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captnbilly Samba Member
Joined: April 21, 2006 Posts: 195 Location: tampa bay
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Posted: Wed Nov 01, 2006 8:31 am Post subject: The future of T2 F.I. |
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A samba search of "fuel injection" or "carburetion" gives some idea of the interest and problems with T2 engine management. Many abandon their F.I. for carbs even tho it is undisputed that F.I. is the far superior engine management system. Scarcity of parts and rediculas prices are certainly part of the problem. Twenty years ago F.I. was a black art for most of us. In todays techno savy environment cheap, custom and reliable F.I. is literally at your finger tips. A "grease roots" movement styled MEGASQUIRT puts engine management with F.I. in the shade tree mechanics hands. As a tease here's a quote off the MEGASQUIRT forum site regarding a T2 L-Jetronic conversion:
"Megasquirt uses the manifold absolute pressure (MAP) instead of the Bosch Air Flow meter. This is simply a vacuum hose connection from the manifold to the Megasquirt ECU.
You will have everything else you need from the L-Jetronic except an air temperature sensor (that is usually in the Air Flow meter). So you simply add that somewhere at the intake. You can initially run the megasquirt with the Bosch system in place and switch between them. Once the megasquirt works to your satisfaction you can remove the Air flow meter and the Bosch ECU.
I recommend you go with the MS 1 v3.0 so you can take advantage of some of the features and updates."
The full discussion and more is at:
http://www.msefi.com/viewtopic.php?t=14996
You can also check one owner's conversion of his BayWindow at:
http://tbone2091.tripod.com/megasquirt/
tbone's set up is "developmental" and an actual running system would take up less room than the original L-Jet (no AFM). He gives you the perimeters so the hard part is done and for less $$ than a carb conversion. I have no relation to these folks, just been watching the whole trend in cars, bikes, planes toward "garage mechanic" engineered F.I. Once you get over the "AHA" part its a no brainer. For my money this technology has arrived and is accessable to those who care about more than a pretty outside. Later, Bill |
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casey79westfalia Samba Member
Joined: May 22, 2003 Posts: 1716 Location: Baltimore
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Posted: Wed Nov 01, 2006 8:51 am Post subject: |
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I am very interested in this setup. My bus runs very well now with the stock ljet but I am always looking to improve. I think most importantly this setup can be used when going away from the stock setup!! _________________ 66 Westfalia
87 Westfalia Syncro "Phoenix"
88 Double Cab
76 Porsche 914
2014 Audi Q7
2010 Tdi Sportwagen
Currently looking for 62 Double Cab, 66 Westfalia Parts!
(Rear seat and pedestal, bumpers, mirrors)
http://www.baycountrymotors.com
My 87 Syncro Westfalia 1.8t Restoration
http://www.thesamba.com/vw/forum/viewtopic.php?t=418933
"Do it the right way, or you'll pay for it" |
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captnbilly Samba Member
Joined: April 21, 2006 Posts: 195 Location: tampa bay
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Posted: Thu Nov 02, 2006 9:43 pm Post subject: |
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As does mine, Casey. I have installed a bypass for the T2 head temp. sensor which basically involves installing an air/fuel gauge and 0-2.5K rheostate to fool the ECU. (A search on this site will pull up my comments). As Probst ("Bosch Fuel Injection & Engine Management" - Bently Pubs.) notes in chapter 7 ("Tuning for Performance and Economy") maximum power is achieved (theoritically) at about 13.2 A/F while maximum economy is around 15.5 AF. So if I'm humping up that long grade and able to hold the 3.2K - 4.0K "torque sweet range" in 4th I'm rolling in that power AF setting. If I'm cruising along at, say 70, and I'm holding in the sweet range (generally around 3.8-3.9K @ 70) I'm dialing in that economy setting (while watching my head temp.- rich settings will cool, lean settings have the potential to over heat), but its not freak out/white knuckle time - left to its own devices, the ECU runs lean alot (generally absolute manifol pressure driven thru the decel valve and pressure reg. valve). With an A/F installed you can observe how the ECU functions on up, down and flat grades, etc. and get a feel for how Bosch designed (and VW no doubt tailored) L-Jet for the T2 flatey. But the MEGASQUIRT (30 yrs. and tons of ECU advancement later) just erases all this hassel. I see folks on this site looking to retro L-Jet or struggling with carbs. Reading all the stuff on mega, why would you move a mountain to build a mole hill? And I will get there, maybe sooner, maybe later, but I have seen the light. Later, Bill |
