new build a Porsche LMP

[John]

hi guys , i have made a couple of posts already and was wondering where i should realy be so to speak , and as i'm also building a Porsche i hope you dont mind if i join you here.
the car i'm scratch building will be a copy of the Porsche 1995-96 WSC LMP car run by Joest racing

the chassis is 95% complete, just the rear shocks to mount etc and alloy paneling, then its ready for auxillieries to be fitted

power will be a turboed 3ltr 6cyl Subaru engine and transaxle, i have thought of fitting a bent 8, but the cost of a trans axle etc would be just a little out of reach at this time , but is certainly an option in the future.
my aim is to get it to a rolling chassis , fit the engine etc and then start the hard part and build a body.
the person who designed and built most of it so far has not only all chassis and related parts on a CAD disc, he has also done all the body profiles to be CNC cut to make a plug, and to test his drawings he has had a full set of panels laser cut out of 1mm zinc plate in 1/4 scale and assembled a model and it fits together perfectly,

and underneath it all is a scale model of the chassis.
so with a fair bit of luck and hopefully some help and advice from you guys, i might get a half decent body built one day.
i have started a photobucket site of build progress , link here
stryka_01/Stanton WRC-95 - Photobucket - Video and Image Hosting
so feel free to drop in and check up on me , and let me no if i'm heading up the wrong track.
cheers John

[sp250]

i may just have to drop in to see this a little later. steve

[Russ Noble]

Yeah,

Me too! I've got to visit my daughter in Palmy sometime soon!

Cool project John. That should be one real quick car.

Good luck with it. Shall be watching your build with interest.

[Cliff Beer]

Neat project John! Very nice.

Any idea what the undertray looks like? Does your chassis design/config copy the undertray as well?

Thanks for sharing your interesting project - I know many folks will keep a keen eye on your progress!

[Fred W B]

Hi John/kaspa

Nice to see some details of your project here.

A question - Where/what car did those front uprights come from?

Cheers

Fred W B

[Tom]

I am curious about those front uprights - it looks like there is a big spacer under the lower ball joint interface. Would that not cause a considerable bending moment under lateral load?

Second question regards the chassis - it seems like you could put a little more structure to the outside of the car? That would serve to offer more side impact protection (unless the body is designed for that) while also helping to stiffen the car in torsion and side bending. It looks stiff as a brick in beaming.

Tom

[John]

thanks for the support guys, to answer a couple of questions.
yes the drawings cover both front and rear under tray.
the front uprights are mazda Mk 4 RX7, as are discs and calipers
rear is custom uprites with Turbo skyline hubs and rotors , with willwood 4 pot calipers.
your welcome to pop around and have a look any time , i'm only 500 yards from the Manfeild race track, easy to find
just pm me if your goin to be in the neighbour hood
cheers John

[Russ Noble]

Thanks John, Will do.

Tom, valid points. Will there be a bending moment? Yes. Is it significant? Probably not, bearing in mind the weight at the front of the car. Remembering also with the standard setup there is a bending moment too. With the lighter front the moment is probably similar.

Could a little more structure be put to the outside of the car? Yes. Would the gains offset the losses? Probably not. John has not said what the purpose of the car is, but I bet its being built to run in our New Zealand Sportsrace Car Series in the Supersports class. The number one enemy in any race car is weight. I think the compromises made are just right. I'm sure it will be a very quick, good handling car.

[John]

Thanks Russ, yes its being built for the sports car class, i was racing a Fraser Seven, 280hp 500kg with a 6 speed quaife sequential box,with electronic flat shift,
build log here, Monty155 - Photobucket - Video and Image Hosting
and although it was one very quick car, it just couldnt get around the corners as good as a Saker or The Juno, so if you cant beat em join em.
Mr Turnbull [from Sakers] has been and had a good nosey and Bruce also agrees that the side intrusion will be sufficent as is, he also pointed out a couple of very,very clever design features in the way the chassis is triangulated, that gives it incredible torsional ridgidity, which i didnt see, and for the record he gave it both thumbs up.

as for the bottom uprite mount spacers , they are cnc machined out of 4140 and are 30mm dia, a heluva lot stronger than OEM set up.

some of you might also think the front of the chassis from the pedal bulkhead fowared is lacking in triangulation, i no i did, but Bruce pointed out that what Andrew has done very cleverly, is make it a crumple Zone, so on a big frontal that section will collapse before the cockpit starts to move.

