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Post by Deleted on May 3, 2014 10:24:27 GMT -5
A note on the scavenging, this is the reason I made a short header and used the angles to my advantage. My outside ports come in at 45deg angles to the center tube, I envisioned a venturi effect. No idea if this actually happens or not but that was my theory.I think that is all I was trying to say, with much less words. I as well have had at least four different ideas for a header design for the Justy. I would like to build a couple and then rent a dyno here locally for a few hours to swap things around and test. I have ideas for things that would potentially improve torque, or high RPM, or to smooth out the pulses from the 3-cylinder. Until I have a way to test it, the simplest design makes the most sense. Can't wait to get a garage and a welder. The phenomenon you're describing with removing the muffler does make sense. And here's how I see it. The idea of having back pressure in the exhaust is to help heat it up. Hot air flows much better than cold air. If you have a straight pipe exhaust, it is not getting up to temperature so the engine is pushing all this super hot air in to a (relatively) cold exhaust, and you lose the scavenging effect as the flow consistency is affected. Terry Maybe... I think it has more to do with exhaust velocity and how it comes into play with the engine's performance. It sounds like the Justy is a perfect application for a dual-stage, vacuum-actuated bypass like my last Volkswagen had. That way you could have the low RPM torque (helped by the slightly more restrictive exhaust which keeps velocities up) and then when it hits, say, 4krpm, a flapper door opens and the muffler is bypassed. I actually think this is doable. I have access to a dynomometer and a friend who welds. It would take a lot of time to build the pieces but if I can do it, I will. Until then, I would like to create a simple, but effective, tube-header to replace my manifold. I am not looking to tune my car, but rather, to create a manifold that "I like better" that is of a simpler design that frees the car of the need for that strange and expensive front catalyst. Basically this will be a 3-1 "shorty" feeding into a downtube. It would be so awesome to be able to build say 4 or so different designs, and then run the car on the dyno and SEE how they affected the engine's performance.
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Post by Armageddous on May 3, 2014 23:38:15 GMT -5
That kind of information could be paramount for those decided how to build up their cars. 3 cylinders are uncharted for most engine builders.. It seems like when the topic comes up a huge question mark floats above their head.
Terry
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Post by madmatt on May 5, 2014 21:36:12 GMT -5
We may be dealing with a bit of a difference of opinion on what constitutes "low end"... and that may make some sense, but I have a couple other theories too. To me, on the justy, low end is anything below 3000 rpm, mid is up to 4500 or so, and top end above that. I would have "made a mistake" on stage if I dropped below 2500 rpm,, not enough torque down there to do anything worth while... So perhaps below 2500 rpm the muffler helps. However, it also makes it noisy... and we know what noise does to the butt dyno. My MGB has 40000 hp, cause it so friggin noisy, but when I floor it, i just keeps up with traffic. So take that to the other end, Wombat, I'm not saying this is what happened, but might you have not been as hard on the throttle climbing San Fran hills with no muffler? Sure as hell I don't open the throttle in town much without a decent muffler on, my neighbours would hate me even more!
Back when I first built the Justy rally monster in 2004 (before the triple carb nonsense). I did a bunch of testing with a stop watch, I don't have the data anymore, it's long been lost... but I routinely did timed 2000-6000rpm pulls in 2nd gear to test results. End result was I shaved more then a second, close to 2, opening the exhaust, doing very minor head work, and lightning the flywheel. That's real world gains.
