LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently March 29, 2024, 2:39 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 37 posts ]  Go to page 1, 2, 3  Next
Author Message
PostPosted: October 18, 2020, 5:01 pm 
Offline

Joined: October 18, 2020, 4:28 pm
Posts: 17
Hi!

Have been lurking on here for years, playing with the idea of building something and now I've decided to just go ahead and do it. This project has been kicking around in my head for 8 or 9 years and has gone from motorcycle on four wheels, to land speed racer to GP car and everything in between.

I am building a Buick 215 powered single seater in the style of the 50's front-engined Grand Prix cars, but smaller and hopefully lighter. I have just bought the engine and am having a Super T10 built to the right gearing for the 3.08 8.8" rear end out of the Mustang SVT Cobra. It will be sitting on rather tall 185/80/15 Dunlop Sport Classic tires.

I know sitting on top of the driveshaft isn't a great choice in terms of CG, but I will be dry-sumping the engine to get it in lower. Also the track width will be wider than common with Sevens and the wheelbase longer. I'm not building this to any rules other than the sensible safety regs for roll bars and tubing thickness for the chassis. This will be a street legal canyon carver and is only supposed to be fun. It'll be quick enough either way, it's about the experience. The idea is not to make the fastest car out there (which it wouldn't be) but something that is enjoyable to drive and controllable. Although with 240hp on tap it probably won't be a slouch.

I plan on going with a tubular space frame and a pushrod actuated double wishbone suspension front and rear.

The whole car will be built in CAD first before I pick up a welder. Obviously a plan never survives the first contact with the enemy, but I'd like to have the avoidable headaches (FEA, mounting points, parts interference etc.) figured out before I start building.

The body will be composite at first and later consist of hand formed aluminum panels. It shouldn't be too hard to make a buck from the CAD files.

I'll be adding pictures as the parts come in and I scan them for CAD so I can lay out the chassis. I'm on a very ambitious time schedule (driving it by Feb/Mar without the body), due to my job I can invest several hours a day and the car would be assembled at my workplace as well.

I look forward to being part of this awesome community, there's just so much knowledge in these forums!

Always open to other people's input and ideas, I generally don't take offense so don't hold back!

Alex


Top
 Profile  
Reply with quote  
PostPosted: October 18, 2020, 11:49 pm 
Offline
User avatar

Joined: July 29, 2006, 9:10 pm
Posts: 3160
Location: Oregon, usually
Hi Alex, welcome aboard, this seems like just the sort of project that the Building Non-traditionally forum was started for.

_________________
Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles


Top
 Profile  
Reply with quote  
PostPosted: October 19, 2020, 12:10 am 
Offline
User avatar

Joined: November 11, 2013, 4:47 am
Posts: 1617
Location: No. Nevada
Similar to one of my own Down The Road projects, but mine is planned to be a bit less power.
1.0 3-Cyl. Suzuki and Samurai trans. I have a Buick Apollo 4-lug rear that may be used.
Being less ambitious and cheap, or just short on time, I am looking for used Sprint Car body pieces.
Failing that I'm keeping an eye out for vintage steel fenders to cut and splice for the rear body.
Front body is simple enough to hand-form.

The BOP/R engines are one of my favorites, had a wild one in my Noble P4 replica.
Looking at building another milder version for my Locost 442 build.

Please post your CAD when it's ready.
You may find Bend-Tech helpful when it's time for bending tube.

_________________
If I must be a one-man PC free zone, so be it!


Top
 Profile  
Reply with quote  
PostPosted: October 19, 2020, 1:37 am 
Offline
User avatar

Joined: October 23, 2010, 2:40 am
Posts: 1450
Alex, looking forward to following your build! And seeing lots of pictures!!
:cheers:

_________________
Cheers, Tom

My Car9 build: viewtopic.php?f=35&t=14613
"It's the construction of the car-the sheer lunacy and joy of making diverse parts come together and work as one-that counts."

Ultima Spyder, Northstar 4.0, Porsche G50/52


Top
 Profile  
Reply with quote  
PostPosted: October 19, 2020, 10:30 am 
Offline

Joined: December 29, 2007, 10:41 pm
Posts: 1004
Location: Vancouver, BC
Sounds like an interesting project. Have you thought of a stepdown/up box similar to what Elva/Rytune used with their Formula Juniors? It was a small gearbox with three gears, one small and two large than allowed the driveshaft to pass under the driver, then through the 'box to bring the output back to where the diff flange was.
They were noisy as can be due to the spur gears, but they did work. At one point I had thought about building something but have a drive belt instead of gears, to be used in something similar to your build but time/space/money/life/other projects happened.


