Boost Guage Flickering

Trinker · Post by **Trinker** » Tue Jun 20, 2017 6:17 pm

Finally just put in the new boost gauge (redundant I know) on my deli, seemed fitting with a new turbo! Anyways, I routed it off off the boost line that goes to the injector pump from the turbo and when I finally fired it up the thing just flickers like crazy, to the point of being noisy. Super disappointing. It is a cheap guage (iEquus) and I've already painted it or I'd just return it and forget the damn thing. Anybody have any idea what could be cause the intense flickering?

lrp374 · Post by **lrp374** » Tue Jun 20, 2017 7:46 pm

Is the gauge a mechanical type or electronic?

Trinker · Post by **Trinker** » Wed Jun 21, 2017 12:54 am

Mechanical, hoping it was just a leak from one of the fittings, will know better tomorrow..

Post by **Growlerbearnz** » Wed Jun 21, 2017 3:29 am

A mechanical gauge shouldn't flicker. I think you're right to look for leaks, I suspect it came with soft silicone hose and it's stretching enough to release the pressure, then snapping back.

I presume it has push-on barbed fittings, try a cable tie around each one to stop it moving.

Killbert · Post by **Killbert** » Wed Jun 21, 2017 4:01 am

Some of those required a copper orifice to be installed in the boost line. This limits the volume of airflow and reduces flutter at the gauge.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Trinker · Post by **Trinker** » Wed Jun 21, 2017 8:38 am

I've tightened up all the fittings. From the t junction on the boost line going to my IP I have about 50cm of heavy guage vacuum line going to the bulkhead, from there it switches to a hard line with brass pinch fittings that goes from the engine compartment up to the guage on my dash, Al nicely run out of sight with no crimps. I'll test drive it again today and see how it does, otherwise I may try and get a longer solid line and remove the tubing. Every push on nipple for the soft host is zap strapped already. Reporting back this evening and thanks for the help - Trinker

Killbert · Post by **Killbert** » Wed Jun 21, 2017 5:15 pm

Trinker wrote:I've tightened up all the fittings. From the t junction on the boost line going to my IP I have about 50cm of heavy guage vacuum line going to the bulkhead, from there it switches to a hard line with brass pinch fittings that goes from the engine compartment up to the guage on my dash, Al nicely run out of sight with no crimps. I'll test drive it again today and see how it does, otherwise I may try and get a longer solid line and remove the tubing. Every push on nipple for the soft host is zap strapped already. Reporting back this evening and thanks for the help - Trinker

As stated earlier, it sounds like you may need to install a restriction or "orifice" into the feed line. They meter the airflow as to prevent such fluttering. Very common in Mercury gauges for motorcycle carburation sync..

Trinker · Post by **Trinker** » Wed Jun 21, 2017 9:21 pm

That's fair, its all tucked together tighlty and still flutters like crazy so I guess that's my next mini project. I wonder if anyone else has had to do such things on their own delis?

Post by **Growlerbearnz** » Thu Jun 22, 2017 3:11 pm

Mr Google says iEquus gauges flutter. (Paraphrasing here- the word "shitty" came up a lot). Killbert's idea might fix it. Otherwise I can recommend AutoMeter's Sport-Comp boost gauge (part number 3304).

https://www.youtube.com/watch?v=fmgToBSUjRI

Lapprentis · Post by **Lapprentis** » Fri Jun 23, 2017 7:24 am

Can someone teach the community how to read/operate (range, etc.) a properly installed Boost Gauge on a stock L300

Lapprentis

Trinker · Post by **Trinker** » Fri Jun 23, 2017 6:10 pm

Pretty simple isn't it? When under load (accelerating, climbing a hill or even driving on the highway) you should be boosting about 11-12 psi. Should never get much higher than that on a stock turbo with a standard tune. My aftermarket turbo spools up fast (needle come up fast) and levels out around 11 until climbing above 2500rpm at which point it has leveled to 12. If I'm under full load at 3000+ rpm and out the pedal to the floor I'll actually make 13.5 psi or so, but I never do that ever apart from testing the turbo. Right around 14.5psi my intake manifold pressure release valve opens, make a hiss under the driver seats, you loose power until pulling back on the throttle and spits a bit of black smoke, but nothing to dangerous. Only found that out by having the turbo too tuned up, for the most part of your levelling out (actuator opening) around 12psi that's nearly impossible.
I tuned in with a more precise vaccum/boost tester that isn't for mounting. I now know my boost guage reads 2psi low but you get what you pay for I guess. Damn thing still flickers too..

ajd · Post by **ajd** » Mon Sep 11, 2017 1:53 pm

I recently installed a boost gauge and had the same flickering, fluttering, or vibration problem. A very annoying sound. Thought I would share my solution for people looking in the future. The gauge I got wasn't even all that cheap, it's a VDO mechanical gauge that has a 15psi max. I tried all the supplied brass fittings that are suppose to be flow restrictors, and none worked (maybe the correct ones were not included in my package), it still made noise and vibrated. The internet is full of information on this, and I determined that it must be a flow restriction issue. Too much free air flow to the gauge from a potentially very unstable source (a high speed air compressor). hmm, seems like there should be a cheap and easy solution here..

This is one of probably many ways to make your own flow restriction: I had a small section (~20mm long) of 2mm tubing lying around (the outer diameter fits snugly into the inner diameter of existing tubing connecting turbo to gauge, you want something that you can assemble into your existing boost line, the little vacuum connectors sold at automotive stores would work great as well). I then trimmed just a sliver of fleece fabric (I think any porous fabric or shop rag would work) and stuffed it into the small section of tubing. I tried not to pack it in too tight otherwise you completely block the flow, you want to restrict it, not stop it entirely. Then a dab of super glue on either end to hold the fabric in place. careful not to clog the tube with the glue, just a little to hold the fabric to the inside of tube. A few tests by blowing into the tube like a straw left me confident that there was still some small amount of air flow but it definitely was restricted

I found a nice accessible place in the steering column where I had previously routed the boost line and cut and installed my little masterpiece there in-line. In theory it can be anywhere in-line between the gauge and turbo. Zip-tied the ends together, and it works! completely silent and smooth gauge needle now.

If you end up with too much restriction you could see a really slow response with your boost gauge, too little and you will continue to see vibration. Adjust the amount of fabric or how tightly it is packed in the tube if you don't get it right the first time.

This might fix your average cheap-o gauge flutter

YogaSlackerSam · Post by **YogaSlackerSam** » Wed Sep 13, 2017 9:36 pm

This seems like a good place to ask this.

How can I tell if the turbo is working? ( I have many more questions but ill keep this one simple and start my own thread tomorrow)

thanks in advance for the support.

Sam

Post by **Growlerbearnz** » Thu Sep 14, 2017 2:54 am

If the turbo wasn't doing anything you'd be lucky to make it past 60mph, and you'd have lots of black smoke out the exhaust. Though it's all relative to what you're used to- the engine is slow and smoky even when it's working properly.

A boost gauge is the real solution to knowing what's happening, and it's a lot cheaper than a new turbo!

Just don't buy an iEquus gauge. Apparently.

Trinker · Post by **Trinker** » Tue Oct 03, 2017 7:47 pm

I've been elbow deep in Apollo for the past couple of weeks and as I was wrapping up some more serious repairs decided to test AJD's fleece in tube flow restriction method and presto! No more gauge fluttering

Love it when something simple and easy works