LocostUSA.com

OK. So, maybe it is getting to the point I should start this log? Building an autocross car. Started out to build a book frame however, a friend who is a much better welder than I and had made a few of these frames before, traded my stock for his "80% finished frame" (really, I think closer to 40% but, whatever) due to losing interest and wanting to start a mid engine build. The only issues is he is a bigger gentleman and started on a 442 frame. I originally was looking at a BEC build (and still might...) but am worried about the durability of a bike gear box in a car that will be launched HARD, frequently? Right now, I am leaning towards a 2.3 duratec with a 5 speed out of a Ranger. I have also considered a 13B rotary but as Mazda doesn't build them anymore and I don't have any experience with them, I am trepadatious. Presently, I have the frame (well, 40% of the frame) and a 1990 Subaru Legacy "donor". I liked the Legacy IRS however after buying it and learning more about the Subie's torque split, I am not sure it will hold up. Also, it does not have an LSD AND as it is an earlier edition, has trailing arms opposed to upper A arms. Not sure how that is all going to fit together but, we'll see what happens. Also as the Subie was 4WD, the front "spindles" have a big hole in them that leaves the bearings unprotected at the inboard section. So, in the end, maybe not the best decision for a donor but Miatas are far rarer than subies in this part of the country so, we'll see what we can get to work. It would appear that I am off to a poor start as far as low weight is concerned but even though it is a race car, I don't want to be fixing it EVERY week. I hope that the added weight will translate somewhat into added durability? Right now, I have SO MANY questions, I don't know where to start so, I will take a bit to mull them over and get back to this later. Thanks for taking the time to humor me. -George-

I would try to source a Miata. I built an EMod car which I just started racing last week.
viewtopic.php?f=35&t=14558 The Subaru parts are going to be much heavier everywhere. I used a Supra and although the car should have bullet proof reliability I am already over minimum weight of 1700 depending on weight distribution (1560lb car + 220lb driver) without any body panels on the car. The Miata has lighter LSD, Hubs, brakes, steering, axles etc. Something that will cost a lot to try and lighten later especially if you are going for DMod weight which is significantly lighter than Emod.

Also if you go with a 2.3 liter or a rotary engine you will be EMod, DMod is a 2.0L max (Rotaries are classed a 2.6 I think).

Good luck with the build.

_________________
2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Hi George, and welcome to the forum. Sounds like you're on the road to building a locost...

But you're gonna have to do a little more thinkin' about it. The Subie parts could be used to some extent, I guess. Other folks have used the diffs, I'm pretty sure. Don't think the whole system from a Subie (as in trailing arms and all) has been done. Not sayin' it can't be...

And, like Paul was saying, the upper limit for D Mod is 2 liters. Uncle Del Long, the godfather of D/E Mod, seems to be really excited about the Chevy 1.4 liter turbo. Locofinn in here is building one. That 2.3 Ford motor would be a good one, but it'll put ya in E Mod. Does that matter that much to you? I'd be more in favor of "build what you wanna build and then figure out which class it fits." Again, totally your choice...

Bet you can find a freeze plug/rubber plug/make something to cover those bearings in the Subie spindles... Or when you take that 2.3 and the trans out of a Ranger, snag the front spindles while you're at it. (And you COULD go for the stick-axle from the rear of the Ranger as well...)

Or, like Paul says, the Miata is a near-perfect donor. If you can find one anywhere nearby, that's a good option.

See what we mean? There are many avenues open to you right now. Figure out what you wanna build, and go for it. I'd suggest you read up on the SCCA rules for the class you want to be in, then look around in the Builder's Log section and read some logs others have posted for cars like you want. Then decide on donors/parts and start shopping. Then build sumpthin!!!

We'll watch and help... We may point and laugh too, but only a little, and we'll help...

JD

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

Yeah like JD said.
My only problem is I couldn't find a picture of 'trepadatious'

Welcome to the wonderful world of Locost building, where the only limits are your imagination.

_________________
Perry

'If man built it, man can fix it'
"No one ever told me I couldn't do it."
"If you can't build it safe, don't build it."

