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Driven Daily Hillclimb 2016 Build

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Most of tonight was spent simply cleaning/organizing. I still don't have a clean floor, but I did get to dig the dashboard out of the basement and start prepping it for molding.


For those who don't know, s30 dashboards were made of vinyl-wrapped foam that was susceptible to cracking if exposed to sunlight for more than a few years. It's pretty close to impossible to find an original, un-cracked dash these days, and most people just toss a plastic cap on top and call it good. Generally speaking, that works great. It looks good, and the dashboard doesn't need to be structurally sound.


However, the stock dash is pretty heavy. I really can't justify trying to use those old original gauges either, especially with a standalone ECU where I can drive any gauges I want. I do love the design of the s30 dash though, so I decided to repair the surface and pull a mold from it. Fiberglass should work just fine for this.


The first step is to fill the large voids left by the cracks. I used some 2lb expanding urethane foam, because it's so easy to work, is fairly rigid, and is stronger than body filler when filling large gaps. I think it took around 15 minutes to go from a badly cracked dash to a mostly-smooth one.



A quick rasping, and I had this



After that, I mixed up some fiberglass reinforced body filler and because it's chilly out, decided to call it a night. I'll get to sanding it down and finishing the surface after work tomorrow.


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I just found out that the g35 front suspension has a twisted crossmember. That means my suspension pickup points are skewed, and I need to get measurements off another car. It's a big favor to ask, but I need someone in New England who's willing to come up to the shop so I can pull the arms off your suspension and measure the pickup points, then put it all back together.


If you want to replace your front control arm bushings, this could be just the right time to go for it. Shoot me a PM here, email me at jesse@driven-daily.com, or call/text me at 413-931-1486.

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  • 2 weeks later...

This is an awesome project. Can't wait to see more progress on this build over the next few months.

This next bit is going to hurt then, I'm afraid.
I'm pretty disappointed to admit that there's no way I'll be able to race the Datsun-shaped-car for the beginning of this season. I won't even have it back from the chassis fabricator's until after the first event. The only reason for going for quick, expensive solutions to problems (BBS wheels, shiny new engine, etc) was to get the car on the hill for Ascutney 1, and now that all feels like a waste. What's more: The car won't be at the events my few sponsors were expecting, so now I need to refund them for their support.
I'm absolutely gutted.
However, I can't just lie down and feel sorry for myself. I still have hillclimbs to race. I had to make a decision as to what to drive, and just accepted a deposit on the rx7 (this is the third deposit I've taken on it ... I'm almost making a profit just on deposits now).
That leaves me with two options: Rent a car from someone else, or do a quick prep on my CRX. If I had more time to put into it, I'd toss a rwd subframe in it and one of the spare turboII powertrains ... but I have less than a month until Ascutney 1.
My best-case scenario is to:
1. Swap out the 325k-mile d15b2 (which was a sad design from day 1) for the high-compression d16z6 engine (sohc 1.6) sitting on a shelf.
2. Toss the 225-series RA1's left over from the Miata on it
3. Tune the suspension as best I can in a short time-period
4. TRY to have a cage installed in it (I have one option for this, and he's pretty busy)
Budget is going to be an issue. Time is an issue that's even more difficult to solve, so I'll probably have to rent a car for the first event, then drive the CRX for a few events. If everything goes great (which is unlikely, when we're talking about race car prep) I might get to drive the Datsun for the second half of the season.
It's going to be a struggle, but I have great friends that I can call in for reinforcements when necessary.
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  • 2 weeks later...

Well, here are some photos of the CRX, then. I can't really do anything with the Datsun until I get it back, and haven't even seen it in months. I started by making a small antenna hole plug, so water doesn't get in.




Cut&fit for the fuel cell



Pulled the old exhaust, laid out the new exhaust



And found a couple cracks in the steering rack subframe. These won't be difficult to repair when I have it out.



The engine is ready to come out, I'm just waiting for a second set of hands to do it.



Edited by Jesse OBrien
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  • 5 weeks later...
  • 2 weeks later...

It's not the headroom that's the problem. It's the X in the main hoop. Even if you put a bent shoulder bar in like I did, the bottom part of that X will preclude the base of the seat from sliding back far enough.

You definitely nailed it. It looks like I'm buying a tubing bender, and starting this chassis prep over. It's really disappointing to miss the 2016 race season, but that's how it goes sometimes. I don't expect to do anything but let it rust in the driveway for the next month, then I'll bring it down to the Makerspace.

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Moving the main hoop renders everything else that was done worthless, as I can't make tube longer to fit. It all needs to be re-done.


This puts me in a tough spot. I'm getting the car back far later than expected (it was at the shop for 7 months now), and it's in a worse state than it left. On top of that, all the money from selling my trusty old Miata went into getting this ready for the 2016 season. Realistically, I don't have any hope of getting this ready to drive this season, and I may miss Climb to the Clouds 2017 because of it.


Still, it's better to light a candle than complain about the dark. I have a year-long membership at the Manchester Makerspace and I may be able to rent a 'large project plot' there for 3-4 months. I'll definitely have to pay for it, but that beats the hell out of trying to make my tiny shop work.


I'll need to buy a tubing bender (likely the JD2 model 3) and some dies (likely a 1.75" and 1.25"), and a respectable amount of DOM tubing.*


All told, being able to do the chassis work myself is going to cost around $3,000 plus my time. I won't have that set aside 'till August (at best) so it looks like it's just going to sit in the driveway for a bit, while I jig the subframes and finish the CRX.

