low vac while crusing

[Quadsportz]

My dsm runs 5 hg of vac to 0 boost on the interstate just to maintain at the same speed. Is this normal? 0 boost I mean like its on the verge of boosting if I press the gas more it will boost.

 

[Xploitn]

Hopefully someone chimes in for you that knows more than I, but here is my logic:

Boost leaks make the turbo work harder than it should have to. A boost leak might also result in lower vacuum.

Have you performed a boost leak test?

or else try reading this thread:
http://www.dsmtuners.com/forums/newbie-forum/466461-low-vacuum-but-drives-great.html

 

[stunt2]

have you got afr gauge ? if yes, what's the reading

 

[iBoostDSM]

Perfectly normal. As long as your idle vac is in spec, you're fine.

 

[curt-s]

Also helps to know what speed you're at in what gear when you're seeing 5.

The higher the engine rpm and vehicle speed, the more load on the engine even at cruise to maintain that speed. I've never broken 10 even at over 100km/h cruise though, but that's just -my- engine and 14b.

 

[Quadsportz]

There's no boost leaks. 21 hg vacuum at idle. I only see 15 vacuum when cruising if I'm going downhill. This is my first turbo car it just seems like it shouldn't have to be running out of vacuum and on the verge of boosting just to maintain speed. I have no wideband car is all stock except for an exhaust. It used to cruise at a higher vacuum before I put the exhaust on.

 

[DRTredHEAD]

There's no boost leaks. 21 hg vacuum at idle. I only see 15 vacuum when cruising if I'm going downhill. This is my first turbo car it just seems like it shouldn't have to be running out of vacuum and on the verge of boosting just to maintain speed. I have no wideband car is all stock except for an exhaust. It used to cruise at a higher vacuum before I put the exhaust on.

If your on stock turbo stock cams cruising 65-70 in 5th that sounds about right. The 14b turbo spools around 2500-3000rpm which is where you'd be cruising at that speed, t25 is even less.