Top
 Profile  
Reply with quote  
PostPosted: October 19, 2020, 3:17 pm 
Offline

Joined: October 18, 2020, 4:28 pm
Posts: 17
Thank you for the warm welcome!

I have not considered a step-down box yet because I'm trying to keep the number of components to a minimum.
Also not sure how it would hold up to the 240hp and whatever torque the V8 puts out. I will definitely look into the Elva/Rytune, thanks for the tip!

As you can see, I haven't even started laying out the frame as I'm still deciding on a lot of the components and I'd prefer to start doing that once I have most of the packaging figured out.
The sump will be replaced with a dry-sump so there will be more ground clearance than in this mock-up.

The driveshaft angle is currently at 9 degrees and I was told this shouldn't be an issue as long as the output and input shafts are parallel to each other.
I will either have an aluminum one made or if I feel fancy, I'll go with carbon fiber.

This is still a very rough draft, I'd give it as much weight as a doodle on a paper napkin but until I get all my components in and 3D scanned/drawn up, it's what I'm working with for now.
I'll be getting an empty transmission case next week so I can get that drawn up along with the bell housing.

Can't wait to get this out of my brain and into a physical form!


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
Reply with quote  
PostPosted: October 20, 2020, 7:57 am 
Offline
User avatar

Joined: January 2, 2009, 1:45 pm
Posts: 1318
Location: Halifax, Nova Scotia
It is perhaps more reminiscent of an Indy roadster than a formula car, but have you considered offsetting the engine and driver so the driveshaft is beside you? Not the image you are after I realize.

_________________
Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601


Top
 Profile  
Reply with quote  
PostPosted: October 21, 2020, 8:00 am 
Offline
User avatar

Joined: September 22, 2005, 8:12 am
Posts: 1879
Location: 4AGE in S.E. Michigan
How about a transaxle? It would lower the floor 2 or 3" and you could possibly lower it more by placing the pedals lower and on each side of the driveshaft hump.
davew


Top
 Profile  
Reply with quote  
PostPosted: October 21, 2020, 11:00 am 
Offline
User avatar

Joined: October 24, 2008, 2:13 pm
Posts: 5326
Location: Carlsbad, California, USA
davew wrote:
How about a transaxle? It would lower the floor 2 or 3" and you could possibly lower it more by placing the pedals lower and on each side of the driveshaft hump.
davew


Interesting idea, Dave. Plus, it would get the shifter moved to the right (or left) side too.

Also, do you remember the fellow from Utah who went through a very extensive analysis of moving the driveshaft to the the side of the car similar to an (Italian/British?) Grand Prix racer of the 50's? It might be worth doing a search here for his build log.

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


Top
 Profile  
Reply with quote  
PostPosted: October 21, 2020, 1:40 pm 
Offline
Mid-Engined Maniac

Joined: April 23, 2006, 8:26 pm
Posts: 6410
Location: SoCal
You're right that using a dry sump allows lowering the engine. The problem is that most automotive transmissions have a bellhousing that hangs down just as low as the OEM oil pan, so while the engine pan is no longer be a concern, the assembly as a whole still can't be lowered. Depending how you feel about it, you can saw off the bottom bit of it and gain maybe an inch, but as far as I know, most race cars end up going with a small diameter flywheel and clutch to be able to lower the entire assembly (and to reduce rotational inertia).

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/


Top
 Profile  
Reply with quote  
PostPosted: October 21, 2020, 7:13 pm 
Offline

Joined: October 18, 2020, 4:28 pm
Posts: 17
Thanks for all the great input!

Formula cars did at times use a similar setup (Maserati 250F in one version as an example). I have definitely thought about offsetting the engine like they are in many period race cars along with many Austin Specials. I'm too much of a sucker for symmetry to be able to go that direction, I'm aware the offset would be better for handling. We all pick our compromises and this will just have to be a fault from the get-go that I'll live with. I will be adapting the transmission to shift via cables so I can place the shifter in the exact spot I have yet to determine. This is much easier to do with the side shifting Super T10. It's definitely true that the dry-sumping will mostly benefit ground clearance under the engine. The lowest point in the car will still be the bell housing and the transmission case itself from what I can tell.