Edited by Jesse OBrien
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  • 1 month later...

I've been sketching out plans a bit lately, trying to strike a balance between strength/safety and weight. Right now, I'm planning to make the primary safety features are going to be 1.75" x .095" DOM, and rigidity reinforcements will be 1.25" x .060".




I'm drawing a lot of inspiration from Nigel's ETS Ute. I've been through that build a lot, and can only come up with minor complaints (square tube floor, I don't love the trans tunnel design, and I don't like the door bars).



Overall, this design estimates out to around 160ft of tubing, and 32 bends. With the combination of tubing, it'll be around 200lb for the chassis structure, including the suspension pickups.

I'm waiting for approval to rent a project plot for 12 weeks at Manchester Makerspace. That gets me a dedicated workarea, and hopefully extra sets of hands to help out from time to time. It's an added expense, but I'd say it's well worth it. My home shop is small enough that I can either fabricate things, or assemble them. This project demands that I do both.

Really, this is what I'm working with right now. I just need to connect it all so that a Datsun body mostly fits on top of it, and a tiny rotary engine fits in front of the firewall.



Also, I've been considering a change in tire selection. Maybe overkill ... but maybe "just enough kill".




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Wish I was still local, I'd be more than happy to come lend a hand. As it sits, sorry to see your plans go so pear shaped, but I'm excited to see what you manage to make out of this! Love the ETS Ute as well, seems like a great inspirational place to start (again) from. 


As for your tire pick, depends on what that side wall says. If it begins with an A and is sticky at room temp, you're golden. Otherwise, you might have a hard time getting them hot without heaters! 

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I just wish I could find a used bender (or dies, even). This stuff is expensive for a "single use" project. I have a few fabricators with great reputations that I could drop this off with, but I'm just not mentally ready for a potential letdown. I can't quite give up control. Instead, I'm committing ~120 hours to chassis/body/jigging work.


As to tires, I have 275/30R17 S.drive tires on my 17x10 wheels right now. The plan is to use those for the first round of shakedowns, as they'll let me feel out the limits of the car at lower speeds and loads, and I can ease into a faster setup. Those wheels are a very tight fit in the front, though.




The slicks are 15" Hoosier bias plys. These are old and hard, but I can get 15" x 15" r25 or r35 (roughly the same exterior compound as a6/a7's) inexpensively. I've never driven on bias ply tires, so I'm still skeptical as to how I'll adapt to squirm, and what additional suspension/alignment considerations I'd have to make. The real upside to running bias-ply slicks is that they're around 5lb/tire, as compared to ~25lb/tire for the s.drives.

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I've got the 15x13 R35 radial Formula Atlantic tires on mine on 15x14 wheels, using the same front and rear. I've only run them once, but I was having trouble getting heat in the rears. Found out my tire pressures were WAY off, so dropping pressure to 18-20 from 30 might help that issue a bit. Was surprised to be able to smoke those huge tires so easily though. I could smoke them for as long as I cared to, just by flooring it. 350ish whp L33 in mine.

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I've got the 15x13 R35 radial Formula Atlantic tires on mine on 15x14 wheels, using the same front and rear. I've only run them once, but I was having trouble getting heat in the rears. Found out my tire pressures were WAY off, so dropping pressure to 18-20 from 30 might help that issue a bit. Was surprised to be able to smoke those huge tires so easily though. I could smoke them for as long as I cared to, just by flooring it. 350ish whp L33 in mine.

Man, that's a lot of power out of an l-series. Wow. I think I'll be closer to 225-250 whp with my rotary build (and around 200ft/lbs or so).


From what I've heard, bias ply slicks are a completely different experience compared to radials. I've only raced on slicks once, and it was a disconcerting experience overall. I'm not used to having so little cold grip, and got a bit out of hand a couple times. I suppose that's the benefit of renting a car from a friend: You get an opportunity to feel out different setups before committing to buying anything. I have to admit that I like BMW's "fast tractor" e30 platform.




My concern with those slicks is finding wheels that don't weigh too much, and actually fit my brakes (g35 brakes are physically large). I'd rather not run crazy offsets that would ruin my scrub radius. Hillclimb racing is similar to tarmac rally combined with autocross, the tire needs are distinctly different from road racing or track days. What kind of racing were you trying the R35's on?

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Heh. L33 is an aluminum 5.3L V8.


When my car was running with an L28, I used the Formula Atlantic front slicks. They were radial Yokohama A005s back then, 250mm wide. They were great, but a little on the hard side. One set would last a full season of autox and a couple of track days, and they would heat cycle out. Never even came close to cording one. They broke loose really progressively, easy to save, etc.


From what I've read, the bias ply slicks like more slip angle and the radials are supposed to be more of a knife edge but faster overall, but my experience with the Yokohamas was that they were very forgiving.

The one time out on the Hoosiers was OK. They wouldn't grip, but I never felt like I was out of control or like the car was difficult to control.


I'm using Bassett wheels. They're 25 lbs each. Not too bad really. I had some stupid heavy steelies with the Yokohamas which were 23 lbs for a 15x8, and the Yokohamas were probably nearly as heavy as the Hoosiers, so for a couple lbs per wheel I've added a lot more rubber...

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