Project MBT-8 914 (warning - big pics for dial-up), new build thread for my V8 tube car Options

[grantsfo]

Dang that is too cool!!! I do have to ask how much will that thing weigh once its finnished? Theres a whole lotta steel there! I think you should see if Porsche wants to take a run at NASCAR!

[turbo914v8]

In your previous picture of the oilcan, standing on end is what appears to be your rear stub axel. Can you provide details regarding that part? What car is it from? Part number? I know that you have the 930 CV's and I am wondering what parts you used to connected the 930 CV's through the stock 914-swing arm with no adaptors.

I thought someone may wonder what that was... actually that isn't off of my car (IMG:style_emoticons/default/blink.gif) They were working on the Thing next to mine and I think one of the guys picked it up off the ground and thought it was mine. I just left it there (IMG:style_emoticons/default/happy11.gif)

As for my setup specifically, I have Turbo Carrera axles and hubs. Talk to Jim at Patrick Motorsports for all the specifics, but he sells some simple spacers that go in the mix to make the longer Carrera stub axles and hubs work with the narrower, stock 914 wheel bearings. Works really slick. The axles can be bought new with the stub axles as an integral part. Then you just need Carrera hubs, his spacers and it all goes together. And the Carrera CVs bolt directly to the 930. He gave me a matching price on the parts (to Pelican's prices which were cheaper when I bought my stuff - don't know about now) when I bought the flanges and spacers from him.

Brett - The toe change shouldn't be too bad over a couple inches of bump - but that is left to be seen. All the links are adjustable, and I have to mess with the caster angle of the rear to tune it out. It shouldn't be anywhere near as bad as the trailing arms were. Also, camber gain is relative between the length of the upper and lower - so it is a short upper, but somewhat short lowers. I calculate 1 degree gain at 2" of bump and 1.5deg at 3" of bump. After that I drag the car on the ground, so gain becomes irrelevant. Remember, any suspension design will work if you stop it from moving (IMG:style_emoticons/default/laugh.gif)

But good eye as it looks to be really short, but the tube diam and rod ends can be deceiving - it is around 8-3/8" long and the bottoms are like 9 - 9-1/2" long IIRC.

Thanks again for the great information. Man your smart. (IMG:style_emoticons/default/beerchug.gif)

[byndbad914]

Thanks again for the great information. Man your smart. (IMG:style_emoticons/default/beerchug.gif)

Heh, thanks for the compliment. Probably more resourceful than smart - when I need to figure out how to make something work, I get the phone and start harassing all the usual suspects in the Porsche world. (IMG:style_emoticons/default/poke.gif)

I think Jim Patrick gets a lot of (IMG:style_emoticons/default/stromberg.gif) on the various forums, but he has been a good guy to talk to (at least for me) in the past few years. He was somewhat of a dick a few years back the first couple of times I tried to call his shop and order stuff and always went elsewhere. But maybe he had a change of heart a couple years ago (IMG:style_emoticons/default/confused24.gif) Maybe he was reading the forums and unlike George at AA, actually took the bad-mouthing seriously and made a change. In any event, he is NOT cheap (typically his prices are higher than other places for the exact same stuff) but anytime he has helped me out I bought the stuff from him as my "consultation fee" so to say.

And when suppliers are cool to me I give 'em props, so I always promote Pelican, Otto's and Patrick for parts and help. That is my main resources. There are others I have not bought from yet that are quite popular, but for now Pelican is 5 blocks from my house, Otto's is about 10 miles and otherwise it is Patrick.

[Brett W]

Brett - The toe change shouldn't be too bad over a couple inches of bump - but that is left to be seen. All the links are adjustable, and I have to mess with the caster angle of the rear to tune it out. It shouldn't be anywhere near as bad as the trailing arms were. Also, camber gain is relative between the length of the upper and lower - so it is a short upper, but somewhat short lowers. I calculate 1 degree gain at 2" of bump and 1.5deg at 3" of bump. After that I drag the car on the ground, so gain becomes irrelevant. Remember, any suspension design will work if you stop it from moving laugh.gif

But good eye as it looks to be really short, but the tube diam and rod ends can be deceiving - it is around 8-3/8" long and the bottoms are like 9 - 9-1/2" long IIRC.