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Post by Deleted on May 7, 2014 10:50:08 GMT -5
I forgot to mention that in 2006, when I got my 1991 4x4 Justy GL 5spd that I currently drive today, it had a stock exhaust with a "Bosal" rear muffler on it. The car was just about gutless with this muffler on it, and it ran much better without it. My "compromise" was to have a Magnaflow straight-through muffler installed, but with stock-sized piping leading to the muffler, and this has found a happy balance, in my opinion, for my uses, between no muffler and the Bosal which I feel was too restrictive. This muffler was tiny, and used a very small pipe size - could not have been much more than an inch. It was smaller than the stock piping leading to it. So from what I have found: Restrictive muffler: peppy off the line and loses steam around when it should start to have power (4krpm in my opinion) Free flowing muffler: peppy off the line, linear and good acceleration all the way up to and slightly past redline No muffler: need to leave the line at higher RPM, and engine has little power until 4krpm then screams to redline (keep in mind this is around 2.5krpm of usable power) Will lug trying to accelerate at 2.5krpm where with a free-flowing muffler it actually has useful torque down there. Just depends on if your Justy is a motorcar or a straight-line racer I guess. That muffler, removing the intake "snorkus" plus a tiny bit of timing advance and CA91 fuel is my recipe for a Justy that keeps up with today's cars, and is wicked fun on the back roads. My engine is usually between 2500 and 6500rpm and my throttle is treated like an on/off switch. Usually on. After removing the "snorkus" is when I noticed the Justy's "surge" of acceleration at 4krpm. Both of my cars did this, both EFI. If you WOT at 3500 and hold sweeping past 4k, you can hear induction growl rattle the glovebox which of course is awesome. We may be dealing with a bit of a difference of opinion on what constitutes "low end"... and that may make some sense, but I have a couple other theories too. To me, on the justy, low end is anything below 3000 rpm, mid is up to 4500 or so, and top end above that. I would have "made a mistake" on stage if I dropped below 2500 rpm,, not enough torque down there to do anything worth while... So perhaps below 2500 rpm the muffler helps. However, it also makes it noisy... and we know what noise does to the butt dyno. My MGB has 40000 hp, cause it so friggin noisy, but when I floor it, i just keeps up with traffic. So take that to the other end, Wombat, I'm not saying this is what happened, but might you have not been as hard on the throttle climbing San Fran hills with no muffler? Sure as hell I don't open the throttle in town much without a decent muffler on, my neighbours would hate me even more! Back when I first built the Justy rally monster in 2004 (before the triple carb nonsense). I did a bunch of testing with a stop watch, I don't have the data anymore, it's long been lost... but I routinely did timed 2000-6000rpm pulls in 2nd gear to test results. End result was I shaved more then a second, close to 2, opening the exhaust, doing very minor head work, and lightning the flywheel. That's real world gains. Difference of opinion? Okay sure - that must be it. You did some acceleration testing, on level ground in a straight line, and you don't have the info or remember but you are sure it backs up this theory that real-world "muffler play" can quite easily debunk. Got it. Look, I can read a book and conceptualize that air travels faster without restriction and make knowledge-free assumptions too, but that is not what I am talking about here. So you are saying that I thought the car did not have as much low-end torque without the muffler simply because I was not pressing the throttle as hard as when I had the muffler on the car? I mean, really? For the record, the Justy with an otherwise stock exhaust is just about silent even at 500rpm past redline with no muffler. You can just barely hear it over the mechanical and wind noise. At idle you can hear a slight "putt-putt-putt" and that's it. Had the car been more drivable in the way I use it (ie, not drag racing a Justy here but using it as a motorcar) I would have left it. But, due to the lack of torque below 3krpm, it required much more clutch abuse to drive it around. I have done around 50k miles in my two Justys over the past 8 or so years, and done lots and lots and lots of testing. Never really did much straight-line 0-to-X acceleration testing since that does not matter at all. Accelerating up a steep hill from 25 to 45mph though, sure. Accelerating from 40-70mph, definitely. You have got to be kidding me.. The only way you can accept my real-world experience is to conjure up that I was just doing something dumb to come to that conclusion. I think we are done here. Not sure if you even read my posts or if it matters. Best of luck with your endeavors. Cheers.
