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#31
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I dunno, it'd seem pretty stupid that Subaru engineers would design such an incredible engine without the ability to mate it up to a manual tranny. It's a sporty engine. Obviously they must have thought the SVX was going to be a success, and perhaps use the same engine in another car.
In fact, this is the ONLY car I can think of that has a completley unique engine, excluding exotics and whatnot. Weird. - Rob |
#32
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yes you think its an incredible engine, but it has a few weak points. yes your engine has 146k, if let alone on stock eg33, you can get more years to come on the eg33 that 146k, but its putting extra load, cylinder pressure. eg33 is not and incredible engine nor did subaru design it at there top pay. few step witheld this engine to only be alttile better. its just how you learn what goes wrong when you put it to the test, and inspect how did that treatment you gave it, punished it, and from there you know what has to be done to correct it. aleast you can agree with me on that chicane
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white leathers, h.i.d, ecutune S/C stage 4, 14 inch 2piece rotors big brake kit., , msd ignition, c/f dash kit, front spoiler,carbon fiber jdm rearc wing,19 inch rims, nos, , aem fuel regulater, koni-gc package, ported cylinder heads, supercharger cams,solid buck and shims,wrx sti intake valve and exhaust valves,& valve springs, gas analizer,water injection, exhaust temp gauge, idiglo gauges, shift kit, , remote start, all automatic windows,2.5 inch true dual exhaust system with crossover, and 2 borla stainless steal muffler,air filter velocity air stack 3inch to 6 for air filtre, group n mounts, momo steering wheel, dyno will happan soon |
#33
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The chart shows the harmonics very well. I also checked out the NASIOC site, the reports on the timing disturbance, shows that even the short crank in the 4s will suffer from harmonic distortion, without the damper. What is happening is the toothed wheel on the nose of the crank, instead of just passing the pickup in one pass, it is actually passing, moving back with the crank wind up and passing again, to producing repetative signals. This shows the way the crankshaft will resonate without the harmonic damper. If you consider that the SVX crank is 50% longer than the 4s, harmonic distortion will be a real problem, with out the damper. As I have said before designing anything in an engine is a compromise. Make the crankshaft strong enough so that the fundamental resonance is not in the useful speed range and the motor would be too long and heavy. The SVX crank is as short as it can be, to keep the overall length short and to minimise the offset in the opposing cylinders so that the secondary out of balance won't be too large. Have a look at the cutaway pix in ARDUBS locker, fully machined, a lovely piece of work, but also very slim on the webs. To design a crank like this, the designer has to use the damper to to hold the harmonics in check, If not the crank will start to crack at the point that the two waves meet. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#34
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I've been watching this with interest and looked up this..
http://home.hiwaay.net/~langford/cor...gine_assy.html This shows the corvair motor only having 4 bearing surfaces as compared to the 7 that the EG33 has. There must be some difference in harmonics because of that. Mostly due to the fact that there is less distance between the bearings for the crank to flex?!?!
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cbx-man '92 LSL Liquid Silver / Automatic Level-10 valve body mod / remote filter '92 LSL Pearl White / 5 spd. IndigoSpeed 11# flywheel / ACPT Carbon fiber drive shaft '80 Honda CBX in-line 24 valve 6 cylinder |
#35
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Mychailo :: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ :: 1995 Laguna Blue SVX L AWD 5MT (sold) Visit my locker SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads. |
#36
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Crankshaft harmonics.
The crankshaft harmonics that we talk about has nothing to do with the primary or secondary balance of the engine.
