NOHOME
Dork
10/24/13 3:45 p.m.
In reply to NOHOME:
I have a factory manual for an NA Miata and the body dimension sheet shows the subframe mounting points as flat.
NOHOME
Dork
10/24/13 4:15 p.m.
DeadSkunk wrote:
In reply to NOHOME:
I have a factory manual for an NA Miata and the body dimension sheet shows the subframe mounting points as flat.
Yeah, that is what I see from the manual also. However, I have had a hint that there might be more to it than that.
Look at the tube in this rendering. The tube has a slant from front to rearas observed from its location relative to the wheel spokes.
But if you look at the frame welded to the table, it is flat from front to rear.
So something has to give.
All that table picture tells you is that the long tubes aren't bent in the Z axis. They could be stood on end after that welding is done, you can't tell that.
Warren's the guy you want to talk to. Fire him a PM.
NOHOME
Dork
10/24/13 8:56 p.m.
Keith Tanner wrote:
All that table picture tells you is that the long tubes aren't bent in the Z axis. They could be stood on end after that welding is done, you can't tell that.
Warren's the guy you want to talk to. Fire him a PM.
If you mean the tubes in the foreground, I am pretty sure they don't move since the front suspension mount is holding it to the table and he mentions that it does not move after welding.
I can't begin to tell you how impressed I am with the way Warren and his team went through that design and brought it in line with cutting (pun) edge technology to make the low volume production cost effective; that is a hard trick to pull off.
Warren has already indicated that the mountingdetails of the sub-frames falls under the heading of" IP", so I have to respect that. But no one says I can't snoop around till I figure it out!
I gotta tell ya, after 40 years of restoring Brit cars from piles of rust, this is FUN!
tuna55
PowerDork
10/24/13 9:01 p.m.
NOHOME wrote:
I have been looking at the Exocet and can't help but want to cut the front clip off of that and graft it on to the front of the Volvo's firewall. Do you want to sell me some tubes Warren?
You could just buy and assemble an Exocet and cut the necessary parts of the shell away for the 1800 to fit on top.
Seriously.
NOHOME
Dork
10/24/13 9:24 p.m.
tuna55 wrote:
NOHOME wrote:
I have been looking at the Exocet and can't help but want to cut the front clip off of that and graft it on to the front of the Volvo's firewall. Do you want to sell me some tubes Warren?
You could just buy and assemble an Exocet and cut the necessary parts of the shell away for the 1800 to fit on top.
Seriously.
If it were a track rat..yeah I would be all over this. But the project requirements call for a civilized long legged car that cruises down the 401 at 130 kmh while turning around than 2000 rpm, with the AC and cruise control on, but still able to pick up her skirts and scoot.
tuna55
PowerDork
10/25/13 5:54 a.m.
In reply to NOHOME:
You might be able to retain the creature comforts with a bit of additional panel work and insulation to the Exocet base. I am not sure, honestly. If you could refit the dashboard from the 1800 you could even figure out how to hide heat and AC in there.
Ian F
UltimaDork
10/25/13 7:06 a.m.
In reply to tuna55:
That's the main reason why I'd want to use the Miata firewall and dash - it would make fitting the HVAC components exponentially easier. You'd lose the classic car dash, but having spent quite a number of hours behind the wheel of an 1800ES, I don't find the E/ES dash to be all that wonderful. Th earlier cars, maybe; that dash has a more classic look, but the later dash just feels dated. I plan to keep it in my car, but I'll recover it with real wood and install modern gauges.
I was contacted by the previous-previous owner of this car and he gave me some additional history. Apparently it's not quite as nice as it appears in pictures. So cut away.
Ian F
UltimaDork
10/25/13 9:52 a.m.
In reply to NOHOME:
Well... not so much approval as hope that if/when you cut out the frame rails and floor pan, I can figure out a way to get them from you for Crusty (my ES).
In reply to NOHOME:
Were you wanting to know if the mounting locations were parallel to the road, OR are the front and rear subframe pads the same distance from the road? My answer was for the former, not the latter.
I just went to the garage and checked the manual again. The dimensions are all from a datum(possibly the road surface) to the ends of the mounting studs that are welded into the unibody/chassis. The front ones show as 290mm. For the rear subframe the front two studs are 309 mm from the datum and the rear two are 319mm. So, the rear subframe is tipped relative to the road and is mounted higher than the front subframe.
NOHOME
Dork
10/25/13 3:35 p.m.
DeadSkunk wrote:
In reply to NOHOME:
Were you wanting to know if the mounting locations were parallel to the road, OR are the front and rear subframe pads the same distance from the road? My answer was for the former, not the latter.
The top mounting surfaces is what I need to know about. If they mount parallel to a ground plane (my chassis plate) then I can fabricate off of that datum.
Warren's rendering shows the mid-plane tube as slanted forward. I realize that the mounting surface of the rear sub-frame is higher than the front. However, if the tube is slanted, then either the subframes need to be tilted at the same angle of attack, or wedges need to be designed in or ???
I really want those mounting surfaces to be planar to the ground so as to make my life easy(er)
Just read your last reply posted as I was typing. 10 mm is a lot of tilt!
In reply to NOHOME:
The diagram doesn't give dimensions to the mounting surface , only to the end of the studs if I'm reading it right. This seems odd to me, but that's what it looks like.
