Volkswagen Passat Forum banner

98 B5 1.8T - got boost?

1004 Views 9 Replies 7 Participants Last post by  chunky
Hmm... I have a Wett chipped 1.8t. I have been happy with the car, but nnoticed that "engine" sound is quite loud, especially since I changed the TB, water pump, belts, etc. I also replaced the radiator... earlier this year.

I drove my friends stock 00 1.8T Jetta and the car seems much quicker. Maybe it's because of auto tranny, and the greater torque off the line? But I could hear turbo whine a lot clearer... and definitely less "engine" sound.

Which made me wonder if my car's turbo is not working optimally.

What are some basic diagnostics to confirm? I don't have a boost gauge, but thinking of getting one for this reason.

Suggested diagnostics?
1) Check Boost pressure
2) Check turbo lubrication?

What else?

1 - 10 of 10 Posts
Check your vacum hoses first. One hose goes from the front of the intake manifold down to the DV. The other one is short and goes from rear of the intake manifold to the FPR.

Then if the hoses are OK let the car cool down overnight and in the morning (with the engine completely cold) try to move the wastegate rod. It is the rod coming out from the gold colored piston mounted to the turbo. If it moves at all then the wastegate is gone and does not close. This was one of the problems on cars that did not have oil line heatshield installed (97 and early 98 cars).

If the wastegate is OK, then I would replace the DV. If it's the original that come with the car, then 99% it's blown.
Remember that the Jetta is about 300lbs lighter and might even have a K03 Sport turbo while you only have a Sport. I would say that your power output is close to his, so the weight advantage would make his car seem quicker.
thanks for the tips...

Boris, I'll check on the wastegate rod... I've already replaced the vac hose with silicon stuff. And the dv is a forge already.

Maybe it really is a power-to-weight ratio thing. But really remember hearing the whine of the turbo before, even though it was faint. But in the Jetta, it was quite clear.

Oh well... I'll have to check it out more. I'll post back.
i thought i was the only one who noticed that, the jettas seem to have a more louder/clear turbo sound, and less "engine" noise.

although, i can still hear my turbo, but i can hear the motor too!!

maybe its the jetta exhaust :crazy:

The Intake and DV valve are in a different place on the MKIV's. The B5's have the DV under the front right corner of the car which makes the turbo almost silent. If you want to hear the turbo spool, i suggest flipping a Forge closed loop DV valve with a EVOMS cold air intake... it will make that baby chirp like she's never chirped before.
you mean fliped as in having the spring loaded port sonnected to the intercooler hose, and the other to the return line???
Chunky you will hear the turbo on a Mark IV car more pronounced than on a B5

The reason is the turbo is closer to the cabin because it is at the back of the engine right behind the fire wall.

Your passat's turbo is further forward and the catalytic converter is closer to the passeger footwell so more exhaust noise with resonate into the car.

If you have you car chipped you should be able to hear the boost going into the throttle boby right before the pressure drops off when you are still in first gear.

You can't compare apples to oranges longitudinal to transverse. beside the engine code on the Jetta is different to your 98 AEB there have been some minor revisions to the the 1.8t block so that may also account for reduced valve train and exhaust noise.
I just saw

I have a question (maybe dumb)... I peeked under the hood and I have no idea where to look for the wastegate actuator. I see the turbo, but not sure which end to find the wastegate rod. Is it forward or aft? left or right? Under or beneath the turbo. Do I have to remove the airbox, etc to see it?

Looking at HermanH's write-up in the info section, are there any pics showing the wastegate rod?

thanks...ttyl! :)
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.