924Board.org

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Starting to think about what I'm going to need from an instrumentation perspective. Here's what I've identified as desirable cockpit inputs:
Gauges
- Speedometer
- Odometer
- Tachometer
- Voltmeter
- Ammeter
- Vac / Boost
- Wideband AFR
- Coolant Temp (at head)
- Coolant Temp (at radiator)
- Oil Pressure
- Oil Temp
- Trans Oil Temp
- Fuel Pressure
- Fuel Level
- Ex Gas Temp
- Intake Air Temp

Warning Indicators
- Shift light(s)
- Turn indicator
- Bright light
- Low brake fluid
- Low oil pressure
- Low fuel level
- Low battery

Primary Display
Since I'm locked into a wheel speed sensor due to elimination of the mechanical speedo-based spindles, I have to use an electronic speedometer. I also want to be able to get into data logging eventually, although not for the stage one build. For these two primary reasons, I'm leaning heavily toward a digital dash and data logger setup, a similar setup that Vaughan and Chris use in their cars. It's the Dash2 from Race Technologies.

This unit is very compact, and takes care of all of the standard instrumentation in the stock 924 primary 3-gauge cluster: speedometer, odometer, tachometer, fuel level, turn indicators, hi beam / lo beam, brake warning, rear fog indicator, alternator output, configurable multiple shift lights, plus four add'l analog channels that can be used for things like digital display of water & oil temps.

It is a modular system as well, so when I'm ready to start doing some serious tracking and data logging, I can add on the DL1 component and be ready to go. Here's a photo of the Dash-2:

Auxiliary Gauges
This is where it gets a little less clear for me. I really like the PLX Devices concept, particular with regard to integrating with my ECU; and I'm pretty much sold on using them for at least the wideband AFR. At the same time, I really dislike having mismatched instrumentation. The quandary is that if I go with the full PLX devices lineup, it gets very spendy, very fast, and on top of that, I will still need to source a voltmeter, ammeter, oil pressure gauge, and fuel pressure gauge (none of which are in their lineup). So what I'm currently considering is the PLX Devices Wideband AFR, and then doing everything else in VDO Cockpit Black standard analog gauges.

Dash
I am also still undecided on what to do about the dash. I can get a fiberglass dash from a variety of sources for ~$250. I'm currently leaning toward the one from GT Racing simply because I like the angled orientation of their race dash. The other alternative would be to fabricate something completely custom from lightweight aluminum. My concern with that approach is dealing with glare. Sure, alu can be painted, but I don't want it getting scratched up either. If I go the fabrication route, I'll probably just cut the alu to conform to the curve of the windshield, and then bend a 90° angle on a break to form the face. It will be spartan, but that's not a bad thing for my overall design aesthetic on this project.

Have I missed any important instrumentation? Are there other alternatives I should consider? Comments, observations, suggestions regarding the dash?
_________________
erstwhile owner of just about every 924 variant ever made

Fifty50Plus · Posted: Fri May 15, 2009 9:35 am Post subject:

Dan - Funny story...
Some years ago I was assessing Pro driving schools for SCCA. I was asked to go to Road Atlanta and participate in the Panoz school to see if it qualified as a school that would be able to award SCCA racing licenses. The school was very well run with high quality instructors and we were driving the Panoz GT-2 car with the Ford V-8. Part of my briefings by the instructors and crew chiefs included the digital dash display and how to toggle through all the different readings. There were no other instruments on the dash besides this display. As I recall, it gave me more readings than I ever could imagine needing in my own race car but I dutifully toggled through them as I went down the back straight at Road Atlanta. Each session I made note of the different readings but kept being annoyed by one stating: Brakes - Cold. Now this Panoz had giant brakes without a booster so you really had to press the pedal to slow down. Each session I kept going deeper and pushing harder but the result was always; Brakes - Cold. I'm starting to get out of control under braking but can't seem to warm them up.
I finally complained to one of the instructors that I didn't know how to take full advantage of the brakes because I couldn't get any heat into them; the reading told me the brakes were still cold. He and the crew chief started laughing at me because he said it was an English dash system and there was no sensor connected to the brakes. Cold apparently meant no continuity.
Make sure you fully understand what you need to know to drive the car. Too much info can get you distracted.
In my race cars, I have RPM, temps and pressure. My data guy captures another dozen readings along with G forces on an on-board computer transmits it back to the pits and interprets it. If he thinks I need to know something, they get on the radio and yell at me. Bliss!
Chuck

huckster · Joined: 22 Dec 2006 Posts: 115 Location: Burnaby B.C.