Perry's Locost Super Che7enette Build
Perry's TBird Based 5.0L Super 7 L.S.O
Perry's S10 Super 7 The 3rd
Perry's 4th Build The Topolino 500 (Little Mouse) Altered
Perry's 5th Build the Super Slant 6 Super 7
Perry's Final Build the 1929 Mercedes Gazelle

Oh yeah, George... I forgot to tell ya, Perry don't read so good. He'll need lots of pictures!

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

I'm liking trailing arms for these chassis. The only Lotus 7 from the factory with IRS that I've seen pictures of used trailing arms. They do a very good job of putting loads directly into the chassis in the directions the chassis is strong. With A arms you need to build a lot of structure to securely mount them and there are some devils in those details. My car is using them and SeattleTom has pictures of his car to help you see what you land up with. Plus look at lots of formula and race cars.

The Subaru diff is lighter than the Mazda unit and a high numerical ratio. It looks easier to mount, but has that long nose. Plan on ditching the sub frame, you're going to have to mount something either way.

Duratech is good engine choice. daunting to be up against turbos with it though.

Welcome, ( it's the holidays so I'm going to start drinking right away )

_________________
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.

Welcome to the forum. If you want opinions....you came to the right place.

I'll start the ball rolling....

"The only issues is he is a bigger gentleman and started on a 442 frame." Why not. These cars are really small and an inch here or there really can pay off later when you start stuffing it with a drivetrain and human flesh.

"I originally was looking at a BEC build (and still might...) but am worried about the durability of a bike gear box in a car that will be launched HARD, frequently?" No bike engines in SCCA D or E mod. They will be fine in B Mod. As others have mentioned, read the SCCA rules (free on-line) if you want to run with SCCA. It is no fun building a car that has no chance to compete if that is where you are heading with this build. BEC's are great for track days however!

"Right now, I am leaning towards a 2.3 duratec with a 5 speed out of a Ranger." Again read the rules of the club you want to run with. Duratecs are great motors with a lot of Mods available.

"I have also considered a 13B rotary but as Mazda doesn't build them anymore and I don't have any experience with them, I am trepadatious." I took the plunge with a rotary and learned a lot. The rotary is a very compact power plant with good power potential. A little expensive to build high power engines with very few pro builders out there. The fasted E Mod car in the country runs a turbo 13B and is crazy fast but a lot of money and development time was spent on it. I don't have unlimited funds or access to pro builders easily so I am now going with a turbo 1.4L Chevy if that tells you anything.

"Presently, I have the frame (well, 40% of the frame) and a 1990 Subaru Legacy "donor". I liked the Legacy IRS however after buying it and learning more about the Subie's torque split, I am not sure it will hold up. Also, it does not have an LSD AND as it is an earlier edition, has trailing arms opposed to upper A arms. Not sure how that is all going to fit together but, we'll see what happens. Also as the Subie was 4WD, the front "spindles" have a big hole in them that leaves the bearings unprotected at the inboard section. So, in the end, maybe not the best decision for a donor but Miatas are far rarer than subies in this part of the country so, we'll see what we can get to work." So many ways to go. No right way for sure. LSD is a must in my opinion. Also I like to keep it simple. many track only cars run simple live axles designs. They work fine for race cars and simple to design a correct suspension that does what you want it to do.

" It would appear that I am off to a poor start as far as low weight is concerned but even though it is a race car, I hope that the added weight will translate somewhat into added durability?" Heavy is sometimes more durable but not always. If you are going to get down to DM weight, you need to think light EVERY step of the way on EVERY component you add.

"...I don't want to be fixing it EVERY week." Don't worry about this. You WILL be fixing it every week. The idea is NOT to be fixing it during your track time!

I would join the Unofficial DM EM Yahoo Groups Forums. Many people that have been there and done that on that forum. All are very helpful.

At the end of the day, build what makes you happy and a car you enjoy driving.

Good Luck and keep us posted!

_________________
Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356

Thanks to everyone that has replied! I really did not expect so much of a response! But, I am glad for all the feedback I get. Don't be gentle. I can take it. I'd rather hear about it now than 3 years into the "tweaking" phase of the car! That having been said: sometimes, I'm not real bright. However I make up for it by being incredibly stubborn and very impatient (perhaps how I came to be in the company of said Subie?). Dont be afraid to tell me more than once if it doesn't sink in! With that being said, I don't know if I can respond to specific posts so, Ill try to get everyone in here as I go along.

Why not. These cars are really small and an inch here or there really can pay off later when you start stuffing it with a drivetrain and human flesh.
I have very short legs and (right now, at least) feel like I am drowning when I "try it on for size... I do that a lot! Ultimately, I want a car that feels like like my friend's F125 but, still be a "real" car.

As others have mentioned, read the SCCA rules (free on-line) if you want to run with SCCA
I am HORRIBLE at this part! Historically, I have bought / built what I like then tried to make it competitive in whatever class it falls in. I am sick of doing that so trying it the other way this time. Obviously, I need to work on it! I was / am leaning towards the 2.3 Ranger option because the powertrain could come out as one lump and "bolt right in"

I don't have unlimited funds or access to pro builders
-AMEN!- and while I enjoy the challenge of building it myself, I am not looking to reinvent the wheel. I figure I will stand taller on the shoulders of those that have come before. I understand the appeal of the chevy 1.4 unfortunately, they will be harder to source at this point (see "unlimited funds" comment, above) and I like what Caterham had done with the Duratec. Also, please forgive this next comment but if we are being honest, rotarys are dog ugly and for some reason (perhaps I am shallow or just don't "understand" them?) I can't get past that point. I understand however that this is not a "rational" arguement

LSD is a must in my opinion
Agreed. I will have to move to an LSD. For the moment, this one allows me to continue to move forward until I can source an appropriate carrier or pumpkin.

many track only cars run simple live axles designs
100% of the reason I started this build is because I am SICK of the live axle in my Mustang. I have spent too much time, money and "wasted" too many seasons trying to get that thing to behave properly. I'm DONE! If I cant have an IRS in this build, I won't race it.

...need to think light EVERY step of the way on EVERY component you add
ABSOLUTELY! ...Oh let me explain that "fixing it every weekend" comment: I don't want to be RE-fixing the same thing every week because the major parts I chose (trans, specifically, wont hold up)


I'm liking trailing arms for these chassis. The only Lotus 7 from the factory with IRS that I've seen pictures of used trailing arms
I haven't seen that so far... I do like them because it reminds me of vintage Indy or circle track designs. I am sure everyone on this site has seen the computer mock up of the vintage indy body that should fit right on a Locost Chassis? I WOULD LOVE for my build to look like that but doubt I am patient enough to get there!

Subaru diff is lighter... looks easier to mount, but has that long nose... ditching the sub frame, you're going to have to mount something either way.
I like the subframe right now because I think it will point me in the right direction for various mounting points. It wont be a permanent piece... I don't think? Have seen aftermarket subframes on subie sites that make me drool all over my keyboard

A turbo or supercharger is a forgon (eventual) conclusion for the Duratec..... Oh no! What will THAT do to the class I have to run in?!? Didn't think of that till right this second!

Perry don't read so good. He'll need lots of pictures!
Sory Perry. I will work on it! In the mean time, think of jumping out of an airplane using a 'chute packed by your "ex" = Trepadacious!

Bet you can find a freeze plug/rubber plug/make something to cover those bearings in the Subie spindles
BRILLIANT! I LOVE IT!

the Miata is a near-perfect donor. If you can find one anywhere nearby, that's a good option.
Closest one that makes sence is SLC (4+ hours away) then, I have to borrow a trailer to get it back (it is a shell). If I were a patient man, I could wait till one shows up locally but, that is a BIG if! My dad LOVES his Miata. I am sure he would catch on if pieces started coming up missing.... right?

Once again: Thank you for any and ALL feedback! I am reading and considering EVERYTHING at this point. As I mentioned before, I tend to get what I like then, make it fit. Historically, this hasn't always been the best option. However, I don't think I will get away from it COMPLETELY with this build. I have a fairly clear picture in my head of what I want this to look like (think Niki Lauda's Ferrari F1 car powered with the engines from the Millenium Falcon). My wife has a fairly clear idea of what I should spend to get there... somewhere in the middle those two ideas will eventually come together. In the mean time, I will listen to EVERYONE's input and lurk all over other pages but hopefully listen far more than type! PLEASE, keep the comments coming!

I'm assuming this is going to be a dedicated/trailered racecar? If you want to build a car that you can race without care for how you place, then your current approach is fine. But for all the blood, sweat, and tears that will go into it, if you want to build a car that you can be reasonably competitive in, then you'll need to increase the importance of the rule book and decrease the importance of convenience inyour build decisions. To be build a competitive car, you will need to read it, reread it, and reread it again. Over and over until you not only understand everything it's saying, but also everything it's not saying as well. Then maximize you use of each part of the rules to your best advantage as you design/build the car.

