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Post by madmatt on Oct 30, 2009 20:55:14 GMT -5
Hello folks,
It's been a long time since I posted here. I used to race a '88 Justy in the OPRC (Ontario performance rally championship) and had two decent seasons with the car in '04 -'05. I f you look back through the rally pages there are a few posts chronicling the build and results.
We're thinking about hitting the stages again, but P1 the class we raced in is gone. To stay in production we would be mixing it up with 1.8l cars and above.
Given various problems we had, I'm thinking about running Open Class, which allows for lots of problem solving. Problems including sufficient oiling, cooling, braking and of course... power. While I should start with the first and work towards the last, power is always more fun to bench-race-chat about, and I thought I would garner serious thoughts.
Here is the motor plan;
port/polish/deck head grind up a cam worth running, run cheap junkyard bottom end (have a few left) with fresh oil pumps. build a intake headed and run the infamous 3 mikuni carb set-up.
My questions are:
Does anyone have cam specs for this engine running 11:1 or so compression and free flowing intake and exhaust (we run a flow through aftermarket cat)
I know the infamous landspeed car ran big carbs, but I'm looking to build torque, not wide open throttle RPM's so I'm thinking 32-36 mm any thoughts? (Yes I'd love to run throttle bodies and mega squirt, but I have cheap - read free- access to carbs)
Next big question:
Has anyone been able to source a close range gear-box mod or at least lower final drives? Engines I can wrap my head around, but I've never torn down the Justy's tranny and I'm unsure if there's something else that would fit in the housing...
Cooling is easy once we're in open, any junkyard rad I can find that will fit behind the grill will solve that problem (can't run anything but OME in production...), brakes same, just a simple upgrade to gen 2 hubs discs and old Volvo calipers with some brackets.
Anyone ever stuck a Jeep vicous coupling on the rear driveshaft?
This is bench racing until I can find a shop near my new digs, and get some local resources in line for machine work etc. But any thoughts from the experienced engine builders here would be wonderful.
I should add, I can't turbo it. Rules state for a a turbo AWD/4WD car, mim real weight must be 2500lbs, it would be silly to add a turbo, just to then slap 600lbs of ballast in the car...
Cheers,
Matt
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Post by RedRooJusty on Oct 30, 2009 23:39:21 GMT -5
**madmatt** I have been doing some research over adding a Viscous Coupling into the rear drive-line. I have found that most Jeep units are transfer case integrated. In-line VC's are kinda elusive, I did find that land rover (although pricey) uses a driveline integrated Viscous Coupler in the freelander model. I ebay'd and popped this one cgi.ebay.com/ebaymotors/LAND-ROVER-COUPLING-VISCOUS-TRANSMISSION-DRIVE-UNIT_W0QQitemZ140231375433QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item20a670fa49 I have seen this unit go from 350 - 400 - 450 over the last few weeks, but it could definitely handle rally abuse. Suzuki has some in-line VC's as well, I just can't find them anywhere. Subaru ~90ish GL's have Viscous limited slip rear diffs, I just don't know if I can get gears to match the justy front diff ratio. I am still researching though, I am just giving you ideas in hope you will do a VC mod and maybe give me some pointers on what fun it took to fabricate it. My goal is to give my justy the option of wet/dry AWD (over 50/50 4WD). --good times Eric
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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 Oct 31, 2009 1:34:34 GMT -5
Subaru ~90ish GL's have Viscous limited slip rear diffs, I just don't know if I can get gears to match the justy front diff ratio. Switching out the Justy's rear open differential for a viscous unit will give you better traction in theory but this will in no way solve the how-do-I-use-my-Justy-in-4WD-all-the-time-or-on-dry-pavement situation that everybody is always talking about. The point of adding an inline viscous coupling is to unlock the front axle from the rear axle so that the front wheel can spin at a different speed from the rear wheel. Putting a viscous rear end in a Justy does not unlock the transmission. The J10/J12 transmissions are locked. I hope this helps.
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Post by madmatt on Oct 31, 2009 9:27:54 GMT -5
Red Roo,
That LR coupling looks very similar to the Jeep one I held in my hand once... out of a mid 90's Cheeroke or something I was told. I've also been told the Toyota used an in-line unit in a few machines. The deal with most drive line VC's is even if they were 'meant' to be in the transfer case, you can build a mount like seen in that picture and run them in the open (so the Jeep guys I talked to told me) Several folks suggested mounting one directly on the rear diff yoke to avoid needing two bearing supports.