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Post by madmatt on May 7, 2014 11:29:14 GMT -5
Really? Wombatsauce? I thought we were having an interesting conversation about our "real world" endeavors... not sure where I went so wrong on you. Where did I say you were "doing something dumb" ? I simply stated that you since you didn't have data either, perhaps, just perhaps, there was testing error. I know my Justy was pretty loud with stock cat, pipe and no muffler. Loud enough that it was too loud to run without a muffler at our rallies (it measured 89db if I remember correctly, at 3500 rpm, that's pretty loud.) Where did I say I didn't have the any of info from my testing... I said the data is missing, but it was more then a second close to 2. What I don't have is all the steps we went through, repeated testing in both directions on a level road, sorry I wasn't on a dyno, but I remember the results. I think we went through about 4 different steps, as I went from stock through 1.75 exhaust with a "glasspack" to having .5mm off the head, a K&N filter (available for carbed only) and a huge chunk taken off the flywheel. Again, it was 10 yrs ago... I've moved 4 times, and lost track of a ton of stuff over the years. If you have no desire to converse about projects that are intended to increase performance of our beloved little ecno box, then fine. No problem with me. But our OP asked about building a "performance" engine (that's the title of the thread), and so since I have been working for over 10 years on this friggin thing trying to actually make more power, I thought I'd weigh in. Cheers, Oh, and I'm happy to carry on the conversation about what you have done. I find all this stuff fascinating.
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Post by indkid87 on May 8, 2014 11:06:57 GMT -5
Personally I think there's too many variables in any kind of "real world" testing. You have to take into consideration the air temperature/pressure, human error, road conditions.... To me that's too many X factors for truly viable results, especially with a carbureted car. What works well for one car/driver on any given day may not work well for someone else. Without controlled dyno data it's hard to compare any results.
Personally, I'm running a stock manifold into a gutted cat, then 2" pipe to a side exit with nothing but a glasspack. So basically there's no back pressure to speak of. With the stock motor it definitely has the kind of power you'd expect to get out of a 3 cylinder. I don't see my lack of "back pressure" costing me any time on the rallyx track.
Matt, I can see your car being louder than wombatsauce. Not having an interior makes a huge difference. When my car was straight piped weather or not I had the back seat in was the difference between the noise level being tolerable and having my ears bleed.
-Dave
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Post by Armageddous on May 8, 2014 21:20:43 GMT -5
I think the general consensus is that back pressure, and exhaust modifications are a bit of a mystery. I mean hey, I work at a custom exhaust shop and build it for a living. I know how to make a car sounds good and flow properly, but I can't say what's ideal for maximum power at what RPM. I've always just told people to watch the size of pipe you use. You can push 200HP (or something, I have a chart at work..) thru a 2.25" pipe. Stick dual 2.25 on a stock Ford 302 that has a whopping 180hp, you have enough tubing to carry 400hp, do you think it's going to feel like a balanced motor? (And yes, it will sound terrible). Also when exhaust doesn't heat up enough, it tends to rot out quickly. madmatt and wombatsauce; Pure genius, and you don't even know it. You two proved the ony thing that matters - How the car feels (or is perceived) to the driver. Terry
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Post by madmatt on May 14, 2014 21:38:46 GMT -5
madmatt and wombatsauce; Pure genius, and you don't even know it. You two proved the ony thing that matters - How the car feels (or is perceived) to the driver. Terry Thanks, I hope we can come to terms over this. I'm truly interested in results.
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Post by kcswimrac on Sept 15, 2014 12:49:50 GMT -5
Just thought I'd give an update. I found an EFI head near me, took it to the shop and had it gone through. Here are the pictures, isn't it pretty? lol Next step line boring, honing, and maybe a little shave on the block.
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Post by kcswimrac on Sept 15, 2014 16:18:32 GMT -5
Alright, also just sent the cam off to Delta cam to get a more aggressive grind on it. And the MegaSquirt V3 is on order! I'm getting there!! I have to try to beat the snow fall in Oregon so I can have some small car four wheel drive fun! Wish me luck!
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Post by kcswimrac on Sept 23, 2014 16:53:50 GMT -5
Alright, question madmatt, how did you deal with the cam timing being incorrect after the head shave?
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Post by madmatt on Sept 23, 2014 21:49:50 GMT -5
Honestly...
Didn't...
I remember I spent a couple nights looking at the cam wheel, drawing it out and seeing if clocking it would do anything.
In the end I figured 1.5mm was less then a cog, so forget it... bolt it up.
Dyno tuning is still a near dream, hopefully this fall before Pines (if we make it), and I may play with some sort of clocking there.
Did you use Delta's in house spec, or something different?
