1 2 3 4 ... 6
drivendaily New Reader
4/12/16 6:22 p.m.
petegans wrote: Holy E36 M3 this rules! I laughed at the difference in engine size from above photos. Gotta love rotaries.

There are compromises to the rotary, make no mistake. They're really inefficient with the fuel you give them. They can't make the massive torque numbers that larger-displacement engines can. They ... oh, is that it? I guess just two compromises: Displacement and efficiency.

drivendaily New Reader
4/13/16 12:43 a.m.

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 half cleaned s30 dashboard

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. fiberglassed s30 dashboard

Fitzauto HalfDork
4/13/16 9:19 a.m.

In reply to drivendaily:

Im following this part for sure. Need a lighter dash for the race car.

drivendaily New Reader
4/13/16 10:03 p.m.
drivendaily New Reader
4/14/16 4:53 p.m.

Today was the first major setback of the project. As it turns out, my front subframe is twisted. That skews all of the suspension pickup points, and definitely changes the timeframe (and cost) to completion. My budget is already exhausted, so I'm going to have to have my fabricator wrap up the rest of the car and hopefully find a local with a g35/350z that I can take suspension pickup measurements from, and replicate that so it's "good enough" for Ascutney. This is definitely going to be a challenge, there's no way around it.

s30 front suspension

drivendaily New Reader
4/24/16 12:08 p.m.

This is enough of a setback that I won't even have this car back in time for Ascutney 1. I'll either have to throw the CRX or RX7 together (most likely un-caged, which means I can't break out) or rent a car from another racer. I like to think that at this point, I've proven myself to be just competent enough to not throw cars off into the bushes willy-nilly and someone will be willing to loan/rent a car to me. I have my eyes on one momentum car in particular, which should be reasonably similar to the Miata.

This thread may get a little off-topic for awhile here. My options include:

CRX and RX7


Needs some sort of wiring, possibly new injectors. After that, a windshield and new seat mounts and a harness. Not too bad, overall, but I'd have to actually focus on it.


Needs fuel tank plumbing. The stock fuel pump mount is just silly, and I wish I had just opted for a fuel cell rather than sorting this out. Otherwise, it's ready to tune the suspension then race with the wheezy little DPFI engine.

This is the ridiculous pile of awful that Honda said was, "good enough" for the CRX. CRX fuel tank lines


If I want to get ambitious, I could plop the high-compression d16z6 and si transmission that's sitting in the garage into it. I'm told this cranks out around 155whp, which should be pretty good in this car. d16z6

That requires a dpfi->mpfi and obd0->obd1 conversion though, and to be honest, I've had my fill of wiring for this lifetime. Trying to complete wiring jobs when you're colorblind is a new flavor of hell. It's almost as repulsive as mayonnaise.

Other News

There've been other things going on as well!


During the off-season, some of the other hillclimbers and I have been going karting to keep our driving skills from getting too dull. This month was our last race of the season, and I had a pretty spectacular off. I got pushed into the wall ... then onto the wall ... then over the wall and onto the tires beside it. It just proves that practically nothing can ruin a day of karting.



While I wait to get the Datsun back, or decide what to do in the meantime, I've been wrapping up my Honda cl360 for the season. It needed new controls, a re-wire, and new tires all last season, and I'm just getting around to it now. I've also been helping a friend out with her cb350, and my girlfriend just got a cb360 for her birthday ... which, as it turns out, has a seized engine.

Honda Bikes

They're simple enough that anything short of an engine rebuild is only a weekend project. To prove it, here's the "race harness" that I just mocked up, which is enough to run the engine and charging system. I have a separate harness together for the lighting system, but as far as mechanical components are concerned, this is all of the necessities.

Honda cl360 wiring harness

drivendaily New Reader
4/29/16 5:38 p.m.

I'm going to try to get all these parts on this chassis in time for Ascutney.

I'm going to be pressed for time, so I'll probably just post updates on Driven Daily on Facebook for this.

java230 HalfDork
4/29/16 8:36 p.m.

