The goes-way-too-f#$king-fast-mobile

If you have a project that you are working on, and want to show off some work that you have done to it, post it in here!
Post Reply
User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:
The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Sat Jul 24, 2010 2:08 am

A friend and I started this ~ 2 years ago and never quite made it out of the planing stage.

The idea is a mid engine rwd street legal tube frame car weighing under 1500lb with a single driver, that has a very low center of gravity positioned for optimum drift fun.

So far a Mazda 13B from an RX7 and an eclipse FWD 5 speed is the proposed powerplant/tranny combo, chosen for power to weight ratio and cheapness respectivly.

I forget the wheelbase and length(and am too lazy to measure the cad model right now), but as you can see it's going to be small and compact, sub miata sized, but bigger than a gocart by a few inches. Iirc width is at 50" right now or thereabouts.

Plans are to keep the total price under 3K for the frame, engine, tranny, seats, etc needed to get it driveable until we get the bug to do more to it.

The roll cage isn't complete in cad yet, but it will be fully caged in.

Body will either be stretched black tonaue cover material, aluminum sheet, or fiberglass.

Image

That's the current model, which has some issues that need to be addressed, mainly engine/tranny mounting and where the wheels/hubs/etc go.

Plan is to use mitsubishi hubs for the rear so that custom axle shafts aren't needed, and whatever is small and easily aligned up front.
Axle shafts will be 2 of the shorter (I want to hazard passanger side) shafts, since the plans are for the diff being in the absolute middle to eliminate torque steer as much as possible.

Fun part will be doing suspension. The ideas we were kicking around were to use a modified 4wheeler suspension design or a modified motorcycle suspension, but after looking at the wide availability of air bag suspension products out there, that might be a better idea.

The other idea is to nab the adjustable suspension setup out of a high-end luxery vehicle/sports car and use that, but space constraints might kill that.

Another option would be torsion bar, but that might cause rigidity issues in the frame and could penalize adjustability.

The suspension layout of the Rover P6 would be quite nice, since there wouldn't be as much vertical height. Couple that with some small bags instead of springs/struts, and it might just work.

Image

Steering rack would likely be out of a miata, since that's the smallest width rack I can think of.

It's going to be 4 wheel disc brake with a steering assist mode, that will allow for independent control of which side gets brake force (some cars already do it with trac control) An abs solenoid block will be wired in for that.

It looks like hydroboost will be the way to go for brake booster, since there's no way a conventional vac booster would ever fit. Would a brake booster even be needed?

Radiator will likely be mounted in the front with an aux fill in the back, MR2 style. That's what the large section on the front nose is for. If that isn't feasable, it will be flat mounted above the engine compartment with some huge fans.

Gas tank will either be up front, or in the passanger side rear of the engine compartment. Up front would be better for safety and weight distribution I'd think, but I could be wrong.

Headlights will be flip-ups, directinals/tails will be frame mounted along the rear and front roll cage bars, with a high mount tail at the top of the cage.

Seats will be racing 5 point, sparco or similar. Dash will be a hybrid digital/analog using a small lcd display and a section of 2 way mirror to superimpose the information.

The Megasquirt 3 is going to be used as the ecu, with some firmware tweaks to allow for some fun features like automatic exhaust cutout actuation (with override switch on the dash), the "batt outa hell" button (richen up mixture, remove rev limit, open cutout, increase boost pressure, pump full oil via the metering pump to the rotor housings).

The speedo signal and 4 wheel speed sensors will be used in conjunction with a 6 axis inertial measurement unit to log the fun and tune the suspension on the fly if bags or variable suspension is used.

It's something that's eating me up, I know it can be done, I just don't have time or parts...

Feel free to ask away, give sugjestion, and criticisims. I thrive off bouncing ideas off of people.
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Sat Jul 24, 2010 10:24 pm

Another idea was to have a limited amount of rear wheel stearing to reduce the turn radius a bit, but that's more of a pipe dream I think.
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

mitsubitchin
Posts:8
Joined:Sat Jun 19, 2010 2:12 pm
Location:West Palm Beach florida

Re: The goes-way-too-f#$king-fast-mobile

Post by mitsubitchin » Sun Jul 25, 2010 10:45 am

Don't go crazy dreamin, cuz you will never finish.Lol. Get in there and do it. Build it right the first time. I think its a bad ass idea. Do it... Make 4sho that cage is 100%. Don't forget to make wheelie bars. Cuz ya kno ya gona wana drag race it!!!!!
minitrkin since 1988....
1990 mitsubishi mighty max 4g64 mpfi std cab short bed
1990 isuzu pickup 4zd1 carby std cab short bed
2005 atless ll8 i-6 chevy trailblazer (ext)

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Fri Aug 06, 2010 3:13 am

Well, I'm most likely going to scrap the current frame design (sooo glad it's just a cad model!).

Found out that I'll be wider than a miata, there's no easy way to make the suspension, and all my engine and tranny weights and dimensions for COG(center of gravity) calculations are off by quite a bit. I also went about the layout of the model a bit bassackwards, in that to change the frame dims I need to dig all the way back to one sketch, change it, and then it breaks constraints...

Not to mention that after actually taking the time to look at a 13B more closly, I realized that the intake and exhaust are on the left side of the block when looking at the crank pully, meaning if I used an eclipse tranny like I was going to do originally, I'd have an exhaust manifold/turbo less than 3 inches from myseat back back, something that I'd rather not deal with for obvious safety reasons.