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Post by kcswimrac on Sept 23, 2014 22:23:13 GMT -5
Using Delta's in house spec, and I'm only shaving 1mm off, well actually 40 thousands off, and that only puts my cam timing off by 1.064 degrees. Thanks I'm sure it will be fine. Lol.
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Post by kcswimrac on Oct 31, 2014 13:05:16 GMT -5
Alright, I figure it's been awhile and about time for an update. I now have all the parts that I need to reassemble the engine, as of yesterday it is slowly going back together. Don't mind the painted oil pressure switch, that is being replaced. lol Although I have a question. How do you install the balance shaft and know it's aligned correctly with the crank? I couldn't find any alignment marks to reference.
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Post by Deleted on Nov 13, 2014 16:28:59 GMT -5
madmatt and wombatsauce; Pure genius, and you don't even know it. You two proved the ony thing that matters - How the car feels (or is perceived) to the driver. Terry Thanks, I hope we can come to terms over this. I'm truly interested in results. Wow it's been a while since I have come back here. I checked back a couple times but did not reply because I don't know what to say. I did not intend to cause a problem, yet I can see how I might have. I did not edit/delete my post because that would be lame I guess. I can, if that would be best. Anyway - no worries!! I have read some of the posts here and am stoked to see some interest in the Justy, new and old. Matt - your rally Justy is awesome and I want a header. I am driving my Justy today - I took the roof racks off and put the wheel covers on. "Aero mode" if you will. I also ordered another set of '95 Ford Escort wheels. My plan this time is to have them bored out to 59.2mm then coated dark silver. I have a set of Yokohama 185/55-14's picked out that I hope will work well. I am serious about the header; if there is any way to build one I will pay time+materials+fair price for this. My ultimate goal is to have one that fits under the stock shroud (for emissions passing reasons) but outputs to a normal "flanged" downpipe so I can add a catalytic converter that is easily replaceable. Then, I would like to do 1.75" pipe back to my existing muffler, to 2" out the tailpipe. I still think about a "performance build" every day and would do it if I had the extra money. I would like something that is happy spinning a little higher RPM and possibly a 500-1000rpm higher redline. A remote oil filter would be rad. I think my thermostat has died... Anyway... Howdy. Hope all is well.
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Post by madmatt on Nov 14, 2014 9:26:46 GMT -5
Wombatsauce, Great, Welcome back into the fold, please contribute. And maybe I read your comments with a harsher tone then you intended. While I'd love to build you a header, I don't feel my skills are up to producing products for the market just yet But... Holland Justy has these beautiful flanges made up... subarujusty.proboards.com/thread/2915/orange-rally-justy-returns?page=4 that is where it all begins! And that 4AGE stock header I used to build mine is apparently the "unwanted" amongst Corolla folks, as they all put bling bling stuff on (that thing came stock, can you imagine!) The tuning is getting better on mine. It now routinely lays rubber with roll on throttle in 2nd. 175/70 snows. Tall Pines Rally in 2 weeks!
