Daily Hillclimb Build (s30)

[drummingpariah]

Sorry for the downtime, I got a little distracted with our rules/awards banquet coming up this weekend. I just put together a video from the 2015 race season, just a series of slow-motion startline launches of the various cars that were racing during that run. I got most of them, along with a couple Miatas. I was surprised to see that my launch was pretty much perfect (car 365, right around 55 seconds). What you're looking for is a ratcheting movement, where the tires are right on the verge of losing grip, but aren't free-spinning. I also found it really interesting to see how the different Subarus are front-bias or rear-bias, even those with identical gearboxes and differentials.

 

Also, Sean showed up with his Datsun for this event! Serious inspiration for me to get mine wrapped up.

[VIDEO]

[/VIDEO]

[S30Jay]

That's quite a project you have going on. I like sheet metal and fab work so keep the pics coming.

 

That 13b should move it out pretty well but there's something about the sound of a wound out L-series for me.

[drummingpariah]

That's quite a project you have going on. I like sheet metal and fab work so keep the pics coming.

 

That 13b should move it out pretty well but there's something about the sound of a wound out L-series for me.

 

I'd argue that all engines sound great, I just can't get over the sheer weight and size of the l-series. It's downright massive.

 

Compare the 13b:

 

to my l28et:

 

... and consider that now I have a rugged 5speed with common parts, and I've dropped the weight of the powertrain by almost 250lbs total.

[S30Jay]

For what your building the weight, and bias make sense. I wasn't trying to knock it, it'll be a fun and competitive chassis.

 

I wouldn't say the l is massive, its a straight six. Large in length compared to a rotary of course, typical for a straight six.

 

I put a 400 Chrysler into my dodge dart about ten years ago, despite being two cylinders shorter lengthwise it had a long cast iron water pump housing that put it similar in length to my l....but much heavier. Cast iron heads too. I guess I'm used to looking at bigger engines? Idk.

 

IMO there are many engines that do not sound good either, but that's a matter of taste as well. I haven't heard a Subaru yet with a decent note, my Impreza is no exception. But TO MY EAR a high strung L six is hard to beat in terms of a great exhaust note. Rebellos stroker engines top that list.

 

Anyway, I think you have a great build going and I'm looking forward to seeing the rest!

[drummingpariah]

For what your building the weight, and bias make sense. I wasn't trying to knock it, it'll be a fun and competitive chassis.

 

I wouldn't say the l is massive, its a straight six. Large in length compared to a rotary of course, typical for a straight six.

 

I put a 400 Chrysler into my dodge dart about ten years ago, despite being two cylinders shorter lengthwise it had a long cast iron water pump housing that put it similar in length to my l....but much heavier. Cast iron heads too. I guess I'm used to looking at bigger engines? Idk.

 

IMO there are many engines that do not sound good either, but that's a matter of taste as well. I haven't heard a Subaru yet with a decent note, my Impreza is no exception. But TO MY EAR a high strung L six is hard to beat in terms of a great exhaust note. Rebellos stroker engines top that list.

 

Anyway, I think you have a great build going and I'm looking forward to seeing the rest!

 

We definitely disagree on several points, then. In my world, nothing is sacred. I care about reliability, mass, and performance ... in that order.

 

• Reliability affects how much seat time I can have, which is the single biggest contributor to going faster. Mass affects everything:
• Engine mass affects every performance aspect of the car. A smaller engine is easier to maintain/replace, and a lighter engine allows the car to handle better, accelerate better, and brake better.
• Performance (power, or more specifically torque curve) affects the acceleration predictability. More power only benefits acceleration, and that's just a small piece of the 'go faster' pie.
• Sound doesn't make my car go faster. That means it doesn't even factor in. I find that any well-tuned engine sounds great. If I were going to stick with an inline 6, I'd probably source a lighter, more powerful aluminum BMW powerplant ... but it's still massive.
• I'm not a big fan of qualifying statements like, "for an inline 6" ... a big engine is a big engine. Wide tires are wide tires. Big brakes are big brakes. I'm building a pitfighter, not a bodybuilder.

