Leon

While valve lift is somewhat dependent (metallurgical/physical issues) on duration, I don't see why you'd want lower lift at lower rpm unless maybe you factor in some mixing processes (tumble/swirl). Ideally, you'd have maximum valve lift over the duration of the valve's open period, or essentially very fast ramp rates in order to increase cylinder filling (VE). A lot of people put too much focus into port velocity. The main function of port velocity is to keep the mixture distributed and the fuel atomized in a carburated or throttle-body fuel injected engine. There are kinetic effects that occur at higher speeds that are slightly dependent on port velocity, but really you want those ports to be big. Cam duration (along with port and manifold design) is what really controls VE over the operating range of the engine, given a high enough valve lift. At lower speeds, you want lower duration because longer durations encourage gas reversion, where exhaust pressure is higher than cylinder pressure or cylinder pressure rises above intake pressure. At high speeds, you want longer duration since gas speed is higher which increases both intake kinetic energy as well as exhaust scavenging, making longer durations more efficient. A cam is really designed for one operating point where it is most efficient. Being able to alter this point as the engine accelerates is a huge bonus. Changing it continuously would be even better. Many modern engines already do this. If I had a choice of constantly varying a part of the valvetrain, variable valve duration would be on top! Although variable lift is cool as well, especially when the intake valve doubles as the throttle, like BMW! I think I've digressed a bit, but it's an interesting topic! I've had some free time to dig into Heywood's IC Engine Fundamentals...

That's not quite what anti-lag is. Anti-lag systems typically retard spark timing and dump in more fuel in drop-throttle conditions (shifts). The much higher gas pressure and temperature caused by this are then used to keep the turbine spinning faster than it otherwise would be. It is true that anti-lag decreases engine and turbine life.

Hope it's the latter and not the former!

How do people adjust them without a wideband gauge or dyno? You do the best you can. Doing everything the same on each carb is a given, but ideally I would love to have an 02 sensor for each cylinder. Using one wideband is not ideal, but it's a lot better than not having one at all. A competent person can get the carbs dialed in pretty well with a WB02. A dyno is even better.

Generally, slightly rich with lambda of ~0.9 (13.1 AFR). Specifically, it's what the dyno says.

Or to Pertronix...

In a nutshell, mains affect mid-range and top end. Bigger mains make the mixture richer. Air correctors affect top end, where a bigger air corrector makes a leaner mixture. A wideband 02 sensor is very helpful in the tuning process. The Weber sticky has very good info: Linky. There should be some pertinent Mikuni info as well.

Yes, you are right on the first point. By changing the steering axis offset, you can increase caster and still have zero mechanical trail. I think that you would have to redesign the steering system of the car to achieve that though. I think that what I meant to say didn't come across right on my point about feedback. Mechanical trail and pneumatic trail added together gives total trail, which directly affects the torque required to turn the steering wheel. However, the forces produced by virtue of the pneumatic trail are non-linear and dependent on tire characteristics. The forces produced by virtue of mechanical trail are linear and proportional to lateral force. Therefore as mechanical trail increases, driver feedback from the tires (pneumatic trail) gets drowned out. I am not saying that the actual pneumatic trail decreases, what I'm saying is that the effect from it is lessened since mechanical trail dominates (as caster increases with steering axis offset held constant). Thanks for the correction. Leon

Make sure the progression ports are not open at idle. They must all be covered by the throttle valve. Check this sticky out. Make sure you read and understand it, it's got pretty much all the info you need. I also recommend this book.

Thanks, I'm in San Bruno. This was actually down the street from my house. I got a call from my dad who told me that there was a huge explosion by the house, while I was walking the dogs at a nearby beach. It scared the crap out of me, but luckily I found out that it's not a threat to us. Unfortunately, that whole neighborhood is obliterated and I know some people that lost their homes. If anyone needs help, let me know. Leon

Great info John. I'd like to add that more positive caster will also increase steering effort and it would decrease feedback to the driver since the mechanical trail would make up a larger fraction of total trail. It's the self-centering characteristic of pneumatic trail that gives feedback through the steering wheel. Just a few more things to keep in mind about changing steering axis inclination. Please correct me if I'm wrong with any of this since this comes from memory and not actual hands-on experience.

Thanks for the heads up, just picked one up in SSF today! I managed to find one in orange, had to dig for it. The period correct license plate and VIN on the dash is a nice touch. Speaking of the VIN, it's only 68 cars ahead of one of my '71s! Anybody have HLS30-25008?

I think it will sound glorious, make sure you get some sound clips! Great job so far, I'm loving the fab work.

No problem, I always thought it was a cool setup. I never thought of applying it elsewhere though, that would be great to see! That van was an awesome sleeper.

http://partners.academic.ru/dic.nsf/enwiki/621088

The S/C Toyota Previa had an electromagnetic clutch that engaged the supercharger depending on load. Too bad the head or head-gasket cracked when ours approached 200k!

Rockauto has pretty much always been great about getting the parts out quickly. Usually I get my stuff from them two or three days after ordering, with regular cheap shipping! Just got some con rod bearings, and as usual they came in three days. The prices are usually great as well.

Hidden answer, I'll take the M91/30! Apple or cherry pie?

And that's why I loved Cal Poly SLO! Tons of hands on work that really lets you dig into the stuff you're studying. I'm still trying to find work but I feel confident that I can take on whatever task is at hand whether hands-on or not. I've been waitlisted for all my classes and gotten then all. Gotta be persistant! It is definitely going to be weird not having classes anymore...

I actually called the guy, and then saw the joke! Guy said he's selling it for $6000, way too much.

That's awesome, I love MST3k!!! Haven't seen an episode in ages...

Acrylic sounds interesting, and it can be cut with a router or most any decent rotary tool. I wonder how well paint would stick to it. Acrylic can be bought from places like McMaster for some DIY fun!

I don't think it should be a huge deal, that's where my other tapped hole is I believe. The hole would be close to the balance tube anyway, so I don't think the effect will be detrimental to performance, and likely to the contrary, be beneficial. It's what I'm planning to do with my triples, so hopefully it works fine that way. You can use a Coke can as a catch can if you want to. No big deal there.

I have triples as well that I will be installing and I was thinking of using the hole in the intake that's provisioned for the vacuum advance for the PCV instead. I don't know how many vacuum provisions you have in your intake, but I have one for the brake booster and one for vacuum advance. I won't be using the vac advance (I'm using the ZX dizzy for my 240Z as well) so I figured that tap is good for something. I'll have to check the threading of the PCV valve and see if I can screw it into the manifold. If not, it can probably be connected in between two lines with one routed to the block and the other to the intake manifold. Like I said, the catch can is your other solution.

That hose looks like the one for the positive crankcase ventilation (PCV) system. It should be plugged into the PCV valve. I see that your running triples and don't have a PCV valve so you can route the hose into a catch-can. Not the best solution but it should work.