Budget street legal rail (re)build (WARNING: pic heavy)

[GoMopar440]

I'm going to need all the help I can get to tune the carb(s) on my rail. On that note I will be using a PLX gen4 system with the DM6 multi gauge and the Bosch LSU 4.9 wide band A/F sensor. Here's a link to the same system I'll be setting up on the rail. http://www.ebay.com/itm/162014549301?_t ... EBIDX%3AIT This will be useful for any carburation (or EFI) setup, so it will be a great help for getting the tuning dialed in. A small turbo may be added later on, so that's another big reason needing to have a good A/F gauge.

The dual cannon exhaust that's on the rail now was originally bought just to get it through the state inspection (mufflers are required). The 4-1 megaphone exhaust that was on the rail when I got it was bent badly and didn't have any kind of baffling in it. Since then I have learned that the split style dual exhaust are mostly designed for looks, and aren't really a good match for the ACVW engines as far as performance goes. Also, living at 5K above sea level means I want to get all the HP out of my little 1600 engine that it has to offer up in this thin air. So a while back I got a bare quiet pipe ($17) to replace the bent megaphone for my Empi 4-1 exhaust and had a local shop weld a glass pack to it. The shop also braced the glass pack to the flange as requested so it wouldn't vibrate itself off the header. A chrome tip finished it off nicely.


I'll be putting the 4-1 exhaust, with the new pipe and muffler, back on the rail before I'm try to fire it up again. I was wondering if any one here has had experience with adding an A/F sensor to one of these types of exhausts. If so, where is the best place to weld the bung onto the header? I can figure out the rest with the instructions in the PLX kit, but I'll probably farm out the welding to the exhaust shop that did the glass pack install. Once the exhaust bung is welded up I'll sand blast it all and spray it with some Cerakote. From what I've read, that stuff is a lot tougher and more durable than the ceramic coating that comes on a lot of the cheap exhausts out on the market now.

[Piledriver]

Anywhere after the collector, usually as close as possible or even in the colletor... the cable should point up within 45 degrees of vertical, but note water (inside tube---condensed from exhaust gas) is an O2 sensors worst enemy, so i'd probably put it on an extended bung and try to avoid the possible spray coming up around that curve in the collector as she warms up.

Normally that curve would be horizontal and with the sensor on top is mostly out of the possible water spray.
On yours its a potential issue.

[GoMopar440]

Would just about an inch or two before the collector flange be ok? I'd like to keep it on the header itself, rather than on the QP pipe if possible. That way it wouldn't be as difficult if I were to redo the QP sometime later on. Somewhere around the red circle area like in this pic is where I was thinking. If that's a no-go then how about where the yellow circle is in the QP pipe? That second location would be easier to run the sensor wires away from the hot parts from the looks of it. I'm not sure about the effect of moisture from condensation in that part of the bend in the exhaust though.

[Leatherneck]

Yellow

[Piledriver]

Yellow and on the inside of the bend, or ~pointed toward the center of the engine.
Any condensate spray will likely head for the outside wall.

[GoMopar440]

Ok, looking over the PLX instructions again, which are surprisingly a bit vague in this area, they have two key points to meet for proper sensor placement. Link to PDF of the manual -> http://www.plxdevices.com/v/vspfiles/su ... _guide.pdf In the inline exhaust flow (coming or going) of the exhaust pipe the sensor should be pointing straight up vertical. By that rule alone, both the red and yellow locations would not work. For the second requirement, looking at the pipe from the side the sensor should be tilted back about 15* so the open tip does not point into the air flow. Another thing I wanted to try to do with the sensor placement was to place it somewhere that it would be protected by it's surroundings, not exposed. The yellow placement would leave the sensor hanging out to catch anything that might want to snag it if driving off road. If I swapped the yellow sensor location to the inside of the curve it would be more protected, and away from the most likely path of water in the exhaust. Placing it there would still violate rule number one by having the sensor sitting horizontally, which is a full 90* off of the recommended vertical placement. If I just rotate the bung further down in the inside of that curve than the sensor can meet those two installation requirements. I drew the new proposed bung location in blue this time. Since it's still in the curve at that point, I can mount it so the sensor is completely vertical from the front and from the side. It won't be on the header itself like I wanted it to (just for cosmetics really), but it meets the two more important alignment requirements of the sensor, as well as my protected area requirement. What do you guys think?

