The willingness to win, but remain unique. What should I build?

[HRH]

Okay, this should probably be in general technical, but here's the dilemma.  I've gone back and forth on selling the 510, and had finally decided against it.  Had my idea to build a mid/rear engine truck and race that, but eventually came to a different conclusion.  Here are the four things I'm taking into account:

 

1.  Wheelbase

2.  Track width

3.  Weight/center of gravity.

4.  Balance

 

Horsepower is just a question of how much you want to stick into a given motor.  Wheelbase matters for turn-ability of a given vehicle.  Track width matters a lot for stability, but is directly related to weight.  Look at a go-kart.  Center of gravity I'm not looking at so much because just about any vehicle I build for racing will have a fairly low center of gravity.  A 50/50 weight balance is always desirable, but close to it will work also.

 

Fast forward to the SCCA Solo National Tour.  I've been digging through results.  I found one 510 in EP class.  Finished tenth.  In SM class, the first 7 or 8 places are 240sx.  About 9th is Godzilla.  Yes, the 100,000 supercar is getting trounced on the national level.  All the cool ATESSA software and hp can't do shit against the fact the vehicle weighs 4000 pounds.  Our local fastest time of day cars are all 240sx'.  I believe Logr told me he had his coupe down to 2300 pounds.  About 300 pounds lighter than my shitbox hardbody chump/autocross truck.

 

What I've concluded is weight trumps all.  The less it weighs, the easier it is to move the object.  That is universally accepted.  Look at the vehicle that won the Grassroots Motorsport Challenge.  Carbon fiber aero body race car with a Hyabusa motor.  End of story.  Think it weighed 1000 pounds or something.

 

NOW, since we know we need something light, let's look at the 510.  My four door 510 weighs 2130 pounds or thereabouts with what little interior it has and a healthy iron block/aluminum head motor.  The disadvantage here is with more hp and bigger diffs, it's going to weigh pretty close to a 240.  But the 240 is fully 7.7 inches wider a track.  Not to mention the engine compartment is bigger, and the engine sits farther back between the strut towers.  I don't have any numbers, but I'll bet the 240 is better balanced than the 510.

 

BUT, I hate being a sheep.  You could argue I'm a retro-sheep since I have a 510 and that's what people drove in the 70's and 80's to win, but you all know what I mean.  I want to do something different.  Sure a '90 Civic Si hatch is a sure-fire way to win in ST class.  That's the easy way out.  As much as I'd like to do it my way, I also want to win.

 

So here's the question:  Given the information here, what do I build?  And how radical?  Do I cut out the firewall and move the motor way the heck back in the 510?  Do I get a title for the titleless hulk of a 240 I have on my back slab that I was planning on cutting up for parts for the 510?  Do I get a hardbody pickup, yard off the body, build a mid/rear pickup and then tube frame a body to attach plastic panels to, to essentially make it super light and well-balanced?  I'm curious what you at Ratsun think.  I'd like to think I can make a 240-killer 510, but that's a pretty big gamble given the statistics.  Of course, there is one really good thing about narrower cars in slaloms, they don't have to move as much.  Anyway, give it some thought, see what you think, and chime in!

 

 

Track widths Front/Rear Wheelbase

 

Hardbody: 54.9/54.5  Wheelbase 106

 

620: 51.4/50.8 Wheelbase 100.1

 

Miata: 55.5/56.2  Wheelbase 89.2

 

240sx: 57.7/57.5  Wheelbase 97.4

 

PL510:  50/50  Wheelbase 95.3

 

2014 Corvette: 62.9/61.7  Wheelbase 106.7

[q-tip]

A VG powered 510 would have a ton of grunt for auto crossing, hell the ka isnt too shabby either. In low speeds torque is king the more the better!!

[Komeuppance]

I'd rather see a 510 than a bro-40sx...

 

How big of tires will the class you plan to enter in allow??

 

-Robert

[HRH]

Well, motor swap automatically goes to Street Mod, and it's pretty much anything goes for the most part.  I can fit a lot bigger tires than the fenders will allow.  Think it's up to 10" wide rims.

[q-tip]

In that case who needs fenders!!! Stuff some 10's under it!!

[laotsu]

body-swap the 510 onto a Miata?

[Gary]

is a different engine an option? na rotor will help keep weight low and further back (can cut less of the firewall too if you still wanted to do that) or bike engines, or even something like a 4AGE. i dont reckon thered be a downside to a 510 over a 240 with a little work in balance

 

theres always going to be quicker out there, you sure you want to focus hard on winning and not just having a blast? i mean sure its fun to be quicker than x but theres a point where you can take things too seriously and probably not have as much fun

[yellowdatsun]

If you want to be unique, don't build an SR20 510.

 

We've got one 510 with a VG30, are building a second, and the track 510 has a VG34 built for it. Sooo you can tell we like the VG's. Highly under-rated if you ask me. The guys who have them love those engines. The torque is awesome. Due to them only being 3 cylinders "long", they can sit further back than the L-series, so even though they weigh more, the distribution is great.

[datzenmike]

Keeping It Stock

Z24 with L head will be mistaken for an L16. Keep and use your 4 speed it's light and you'll never see 5th anyway. Get the R-180 from an early 720 and you'll have 4.375 gears. With some digging you could find 4.625 gears for it too. Lincoln Locker for sure. The 510 isn't too bad front to rear bias anyway. Maybe move it back a foot?  Relocate the battery over the axle.

 

Motor Swap

VG30S small four barrel. Machine a dizzy from a z car. Definitely move this back as it adds about 150 extra pounds to the front. Use a D21 5 speed they are the shortest 71C.

[HRH]

Well I talked with my Datsun guru for a bit.  He got me back to square.  Basically, as he informed me, even the best, fastest time of day racers we have at our local autocross, don't have the deep pockets or the commitment to win on a national level.  If you look at the money they have in a national winning car, he's right.  The 510 does have a problem of track width.  Without box flares, you can't get it wide enough to corner as fast as a comparable 240, at 8" wider track stock.  Basically to be in the ultra-elite competitive, you need to start changing the 510s suspension geometry fairly radically.  Whereas they're fast and nimble and kick-ass for 99%, that extra 1% is what makes or breaks a winning car.  Back in the day, it was the pinnacle of evolution nearly and thus why it won fairly regularly.  Nowadays, you don't see many winning except in vintage classes.

 

So, I have some thinking to do about what I want to achieve and how much money I want to achieve doing it.

[thatguy]

Speed is money, how fast do you want to go?