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nemobuscaptain Samba Member
Joined: March 07, 2002 Posts: 3874
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2tonejoe Samba Member
Joined: August 22, 2006 Posts: 122 Location: Newport News, Virginia
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Posted: Thu Nov 02, 2006 10:41 pm Post subject: |
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my question would be; what do you really gain in the end? Really? Would you go from 18mpg to 40 or are you going to go from 18 to 20? I agree with nemo . . . . . seems like it would be hosey. |
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captnbilly Samba Member
Joined: April 21, 2006 Posts: 195 Location: tampa bay
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Posted: Fri Nov 03, 2006 8:34 am Post subject: |
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Skeptical is good. I certainly didn't suggest, or mean to suggest, that my approach was the be all and end all for everyone. What I thought I said and meant to say was: "These are observations I have accumulated regarding a modern solution L-Jet problems. Here is the experience(s) I have had and here are threads to get you started if your interested in pursuing the subject."
Lots of different approaches/philosophies to late T2 ownership. Low riders, daily drivers, cruisers, campers, junkers, show buses, hard core, passing fancy, whatever - its all over the place. I'm a long range, high speed (relatively) cruiser. If I can't knock off 700-800 mi. a day I'm not trying. But I wouldn't drive to the store in my Westy on a bet. Hi speed cruisin is demanding on a T2 engine (see e.g. Scott's discussion regarding late T2 F.I. running lean, engine overheating, A/F ratios and CHT's at German Supply):
http://www.germansupply.com/xcart/customer/home.php?gspage=customer/main/tech/cht/cht_install.tpl
So what do I gain? Confidence in my system, knowledge that I will catch something going out of spec or normal perimeters before real damage is done (usually 50 mi. from nowhere), fuel efficiency, longevity. If you've spent an hour noodling around the megasquirt forum and deem it "homebrewing" so be it; gentlemen can agree to disagree. Bill |
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casey79westfalia Samba Member
Joined: May 22, 2003 Posts: 1716 Location: Baltimore
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Posted: Fri Nov 03, 2006 9:29 am Post subject: |
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I love when people try to knock something like this. Captnbilly you have explained well. The great thing about the megasquirt is you can control the parameters alot better allowing for better running conditions at all rpms especially higher rpms and under load. Thanks for you great post. I plan on seeing how my ljet performs for now and then possibly swapping to megasquirt next year! Head temps have been great an no valve adjustments at all so everything seems ok for now!! _________________ 66 Westfalia
87 Westfalia Syncro "Phoenix"
88 Double Cab
76 Porsche 914
2014 Audi Q7
2010 Tdi Sportwagen
Currently looking for 62 Double Cab, 66 Westfalia Parts!
(Rear seat and pedestal, bumpers, mirrors)
http://www.baycountrymotors.com
My 87 Syncro Westfalia 1.8t Restoration
http://www.thesamba.com/vw/forum/viewtopic.php?t=418933
"Do it the right way, or you'll pay for it" |
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JMazier Samba Member
Joined: February 20, 2006 Posts: 900 Location: In my garage, Georgetown, Ontario, Canada...
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Posted: Fri Nov 03, 2006 9:35 am Post subject: |
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casey79westfalia wrote: |
Head temps have been great an no valve adjustments at all so everything seems ok for now!! |
Can you give me an idea of what your head temps are like at different speeds/loads? I am curious as I watch mine... _________________ Cheers!
Jérôme
’79 Cali Westy 2.0 F.I.
