Does the BOOST GUAGE need calibrated after replacement?

[Pantera1]

Does the BOOST GAUGE need calibrated after replacement?

My boost gauge died last fall. I found a couple of used ones. I finally got some time to replace it. The first replacement gauge did not work either so I got to pull the dash array again and try the other used one. This one works but I don't think the reading is right. The needle zeros out with ignition but at startup it shifts to 20 mmHg negative boost. I can't drive it to check its response because Iowa is still having winter but upon warm up hitting the throttle will drive the needle up to zero or a little better. Is this gauge bad too or can it be calibrated? I have disconnected the battery a couple of times to see if it would reset but no luck. All other gauges work perfectly. Sorry so wordy.....any ideas would be greatly appreciated. :confused

 

[shelbyelite]

No, there is no calibration. Further, I do NOT recommend buying used gauges. Most likely, if the gauge is out of another car, it is/was bad.

 

[Pantera1]

I was afraid that would be the case. I had bought a couple of instrument arrays from wrecked GT's for extra parts. I suppose I'll just use them as paper weights. :ack

 

[BlackICE]

I was afraid that would be the case. I had bought a couple of instrument arrays from wrecked GT's for extra parts. I suppose I'll just use them as paper weights. :ack

If you bought the whole array from a wrecked car I would be that most of them are OK. Single gauge?

 

[Pantera1]

Back to the drawing board. This time I used my one and only NEW boost gauge! The new gauge is showing the same neg 20 mmHg boost at idle as the used one I tried. It also moves to zero at ignition but drops to 20 once started. Hit the gas and up to zero or a little above....then back to 20. Could a sensor on the engine be sending an erroneous signal?

 

[BlackICE]

Back to the drawing board. This time I used my one and only NEW boost gauge! The new gauge is showing the same neg 20 mmHg boost at idle as the used one I tried. It also moves to zero at ignition but drops to 20 once started. Hit the gas and up to zero or a little above....then back to 20. Could a sensor on the engine be sending an erroneous signal?

Seem like normal operation to me. I is hard to get boost in neutral; You don't get any boost until your run the car on the road with more than 50% throttle and high load. Drive it at about 30 mph in 3rd, press the throttle to the floor the boost should quickly go to 12 pSI on a stock car, pinned with pulley and tune. With a Whipple it should also pin quickly, but that depends on the tune file used.

 

[Pantera1]

Ok. I'll try it tomorrow if the weather is decent. I was thinking at idle it would normally read zero boost. Pretty sad, I haven't driven the car in so many months I can't remember how the gauge behaved.....:frown

 

[HHGT]

If you bought the whore?

Huh??

 

[BlackICE]

Huh??

I guess that is call a "Freudian typing" :lol

 

[nota4re]

It also moves to zero at ignition but drops to 20 once started. Hit the gas and up to zero or a little above....then back to 20.

This is PEFECTLY normal. The only time the boost gauge will get messed up is when you put a tune on your car that includes a MAFia. Most pulley tunes don't use the MAFia, but a Whipple upgrade likely will. So, if you are stock or even if you plan a typical pulley/tune in the future, your boost gauge is fine.

 

[BlackICE]

My car has a Whipple and Mafia and my stock boost gauge works perfectly! Of course it is pinned rather easily. I have a self rolled custom tune that has a correctly scaled MAF transfer function so that the stock ECU's inferred boost calculations still work. The technique is only good till about 900 RWHP, after which you the MAF table tops out at 64Kg/min. Then you will have to follow the recommendations of SCT in scaling for a Mafia and the gauge will not read correctly anymore

Every aftermarket tune for a Whipple I have seen used the method that SCT recommends so the boost gauge doesn't work correctly.

 

[nota4re]

Great job, Clinton! See you soon at the Mile!

 

[BlackICE]

Great job, Clinton! See you soon at the Mile!

I look forward to the event and meeting you and all the other great FGT owners again. However I doubt that I will go ever go as fast as Ryan.

Are you going to run your car?

 

[nota4re]

Nah, I'm gonna have to get a Gurney bubble and/or a seat mod. I scrub the headliner as it is (my height is in my torso and not my legs), and with a helmet, I have to recline the seat so far that I am in just an absolute foreign seating position. I'm sure we are going to have so much fun watching everyone run and keeping everyone safe - there won't be time for driving!! LOL We have 4 brand new sets of Hoosiers and one new set of Bridgestone's here.... getting obvious that there's an even right around the corner! See you soon.

 

[shelbyelite]

As Kendall said, this is normal. You will get a negative reading at idle. You will only get a zero reading whenyou turn the key on without starting the engine