LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently Sat Oct 25, 2014 4:42 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 221 posts ]  Go to page 1, 2, 3, 4, 5 ... 15  Next
Author Message
PostPosted: Wed Jan 18, 2012 3:57 am 
Offline

Joined: Fri Sep 30, 2011 4:08 pm
Posts: 241
Location: Portland, OR
After the requisite planning and contemplation phase I've acquired the big parts for my build and i'm ready to kick off my build.

I started by buying two parts cars - an '01 miata for the front and rear suspension parts & rear drive parts and an s2000 for the f20c and its 6 speed trans. After parting out the two cars I was basically able to break even with the suspension and engine parts helping to keep the cost of the project down a lot.

I'm starting with a buddies partial frame, it's BEAUTIFUL and obscenely straight. I'm going to make a few changes - he intended to put a bmw straight 6 in the bay so its setup for a different engine than i'll be using.

I've done a few build threads for various projects before notably my e36 m3 ls1 swap

Miata leaving
Image

S2000 leaving
Image

f20c dropout
Image

picking up the frame
Image

Rented a spot in an old race car builders shop to get access to fab tools and get out of my two car garage, got all setup
Image

the frame setup on my 'table' - the friend I bought the frame from used a similar setup and highly recommended it as a good build table option becuase it can be welded on and is very flexible, I picked the whole setup up for about a 100 bucks and instead of spending hours building it I had it together in about oh 5 min.
Image

_________________
My Build thread: F20C powered Autox & track toy


Top
 Profile  
 
PostPosted: Wed Jan 18, 2012 1:18 pm 
Offline
User avatar

Joined: Thu Jul 07, 2011 12:17 am
Posts: 115
Location: Sandy, OR
Image

_________________
Regards, Ron


Top
 Profile  
 
PostPosted: Thu Jan 19, 2012 1:11 am 
Offline
User avatar

Joined: Fri Nov 13, 2009 8:43 pm
Posts: 455
Location: Portland, OR
Awesome dude. I envy your stripping of two donor cars: I only got the satisfaction of the Miata.

I'm in the neighborhood. Please let me know if I can lend a hand somewhere.

What're the dimensions of the chassis? It looks slightly different than the "book" or +442 chassis.


Top
 Profile  
 
PostPosted: Thu Jan 19, 2012 1:38 pm 
Offline

Joined: Fri Jan 07, 2011 10:47 am
Posts: 74
Location: Bethlehem PA
Best of luck with your build.

I checked out your bmw write up. Nice Job:)

_________________
Chris White
Locost 7 type 1 power and a rear transaxle
Lotus Elise
Nissan Titan
Ford Escape Ecoboost
http://www.locostusa.com/forums/viewtopic.php?f=35&t=13200


Top
 Profile  
 
PostPosted: Mon Jan 23, 2012 2:12 am 
Offline

Joined: Fri Sep 30, 2011 4:08 pm
Posts: 241
Location: Portland, OR
some very minor updates since I forgot to bring my garage camera over to the new shop area

I was able to get my "table" setup properly and modified to fit my needs

I then got the frame setup on it again and checked for level front & back & side to side - spot on almost the first time. I centered it on the table from the existing center lines on the chassis and tacked it to the table nice and center & level.

then I sat the miata diff up there to try and decide if I liked it or the s2k diff better - the s2k diff is smaller and I like it's mounting setup better but supposedly it isn't as strong...

Image

I also pulled apart the miata front & rear subframes to get me to the interesting pieces
Image
Image

and despite it not looking like it I pulled a bunch of unneeded items off of the motor - the coolant hoses, the AC and some emissions stuff. I'll need to either loop or cap the heater core lines for cooling depending on how the water pump prefers. I also pulled the secondary air intake off and plugged that with a plate.

Image

next up is fitting the motor in the engine bay to figure out what modifications will need to be done in that area

I also need to start fabbing the rear up. my intention is to mimic the miata rear pickup points. I received some suspension brackets from Mr Jack @ Kinetic so I"ll have those to use. I have a few more fiddles within my suspension analysis program to make and then i'll post those up for a review here.

