SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
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Post by SeattleJusty on Nov 4, 2009 17:44:32 GMT -5
I wish I could put what you just said onto the home page for new members to see as they're registering on these boards. Something like if you don't like A, B, C, D about a Justy, then buy an Audi/Impreza/Porsche. It'll be less expensive, twice as fast and probably more reliable.
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Post by onsk8 on Nov 4, 2009 18:53:51 GMT -5
Some intake thoughts. You want to use three carbs on the intake. This mod seems like it would be great for high hp, but not low torque. can you run really long runners with a triple carb setup? i have never seen one.
Diff thoughts. I personally like the locked center. Crazy thoughts but anyone know what the dccd units look like that would be the ultimate solution in my mind. Tune it as you need it.
On the turbo issue. i think it would be worth it. a turbo can net you at least 40 hp. so 40 hp over 600 pounds = 1 hp per 15 lbs. A standard justy is roughly 1 hp per 27 lbs. assuming 110 hp that would lower you to 1hp to 22 lbs. Also with the ballast you can put it where you want it to make the car balanced. Mind you youll lose some nimbleness but you will have a better power ratio to compensate. On the other side, look at frank sprongl and his swift. He placed third in a national event. so maybe keep the weight down and maximize corner speeds.
another bonus with the turbo is you get a neeto wooshing and humming noise.
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SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
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Post by SeattleJusty on Nov 4, 2009 23:07:14 GMT -5
Some intake thoughts. You want to use three carbs on the intake. This mod seems like it would be great for high hp, but not low torque. can you run really long runners with a triple carb setup? i have never seen one. Diff thoughts. I personally like the locked center. Crazy thoughts but anyone know what the dccd units look like that would be the ultimate solution in my mind. Tune it as you need it. On the turbo issue. i think it would be worth it. a turbo can net you at least 40 hp. so 40 hp over 600 pounds = 1 hp per 15 lbs. A standard justy is roughly 1 hp per 27 lbs. assuming 110 hp that would lower you to 1hp to 22 lbs. Also with the ballast you can put it where you want it to make the car balanced. Mind you youll lose some nimbleness but you will have a better power ratio to compensate. On the other side, look at frank sprongl and his swift. He placed third in a national event. so maybe keep the weight down and maximize corner speeds. another bonus with the turbo is you get a neeto wooshing and humming noise. Wow. What a post. - You want to use three carbs on the intake. This mod seems like it would be great for high hp, but not low torque. can you run really long runners with a triple carb setup? i have never seen one.
If all other things are equal, individual carburetors for the cylinders, will offer better performance potential for torque and thus for horsepower, throughout the rev range. The only time that you would lose torque or tractability would be for the same reasons that you would with a single carburetor; poor tune or improper jetting/emulsion tubes for the application. The drawback is balancing multiple carburetors and all of the additional hoses/manifold/wheredafarcledoesmythermostatgo problems you have to solve.
- can you run really long runners with a triple carb setup? i have never seen one.
You can use any intake manifold runner length you desire but you should do some math on resonance to get the best results for your desired RPM and exhaust lengths.
- a turbo can net you at least 40 hp. so 40 hp over 600 pounds = 1 hp per 15 lbs
40 into 600. My what an interesting number you choose. A turbo could yield you much less than 40 HP or much much more. Yeah Justys have a power to weight ratio of 23-28 LBs per HP on North American cars. The stock Gen1 GL weighed 1785. I don't know if the rally prep'd car weighed more or less with the deleted interior and steel roll cage but a 1785LB Justy would need 715 LBs added to make the 2500LB minimum weight of which Matt made mention. Call me wacky but I just can't see the benefit of 110 theoretic HP in a 2500LB Justy. Sounds like back to square one but with less turning ability, unwanted under hood temperatures, added expense in the build and probably less reliability. Oh and also, that's another 700+LBs to engineer into your brakes, your suspension, your wheels and tires. Ugh. Might as well campaign a Volvo instead. Then again, someone like Jeremy could probably make it work. Since it's a racecar he wouldn't even have to explain or justify his preferred method of crankcase ventilation.
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Post by onsk8 on Nov 5, 2009 0:04:27 GMT -5
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Post by indkid87 on Nov 5, 2009 13:46:58 GMT -5
Was anything done to the suspension on that car to get it to hold up to the rally abuse?
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Post by madmatt on Nov 5, 2009 16:47:13 GMT -5
Indkid87,
The suspension uses stock dampers, but we used an adjustable coil over sleeve and 185 lb springs in the front (I think 185s...)
The rear uses 250lb springs (remember they are inboard of the wheel so a higher spring rate is needed due to the lever arm) mounted in a custom, height adjustable mount.
The front trailing links have had the bushing modified to reduce the 'slop' under braking. Basically I cut away half the bushing and used huge big washers on either side of the mount. Someday we might go solid there. We run without the front sway bar for better inside wheel grip but a bit more ‘lean’, although the car corners pretty flat with the stiffer springs.
Front strut tops are seam welded and a strut-brace ties into the firewall. The cage comes through the firewall as well and is tied into the top of the strut mount.
The rear is tied into the cage as well. This seems to be the weak point for most cars. I've seen the rear shock tops rip out of Justys... but not ours so far.
