LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently Fri Oct 31, 2014 6:52 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 50 posts ]  Go to page 1, 2, 3, 4  Next
Author Message
 Post subject: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 6:36 am 
Offline

Joined: Mon Feb 20, 2012 2:51 am
Posts: 23
G grand T touring R roadster
i whant to use this car for week end trips and long drives.

GOALS for book chassi car
1. 40+ mpg
2. 200 Hp per. ton
3. Under 7k build cost

origanally i thought Pinto spindles, F20 S2000 motor and trans, toyota rear end 3.90 gears stock 4.11 in s2000 and taller skinnier tires apx 195 65 15 or 16.
well what do you think. the engines to tall. so options to hit my HP goals and MPGs that will fit under the hood better.
lighter and or cheaper spindles and brakes.i know i know you cant have bolth. i dont have any front end parts at this time. if any one has a better idea please jump in.
i have a toyota carolla rear end. no idea what gears are in it. but i thought theres no way there has deep has the stock honda rear end. brake backing plates measure apx 48 across. not sure if this rear end is narrow enough. any thought are welcome.
i have a shop full of tools. so my budget is for hard parts.
this is in the planning stages. i figure a good plan is the only way to get under my budget. so iany ideas are welcome.


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 8:35 am 
Offline
User avatar

Joined: Sat Sep 26, 2009 8:25 pm
Posts: 879
Location: Park Hills, KY
I think your power to mileage ratio/ goal is a bit skewed... There isn't a 160 hp motor on the market that get 40 mpg's, especially if paired with either of those rears. That hp number is derived from the heavy end of the typical Locost scale... For that kind of mileage, you might want to check out Jack Mcormic's build....*I know I just butchered your last name, sorry Jack...* aero will be key in hitting high mpg numbers... But it won't be quick, comparitively speaking...


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 8:50 am 
Offline
User avatar

Joined: Sat Sep 26, 2009 8:25 pm
Posts: 879
Location: Park Hills, KY
Didn't mean to hit post yet.. lol there is a guy on here using a 3 cylinder geo metro engines and trans in a middy build that very well could hit that mileage number
with a little aero work...

There are turbo parts available for those engines too...


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 10:57 am 
Offline
User avatar

Joined: Thu Jul 17, 2008 9:11 am
Posts: 3071
Location: West Chicago,IL
My Locost is at 228HP per ton and I get 20mpg no matter how I drive it. Local roads or highway doesn't make much difference. Of course I have a fuel sucking rotary and I don't generally drive it nicely. My DD is a 148HP Elantra (~105HP/ton) that gets a highway EPA rating of 40 MPG. But that is a 6-speed auto with today's technology etc. If I actually drive the Elantra at 70mph vs 55-60, the mileage drops to ~35mpg. And that mileage drops significantly more if there is a headwind. Aero is king for highway driving.

Weekend trips and long drives in a Locost is your intended use? Aero,aero, aero! To get anything close to 40 MPG you will be looking at either Jack's traditional Locost bodied MAX with a turbo diesel (he was getting 50+MPG in that configuration), or a car looking very different from a Seven like Jack's rebodied MAX (>100MPG under controlled conditions). You will have to decide if you want the look of a Locost or the 200HP/ton thrill. I don't think you will be able to have both. I can imagine maybe a 80HP/ton and 30+ MPG gas powered sevenseque vehicle. But I have no real basis for thinking that. Anybody else with a sevenesque meet those 200HP/ton and 40 MPG highway numbers at the same time?

Your $7K goal is doable if you work from a single donor, don't farm out a lot if work and don't rebuild mechanicals too much. Not counting my engine rebuilding costs and replacing new brake stuff where the existing would have done just fine, I was in about 4K. That can easily creep out of control with buying stuff that is "nice" to have rather than "necessary" to have, like classic gauges or wheels & tires or FuelSafe gas tanks or Wilwood pedal assemblies with dual-master brake cylinder , or...... You get the point?

It is good to have goals. That helps keep us on the intended path. How hard and fast are these 3 goals? Or are they "stretch-goals"?

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 11:19 am 
Offline
User avatar

Joined: Sat Sep 26, 2009 8:25 pm
Posts: 879
Location: Park Hills, KY
Shizzam....

viewtopic.php?f=36&t=12988


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 2:24 pm 
Offline
The voice of reason
User avatar

Joined: Thu Jan 10, 2008 4:47 pm
Posts: 5804
Location: Massachusetts
Welcome to our forum if you haven't got that yet.

Your goals seem reasonable, but will require effort. What's life without goals?

If you can keep your car down towards 1300 lbs. then the power to weight is pretty easy and there will be plenty of economical engines you can use. Most econobox type Ford Focus etc. would be fine.

For price scrounging and making/adapting parts becomes key.

MPG would take some work, but if you look at what Jack did - which is build a locost and enjoy it and then build an aero body - you can see there are many paths to that goal.

Spindles is an example of the choices you have. Pinto and Miata spindles are about the same weight and have similar geometry. Spitfire spindles are several pounds lighter and are commonly used in Britain and race cars etc. They require modifications and are available from different places but cost more. You'll have to decide what resources are available to you.

With no donor, Pinto spindles, Ford Duratech engine, Ford Ranger transmission and your solid axle would work. Considering your weight and gas mileage interest I would try to find an axle with the highest gear possible ( numerically low gear - even under 3;1 would be good ). First gears are often low and you will be able to hit the rev limiter in about 1 hearbeat from a standing start - that should be good enough.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 8:06 pm 
Offline

Joined: Mon Feb 20, 2012 2:51 am
Posts: 23
thanks for the input guys.