As to the seating position: I actually want my feet to be on top of the transmission where I will have a Wilwood or Tilton pedal box. The clutch will also be hydraulic to simplify installation. This is more in line with a modern GP driving position than a traditional one but laying down more should lessen (to a small degree) the effect of me sitting on the driveshaft in terms of CG. The seat you see in the mock-up is just there for reference. I will be creating a custom molded seat cushion that will go straight into the body. Having my feet up there will also allow me to pack the mufflers in there right next to the gearbox, I'm trying to package everything as tightly as possible. I basically want this body to be 26-27" wide. The entire exhaust will be ceramic coated and then I will add insulation in critical areas to not fry myself or crucial components.

I had considered transaxles (Porsche 944 turbo and Alfa GTV6) but ultimately ended up not going that direction as the parts availability is much greater (and cheaper) when going with the American components. At the same price of a nice used Porsche/Alfa transaxle I am getting a rebuilt Super T10 with the gearing I like and an aluminum 8.8" IRS differential with a LSD and the gearing I need.

Good note about the rotational inertia KB58! I'm planning on using a 13lb aluminum flywheel on this engine. Along with the lightweight (either aluminum or carbon) driveshaft it should pass the power through quite nicely.

I'll know more soon as the Engine is being delivered this Friday, the transmission should be here by the end of next week. I'm sourcing a bell housing and transmission along with the headers so I'll be able to tell what I'm working with by the end of next week I hope. Tires are also on the way so I'll be able to lay everything out and get a feel for it.

I'll also be building a seat box to mock up the seating position to see if it feels good or not. If it doesn't, I'll change the setup. Might even go a whole other direction and build a mid-engine car instead if I don't like how it feels.

I'll post pictures as soon as I get more parts in!


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
Reply with quote  
PostPosted: October 21, 2020, 7:25 pm 
Offline

Joined: October 18, 2020, 4:28 pm
Posts: 17
KB58 wrote:
You're right that using a dry sump allows lowering the engine. The problem is that most automotive transmissions have a bellhousing that hangs down just as low as the OEM oil pan, so while the engine pan is no longer be a concern, the assembly as a whole still can't be lowered. Depending how you feel about it, you can saw off the bottom bit of it and gain maybe an inch, but as far as I know, most race cars end up going with a small diameter flywheel and clutch to be able to lower the entire assembly (and to reduce rotational inertia).


Ha, I didn't realize who I was talking to until I posted. I bought your Kimini book! I'm in SoCal as well (


Top
 Profile  
Reply with quote  
PostPosted: October 21, 2020, 7:36 pm 
Offline
Mid-Engined Maniac

Joined: April 23, 2006, 8:26 pm
Posts: 6410
Location: SoCal
Hah, it's just me.

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/


Top
 Profile  
Reply with quote  
PostPosted: October 22, 2020, 12:06 am 
Offline

Joined: August 14, 2006, 1:15 pm
Posts: 57
Location: Burbs of Detroit
KB58 wrote:
You're right that using a dry sump allows lowering the engine. The problem is that most automotive transmissions have a bellhousing that hangs down just as low as the OEM oil pan, so while the engine pan is no longer be a concern, the assembly as a whole still can't be lowered. Depending how you feel about it, you can saw off the bottom bit of it and gain maybe an inch, but as far as I know, most race cars end up going with a small diameter flywheel and clutch to be able to lower the entire assembly (and to reduce rotational inertia).



Use a smaller diameter flywheel and reverse the starter so it is behind the engine rather than beside the engine. You can use a multi-plate clutch to reduce diameter and and retain torque capability

And I have the Kimini and Midlana books too


Top
 Profile  
Reply with quote  
PostPosted: October 22, 2020, 1:54 am 
Offline
User avatar

Joined: October 23, 2010, 2:40 am
Posts: 1450
215monoposto wrote:
I'm too much of a sucker for symmetry to be able to go that direction

Channeling JDKemp: "Symmetry is over rated."

Sorry, couldn't pass up quoting JD. Must be the time of year... :shock:

Looking forward to following your build. Love the 215!

_________________
Cheers, Tom

My Car9 build: viewtopic.php?f=35&t=14613
"It's the construction of the car-the sheer lunacy and joy of making diverse parts come together and work as one-that counts."

Ultima Spyder, Northstar 4.0, Porsche G50/52


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 37 posts ]  Go to page 1, 2, 3  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 11 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

Jump to:  
POWERED_BY