Boost Reading

[red-rider]

I have a few dumb questions. My truck is stock and I just finished installing my boost gauge and Im just wondering on what readings I should be getting.



I took the truck out for a test drive, on the freeway I floored it and hit about 33 psi, stayed at about 70mph the gauge then went down to about 7psi, is this correct or did I somehow sprung a leak somewhere? Normal city driving the boost gauge will climb up and then at 35 - 40 mph gauge will read 5 psi and zero at the stop or deceleration or if Im just cruising.



When I installed the boost bolt I didnt put any teflon tape on it, but I did on the hose connections connecting the hose to the gauge and the hose to the bolt. Could this be my problem that I didnt put any teflon tape on the boost bolt to the intake? Also if I disconnect the hose line from the bolt will I actually be able to reinstall the line or would I have to purchase a new hose line and connectors do to the fact that the hose gets pinched when installed to the bolt and or gauge?



My question is should I be getting different readings? Does the turbo only work on certain situations? Do I need to bleed the gauge? What reading should a stocker be getting?



Should I have placed teflon tape or a gasket sealant on the boost bolt?



Thanks

 

[lschultz]

Thats about what mine reads. I think I put some teflon tape on the boost bolt but I would say for stock your readings are normal. Mine runs around 4-5 on the highway at the speed I run but it varies.

 

[RPolidora]

Remember, it has alot to do with the load on the engine. So yes, while cruising at 35-40 there isn't much load so the boost will be low as well as 0 boost at idle.

 

[red-rider]

Thanks guys

 

[SRadke]

A turbocharger is dynamic. As the load on the engine increases it will consume more air/fuel and thus make more exhaust. The exhaust is what drives the turbine in the turbo and creates boost. More exhaust volume/pressure, more boost. The dynamic part of it is that they load dependant rather than rpm dependant like a blower. You can have 0 boost at 2000 rpm (high idle) or 30 psi of boost at 2000 rpm (under load) whatever your engine demands. A blower cannot give you that. Your numbers sound perfect.



-Scott

 

[COSEng]

So far I have only produced about 25-26 psi unloaded. Does an empty truck

generate enough "load" to achieve 30-33 psi??? Does my 03 turbo produce less

boost than and 04. 5.



Thanks,

Carl

 

[SRadke]

The 03's in stock form would not make more than 25-27psi. My 250hp SO would only make 24 psi max. You may see slightly higher boost with a trailer because you have plenty of time to sufficiently load it but it won't be more than a couple psi on a stock truck.



-Scott

 

[nickleinonen]

So far I have only produced about 25-26 psi unloaded. Does an empty truck

generate enough "load" to achieve 30-33 psi??? Does my 03 turbo produce less

boost than and 04. 5.



Thanks,

Carl

the 03-04 can make peak ±26psi boost, the 04. 5-present make more [some claming 38psi stock]... different turbo on the 600/610's...

 

[JVolpe]

My 04. 5 600 stock would peak at 32psi. After AFE Magnum Stage II and Banks Monster exhaust it will spike to 34psi. Just cruising flat terrain at 70 might be 5psi.



Sound normal to me.

 

[JTurk]

I have a 6-sp in my 04. 5. If I get on it when going into 5th I can load it enough to really bring the boost up. When the power picks up and she starts to really pull the boost will shoot to 35 or higher really quick. Then, generally in less than a second it will drop back to 25 to 28. The waste gate opening and bypassing some pressure past the exhaust side of the turbo causes this. As soon as that happens you will feel the power drop a little. As I understand this is done to protect the turbo from being over-stressed.



I would think if anyone is seeing any higher numbers for an extended period of time may have a problem. The final symptom will probably be turbo pieces in the muffler!