[Leatherneck]

Blue should work, away from collector and on top. Now if only Pile agrees lol

[Piledriver]

It could even go in the collector on an extended bung <45 degrees from vertical, on a short bit of tubing.

Blue looks fine, basically it just has to be able to drain if it catches a snout full of water, and well protected there.

[GoMopar440]

Hey guys and gals,

I would like to ask you to take a minute of your time and help me out with something that will be useful to quite a few people in the VW and Porsche community. I just sent an email to PLX Devices, the company I got my Air/Fuel Ratio Sensor Module and DM-6 Display Module from. I'm trying to convince them to consider adding a CHT Sensor Module kit to their product lineup. They already have a number of useful sensor modules that all work with their DM-6 all-in-one gauge. Currently this includes the following modules:
- Air/Fuel Ratio Sensor Module (Gen 4 Sensor Module with Bosch LSU4.9 wideband sensor)
- Exhaust Gas Temp Sensor Module
- Vacuum/Boost Sensor Module
- Fluid Temp Sensor Module (works with any fluid)
- Air Intake Temp Sensor Module
- Fluid Pressure Sensor Module (not for fuel - for use with oil only)

If they added a CHT to their lineup, that would make their DM-6 a TRUE all-in-one gauge for those of us with an air cooled engine. I'm going to post this same message over on The Samba in the Performance Engine sub forum to try to get the word out to as many VW people as I can. If you know of any other VW or Porsche, or any other forum that could use a CHT gauge, that might help with this email campaign please feel free to post a link to this thread, if that's allowed on those forums.

Below is a copy of the email I sent off to PLX Devices earlier today. Feel free to copy and past the pertinent parts of it if you want, but a quick note asking them to consider adding a CHT Sensor Module to their product lineup would be just as good. Even if you don't plan on purchasing one of these CHT modules in the near future, it would be a big help to all our fellow enthusiasts in the air cooled VW and Porsche community that are looking to add that functionality to their vehicles.

To:
Richard Ewing
Customer Experience Mgr.
PLX Devices

I will be using the DM-6 in an air cooled VW powered sand rail and my current dashboard is a very small aluminum box. I have just enough room for a speedometer, tachometer and one DM-6, as well as a key switch and a few LED lights. I would think with all the air cooled VW and Porsche powered vehicles still on the roads today, that a Cylinder Head Temp Sensor Module would have an immediate market if you chose to produce one. Cylinder head temperatures are one of the most important things to keep tabs on with air cooled engines. CHT, EGT and Boost are the top three need to know pieces of info to monitor when adding a turbo, which a lot of VW and Porsche enthusiasts have been doing for a very long time, and are still doing quite often to this day. Check on a few of the top VW enthusiast forums and you will find entire sections of the forums dedicated to the topic of turbo charging. The Samba is most likely the largest VW forum today with over 345,000+ members worldwide, and Shop Talk Forums with almost 27,000 very active members are among the top two VW web forums that first come to mind. If you would like to get direct market feedback on whether or not a CHT Sensor Module kit would be a viable product, these two sources would make for a very large (and free) focus group. Porsche forums would be another option for feedback as well, but I don't own a Porsche so I don't frequent any of those forums.

I've said all this to hopefully convince you that there is a huge market for this potential addition to your product lineup. From what I've seen with the products you currently offer, you clearly already have the capabilities, knowledge and production facilities to easily create a new Sensor Module to read a CHT sensor. In my humble opinion it would be a sorely needed addition to your already impressive product lineup and should be able to hold it's own right out of the gate.

Thank you for your time and consideration,

Here is a link to the PLX email contact web form on their website.
http://www.plxdevices.com/Contact-PLX-s/144.htm

I'm hoping that with enough encouragement PLX Devices will get the definate impression that it would be worth their time and effort to produce A CHT Sensor Module kit. Please pass the word. Thanks everyone!

[GoMopar440]

I got another reply back from Richard at PLX today. He quite flatly stated that they have no interest in making a CHT sensor module now or in the future. Without any help with this email campaign idea I doubt they'll change their minds.

In that case I'm going to step back and reconsider my original idea of using the DM-6 to monitor everything on the engine. I know there are other companies out there that do make all in one gauges that will monitor and display all the info I want to keep tabs on. More than a few avionics equipment vendors come to mind.

[GoMopar440]

I received some good feedback over on TOS that seemed like it would be relevant so I copied and pasted some of it here.

