4 guages for dash, which?
4 guages for dash, which?
I need to buy the guages for mock up build and was thinking of which are most necesary. Thought of: VDO's Speedo, electronic Tach Fuel Which of these two will be more usefull for a VW engine in a buggy? Oil pressure or Head temp thanks!
In my opinion, oil pressure, and temp are far more important. I wouldn`t limit yourself to 4 gauges. The tach can be mounted elsewhere. I think I would go with oil temp vs head temp. On my dash, I`m mounting oil pressure, oil temp, speedo, volts, and fuel. The tach will go opposite the steering column.
I have been building water -cooled street rods for the last ten years, and kinda fell out of the vw seen, but if I remember right, it is a probe that goes in between cylinder fins and measures temp. I personally never have trusted them, therfore never used one. I always went by my theory of my above post.
Give these guys a call. http://www.egauges.com/ They can hook you up with any type guages you like, and the proper senders for them. Talk to Don. He know`s his stuff about guages and VW engines. There are several ways to mount an oil temp sender, most require drilling the block. They have a new type sender that screws into the oil drain plug hole.
unless you use a vdo head temp on the spark plug base on no# 3 , it will not be a correct temp reading. not even close. I would skip it, I have almost every gauge on my buggy. but i am thinking of removing head temp. mine is not a vdo and it is mounted too far away from the true heat. oil temp and pressure are great .... I have fuel pressure, boost pressure, oil and head temp, oil pressure, tack, speedo and fuel level. i may add on a fuel mixture to see if it is running lean or rich... I only have this many just bacause i have 5k + in my engine and turbo.
Alexh, The CHT sensor from VDO goes between one of the spark plugs and the head. It's a thermocouple - it generates a small amount of electricity when it heats up. The hotter it gets, the more electricity it generates. The gauge measures this voltage and you see the head's temperature as a result. You need to keep the entire wiring harness that comes with the gauge intact and unmodified - it requires a certain resistance to give the proper reading. The gauge will also read slightly higher during cold weather and slightly lower during hot weather. The reason is the temperature you are seeing is the DIFFERENCE between the ring that goes under the spark plug and the end of its connector. The VDO CHT sender is calibrated to 70 degrees F. You are looking for a normal range of operating temperatures here. Every engine behaves differently, but it is important to keep the head temp below 400 degrees F. I checked the accuracy of my CHT with one of those laser thermometers. It showed that the gauge was pretty accurate, and it also confirmed that the spark plug area is one of the hottest spots on the head, by as much as 50 degrees hotter than the fins near the bottom! The areas around the exhaust ports get even hotter. All those vanes inside the cooling tins are designed to give a powerful blast of cooling air to the corners of the heads, where the exhaust stacks are. I like the CHT gauge because it tells me immediately when I am pushing the engine too hard. It takes the oil quite a bit longer to heat up than the heads, so an oil temp gauge will tell you when the engine got hot a few miles ago. You can tell when your oil is too hot if you have an oil pressure gauge. The rule of thumb on oil pressure with the air cooled VW is you should have at least 10 PSI for every 1,000 RPM. So if you're cruising along at 3,000 RPM, you should have at least 30 PSI on the oil gauge. If it dips below 30, your oil is too hot and has thinned out. On the highway, I fly by the CHT gauge. I watch it closely on the hills, ease off on the throttle or down shift when the gauge tells me to. With a stock engine and a loaded roof rack, speed limits are nothing more than a cruel joke. The near instantaneous reaction of the CHT guage enables me to drive through the desert fully loaded when the temperature is better than 95 degrees F. Doing this without the proper gauges could result in a cooked engine. I like your choices of gauges. If you have room for voltage you should have all the information you need. From left to right, I have CHT, Oil Pressure, Tach, Speedo, Fuel, and Volts: 
Alexh, You don't need a longer reach spark plug. I think you have to remove the washer from the spark plug when using the sender. I can't remember - does anyone know? Here's the one I have: http://www.sso-usa.com/performance/Inst ... inder.html You should be able to get one through your local VDO dealer or one of the online parts supply houses.
there was a good write up on the samba about this. it is best to get a dremel and grind a lip out on the head. remove just a little so the ring will fit along with the spark plug and ring. or you could use a head bold next to the no# 3 plug too. not as accurate but most people use it i guess. go here http://www.thesamba.com/vw/forum/viewtopic.php?t=129036&highlight=head+temp+spark+plug