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The JF2005a ( My car)
want2race - 20/6/05 at 02:31 PM















But Unfortunately I have run out of money/hope/desire and all the things that matter

zetec - 20/6/05 at 02:52 PM

That sure looks like a heavy duty chassis, with light duty wishbones...What engine are you fitting?

ned - 20/6/05 at 03:37 PM

an interesting use of extra tubes and gussets, is the engine going to be running big power?

Is the chassis finished yet?

Ned.

[Edited on 20/6/05 by ned]

want2race - 20/6/05 at 03:45 PM

quote:
Originally posted by zetec
That sure looks like a heavy duty chassis, with light duty wishbones...What engine are you fitting?


light duty ? nope!
Light ? Yes

They are made from Chromoly with a 4mm wall thickness! Its insainly strong and light

want2race - 20/6/05 at 03:47 PM

quote:
Originally posted by ned
an interesting use of extra tubes and gussets, is the engine going to be running big power?

Is the chassis finished yet?

Ned.

[Edited on 20/6/05 by ned]


The engine should make around 400bhp at full glory.

I am fitting a turbocharged Mx-5 engine.

Is it finished? Almost. I still need to mount the steering rack and then I will be. First I have to find out what bolts it uses.

As for weight, its all made from 18ga steel which is lighter than normal. I just took it off the scale moments ago and without the floor (13lbs of ali) it was 54lbs as it stands.. LIGHT!

ned - 20/6/05 at 04:09 PM

I'd be tempted to triangulate the floor, tranny tunnel and above foot well areas a bit myself, but looking good, the chassis is the slow bit, once it's painted it does come on quicker and start to look more like a car, trust me, been there

jambojeef - 20/6/05 at 04:58 PM

It looks very different to mine!

I might be missing the point of the design on your chassis but it looks like you've got very stiff top tranny tunnel end and stiff engine bay floor but not much to stop the top rails of the engine bay flexing - IMHO!

Diagonal frm tranny top to front end of engine bay? Might help with rigidity...? Maybe some more diagonals between top and botom tubes int he engine bay too? Thats what Ive done after reading posts in this section!

Geoff

JoelP - 20/6/05 at 06:18 PM

are you using pull rod suspension? cant see any shocker points, or are they rear bones?

want2race - 20/6/05 at 09:10 PM

quote:
Originally posted by jambojeef
It looks very different to mine!

I might be missing the point of the design on your chassis but it looks like you've got very stiff top tranny tunnel end and stiff engine bay floor but not much to stop the top rails of the engine bay flexing - IMHO!

Diagonal frm tranny top to front end of engine bay? Might help with rigidity...? Maybe some more diagonals between top and botom tubes int he engine bay too? Thats what Ive done after reading posts in this section!



Geoff


I'll start with one more pic


that shows the area my rollcage will attack to in front. Its VERY strong and makes a massive difference to tortional strength.


Its also tied into the motor mount.

As for the top of the engine bar flexing.. Nope.. The engine will be a stressed member and once its installed and bolted it will make the entire front section one giant rigid mass.. No rubber mounts here!

want2race - 20/6/05 at 09:11 PM

quote:
Originally posted by ned
I'd be tempted to triangulate the floor, tranny tunnel and above foot well areas a bit myself, but looking good, the chassis is the slow bit, once it's painted it does come on quicker and start to look more like a car, trust me, been there


I hope so! Its a pain in the butt!

I want to triangulate under the seat but first i have to buy one to see where I can and where I cannot..

want2race - 20/6/05 at 09:12 PM

quote:
Originally posted by JoelP
are you using pull rod suspension? cant see any shocker points, or are they rear bones?


I want to. Right now i still intend to but I want to mount the steering rack first and get perfect steering geometry.. After that I will determine how to cantilever the fronts.

MikeRJ - 20/6/05 at 09:17 PM

quote:
Originally posted by want2race
[As for the top of the engine bar flexing.. Nope.. The engine will be a stressed member and once its installed and bolted it will make the entire front section one giant rigid mass.. No rubber mounts here!


Are you not worried about vibration? It could make it pretty unpleasant to drive I'd have thought?

ned - 20/6/05 at 09:41 PM

i still think the engine bay top braces or an alternaitve top frame to tie the sides to the bulkhead is worth considering even with a solid mounted engine.

this is how i did my floor for you info:

seat mounts
seat mounts

want2race - 21/6/05 at 12:09 AM

quote:
Originally posted by MikeRJ
quote:
Originally posted by want2race
[As for the top of the engine bar flexing.. Nope.. The engine will be a stressed member and once its installed and bolted it will make the entire front section one giant rigid mass.. No rubber mounts here!


Are you not worried about vibration? It could make it pretty unpleasant to drive I'd have thought?


I am going to use Delrim ( its scateboard wheels) and it should remove most of the vibrations that are suttle and only transfer harsh vibrations.. Worst case I will make the seat acsorb most of it

want2race - 21/6/05 at 12:10 AM

quote:
Originally posted by ned
i still think the engine bay top braces or an alternaitve top frame to tie the sides to the bulkhead is worth considering even with a solid mounted engine.

this is how i did my floor for you info:

seat mounts
seat mounts


nice floor flanders!

I really like what you did with that. I may have to steal that design.

Why is your metal so rusty ?

AS far as the engine bay i want to try keep it open so I dont have issues getting to anything. I already think its going to be a problem.. I suppose we will see when its all done..