The SVX engine has no primary out of balance, each piston and rod is balanced by the opposing piston and rod. There is a secondary out of balance that is generated by the opposing cylinders not being on the same center line, this is so the two big ends can lie side by side on two different crank pins. This secondary out of balance is felt in an opposed twin as a rocking couple, the more cylinders there are, the less the rocking couple is felt. Thus the 6 cylinder is smoother than the 4 cylinder. The crankshaft harmonics are only related to the twisting of the crankshaft due to its length. The design of the motor has the drive taken off one end, other designs take the drive off the center of the crank to prevent the harmonic distortion. To try to describe what this distortion is and how it comes about is difficult. If we just consider the crankshaft with no 1 cylinder only. When the cylinder fires it accelerates the front of the crank, the flywheel and the drive train can not accelerate as quickly due to the inertia, so the shaft winds up till the flywheel accelerates up to speed. By this time the cylinder has stopped pushing and now requires driving by the flywheel, so the crank winds up the other way while the flywheel drives the no 1 cylinder around to the next power stroke. So we have a wind up as the piston drives the flywheel and an unwind as the flywheel drives the piston. If this unwind arrives back at the piston, in time for the piston to wind it up again. If we now double the speed of the engine and follow the wave action, the cylinder winds up the crank accelerates the flywheel, the flywheel unwinds the crank to drive the no1 cylinder, But before the unwind wave arrives back at the cylinder, the piston has fired again, to wind up the crank again. So we have an unwind wave coming from the flywheel and a wind up wave coming from the piston. Where these two waves meet there is maximum rotational displacement of the crank. One side is twisted fully clockwise, the other side is twisted fully anti-clockwise. This is then call a critical resonate frequency. Every time the speed of the motor is doubled or halved, we develop another critical frequency. So the designers have to ensure that the end design does not have the engine operating for long periods of time at any of these critical frequencies. If it works out that the cruse speed corresponds with a critical, then a harmonic damper is tuned to move the critical at least 10% away from the speed that the engine is to run at. The damper uses a weighted rim, rubber mounted to the hub. The weight always moves in anti-phase to the harmonic and the rubber damps some of the energy. As I have said the SVX crank is a great piece of design work but. The harmonic hamper is an integral part of it's design. Replacing it with an aluminium light weight pulley, is to remove the safe guards that the designers have provided and you must accept the fact, that the crank may break at some future date. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. Last edited by oab_au; 05-18-2003 at 09:31 PM. |
#37
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Harvey your in depth knowledge of the subject is obvious and appreciated but you have inadvertently left out describing an important factor.
Engine designers use the load available in respect of driven accessories as a means of damping torsional vibrations, particularly in the lower frequencies, as is exhibited in many engine designs, even those of vintage character. Electrical machines provide an excellent facility as do rotary pumps and fans. What is more any accessory driven by means of a flexible belt incorporates an additional damping medium. The pulley in question drives a load and this load applied via the cushion incorporated in the pulley has greater effect than the inertia created by the weight of the pulley. However I agree with you that doing away with the pulley and integral damper on the basis of restricting inertia, in respect of a stock engine, is completely futile. The mass involved is quite insignificant. The gullible will always present a lucrative market !!!! Rergards, Trevor.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#38
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I agree with it being a pointless mod, when you consider the inertia removed, is very small when you add the flywheel, transmission, drive shafts, differentials, half shafts hubs, disks, wheels and tyres. Then there is the 3500 car mass that has to be accelerated. A few pounds on a 5 " diameter is about 2 tenths of " Sweet Fxxx All" Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#39
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Hi Harvey,
I think we had BOTH best stay out of MOD Mania. By expressing fact we may wind up in very hot water !!! If the need arises let us stick together in the ANZAC spirit and then we can NEVER be got at. Dare I say it but I will, " some of the stuff posted here is bloody stupid. " I may now need your back up and covering fire !!! Take aim with your pistol. ( another thing we should OT on ). Trevor, P.S. I wonder if anyone has tried removing their wheel nuts. ( I think I should say lug nuts as they still must have split rims and not wheels up top ! ) Lots of mass there for sure. Why not remove the rims and run on the spokes for a truly invigerating ride !!
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! Last edited by Trevor; 05-21-2003 at 07:51 PM. |
#40
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<<<However I agree with you that doing away with the pulley and integral damper on the basis of restricting inertia, in respect of a stock engine, is completely futile. The mass involved is quite insignificant.