With a Neon tranny, I'd have the engine behind the passenger seat, plugs facing forward, lots of room for the turbo/intake/etc off the back. It also should bring my center of gravity back towards the centerline, which is where I want it. and since it looks like the diff is closer to the bell housing, I might be able to eak out a bit of width reduction from the current 56 inches in the back. Only measurements of the engine and tranny will tell for sure, but it looks like this will be my final choice unless there's a goot mitsubishi tranny that I'm overlooking. (I'm a bit brand loyal, but i'll go to the mopar side if they have better cookies :mrgreen: )

The Neon tranny's are also only 80lb (according to one site, Knuckshaft can probably chime in with the exact weight to an ounce if he wants to :) ) , so that and a 170lb 13B, about 50 pounds of alternator, manifolds, exhaust, and other general crap to get it going gets me to ~ 300 pounds total, minus fluids. I know it'll be more than that, but I'm pinching ounces at the design phase to hopefully keep it under 1500lb with me in it.

I think I can do that, I can calibrate a scale at 145lb, the frame shouldn't be too much (the current one clocks in at 140lb), tires+rims should be ~ 120lb, seats at ~ 20 each, figure 3 gallons of coolant at a pound a pint, or 24lb, 11 pounds of motor oil(6 quarts and change), 10 for wiring, ends up being ~790, leaving a nice margin of ~ 720 for the rest of the stuff.
I doubt brakes, hubs, suspension, driveshafts, body sheeting, pedals, dash, radiator, fans, etc will be that much...

End bran dump.
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
4g63mightymax
Site Admin
Posts:8017
Joined:Sat Mar 18, 2006 7:40 am
Location:MA
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 4g63mightymax » Sat Aug 07, 2010 2:43 pm

300D50 wrote: End bran dump.
Like Raisin Bran?

Bran will do that to ya.

-Jeremy
Jeremy N.
1964 Impala Convertible
1972 Pontiac Lemans
2016 Subaru Impreza

User avatar
vr4x4
HRCS OG
Posts:1702
Joined:Sat Dec 06, 2008 5:45 pm
Location:Nashua, NH

Re: The goes-way-too-f#$king-fast-mobile

Post by vr4x4 » Sat Aug 07, 2010 9:18 pm

Yes sir! High in FIBER!
Greg K.
1991 Galant Vr4
1988 Chrysler Conquest TSi (4g63 swapped)
1999 Jeep Cherokee Sport

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Sat Aug 07, 2010 9:24 pm

So my spelling (or lack thereof) is all you can comment on? Lame!

I do like bran muffins though...
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
vr4x4
HRCS OG
Posts:1702
Joined:Sat Dec 06, 2008 5:45 pm
Location:Nashua, NH

Re: The goes-way-too-f#$king-fast-mobile

Post by vr4x4 » Sat Aug 07, 2010 9:26 pm

haha, there is no way in hell I am reading that whole thing on my phone, I got to wait till I get on a real computer.
Greg K.
1991 Galant Vr4
1988 Chrysler Conquest TSi (4g63 swapped)
1999 Jeep Cherokee Sport

89coltgt
HRCS OG
Posts:940
Joined:Mon Jul 23, 2007 1:26 am
Location:Desoto, MO

Re: The goes-way-too-f#$king-fast-mobile

Post by 89coltgt » Sat Aug 07, 2010 11:41 pm

Interesting Walt. When I read mitsu trans bolted to a rotory, I immediately thought "I wonder if it can shift at the rpms the 13b could possibly rev at?" Good luck with the project, hopefully something will develope out of this.
John D.

89 d50
89 Colt gt

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Sat Aug 07, 2010 11:44 pm

I've got the rotary coming sometime this weekend hopefully :)
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Mon Aug 09, 2010 2:57 am

Hmm... seems a semi-readily available 6 speed is out there... the GM F40 from the 06 and 07 Pontiac G6. It held up behind a 400HP Buic V6 turbo swap, so it should hold up.

But is it worth getting an "extra" gear(and extra weight) when it's still only .71:1 6th with a 3.55:1 open diff, and no cheap lsd option?
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Mon Aug 09, 2010 3:26 am

Well, what tranny is better will be moot point. It'd still put redline in top gear at over 250mph, which there is no way in hell I'd even reach that once aerodynamics come into effect.

So it looks like it's just whatever is light, 5 speed, and has an LSD. Aka, Knuckshaft wins and I'll be searching for a Neon tranny! :mrgreen:

Feel free to tell my why I'm making a stupid choice or etc, I need to be pulled down to earth every once in a while...
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
300D50
HRCS OG
Posts:3868
Joined:Wed Jun 24, 2009 12:21 am
Location:Central NY
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by 300D50 » Mon Aug 09, 2010 10:55 am

Image

That's after shifting the engine to the passenger side. The COG is now a little more agreeable, moving the battery, tank, and final adjustment of the engine/tranny placement should put it dead center.

I decided to keep the current model for now, it's a good test mule for possible additions and whatnot. I'll make a "master" one when I have most of the parts I'll be using.
Walt
2006 RX-8 Shinka | 2006 BMW 325xi
1991 3000GT VR4 | 1994 3000GT SL
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

User avatar
Spicoli
Posts:554
Joined:Sat Aug 01, 2009 2:14 pm
Location:Kansas
Contact:

Re: The goes-way-too-f#$king-fast-mobile

Post by Spicoli » Mon Aug 09, 2010 10:45 pm

So what's the answer to colts question walt?

In my experiences a mopar trannys gonna take a S**t faster then anything.......
--keRby

Ad Inexplorta

User avatar
vr4x4
HRCS OG
Posts:1702
Joined:Sat Dec 06, 2008 5:45 pm
Location:Nashua, NH

Re: The goes-way-too-f#$king-fast-mobile

Post by vr4x4 » Mon Aug 09, 2010 10:52 pm

DOGBOX!
Greg K.
1991 Galant Vr4
1988 Chrysler Conquest TSi (4g63 swapped)
1999 Jeep Cherokee Sport

Post Reply