SVX Network Forums Live Chat! SVX or Subaru Links Old Lockers Photo Post How-To Documents Message Archive SVX Shop Search |
IRC users: |
#31
|
||||
|
||||
Re: Camshafts for the EG33.
Can you explain this a bit? I Googled hard/soft rev limiter and got not very consistent results. Also what you mean about the hydraulic lifters and losing compression.
__________________
'94 Laguna Blue LSi ~159k.......JDM ultra short-geared 3.900 STi Version 7 6-speed w/ Cobb shortshifter, ECUtune 244,8.1mm/256,9.1mm i/e cams, group N motor mounts, '97 grille, JDM clear corners, Momo JDM Legacy GT steering wheel, apkarian's LED tails, silver STi BBS wheels, PWR radiator, redstuff pads f/r, drilled/slotted rotors, bontragerworks rsb #18, Koni/GC 450f/375r coilovers, Megan Racing adjustable lateral links, KMac c/c plates, Stebro exhaust, ECUtune 1v5, Optima battery in the trunk where it belongs. Turbo project '97 Ebony LSi ~137k #036.......Power mode mod, JDM clear corners, BBS wheels. AUX/pocket mod Now a mod "over there" ............Photo album Last edited by icingdeath88; 07-31-2012 at 09:35 PM. |
#32
|
||||
|
||||
Re: Camshafts for the EG33.
Are lighter/stronger (titanium) retainers/keepers available for our stock valves?
Just to lighten the load.
__________________
www.svxfiles.com The first SuperCharged SVX, the first 4.44 gears, the first equal length headers, the first phenolic spacers, the first Class Glass fiberglass hood, the first with 4, 4.44s in his driveway Fiberglass Hood thread My locker 4.44 Swap link |
#33
|
|||
|
|||
Re: Camshafts for the EG33.
Quote:
Btw for my ecu hard cut is exactly that - fuel and spark completely cut off. The result is the sound of a cannon going off. Soft cut just cuts some of the cylinders and can cut either fuel or ignition or both. All depends on the ecu and it all depends on the settings you put in as it's all customisable. Last edited by bazza; 07-31-2012 at 10:27 PM. |
#34
|
||||
|
||||
Re: Camshafts for the EG33.
Quote:
Good idea! Ti's density is ~55-56% of steel's. Supertech makes stock sized valves for the EG33 (SS intakes, Inconel Exhaust), so I'd think that they'd be a good place to start for Ti retainers/keepers. If memory serves me right, I think you can get a full set of valves from them for around $500-600. Bill
__________________
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 |
#35
|
|||
|
|||
Re: Camshafts for the EG33.
Correct me if I'm wrong, but supertech lists the EG33 valves as: 92.1mm intake, and 92.7mm exhaust. Stock lengths are: 90mm intake, and 90.85 exhaust.
__________________
'92 SVX LS Pearl White - 6mt |
#36
|
||||
|
||||
Re: Camshafts for the EG33.
Quote:
Intake Valve -- SIVN-1080 -- 36.00mm Head Diameter, 5.96mm Stem Diameter, 92.10mm Length Exhaust Valve -- SEVI-1080 -- 32.00mm Head Diameter, 5.96mm Stem Diameter, 92.70mm Length Which matches what you've noted. Not having my shop manuals with me, I'll have to depend on others here on the Network to confirm the stock lengths. I'm not sure why Supertech would offer non-stock length valves, given the inherently limited audience for them in the first place (i.e., larger audience for stock than non-stock??) Bill
__________________
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 |
#37
|
||||
|
||||
Re: Camshafts for the EG33.
Well, it seems that slightly taller valves, taller springs, and reground cams (smaller base circle) would work nicely together with hydraulic buckets and allow for more valve lift than the stock valve train would normally allow.
|
#38
|
|||
|
|||
Re: Camshafts for the EG33.
Bob, aren't the valve springs the limitation to getting lift? If they've changed the installed height, they'll compromise the installedp spring pressure too...which would have disasterous results (just ask me).
M |
#39
|
||||
|
||||
Re: Camshafts for the EG33.
Quote:
Which makes sense. Why then doesn't Supertech offer springs to go with the valves? Are the EZ springs interchangeable with the EG's? Bill
__________________
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 |
#40
|
|||
|
|||
Re: Camshafts for the EG33.
Doh...I misread the slightly longer springs bit...my bad.
Sorry Bob. M |
#41
|
|||
|
|||
Re: Camshafts for the EG33.
Quote:
The EZ30R runs 10mm lift on solids, this is common on a lot of production engines, not really a race motor. Quote:
You say that the flow bench shows that 9mm is really the maximum lift for flow. That is when the area of the open valve matches or exceeds the valve throat area, and the throat dia is limiting the flow. What the flow bench does not show is how much, when, and for how long. If you use 9mm, you are getting the maximum flow at maximum opening point, for maybe 10/15* but each side of that it is not maximum. it is either opening or closing, and port flow is at less than max. This is a diagram of two 240* profiles, one at 9mm and one at 12 mm You can see that the line at 9mm shows the max port flow, which the 9mm lift cam just reaches, for 10/15*. The 12mm lift cam reached the 9mm max port flow early, and it maintains max port flow right through max lift, till the valve has closed down to the 9mm lift point, almost 90* of max port flowing air into the cylinder. This is the benifit of using the higher lift. You also say " massive duration ", massive duration is for massive rpms, but you are only reving to 7000, the standard duration will cover that speed without any loss of torque spread. Harvey.
__________________
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. |
#42
|
|||
|
|||
Re: Camshafts for the EG33.
Quote:
Quote:
Quote:
Last edited by bazza; 08-02-2012 at 03:56 AM. |
#43
|
||||
|
||||
Re: Camshafts for the EG33.
Quote:
A lot of people don't, and instead they order cams that peak at *exactly* the lift at which max airflow is achieved. There is far more 'area under the curve' when you approach it the way you have. Without altering the seat-to-seat duration, you have effectively increased the duration of the cam at peak airflow. More time to fill the cylinder without increasing overlap! |
#44
|
|||
|
|||
Re: Camshafts for the EG33.
Quote:
If the valves and ports are big enough to flow max air, and the pressure difference between the inlet tract inertia outside, and the negative sonic pressure inside, we will achieve the best Volumetric Efficiency, and the best torque. All the cam timing has to do is shut the inlet valve when that pressure is achieved. The four valve engine doesn't need valve overlap like the older two valve engines, that relied on exhaust inertia to pull the inlet air down the tract. In the two valve hemi chamber the valves are opposite each other, but the inlet port was angled to direct the air down and to the side of the exhaust valve. The four valve chamber has the inlet ports directly opposite the exhaust, so at overlap the air goes across the roof of the chamber and out the exhaust. So we don't need overlap to start the air flow, as we can use the greater negative sonic pressure to start the inlet wave. This is why the duration of the four valve is a lot less that the two valve engine. We only need to open the valve on the negative pressure, that we can time to arrive, by fixing the exhaust length. Harvey.
__________________
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. |
#45
|
|||
|
|||
Re: Camshafts for the EG33.
Some good theory there guys.
Out of interest Harvey, have you got a built EG33 sitting in your shed with this theory applied? I find a lot of people love to give advice based on sound theory but very few of those people have actually put their own hard earned money into what they theorise about and fewer have proven results. I imagine you will have and I'd be interested in what it's running etc. Last edited by bazza; 08-04-2012 at 07:22 AM. |
|
|