The gullible will always present a lucrative market !!!! Rergards, Trevor>>> Yes, but with a 5 spd and a light flywheel, this made a noticeable difference on my car. This is not an opinion or theory, this is spoken from experience. The notion that I may have compromised the longevity of my motor by adding this pulley is valid. But very few go fast goodies don't carry that baggage. Has anyone lost a motor by putting one on? I don't believe the hype about anything. I want to see for myself. That's why I have tried seven different custom exhaust systems. I have built my own cold air intake, as many have. I run a very aggressive shot of dry nitrous, even though everyone said the injectors couldn't hack it. My reward is that I can go faster than pretty much any other SVX. I am originally from DC so I learned at an early age not to believe everything I hear. So excuse me if I don't consider myself gullible.
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92 Ebony - Level 10/n2o REAR-ENDED 92 Teal - painted yellow/4.11 5spd/n2o SOLD 92 Claret - 4.44 SOLD 94 Barcelona - FWD SOLD 92 Ebony - 3.90 SOLD 94 Laguna ROLLING w/4.44s/Ecutune ECU +TCU/STI springs/Infiniti M45 rims |
#41
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Please advise how you confirmed and measured " the noticeable difference ".
Scientific proof is required not advice as to what you perceive as has occured after becoming happy as a result adding a talking piece. No personal offence is in any way intended here. You have been able to address me in person. I would like you to afford me the same courtesy. Trevor
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#42
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The noticeable difference is real. I did not measure a before and after with just that mod. I lumped it together with the intake, exhaust and 5 spd mods(w/G-tech pro). For that, I apologize. I just don't have enough time to do everything I would like to. The total difference came out to be a second and a quarter quicker to 60 mph. To be honest, I didn't expect to feel much of anything when I put it on. But I was nicely surprised. It just revs more freely now. Otherwise it would be for sale somewhere. I have tried a couple of things that I had high hopes for that I didn't like. The true dual exhaust for example. After two weeks of designing, fitting and welding, that lasted one day on my car. Fortunately I was able to rework it into something I like. But anyway, I could put the stock pulley back on and compare the times. But the times aren't nearly as consistent as with the AT due to the launch factor and we are probably only talking about .2 seconds at the most. Maybe if I did like five of each, it might play out. I haven't even done five hard launches yet with the 5 spd. Nor have I filled the tank yet. No $$$ right now. Do you think that might be 'scientific' enough? That's about the best I can do.
Stephen PS. I have a tremendous amount of respect for you and Harvey and read all your posts like a student in class.
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92 Ebony - Level 10/n2o REAR-ENDED 92 Teal - painted yellow/4.11 5spd/n2o SOLD 92 Claret - 4.44 SOLD 94 Barcelona - FWD SOLD 92 Ebony - 3.90 SOLD 94 Laguna ROLLING w/4.44s/Ecutune ECU +TCU/STI springs/Infiniti M45 rims |
#43
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Stephen thank you very much for your excellent reply,
I think you have disclosed the problem so often present in these issues. You did not test each modification you have made individually. You can not be sure which contributed and which did not. One in fact may have proved detrimental. I do not think we should expand on the issue. It is a basic rule that when tuning or making any alteration in an effort to improve something two or more operations should not be done at once prior to testing. The same criteria stands good in respect of fault finding. Special regards, Trevor. *<)
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! Last edited by Trevor; 05-22-2003 at 12:18 AM. |
#44
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For clarification, I did each mod separately and gave it the 'seat of the pants' testing individually of the other mods. Although I didn't run the times separately. I actually don't like pushing the car too much. But I have modded enough cars to get a feel for the before and after difference. And this one was more than I expected. It had about the same effect as putting a light flywheel on my RX-7. Probably wouldn't make as much of a difference on the AT though.
Stephen For the record: intake mod- no discernable difference exhaust mods- noticeable difference light crank pulley- noticeable difference 5 spd- KICKS ASS! Nitrous- HAHAHAHAHA!
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92 Ebony - Level 10/n2o REAR-ENDED 92 Teal - painted yellow/4.11 5spd/n2o SOLD 92 Claret - 4.44 SOLD 94 Barcelona - FWD SOLD 92 Ebony - 3.90 SOLD 94 Laguna ROLLING w/4.44s/Ecutune ECU +TCU/STI springs/Infiniti M45 rims |
#45
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Accepting that argument is futile, all I will say is that you have illustrated quite remarkable powers of perception. As long as you are happy stay with it.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
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