee you the stock turbos are showing close to double the drive pressure ratio to boost. That'll lift heads right there.

 

[Black dawg]

15-22 psi for a year on head bolts. No issues

With good gaskets and flat heads I'd have no qualms running 15 psi.

I think what's missed ALOT is talking about boost pressure. Look at drive pressures. I can almost guarantee you the stock turbos are showing close to double the drive pressure ratio to boost. That'll lift heads right there.

and drive pressure is very different from each of the available turbo kits. And I dont think 12psi is an accurate figure as to gasket/or engine longevity, but I dont know how one can be worked at much more than that power level without overheating issues.

When I was putting 20psi (intercooled) to my almost 300k 7.3 I was not concerned about the engine, but sustained boost of over 10psi/1000egt brought coolant temps up uncontrollably fast.

 

[88 Ford]

IMO a lot of the heating issues are overcome by having a more efficient turbo that doesn't produce as much heat. Lower temps in will usually be lower temps out. For instance if a more efficient turbo drops IATs by 200*, chances are that egts will drop comparatively as much. And also like Wmoguy said, drive pressure is another big factor. There is definitely a lot to be improved on with the turbos available for these engines. And also like I said earlier temperature had a big multiplication factor with cylinder pressure. I'll see if I can find the info about what I read...

 

[Black dawg]

IMO a lot of the heating issues are overcome by having a more efficient turbo that doesn't produce as much heat. Lower temps in will usually be lower temps out. For instance if a more efficient turbo drops IATs by 200*, chances are that egts will drop comparatively as much. And also like Wmoguy said, drive pressure is another big factor. There is definitely a lot to be improved on with the turbos available for these engines. And also like I said earlier temperature had a big multiplication factor with cylinder pressure. I'll see if I can find the info about what I read...

adding the intercooler lowered intake temps around 100 deg,( on an 80 deg day iat was never over 120) but coolant temps were very hard to control after adding the intercooler. More power makes more heat. I did determine that I was still getting good airflow through the radiator. (coolant would lose 100-120deg from top of the radiator to the bottom.

 

[SparkandFire]

I run 7 PSI MAX on the 1985 Vintage 6.9 with factory head bolts.

I had the Wastegate plugged off when the 7.3 was under the hood, I got 12 PSI out of it then.

Someday headstuds/head gaskets may be in my future, but for now, I HOPE 7 PSI doesn't lift the heads.

 

[FordGuy100]

I run 7 PSI MAX on the 1985 Vintage 6.9 with factory head bolts.

I had the Wastegate plugged off when the 7.3 was under the hood, I got 12 PSI out of it then.

Someday headstuds/head gaskets may be in my future, but for now, I HOPE 7 PSI doesn't lift the heads.

I ran 9psi wastegated for about 25 thousand miles. You should be fine

 

[88 Ford]

adding the intercooler lowered intake temps around 100 deg,( on an 80 deg day iat was never over 120) but coolant temps were very hard to control after adding the intercooler. More power makes more heat. I did determine that I was still getting good airflow through the radiator. (coolant would lose 100-120deg from top of the radiator to the bottom.

Those are pretty decent temps after the intercooler but also egts add heat to water temps as well. There are just so many factors with all this which does include possibly the turbine housing being on the small side as well. But yes you are definitely correct more power does make more heat. I guess I am making my stance of the heat from other turbos based on what I have seen on other builds. It is just my opinion but I really do think a different turbo makes a lot of difference with egts...