Hey guys

I just installed a greddy boost gauge and i was just wondering if these readings sounded right to you guys. It stays around 13 vac at idle, when im just cruzing, not accelerating, it stays around 5 vac, when i shift down to slow down it reads around 20 vac, and should i have to get on it really hard to hit 10 boost? I mean i really have to get on it to hit 10. Thanks for the help

 

Your boost readings are fine, you shouldn't be boosting unless you're accellerating. all other times you'll be making vacuum. When you're engine braking you're going full vacuum.

 

Alright thanks for the help. I thought that the readings were about right but i wasnt positive because i have never delt with these types of turbos before

 

Does your car follow the 10-8-10 boost pattern that is described in the links in the FAQ thread? You need to drive the car in 3-5th gear to really check boost response.

Also, your idle vacuum is a bit on the low side, is the engine streetported or does it have high mileage?

 

In 5th gear it should be easy to get 10psi when you're at/above 3000rpm. All the way down at 1st or 2nd gear you need to put your foot on the floor to hold 10psi.

Dave

 

Are you non sequential? That makes a difference as well.

 

As alluded to above, the higher the gear, the more load, the faster you'll see boost---but the slower you'll move up through the rev range.

I agree that 13 inches of vacuum is very low unless a heavily ported motor. What idle rpm are you seeing that vacuum at?

 

Hmmm, well its not a streetported motor, and it does have around 20k on the motor. My car does idol alittle low, around 800. I went out and drove it again and did notice that the only time it was hard to sustain 10psi was in the lower gears, it was much easier is 5th. But since everyone is saying that the vac is low, what does this possibly mean? Oh and i am just runing the sequential turbo setup

 

It means you may have a tired motor. It may have 20k on the seals and whatnot, but might have higher mileage on the rotor housings. I wouldnt worry about it too much, as long as the car is running good that's what's important. If it bothers you, you can always go ahead and get a compression check done, that's the real way to get your answer.

 

It is very possible that there is quite a bit more on the housings etc. I bought the car from my aunt about a year and a half ago. She had it about a year and put 2 motors in it during this time. It was their backup car and when they drove it, which was only about once or twice a month, they drove the living hell out of it. But right after they had it rebuilt for the last time, along with the turbos, and had silicon lines put in, i bought it from them for 5k because they just wanted the car gone. Im not sure who did the rebuild but the car runs strong, just as strong as it did the day i bought it. It also smokes alittle when its started up the first thing in the morning but it goes away once the car warms up, i have read this is normal right? Also i have a greddy oil pressure gauge that im going to put in, can someone send me a like to the best place to buy the piece that greddy makes that goes under the oil filter that allows a place to put the sensor for oil pressure and oil temp?

 

It's possible that the boost gauge, itself, is not accurate.

Tee a known good one together with yours (or replace yours with a known accurate one) on the car and see if they read the same.

Or, out of the car, check your gauge against a known accurate one. Tee them in together and put pressure on them and see if they read the same. Do the same thing for the vacuum side using a "Mityvac" or something similar.

Your readings won't mean much if the gauge isn't accurate.

Dave

 

For 5k, you're doing fine it sounds like to me! Don't worry to much about it, but make sure you have an engine fund available if needed or alternative transportation.