In reply to drivendaily:

"It's almost as repulsive as mayonnaise." Yes, finally yes, someone who agrees with me!

drivendaily New Reader
5/2/16 8:42 p.m.

My weekend was spent giving parts away, receiving parts, and cleaning the garage. It was quite a feat, and I'm just about ready to start work.

Here's what Friday looked like: Friday's disaster

... and now a car could probably squeeze in here, but I'm not quite prepared for that yet. Sunday's workshop

The first bit of work happening to the car is cleaning up Dave's old 6gal fuel cell, which should be perfect for the Honda. I'll lose my fuel level gauge, which makes daily driving it a little more challenging, but it means I don't have to mess around with Honda's ridiculous OEM 'fuel tank solution'. Fuel cell cleanup

You may recognize the radiator in the background from such threads as Dave's RX7 Hillclimb Thread

Here's what Honda said was 'good enough' Honda CRX Fuel Tank

Even after replacing it with a new unit and new straps, dealing with their lines just isn't worth it. Hopefully I can sell all this stuff to another CRX owner. CRX clean fuel tank

drivendaily New Reader
5/17/16 8:54 a.m.

I really started smashing on the CRX this weekend, and plan to publish a video every day until I leave for the race on Friday (I'd like to be able to pack and relax a bit on Thursday). I'm reasonably happy with the videos so far, so I'm going to keep making them until someone tells me to stop.

2016 Hillclimb CRX

The full playlist is on YouTube here: 2016 Hillclimb Prep

drivendaily New Reader
6/17/16 1:26 p.m.

It has returned. Now to sort out where the front suspension is going to live. Datsun s30 is back home

ssswitch HalfDork
6/17/16 4:34 p.m.

I loved the videos. Jealous of how quickly you get things done. Sorry it didn't turn out, but no plan survives contact with the enemy.

Nice to see that you also paint while in a hurry, I've always felt ashamed about "wasting time" cleaning up rust and sealing the bare metal.

Welcome back, Datsun.

simon_C New Reader
6/17/16 8:40 p.m.

Loving this project. I used to live in Manch too, Good to see there's still some car people there working on cool projects. I haven't had my eye on the scene there in about 4 years.

drivendaily New Reader
6/18/16 3:20 p.m.
ssswitch wrote: I loved the videos. Jealous of how quickly you get things done. Sorry it didn't turn out, but no plan survives contact with the enemy. Nice to see that you also paint while in a hurry, I've always felt ashamed about "wasting time" cleaning up rust and sealing the bare metal. Welcome back, Datsun.

Filming and editing took longer than the actual work, so that was an issue. The real key is to establish small bite-sized chunks of work early on, and the simplest definition of your 'end of project' goal as possible. In this case, it was, "Make the CRX safe again."

Paint has its uses. I really don't care about doing a good job, I just hate having crap fall in my face while I'm trying to do things. It's distracting.

simon_C wrote: Loving this project. I used to live in Manch too, Good to see there's still some car people there working on cool projects. I haven't had my eye on the scene there in about 4 years.

There are a few people building greatness in Manchester, but I only know a couple people who actually race. Coincidentally, they race CRX's.

drivendaily New Reader
6/28/16 5:59 p.m.

After a lot of trying to figure out how to make it work, I've determined that I can't use any of this chassis work after all. The main hoop is too far forward, and I can't place the seat anywhere that makes sense. I'm pretty short (5'6") but I really won't be able to get in or out of the car at this point. 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.

drivendaily New Reader
8/8/16 7:57 p.m.

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".

Driven Daily Datsun roll cage design

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). Nigel's ETS UTE

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. Datsun wrap-up

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

Sticky tires

drivendaily New Reader
8/13/16 2:21 p.m.

The s30 is all ready to be repaired and re-worked, but I still have to wait on materials and tooling before I can really dig in.

Datsun goes into ICU

dextervw New Reader
8/15/16 7:33 a.m.

why does the cage hang so low under the door opening?

DaveEstey PowerDork
8/15/16 8:41 a.m.

