11 replies to this topic

[ThaBigO]

I was wondering on how adjusting your wastegate can help the boost sistuation that most people have?? How extactly do you adjust the wastegate, is there some sort of guide?? Im suppose to be boosting 17 Psi with the SpeedTuning ECU chip but im only getting 14-15. Could this be something with the wastegate?? Also when i drive on the Highway and i hit around 65-70 mph my Rpms don't go below 2000. I let of the gas and it still stays on around 1900-2100 Rpms. It starts to go down once i apply the brake and go below 50 mphs. Is this normal??? Why does the car do this??

Thanks,

BigO

[BlackT5]

Here is a link to IPD's instructions on adjusting thewastegate.

http://www.ipdusa.com/pdf/wastegate_adjust...94_02_turbo.pdf

When you drive on the highway, your rpms won't go below 2000 because of the gearing in the AT. Even with my 5-speed, i've pushed the clutch in to change to 5th, but I was already there. I need a 6 speed!

[TorqueSteer]

I also have a 95 850 and I cant get over 14-15 pounds to redline either, even with open wastegate or a MBC set to 17-18 psi. The 15g is pretty much limited to 14-15 psi at redline from my experience. Ive also noticed that boosting anything over 15-16 pounds on a 15g wont help you because it becomes extremely inefficient and just pumps hot air. I have also heard that the conical outlet to the downpipe on the 95 850's may also be a boost limiter to about 14-15 psi at redline.

Edited by TorqueSteer, 19 October 2004 - 04:04 PM.

[ThaBigO]

Hmm i c, well im gonna try and see about adjusting the wastegate. Am im probally gonna order a downpipe by the end of this week or begining of next week. But im not Hitting 17 or 16 psi at all. Im just trying to get 17 max. Dont wanna be pusing more with the stock Turbo. I heard that we can push 18-19 with the right mods though.

[TorqueSteer]

Be very careful not to turn the diapragm when adjusting the wastegate, only turn the screwed in part (cant remember what its called).

[jross]

No offense, but adjusting the wastegate is really not a great idea on these cars. The gains (if any) are temporary anyways (your ECU adjusts for them). You're probably running into the limitations of the 15g turbo, and mucking with the wastegate isn't going to solve anything long-term -- only increase your chances of breaking stuff.

[nik850r]

Be very careful not to turn the diapragm when adjusting the wastegate, only turn the screwed in part (cant remember what its called).

a while ago i tried adjusting the wastegate back to normal. i wasn't thinking and twisted the arm not just the part that has the screw threads. i twisted it back, but what could happen?

[J0E]

Also when i drive on the Highway and i hit around 65-70 mph my Rpms don't go below 2000. I let of the gas and it still stays on around 1900-2100 Rpms. It starts to go down once i apply the brake and go below 50 mphs. Is this normal??? Why does the car do this??

Yes...this is normal. This is because our cars are fitted with a feature commonly known as the "transmission." When coasting, your RPMs can only drop as low as your tallest gear will allow given your speed and tire size, as long as you are in gear and not in neutral. Cars without transmissions do not exhibit these characteristics.

And don't touch the wastegate.

[theunderlord]

Also when i drive on the Highway and i hit around 65-70 mph my Rpms don't go below 2000. I let of the gas and it still stays on around 1900-2100 Rpms. It starts to go down once i apply the brake and go below 50 mphs. Is this normal??? Why does the car do this??

Yes...this is normal. This is because our cars are fitted with a feature commonly known as the "transmission." When coasting, your RPMs can only drop as low as your tallest gear will allow given your speed and tire size, as long as you are in gear and not in neutral. Cars without transmissions do not exhibit these characteristics.

And don't touch the wastegate.

Sweet, where can i score one of those "transmissions" you speak of? are they pretty expensive?

[850 GLT]

Yes...this is normal. This is because our cars are fitted with a feature commonly known as the "transmission." When coasting, your RPMs can only drop as low as your tallest gear will allow given your speed and tire size, as long as you are in gear and not in neutral. Cars without transmissions do not exhibit these characteristics.

And don't touch the wastegate.

Rofl!! Well put!

[TorqueSteer]

Be very careful not to turn the diapragm when adjusting the wastegate, only turn the screwed in part (cant remember what its called).

a while ago i tried adjusting the wastegate back to normal. i wasn't thinking and twisted the arm not just the part that has the screw threads. i twisted it back, but what could happen?

The problem is that the rod is connected to a rubber diapragm, like all rubber on our cars it becomes weak and brittle after many years of use. When you turn the entire rod you are turning and possibly flexing the weakened rubber. But if its broken already, youll probly notice it.

[ThaBigO]

lol i c, see after i got my cat back put it i relly never noticed it. I guess i notice it more becuase it louder and i feel the car pull more.