JAF's Locost (+221-Haynes/Custom-Miata)
Moderator: dhempy
Forum rules
Welcome to The Builders Logs. This area is for showing your current build/your completed car. Please only create a thread if you are currently building a car/showing off a finished project. Please do not create any other topics in this forum; any other subject should be posted in the correct forum. Please also only create one thread per user per project.
Welcome to The Builders Logs. This area is for showing your current build/your completed car. Please only create a thread if you are currently building a car/showing off a finished project. Please do not create any other topics in this forum; any other subject should be posted in the correct forum. Please also only create one thread per user per project.
-
- Posts: 164
- Joined: May 13, 2009, 6:04 pm
- Building: +221-Haynes-Miata
- Location: Missouri
JAF's Locost (+221-Haynes/Custom-Miata)
Long over due posting. Hopefully this will inspire some other of our completed builders to start a new topic on what they are doing to enjoy there completed build.
Fully licensed back in the fall of 2017 and doing what it was built for......AutoX. Clean as whistle, no scratches, and the rear fenders hadn't been punished by the cones.
Stay tuned for what I've been up to, and if you have a completed build please start a new thread and tell us how you've been enjoying your Locost.
Fully licensed back in the fall of 2017 and doing what it was built for......AutoX. Clean as whistle, no scratches, and the rear fenders hadn't been punished by the cones.
Stay tuned for what I've been up to, and if you have a completed build please start a new thread and tell us how you've been enjoying your Locost.
You do not have the required permissions to view the files attached to this post.
- Driven5
- Posts: 3274
- Joined: April 26, 2008, 6:06 pm
- Location: Under the weather. (Seattle)
Re: JAF's Locost (+221-Haynes/Custom-Miata)
Great work, and glad to see it out in it's natural environment.
Looking forward to the follow-up too.
Looking forward to the follow-up too.
-Justin
"Orville Wright did not have a pilots license." - Gordon MacKenzie
"Orville Wright did not have a pilots license." - Gordon MacKenzie
-
- Posts: 164
- Joined: May 13, 2009, 6:04 pm
- Building: +221-Haynes-Miata
- Location: Missouri
Re: JAF's Locost (+221-Haynes/Custom-Miata)
So what has the car been up to......AutoX, Cars-n-Coffee, and various car show events.
AutoX's have been been a little frustrating up until I got some new tires. The old Bridgeston RE71's had pretty much aged out since I bought them before the car was finished. Yokohama A052 are a good fit for our cars but I'm still giving up a ton of time without the favorite E-Mod or D-Mod tire of choice (Hoosier). The other big struggle is getting the suspension to cooperate. I'm on my second set of springs, which got my ride height where I wanted, but I know I haven't found the optimum alignment and/or settings to maximize my times. I'd also like to experiment with adding a front sway bar since I feel like have to much roll. Just look at this......
AutoX's have been been a little frustrating up until I got some new tires. The old Bridgeston RE71's had pretty much aged out since I bought them before the car was finished. Yokohama A052 are a good fit for our cars but I'm still giving up a ton of time without the favorite E-Mod or D-Mod tire of choice (Hoosier). The other big struggle is getting the suspension to cooperate. I'm on my second set of springs, which got my ride height where I wanted, but I know I haven't found the optimum alignment and/or settings to maximize my times. I'd also like to experiment with adding a front sway bar since I feel like have to much roll. Just look at this......
You do not have the required permissions to view the files attached to this post.
- Lonnie-S
- Posts: 5326
- Joined: October 24, 2008, 2:13 pm
- Building: V6 Powered Locost
- Location: Carlsbad, California, USA
Re: JAF's Locost (+221-Haynes/Custom-Miata)
Do you have any videos of the car in action? It looks great, by the way.
Cheers,
Cheers,
Damn! That front slip angle is way too large and the Ackerman is just a muddle.
Build Log: viewtopic.php?f=35&t=5886
Build Log: viewtopic.php?f=35&t=5886
-
- Posts: 164
- Joined: May 13, 2009, 6:04 pm
- Building: +221-Haynes-Miata
- Location: Missouri
Re: JAF's Locost (+221-Haynes/Custom-Miata)
Another long overdue update. Figure I'd share my painful experience of upgrading to a 1.8L Miata 7" diff.
Baseline build was centered around the 1.6L open diff. Picked because it came with my donor, it is the lightest option, and research had me convinced that there is no need for limited slip diff. Four years of fighting the dreaded one-wheel-peel coming out of slow corners, banging off the rev-limiter in 2nd gear, or up/down shifting between 2nd/3rd gears during Auto-X, and a buzzy 4K RPM highway drive made me rethink that diff choice.
Enter the solution. I bought a 3.63 Fuji diff with axles that only the Euro/Aussie MX-5's got.
First issue was getting the bigger diff to fit into my chassis. These larger diffs are a simple drop in swap in every Miata assuming you have the correct axles and driveshaft. Not the case when you make a skinny driveshaft tunnel that functions as the Miata PPF. These better diffs extend the driveshaft mating flange (nose) a few inches forward which makes the driveshaft a little shorter. You'll also need the specific flange yoke to mate with the new diff. I also needed to notch some tubing in the driveshaft tunnel, grind on some of the diff casting, and saw off ~0.5" of the diff casting right next to the PPF mounting bolts. Lastly I needed to make a drop out section of my chassis so that I could install/remove the larger diff. Pics to come.