_________________
My Build thread: F20C powered Autox & track toy


Top
 Profile  
 
PostPosted: Mon Jan 23, 2012 2:16 am 
Offline

Joined: Fri Sep 30, 2011 4:08 pm
Posts: 241
Location: Portland, OR
mattrogers wrote:
Awesome dude. I envy your stripping of two donor cars: I only got the satisfaction of the Miata.

I'm in the neighborhood. Please let me know if I can lend a hand somewhere.

What're the dimensions of the chassis? It looks slightly different than the "book" or +442 chassis.


I don't know if envy is the right word, that s2k was a PITA to take apart, so much more complicated than the very easy miata.

chassis dimensions are at the front 26 3/4 across the top and 21 1/4 across the bottom - 15" tall - along the back of the frame 46" and somewhere shy of 8' front to back right now.

front suspension rear tubes are 9 3/16" behind the front of the chassis.

You're welcome to swing by and take a look as I get some more progress in - i'd love to discuss pain points


cwhite wrote:
Best of luck with your build.

I checked out your bmw write up. Nice Job:)


Thank you sir!

_________________
My Build thread: F20C powered Autox & track toy


Top
 Profile  
 
PostPosted: Mon Jan 23, 2012 3:37 am 
Offline
The voice of reason
User avatar

Joined: Thu Jan 10, 2008 4:47 pm
Posts: 5788
Location: Massachusetts
Quote:
the s2k diff is smaller and I like it's mounting setup better but supposedly it isn't as strong...


This car will have so much less weight on the tires that the diff strength is likely much less of an issue. If you have half the weight on the tires, you'll only be able to put half the torque thru the diff...

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
 
PostPosted: Mon Jan 23, 2012 11:59 am 
Offline
User avatar

Joined: Sat Apr 26, 2008 6:06 pm
Posts: 2204
Location: Under the weather. (Seattle)
Tongboy wrote:
the s2k diff is smaller and I like it's mounting setup better but supposedly it isn't as strong...
Not as strong how? From what I recall, in the Miata world it's generally accepted that the S2k differential is based on the 1.8L Miata differential, but actually offers a stronger drivetrain due to a shot peened ring and pinion and its use of larger stub and half shafts. I know there were some issuse with the case strength in the AP1 cars, but remember too that the S2000 is both heavier than a Miata and has forced induction Miata power. Off hand I don't know of any direct comparisons to validate whether the early case is physically any weaker than the Miata ones. And speaking of weight, don't forget how much less (~50%?) of it the differential will have to fight in this car. Especially considering the stated purpose of this car, I personally would probably be looking moreso at which setup is lighter...And wouldn't forget to post the weights for the others on this site who have inquiring minds.
:cheers:

_________________
-Justin

Also follow my build on blogspot, tumblr, or instagram and twitter (GarageOdyssey)


Top
 Profile  
 
PostPosted: Mon Jan 23, 2012 9:47 pm 
Offline

Joined: Fri Jan 21, 2011 7:51 pm
Posts: 3
Nice another F20C locost.
I'll be watching this thread with interest.

_________________
Lotus Elise
F20C Locost


Top
 Profile  
 
PostPosted: Tue Jan 24, 2012 3:05 am 
Offline
User avatar

Joined: Sun Jan 06, 2008 1:29 am
Posts: 20
Location: Portland, OR
Hi Tongboy, good to see another Portlander building a seven. I finished mine when this forum was just getting started so I never developed a build blog of my car. But circumstances have changed and soon I will start one to document the changes I am making to satisfy a local racing organization that questions the safety integrity of these cars for track days. Which brings me to why I'm here. When I saw your title stating you plan on a track toy be advised that rollbar requirements vary widely depending on who you participate with. Since you are at the beginning stages I would start thinking about the rollbar now and incorporate it into the chassis before it becomes nothing more than an after thought like they more or less are now with the original design.

It seems most race sanctioning bodies want the main hoop to start on the lower frame rail then up to the required height and across the cockpit to the opposite side lower frame rail then tie in your upper frame pieces to that hoop. If I were to build another car that is how I'd start. If you look around on this site there are some good examples of this type of construction.