The VC is not the biggest issue to deal with however. There are very few pavement stages in North America (only Defi north of Montreal I believe) and most of the time we're sideways and spinning so who cares right? I will keep my eyes open, and report back if we do fit one.
SJ,
I actually spent some time in Seattle (2yrs), man I miss that place! Yes the limited slip rear won't do anything for the locked in place 4WD... and we have a welded rear diff if we ever need it(have never used it, but may if we run a winter rally this year).
Stacks,
I am from mid-western Ontario, but have moved around a bit... I'm in Montreal now. Close to 'Justracer' whom I never got to go head to head against when he was running his, asnd I guess not far from you. I was very impressed with your resourcefulness on the oil pump issues, how is the modified pump working? I've been toying with using an external (not dry sump) oil pump, but thinking that I just need to get some fresh new parts. I'm not sure, my fabrication skills are more limited to hammers and welders rather then lathes and mills...
Cheers,
Matt
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Post by RedRooJusty on Oct 31, 2009 11:44:11 GMT -5
. Putting a viscous rear end in a Justy does not unlock the transmission. The J10/J12 transmissions are locked. I hope this helps. **SeattleJusty** this does help. Incorporating a Viscous Coupler into the rear drive line would solve the front to rear lock. I was getting the impression that you do not favor this kind of mod. Can we get a "4WD" category in the Mods board? thank you. **madmatt** Jeep did make a in-line viscous coupling? I will have to add Jeep to my search. l love hearing of your continuing rally ambitions, Please keep a blog / website / flickr of your mods and racing. I am a fan. -sorry to hijack your thread, you just touched on a mod that I am very interested in. **stacks** (the R-160 is 3.700, hmm...oh this is good stuff) I have found a couple of "factory" made diffs that have a Viscous Coupling being used as the slip mechanism in the LSD like the svx rear diff 93-95 (although 3.57 geared) for example. But to be fair the diff-incorporated device requires a ton more force and really is not designed to allow both rear wheels to slip together, as this would be a necessity to unlock the F/R diffs. I am still looking to just VC mod the drive line in my project. For on-the-fly (rally) track transitions from dirt to dry the ViscousLSD gives a distinct handling advantage in avoiding under/over-steer. -good stuff fellas
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Post by madmatt on Oct 31, 2009 13:51:39 GMT -5
Red Roo,
That was not a hijack! It's the sort of discussion I'm looking for.
The problem with a VC is the inherent design flaw for what I believe to be your's and my uses. It is reactive as opposed to active, meaning that it is "open" until things start to slip. So let's say we do the easy VC inline mod.
Your on pavement, there's enough slip to let you turn etc. but the torque is being sent to the front wheels first, because basically we just cut the rear driveshaft in half. This works not bad if you're coming home from the grocery store and you run into a creekbed and need the rear wheels to get you out, but you've lost the oversteering provided by the rear wheels being driven, until things start to slip to lock up the goo. (where's the fun in driving a underpowered front wheel drive, sometimes rearwheel drive machine).
Now you're on gravel, on stage and the drifting around, my guess is the goo (depending on its shear characteristics) is going to lock up and you'll be driving a mostly front wheel drive, somewhat rear driving machine. Come into a tight downhill turn and provided you were on a straightaway prior (no slipping to lock up the diff), you have a center diff, if you just made a turn or were spining a front wheel and it's locked already then the car is going to act like it's in 4WD. Good on gravel, not so good on pavement.
Basically VC are a cheap compromise to get AWD as opposed to Torsen or realy trick computer clutch diffs.
I'm not ruling it out, justing thinking, and knowing where they are used (not typical in rally cars) I'm not sure I want to deal with the problems.
Now! If one was to weld up the front diff then mount outboard VC's on each output spline, the torque would go to the back end first, and then to either front when it started to slip. This would give the car RWD characteristics, with nice progressive VC's up front it just might work. I guess the question here is; are those puny u-joints going to hold up to being the primary power transmitters, as now most of the torque will be headed along the rear drive shaft until it senses slip in the front end and locks up.
