SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
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Post by SeattleJusty on Jul 13, 2009 1:02:55 GMT -5
Woah, you have a factory 4X4 with unequal-length axles???
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Post by jeremydde on Jul 13, 2009 1:37:03 GMT -5
Woah, you have a factory 4X4 with unequal-length axles??? Sorry, I was mistaken they are the same length axles. I could see that in a previous photo. Jeremy
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Post by jeremydde on Jul 14, 2009 9:28:10 GMT -5
Is there any way to identify a 4wd transmission? Jeremy 88 4wd's have a 5.200 final drive Gen II 4wd have 5.285 final drive ratio -Near 1% difference, besides, the gen II gearbox is presumed to have bigger teeth/tougher ring gear than it's predecessor. -88 4wd has .631 5th gear vs all other justys @ .675(due to big ring size!) -88's have screw in type gearbox dipsticks, Gen II's are a pesky push in type -2wd or fwd offer much lower final or ring gear ratios @ 4.437 & 4.800, Gen I & Gen II respectively. If your speedo shows 80-82km@3000 in 5th then I'm afraid you have the 5.285, .675 gen II type. Good news is that there are hard to find improvements!! Any big type power upgrades is plagued with compromises, stacks Note: these gear ratios are based on a '93 owners manual and a single page of SJ's 88 service manual. If other owners find different ratios, please report. I have the screw-in dipstick so I assume that means I have an 88 transmission. Jeremy
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Post by jeremydde on Jul 14, 2009 19:14:52 GMT -5
I'll do some calculations on the highway and figure it out. I'll check the rpm at 100km/h, and adjust for tire size, then calculate it.
Jeremy
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Deleted
Deleted Member
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Post by Deleted on Jul 15, 2009 12:04:51 GMT -5
Jeremy - this is some really nice work and makes me fired up even more to get going on some welding classes. I have a '68 Mini Cooper that needs some welding here and there.
This also reminds me that I have a spare '91 4x4 5spd gearbox I need to sell at some point (along with a spare LH fender and a grille from the same years).
Top notch work, your welds are gorgeous.
Cheers,
-Jacob
"Driving a Justy is like driving a Legacy after getting out of a classic Mini Cooper."
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Post by ddddyyyy on Jul 22, 2009 22:33:20 GMT -5
I agree with jeremydde
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Danimal
Getting my two Justys back together after a Justy hiatus.
Posts: 589
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Post by Danimal on Jul 23, 2009 22:33:13 GMT -5
Classic! Sweet second post! Show us some pictures of your spam in the "Members' Justys" section.
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Post by jeremydde on Jul 30, 2009 3:57:32 GMT -5
So I have finished mounting the trigger wheel, and Ford VR sensor. This will now allow me to run individual coils, and sequential injection on the megasquirt. Even though I haven't quite finished with the megasquirt hardware mods for sequential injection, the change from the 3 toothed distributor wheel to the 36-1 has improved throttle response noticeably. Jeremy
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Post by badshah on Jul 31, 2009 11:44:56 GMT -5
Can it be that the problem with using the distributor as a sensor was because of the rubber belt flex. Something along this line is discussed here www.gtr.co.uk/forum/52458-rb30-engine-conversion-lots-pics-15.html Is it possible to use the Justy flywheel teeth as trigger? It may simplify things a bit. Actually once in uni I did build a SPFI system for my Justy by using a Daewoo Racer throttle body and used the distributor as the trigger. Did not work well Looking at your project my hands are just itching for redoing my own. Great project by the way.
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Post by jeremydde on Jul 31, 2009 14:39:19 GMT -5
Can it be that the problem with using the distributor as a sensor was because of the rubber belt flex. Something along this line is discussed here www.gtr.co.uk/forum/52458-rb30-engine-conversion-lots-pics-15.html Is it possible to use the Justy flywheel teeth as trigger? It may simplify things a bit. Actually once in uni I did build a SPFI system for my Justy by using a Daewoo Racer throttle body and used the distributor as the trigger. Did not work well Looking at your project my hands are just itching for redoing my own. Great project by the way. Rubber belt flex is definately a problem, but it seems it was a lack of resolution more than anything. Many people muse about using the flywheel as a trigger instead of a crank mounted wheel. The problem with that is that there is no missing tooth on a flywheel. The missing tooth is there to tell the computer when the crank is at TDC. Now the computer could be programmed to accept a non-missing tooth wheel on the crank so that the flywheel could be used, but then the next problem is tooth density. There are so many teeth on the flywheel that it makes it difficult to get a proper waveform at high rpm. Finally, the flywheel teeth are prone to wear which will change the gap between the VR sensor eventually causing sync problems. Jeremy
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Post by badshah on Jul 31, 2009 21:14:29 GMT -5
Nicely explained. Now be ready to make a trigger wheel for me with the sensor bracket ;D One more thing, when using the distributor we are sure of when to fire the injector, just before the intake valve opens, but when we are using the crank how do we do that. The missing tooth can tell TDC of #1 piston, but how do we determine which stroke it is?
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Post by jeremydde on Jul 31, 2009 22:43:18 GMT -5
Nicely explained. Now be ready to make a trigger wheel for me with the sensor bracket ;D One more thing, when using the distributor we are sure of when to fire the injector, just before the intake valve opens, but when we are using the crank how do we do that. The missing tooth can tell TDC of #1 piston, but how do we determine which stroke it is? We don't, thats why you could only run in batch fire with a 3 cyl (alternating with a 4 cyl). If the computer knows the number of teeth on the trigger (which it does) then simple math can allow the engine to run with basic batch injection. I am using the single tooth inside the distributor as well so that the MS knows where in the cycle that the engine is at all times. I finished converting to sequential injection last night, and it made a world of difference in idle quality, throttle response and driveability. Jeremy
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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 Jul 31, 2009 22:51:59 GMT -5
I finished converting to sequential injection last night, and it made a world of difference in idle quality, throttle response and driveability. Jeremy Most impressive
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Post by jeremydde on Aug 1, 2009 0:53:58 GMT -5
I finished converting to sequential injection last night, and it made a world of difference in idle quality, throttle response and driveability. Jeremy Most impressive The conversion? It's really just a bunch more soldering after the trigger wheel was installed. Jeremy
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Post by nolicense on Aug 28, 2009 20:30:00 GMT -5
this is probably irrelevant now, but the vj11 and vf11 have different mounting. the vj11 was made specifically for the mazda 626gt, mx6gt and ford probe gt and is very different flange from the vf series rhb5's . Have you rebuilt the vj11? they have a tendency to blow up if they sit for too long. also are you ever going to run it to its max 15-16psi? or just keep it for low boost? if its run near its max psi it has a much better flash spool compared to the 5-7psi gradual climb. another thing the mazda stock 02 housing on the hotside of the turbo is quite a bottleneck. but man, awesome job on the justy, truly good work there
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Post by jeremydde on Aug 28, 2009 20:42:24 GMT -5
this is probably irrelevant now, but the vj11 and vf11 have different mounting. the vj11 was made specifically for the mazda 626gt, mx6gt and ford probe gt and is very different flange from the vf series rhb5's . Have you rebuilt the vj11? they have a tendency to blow up if they sit for too long. also are you ever going to run it to its max 15-16psi? or just keep it for low boost? if its run near its max psi it has a much better flash spool compared to the 5-7psi gradual climb. another thing the mazda stock 02 housing on the hotside of the turbo is quite a bottleneck. but man, awesome job on the justy, truly good work there I have never had this turbo rebuilt. It has very little shaft play, and doesn't leak oil past any of the seals. I will up the boost to around 10psi, but not much higher. The factory pistons become a limiting factor at that point. It already feels like I doubled the power on this engine. I don't feel the need to push it to it's limits. The mazda hotside is a bottleneck on the engine, but it has been suggested that the limit of the 4wd transmission is around 150hp. Porting the housing, or fabricating a new one will make more power, but I don't want to get carried away. I don't want to make so much power that the driveline begins to suffer either. Jeremy
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Post by jeremydde on Aug 31, 2009 14:05:09 GMT -5
I will up the boost to around 10psi, but not much higher. The factory pistons become a limiting factor at that point. Can you expand on this? Do you think a stock piston would be first to fail if boost where too high? Is the piston strength the weak point of a stock, turbo-ed block? What if the same cast aluminum piston was used in a lower compression engine? Could one then get away without inter coolers, high octane and such at the expense of low end performance? stacks Factory pistons are the weakpoint in most factory engines if you turbocharge them. The pistons usually break before you bend a rod, unless you starve your engine of oil. Also, cast aluminum pistons aren't forgiving like a billet forged piston is. You get any detonation and you'll break the cast piston immediately. The forged piston will survive for awhile. You could run a lower compression piston without intercoolers and proper fuel, but why would you if you already spent the time building the motor properly? Cool air improves the entire powerband. It's easy enough to plumb in an intercooler. Jeremy
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Post by jeremydde on Sept 2, 2009 4:05:00 GMT -5
You could run a lower compression piston without intercoolers and proper fuel, but why would you if you already spent the time building the motor properly? I get the pleasure of being hypothetical while you progress in a practical reality. It seems the stock 9.1:1 compression ratio is pushing the limit for turbo. I'm just wondering what advantages we might get if we lowered compression? I still don't really understand why low compression ratio is better if you're gonna squeeze it to high hell anyways? Same power with smaller displacement? Here's a quick read on adding turbos, regarding compression ratio. www.torquecars.com/tuning/adding-turbo.phpstacks When you compress a gas heat is produced. The higher the compression, the greater the heat. As the combustion chamber gets hotter, this increases the chance of detonation. Intercoolers help to counteract detonation. If you lower your compression ratio, then you lower the heat that is a byproduct of compression. Since there is less heat within the combustion chamber, more air/fuel can be forced in without worrying about detonation. If you have the ability to force more air/fuel in for more power without the need to compress the mixture as much, then you can make more power reliably. I hope these cliff notes help you to understand. Jeremy
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Post by jeremydde on Sept 6, 2009 1:16:20 GMT -5
Well, my turbo-megasquirt-powered Justy passed aircare today with ease, and is emissions legal. Jeremy
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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 Sept 6, 2009 3:50:53 GMT -5
I guess your crankcase ventilation isn't too harmful to the environment after all then.
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