Rx7locost- thought of the metro motor samari trans. didnt think i could hit the power goals or at least not for the same type of money that a bigger engine might have to start with.

goals are set as just that goals. trying to hit all of them but opperation costs are king. mpgs are number one. i dont think i would realy know the diff between 170 and 200 hp per ton. but why not shoot high.


Horizenjob- thanks for the welcome. 300 gears and bad aero might not yeld the mpgs desired if the engine is working to hard at 65. dont know a hole lot about alot of engines but my gear and tire choses were based on higher gears over the stock ones by a mild amount and 2 to 3 inche taller tires. basicly rasing the rear end gears for lower rpms on the freeway. as well as narrower tires for less roaling drag. im sure this is the same train of thought as what you said just worried about over gearing a motor like the f20 that has very little torque. a friend of mine brought the fiat 124 spider to my atention for the spindles and rear end. not sure if these are as good of a choise but the hole car could be had real cheap. not realy sure about the 1800 engine only 25 mpg from the factory. 40mpg seems a long ways from there.

spoke with jack ones from kenitic hes out here in oregon not a realy rely far ways a way but still a ways out there.


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 9:21 pm 
Offline
Toyotaphobe
User avatar

Joined: Sat Apr 05, 2008 2:25 am
Posts: 3304
Location: Fort Worth, Texas
If a Miata engine will do it so will the F20.

Pulling more weight (about 400 lbs) my S will outpull my Miata in every low rpm pull we have been able to devise and once VTEC hits well it's all over for the Miata.

Most people base the low torque from the feel. The difference between on VTEC and off is so great that it feels like the motor is barely pulling by comparison.

I did the same low rpm pulls against my 350z and it ate my lunch, but at drag launches or any other type of higher rpm or fast runs the S ate the Z's lunch.

The AP2 trannies have a higher cruising 6th gear (it's not really the gears but there's a 5% reduction in rpms)

_________________
mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 10:01 pm 
Offline
User avatar

Joined: Sat Apr 26, 2008 6:06 pm
Posts: 2206
Location: Under the weather. (Seattle)
So you want cheap, fast, AND reliable...

Operational definitions are critical when setting specific targets like this, namely on your "200 hp/ton" measure. By hp do you mean bhp or whp? Are you measuring the weight as curb weight (car with fluids), curb + driver, curb + driver + weekend/trip luggage, curb + driver+ passenger, or curb + driver+ passenger + weekend/trip luggage? These will have significant effects on what it will take to reach your goals. If it's bhp and curb weight, the S2k engine is overkill anyways, provided you're sticking to a reasonably traditional Locost design...I'd imagine that will also blow through your proposed budget pretty quick too.

_________________
-Justin

Also follow my build on blogspot, tumblr, or instagram and twitter (GarageOdyssey)


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sat Mar 10, 2012 11:00 pm 
Offline

Joined: Mon Feb 20, 2012 2:51 am
Posts: 23
carguy123- great to hear from an s2000 owner. ok so the honda has more pull than the miata. i was under the impression that the S came with 4.11 gears? do you think that 3.00 gears would be to much. a friend of mine said his old S pulled 31 to 33 mpg on the freeway. is this about the same mpg you are getting. one more thing if you would. im also under the impression the S came with 205 55 16 front and 225 50 16 rear. is this correct?

Driven5- 200 hp per ton is an apx of what my old 5.0 was. dont know real numbers. 351 windsor race engine on pump gas apx 380 hp, full interior and two ocupants. would love this car to run like that. i have a line on an S for 4000 that was backed into a wall. thinking maybe i could sell the parts off and keep the motor, trans , complete wiring harness and steering collum.

thanks all


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sun Mar 11, 2012 12:22 am 
Offline
Toyotaphobe
User avatar

Joined: Sat Apr 05, 2008 2:25 am
Posts: 3304
Location: Fort Worth, Texas
Technically they did come with those tire sizes but they were specially sized, especially the rear, they were bigger than the rated size.

Having driven numerous S2000 powered Locosty vehicles I'd say that with that little weight it just might do it. I'd be scared to try it in an S2000. But I'd still be worried about hills.

I haven't paid attention to the gas mileage since the car was new. The mpg I remember the most was driving 80 miles to an autocross for the S2000 club, running all day long (small club LOTS of seat time) driving home and still averaging almost 25 mpg so I guess 30 mpg on the highway is possible. I just don't care. The mpg could be 14 and I'd still smile everytime I drove it.

I can get you the height of the engine tomorrow. I have a complete S2000 stripped down to just about all it's component parts in my shop.

_________________
mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sun Mar 11, 2012 12:30 am 
Offline

Joined: Mon Feb 20, 2012 2:51 am
Posts: 23
engine highth would be cool


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sun Mar 11, 2012 10:35 am 
Offline
Toyotaphobe
User avatar

Joined: Sat Apr 05, 2008 2:25 am
Posts: 3304
Location: Fort Worth, Texas
any other dimensions you want? I'll get them after church.

_________________
mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Sun Mar 11, 2012 5:29 pm 
Offline

Joined: Mon Feb 20, 2012 2:51 am
Posts: 23
length of engine, bellhousing width and depth would be great.
thank you


Top
 Profile  
 
 Post subject: Re: planing the G.T.R.
PostPosted: Mon Mar 12, 2012 10:33 am 
Offline
User avatar

Joined: Wed Nov 12, 2008 6:29 am
Posts: 3406
fastmonkey wrote:
engine highth would be cool


Once you find that out I guess that's why you will be "planing" your G.T.R.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 50 posts ]  Go to page 1, 2, 3, 4  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY