Leon

I agree with that John, and I wasn't trying to imply that open headers is the "best" exhaust design. I think I should have clarified my statement a bit better. A stock car (i.e. a Z) will make more power with a 6-into-1 header without a "typical" pipe (say 2.5" with the tip at the rear bumper) than with the pipe. That's what I meant by my vague description of a "pipe connected to the exhaust." Now when you get into exhaust tuning, of course you tune for certain lengths which give you resonance effects at certain engine speeds. The megaphone can be thought of as a bell-mouth for the exhaust. Megaphones help broaden the bandwidth, if you will, of the pressure wave reflection (resonance effect) as the taper of the megaphone pipe can be thought of as infinitesimal "steps" with a pressure wave reflection at each step. It's the same deal with intake bell mouths. Megaphones are surely beneficial, but sadly you don't find megaphones attached post collector on most factory cars, and they are even excluded from many custom built street exhausts! Hence, taking off the long exhaust pipe, and leaving an open header increases torque. Now, this leaves the option of building a new exhaust that can make performance even better, but the original point I wanted to make was that a long "typical" (no megaphones, no specifically tuned lengths, etc.) exhaust pipe is detrimental to performance. You gain torque by removing the pipe and running open headers, and then even more torque can be found when you add things like megaphones and tuned lengths post collector, as John mentioned. Thus as already mentioned above, when people are having 2.25" or 2.5" "typical" NA exhausts built, they are still making a performance sacrifice (and no, you don't lose low end torque ).

Those are good points, and are topics that people usually don't consider when talking about exhaust design. I agree that large exhausts definitely help a turbo spool faster, but I also think that they help naturally aspirated engines. There is a lot of evidence that a properly tuned engine makes more power with open headers vs. having a pipe connected to the exhaust (contrary to internet myths). I believe the reason for those results is that a lot of the cylinder scavenging occurs in the headers (given that they are adequately long and merge into one pipe), and the exhaust pipe is mostly just there to route the gasses to the back of the car. There may be some resonance effects dependent on pipe length, but as I've implied, given the header is adequately long (length is dependent on where you want your powerband), any effects generated by the pipe are likely negated by frictional losses. Thus, this long skinny pipe increases frictional losses in the exhaust flow, increasing pumping losses and decreasing volumetric efficiency while not really helping anything. So, you want as little friction loss as possible, while maintaining ground clearance. Essentially, you want the pipe to act as the atmosphere. Another point that was made is that friction in the pipe(s) is dependent on surface area. The flow sticking to the pipe is a good way to visualize it. This is the concern I have in using MSA twice pipes, as that is what I plan on getting when my Z is built. The cross sectional area is roughly equivalent to a single 2.5" but the twin 1.75" pipes have more combined inner surface area, and thus there will be more losses. Whether performance is affected much, I don't know. When I'm ready, I do want to do some exhaust dyno testing to show myself which setup works best. Keep in mind, my post is based on a combination of theoretical knowledge and experimental data. If someone has done some relevant dyno testing that would be great! If I missed anything, feel free to contribute.

Good find! Any guinea pigs takers? I'm curious as to what the weight difference would be when compared to a factory shell...

Here is the free one: http://sfbay.craigslist.org/nby/cto/1724090801.html It looks like it needs a lot of work (and parts) though. I'll keep you posted on mine as I have another shell, so one of them has to go. The reason I can't sell it now is because I'm in SLO and the shell is in the bay area. Once I put the suspension back on it should be ready to go, unless you want the shell and suspension separate, in which case the shell has to be able to roll around somehow.

I'll likely be selling a 1971 240Z shell pretty cheap this summer, in the SF bay area.

Both as they are intertwined. My engine would knock around 3000rpm and up, even with retarded timing, high octane, and a rich mixture. Stupid distributor cap...

I had a similar issue on my L24. It turns out that the new distributor cap didn't fit well, and did not seat correctly. Just to rule out the possibility, make sure the cap is seated well around its whole perimeter, all 360 degrees. I only noticed this when I pulled my distributor. That's my off the wall advice!