TOS member Stripped66 wrote:
Use the EGT module with K-type thermocouples under the spark plugs or in the head under the chamber.

PLX already makes what you need. Read the product description.

I saw that and thought the same thing. In my first email to PLX I asked them to verify that I could use their EGT Sensor Module with a CHT thermocouple. This was their reply.

"I think the problem is that your Cylinder Head Temp(CHT) may not work with our devices. Buying our devices is like buying Apple products. Our devices don't work well with other manufacturer's products. You can try it, it's just that it might not work.

Respectfully,
Richard Ewing
Customer Experience Mgr.
PLX Devices"

That led me to asking them in a follow up email if they would make a CHT Sensor Module. I posted the majority of that email in my first post in this thread. This was their reply to that query.

"No we don't make a CHT sensor and we're not in the market to do so in the future. I'm sorry that we couldn't accommodate your situation. Thanks for considering PLX Devices.

Respectfully,
Richard Ewing
Customer Experience Mgr.
PLX Devices"

Since I already have the Air/Fuel Sensor and Gauge combo kit Combo I may as well do like Stripped66 suggested and see if I can get a CHT K type thermocouple to work with a PLX EGT Sensor Module. The only down side to that is if it doesn't work, I will have invested deeper into the PLX system and be that much further behind if I wanted to try a different type of all in one gauge system in it's place.

TOS member PS2375 wrote:
Check with this site, I've used his OG WB kit for years with no issues. And he has a multi-sensor dash unit.
http://www.14point7.com/

The 14point7 website has some nice stuff on there that might just work. I'd have to buy a tablet (don't own one currently) to be able to display everything on one display though. They offer single purpose 52mm displays for Air/Fuel Ratio and EGT, but not for any of the other sensor outputs that I could find.

TOS member esde wrote:
While I do appreciate the all in one gauges for some things, some info I want plainly displayed, on its own gauge. When driving I glance at the gauges, and get accustomed to what the safe ranges are for the needles, and when one is out of place I quickly spot it. No way could I scroll through menu's or a whole screen of info to look at data. I won't look at my phone while driving either, I get too distracted.

Stripped66 seems to have hit the answer, I wonder if you could hack the gauge to change egt to cht? I have the same plx and love it as the gauge face is so small and flat. I glued a magnet to the back and stick it to the dash when I need it, otherwise it gets stashed in the glove box.

I usually do the same as far as scanning my gauges while driving. In this case on my rail I'm looking at the DM-6 display as being more of a tuning tool. I can swap the all in one display from sensor to sensor to keep an eye on different things, but for this vehicle I plan on mostly sticking with factory style idiot light system. The current plan is to use a Speedhut 3&3/8" GPS speedometer with turn signal and high beam indicators built in, with either a 2&5/8" or 2&1/16" Tach and the one 52mm (2&1/16") DM-6 gauge. In between the gauges I'll leave space for the Oil and Alt idiot lights and a standard key switch as well. I'm just trying to use the small dash space I have as efficiently as possible.

[GoMopar440]

Getting back a little closer to being on topic...

Today while poking around the local JY I located a few fender mounted grey TFI ignition modules (Ford) with the big finned aluminum heat sink mounts. I'll be picking up three of them (two for spares) on payday for less than the cost of one new TFI module without the heat sink mount.

I also asked the guy that runs the yard to see if he can find any factory turbos on something with a 2.5l or smaller engine. I'm really hoping he does, because he said he'd sell them to me for $25 a piece if I pull them myself. I have no problem with that, especially at that price.

For some reason I've been hearing the same song rolling around in the back of my head all day today. Johnny Cash's "One Piece at a Time".
https://www.youtube.com/watch?v=rWHniL8MyMM

[GoMopar440]

I have a spare exhaust Y pipe for my truck hanging up in the barn. I've been saving it for the large oval flange on it that sits right before the catalytic converter. I didn't need any of the rest of the Y pipe, so I cut one of the O2 bungs off of it to use on my 4-1 header. I got most of the weld cut away with the cut off wheel while leaving the outside part round enough for the lathe chuck to hold it true. I cut away the rest of the weld on the lathe to reveal the original 7/8" diameter shoulder underneath. Given that this bung is going to be installed into a bend in the pipe, I had to take that shoulder up a bit further so it would be able to sit deep enough to have no gaps between it and the pipe when installed. I also deburred the threads and all the inner and outer edges with files and sand paper while it was still chucked up in the lathe.

