Datsun Roadster: 2020 Challenge Build

maschinenbau said:

In reply to Robbie (Forum Supporter) :

All I did was search that Worldparts catalog you linked above, then found the equivalent US Cardone part number with some google-fu, plugged that number in to Rockauto to find the makes and models, then compared the specs and pictures on Rockauto of axles for Ion Redline vs axles for early Saab 9-5. They look awfully similar so I hope it works out! They must be very similar trans because it's the same axle left vs right just like with the Ion/Cobalt, even for both Saab engines the 2.3 and 3.0 V6. So you can probably junkyard it too. There was one other match that was only 1" longer, I think for Saturn Vue, Equinox, Torrent, etc. 

You're the master. I did the same thing but must've missed the Saab 9-5 axle somehow. Thank you thank you thank you!!!

I looked closely at the vue, equinox, torrent, and those have an even bigger axle nut so I am curious if their outer spline is the same or if the shaft diameter is bigger.

Nevertheless, I believe this is going to work after I hammer off the abs ring!

I also checked the other side last night and the cobalt axle was perfectly in the middle of the range. Exactly what I was trying to do. So at this point I don't know what I did to screw up the right and not the left. My best guess is I centered everything and set the chain angle line and then decided to shorten the chain a bit. 

Great way to end the week!

Btw, the 9-3, 9-5, cobalt, ion, and many other ecotec fwd motors use a version of the f35/f40 manual transmission. But I don't think they are all plug and play or swappable with each other without work.

SWEET!

Wow I'm so glad that worked out! Hopefully now you get more than a few seconds of seat time. Can't wait to hear how the new suspension feels.

Nice!

Lost about a week thrashing on the tow vehicle, but I did get some done on fdat.

Final assembly revealed a slight interference between the cobalt abs sensor thingy and the Saab 9-5 outer CV joint. 

Luckily there was just enough room to grind it off with my angle grinder and I didn't have to spend hours with the Dremel. There's actually a lot of metal under that plastic.

Aaaaaaaaaaand, I made it to a local autox to repeat my shakedown, but this time with correct length axle.

You're right up there with some seriously fast cars! Did it survive? Everything go okay?

That's me! Faster than a Tesla, cayman S, and that's a lotus Elise just below the cayman.

However looking at results is less important that my own impressions. 

1. The car now drives amazingly. Before it beat the crap out of the driver, and was really hard to control. Now, it absorbs bumps like they aren't even there. 
2. Turn in is still incredibly sharp and responsive.
3. Seems that the car likes to drive at a pretty significant slip angle. This may be the tires. But the good news is it is very easy to control, both with the pedals and the steering wheel.
4. Couldn't feel any weird acceleration effects from the crooked diff. However, as nonack predicted the center rear brake can lock the inside rear tire on trail braking sweepers, which I think was having the effect of killing the engine momentarily. But the engine comes right back to life when the wheel moves again and there is so little rotating mass in the whole thing it didn't seem to upset the car at all. CB recommended that I loosen the rear shock rebound to let the tires stay in contact with the ground better. This makes a lot of sense to me and I may try it.
5. My tires were not warming up. My fastest run was one I spun the rears big-time on launch, which adds to the thinking my tires may not have been warming up. Hot lapping or multiple drivers could really help.
6. I tested tire pressure just a tad. First 5 runs I ran at 11psi. 5th run was my fastest of the day. Runs 6 and 7 I went down to 9psi all around, and run 6 felt faster but I looped it right at the end. Run 7 was 2nd best time of the day but I know I messed up the very first turn so it's a bit hard to compare. Good news is the tire pressure didn't make a HUGE change, which hopefully means the car isn't super sensitive to it.
7. This course was tight and relatively slow, but there was both a good 270deg lefty sweeper and a good 180deg righty sweeper due to intelligent course design. Also the lot was poor asphalt and very gravelly most places. This made it hard to leverage fdat's strengths in straight line acceleration and slaloms. 
8. It was a joy to drive the car with the throttle in the sweepers.
9. Had a coolant issue after first run because the bonehead prepping the car installed a hose clamp incorrectly. I also think I had a brake reservoir cap on crooked which leaked some brake fluid at first. 
10. The car still sounds the business. 

maschinenbau said:

You're right up there with some seriously fast cars! Did it survive? Everything go okay?

I'm going to get it up on the lift and inspect some, but no major mechanical issues at all. 

This Challenge is gonna be so f'ing awesome 

Great result.  Glad the rear diff arangement works and more thrilled that the revised suspension design actually doesn't suck. 