Wow, you cleaned her up really nice, great work!

Sorry you're so upset about that, but the term "NVH" is not street-slang, nor is it text message or IM shorthand. It is analogous to saying WOT or EFI. I'm just saying, a one-second google search would easily show the answer. Digression over.

http://lmgtfy.com/?q=nvh

I'm having the same issue, been thinking the same thing... I've noticed a lot of people double and triple posting more often, so I'm guessing this is some site issue?

You think $250 is a lot, LOL! This guy has been asking $400!!! I wonder why they haven't sold yet...

Get the FSM and study how the EFI system works. The Tech Tips link also has a lot of good info. http://www.xenons30.com/reference.html

Holy S***!!! That's how I felt when I saw that. You're right, I did not see that coming!

Not trying to sound harsh here, but the problem is your driving. You are lugging the car, as this is not your old Chevy 350. Downshift and you're good to go. I'd keep the revs above 2500rpm. If you still get resonance you can put a resonator a bit downstream of the exhaust manifold. Sound reduction will depend on which resonator you get.

I agree, as you know you're getting a good deal for a nice car with the Three. If you want carefree and comfortable the 3, or a Honda is really the way to go. On the other hand, if I was you I'd strongly consider an E36 BMW. Yeah, they are older, but that just means you're spending less, and you can probably go out and find a nice example for a relatively low amount of money. My dad and I found a '93 318iS with 5 speed and 200,000 miles at an auction last year. It is in very good condition for its age. We replaced the oil, front control arms, some bushings and the radio. I've driven it a few times and even though it's a 318, it's a hell of a lot of fun to drive! Feels very tight, engine has good compression (10:1 factory!) and BMW just makes (made) everything feel right. The E36 really is well done. If you find a good example, save yourself $10k and have a fun DD. You'll have to do some maintenance, but if you can do simple stuff you'll save some cash there too. They're not hard to work on. My brother drives the car now (S/C Previa died) and it really makes me want to get an E36 (6 cylinder, the 4 is lacking for my tastes) as my next DD, although I've been salivating over S2000s for a long time now. Good luck in your search!

I was just talking to a bodywork/paint friend of mine recently about painting my Z. He said that if the original paint is in "good" condition (i.e. no cracking, peeling, not easy to remove) then there should be no need to completely strip the paint. As said above, scuff it up so the new stuff adheres to it and you're good to go.

Good point. I'd be running triples if I had a set. I suppose the simplicity of the dual SU setup comes with its fair share of compromises. Thanks! Leon EDIT: To keep this on topic, I'm thinking the O2 sensor port you're (OP) talking about is really an EGR port. I don't think MSA headers come with O2 ports, but I may be wrong there. With that said, it makes sense to have the O2 located after the primaries, or else you're not getting the big picture.

That's very interesting insight! Did you try other SU manifolds (N36?) for comparison? I'll be running SUs when my engine is finished so I'm definitely interested if you have any other info on this.

Haha, those bits of wire get me every time! I'll check out the scotchbrite wheels, good tip. I've been using this paint (got it at Home Depot) and mine have been turning out pretty good, I just hope the paint lasts. Good luck!

He is obviously employing the principles of Milliken's Camber Car :

Nice work, I've been following this thread for a little while. I've been cleaning up and painting my suspension parts as well. I was curious as to what your method is, and what have you been using for paint? I've been cleaning mine up with a wire wheel (angle grinder), light sanding where needed and then applying some rattle can Rustoleum. Your parts look very nice!

Look for rust on the body.

Yes, a mark that shows the alignment of the caps with the head. Here is a quick search result: http://forums.hybridz.org/index.php?/topic/79242-can-the-hole-in-the-cylinder-head-for-the-cam-tower-bolt-be-repaired/page__p__752837__hl__removing%20cam%20towers__fromsearch__1entry752837 Link from resulting thread: http://community.ratsun.net/index.php?showtopic=10760