If I were to take inspiration from any vehicle, it'd be Sherman's dwarf car that he hillclimbs. It's powered by a GSXR powertrain, weighs around 1200lbs, and makes nearly 200whp. It can out-handle practically anything, and is incredibly reliable. If I could easily make one street-legal, that's probably what I'd own.

 

It doesn't make any excuses. It isn't fast "for having so little power" ... it's just really fast, simple, reliable, and inexpensive.

 

 

In my mind, the advantage of inline 6 engines is that they can make so much power. However, I'd argue that if you need that kind of power, you're building a boring car (either it's too heavy, or you aren't building a car to use the power you have). To each their own and all that, but I really only get excited about cars that perform well when pushed hard.

[S30Jay]

That's quite a project you have going on. I like sheet metal and fab work so keep the pics coming.

 

That 13b should move it out pretty well but there's something about the sound of a wound out L-series for me.

There seems to be some miscommunication so I'll try requoting myself.

 

I'm NOT knocking your build, engine choice, or reasons for why your doing it. You don't have to sell me on it. Really.

 

One of the many things that make this forum great for me are the variety of datsuns and the range of buildups. From stockish to custom, swapped, bagged, race....its all here and it's all good. And I don't believe anybody is doing it the only right way.

 

That's how it's supposed to be.

 

So one last time, good luck on your build.

 

Jay

[drummingpariah]

I'm just explaining how I got to this point, why I did, and why I'm ignoring so many other viable build options. It's as much to reaffirm that I'm doing what I want to myself as to explain to you (or anyone else reading) what this is. I really think most people start changing things on cars without considering what they want the result to be. I'll convince you that there's a 'right way' eventually  :w00t:

[heclb4]

Hey sorry to be off topic, but what exactly did you do to the intake manifold in order for it to accept those "skinny" type injectors? Did the fuel rail provide enough "clamping" force to allow the injectors to seal after your modification which sat the injectors lower?

 

Im looking into purchasing similar injectors. Thanks

[drummingpariah]

Pallnet's clamps for the fuel rail against the intake manifold were designed for the l-series injectors, so they definitely didn't fit.

 

A little sheet metal and careful measurements produced some results ... (I had to take a second try at this)

 

... but basically, make some new fuel rail mounting tabs, make sure the manifold orings are snug, and you're in good shape.

 

In the end, I probably could've seated them slightly lower, but figured it's easier to remove more material later than it is to add material (I don't have an AC/DC tig welder onsite).

[drummingpariah]

Time to update for the end of Feb!

 

Today, I joined up with my friends Dave (click for his hillclimb build thread) and Ian (hillclimbs an NB Miata) and stopped at a local salvage yard on the way up to Vermont. I searched for a long time to try to find a decent front suspension setup, since the s30 fronts leave so much to be desired for my needs. I wanted the following:

• Match the rear suspension track width as closely as possible
• Get a double-wishbone setup, rather than the macpherson that I have now
• Keep myself open to common aftermarket options
• Retain maximum suspension travel
• Upgrade to vented brake rotors

The 350z/g35 (non-awd) front suspension solves all of these problems admirably. I get 12" vented rotors, floating piston calipers, a great front-steer steering rack, 5x114.3 hubs, and gorgeous double-wishbone suspension. Total cost: $1100. Roughly the same as a set of techno toy tuning coilovers (which are pretty much the best replacement available). I'm pretty happy with how things are looking.

 

Installation will be 'straightforward' for a custom fabrication job. That is to say that subframe pickup points need to be added to the s30 chassis such that the wheels are placed in the right locations and aligned with the body, and the upper mounts (damper hats and upper control arms) are mounted in the appropriate locations to retain stock-ish geometry. I decided that the conversion from front-steer to rear-steer would be a bit of a nightmare to cobble together, so I took the g35 steering column as well. That should ease the transition quite a bit, but it might require adding an extension to the steering shaft (the 350z/g35 really can't compare to the s30 in terms of firewall-to-crossmember-distance).

 

The new engine is in place. Just to illustrate my point of how large the l-series is, here's a size comparison.

 

Cage work is progressing nicely, as Joey ties in more suspension pickup points and triangulates the whole car. It's mostly 1.75" .095 DOM tube, but there's a fair amount of 1" or 1.25" for rigidity reinforcement. I want to ensure that everything outside of the crossmember points works as 'crumple zone' and that everything in the cockpit is treated as structural squishy-human-protection.