I have a friend with an Ultralite that has the S2000 engine and trans. I think it's a good choice for these cars. We should have meet up with all the builders and owners in the Portland area like they're doing in other areas. Good luck with the build and if I can help with any questions feel free to contact me.

Jim Larfield


Top
 Profile  
 
PostPosted: Tue Jan 24, 2012 11:11 am 
Offline
The voice of reason
User avatar

Joined: Thu Jan 10, 2008 4:47 pm
Posts: 5788
Location: Massachusetts
Jim, do you think your local folks also require a tall front hoop?

I think it makes sense to design a roll cage that matches the passenger compartment of a Seven or Locost and then build the car outwards from there. It minimizes any weight or space penalties and just seems to make sense, the tubing is there just use it...

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
 
PostPosted: Tue Jan 24, 2012 12:04 pm 
Offline
User avatar

Joined: Mon Apr 12, 2010 5:40 pm
Posts: 1858
Location: san francisco bay area
Here's the club brother Phillip is in. .... He tells me that they have a couple of Locost7s. (hmmmm plural of Locost7. .. :? )
http://www.eescc.org/

_________________
"There are times when a broken tool is better than a sound one, or a twisted personality more useful than a whole one.
For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett


Top
 Profile  
 
PostPosted: Tue Jan 24, 2012 11:51 pm 
Offline

Joined: Fri Sep 30, 2011 4:08 pm
Posts: 241
Location: Portland, OR
Good info all around guys - I'll get back to it when I have a moment but I did want to provide the s2k diff weight as someone asked about it

Image

69lbs 5.4 oz on my new & very accurate postal scale - this is drained but still with the axle cups & rear mount piece (that rear mount doesn't weigh much...) I'll check it again after I pull the axle cups.

_________________
My Build thread: F20C powered Autox & track toy


Top
 Profile  
 
PostPosted: Wed Jan 25, 2012 2:01 am 
Offline

Joined: Fri Sep 30, 2011 4:08 pm
Posts: 241
Location: Portland, OR
horizenjob wrote:
Quote:
the s2k diff is smaller and I like it's mounting setup better but supposedly it isn't as strong...


This car will have so much less weight on the tires that the diff strength is likely much less of an issue. If you have half the weight on the tires, you'll only be able to put half the torque thru the diff...


I'd agree that the weight is massively reduced on the smaller car but I would also say that by stepping up the size and adhesion limits of the tires that it isn't directly half the torque pushed through the driveline. a hard prosolo drag launch on R comps even in a 1400lb car is going to put more stress on a diff than hard street driving on 350 wear tires on a stock car.

Driven5 wrote:
Tongboy wrote:
the s2k diff is smaller and I like it's mounting setup better but supposedly it isn't as strong...
Not as strong how? From what I recall, in the Miata world it's generally accepted that the S2k differential is based on the 1.8L Miata differential, but actually offers a stronger drivetrain due to a shot peened ring and pinion and its use of larger stub and half shafts. I know there were some issuse with the case strength in the AP1 cars, but remember too that the S2000 is both heavier than a Miata and has forced induction Miata power. Off hand I don't know of any direct comparisons to validate whether the early case is physically any weaker than the Miata ones. And speaking of weight, don't forget how much less (~50%?) of it the differential will have to fight in this car. Especially considering the stated purpose of this car, I personally would probably be looking moreso at which setup is lighter...And wouldn't forget to post the weights for the others on this site who have inquiring minds.
:cheers:


From what i've been able to find the s2000 diffs aren't terrible for stock power levels but they tend to break whatever the bearing holders are that hold the diff into the casing (like lower rod arms breaking, i just don't know the proper name) they sell a few kits to strengthen it but the miatas don't have that as a failure point - they'll toss axles and shred gears, I suppose it's six and a half dozen either way. I do agree they certainly hold more power factory spec to factory spec by far. both setups deal with roughly the same torque output from the factory FWIW.