As Russ pointed out, with all race cars theres always a compromise between safety and weight, and i feel quite comfortable with how its been designed and built so far, and in Bruces words, it should be as Stiff as a school boy on his first date, what ever that means, i cant remember.

there is still a x brace to go across the top of rear engine bay [ removable] and posibly a diagonal also across the top,[ also removable] i'm just waiting for the final drawing from Andrew with the rear shock, bell crank position ,mounts etc, which will tell me where everything will go,

i managed to get a little done this last weekend , front bulkhead is all cut out ready to be fitted , and i managed to sort out mounting the rear calipers to the uprites.
so although progress is a bit slow, none the less it is progressing.
thanks for the encouragement guys appreciate it.
cheers John

[John]

This is a really cool project. I'm really interested to hear how your engine setup is going to work out. I take it your going to use the EZ30R Subi motor? Jeff Perrin of Perrin Performance has one of those up to 800WHP in his STI, though i wouldn't call the torque curve drivable for a track car. To me, this looks like a way cheaper alternative to a Porsche engine. What are your plans for your engine? And what trans are you going to use?

John

[John]

hi john yes the EZ30 will be the power plant , and have looked at various trans options , was cosidering the 6 speed but on Mr Turnbulls advice i will use a box he has , its a 2wd box with a close gear set and a slippery diff, should do the trick ok.
i have been reading what they have been up to at Perrins, but as you stated, i want a race engine not a drag engine,so we will be quite conservitive with what we do, but what i have planned should make it reasonably quick.
cheers John

[John]

Guys it might pay to keep alook out for sister build, which may pop up in the not to distant future.
I have sent a copy of all relevant data to another Jon,also a forum member, from California, as he is seriously considering building a sister car over there, so it will be good to compare notes and ideas etc.
also a quick question, how do you post thumb nail pics on here , my pics were way to big i no, but i couldnt figure out how you just get the small ones.
cheers John

[John]

God, we have to do something about all these John's on this forum...

But seriously, with those rods and pistons perrin is using, im sure the engine would be good for a frightening amount of power, especially in a lightweight car... Getting the engine sleeved like perrin did is too much trouble and i dont think necessary.

the thumbnails happen automatically. I believe the system resizes them down for you.

[Chris_K]

John,

If you scroll down under the window you write a post in, there is a "Manage Attachments" button. Click on that and you'll get a window to open and you can attach up to 5 pics at a time.

Last I tried, pics have to be less than 800x600 or under certain sizes (as shown on the "Manage Attachments" window). I haven't had it happen automatically for me though.

I've heard there are numerous freeware photo reducers out there. My camera came with software which does this so I haven't looked into it.

The thumbnails do appear automatically.

[John]

ah ha thanks guys ill give it a try
well ill be b#ggered it works .
a couple of pics of rear uprite and wishbone set up and front adjustable sway bar, i have mounted the calipers on the rear uprites but dont have a camera at present[ away getting repaired].will post updated pic when it returns.

Russ, i spoke to Mr J.A this evening and yes he dose still have the mould you mentioned, he will measure it tommorow.
BTW he said the 747 is fueled and ready for take off.
cheers John

[John]

How did you come up with your suspension geometry? And i guess the trans is just a Subi trans? Not a Porsche box or anything?

[Dave Peterman]

Looks good John I'll be watching your progress!!!!

[John]

Thanks Dave, i will try to keep all informed of progress as it happens.

John first and formost i didnt design it , good god i'm not that clever, but the whole thing was designed on CAD, including the suspension.and i have every thing for the car on a Disc.
i have printed out a copy of the chassis file and run a pencile and ruler to connect all the dots so to speak, and find roll centers, cog etc, and all i can say is if it dosnt go around crns quickly ill be very suprised. it has a little anti dive built into the front, the roll centers are spot on for my money and the balance, is very close to 55 r-45 f, as far as i can work out, with the COG directly under drivers bum.

trans will be a modified suby 2wd trans with a CR gear set and slippery diff, should handle the power ill be useing ok.
cheers John

[John]

well its taken awhile but i have finaly worked out how to undress the main chassis file, so now its down to bare bones so to speak i have posted some pics to get an opinion from the technicaly minded.
just be awhere there is still one x brace and probaly a diagonal to go into top of engine bay.
appriciate honest opinions
roll centres ive worked out as accuratly as i can, with bad eye sight and an old slide rule at 40mm front and 50mm rear, center of balance with engine installed, wheels on , no fuel in tanks etc just as it sits with me in the seat, is directly under my bum or approx 300mm in front of roll bar bulk head.
Cheers John