 

I'm really relieved with the seating position, for the most part. It's going to end up a few inches taller than it is to clear the floor and be above the sill bars, but I have gobs of head/leg room. I don't really expect anyone else to want to drive this beast, so that's even better than expected. The shifter location is perfect for that, and I found that I could even move the engine back a few inches to centralize the weight even more.

 

The problem with this setup, I found, is getting in and out. Especially after adding the FIA bars (semi-vertical bars that connect the bottom-front of the door to the top-rear of the windshield), the halo containment on the seat means my head has no way to comfortably get in/out of the car. Because it's a daily driver, I'm going to have to do some brainstorming to figure out how I'll solve that.

[Mattndew76]

Run a different seat for daily and install this one for racing?

[drummingpariah]

Run a different seat for daily and install this one for racing?

I don't love it, but that's what I've been thinking is my best option. I always find seat-swapping to be cumbersome and inconvenient, and doing it twice a weekend wearies me. Trying to explore other options before I commit to that.

[Duke]

Maybe get a different seat that doesn't have the side wings.  I don't think they area totally necessary, especially because you are going to be wearing a head/neck restraint.   I would imagine daily driving with those would be a total pain, firstly because of ingress/egress and secondly because it would be damn near impossible to check over your shoulder when changing lanes! 

 

I'm looking forward to seeing how this build develops, there is some pretty cool stuff happening so far.

[drummingpariah]

Maybe get a different seat that doesn't have the side wings.  I don't think they area totally necessary, especially because you are going to be wearing a head/neck restraint.   I would imagine daily driving with those would be a total pain, firstly because of ingress/egress and secondly because it would be damn near impossible to check over your shoulder when changing lanes! 

 

I'm looking forward to seeing how this build develops, there is some pretty cool stuff happening so far.

I could show you a few minor offs that would convince you that a halo seat is pretty necessary. The necksgen is good, but more safety is always better than less. I'll try changing the angle of the seat a bit, to make ingress/egress a little easier. As for shoulder-checks, that's exactly why I chose the cutaway sides (which are why the head enclosure comes so far forward). I may be able to modify another seat to have detachable wings, and that would be the best of all worlds ... but I'm not quite ready to decide yet.

[drummingpariah]

This weekend was a lot of math. I already knew that the g35/350z front subframe would be wider than the stock 280z subframe. I also know that the 240sx rear subframe is wider than the stock 280z rear subframe.

 

The stock front and rear subframes are designed to be the same width.

 

After math-ing, I came up with the following:

* Original hub-to-hub distance: 53"

* g35 hub-to-hub distance: 60.8"

 

That's 3.4" wider on each side

But wait! There's more!

 

The original Datsun wheels were 14x5 (15" diameter by 5" wide), and I'm bumping up to 17x8" (8" wide) for street wheels. I need to accommodate 17x10" race wheels, and my math suggests that I'll have around 6" of those wheels outside of the hub (per side). That's 5" more 'wheel' outside of the hub than stock.

 

At the end, this all means I'm going from a fender width requirement of 55" to 72", which is 17" wider, or 8.5" wider than stock, per side. This car-shaped thing is starting to show how ridiculous it really is.

 

My fender plugs just keep growing and growing. It's starting to get ridiculous.

[Lockleaf]

Insane. Yet very cool. Have you considered (or is it possible) narrowing the g35 subframe? That way you can change width but not affect any geometry.

 

They call the hub to hub measurement "wheel mounting surface" or wms.

[drummingpariah]

Considered it, but it doesn't really save me any work. I'd have to worry about modifying the steering rack (or tie rod arms) then, as well. The way this is going right now, I'm counting on my fabricator to get the mechanical/moving bits aligned and secured, and I can do most of the body panel fabrication from home. His shop is around 3 hours away, so I want to make the most of my time and empty garage while I can.

52 days remaining 'till the first race.