'74 Honda CB 350 Four
'78 Honda CB 750 K
'12 Golf GTI
'11 Ural Patrol |
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captnbilly Samba Member
Joined: April 21, 2006 Posts: 195 Location: tampa bay
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Posted: Fri Nov 03, 2006 9:43 am Post subject: |
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CJ - also see Scott's remarks at the GermanSupply site I quoted above. Mine runs around 350-375. In late July at hi speed on a 95+ day I saw CHT heading toward 400f. Rolled in the T2 A/F enrichment and knocked off 30F in ten minutes. Seems to work o.k. for "home brew". |
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germansupplyscott Samba Member
Joined: May 22, 2004 Posts: 7090 Location: toronto
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Posted: Fri Nov 03, 2006 9:50 am Post subject: |
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captbilly,
we need pictures and details of your setup. _________________ SL |
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casey79westfalia Samba Member
Joined: May 22, 2003 Posts: 1716 Location: Baltimore
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Posted: Fri Nov 03, 2006 9:59 am Post subject: |
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Yes I agree pics please!
Cjmazier, my temps hover around 300 around town and max at about 325-330 under load. Screaming up a hill I was almost able to get it to 340. _________________ 66 Westfalia
87 Westfalia Syncro "Phoenix"
88 Double Cab
76 Porsche 914
2014 Audi Q7
2010 Tdi Sportwagen
Currently looking for 62 Double Cab, 66 Westfalia Parts!
(Rear seat and pedestal, bumpers, mirrors)
http://www.baycountrymotors.com
My 87 Syncro Westfalia 1.8t Restoration
http://www.thesamba.com/vw/forum/viewtopic.php?t=418933
"Do it the right way, or you'll pay for it" |
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germansupplyscott Samba Member
Joined: May 22, 2004 Posts: 7090 Location: toronto
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Posted: Fri Nov 03, 2006 10:07 am Post subject: |
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casey79westfalia wrote: |
Cjmazier, my temps hover around 300 around town and max at about 325-330 under load. Screaming up a hill I was almost able to get it to 340. |
we must compare apples to apples. what kind of CHT gauge?
it is very difficult to compare one person's CHT readings with another's. the gauges are too inconsistent, from one brand to another and even within the same brand. and that includes the supposedly near-perfect dakota digital gauges. i have had a chance to look closely at the DD gauges and i am not blown away by them. they are as prone to error as any other gauge as far as i can tell. _________________ SL |
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JMazier Samba Member
Joined: February 20, 2006 Posts: 900 Location: In my garage, Georgetown, Ontario, Canada...
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Posted: Fri Nov 03, 2006 10:22 am Post subject: |
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germansupplyscott wrote: |
casey79westfalia wrote: |
Cjmazier, my temps hover around 300 around town and max at about 325-330 under load. Screaming up a hill I was almost able to get it to 340. |
we must compare apples to apples. what kind of CHT gauge?
it is very difficult to compare one person's CHT readings with another's. the gauges are too inconsistent, from one brand to another and even within the same brand. and that includes the supposedly near-perfect dakota digital gauges. i have had a chance to look closely at the DD gauges and i am not blown away by them. they are as prone to error as any other gauge as far as i can tell. |
Thanks for all of the readings! So is there a way to "calibrate" the gauges? Not necessarily change the reading but to at least know how far off they are? If both DD and VDO are inaccurate, what can we compare them to? Any thoughts? What about a Fluke meter (did I spell that right?)? _________________ Cheers!
Jérôme
’79 Cali Westy 2.0 F.I.
'74 Honda CB 350 Four
'78 Honda CB 750 K
'12 Golf GTI
'11 Ural Patrol |
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ratwell Samba Member
Joined: April 26, 2003 Posts: 8717 Location: Victoria, BC
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Posted: Fri Nov 03, 2006 10:28 am Post subject: |
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germansupplyscott wrote: |
i have had a chance to look closely at the DD gauges and i am not blown away by them. they are as prone to error as any other gauge as far as i can tell. |
I'd like you hear your reasons why... _________________ '78 Westfalia CDN
'76 Doublecab
Read the Baywindow FAQ |
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JMazier Samba Member
Joined: February 20, 2006 Posts: 900 Location: In my garage, Georgetown, Ontario, Canada...