The rear subframe has to be tilted 10mm if the four chassis studs are the same length.Do you still have the donor tub to measure the length of the studs ?
NOHOME
Dork
10/25/13 3:56 p.m.
DeadSkunk wrote:
In reply to NOHOME:
The diagram doesn't give dimensions to the mounting surface , only to the end of the studs if I'm reading it right. This seems odd to me, but that's what it looks like.
The rear subframe has to be tilted 10mm if the four chassis studs are the same length.Do you still have the donor tub to measure the length of the studs ?
No I don't have the chassis, just bought the suspension assemblies. That would have been too easy.
Might have to go buy a Miata.
tuna55
PowerDork
10/25/13 3:57 p.m.
NOHOME wrote:
DeadSkunk wrote:
In reply to NOHOME:
The diagram doesn't give dimensions to the mounting surface , only to the end of the studs if I'm reading it right. This seems odd to me, but that's what it looks like.
The rear subframe has to be tilted 10mm if the four chassis studs are the same length.Do you still have the donor tub to measure the length of the studs ?
No I don't have the chassis, just bought the suspension assemblies. That would have been too easy.
Might have to go buy a Miata.
Find one in a parking lot and grab a measuring tape. I've actually done this while looking for brake components, on many different cars.
NOHOME
Dork
10/25/13 5:02 p.m.
I did noodle around on the Locost forum. They seem to use the rear structure in its entirety and pretty muck leave it level. If I cant find the angle, I might have to follow their lead and make sure that it can be shimmed at a later date.
I guess the question is whether the effects of mounting the structures level with the ground will make for a suspension that is worse than what was used in 1973 when the car was built. This thing had a positive camber gain for one.
Maybe I need to fly to Atlanta and pour Beer into an engineer until he fesses up!
Course, engineers being designed as they are, it might be cheaper to just buy an Exocet and measure!
Mount the front subframe level and the rear tipped 10 mm. It shouldn't be hard to figure in the 10mm tip between the front and rear mounting holes.
Ian F
UltimaDork
10/27/13 11:39 a.m.
Check this out: http://www.youtube.com/watch?v=zXVS-h_Cm4E&feature=share
NOHOME
Dork
10/27/13 5:02 p.m.
Ian...I have to agree that the video shows the level of commitment this is going to take.
I think that anything less than a re-engineering job of the whole car is going to end up with a crude result: This thing does not like engine swaps! Don't think I could describe a worse situation than the existing one for grafting a Miata suspension on to the front.
Made it back with the parts car today and it is tucked in to a nice dry barn until I need all the bits.
Pete
Ian F
UltimaDork
10/27/13 5:57 p.m.
NOHOME wrote:
This thing does not like engine swaps!
I've been saying that for years and nobody ever seems to believe me.
I'll see if I can dig up any more info about the car in the video. Definitely looks well done so far, but they are essentially custom-building the car from scratch. Staggering amount of work.
Another video of it running: http://www.youtube.com/watch?v=K71d7cDX4ZI
The dash they used... Holden/Vauxhall (GTO here)?
Ian F
UltimaDork
10/28/13 7:45 a.m.
Oh... and another thing I was pondering this morning while thinking about that car. I'd have to watch the video again, but be weary of the floor in the 1800 when designing the chassis. You may notice the mounts for the seats are pretty low. This is because the headroom in the car isn't the greatest. My ex-g/f is 5'-10" (with long legs) and I still had to slam the seat as low as it can go so she wasn't hitting her head. With that in mind, a frame needs to be a perimeter type with room to recess the seats between the rails.
It's funny... years ago there was a thread on an Alfa board by a guy who was in the process of hot-rodding a Spider with a SBF and a Cobra-like tube chassis. He posted tons of pictures and was moving along very quickly. Then all of sudden, the project just stopped. I haven't looked at the thread in years, but the last time I did there hadn't been progress in a couple of years. Part of me wonders if it's because he went ballz-out building his chassis and then when he had a roller and started putting the floors in, he realized neglected to consider the floor-seat-driver position. His floor was about at the level of the lower door opening flange, which like an 1800, isn't going to work in a Spider where the floor is normally a good 4" lower than that flange. Just loooking at the pictures, you could tell his head was going to be over the top of the windshield. Oops.
Like I've said: I've thought a LOT about how to do this.
NOHOME
Dork
10/28/13 8:33 a.m.
Ian:...
Glad you have put a lot of thought into this, it certainly requires it if the result is going to be more than a compromised result. You and I are in full agreement that this is not a car that left a lot of room in the design envelope for modifications; what is there was built to work with everything else that is there. It is a good design, just not meant to be messed with.
Already ahead of you on the seat pans. Cobra kit cars have this flaw, and I have not sat in a Cobra that did not feel like I was sitting ON a Cobra.
Engine swaps, done poorly, are like giving Granny a boob-job.
NOHOME
Dork
10/29/13 9:45 a.m.
I tell you, unless you are me, listen to Ian when it comes to engine swaps in the P1800! This thing is evil.
I seem to be going down Keith's road in abandoning the Miata K member and just making new frame rails. Here is where the new frame is going to land; inboard of the existing frame-rail by about 3/4". One (potential) plan is to run the new frame back to the lateral crossmember. Unless I can convince myself that there is some advantage to it, I will remove the original frame structures entirely up to the rad support. If I can do so without destroying them, they might be useful to someone restoring one of these.