Regardless of marginally higher initial cost, the 1.4T will be more competitive in DM for less money than any allowed naturally aspirated engine. Ultimately it sounds like EM may be a better fit for you anyways though. With unlimited displacement and a higher min weight, there is more leeway in some of your decisions. A turbo Ranger Duratec drivetrain would still be on the underpowered side for EM, but technically at 2260cc would also keep you at a 100lb lighter min weight even after the 1.4x forced induction multiplier. So it wouldn't be all bad either.

What's the uncorrectable problem(s) you're having with the live axle in your Mustang, that gives you concern for using a different layout/configuration/geometry of live axle in a Locost?

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

To me, this was always one of most significant yet overlooked differences between a live axle and IRS. With a live axle, all the metal hanging off the back of the frame only has to support the fuel tank and body work.

It will be a dedicated car. I agree that I still have a LOT of research and work to do. This is my first build however and MOST important (to me anyway) is "getting one under my belt" After that, Ill probably go back and start again (maybe with a mid engine?). Hopefully this first car wont be an unmitigated disaster but I don't see it as my last build. It is a learning process. Regardless of what decisions I make, I am sure that when it is all over I will have ideas of what I could have done to improve.

Don't get me wrong, I think the 1.4 is a FANTASTIC idea! (I also like the idea of an ecoboost as I think we are going to see lots of great tuning out of that here shortly) I just think that it will be harder to find a donor car, get it hooked up to a rear drive transmission and the aftermarket support wont be there (yet). Volvo, of all people is also coming out with an incredible multi-stage turbo small displacement engine that makes me drool! SO MANY "options" at this point, could there possibly be a "right" answer?

The Mustang's main issue is traction. I have played with spring rates, ride heights, tire choices /sizes /pressures, pinion angles and panhard bars over the past 7 years and although I LOVE what we've been able to make it do after it starts rolling, I have NO grip off the line. If I could get it to "HOOK" like a drag car off the line, I could take 2 seconds EASY off of my time. The last option I have is a torque arm and although that might be the magic bullet, it doesn't change the fact that time marches on and I am starting to have a hard time keeping up with decent drivers in FS, let alone ESP. It seems to me that the money I would have spent on a torque arm was probably better spent on a chassis and a donor. In the mean time, I will limp around in the mustang for the next year and probably have a bout of cognitive dissonance when I finally retire it.

As for the chassis on the Locost: I tend to get a good vibe when I watch Mr McSorrley's videos on chassis set up. I LOVE the idea of the variable angle settings on the top A-arm but was wondering if using the same method on the bottom A-arms would also be a good idea? That way, If I started out on a tire with a 22.8 diameter and then went to a larger diameter tire, I could adjust the lower control arm to keep the arm parallel to the ground. OR, the other way if I went with a smaller diameter tire. Is this a good idea or am I missing somthing? Does anyone else have input on his approach?

Thanks again for the feedback! Everyone I know here is TIRED of hearing about my car ideas. It is great to have people who understand!

Nice point nick! Never stopped to think of that (and lots of other things yet, I am sure) so, why is that type of set up not more popular?

That was something I thought too. Then it really clicked for me when I saw a picture of Modernbeat's car on it's wheels with the entire car behind the driver chopped off.

With trailing arms the forward and braking forces are fed into the side of the chassis, which is very strong that direction. All the cornering force is fed into the bulkhead behind the driver with a single upper link and a reverse wishbone at the bottom. All the torque from the brakes go straight into the trailing arms and they are very strong at that. It's easy to figure out if this stuff is strong enough. If you are using wishbones it's just more complicated. We've had people measure their lower wishbone flexing a couple of inches with the brakes on.

Duratechs are great little engines and are very light. I think I weighed one at 200 lbs. in the engine weight thread. I am not sure it's a good choice for boost though, there are reasons it is so light! If you are going to go boost, start with an engine with stock boost. If Ford Motorsport sells a supercharger for it, then I wouldn't worry too much. I can ask a friend who builds them for racing, he will know right away. For instance my Formula Ford ( Kent pushrod motor ) engine won't take boost because the cooling passages between the block and head are right next to the cylinder.