On the pipe itself, I didn't have any way to make the bung hole (snicker) sit perfectly straight up at 90* like the instructions called for. This was due to the bend being in the way of the drill and the uni-bit. So I compromised and tilted the hole towards the front of the vehicle about 10*, which was just far enough to get the clearance needed to drill the hole. The hole was drilled as close as I could get it to where I drew the blue circle in the last pic I posted. I used a file to debur the edge and remove the paint around the hole so it would be clean for welding. A light tap with the hammer and the O2 bung was seated snugly into the hole without any air gaps anywhere. All that is left now is to have the bung welded into the pipe tomorrow.



For now I'll just be using regular high temp header paint on the header after O2 bung is welded and it's all sand blasted. I still to need add two bungs for EGT sensors in place of the intake heat risers on cylinders 2 and 4 later on. Until I can get the other HPMX carb to complete the dual carb setup, I'll just be keeping the single 34 PICT-3 setup in place until then. As a result, those heat risers will be staying on the header for a little while longer. Once the dual carb setup is ready I'll get rid of them and have the EGT bungs welded in their place. Then it will all get sand blasted again to remove the header paint and prep it for the final finish which will be Cerakote.

[GoMopar440]

I realigned the O2 bung before bringing it in to get welded today. I moved it around until the O2 sensor would have the needed 15* of layback in relation to the direction of airflow. This should help keep condensation from getting shoved up into it.



It's pretty far from vertical when looking at it from the side though. It's a compromise I'm willing to accept given the limited clearance available inside that tight curve.


I also picked up a few Ford remote mounted TFI ignition modules from the JY today. I'll be wiring one of them in to the rail, and the other two are for spares. The original points will act as the trigger and the TFI unit will act like a switching relay for the coil. When setup this way, the TFI module takes the heavy voltage load off of the points. It should extend the life of the points by quite a lot and allow for a higher voltage coil to be used with it.


I also picked up this four post coil today, but I'm not ready to use it just yet. It will be useful for some different ideas I want to try with the ignition system later on.

[GoMopar440]

Between doctors appointments and chasing down the parts I need to fix the Jeep, I haven't been able to get anything done on this project for the last week. After I got home from my latest appointment this afternoon/evening, I made some time to get a little bit done on it.

I have the exhaust all welded up now, so I started with sand blasting the J tubes. They had been mostly blasted before so they just needed a little touch up in a few spots. The HF blaster wasn't cooperating with me so I had to stop and work on it again. I tried all the regular quick fixes and nothing was working this time. I ended up having to disassemble the gun and remove a few lodged pieces of metal that looked like they were from the manufacturing process. That did the trick and the gun was now working as good as it ever was. Once both J tubes were done, I decided to address the flaws inside both ends of the pipes. The welds on the flange ends were encroaching into the bore almost 1/4" in some places. At the opposite ends of the tubes there was a sharp burr most of the way around the inside edge. I used a grinding stone in my Dremel to work out the majority of the imperfections and then switched to a small 80 grit flap wheel to smooth it all out. After that I went over the outsides of both pipes with some 00 steel wool just to get the surface texture a bit more smoothed out. Lastly I painted each tube with some silver Rustoleum 2000* high heat header paint and hung them out to dry. I didn't bring the camera out today with all the fine dust floating around the air in the barn. I'll take some pics tomorrow after teh paint is dry and the dust has had a chance to settle down.

Next up will be the main part of the 4-1 header. However, I most likely won't be able to get to it until this weekend since I'll be fixing the Jeep brakes tomorrow. The header needs to be completely blasted and painted like the J tubes. I'll address any imperfections as I come across them. After a casual first glance, it doesn't look like it will need near as much work as the J tubes did. However it has a lot more rust, and a bunch of overspray splotches from the PO's olive drab rattle crap paint job.

After that's done, the QP muffler section will get done last. It's not rusty at all, but it has that black shipping paint on the pipe and flange that needs to be removed before I can repaint it with the high heat paint. It would suck to get the glass pack filled with that aluminum oxide grit, and I also don't want to screw up the chrome tip, so the QP will not be getting sand blasted. The plan is to just use a wire wheel to get the black paint off, fix any remaining imperfections and then hit it with the high heat paint.