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Post by Deleted on Nov 20, 2014 11:03:01 GMT -5
Wombatsauce, Great, Welcome back into the fold, please contribute. And maybe I read your comments with a harsher tone then you intended. While I'd love to build you a header, I don't feel my skills are up to producing products for the market just yet But... Holland Justy has these beautiful flanges made up... subarujusty.proboards.com/thread/2915/orange-rally-justy-returns?page=4 that is where it all begins! And that 4AGE stock header I used to build mine is apparently the "unwanted" amongst Corolla folks, as they all put bling bling stuff on (that thing came stock, can you imagine!) The tuning is getting better on mine. It now routinely lays rubber with roll on throttle in 2nd. 175/70 snows. Tall Pines Rally in 2 weeks! I probably did the same regarding the comments. Trying to be better about that. I get what you are saying about the header. I appreciate that. I just want to get something going. Had intended to get a welder and practice but life had other plans for me and I am finally back at the state where I might be able to think about maybe considering the possibility of starting to save money for a welder. That Toyota header/manifold looks almost exactly like the one I put on my old 2002 MR2 with the stock 1ZZ 1.8L engine. It had a catalytic converter that looked like that header with two "pineapple" sized cats, one for cyl 1+3, the other for 2+4. They were famous for clogging one cat and then taking the engine with it over time. I found a header on eBay that looked like that one for around $80, and then had it coated. Might be an option for me. Those flanges are beautiful! I am going to talk to my mechanic/welder friend and see if he wouldn't mind making something. My brake issue is seemingly still an issue so I will be driving the car less in the winter anyway. (brake issue: hard braking on wet roads instantly locks the RF wheel, also very low pressure to rear wheels, so far have replaced the calipers/pads+drums/shoes/wheel cylinders and M/C, next up is lines and the distribution block. Mechanic said his helper could still turn a rear wheel with a breaker bar while he was mashing the brake pedal.) That's crazy about laying rubber with a roll-on in 2nd! Awesome! Mine leaps forward and then rattles the glovebox with induction noise around 4krpm and screams up to ~500 past redline but no rubber. Now that I know how totally different our engines/exhausts/cars/usage of such car/etc is, it makes sense how different our experiences have been. I treat my throttle like an on/off switch for the most part, but rarely get to drive on dirt these days. Best of luck in the Rally. That is so awesome. Do you have in-car video? Would be fun to watch. I picked up a Blackvue dashcam for around $200 USD and it's been pretty cool to use.
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Post by kcswimrac on Feb 1, 2015 14:38:42 GMT -5
I figure it's about time for an update, the engine is fully rebuilt, shaved .060" off the head should bring me up to about a 10:1-10.5:1 compression ratio, has the in house spec grind by delta cam. The engine is back in the car, the megasquirt3 is installed with coil on plug, the majority of the wiring is worked out, still need to find a tps off of the "unicorn" bmw, for now I am trying to run it off of a Maf sensor, a wideband o2, and a MAP sensor which according to Megasquirt should work fine for estimating engine load but I still want to get a TPS for at least logging and fine tuning purposes. In the next couple of weekends I shall have a running and driving Justy again with way more power than it used to have, since the previous owner said they believed they rolled the Odometer over twice, which meant this poor thing had ~230,000 miles on it and had a smoke screen that rivaled Batmans when it started cold. And even in such a poor state it was a fun reliable adventure car that I can't complain about. Hopefully in the next couple weeks I'll be posting pictures of it out exploring Oregon with it's new found power.
P.S. I am currently modeling an equal length header setup for the Justy, I bought an exhaust flange from HollandJusty that will hopefully be here soon, when that gets here, Justine shall be getting a custom tig welded stainless exhaust!!
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Post by madmatt on Feb 2, 2015 19:58:12 GMT -5
SOOOOO MUCH AWESOME! Can't wait for results... this will be wicked. I will give one bit of warning... I'm looking for a new bottom end (again) Not sure if you read my build thread, but I fully rebuilt the bottom end, it was pretty tight, made good oil pressure to start. At tall pines this fall I tore up another #1 rod bearing. SIlly me kept driving till it blew. But the moral is,I don't think the oil pump is up to the task of sustained high RPM. Which is hard to avoid with that cam... I am headed towards dry sumping on the cheap... Will give details once I have it sorted.
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Post by kcswimrac on Feb 3, 2015 0:38:58 GMT -5
Thanks Madmatt, I saw your misfortune, Sorry it went so terrible, But I guess that's just the risk we run when we push our little 3 cylinders..
I'm thinking once I get her up and running I'm going to try (I believe it was your proposed oil solution) of basically extending the pump rotor and the housing. I ordered two new sets of oil pumps already and plan to cut the shaft off of one and TIG weld the two inner pieces together and the outer oil pump pieces together, I'll machine a spacer/sleeve to hold the extra extension. I'm thinking this should be doable since i'm in college, have access to a welding shop, and am a "teachers aid" in our machine shop. Hopefully i'll get her running soon and have a chance to try the oil pump fitment out, the only issue I see having to get around is that the extended oil pump would interfere with the alternator belt, but I figure I should be able to come up with a work around for that.
Any ideas, feel free to speak.
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