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Posted: Fri Nov 03, 2006 11:02 am Post subject: Re: The future of T2 F.I. |
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Captnbilly, the first link has a huge amount of info...it will take some time to digest... The second link is very interesting to say the least! I am currently running a modified (higher compression, larger valves, balanced, mild porting, longer duration cam) 2l in a 79 California with the stock FI and have been considering going to the federal setup however I will also do some reading on Megasquirt now as it seems to be a viable option. I especially like the fact that it is a good method the learn how FI really works. Thanks for sharing... _________________ Cheers!
Jérôme
’79 Cali Westy 2.0 F.I.
'74 Honda CB 350 Four
'78 Honda CB 750 K
'12 Golf GTI
'11 Ural Patrol |
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casey79westfalia Samba Member
Joined: May 22, 2003 Posts: 1716 Location: Baltimore
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Posted: Fri Nov 03, 2006 12:03 pm Post subject: |
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I am using a vdo guage but I also own a dakota digital. My vdo guage is 5-6 years old and is very accurate. The vdo guages in the last 2-3 years are a different story. I have tested both vdo and dakota guages in a pot of boiling water and in the stove .They read very close of one another. I noticed that as temps get higher the dakota digital becomes less accurate while the vdo stays relatively acurate to the stove temp _________________ 66 Westfalia
87 Westfalia Syncro "Phoenix"
88 Double Cab
76 Porsche 914
2014 Audi Q7
2010 Tdi Sportwagen
Currently looking for 62 Double Cab, 66 Westfalia Parts!
(Rear seat and pedestal, bumpers, mirrors)
http://www.baycountrymotors.com
My 87 Syncro Westfalia 1.8t Restoration
http://www.thesamba.com/vw/forum/viewtopic.php?t=418933
"Do it the right way, or you'll pay for it" |
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captnbilly Samba Member
Joined: April 21, 2006 Posts: 195 Location: tampa bay
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Posted: Fri Nov 03, 2006 12:27 pm Post subject: |
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here's what captnbilly thinks he knows about CHT and T2's. Back in '98 I picked up a CB Performance dual CHT guage w/ "J" probes. For reasons lost in time, rather than under the plug, I put the probes on exhaust studs at #1 & #3 cylinders. At a 100k mi., an engine swap, at least 2 additional exhuast copper gasket changes later those probes are history. So I picked up replacement "J"style probes at Aircraft Spruce & Supply. They are under the plugs at #1 & #3 (I like to think its because these cylinders are furtherist from fan, maybe valid, maybe not). I never considered I was ready actual temps. Even a modest noodling of CHT theory/application, e.g.
http://www.efunda.com/DesignStandards/sensors/thermocouples/thmcple_theory.cfm
or
http://www.freepatentsonline.com/4120201.html
is enough to convince me cost/benefit ratio for precision doesn't work for me. Yes, you can get temperture/cold junction compensated systems that are pretty darn close (if you move up to aircraft quality - try Sporty's or Aircraft Spruce) but I agree with Scott, its relative and the point is to understand, overtime, the behavior and relative relations between my two cylinders AND compensations for athmospheric temp. changes that effect the cold junction values on my uncalibrated system. If you wanted to be "ratwell" smart, you could use an infrared temp gun to build a deviation/compensation table. Or you can just watch them as you put on the miles and start to get a sense about whats right and whats not. The wisdom gained from small aircraft engine management (e.g. Continental C-90's, Lycoming O-235's) has alot to offer in building and maintaining a robust and reliable power plant behind you. Just to cite a recent and relevant example:
"Running the engine very hot will put stress on the valves and guides, whose temperatures track CHT's not just EGT's. (According to a NACA study, exhaust valves run hottest at around 40* rich of peak EGT.)" from April'06 Kitplane Magazine. Anyway, that's my approach and reasons why. Now if I could just figure out how to put pictures up. |
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casey79westfalia Samba Member
Joined: May 22, 2003 Posts: 1716 Location: Baltimore
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Posted: Fri Nov 03, 2006 12:35 pm Post subject: |
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Captnbilly Thanks for that post! Please hang out in here more often we can all benifit from your knowledge. I agree the guages are more of a trend indicator. I check my valves more often then normal as I have had so many dropped valve seats in the past that I like to know what my engine is doing. I have not seen my valve clearences move at all since my raby rebuild which was 1000 miles ago. I know that Jake plans on doing a study on cht guages with Gerogia tech I believe and we should be able to narrow down which guages really are the best. I am going to sell my dakota digital as I am not impressed with its performance. It works but not what you would expect for the price tag!
