katman

If it was me I'd go with the bigger valves, or start with an N42 head. After that, money spent on dyno tuning will far outperform any head work you do, epecially with a carb setup. Just my 02c.

Well not that it matters now, but the twice pipes system bolts in, no trimming needed. It is not, however, the hot tip wrt power.

Doh! Thanks for that correction. Problem with surfing at home is my computer glasses stay at work. 15-ft lbs with an exhaust change (even with header vs stock manifold) is a lot, but considering the jet change that's easily possible. I see 10-15 ft-lbs murdered on the dyno easily by running fat, even on a near stock L24 ITS motor.

Uh, 30+ ft-lbs increase with just an exhaust system change? That don't pass the giggle test. You have a 'tater stuck in the pipes of the old system?

Are you implying that you got all of one type, intake or exhaust? The exhaust guide has a 3mm counterbore in the bottom end and a blunt, rounded exterior. The intake has about a 30 degree chamfer on the exterior and nothing but bore on the ID. Both are identical other than that. Valve stem to guid clearance is different intake versus exhaust but it's the valve stem that's different- guide bores are an identical 8.000-8.018mm finished. Don't go overboard on cutting the bottom of the guides back to the port surface- that's mostly mental masturbation and ain't worth the extra wear. But yeah, I suppose you could make intake guides from exhaust guides but I think it'd be tougher going the other way.

I was going to do this a couple race cars ago. The BMW motor would be lighter, but like the Jag the intakes bump into the shock towers with any kind of reasonable air cleaner tract. I was going to go custom manifold in that regard, and put a Supra 6 spd Tremec tranny behind it. Decided college for the kids was more important. Do it, and send us the pics!

That's Alan Poindexter's car. Not sure if he ever sorted it. Sure is a deal if you were thinking about building something like that. Practically new. JohnC- chose the ball peen hammer. The pain will go away quicker.

The cat's meow in L series torque plates is owned by Don Potter and is much more than just a 2 inch thick slab of steel. He developed it by actually measuring the cylinder wall distortion between a real head and his torque plate and modifying accordingly. He also bores at temperature using a new gasket each time and only after the assembly sits for at least 4 days to get all the creep out of it. Of course, it also takes him at least a year to build a motor, that is if he actually ever finishes. But when he does, big power and long life.

You may also need new rocker guides (lash pads). Cam tower shims affect your wipe pattern.

These were designed for racing apps, when you have the engine out all the time. Some have had good luck with them, but I've replaced 3 that seized up on street cars. No advantage over the stock bushing IMHO, just some mental masturbation. Fuggetaboutit would be my recommendation, even for a race car.

Don't believe head saver shims would be legal, but until you win something nobody would care if you had a 3 liter. Remember you're allowed .025 total off the head thickness for shaving, starting at 4.248". That doesn't mean, however, that you can just go whack .025 off the bottom, because if you did that on an E31 or early E88 you'd end up past the 9.5:1 comp ratio you're allowed. But again, for a mule, who's looking. Just keep that in mind for when you're ready to win the ARRC. Definitely start hanging around the Datsun forum at improvedtouring.com.

I've worked with those guys too. The kind of people who you fear for every time they cross the street, because they're working on that "five dimensional array" instead of looking out for cars. Pulled up beside at a coworker of mine once who appeared to be walking home. 'Bout 400 yards from the plant, briefcase in hand. I say "Hey Fred, you want a ride home?' He says "No thanks, I have my car." About a second later it hits him that he does in fact have a car, and its in the parking lot. I was thinking more along the lines kids who are so used to everything being fed to them that they're really just "lazy brained" for lack of a better term. But good example, John.

Ah, well said and an opportunity to pose a theory of mine to the smartest forum of the many car groups in which I lurk. My theory is we're currently raising the dumbest generation (actually I think I saw a book by that title recently). Because of video games, dumbing down of school curriculums (every body passes, wouldn't want to hurt their little self esteems!) etc., the current generation never does any critical thinking. They don't build models, take things apart, find their way around town on their bike, find something to do when all you have is a stick and a pile of dirt, blah blah. They have no imagination, which I think is crucial to problem solving. I see a lot of kids that want to sit in front of the computer and operate a spreadsheet or some other program, but dang few that could write a program or solve an engineering problem. "Figure it out" is met with a blank stare and no progress. Anybody else notice this trend? Oh, and I'm sure all the Phd's on this forum are different, but in the aeronautical engineering world they're some of the dumbest people I know. Book smart, and can't do a thing with it.

That was the Credible Sport program. We were going to land in the soccer stadium across the street from where the hostages were. The crash at the end of this video was caused by a crewmember hitting the "stop" button too soon. We built two of these, the other one is still at Warner Robbins AFB museum if I'm not mistaken. Didn't quite have all the bugs ironed out before Carter went with the now infamous helicopter rescue/debacle. IBM did the computer that timed the rocket firing. I blame them.

Yup, Malvern had done it, and Don Potter has done it. Potter used to say that it took 75 hp just to drive a stock Z cam at 5000 rpm, so imagine the potential once you eliminate most of that drag. Of course with the geometry change going from rocker to roller it requires a custom grind, which both guys had worked out. And Don was especially good with the metallurgy. Not sure how Don is doing, or if he's still alive. The "cheerful curmudgeon" was poster child for a heart attack.

And if I'm not mistaken your Oberg has a bypass valve and a sensor to tell you when it's bypassing. I also go filter first.

LOL!!

Aluminum forks. Never broke any forks. Did wipe the teeth off of 3rd gear once. Downside of having to use 30 year old tranny's....

Broke lots of pins with various ITS racers. Tried the double Comp pins (pin inside another pin) and the ZX stock pins (single piece of steel rolled into 2 layers). Safety wire wouldn't do anything. Eventually went with 4m solid bolt stock. End of problem. Time spent shifting is time wasted....

That's the MSA 6-1 header. Get them new here: http://www.thezstore.com/page/TZS/CTGY/PEC01 It looks like a header and sounds like a header, thats about all I can say about it. If you want a performance header check out the Stahl headers also available at MSA.

Keep this in mind- looks cool, sounds cool, but on anything close to a stock engine we always lost power with a dual setup compared to a single pipe when running 6-2 headers. And not a trivial amount either. Just a FYI....

Jon has it right, E31 not a good choice for a turbo. Not a great combustion chamber (better than a late E88 for sure, but nothing special) but it's biggest downfall for a turbo is volume. When you're cramming air into the combustion chamber more is better. 55cc boosted to 7psi is a whole lot more air/gas/power than 43cc boosted to 7psi.

I had an original Gleasen Torsen for an R200 that I did put a few street miles on and about 70 at Road Atlanta in a 240Z. No bad habits. Sold it a year or so ago to somebody from hybridz. Should work just like a Quaife.

Caught me in a senior moment. 300/100 was correct, 70/30 is terminology used by someone else. Yes, same valving at 300/250 rates and good up to 400. The EP car tried many things in that range, same shocks until we put freshly banned ShockTeks from an IT car on it. I think on page 6 I was recommending against this setup for a street car. Make sense? No prob putting me on the spot. If I say something that don't jive then please call me on it again.