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#46
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Re: Re: Interesting EG33 output comparison...
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Like drivemusicnow and mbtoloczko were trying to explain, you really missed the point of my post. The SVX/EG33 was designed back in the late 80's by Subaru and released in '91 to the Japanese market initially... We're talking about technology that's over 15 years old. Comparing the EG33 to engines in sports cars/sedans available today would not be a fair comparison as 15 years of technology & engineering advances have taken place. My goal was to have as close of a true apples-to-apples comparison as possible. The SVX was often pitted against these very same cars in magazine reviews, and it was in the same price range of all the cars I've compared it to. BTW, 230hp out of 3.3L is still respectable these days. Lexus gets 215hp in their 3.0L IS300, and BMW gets 225hp in their 3.0L 330i... -Chike
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"Wise men talk because they have something to say; fools, because they have to say something." - Plato 2013 Cosmic Blue 5spd Evo X GSR 2006 Galaxy Gray 6MT RX-8 (sold) 2006 Steel Gray WRX TR (sold) 1996 Brilliant Red SVX L (sold) |
#47
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Re: What is there to compare?
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So how could we raise peak torque (thereby raising hp) and raise the redline of the engine... and which would give the best performance for a street driven application? Obviously the general consensus on these boards is that stock tuning is ultimate... (with the chip it flattens and increases torque curve, but tahts just doing something more tightly regulated that what could be done when the car was made) How could you keep that bottom end, IRIS tuned torque, while raising the "other"/"real" peak torque in rpms
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Greg 97 Red SVX LSi clean 96 Black SVX LSi beater 90 Red Eclipse GSX track ho 99 Ford F250 work horse My Locker |
#48
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Re: Re: What is there to compare?
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-B
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Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker |
#49
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What to do?
While the gear box is going to change at the same rpms, regardless of the engine rpms, there is nothing to be gained by raising the rpm, that the peak torque is produced at. Unless it is fitted with a manual box, that could run into the higher rpms.
Increasing the valve lift is really the only thing that will increase the torque, and the acceleration, without resorting to pumping more air in. The valve sizes are big enough for the cylinder size, the ports are fine as they are, and the inlet and exhaust tracts are well suited to the overall design. I think if you want to increase the preformance, you will have to forget the interferance design, and use bigger valve lift. Breaking a timing belt, though not unknown, is not something that would worry someone, that wants to get results. I would just replace it at a half distance. Most high preformance engines are interferance, just no way around it. If you are that worried about it, you should stay standard. The lift now is 7mm inlet, 8mm exhaust, I think the difference in the lifts, is to do with the noninterferance bit. The inlet valve is 37mm, the exhaust 36mm. This looks like the bigger inlet would hit if given the same lift as the exhaust. I think the ideal cam to use, would have the same duration, with the inlet cam lift increased to 9mm. This would keep the cost down to just two cam regrinds, instead of four. The results would be more torque, everywhere, an increase in HP, and the Inerta and Resonate tuning would work the same, as he duration remains the same. The cam grinding can be done by reducing the base circle, or increasing the lobe height. If there is no lobe clearence problems, the latter would be the go. If there is a problem with the taller lobe hitting the sides of the follower well, reducing the base circle and fitting a 2mm shim under the follower would have to be done. Nothing ventured, nothing gained. 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. |
#50
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Hey Harvey, I'm curious about thoughts on something related to what you wrote above. I've done quite a few calculations on predicting HP of the SVX motor based on engine size, air temperature, a/f ratio, and in order to get an answer of 230 HP at 5400 rpm, its always necessary to use a volumetric efficiency of 100% or more. So, I'm wondering how much there would be to gain by increasing valve lift. I think it would be interesting to try, but I just wonder how much there will be to gain.
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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. |
#51
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What about making it an interference engine...
increase the intake lift to 8mm... 9mmif possible AND increase the compression ratio to 11, maybe 12:1... yeah, you'd be screwed if you broke the timing belt, but would the higher compression ratio be enough to bump out power output "significantly"? Doming the pistons would obviously give you even less clearence... but how would that affect overall torque output
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Greg 97 Red SVX LSi clean 96 Black SVX LSi beater 90 Red Eclipse GSX track ho 99 Ford F250 work horse My Locker |
#52
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Re: What to do?
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Like Mychailo, I'm also interested in knowing the approx gains in hp & tq that might be returned if inlet lift was increased from 7mm to 9mm? Having two cams ground instead of four would definitely save big $$$ as most shops in my area charge at least $100 per cam... -Chike
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"Wise men talk because they have something to say; fools, because they have to say something." - Plato 2013 Cosmic Blue 5spd Evo X GSR 2006 Galaxy Gray 6MT RX-8 (sold) 2006 Steel Gray WRX TR (sold) 1996 Brilliant Red SVX L (sold) |
#53
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100% plus Volumetric Efficency.
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This is why I keep saying to keep the front end of the exhaust system and resonator, the same. There is a lot of power produced by the standard system. Without the resonate tuning, we would still be in the efficency zone of a pushrod V8. Look at the VE that two stroke engines have achived, to produce 80+ HP from 250cc. only possible with the effect, of the sound wave pressures, that resonate systems can produce. To site another 500cc cylinder, of the same make-up as ours. The Ducati 996 uses lifts of 9mm inlet 8mm exhaust, produces torque at 8000, HP at 8500. The Sport Production version increases the inlet lift to 10mm, the torque moves to 7000 and the HP at 9500. The torque is produced at a lower rpm, but it maintains the VE over a wider rpm range, to produce the HP at the higher rpms. This shows the way increasing the lift will raise the max. torque and spread the curve. So there is no risk that increasing the lift will increase the VE of our engine. 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. |
#54
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I would prefer the lower 10:1 that gives a bit of leway if it suffers a lean mixture or advance problems, without self destructing. 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. |
#55
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Re: Re: What to do?
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All I can say is you won't need a G-tec to show the increase. It will be most obvious. 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; 12-04-2004 at 04:20 PM. |
#56
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#57
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Re: Re: Re: What to do?
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Will also need to toss in some suspension and braking mods as well. -Chike
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"Wise men talk because they have something to say; fools, because they have to say something." - Plato 2013 Cosmic Blue 5spd Evo X GSR 2006 Galaxy Gray 6MT RX-8 (sold) 2006 Steel Gray WRX TR (sold) 1996 Brilliant Red SVX L (sold) Last edited by Chiketkd; 12-04-2004 at 07:58 PM. |
#58
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Re: 100% plus Volumetric Efficency.
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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. |
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