Total weight of the diffs isn't something I thought of - that's a good point. I'll have to throw them both on the scale for equal comparison. I also want to find out if the driveshafts are compatible - the s2000s are wider than i'd like to use but I could work with them - i'd then have to check if the outboard CVs are compatible to the miata spindles as well...

homebrew wrote:
Hi Tongboy, good to see another Portlander building a seven. I finished mine when this forum was just getting started so I never developed a build blog of my car. But circumstances have changed and soon I will start one to document the changes I am making to satisfy a local racing organization that questions the safety integrity of these cars for track days. Which brings me to why I'm here. When I saw your title stating you plan on a track toy be advised that rollbar requirements vary widely depending on who you participate with. Since you are at the beginning stages I would start thinking about the rollbar now and incorporate it into the chassis before it becomes nothing more than an after thought like they more or less are now with the original design.

It seems most race sanctioning bodies want the main hoop to start on the lower frame rail then up to the required height and across the cockpit to the opposite side lower frame rail then tie in your upper frame pieces to that hoop. If I were to build another car that is how I'd start. If you look around on this site there are some good examples of this type of construction.

I have a friend with an Ultralite that has the S2000 engine and trans. I think it's a good choice for these cars. We should have meet up with all the builders and owners in the Portland area like they're doing in other areas. Good luck with the build and if I can help with any questions feel free to contact me.

Jim Larfield


Hi Jim! Thanks for the great information. I'd love to chat rollbar design with you as I really am at an ideal phase in the project. My intention was to run a 5 point rollbar and try and get as much rear arm angle as I can. And then run a seperate full cage that bolts up toward the windshield for wheel to wheel racing. You've got me thinking about maybe a more permanent main hoop and a front hoop integrated into the cowl area with the appropriate ties. I'm trying to meet the SCCA road race regs which will get me the scca solo2 rolled in and be meaningful when chatting with the NASA guys if I head down south for any of their events. I'm told conference runs somewhere near the scca specs but I haven't been able to talk extensively with anyone there yet. Any experience you'd be willing to lend would be much appreciated.

oldejack wrote:
Here's the club brother Phillip is in. .... He tells me that they have a couple of Locost7s. (hmmmm plural of Locost7. .. :? )
http://www.eescc.org/


I've run an autox with those guys, very friendly and welcoming folks. I'd like to run their next hillclimb if I can get out of design paralysis and get moving forward.

I know a friend of a friend with a crazy powerful LS-powered locost car that runs with them on a semi-frequent basis.

_________________
My Build thread: F20C powered Autox & track toy


Top
 Profile  
 
PostPosted: Wed Jan 25, 2012 3:26 am 
Offline
User avatar

Joined: Sun Jan 06, 2008 1:29 am
Posts: 20
Location: Portland, OR
Quote:
Jim, do you think your local folks also require a tall front hoop?

I think it makes sense to design a roll cage that matches the passenger compartment of a Seven or Locost and then build the car outwards from there. It minimizes any weight or space penalties and just seems to make sense, the tubing is there just use it...

Marcus, no they don't require a tall front hoop, but what they seemed to be concerned with is the rollbar collapsing straight done in the event of a rollover. They question whether there is enough structure underneath supporting the rollbar at it's high mounting point. The problem is that most of the people in this racing organization don't understand tube frame/space frame construction and how it gets it's strength. The majority of them race street based production cars. Purpose built race cars have taken a huge decline with this organization in recent years. When I pointed out to them that older formula fords (that still race under ther sanction) had there rollbar welded to the upper frame rail, they were quick to use the homo word as in homologation. My car was not homologated therefore they could not take a chance in the event of a crash. The current board of this organization likes to deflect any responsibility/liability to any other racing organization that they can. For example if your cage had an SCCA stamp on it then it automatically qualifies with them even though there minimum tube diameter is 1.5" and .120 wall. That's if you're building a car to only race in conference. I believe SCCA is 1.375" and .085 wall for the lightest weight car.

I could go on with my frustrations with this group (International Conference of Sports Car Clubs, ICSCC, of simply known locally as Conference) for a long time but this isn't the time or place. I'm not trying to race with them just participate in the HPDE events they usually have the Friday before they're race weekend.

Tongboy, PM me with contact info and I'll tell you what I have learned about the rollbar/ rollcage issue and hopefully send you in the right direction if I don't have the answers.

Jim


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 221 posts ]  Go to page 1, 2, 3, 4, 5 ... 15  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY