here are some tips on installing a boost gauge

[david.avery]

Hi everyone

I recently installed a NH speedo boost gauge with their brake booster adapter kit. Before I installed, I couldn't find any instructions (didn't come with any) and there were none on PP or rennlist, so I thught I'd give back a bit to my community and post it here.

First off, the adapter is very very flimsy. It has a very small 1/4" plastic hose fitting on it, to which NH speedo put a piece of 1/4 fuel line, then clamped a piece of 5/16 fuel line over. This thing can snap if you look at it too hard. I broke mine during install, well more on that later.

Here ya go:

1) Remove clock - just pull on it with your manly fingers. A slight twisting motion will get it out. Disconnect the small light, and the brown and black leads. I taped them together to keep them from getting pulled back into the hole.
2) Remove fiberboard backing cover from your trunk - you don't need to remove all the bolts, two are slotted - just loosen them, it will slide off.
3) Locate the 5" long hose in a U shape that connects the hard line welded to the body to a fitting that goes to the back of the brake booster. Loosen the clamp on the body, slide the clamp up and pop it off the barb.
4) Now, you need manly fingers of steel to wrench the check valve from the booster. Follow the hose to the check valve, it's pressed into a rubber socket in the booster itself. I used a "squeeze plier spreader" which is like a circlip plier, it pushes outward when you squeeze it. Prepare for lots of cuts, there are lots of little sharp things in there. I got it out by rotating, and pulling with all I had.
5) snake the hose up under the brake hard lines, and try to aim for the clock hole. I used an electrician's snake to get this right. More swearing here, while you sit in your trunk.
6) Put the hose from the check valve on the new check valve but don't tighten it. Keep the clamp so you can get to it while it's affixed to the booster.
7) Slowly and carefully guide the wide part of the check valve into the fitting on the brake booster. This was very very difficult. Took me almost a half hour - 45 minutes. The hose that goes to the gauge will prevent it from fitting in there square. More cuts and swearing will happen here. It also takes quite a bit of force to get it into the booster. This is when I broke the first one. A tip, a little moisture (I licked my finger, gross I know but I was trapped bleeding in the hood of my car) makes it slip in much easier than going dry
8) Back into the cabin, I cut the lamp off (blue/blk) with enough room for it to be re-attached, and stuck the bulb back in the clock. I then put a piece of shrink tubing over the wires, and soldered on a 3" piece of black wire with a push on spade connector on it (goes to the lamp).
9) Shrink wrap and tape the black wire (was +12vDC to the clock) and re-attached the brown wire to the lamp on the clock.
10) loosen the clamp and pull the hose adapter apart, and remove the barbed end from the hose. Fasten this into the boost gauge brass junction. Hold the brass block with a wrench or you can destroy the boost gauge - it's somewhat fragile. Push the hose back on the barb, align it (make the gauge sit upright) and tighten the clamp.
11) Put the rubber surround on the gauge and push it into the dash.
12) Test it out!
12) Finish putting the trunk back together.

After how much I spent on the gauge and install kit, I was disappointed that NH speedo would not just send me a replacement check valve. By the time it was shipped to me, it was close to $40.00 more (though they had made an error, and promise me a $10 credit)

Anyhow, hope this helps someone, may it save you some money and a few slashes on the hands

[david.avery]

Thanks for moving it Noah

[BlkBird]

Interesting. I am thinking of doing this myself but I may let the shop handle it. Have you installed any other auxillary gauges such as a voltmeter, A/F gauge or Exhaust temp gauge?

[david.avery]

Hey Blkbird

No, no other gauges yet, I would like a voltmeter and EGT soon though.

[BlkBird]

David,

I'm thinking of replacing the clock with a more accurate boost gauge. It was also suggested that a voltmeter and an A/F gauge would be useful to have.

So that brought the need to search the board looking for ingenious ways to install a voltmeter, A/F and either an Exhaust temp gauge or a replacement quartz clock. Some look to have mounted added gauges in place of the ashtray (which works since I don't smoke). Or replace the vent controls - an ingenious idea but perhaps overdoing it for a street car. Or mount the gauges in the center console (mine is already full with A/C control, fan, hazard and an XM radio unit).

Let's face it. Our cars don't have a lot of space left empty for us to use, so there has to be a trade-off if you want to make changes. Where do you plan to mount the two custom gauges when you do add them?

[david.avery]

Probably the console, using an alum plate over the storage area... I know 9x auto makes some bolt-ons.

[Lukesportsman]

On a turbo install like this, should a EGT be installed in each collector, in front of the turbo or after the turbo? I know that in a race situation we often install EGT's in each primary to precisely tune each cylinder. On the street, I think were more interested in trends and the dreaded melted piston.

So how are guys doing for a street car?

[david.avery]

Good question Luke, you may want to make this a seperate post to get more play.

[BlkBird]

Prototype bracket installation. I'm not sure if I should stick with this type or just go to a flat piece of billet and thereby avoid trying to "upholster" the bracket. Billet might look too utilitarian for a street car. On the other hand it is near impossible to match the look of the stock dash.

Thoughts?

[tsuter]

I'm too cheap to spring for an overpriced 3" boost gauge when a standard size VDO is $25.00 and my car is too nice for a ghetto 2-1/4" gauge in a 3" clock hole...... so I went looooow. How loooow can you gooooo?

[RarlyL8]

If a boost gauge is going to be useful it has to be close to your line of sight. In a fast action boosted car this would be as close to the tach as possible. The clock hole is a good spot. You don't normally need a clock close to your line of sight. I put my boost gauge in the clock hole and moved the clock down to the console.

The brake booster "kit" is a joke. I have one that came with the overpriced clock boost gauge. I'll sell it cheap if someone wants it (they charged me $70 for it).
The only place to get an accurate boost reading is in the intake of your engine - not in the brake system. I've yet to see a race car with a boost sensor mounted off the brakes.

[BlkBird]

Version 2 of the gauge bracket. I used the handle of the ashtray to make a more uniform finish but I have to admit I'm still not ecstatic. Trouble is there just are not that many places to add extra gauges to a 911/930.

You can also see my clock replacement boost gauge.