That was a ..  ..  Concern.. as I've never designed a trailing arm before.  

For inspection I would remove the rear shocks and just make sure the eyes look fine on the top and bottom.  The suspension movement and the way we mounted potentially puts a lot of side force on the rigid eye.  

It sounds maybe like the goal of making Fdat a comfortable useable car was reached.  

Can't wait to give this a go at the Challenge.

Bravo.

There are going to be so many amazing cars at the challenge this year. I love this thing and I'm excited to see(read) how it performs. The rear suspension is just so flipping cool!

it will be my honor and privilege to beat such a quick car. is this the right thread for that? ;-)

In reply to AngryCorvair (Forum Supporter) :

I will try to remain humble watching y'all's battle for 2nd place

Quick inspection last night didn't see any issues but will disassemble further. 

Did find that I lost one of my muffler bracket screws. Doh. Easily replaced however and probably gonna add some loctite...

Starting final challenge prep punch lists 

AngryCorvair (Forum Supporter) said:

it will be my honor and privilege to beat such a quick car. is this the right thread for that? ;-)

No this is a thread of truth. For threads of delusion, search "monzora".

maschinenbau said:

In reply to AngryCorvair (Forum Supporter) :

I will try to remain humble watching y'all's battle for 2nd place

Can't see out of rear of your car... Must be saying you'll watch out of your windshield from behind?

In reply to nocones :

Yes, the goal of making fdat a comfortable and useable car absolutely nailed. Thanks again for all your help!

The press is on!

And here's the corner weights, math was from me adding and subtracting lbs from the heavy space saver wheels on the car right now back to the race wheel weights. 

I still have a couple items to put back on the car, but none that heavy. Going to be just over 800lbs in race trim I think. I also think that means that adding suspension didn't add any weight overall - which is a significant win in my book!

Can't wait to see this car in a week!  

Awesome!

Ok, most stuff checked off the list. 

I found out that if I switch from the higher steering ratio tie rod holes to the lower ratio holes my alignment tends to toe out a lot. 4.5 full turns of the tie rod will get back to original toe setting. Right side is easily adjustable.

Put the floor and diffuser back on and almost all the original rivet holes just lined back up. Nice. I did have to move the hole that allows for chain sprocket space.

More, after my son's baseball game.

It's time for the F5 brigade gentlepersons.  

Ok, I've also done a really poor job of tracking my hours as the rubber has been hitting the road here. But since the last update I've done 3 big weekends of work with some in between too. I was at 812 before I'm going to say I'm at 850 now.

As I did the nut and bolt to check tightness on everything in the front and rear suspension as well as other critical fasteners (like engine mounts), I put every tool I used in a pile. Here it is for future reference for me.

Also, my son and I have been watching lots of videos on YouTube recently (more on that later), and he has been dying to have me let him try spray painting stuff. So I had him do my diffuser. I asked for a big white area and then he wanted to do some blue and silver too. Then, I drew a diagram.

I call it: "how to make a chain-drive, limited-slip, independent, semi-trailing arm rear suspension on a challenge budget". Also, I think I count parts from 7 different vehicles. Miata, Chevy van, Saturn ion redline, Cobalt SS, Saab 9-5 (oops), CBR600RR, and race car rotor and caliper. 

Finally, it was time to address the vehicle's exterior. I spent a long time removing old sticker goo - and I think I got some of the clear coat off with it. Doh.

Since we are in charge of our own number now, I took some of my remaining red scraps, and did numbers. And 8 letters "GTU$" twice. 

Now, remember how I've been watching lots of YouTube videos with my son? A few months ago Nocones gave me the idea to cel shade the car. My son is a really good artist and loves comic books, so I talked to him about it and he loved the idea. We've been watching every YouTube video we can find on cel shading cars. About a week ago I mocked some up with tape and it looked ok, so we decided to go for it. 

I held my breath and handed him the paint markers. He knocked it out of the park!

He did most of it, with me standing there watching in awe. He just sees things differently than me. I did do some of the lines, but he was much better at it than I was so I let him get after it. 

As I'm standing there watching him work, he goes " you know, dad, mistakes make it look better because a drawing isn't perfect." I guess he's a better philosopher than me, too.

Took him about an hour total, and I think the car looks incredible. We tried to save some space for stickers, and in the end I had him sign the car too. 

He won't be able to attend the challenge this year (school), but I really hope we can put on a good show to match the artwork!