There have been plans to fab up something better, but it works pretty well as is. We could use more dampening, but that means going custom. There is a guy in Seattle that does custom upside down rally struts for decent prices, he said he would create something if we decided to go that route. Justyracer found some Porsche Bilstein (I think) struts that fit in the rear, but I'm not sure from what model, and I don't think he ever ran his car again after finding those.
So basically it is stock with stiffer springs. The big deal with Gen 1 bodies for sure is to beef up the strut towers and mounts to deal with the abuse.
Matt
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Post by indkid87 on Nov 5, 2009 17:13:36 GMT -5
Thanks for the info I was thinking of beefing up the mounts and adding strut bars to my gen 2. Where did you get the stiffer springs from I'd love to harden mu suspension a bit. I also have problems with the front trailing links my winter tires rub pretty good on the wheel wells under hard braking.
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SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
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Post by SeattleJusty on Nov 5, 2009 17:43:41 GMT -5
Listen, if there's one thing I've learned after hanging around here nearly 5 years is that having control over one's project is important, sometimes even more important than getting it right. Very good point, Stacks. That makes me wonder how that Justy powered buggy is coming along. The one that was supposed to be reverse running and I said "ain't happnenin'".
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Deleted
Deleted Member
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Post by Deleted on Nov 5, 2009 22:46:38 GMT -5
While Ferox & I seem to butt heads over which end of the pump shaft bears more load... ?Stacks, no I feel the design is an improvement over stock Indubitably
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Post by hollandjusty on Nov 6, 2009 5:27:54 GMT -5
We run without the front sway bar for better inside wheel grip but a bit more ‘lean’, same here ;D I've seen the rear shock tops rip out of Justys... A well.. did happen to me. It might be the reason why i lost 1st place here. (you won't notice the rear shock top rip out) www.youtube.com/watch?v=0RWRJE88OhQ
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Post by ultima on Nov 6, 2009 12:42:12 GMT -5
I've seen the rear shock tops rip out of Justys... A well.. did happen to me. It might be the reason why i lost 1st place here. (you won't notice the rear shock top rip out) www.youtube.com/watch?v=0RWRJE88OhQWell that happened to me too, thought it sounded a little wierd going over bumps in the road
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Post by xtremzj on Nov 7, 2009 17:18:12 GMT -5
awesome another rally justy on here. specs on cage? no front sway here eaither, but i gotta weld the strut mounts up...eek
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Post by madmatt on Nov 9, 2009 10:11:54 GMT -5
xtremzj, The car is built to CARS (canadian association of rally sport) specifcations. The specs are downloadable from the site mentioned by onsk8: www.carsrally.ca/CARSRally/Portals/0/CARS_2009_En.pdf I saw the pictures of your car (didn't see a cage in there), and if you are just rallycrossing it, caging adds alot of work and weight you don't really need (it will slow you down more then speed you up). The lower speeds you run, plus the lack of obstacles really negate the need. If you are planning on running a real stage rally though don't use the CARS site, you need to contact you local scutineer; get a hold of either Rally America (www.rally-america.com) or NASA rally sport (http://www.nasarallysport.com/main/) for more information. Even though we (CARS vehicles) can run in RA events, and vicea-versa the car needs to meet your local sanctioning body specs to get a logbook. There is currently lots of 'cage controversy' over things like how you build the door braces and what sort of gusset material you use. This is why you need to get to know you scutineer. Also I believe you mentioned you put in a fuel cell... this will be a huge pain, as RA is trying to follow FIA rulling to the word and there is a lot of problems trying to mount a fuel cell in a hatch back right now (legally). The box needs to be in a box, and the filler needs to be in a fireproof box, some are then saying you need another firewall between the drivers and the tank. Best to stick with the stock tank... imo. Reinforcing the shock towers might be of some help if you're local rally crosses are bumpy. The Gen II cars are stonger up front then the GEN I's. The rears are still weak. Matt
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Post by xtremzj on Nov 9, 2009 13:00:53 GMT -5
good info thanks, i was told by a fellow racer that i just had to have a fire proof box around the cell. i will look it up tho. the old cage in the justy was from NASA specs, and need to update. i also heard the door braces were going to be a latter instead of a X. ya i mostly do rallcross but have done stages also, and want to get back into it. thanks for the info, hope we can trade secrets...
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Post by madmatt on Dec 5, 2009 21:44:15 GMT -5
RedRoo asked in another thread if I'd made any progress. Rather then completely derail that thread (we'd already lost the caboose!) I thought I'd post what bench racing had been done to this point.
We've got a hold of a set of Keihin carbs from a Yamaha genesis motor. These are a standard motorbike/snowmobile carb that normally mate up to a 3 cylinder 4 stoke 1000 cc motor that makes 120+ hp. The same carbs have been used quite effectively on the toyota 4AGE (those crazy brits are doing awesome things with bike carbs) which per cylinder is 'similar' to our displacement. The spacing of the carb bodies is a nice close match so I should be able to make up an intake with ease using part of the original intake. The issue will be dealing with the water jacket. I'm hoping to be able to sort something out (any thoughts folks, this is a carbed intake).
The car is still 600 km's away... so I'm working from memory and via e-mail with my co-driver (who's presently storing the car). There's no way we'll be back on stage until next summer, I need to get shop space sorted before I can move at a reasonable pace. I'm planning on picking up a few spare heads, the carbs and some intakes over the holidays. Then I'll be set to fiddle in front of the TV while my partner makes strange faces and tells me I'm weird ( I wonder if she'll mind if I start porting the head in the living room?)
Matt
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