How much boost on turbo conversion?

[DrCharles]

I'm about finished putting a factory turbo setup on my '93 7.3 NA. I've done plenty of reading on how much boost is safe and what engine mods are required to support it, so that's not what I am asking

My question is, how much boost should I expect to see on the gauge before turning up the pump from factory NA setting? 2-3 psi? Or none until I add more fuel?

 

[renjaminfrankln]

EGT's are what you should be concerned about. Fuel will affect boost somewhat as the exhaust pressure is higher with more fuel at a given RPM, but for tuning purposes with a factory turbo that is irrelevant.

 

[Thewespaul]

Dont really worry about what boost you see driving with the na setting, you can find out if your setup is tight by slowly raising the engine rpms up in neutral and you should see some positive intake pressure between 2000-2500 rpms. If you dont, you have boost leaks. Look for leaking oil for an intake side leak, and soot for an exhaust leak.

 

[DrCharles]

EGT's are what you should be concerned about.

Thanks, I also have installed a pyro and will keep an eye on it under load. This isn't my first modified turbo engine... but it is my first turbo diesel

That said, boost isn't really irrelevant as I have (new) head bolts holding my rebuilt heads down, not studs... I have tweaked the wastegate three turns but will make sure it's under 12 psi at all times.

 

[Thewespaul]

Not saying boost is irrelevant, just that the amount of boost you will have at a na setting isnt a good gauge for how sealed the turbo kit is because the amount of fuel varies so much with pump wear and how it was setup by the rebuilder. Some people get 10 psi some get none, just depends on how the injection pump is worn and setup. With no intercooler, youll typically run into egt issues before boost issues, but that all varies with altitude, timing etc

 

[DrCharles]

I have no idea what kind of shape my pump and injectors are in, or how old they might be. I know the truck starts readily whether hot or cold, and just a trace of black smoke visible in the mirror when pulling a hill. The odo says 188k but it may well have been substituted from another truck. Doubt it's the original IP but again, who knows.

Meanwhile I'm waiting for the last few parts... flex pipe is coming tomorrow, and my GPC relocation bracket on Friday. That's all I need other than a filter-minder (and really I could fire it up now since the GPC is sitting in its new spot all wired up, but it's too damn cold today & tomorrow to be messing with it!)

 

[Clb]

op
russ told me "don't touch it" my 93 ats 093 hits 9-10 psi maxing out egt's at 1150-75.

Wes you have any input\tech on timing verses egt and mpg on a turbo eng.?
It seems the common thought is to add 1 deg to the base of 8.5 due to the fuel...
A max of 10 deg.
It seems mine likes closer to 8.5...

 

[Thewespaul]

op
russ told me "don't touch it" my 93 ats 093 hits 9-10 psi maxing out egt's at 1150-75.

Wes you have any input\tech on timing verses egt and mpg on a turbo eng.?
It seems the common thought is to add 1 deg to the base of 8.5 due to the fuel...
A max of 10 deg.
It seems mine likes closer to 8.5...

I could ramble for hours about this topic, when I get some time id like to make a thread for a discussion just around egts, but overall less timing tends to be snappier down low and more timing makes more top end. MPG is best somewhere in between, usually 7-8* on turbo engines is where I set them, on na engines they like more timing, between 8.5-9.5* Too far in either direction will start to increase egts, but generally too advanced makes higher egts with a comparably low boost level.

 

[Clb]

I'm pouring boilermakers when your ready .
we need a retired mod who has time to wade thru and update stuff like this.
the tech here is great, to bad you smart guys have to earn a living first.
thanx
Cb

 

[Thewespaul]

Well there’s so much good info on this site I think someone could spend a lifetime wading through all the good tech, I’m hoping to put together some tech info on my site once that’s been put together, but only so many hours in the day

 

[lotzagoodstuff]

I'm pouring boilermakers when your ready .
we need a retired mod who has time to wade thru and update stuff like this.
the tech here is great, to bad you smart guys have to earn a living first.

THAT is good stuff! Vote yourself a raise.....wait a minute: your retired!