[Lockleaf]

Fair enough :)

[drummingpariah]

I suppose it's time to start talking about what's going under the hood. The current engine is a test mule, something I picked up off Craigslist that may or may not run. A friend of my fabricator happened to have a 13b that had been sitting on a shelf for a little while. I made an offer on it, and just **barely** squeezed it into my budget ... but this solves my "will it run reliably?" problem pretty completely. It's a ported 2rotor running on VEMS that's already been tuned, and is ready for whatever I want to throw at it ... as long as I'm throwing lots of fuel and oil at it.

 

 

According to the dyno results on this engine, it should be good for better than 350whp. Sometimes, you get lucky and the right deal comes along at the right time. This was my time.

 

It's going to take some time to get it in the car, get the harness wired in, and build the body harness for it, but I'm in full-on thrash mode now. 14 weekend-days left before the first event.

[soundboi]

i really dont know how these competition goes but, honestly if i was you, id look into swapping a s13 front suspension into the car, LCA , struts, brakes. Swapping the steering column and that suspension makes is really a task and Upper cradles allows camber to change into corners. which depending on how you look at it works or not.

 

the seat is extremely overkill and would make everything super difficult to get in and out. Mind you, my best mod to my car was the seats. It really completed the vehicle.

 

Spend some time on the fuel setup, get a decent lift pump and a good Surge and pump setup.

[drummingpariah]

Look back to this post for a good example of what our hills are like. The Super Chicken is probably the best example there, since you can see the suspension travel and that happened to be a record-breaking run (a little oil leaking into the turbo isn't a showstopper, of course).
 

i really dont know how these competition goes but, honestly if i was you, id look into swapping a s13 front suspension into the car, LCA , struts, brakes. Swapping the steering column and that suspension makes is really a task and Upper cradles allows camber to change into corners. which depending on how you look at it works or not.

I'm going to put this as delicately as I can, but there's no way around it: That's some of the worst advice I've heard in a long time.
 
In order to 'tune' a Macpherson strut, you need to change the control arm length. The control arm is a two-piece design on the s13, so you have a radius rod and the lower control arm, which sort of triangulate the bottom of the upright. You don't get any sort of fine-tuning, and unless you want to spend a lot of time fabricating, testing, and re-fabricating, you're never going to get much travel out of the suspension while maintaining a decent curve. In any event, you're stuck with a static curve with a single, fixed center.
 
The 'tuning' most wannabe-racers do involves moving the strut tower mounting point. All that does is adjust where on your static curve the car rests, and allows for ride height changes while maintaining some level of predictability in suspension behavior. On predictable surfaces, that's perfectly fine. Road racing, autocross, and drifting all rely on minimizing body roll and adjusting roll-center and center-of-gravity. Suspension travel isn't really a consideration. For hillclimbs (or tarmac rallies), longer suspension travel, and predictable handling throughout that travel, is a must.
 
It's not impossible to get long-travel Macpherson, but it's a whole lot more work than starting from double wishbone. I have a few friends who work at Vermont Sportscar (I bought my RX7 from one of their design engineers), and they almost exclusively build Subaru's Rally America cars. Subaru has long-arm Macpherson struts on the front two corners out of the box, and they're specifically engineered to work in a moderate-to-long suspension travel setup.

 
By comparison, the s13 has stubby, weak, heavy lca designs that are only effective under very specific conditions.

 
On top of all that, it'd be more work to put the s13 front suspension in than the z33 front suspension. The radius rods would require pickup points. The upper strut mounts would need to be very carefully placed to have a sane kingpin angle, camber curve, caster alignment, and static placement on the camber curve for a given ride height.
 
I like to think that I'm pretty open to other peoples' opinions, and I'm not just trying to tear you apart here. I feel obligated to pose an argument whenever I see advice like this, though. I see the front suspension on all of the s-chassis' as being the same as the ka24 engines:
A good choice of compromises for their original applications (a street car/truck), but inferior to most other options that are available.
 
It sounds like you're just recommending it because other people have made it work in the past. Don't idolize their results, appreciate that they were doing the best they could with what was available to them, and try to do the same. As far as I can tell, the Corvette or Z33 front suspension configurations are the best that's available to me.
 
 

I have no idols. I admire work, dedication and competence.

~Ayrton Senna
 

the seat is extremely overkill and would make everything super difficult to get in and out. Mind you, my best mod to my car was the seats. It really completed the vehicle.