I won't bother blogging or anything, as again this is currently bench racing. The car's early days and its massive rod end suicide is well documented back a few pages in the rally section of this board. I had a habit of making up little poems for the thread titles like 'Beaten Bad a Bear' or 'Triumphant at Tall Pines'
I need another coffee...
Cheers
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Post by RedRooJusty on Oct 31, 2009 14:19:44 GMT -5
That is true the Rear bias adds a great deal of driver control into turns, allows you to throttle precision drifts as well. If you welded the front diff you would really only need to fabricate the VC into one of the front drive axles oopse.. (foot in mouth) you would need to fabricate both front axles to get the balance right. Interesting. Are you allowed to use steering brakes in the open class? Great 2004 Rally pics, those 4WD rooster tails are great! Those are some happy racers www.zapomnimedia.com/image.php?dir=galleries/rally/2004/TallPines&gallery=P-1&image=IMG_8045.jpgAbout the u-joints, you racers would probably know better than most as to how well they hold up. I have fount that OEM u-joints tend to lack grease fittings though. Find aftermarket u-joints with grease fittings, make greasing these joints regular maintenance between races. Heck if you were to worry, just collect up a sample of the expelled grease and check (dilute and filter) it for metal particles. This would give you real feedback toward the health of the u-joint(s). I used to do this SCCA racing my datsun (sss)411 (after dropping a drive-line in a race). I have also been considering the Honda "real-time" rear diff (element, CR-V), as it can engage in milli-seconds and can still allow front to rear diff slip. It is still passive (giving a slight momentary FWD bias), but is as close as one could get without adding an electronic "active" system. And it is very cool engineering. -just thoughts
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Post by indkid87 on Oct 31, 2009 14:40:15 GMT -5
Honda also used that type of system on the old wagovan civics. Might be a better source of parts.
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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 2, 2009 3:24:01 GMT -5
SJ, I actually spent some time in Seattle (2yrs), man I miss that place! Yes the limited slip rear won't do anything for the locked in place 4WD... and we have a welded rear diff if we ever need it(have never used it, but may if we run a winter rally this year). Thanks, yes Seattle is a wonderful place. Mild weather, low crime for a metropolis, kinky tastes in cars and some of the best food in the country. I like how your mind works on this issue of the locked front/rear.
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Deleted
Deleted Member
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Post by Deleted on Nov 2, 2009 12:20:49 GMT -5
I have also been considering the Honda "real-time" rear diff (element, CR-V), as it can engage in milli-seconds and can still allow front to rear diff slip. It is still passive (giving a slight momentary FWD bias), but is as close as one could get without adding an electronic "active" system. And it is very cool engineering. -just thoughts This is very similar to how the Haldex system worked on my 2004 Volkswagen R32. It uses a hydro-electric clutch to engage the rear drive. There is no center diff and when the rear wheels are driven they see 50% of the engine's torque with any slip front/rear being a product of the clutch mechanism that makes up the rear diff/Haldex unit. Getting your hands on one of those would be pretty cool as I believe it just used an electric signal to actuate it, and hydraulic pressure to engage the rear wheels within 1/3 of a slip of the front wheels (detected by the ABS system as a differential of speed front to rear). Do some searches on the Haldex system - there are some cool motion pics of how it works as well as some great cutaways out there for people like me who like to peer into mechanical devices... This is also the heart of SAAB's "X-Drive" system and some Volvo and Audi AWD cars (though most Audis use a mechanical 3diff system).
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Post by onsk8 on Nov 2, 2009 13:53:36 GMT -5
Never looked into the haldex system but would it beconsidered an active diff? the only active diff allowed through CARS rules is the center diff. Also the haldex seems like it would act like a fwd diving into corners but extra traction with 4wd on exit. Less fun and sideways but probably quicker. does this system like left foot braking?
REd roo what is steering brakes?
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Post by onsk8 on Nov 2, 2009 13:55:23 GMT -5
I forgot to add. Most audi rally cars lock their centers and rears aparently it makes the car extreamly predictable. I have yet to experiment as i am on jack stands but will let you know how i feel at another time.