First few drives were positive. LSD action made acceleration better out of slow corners. Gearing change from 4.3 to 3.63 was a game changer for Auto-X and highway drives. There is a reason why all higher HP Miata folks love the 3.63 and 3.9 diffs. Next few drives the diff started to make angry noises.
After a few weeks of bearing changes, pinion crush sleeve fighting, back lash setting, and multiple bottles of Redline fluid all I successfully did was make different types of diff noises. I pleaded with my driveshaft gut to recheck the balance of my driveshaft, which of course was perfect. We did notice some bluing/wear marks on the driveshaft yoke that goes into the transmission. So one new yoke and one new transmission tailshaft bushing later and guess what the results where? A different noise.
Getting late. Let's finish tomorrow.
Baseline build was centered around the 1.6L open diff. Picked because it came with my donor, it is the lightest option, and research had me convinced that there is no need for limited slip diff. Four years of fighting the dreaded one-wheel-peel coming out of slow corners, banging off the rev-limiter in 2nd gear, or up/down shifting between 2nd/3rd gears during Auto-X, and a buzzy 4K RPM highway drive made me rethink that diff choice.
Enter the solution. I bought a 3.63 Fuji diff with axles that only the Euro/Aussie MX-5's got.
First issue was getting the bigger diff to fit into my chassis. These larger diffs are a simple drop in swap in every Miata assuming you have the correct axles and driveshaft. Not the case when you make a skinny driveshaft tunnel that functions as the Miata PPF. These better diffs extend the driveshaft mating flange (nose) a few inches forward which makes the driveshaft a little shorter. You'll also need the specific flange yoke to mate with the new diff. I also needed to notch some tubing in the driveshaft tunnel, grind on some of the diff casting, and saw off ~0.5" of the diff casting right next to the PPF mounting bolts. Lastly I needed to make a drop out section of my chassis so that I could install/remove the larger diff. Pics to come.
First few drives were positive. LSD action made acceleration better out of slow corners. Gearing change from 4.3 to 3.63 was a game changer for Auto-X and highway drives. There is a reason why all higher HP Miata folks love the 3.63 and 3.9 diffs. Next few drives the diff started to make angry noises.
After a few weeks of bearing changes, pinion crush sleeve fighting, back lash setting, and multiple bottles of Redline fluid all I successfully did was make different types of diff noises. I pleaded with my driveshaft gut to recheck the balance of my driveshaft, which of course was perfect. We did notice some bluing/wear marks on the driveshaft yoke that goes into the transmission. So one new yoke and one new transmission tailshaft bushing later and guess what the results where? A different noise.
Getting late. Let's finish tomorrow.
You do not have the required permissions to view the files attached to this post.
-
- Posts: 164
- Joined: May 13, 2009, 6:04 pm
- Building: +221-Haynes-Miata
- Location: Missouri
Re: JAF's Locost (+221-Haynes/Custom-Miata)
Back to the story. Diff/Drivetrain noises. Didn't matter what i did they where always there. Luckily I came across a screaming deal on the favored Miata diff......a 3.9 Torsen diff. This was a known good one, unlike the suspect Fuji diff. Installation went good since I knew where to grind and the axles/driveshaft where interchangeable this they were both the larger 7" diff. Noise situation was greatly reduced for a few months then it reared it ugly head again. Something else had to be at play here. Enter in driveshaft angularity or phasing.
[youtube]https://www.youtube.com/watch?app=desktop&v=Idk3BVDVHq4[/youtube]
Turns out the I had about a 3-degree difference between the front and rear u-joints on the driveshaft. For whatever reason this wasn't an issue with the 1.6 diff, but the bigger Fuji and Torsen diffs resulted on a driveshaft that was a few inches shorter, which apparently was enough to trigger the vibration.
[youtube]https://www.youtube.com/watch?app=desktop&v=Idk3BVDVHq4[/youtube]
Turns out the I had about a 3-degree difference between the front and rear u-joints on the driveshaft. For whatever reason this wasn't an issue with the 1.6 diff, but the bigger Fuji and Torsen diffs resulted on a driveshaft that was a few inches shorter, which apparently was enough to trigger the vibration.
Last edited by jaf on December 6, 2023, 4:55 pm, edited 2 times in total.
- Miatav8,MstrASE,A&P,F
- Automotive Encyclopedia
- Posts: 8099
- Joined: December 22, 2006, 2:05 pm
Re: JAF's Locost (+221-Haynes/Custom-Miata)
You could put a camera behind the pax seat to film any vertical movement at the pinion flange under load, changing the driveshaft angle. Same thing for the trans mount. I don't remember what your mounts look like. I remember the 94-up na diff being less than 7 inch.
Found your build. I see the diff is solid mounted at the front so the only adjustment would be trans mount height. I expect solid mounting the diff would transfer more diff noise.