The digital gauge looks nice and I can see ther advantage but sounds complicated. I prefer the analog gauges easy to read and are what I understand.
_________________
77.5 project car have never driven. burgundy
79 parts car sea foam. blue new clutch and shifter bushings
79 driver yellow new shocks water pump shifter bushings
96 ford escort sw

924RACR · Posted: Fri May 15, 2009 9:45 pm Post subject:

LOL! Nice one, Chuck!

Telemetry would be cool, haven't progressed to that yet... of course I'm the only driver on our team running a radio yet either...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Chuck, I hear ya! When I track the car, I have no intent of trying to monitor the digital dash while driving, other than for RPM and shift lights! I'm sure I'll be holding on for dear life!

Also, I much prefer an analog look to the digital dash, but I have not been able to find an analog style speedometer/tachometer combination that provides a clean and easy upgrade path to data logging.

If I go with standard VDO electronic speedometer and tachometer, I'm already at nearly half the cost of the Dash-2, but with no direct path to data logging. The one thing that I REALLY like about the Dash-2 is how it can be used as a learning tool when combined with the DL1. The data logging features allow you to plot data points relative to track position. So the advanced features of this unit are really more to be used off-track than while driving.
_________________
erstwhile owner of just about every 924 variant ever made

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Quick mockup, pretty much to-scale (although I'm not sure the center console portion is oriented in exactly the right location relative to the steering wheel).

This is the Dash-2 unit, a Momo Corse 330mm steering wheel, the PLX Devices AFR, EGT, and IAT gauges, and everything else from VDO Vision series.
_________________
erstwhile owner of just about every 924 variant ever made

morghen · Joined: 21 Jan 2005 Posts: 9102 Location: Romania

do you realy need that big lcd under your nose?
i would never put stuff like that in my porsche.
_________________
Supercharger and EFI kits
https://www.the924.com

Cedric · Joined: 27 Aug 2004 Posts: 2822 Location: Sweden

You could also go with analogue meters and a smaller dash, like the dash3. The dl1 is a real gem, with the input channels everything you want to do can be done. You dont wanna miss out on that one if you are building a car which nevertheless will cost you lots of $.
_________________
1980 924 Turbo
www.instagram.com/garagecedric/

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

I just fixed the steering wheel...I screwed up the scale on the original mockup...the Dash-2 is really not that big. It literally fits in the palm of your hand.

This car is being built as a track car, not a replica. Balancing form and function is always a challenge. If I could find an analog gauge that did what the Dash-2 did, I would use it. But so far, the Dash-2 is the best bang-for-the-buck display that provides the features I want at a sub-$1000 price point. I considered using a Dash-3 with conventional analog electronic speedometer and tachometer, but that approach will cost about $300 more, and it will take up more space.

I would LOVE to find a conventional-looking analog style display that had the upgrade path to full data logging. If anyone knows of such an item, let me know!
_________________
erstwhile owner of just about every 924 variant ever made

tuurbo · Posted: Sat May 16, 2009 7:27 am Post subject:

Hey Dan I'd like to just reiterate a point already made: The first dash mockup looks like way too much information. But you're working that out.

I think Porsche did a good job with the standard gauges around the driver. Easy to read and easy on the eyes (form) facilitates function with those gauges I think. The others look fine to me.

But it's not an easy question on how to set up the gauges and so on with a car intended to serve more than one function.

Why not put that complicated digital and LED thing off to the side, like some guys mount a Tom Tom or GPS - just mount it to the windshield when you need it and remove it when you don't?