Those wings are kind of a must in hillclimbs, even with a necksgen (or similar non-HANS neck protection device). HANS is absolutely worthless for side-impact. If I can find a way to use it (even if it's inconvenient), I will. It may come down to having a 'race weekend seat' and a 'work-week seat' or building some bolt-in wings, but neck protection is no joke.
 

Spend some time on the fuel setup, get a decent lift pump and a good Surge and pump setup.

I don't see a reason to waste time/energy/money on the stock tank, I already gave that away. I have the fuel cell and a pair of 120 Walbro's ready to drop in, when the time comes.

[Lockleaf]

Nice response. Clean and clear without being abusive.

 

Question for you.

 

What's your opinion of the z32/r32/q45 "third link" style modified double a arm suspension, if you're familiar with it?

 

It fascinates me just because it is odd.

[drummingpariah]

Nice response. Clean and clear without being abusive.

 

Question for you.

 

What's your opinion of the z32/r32/q45 "third link" style modified double a arm suspension, if you're familiar with it?

 

It fascinates me just because it is odd.

The z32/etc front suspension was apparently fantastic. I don't think I'd use it, because it's not extremely well-supported ... but I can't argue with the way it handles the pivot point. From what I've read (I haven't owned any of those cars) it virtually removed bumpsteer altogether. That's impossible with the more traditional double-wishbone/macpherson designs, you're always striking a compromise.

 

One of the biggest struggles with 'grassroots' motorsports is making sure a single person can handle all the logistics of racing for a season. That includes servicing, tuning, and upgrading, not to mention driving. That's what makes circle track cars so lucrative: Most parts are pretty standard, and you can just buy a handful of them and expect that they'll only need fine-tuning. Everything's simple enough that you don't need a whole team (but having one is extremely advantageous), and they're generally just built to take a lot of abuse.

 

On the other hand, you have cars like STi's or EVO's, which are extremely performant, but relatively high-maintenance, and you'll find that a single person has a hard time with just keeping them running reliably. I'm not saying that it can't be done, but a single racer could choose a simpler platform and focus on getting good tires and just learning to drive better (Miata would be a good suggestion) ... you'd end up with significantly better results overall.

 

With all that being said, that's why I chose the rotary engine. It's obscenely easy to service, is very well documented, and I like how small/light they are. The only thing on my car that's more complicated than it needs to be is the s13 rear subframe ... but that's what makes it so tune-able. It's a compromise that I agreed to take on for this build, but not one that I took lightly.

[drummingpariah]

No real update, but I can drop this off as a reference of scale. The engine will probably end up slightly farther forward than this, but I think it can safely be called 'mid engine'

[drummingpariah]

Because the new engine is going in, I now have the 'leftovers' of stuff that isn't going into the car in my shop. That means cleaning, organizing, and storing needs to happen (before the car shows up). This is unacceptable:

 

 

I started by shuffling some parts around, and making room in the 'engine room'. Because I know I won't using OEM EFI on this car, I decided to tear all the extras off of the assembled-spare 13b.

 

I started with this and a beer:

 

And ended with less clutter, and no beer. Here's the mockup housing assembly next to the 'assembled spare' block.

 

The turbo goes on the 'spare turbos' shelf. If there's any kind of market for it, I'll happily sell the harness/ecu/manifold/turbo/lines off to whoever is interested enough to make it worth putting them in a box. I have no idea what it takes to convert n/a to turbo, or if any of this is worth anything.

 

One interesting discovery I came up with is that these two engines apparently have different rotor housings. Otherwise, they appear to be identical.

 

One with no markings on top

 

The other with licensing markings on top.

 

As for accessories, here's one of the spare transmissions (I now have three turbo2 transmissions), and two of the intake manifolds (again, I have a total of three right now).

 

That emissions block-off kit is really disappointing. It's so thin that I can't use the stock studs. I can either draw up a DXF (just put these on a flat-bed scanner and scan them 1:1) and have Big Blue Saw cut out some proper plates, or pull those studs and use bolts instead. Generally speaking, I find that steel studs in aluminum don't come out as easily as I'd like. I'm leaning toward slightly girthier blockoff plates.