I'm installing a steering column Pettite turbo gauge on a stock 1993. The instructions say drill a 1/4" hole below the clutch master cylinder or between the steering column and gas pedal. There is not a lot of room under the dash for drilling...and the instructions are not specific (measurements from some fixed point)...I don't want to make a bone head mistake. Has anyone performed this mod. and can you give me some advice as to EXACTLY where the hole for the boost line should go?

Is there a better way to route the boost line than what the instructions from Pettite suggest?

Pettite is closed until Monday and I searched but got nothing on this question.


Thanks,

 

I've done it many times Bill, it's easy. You will need a grommet for the hole after you are done of course. I always use a drill with a long bit. Look at the firewall around the steering column for the best spot. Now go look from inside the engine compartment. Look several times to get the best spot for the nylon tube to pass thru. You will be drilling thru 1/4" of the black insulation then 18 gauge steel behind that. So look, plot, and effect the drilling. This is not a major exercise and there is no need for photos, measurements or hand holding.


Later

 

Thanks Tom...now, I don't want to seem like an ungrateful peckerhead...but I can see 6 or more places where I could punch a 1/4" hole. I just don't want to be wishing I had punched the hole somewhere else when I'm done...so I'm looking for a little more direct advice as to the best location for the hole and maybe why...from other folks who have run this path before.

I understand it is not rocket science...but sometimes it's the simple looking things that can bite you in the ****.

 

There is absolutely no need to drill a hole in the firewall:

 

Ah, I was pondering that route but thought I might have to drill at the bundle hole just left of the hood release to get through to the front fender area. A little more work to remove the tire and wheel well but worth it for me to not punch a new hole in the chassis. I'll definitely take another look at that to see if it works...did you run your boost line through there "moconnor" or are you just teasing me?

 

Yup - I run a whole pile o' things through there, including a battery cable for a relocation.

 

Great, that'll be my after breakfast task tomorrow...then....once the turbo gauge is working...I'll see if there is more work to be done!

Hope to return the favor some day...if you ever need your Diagnostic Module (air bag) rebuilt or speedo board worked on...let me know.

 

For an electrical wire, I would agree. However, for a mechanic boost gauge which needs a vacuum line attached; I would recommend drilling the firewall as you want the shortest line possible for better readings. If drilling is not an option, punch a hole into the grommet for the steering column:

http://www.fd3s.net/boost_gauge_install.html

 

^^ That is what I did. I just made a small slit in the steering grommet and ran the boost line through there. I have used the fender well path for my battery relocation as well.

 

moconnor...thanks again. Routed the boost gauge line through the chassis/fender access...it was easy and the task is complete. Time to go play (in zoom zoom of course!).

 

Wow. Kind of neat having a T-gauge. Damn near ran into half a dozen cars while staring at it. All the boost numbers are right at the book value's...life is good.

Thanks again for all the input guys.

 

For this application the measurement inaccuracy due to the extra 30" of hose would be below the noise floor. It is easy to see with a MityVac and various lengths of hose that the difference between 10" and 10' of hose would not be resolvable on most analogue boost gauges. As for reaction time, boost gauges already need a dampening pill to filter out compression pulses so it should also not be an issue.

 

To each his own....but drilling/grommeting the firewall is sooooooeasy - well I cannot see doing it any other way. Unless you like jacking and taking fender liners apart.


Later

 

I routed my vacuum hose through the hole for the hood release cable, I had to remove the rubber plug for the cable though.

 

My other consideration was my 7 is bone stock as purchased except for tires (2nd set, OEM's dry rotted), battery and sparky plugs. I did not want to punch a hole, however small, in the body unless absolutely necessary. And it wasn't.

It took maybe 15 minutes to remove the tire and 8 wheel well fasteners (last half of well) to get to the plug. Another 15' to pulled the body plug, used a 3/16" leather hole punch and hammer to make a nice professional hole for the boost tube, removed the pre-cut 1/4" plug from the sound deadening, wire fished the tube from the cockpit to the fender and then through the engine cable access hole to the manifold nipple. 15 minutes to put the wheel well and tire back on.

If I want to put the car back into its original purchased configuration...with no extra holes (except for the body plug and a dab of black RTV will remedy that)...I can do it in a matter of minutes without removing the tire/well. No friggin' extra holes. That was important to me. What can I say? I'm ****. Sometimes the right way, ain't the easy way.