This way you keep the best of Porsche decisionmaking, have your own gauge clusters in front of the shifter, and the complicated gizmo only for when you need it.
_________________
1980 924 turbo, MSD, Meth. Inj, otherwise stock.

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Some good thoughts there, tuurbo. The challenge is I need a tach and a speedo since this car will be doing double duty as a road going track toy. I think what merits some thought is combining some of your concepts with what Cédric said about using something like the Dash-3 instead of the Dash-2...maybe there are other such alternatives that aren't as spendy.

One thing I will say is that Vaughan and Chris both have a previous version of the Dash-2 in their cars, so part of my current leaning is based on their recommendations and having seen them in action.

I've got plenty of time to settle on a solution, so I'm sure there will be several more iterations. All of the feedback is very helpful to me, and part of the purpose of floating these mockups and ideas is to help me plan far enough ahead so I can manage my budget. Keep 'em coming!
_________________
erstwhile owner of just about every 924 variant ever made

Fifty50Plus · Posted: Sat May 16, 2009 10:42 am Post subject:

Also, orient all your analog guages so that straight up is the ideal reading. That way a quick eyeball scan tells you all is well and you don't have to do any pesky thinking.
Chuck

tuurbo · Posted: Sat May 16, 2009 1:22 pm Post subject:

I think by mistake there's a second oil gauge that shouldn't be there. There's one immediately to the right of the steering wheel, and another in the lower right corner under the digital gauge that reads '48'. Just a cut and paste thing probably, or vision problems on my part.

It's hard to read other gauges in the array. But I was looking for cylinder head temperature and was wondering "Where the heck is it?"

I personally would want cylinder head temperature on our cars. Those heads get so hot, they're the cause of a lot of problems specific to the 924 turbo. So that'd be my pick for one of those gauges that would be right up front in my field of vision. I'd pick a temperature that is ideal operating temperature and I'd point it straight up like Chuck suggests, and have it there like an idiot light. I can't see if you've already got that one.

I think too there's one too many gauges for electrical. Am I reading it right that there's one for Amps and one for Volts? Cause that's what I mean. I'd just have one.
_________________
1980 924 turbo, MSD, Meth. Inj, otherwise stock.

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

The second oil temp gauge is for the transmission oil. I am planning to run an oil cooler for the gearbox, and a lot of the race car dashes I've studied have oil temp gauge for trans.

The gauges are from left to right and top to bottom:
Water Temp
Boost
Dash-2 (which can have up to 4 add'l digital "gauge" readouts)
Oil Pressure
Oil Temp
Switch bank
Wideband AFR
Exhaust Gas Temp
Intake Air Temp
Voltmeter
Ammeter
Transmission Oil Temp

The ammeter might be overkill as may be the intake air temp. Cylinder head temp is an idea, although I have no idea what a "good" reading would be!

The nice thing about the Dash-2 is that the four add'l inputs can be used to setup multiple sensors for the same readings. bass gt had suggested a CLT sensor at both ends of the head to monitor how well the improved corssover pipe setup is working. Not something you would monitor in real time, but being able to data log it and plot it against your course could certainly yield some interesting data regarding how the car is performing under different circumstances. Same with oil temp, one at the oil filter adapter and one at the dry sump reservoir to monitor differential.
_________________
erstwhile owner of just about every 924 variant ever made

924RACR · Posted: Sat May 16, 2009 10:21 pm Post subject:

Just a couple things. The dashes Chris and I are using in the racecars are actually made by AIM, not Race Technology, so are not related to the Dash-2.

Also, since the Dash2 is a datalogger, you should plan your config to use it to display anything you might want logged on-track. Plus then you can eliminate those analog gauges.

Based on your list, I'd think that oil temp/pressure, water temp, and boost would be appropriate, unless you might prefer actually to log the AFR instead. Speaking of which - I'd instrument to log AFR instead of EGTs, and not both. Likewise CHT would be an unnecessary duplication - usually only used for aircooled engines.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype