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    Thread: Building the Ultimate 1983 Rabbit GTI (vw mk1)?

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    1. 01-19-2013 02:57 AM #1
      [Editor's note: I realize that using the word 'ultimate' in this forum heading is over stating things. The only possible 'ultimate' 83 GTI would be to go into a time machine and go back to 1983 and buy a totally stock example and drive it around. But that isn't possible and you simply can't get NOS shocks and springs. That said, you could get damn close to the original stock feel with a great deal of care and attention to detail. And that would be the modern equivalent of the Ultimate GTI. In defense of my use of the word 'ultimate', I was an original GTI owner, and I was wrenching on it from the day I bought it, and racing it, like countless other GTI owners have done over the years. These cars were meant to be modded and raced and that is the position I have come from: to keep the spirit of the original car, in a modified, but totally streetable sense, without a huge turbo system or other 'over the top' change in behaviour ....]

      I want to let the readers of vwvortex.com know that I am deep into a new project of significant personal meaning to me as an original owner of a 1983 GTI that I spent countless hours building up over the period of 1983-87. I have acquired another US spec GTI of the same build date (Nov 82) and have engaged Techtonics Tuning and a host of other vendors in the task of building the ultimate streetable GTI while keeping true to the original car.

      You can follow this project at: http://derekspratt.com/HTML/Automoti...als_Specs.html

      You can also comment on this project either on this vwvortex thread or on the blog on my web site - I want your feedback and input as this project progresses.

      We are trying to build a car with excellent street driv-ability and manners, a car that looks stock inside and out, but takes on a new dimension when you look under the hood or under the car. Think normally aspirated mk3 ABA block with a 95.5mm ABF stroker crank, custom length rods, and 83.5mm 12:1cr pistons married to a 16V 9A head that has everything done to it (oversized valves with 5.5mm stems, 288 solid lifter race cams, lots of porting, etc) - but with a focus on balancing mid-range torque and peak hp. And an AT Power ITB DTH intake system - all adding up to a targeted 240hp at or slightly above 8000rpm, plus a custom radiator, a trick 020 AGB 2Y (mk2 16V) close ratio trans with a Quaife diff, and many many more goodies including a dry flow nitrous system, all controlled by a Holley HP EFI ECU. And the suspension system, brake system, and everything else is new, top drawer, and streetable as well.

      So tell me what you think. I am in the middle of cutting out the rust from the project car, and starting to weld in new sheet metal, while I carefully design a whole series of stiffening elements to make this car structurally tight and safe at speed. The engine is coming together quickly, the trans is finished, the suspension is 'in hand' and the braking system is not far behind. But there is a ton of chassis development, bodywork, paint, interior work and final assembly ahead of me.

      Here's to all of the vw mk1 fans out there that want to build cars that embrace some new technologies while keeping true to the original car in most ways ...

      Cheers,

      Derek
      Last edited by Derek Spratt; 11-21-2015 at 03:27 AM.

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      01-19-2013 08:11 PM #2
      Opinions are like a$$holes, everybody has one, here's mine:

      IMO what you're describing is clearly superior, has been done in variations many times, and would not be "true" to the original GTI.

      Just the addition of more valves betrays the simplicity of the original concept. Build up a Techtonics 8 valver, those sorts of mods, and enjoy an "improved" GTI that is still a GTI: a little lacking in everything and more fun than the sum of its parts suggest it should be, which was the point.

      But OTOH, do as you wish and enjoy

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      01-19-2013 09:05 PM #3
      Sounds like a delightful midlife crises ill watch Vr eaters are always entertaining

    4. Member justin_6649's Avatar
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      01-20-2013 12:48 PM #4
      sorry man but this is definitely gonna ruin the inside of the car

      http://derekspratt.com/Images/Automo..._VZ401_540.jpg

    5. 01-20-2013 04:43 PM #5
      I thought long and hard about building another 8v motor but I was always dreaming about a 16v head, even back in 1983. The 8v heads just don't flow that well, not being cross-flow, etc. The benefit of an 8v head isn't just to be period correct, which would have been nice, but it would have kept the mid range torque feel of the mk1 GTI more accurately represented. We are going to work hard to make the 16v engine torquey though.

      In regards to the audio control unit, the idea is to have access to bluetooth for celphone use, which is the law in BC where I live and also to allow me to connect my smartphone as the source of music - which is my life these days. By having all of this functionality hidden in a pop-up LCD unit that collapses to a std 1 DIN faceplate, that is ideal for me. I can leave it hidden 90% of the time, and only need to pop up the LCD when programming is required.

    6. Member justin_6649's Avatar
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      01-23-2013 10:27 PM #6
      Quote Originally Posted by Derek Spratt View Post
      In regards to the audio control unit, the idea is to have access to bluetooth for celphone use, which is the law in BC where I live and also to allow me to connect my smartphone as the source of music - which is my life these days. By having all of this functionality hidden in a pop-up LCD unit that collapses to a std 1 DIN faceplate, that is ideal for me. I can leave it hidden 90% of the time, and only need to pop up the LCD when programming is required.
      to each their own i guess, i just bought an original radio because i found a nice new uncut dash bezel. i dont even have speakers in the car! cant wait to put it in, good luck with your build

    7. 01-22-2013 10:57 PM #7
      I'm really digging your plans for this one. Take everything that the mk1 gti was (the best real driver's car ever designed, IMO) and build everything to the highest level. 16v motor tuned for low-end power, same gear ratios (with a slightly higher ratio r&p to accomodate the increased power), less unsprung weight, stock unassisted steering, stiffer springs, dampers and chassis, and it will be a blast to drive! Same basic design and balance, just better everything.

      The 16v motor should be fine and I can't honestly think of a better choice (aside from maybe a super-built, all-motor 8v, which would end up being more expensive to get the same power - and probably end up having a very similar powerband to your 16v), I think the 16v gets a bad rap from its use in the heavier mk2 models, where the rush of extra power at the top end made it feel less torquey in that car. In any event, its going to be head and shoulders above a turbo'ed 8v torque-wise.

      I think your biggest challenge will be getting the suspension dialed in where you want it, but I think you're on the right track with starting out with no front swaybar. Might want to plan on moving the battery and as much other weight to the rear from the start, every little bit helps.

      Good luck, I'll be watching this one for sure!

    8. 01-23-2013 03:00 AM #8
      bpetry, thx for the kind words of support. I think you nailed it but even though my goals are lofty I am nervous about all of the design/spec decisions (similar to building a new home), and not knowing whether it will all come together to create that pure driving experience that I crave.

      I know I can create a stiffer chassis that is lighter than the stock GTI, and in some areas it will be a necessity, not a luxury, as having sturdy engine and transmission mounting points with this engine will be a must for reliability/safety alone.

      The folks at German Transaxle helps me spec the 020 2Y close ratio Scirocco 16V transmission. We decided to not mess with the stock ratios or final drive so it really should be as you describe.

      Josh at TT has been amazing to speak with. He is really hand holding me on many aspects of the vehicle design/implementation as he has put together so many mk1s over the years covering everything from street, strip, road racing and off road racing applications. And he's had his own cars. So he steered me in the direction of the engine block, crank, rods, heads, valve-train components, cams, everything in the quest for street manners, and broad torque more than HP. He's pumped about the potential with the engine as he is using every last tip and trick he's used and he gets to plumb the intake with the awesome AT Power DTH TBs. He isn't convinced that the H&R race springs are the best move but I'll just have to drive it and start to tune it from there. The struts can be custom valved by Bilstein and I can always move down one level to the H&D sport springs or add a front sway bar. My last GTI had a pretty firm ride and had huge sway bars so I'm betting I'll like the ride ...

      The choice of a bigger 16V engine is really due to the fact that I always wanted more from my 8V than we could get with head/drivetrain upgrades alone. I love free revving engines and I just know that 200+hp streetable hp in a stiffened mk1 chassis will be true to the original GTI's character, only better. But this is a very personal thing and I totally respect other people who say that I have given up a bit too much of the originality of the 1983 GTI ...

    9. 01-23-2013 03:01 AM #9
      I posted a web site project update tonight covering the start of the chassis preparation and fabrication ...

    10. Junior Member digdugdagyo's Avatar
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      03-05-2013 12:51 PM #10
      There's an add in the classifieds for a clean red gti dash, as well as other nice interior pieces. I'd link it but I'm on my phone in class.
      Bones heal, chicks dig scars, and The United States of America has the best doctor to daredevil ratio in the world. ~Captain Lance Murdock

    11. 03-07-2013 12:40 AM #11
      I am finished with the underbody seam sealer removal and I am now 1/3rd finished the same with the interior. I have had to use cold spray to freeze some of the glue from the carpets to chip it off. And dry cleaning fluid to remove some of the goo as well.

      I am starting to plan some metal bracing and one of the areas that looks primed for stiffening are the seat mounts but I am suspicious that VW cut all the way thru both sides to allow for some flex on purpose. The only thing I can think of is that there was some resonance that transmitted to the seats and they solved the problem by cutting the seat supports to allow for some flex. I want to weld up those gaps - anyone have an idea here?

    12. 03-15-2013 02:49 AM #12
      With the underside of the car fully stripped of seam sealer I put another week into doing the same for the interior. It is now ready for welding/primer. My last pre-welding task is to finish stripping the engine compartment wires (sorting out what will go/what will stay) as well as prepping that area as well (I have been chipping away at the engine compartment cutting out lots of ugly brackets and clips that will not be used, and planning the smoothing detailing as well).

      There is a new video update and photos posted on the web site ...

      Oh, and really good news on 2 fronts: AT Power shipped my DTH IBs today and TT custom built me a set of stainless steel 1.75" primary race headers for their 2.25" stainless steel exhaust system! How awesome are those guys. Josh, you really are the man.

      And it looks like we will go the route of a custom set of rods as we want to get the max streetable compression out of the motor while still fully unshrouding the valves and matching the shape of the combustion chamber to the cylinder walls (83.5mm). At least we will get the CR bang on 11.5:1 and stick with light-weight forged rods ... we think we can get away with this level of compression because I can still get 94 octane gas in Vancouver, Canada (yes, I will likely have to use some quality octane boost while driving in the US). FYI - With the 288 sport cams we bleed off a bit of compression at lower rpms.

    13. 04-06-2013 02:37 AM #13
      With a 10 day spring break family trip interruption out of the way now I have managed to finish cleaning up the engine bay area, cutting off all of the remaining rusted or otherwise useless metal tabs and brackets that will no longer be required, and have started the process of 'smoothing' the bay area. With all of the seam sealer purged from the car end-to-end (finally!) the project is now shifting to metalwork.

      The biggest issue facing me over all is cutting off the upper inner front fenders where they were rusted out and replacing them. I have elected to cut as little vertical material as possible and will approach this process by re-mounting the doors, hood and grill and then cutting the new inner fender metalwork to size, bolting it to the new fenders, fitting/mounting the fenders when all of the gaps and dimensions are correct, and then spot welding in the inner fenders, then removing everything again, and completing the welding of the inner fenders. This involves the most welding and the most critical welding/positioning/accuracy of all of the welding tasks in front of me but I feel compelled to tackle it now as I am tired of staring day after day at the ****ty rusted fenders. Cutting the rusted metal off last week was very satisfying indeed. I'll get a youtube video posted on this process later this weekend.

      I also received the AT Power curved ITBs and the SMS custom made 'midnight blue' seat fabric. Both are beautiful to hold and stare at hour after hour. See my web site for the photos ...

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      04-06-2013 10:15 AM #14
      Tell us more about how you got the new seat cloth!

      That's been a real stumbling block for many of us. We'd have to basically rely on SMS to randomly "find some", or we pay through the nose (understandably) to get it from hoarders.

    15. 05-20-2013 02:47 PM #15
      One of the things that I wanted to do differently with my GTI project was be far more 'hands on' in terms of executing on the project.

      My Chevelle was a high dollar effort with many people and firms contributing to everything from the engine design and build-up, to the chassis, wiring, paint, etc. I did the Chevelle project when I had small children at home, a very demanding job as CEO of a public company, and I was always feeling rushed and disconnected from the project. I had high goals and in fact created a 40 page plan for the car that targeted 700hp from 502cid, normally aspirated, in full street trim - kinda like my GTI specs now. A high performance street car that was true to its roots. But I made the mistake of putting in a 300hp nitrous system and as soon as we got to the track in 1999 and ran a low 10s pass at almost 130mph just 'on the motor' alone, I wanted to get into the 9s and with the nitrous we ran mid 9s at 140mph - and then I wanted to get into the 8s, and so on. So the car kept on getting faster and more extreme, and less road-worthy, but we did end up winning as Canada's fastest street car on 10" DOT tires in late 1999 with a 9.1s pass at almost 160mph.

      I was getting bummed out about the direction of the Chevelle project as it was no longer suitable as a street car so I started with Danny at Pro Gas on a full-on race car project (our S-10 pro-stock truck which was capable of 6s/200mph passes at the track) and I started the process of reversing the Chevelle race capabilities and building what I wanted: around 750hp on the motor and 1000hp on nitrous, but with digital fuel injection. The long story is that I ran into business challenges in late 2001 with the meltdown of the tech markets (the dot-com bubble) and I was also really unhappy about the S-10 project, which was something I didn't participate in most weekends at the track as I was too distracted on other things, and I realized that I didn't really want a pure race car that I wasn't even licensed to drive (I needed a special license to run faster than 7.5s and it is dangerous stuff too).

      So I went AWOL and sold off everything: S-10, tools, motor-home, trailer, and even the Chevelle. I just woke up one day and said 'I'm done'. And more than a decade later I think I made the right decision - except for selling the Chevelle, which I do partially regret, although I think I am in a better place mentally with my GTI project now.

      My GTI project is all me: in my garage, not 45 minutes from home, with myself doing almost everything from metal to paint, and having my dad and my youngest son helping me. It is bliss. I am getting back to my roots, paying respect to my past, working on a car that was and will again be pure magic to my soul, and a car that ties into my marriage, which my Chevelle and S-10 certainly did not do.

      I am approaching the GTI with a clear eye to keeping the look of the car OEM (except under the hood and under the car). I am keeping the street manners in mind, and I am mindful that stuffing in a huge power plant isn't where I want to go. I always wanted more power in my original GTI and I know that the 2L 16V motor will have more revs and more top-end power but the torque won't be extreme and in the end it should 'feel right' for the A1 chassis.

      There is a bit of the Chevelle in this project, but in a way that is more mature. This GTI will have similar fit and finish - only better. I can see the light at the end of the tunnel now with the welding coming to an end in the next month. Bodywork and paint this summer and then assembly this fall. Yippie!
      Last edited by Derek Spratt; 05-20-2013 at 02:51 PM.

    16. 06-04-2013 01:27 PM #16
      Well, after a lot of cursing and re-calculation I have finally managed to get the unibody sheet metal areas under the doors to be straight/in alignment, and have welded in the first driver side rectangular tube front-rear frame rail, floor pan and additional bracing members. I will get the passenger side work done over the next several days and then will post photos and a video covering this major step forward in the completion of the over-all welding/chassis development ... (there were lots of challenges and lessons learned but the bottom line is that it has all turned out beautifully so I am tired but happy!). Stay tuned ...

    17. 06-10-2013 02:55 AM #17
      After yet more cutting, welding, bending, banging, crashing, cursing and swearing, today I managed to finish getting both front-to-rear 1.5"x1" rectangular tube frame connectors installed correctly (after pre-aligning the body prior), as well as installing both floor pans and additional OEM floor pan bracing, plus some nifty new 'lift points' that will allow me (or anyone else that is servicing the car) to safely lift the car without damaging the unibody sheet metal ... I have posted a few photos and a new video on my web site covering this work.

    18. 06-19-2013 11:36 PM #18
      Check out my new carbon fiber bodywork photos:
      http://derekspratt.com/HTML/Automoti..._Bodywork.html

      I just got back from the UK and brought back the beautiful and extremely light weight carbon fibre body panels and bumpers made by LWS Design for this project. I am super impressed with their customer service as they hand delivered everything to me at the airport before 7am this morning at no charge! The full set of scratch resistance polycarbonate windows will ship separately later this summer. I have also posted a video.

    19. Member foxygrandpa's Avatar
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      06-20-2013 12:17 AM #19
      Wow this is going to be one amazing car when you are done. I dig your taste in cars (looked on your web site) I wish I could afford a supra like your old one but I'm a broke 25 year old haha. It's just refreshing to know that out of all of the power machines you've owned that you want to build a little old gti haha. Thanks for sharing thus far.

    20. 06-25-2013 01:35 AM #20
      Any time you try and MIG weld thin sheet metal you risk 'blow-thru' and this is especially true with older vehicle sheet metal where there has been some rust. I wanted to try my hand at MIG 'brazing' using the same modern European techniques that are required when working with thin boron doped high strength steel panels and/or zinc plated panels - in either case MIG welding puts too much heat into the base metal and both weakens it and vaporizes the protective Zinc coating. So I managed to source some 0.035" diameter MIG brazing wire and adjusted the settings on my welder to lower the wire feed speed but keep the voltage/temperature setting the same as for my 0.023" dia mild steel wire. It worked! The bronze flowed into the gaps and in between the overlapped metal on the lower rear quarter panel patch and I did not once blow-thru the base metal. Highly recommended for sheet metal restoration work ... - June 24, 2013

      One awesome feature of MIG brazing is the ability to sand off the excess bronze without impacting the base steel panels ... (you need to punch some small holes or slots in the top sheet that overlays the lower sheet to allow for deeper flow of the brazing material. Yes, you can butt weld sheet metal but you need to provide enough of a gap to allow the filler material to flow thru and create a bead on the reverse side - think of the bronze filler material as a type of steel 'glue').

      I also found enough time this weekend to weld in additional heavy gauge sheet metal around the rear axle beam mounting points to stiffen/strengthen this area of the chassis ...

      Updated photos and videos on my web site at:

      http://www.derekspratt.com/HTML/Auto...2_Chassis.html

      http://www.derekspratt.com/HTML/Auto..._2_Videos.html

    21. 07-11-2013 01:58 AM #21
      After doing quite a bit of MIG brazing I am more impressed with its capabilities and versatility than ever. I put a lot more time over the past 2 weeks brazing plus I completed the remaining major chassis stiffening/fabrication work via the installation of the remaining interior chassis stiffening components.

      Updated photos and videos on my web site at:

      http://www.derekspratt.com/HTML/Auto...2_Chassis.html

      http://www.derekspratt.com/HTML/Auto..._2_Videos.html

    22. Member
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      07-11-2013 06:54 AM #22
      does the brazing process that you are using require shielding gas? I am wondering if I could run brazing wire thru my junky little flux core welder.

    23. 07-11-2013 08:57 AM #23
      The recommended gas is 100% argon but I used 75/25 mix which seems to work OK. I would assume that without any gas at all you might need to clean up the brazing more but my guess is that you would be ok. The next time I load up the brazing wire I'll try it w/o gas and will let you know ...

    24. 08-11-2013 01:34 AM #24
      Chassis welding is complete and now I have managed to get the under carriage primed with epoxy primer ...

      Updated photo on my web site at:
      http://derekspratt.com/HTML/Automoti..._Bodywork.html

      Updated video on my web site at:
      http://derekspratt.com/HTML/Automoti..._2_Videos.html

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      08-11-2013 05:29 PM #25
      The underside came out really well!

      Consider creating drainage holes in the floor beams, as trapped condensation could be a problem.

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