Well your building a frame, so it can do what you need. By all means use the sub frame for a placeholder while you figure things out.

_________________
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.

You, and everybody else. Even setup and tuned for handling, I would expect a live axle should be able to hook off the line better than a typical IRS. So that makes it even less obvious what you're hoping/expecting to gain from an IRS.


I'm not trying to push you this direction, since you're probably looking at EM more than DM anyways, but if you haven't already, read this. Chevy Sonic/Cruze engine + eBay bellhousing + T5 + tune. A turbo engine has to breathe through a 33mm restrictor in DM, so any other aftermarket support concerns would be items of diminishing returns anyways. Yes a 2.0L Duratec can be built to ~300 crank hp, but that is an engine that costs significantly in the neighborhood of 2x more than most of the 'nicer' finished cars on this site. But even to get a DM compliant (naturally aspirated 2.0L) Duratec to simply meet or exceed the 1.4T performance level would be significantly more effort and cost, as it would still require a 'built' engine just to break 200whp.


For reference, the pics can be found here.


Cosworth used to sell a nice dedicated MP62 roots blower setup with an air/water intercooler for them. It can still be purchased through Flyin Miata with the Cosworth name machined off the casting, and Flyin Miata machined into it. Supposedly takes an NC Miata 2.0L into the 230-250whp range, but not exactly cheap either though. Also the throttle body would probably stick out of the hood on a Locost, but it is still available nonetheless. Like many (most?) modern naturally aspirated engines, stock they're good for an easy 10-12 psi on a relatively small (quick spooling) turbo, but probably should get better internals to take it much further. As usual, beyond that point it's mostly a matter of how deep your pockets are as to how much power you can make, not that peak power is what autox cars are chasing either.

Turbocharged stock Focus 2.3L:



But no, it's still never going to be the engine of choice in EM, and again is probably still not the best bang for the buck if wanting to get into a truly competitive state. If going turbo anyways, finding an engine with forced induction from the factory will typically be dollars ahead of starting with a naturally aspirated engine. That being said, it still seems like it might fit the goals of this build just fine too.

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

Im going to chime here and give a few things to think about...

First like other said read the rule book... your lucky the D-E mod section is not as painfull as the stock section

Join the D-E mod Yahoo list.... ask questions theres a lot of experience there and most are not affraid to share to ask.

The 2014 DMod winner has a 2.0 liter Duratec with Cosworth goodies. Not cheap more like expensive but one of the best engine in the field... He was selling his spare a while ago... check the for sale section for an idea on cost. p.s. the focus have 2.0 duratecs. So no issues on getting engines cheap in the junkyard... getting them to make power in D-mod jacket range is $$$$$$$

The 2 fastest Emod have solid axles. And they run between 350 to 400hp. Check out Jeff Kiesel sprite and Steve Brueck Jeep on you tube.

The fastest DMod locost whit multiple championship win has a solid axles. Its also for sale at half the price it would cost to build the same thing. Check out the for sale section

In race conditions the only real advantage IRS will have is adjustibility and unsprung weight. You can mount your disc inboard. BUT... my limited experience running a locost in Dmod is you really need a higher roll center at the back to make the front end hook. Much higher than the tipical IRS intallation... this is the reason why i ditched the mumford link for a panhard bar.

As for the chassis. This piece is the one that takes the least amount of time in you build. It will be modified... you will cut some piece off put new pieces... Where do you want to be in pecking order of the class. .. a 442 is not a solo 2 car.... just the wheel base is off... the fastest EMod are 80 inches... the Dmod 88-90 and one being built at 80... a 442 will get you at 94... I know one 442 chassis got chop up in 4 pieces after a season of solo 2 to make it back as a book chassis.

Im not trying to rain on your parade... Im just trying to tell you that Ive screwed up a lot on my builds by not thinking this enough... yhea we all want to cut the steel and weld it but this is the first mistake.

Building a Dmod is about building something out of the box of car building... weight is your enemy... So stay away from Mustang 2 spindles. Vented disc steel floors. 1/8 thick brackets for non structural items... Think legend cars for front uprights, brakes, steering. If you really want IRS there is a nice design floating around the internet, and yes your could use the Subaru diff...

Cheers

Fred