Boost Pressure Numbers???

[Max Wedge]

I finally added the gauges yesturday--Autometer 0-35 boost, 0-1600 pyro, trans temp. Now my question is what type of boost numbers should be normal for my application?



Boost is taken from intake air horn drill & tapped on back side, EZ box on 3rd setting (factory)w/Boost elbo, stock injectors, stock TC, 4. 10 gears, Ray's Banjo-bolts--all 5.



So far I have seen a Max of 24 psi empty WOT up hills and even on level ground, I thought it would be more. EGT's are 1000 max.



I also have a 4 psi pressure switch in Injection Pump banjo-bolt connected to a light mounted in A-piller--light will flicker, when WOT, but will go out. See signature for truck bio.



Max

 

[John Berger]

In my configuration I've seen a max spike of 28 psi. I haven't pulled my trailer up any good grades in this configuration yet, so I have no way to know if that will make a difference.

 

[Amianthus]

What you are getting for readings sound about right to me. You may see a spike a little higher than that, 26psi or so, but you are running about right.

Why do you ask? Do you think you need more? We can help you with that, you know.

 

[Max Wedge]

Why do you ask? Do you think you need more? We can help you with that, you know.



Amianthus, I know you guys could help out with more---this board has cost me more money in the last year that I care to count



And yes, I will eventually want more, but since I didn't have a base line of stock boost, I thought that 24 psi seemed 'kinda low. Next item is loosing factory muffler--any suggestions--I will be keeping the original exhaust though. then 275 injectors, 2nd lift pump then Bill's converter, then I will be DONE I think



Max Wedge

 

[chuck3]

Max Wedge, Thats about the same as I get, pretty much same setup as you!

 

[Ramafid]

I have about 25 psi also,so that seems about right. I was a little concerned about your 4 psi light coming on at wot. My origional lift pump would go to 3 psi and I thought that was too low. I bought a new one and moved it to the framerail and never drop below 9 psi at wot. Just something to think about.

 

[KWIKKURT]

One thing I've learned is more boost is not always better. It needs to be matched with the fuel amount, and engine needs. Too much boost is a waste of power. Also it is easy to overspeed the turbo and which will take you out of the efficent map area of a given turbo(and can cause massive turbo failure!). What happens is the turbo will heat the air more causing it lose some of the density. . =loss of power and higher EGT's. The stock turbos seem good up to 28-32 psi. I had my hx35 over 44 psi. It did not run any better than at 32 psi. When I changed to my bombed hx40 at 32psi the power seems better, there is much less smoke and lower EGT's. This indicates that the hx40 is moving more, denser /cooler air. (after all it has larger wheels).





Do a search or two. TED JANETTY did a post on this a few months ago and he explains this with much more knowledge / experience behind it.



IMHO..... Smoke Is GOOOOOOOD

 

[Mundgyver]

If you want to see the boost come up over 30, then you just need to give it a little work to do. 2500 lbs in the bed sounds about right. On a serious question though, when you moved up to the HX40, what did you mpg do??

 

[KWIKKURT]

I have not been watching the mileage that close. It has improved over stock atleast 1. 5-2 mpg. . I tow so many different loads and have been changing turbos and injectors alot lately working on trying to see how much of the massive torque we can use towing. I am working on ways of keeping the egt's down with out losing driveability. I love the HX40 the only issue is turbo lag. I hope to test one more configuration and then will post results. I love the setup I have now. It is a Holset stock center section and wheels with a bombed turbine housing. I have a housing that I have to send off for outside work when it returns I will test and then find a few others to R&D on the two steups on different trucks. BOMBS AWAY!!

 

[Chad Sheets]

I have had my boost upto 49, might have even hit 50. I got to thinking after I did that and readjusted my wastegate. Now I stay in the 35-45 range when on the throttle. I would hate to blow a head gasket or worse. 45 is more than plenty for me.



PS Happy B-day Max Wedge!!! I hope you enjoy the day and reflect on all the good things you have done up to this point. Happy Birthday!