Tp post pictures click the img butoon then paste your link then press the img but again. It will oook like this:
[img]your link[/img]
you images need to be hosted (server) from somewhere! _________________ 66 Westfalia
87 Westfalia Syncro "Phoenix"
88 Double Cab
76 Porsche 914
2014 Audi Q7
2010 Tdi Sportwagen
Currently looking for 62 Double Cab, 66 Westfalia Parts!
(Rear seat and pedestal, bumpers, mirrors)
http://www.baycountrymotors.com
My 87 Syncro Westfalia 1.8t Restoration
http://www.thesamba.com/vw/forum/viewtopic.php?t=418933
"Do it the right way, or you'll pay for it" |
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[email protected] Samba Member
Joined: June 14, 2002 Posts: 1663 Location: Palominas AZ
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Posted: Fri Nov 03, 2006 2:02 pm Post subject: |
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As I posted elsewhere...
I remember back in my "youth" (about 1981 or so) an aritcle written by a friend of my dad's for the Model T Club newsletter. In this article it's explained that the author has a "deep sence of sympathy" for the future youths of this country - as they will not have cars to work on. Or - more appropirately - the computer systems will not be rebuildable when they fail, the components will be obsolete, and all in all, the new stuff just wont last.
I think this megasquirt is the answer to that article. I doubt anyone thought back in 1981 that people would be proposing a "replaceable" ECU for the FI systems that are in place. They also didn't anticipate the "shade tree programmers" that would take up this responsibility and even make the systems of these older cars - customizable.
I think that there will be a great future in the industry of making programable FI systems that are "plug and play" to the old FI systems. Think about it - you'd only need to make a serial to ECU adapter that will read the outputs from the various sensors - and output the propper signal to the the injectors for firing. Easy peasy....
Then make that system universal, and make various adaptors. Pre-program definition files for the various applications - VW, Audi, Porche etc - and you have a kit that replaces all the old stuff.
hrm.... _________________ Ryan
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1963 Beetle
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captnbilly Samba Member
Joined: April 21, 2006 Posts: 195 Location: tampa bay
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Posted: Fri Nov 03, 2006 5:44 pm Post subject: |
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casey - cool i.e. [img]your link[/img]. I know the images are on this computer and they have the as attachments with JPG suffix so I'll get
after it next day or two. They were attached as email, does that mean they were hosted and how do I determine the server?Back in the '80's I picked up some EET automation & robotics degrees. Auto F.I. ECU's are simply a specialized class of what electrical/industrial engineering terms 'controllers'. The '70's era bosch's are analog (discrete transistors, capacitors, resistors, so forth yielding continuous variable output). Todays stuff is digital (megasquirt uses a motorola universal controller chip) and yields discreet steps. Thus when you look at tbones values you see he has a table where he has entered values. This is called a lookup table in controllereze. All your doing when you load up the controller's EPROM (its firm ware) is set values in registers. The CPU at the heart of the controller is like a micro midget reading gauges (rpm, map, air temp, lambda) and setting his knobs (injector pulse length, timing advance/retard) at values that have previously proven to be correct for the existing conditions on the applicable platform. And it all gets adjusted/reset 100 times a sec. So, as solex notes, given a stock "best and proper" condition '78 Cal. T2, once the map is defined, in theory, all '78 Cal. T2's should run just fine on it. My sense is this has come down to the hobby world because 1) there's not enough scale to be profitable, 2) the burgening 'open systems' movement has rendered propriety systems obsolete. A strong VW club with sufficient compatable platforms could take on the developement as a one-off project and then you just duplicate. I'll find those pictures. |
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