Actually I thought about it some more and you may have a decent design for a hybrid car. If you set it up so that the front links will toe the suspension in on braking and bump you can help stabilize the chassis. This will make the car much easier to drive for a non-professional driver.

You are right the less the suspension moves the more all suspensions become the same. That was something else that I studied with my design. In a race car with very limited suspension travel for instance, struts and dual a-arms have similar characteristics.

What does your roll center do in bump and roll? Where is it in location to the front? How is it in relation to the CG height in the rear?

Car is looking good. You plan on painting or powder coating the chassis when your are done?

[byndbad914]

Actually I thought about it some more and you may have a decent design for a hybrid car. If you set it up so that the front links will toe the suspension in on braking and bump you can help stabilize the chassis. This will make the car much easier to drive for a non-professional driver.

You are right the less the suspension moves the more all suspensions become the same. That was something else that I studied with my design. In a race car with very limited suspension travel for instance, struts and dual a-arms have similar characteristics.

What does your roll center do in bump and roll? Where is it in location to the front? How is it in relation to the CG height in the rear?

Car is looking good. You plan on painting or powder coating the chassis when your are done?

Brett - yous a smart kid and catching on to how I am setting the car up. The car will have toe change (AFAIK all indep suspensions have slight toe change through motion, it is all about minimizing it and choosing if you want over or understeer). I am going for slight toe-in to force understeer, which as you wisely mention, is easier to drive. The key of course is to not have it change from in to out or vice-versa - then the car is a mess to drive.

And you are mucho correct on the "non-professional" part of my driving (IMG:style_emoticons/default/mueba.gif)

Roll center on the front moves down (struts) and same with the rear on bump <both move up on rebound>. I have the RC set higher in the rear (not exactly calculated frankly, but drawn out on paper it is slightly higher and should roughly stay higher all the time at static settings) - again to force understeer. But that value will move around anyway as I set the car to the track (camber changes move the RC - the front will be more affected than the rear tho'). If I have to run a bunch of camber in the rear and none in the front to get tire temps correct, then maybe the rear RC would be lower than the front for instance. I don't expect that scenario of course, but the RC is a moving target; at static settings with same front and rear camber, rear is higher.

As for relevance to cg - I has no ideas unfortunately. This car has never been built, so there is no way of knowing where the weight lies until it is done - then I can weigh it and tip it if I feel so inclined (pun intended) and figure that out.

Why all the understeer tuning? Bcuz it oversteered like a mofo before at any speed. And it is the only car I have ever spun (IMG:style_emoticons/default/wink.gif) And in terms of trying to get all the RCs and ICs right - there will always be compromise and for a 914, it is space. I have 10lbs of (IMG:style_emoticons/default/stromberg.gif) in a 3lb - not even 5lb - bag.

So basically what I get is what I get and I will tune the suspension so it can be all it can be, not all it might have been if you catch my drift. I am not going for the track record with the car anyway, I just wanted to be as safe as possible because I love going really fast v. tons of corners (why I like Willow Springs), and if we could improve some things, then improve them.

BTW, I should check your blog... how is your car coming?

[Brett W]

Unfortunately my car is staring forlornely at me, watching me work on everyone else car or project. Gotta make some bank to play with my own projects. Hopefully I will get to do something on it next month.

I want to get back on the chassis and engine adapter.

[byndbad914]

updated shots of the car after this last weekend. First, the rear suspension is all tacked into place and looking good. I can grab the hub off the jackstand and move it up 4" before any visible toe change (at which point I have ripped the frame off the car to do that in reality with only 3-3.5" ground clearance) and camber gain looks slight. Of course once everything is all done and I am corner-balanced, set at height and running thru the alignment steps will I know exactly what I have. Looks really good tho'

rear close-up roughly near ride-height (jackstands aren't exactly precision for photos (IMG:style_emoticons/default/smile.gif) )


a more overall shot

[byndbad914]

front splitter I have been working on. I will final mount it when it is on the ground and the body panels all lined up and such. You can see the coolant reservoir added as well.


with relief cut for the tires on both sides


And the oil tank mounting

[byndbad914]

and a shot to show the firewall better (new batteries in the camera finally) and the shifter is mounted.



shifter is hard to see, but maybe you get the idea. It is up about 4" from the floor for better accessibility while racing.

[Aaron Cox]

sick man... totally over the top super cool sickness goin on....

[Andyrew]

I agree with aaron!!

Im lovin it!

[drive-ability]

"byndbad914"

You know I love the hole car but especially the scale of the material, I like the big tubes, heim joints / everything is built up to be over kill. It might be heaver than some but I like it that way.... (IMG:style_emoticons/default/beerchug.gif)

[Sammy]

Wow, very impressive car, that is soooo much work. But,..... it aint a 914.
It has 914 doors, a 914 roof, windshield, and dash but that is about it.
You should name it after yourself. It's more your car that a Porsche (IMG:style_emoticons/default/wink.gif)

[turbo914v8]

Great update. This is what a 914 was meant to be. Living up to its full potential. My .02 worth. Love the suspension. (IMG:style_emoticons/default/aktion035.gif)

[byndbad914]

thanks for all the comments guys. Sammy - I like to think of this car as a 914 the same way a NASCAR Nextel Cup car is a "stock" car. I need to get me a new Ford Fusion with the 358 cube V8 option so I can add heads and a cam to and go racin' (IMG:style_emoticons/default/biggrin.gif)

I have a short-track 353cube V8 and apparently I might be in the NASCAR weight classes anyway (IMG:style_emoticons/default/idea.gif) Anybody see the Excellence spoof on the Porsche NASCAR? I may have beat them to the punchline! (IMG:style_emoticons/default/w00t.gif)

[Brad Roberts]

That is the best use of a 914 control arm I have ever seen..LOL

Cant wait to see you drive it.


B

[byndbad914]

not much happened last week unfortunately (IMG:style_emoticons/default/sad.gif) But, I had some requests for clearer front suspension shots, so here are a couple.

The plated arm (running fore in the A) is from Kanna Motorsports, as well as the "ball joint" machined replacement to work with the spherical joints. From their 935 front suspension stuff - they were cool about selling piece parts since I don't have a 911 setup I am trying to bolt into.



and a shot of the upper mounting. This will be changing a fair amount as they didn't leave room for the fuel cell (IMG:style_emoticons/default/smoke.gif) Gotta have that... so the mount will be lowering 1" meaning I have to take the struts to Bilstein and they "quoted" (over the phone - hopefully it won't change when the time comes) $125-150 each to cut them down a couple inches so I can get some travel back out of them. The camber plates were custom-made by Kanna also to match the 18mm strut diameter. They used a 3/4" spherical bearing and machined a spacer to 18mm that slips into it (thin but works).


Sorry, not detailed shots of the machined ball joint replacement or shim at the top. Gonna have to wait on that until I tear it apart again (IMG:style_emoticons/default/wink.gif)

[byndbad914]

slow moving the past 2 weeks as AJ had a race in Vegas that kept him busy on his own truck. Now he is back on the car and welding has began. The center is mostly done and the rear is done. He is going to button up the front next week. Most of the welds are absolutely amazing. A couple you can tell were near the end of the day when fatigue was setting in (IMG:style_emoticons/default/happy11.gif)



cloudy closeup but you can more or less tell how even the beads are on this car



And the firewall area



some more to come next...

[byndbad914]

rear area closeup



front still needs welding and the strut mounts lowered/modified to fit the fuel cell, but here is an iso from the front

[byndbad914]

and all the stuff I get to put back on when the welding is all done and the suspension is bolted into place. Hopefully by end of next week I can start that process!