Found your build. I see the diff is solid mounted at the front so the only adjustment would be trans mount height. I expect solid mounting the diff would transfer more diff noise.
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12
-
- Posts: 164
- Joined: May 13, 2009, 6:04 pm
- Building: +221-Haynes-Miata
- Location: Missouri
Re: JAF's Locost (+221-Haynes/Custom-Miata)
Miatav8,MstrASE,A&P,F wrote:You could put a camera behind the pax seat to film any vertical movement at the pinion flange under load, changing the driveshaft angle. Same thing for the trans mount. I don't remember what your mounts look like. I remember the 94-up na diff being less than 7 inch.
Found your build. I see the diff is solid mounted at the front so the only adjustment would be trans mount height. I expect solid mounting the diff would transfer more diff noise.
The camera idea crossed by mind numerous times before I found the agularity differences. Funny you talk about the trans mount. I tried shimming it down but all I could bet was 1-degree better, and since the nose of the diff is solid mounted I figured the best method was just to fix it correctly. So off came the diff mounting brackets to re-weld them to make everything correct. If anyone is keeping track the nose of the diff ended up about 0.4" lower to get the 3-degrees out.
Pics of the new mount to get everything lined up properly and the drop-out link to accommodate the larger diff.
You do not have the required permissions to view the files attached to this post.
-
- Posts: 164
- Joined: May 13, 2009, 6:04 pm
- Building: +221-Haynes-Miata
- Location: Missouri
Re: JAF's Locost (+221-Haynes/Custom-Miata)
So another long over due update. When building the car I quickly settled on painting it white mainly because I've always loved white cars. There is nothing that looks better when all cleaned up. Fast forward a few years, add in some road rash, a few "oh crap" moments due to the tight space in my garage, way to many times clipping auto-x cones with the rear fenders, and that pretty white paint started to look a little old.
Before paint I had looked at vinyl wrap and plasti dip. Wrap was a no-go with all of my rivets and the cost of dip wasn't significantly cheaper than topcoat/clear and I still needed to do all of the panel prep and primer work. Well that's all done now so I bit the bullet and pulled the trigger on a DYC kit and got a few different shades of green. Tahitian Green was the winner in satin clear topcoat. So far I'm happy with the materials, equipment, the process, and end result. We'll see how it holds up from a durability standpoint. More pics to come.
Before paint I had looked at vinyl wrap and plasti dip. Wrap was a no-go with all of my rivets and the cost of dip wasn't significantly cheaper than topcoat/clear and I still needed to do all of the panel prep and primer work. Well that's all done now so I bit the bullet and pulled the trigger on a DYC kit and got a few different shades of green. Tahitian Green was the winner in satin clear topcoat. So far I'm happy with the materials, equipment, the process, and end result. We'll see how it holds up from a durability standpoint. More pics to come.
You do not have the required permissions to view the files attached to this post.
- horchoha
- Posts: 2436
- Joined: March 19, 2011, 10:22 am
- Building: locost super seven
- Location: Holden, Alberta, Canada
Re: JAF's Locost (+221-Haynes/Custom-Miata)
Wow, that color really 'pops', nice!
Perry
'If man built it, man can fix it'
"No one ever told me I couldn't do it."
"If you can't build it safe, don't build it."
Perry's Locost Super Che7enette Build
Perry's TBird Based 5.0L Super 7 L.S.O
Perry's S10 Super 7 The 3rd
Perry's 4th Build The Topolino 500 (Little Mouse) Altered
Perry's 5th Build the Super Slant 6 Super 7
Perry's Final Build the 1929 Mercedes Gazelle
'If man built it, man can fix it'
"No one ever told me I couldn't do it."
"If you can't build it safe, don't build it."
Perry's Locost Super Che7enette Build
Perry's TBird Based 5.0L Super 7 L.S.O
Perry's S10 Super 7 The 3rd
Perry's 4th Build The Topolino 500 (Little Mouse) Altered
Perry's 5th Build the Super Slant 6 Super 7
Perry's Final Build the 1929 Mercedes Gazelle
-
- Posts: 34
- Joined: September 16, 2013, 7:46 pm
- Building: Locost
- Location: St George Utah
- Contact:
Re: JAF's Locost (+221-Haynes/Custom-Miata)
That looks really good, much better than the last time I tried to use dip, hahaha. It was a disaster.
- JAMADOR
- Posts: 622
- Joined: November 6, 2020, 6:29 pm
- Building: FC RX7 Based
- Location: Spring, TX
Re: JAF's Locost (+221-Haynes/Custom-Miata)
That looks excellent, great choice.
1975 MG Midget
http://www.locostusa.com/forums/viewtopic.php?f=36&t=24382
13B Powered Rotus Geauxkart
http://www.locostusa.com/forums/viewtopic.php?f=35&t=20899
http://www.locostusa.com/forums/viewtopic.php?f=36&t=24382
13B Powered Rotus Geauxkart
http://www.locostusa.com/forums/viewtopic.php?f=35&t=20899
Who is online
Users browsing this forum: No registered users and 1 guest