[Edited on 21/6/05 by want2race]

Rorty - 21/6/05 at 03:24 AM

quote:
Originally posted by want2race
quote:
Originally posted by zetec
That sure looks like a heavy duty chassis, with light duty wishbones...What engine are you fitting?
They are made from Chromoly with a 4mm wall thickness! Its insainly strong and light

How can you call 4mm wall wishbones light?
With 4130 tube 0.9mm would be too light, 1.2mm would be light and 1.6mm would be about right.
BTW the Delrin you intend using for isolation mounts will transmit almost the same frequencies as steel. It's a very rigid material. You'd be better off using a medium shore (say, 65) polyurethane.

flak monkey - 21/6/05 at 07:57 AM

quote:
Originally posted by want2race
quote:
Originally posted by zetec
That sure looks like a heavy duty chassis, with light duty wishbones...What engine are you fitting?


light duty ? nope!
Light ? Yes

They are made from Chromoly with a 4mm wall thickness! Its insainly strong and light


My full set of wishbones weighed 5kg. Now thats light. I'm betting that yours weighed a considerable bit more than that.

Chromoly steel is actually heavier than plain carbon steel. Cr and Mo are both very heavy/dense elements.

Chromoly steel is no stiffer than normal mild steel, it is stronger though. But I would have said that with some careful design you could have made those wishbones from a lot thinner steel, and made them considerably lighter as well.

Also bear in mind no matter how you look at it, tubes loaded in bending are always better to be larger diameter thin wall section, than small diameter heavy wall section. (Second moment of area stuff)

David

ned - 21/6/05 at 09:17 AM

quote:
Originally posted by want2race

I really like what you did with that. I may have to steal that design.

Why is your metal so rusty ?

AS far as the engine bay i want to try keep it open so I dont have issues getting to anything. I already think its going to be a problem.. I suppose we will see when its all done..

[Edited on 21/6/05 by want2race]


chassis had some surface rust, has since been blasted and powder caoted.
moe up-to-date pic here

checkout liam's photo archive, he has a really nice chassis with a lot of extra triangulation and a removable over engine frame/brace.

Ned.

jambojeef - 24/6/05 at 09:39 PM

Want to Race...

You do indeed need to check out Liams photo archive for the photos of his chassis - if just to look at a great chassis.

Having been buddies with the guy for many a year I can tell you he has become slowly obsessed with chassis rigidity!

Thing is - when you actually look at what he's done its just clever movement of virtually the same amount of metal as the locost chassis but through building balsa models and CADing the chassis all the time!

Liams removable engine bay brace is a great idea which I have borrowed from for my BEC cradle / engine bay brace.

Maybe U2U him and ask if you can build one under license!

Geoff

Bob C - 24/6/05 at 09:54 PM

A rigid mounted 4 pot is going to leave a tingling sensation on the whole body!!! Not a long distance cruising machine I don't think! Was this because of the PPF mounting at the gearbox end?
400 horses is 33% higher than any mx5 I've seen in this country (the maddest guys were pushing 270/280 at the crank) And those guys had spent thousands on FM2 turbo gear, link or motec ECU, big intercoolers, water injection etc. etc - whats the recipe for 400? which basic engine are you starting with? I presume it would have to be bored/stroked to get up there??
cheers
Bob

kb58 - 25/6/05 at 05:30 AM

quote:
Originally posted by want2raceAs for the top of the engine bar flexing.. Nope.. The engine will be a stressed member and once its installed and bolted it will make the entire front section one giant rigid mass.. No rubber mounts here!


Unless the engine was designed for this, it may not be a good idea.

When you say the chassis is "really stiff," do you have any numbers?

want2race - 25/6/05 at 01:38 PM

quote:
Originally posted by Bob C
A rigid mounted 4 pot is going to leave a tingling sensation on the whole body!!! Not a long distance cruising machine I don't think! Was this because of the PPF mounting at the gearbox end?
400 horses is 33% higher than any mx5 I've seen in this country (the maddest guys were pushing 270/280 at the crank) And those guys had spent thousands on FM2 turbo gear, link or motec ECU, big intercoolers, water injection etc. etc - whats the recipe for 400? which basic engine are you starting with? I presume it would have to be bored/stroked to get up there??
cheers
Bob


Its going to be a racing car only.. No real street use and probably not road legal.

Whats it take ??

Well the answer lies in a sister company block from KIA that can be bored to 2.49liters and that coupled wiith a 1.8 miata head can generate 13.9:1 compression statically and around 12.9:1 dynamically with a rather radical cam.

Everything will be ballanced and blue printed and high speed honed.

As for the comment on the strength of the engine to be a stressed member. I will probably have enough strength in the block but if it isnt, its $149 for another block and $400 in machining so its not the most costly experiment if it cracks..

And about the LIAM comments. I would like to put an over engine brace but I wont know how high it goes until i get my body panels. At that point I will probably add something like Liams car.

want2race - 25/6/05 at 01:39 PM

quote:
Originally posted by kb58
quote:
Originally posted by want2raceAs for the top of the engine bar flexing.. Nope.. The engine will be a stressed member and once its installed and bolted it will make the entire front section one giant rigid mass.. No rubber mounts here!


Unless the engine was designed for this, it may not be a good idea.

When you say the chassis is "really stiff," do you have any numbers?


I dont have any machines to test regidity.. And honestly I could not justify paying someone with one to do it either.

Any other ways to do it ?