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Post by RedRooJusty on Nov 2, 2009 15:13:53 GMT -5
**madmatt** the more I think about your mod suggestion (rear bias), the more I like it. **wombatsauce** I believe you are talking about the Haldex Gen1, 2, or 3 LimitedSlipCoupling (info: www.haldex.com/en/North-America/Applications-Products/Product-categories/AWD/Previous-Generations--Development/ ) which would be a great canidate for the rear drive-line mod allowing front-to-rear diff slip. I can't find one of these units that is passive or that isn't HUGE. **onsk8** the reason I didn't really expand on the steering brakes before is that in 4wd some sort of front-to-rear slip or open rear-diff would be critical to doing it. I ran twin-stick analogue steering brakes circuit racing my ol' 1969 bug (example: www2.cip1.com/ProductDetails.asp?ProductCode=C13%2D16%2D2278 ), it allowed me to control under-steer in that car all while WOT out of turns, this was a slight power leech though (using the brakes "by wheel" to control the bias of power). -just thoughts
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Post by streetruler on Nov 2, 2009 22:27:01 GMT -5
have you considered just running a spooled diff if you are going to be running rallycross? a viscus is good on the street for hamfisted jackasses but not so great for any type of racing other than bench racing at some bar if i were going to do this i would go with the r200 snub nose LSD from the older nissan 200sx turbos and the 300zx. you can identify them by the fins on the diff cover. its ruomerd that subaru shared this diff with nissan so there might be some luck there. they are indestructable and relatively cheep
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Post by ultima on Nov 3, 2009 12:52:58 GMT -5
I want some pics
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tbagg
little AK monster
Posts: 200
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Post by tbagg on Nov 3, 2009 23:54:19 GMT -5
I want some pics meeee toooo -T
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Post by eporter123 on Nov 4, 2009 4:29:14 GMT -5
On the VC issue, the old VW Syncro Vanagons had a viscous coupling. Most enthusiasts replace with a manual decoupler. www.gowesty.com/library_article.php?id=627Obviously not the part you need, but a cool idea nonetheless.
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Post by RedRooJusty on Nov 4, 2009 12:16:15 GMT -5
**streetruler** the welded (or spooled) diff is proven to give an advantage on dirt / sand / mud, **madmatt** has made mention of having a welded rear ready to go but is running pavement (open rear diff) more. -great suggestion.
**eporter123** did you notice the third paragraph mentions a solid coupling (and or worn VC's acting solid) doing damage to the syncro-front, then last paragraphs of that article mention service techs putting the either a "new" VC back into the syncro-front, or a solid coupling, but then go on saying that only stand behind a solid coupling??? kinda confusing... maybe I am not reading this right..
---and this brings me back to why I was researching VC's / LSD / auto Coupling diffs in the first place, --> to not have to worry about what surface I am driving (dirt/snow/wet/dry) when the 4wd is engaged. The realtime rear diff is just hype, I got to go play in the mud last weekend with a friend who brought his cr-v. Man my justy drifted circles around the honda cr-v. Literally!! In the cr-v I noticed a definite 1-2 front rotations before the rear wheels caught up. This made the cr-v very unstable while shifting its power bias. I have now dropped the "real-time" rear diff idea, as this systems seems to be made for commuter driving on paved roads.
I have a been looking into the r160 LSD that **stacks** mentioned, I now wonder if any Limited-Slip-core could be fitted into the front "open" diff? The thought is running a LSD both front and rear could provide just enough combined mechanical give to not damage the front axles (or just click-click-click to remind me if I stupidly forget to dis-engage the 4wd) and better all around traction. What I am now warming up to is: 1. The original system is 50/50 the front-to-rear lock is unavoidable without some sort of mid-diff. 2. Any rear drive line VC would just give me an unwanted FWD bias essentially.
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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 15:01:08 GMT -5
The original system is 50/50 the front-to-rear lock is unavoidable without some sort of mid-diff Bingo
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Post by madmatt on Nov 4, 2009 17:36:56 GMT -5
Yep... It's funny, no matter how much thought and effort you put into things, the engineers seem to have it sorted when they want to. AWD and locking diffs and such are complicated. The differences between active and passive locking are such that it's pretty hard to modify things without either completely re-engineering the thing to the point of 'might as well just buy an audi...' Somehow I think the possiblity of running two vicous or clutch pack couplings on EACH front axle might work, but if it did, why would that not be the standard way of doing things? This seems to have become a revitalized differential thread, any body have any cam specs?? He he pics; remember these are old... sort of 'glory days' for me right now.
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