In reply to dextervw:

Illusion because the car has no rockers right now

ebonyandivory UltraDork
8/15/16 9:07 a.m.

Don't underestimate how well this is written i.e.: very easy to read and follow.

Very clear and concise. That just adds to the awesomeness of this thread.

drivendaily New Reader
8/15/16 1:12 p.m.
DaveEstey wrote: In reply to dextervw: Illusion because the car has no rockers right now

Exactly that. I'll have my floor at roughly the same height, but the plan is to use round tube.

ebonyandivory wrote: Don't underestimate how well this is written i.e.: very easy to read and follow. Very clear and concise. That just adds to the awesomeness of this thread.

I appreciate the compliment. GRM chose to use a forum that uses Markdown, and that makes it a lot easier for me to format. I started filming for a video series this weekend, so my updated will likely slow down while I record and edit those.

drivendaily New Reader
8/18/16 8:47 a.m.

I had an early morning today, and headed down to the Makerspace at 6am to accept delivery of almost $1k in steel.


I ended up going through a local supplier called Choice Metals, and can't speak highly enough of them. They had my 1.75" outer diameter .095" wall and 1.5" outer diameter .065" wall A513 1020 drawn over mandrel tubing. The only thing available in the US that's better is 1026 instead of 1020.

Cage Tubing

I had originally planned on 1.25" for non-safety-critical components, but after a chat with Walter (one of our tech inspectors, who is an absolute wealth of useful information), I increased it to 1.5". The weight cost and strength gain is inconsequential, but Walter offered insight that hadn't even occurred to me: 1.5" tubing provides increased surface area against the 1.75". That means that the weld joints will be stronger than 1.25" - and that matters quite a lot.

Datsun cage components

Getting Jiggy

The floor of the Makerspace is far from level, so I need to fabricate a chassis table. That's what all the 2x4 rectangular tube is for, and it's just going to be a known-square reference point that I can bolt/weld jigs to. I have ideas about what to build, but haven't drawn up plans yet. I'd love to see some reference drawings from other people.

Prepping to Bend

None of this gets exciting until I start bending and welding, but there's a lot of work to do leading up to that. The general plan is to:

  • Build the frame table
  • Jig the body (similar to this s13
  • Jig the front suspension pickup points
  • Measure and 'rough cut' lengths of tube
  • Mark my coping measurements on those lengths

I'm not even going to order the bender 'till September, since there's so much to do before I can even start using it. This is the start of a very long road, and the goal is (once again) Ascutney 1.

drivendaily New Reader
8/18/16 6:57 p.m.

I got around halfway through my the jig cuts after work today. With a little luck and a bunch of determination, I hope to finish welding it this weekend. Datsun chassis jig

drivendaily New Reader
8/21/16 9:08 p.m.

Instead of using the big beefy 3phase MIG welders at the Makerspace, I brought my teeny little TIG down and trimmed, cleaned, and tacked everything together.   Chassis table   This might show why "jack stands on bits of wood" won't work for this build. The jack stands would just fall over; The floor is THAT bad. My chassis table is within 0.05[font=arial, sans-serif]° [/size][/font]on all three planes.

Compared to the floor   I'm pretty pleased with the results, overall. The plan is to finish welding it by the weekend, then jig up the front suspension.   Steering is going to be a bit of an issue. Rotary engines have a little bit of trouble with rear-steer (when the steering rack is behind the front axle line, rather than in front of it) because they dip down so low. I might have enough space to have the entire engine behind the steering column, otherwise I may have to place it higher in the car than I'd like. I'll deal with that after next weekend though. Right now, I'm relaxing after an oppressively hot, sweaty, humid weekendrolling around on an un-level concrete floor.

drivendaily New Reader
8/31/16 8:31 p.m.

This project is definitely slow-moving, but I managed to finish the chassis table up within 0.01° (the most precise measurement I can takeand am extremely happy so far. I have a few weeks before my tubing bender arrives, so I'll probably add some 1" square tube reinforcement to keep it rigid no matter what.

Chassis table

1 2 3 4 ... 6
Our Preferred Partners