johnc

What can I say. I've done a couple more SR20 swaps but was only able to weigh one of them and the results were similar to what I posted above. I think what's confusing people is that I generally build race cars so there's a focus on weight savings. If that focus is applied to any S30, the cars can get down to similar weights regardless of the engine/transmission installed. When the weight savings focus is on the SR20 swapped car and not on the other car used in the comparison, then the comparison is useless. Another example is the folks that say the SR20 swap has much better weight distribution then a NA L6. Well, that's not true either if the car with the L6 has its engine moved back in the chassis like the SR20 swapped car. But again, most comparisons are between a SR20 swapped car with the engine moved back and a stock positioned L6 engine. That's not a fair comparison.

Four of those tires on four 22in wheels will weigh more then a stock 240Z.

I've had similar experiences at gun stores. My guess is that a lot of people open gun stores because they like guns and have little to no knowledge about running a business, customer service, or providing a positive shopping environment. Dressed in leather and looking pissed at the world is only good if you're selling S&M.

I too am sold on the Quaife, although I'm really impressed with the OS Giken SuperLoc I put in my 350Z. FYI... I bought two Quaife ATBs and a Quaife Sierra Sequential 5 speed dog box from Craig at Taylor-Race.

http://www.sae.org Some examples: http://www.sae.org/technical/papers/2008-01-1004 http://www.sae.org/technical/papers/2002-01-0059 You can even sign up for a seminar on how to design high performance exhaust systems: http://www.sae.org/servlets/pdEvent?OBJECT_TYPE=PDEventInfo&PAGE=getPDEventInfo&EVT_NAME=C0235

Ever heard of Pro Stock, Pro Stock Motorcycle, Comp, Super Comp, Super Gas, Super Stock, Stock, and Super Street?

I think that's why Mark said above that the ATB diff can be slower around a race track then a high lock percent CLSD. If the inside wheel contact patch can only handle (for example) 100 ft. lbs. of torque and the ATB bias ratio is 5:1, then the total torque at the contact patches is limited by the ATB internally (through heat) to 600 ft. lbs. - even though the outside tire might be able to support 750 ft. lbs. of torque at the contact patch with its greater grip. With a high lockup percent CLSD you can get that 750 ft. lb. of contact patch grip but you'll be dragging the inside tire a bit and creating a push. On paper, you should be able to exit the corner faster. In reality, if you can drive through the push, you might be able to be faster for a couple laps until the rear tires get greasy.

Its very hard to compare VLSDs because there's such a huge variance between the VLSD units installed in vehicles. The stock VLSD in the 350Z is fine for street driving but basically useless for autocross and track use. They heat up and stop working. Conversely, there are some very high dollar ($5,000 and above) VLSDs that are the best you can get for very specific rally and road racing applications.

I would do a lot more research on that 327 before plunking any money down.

Uuuuhhh, I asked the question and it wasn't about computerized yaw control. Mark just went in that terminology direction with his response. I was interested in how differential types can affect yaw and I guess using the term "control" translated to computerized control systems in Mark's head. In my experience the HLSD can provide easier and better handling (turn in, power out) then a high lockup percent CLSD and can result in faster race lap times because its easier to drive fast. But my experiences also show that high lockup percent CLSD (even a spool) can ultimately turn faster qualifying lap times if a fast single lap is the goal. Again, from my experiences, if heat generated is a measurement of power used in a diff, then the order is spool, CLSD, then Quaife putting the most heat into the diff fluid.

I think this is where he's making the distinction. In a turn you always have unequal amounts of grip available from the tire (outside tire has more grip due to lateral load transfer). The ATB sacrifices ultimate thrust to gain yaw stability and coincidentally not cause understeer.

I've also read Smith and Morrison's book and the last time it was updated was 1972. A LOT has happened in exhaust system technology in the last 36 years. Things like shallow merge collectors, commonly available thin wall 3" and larger tubing, CFD software, etc. Exhaust system science has moved on and Smith and Morrison's book is now really only appropriate for vintage folks. A properly designed single exhaust will generally make more horsepower and toque over a wider rpm band then a dual exhaust on almost any engine type (including rotaries). TransAm race cars for years ran 180 degree headers that merged into a single 5" or 6" exhaust. These engines made 50+ more horsepower with an exhaust like that. Dyno testing I witnessed in the mid 1990s and again in the early 2000s showed that a single 3" exhaust, properly designed, made significantly more horsepower and torque on 2.4L, 2.8L, and 3L Nissan L6 race engines over commonly available and/or highly optimized twice pipes. And another side benefit is that a single exhaust weighs less then a dual exhaust.

Poor shot placement. The outcome would probably have been the same regardless of caliber. I was on a jury where the defendent was shot 7 times in a hallway with .40 HydraShok hollow points, at 10 feet, by two cops, who discharged 19 rounds total. The defendent looked a little worn down at trial, but he was alive and talking.

From Mark Ortiz's latest newsletter. I actually called him on this issue and he asked if he could make it a question/answer for his newsletter.

Its a 240Z guys.

Exactly. Having had to work the technical sales side (I was brought in when the customer's technical staff started playing "stump the chump") I agree whole heartedly. I've canceled deals when the customer appeared too ignorant and I knew things would go horribly wrong once our product was installed (once by asking their database administrator if he did his database design that way on purpose). That earned me the undying hatred of the sales person and the VP of sales, but I had the final word. It balanced out because I saved their butts many times.

Two things to learn from this: 1. Its orders of magnitude better to remove the complete driveline before attempting frame work. 2. It takes buttloads of time setting up/preparing for just about any frame work.

Looks fake to me.

BTW... my nephew carries a H&K USP .45 Tactical in his SEAL jobs around the world. During post BUDS training they swam with the gun in the ocean, buried the gun and their extra mags in the sand, dug it all back up, shot a full magazine into a 2" group at 20 meters, reloaded, and shot a 1" group at 10 meters.

Oops. I assumed a 12ga. A 20ga with #8 would just irritate a big guy. Don't piss off Tony D.

Lots of different opinions on shotguns as home defense. The LE and DoD trainers I've worked with recommend a shotgun only if you're taking a defensive position behind a bed or something else. Legal length shotguns (18" barrel and unshortened stock) require the shooter to lift the barrel up to turn around in a hallway or tight room and will also blow out your eardrums if used in the same places. And 00 buckshot will fly right through 6 layers of 1/2" drywall and still be lethal.

I used to do a lot of IPSC shooting years ago and put about 18,000 rounds through a H&K USP .45. Its one of the early ones imported (serial number around 1,000) and its still going strong. I suggest you look at the .40 S&W version of the gun. Very accurate (beyond my abilities) and the barrel stays clean and true. You can also order it with whatever trigger style you want (SA/DA, DA only, variants). http://www.hk-usa.com/usp_general.html

No. As alluded to above, the independent rear suspension on the Z more equally loads the tires under straight line acceleration. A live axle car loads the tires unevenly (left side more then the right under acceleration) so the right rear tire breaks traction before the left and thus gets all the torque from the open diff. An open diff is an open diff regardless of which car its installed in. The open diff will always send all available torque to the tire with the least amount of traction. If both tires have equal traction, they will both get the same amount of torque until there is a traction difference.

Or its a welded diff, a spool of some kind, or full of sawdust and grease.

Back to the basics: http://auto.howstuffworks.com/differential.htm And an open diff will spin both rear wheels if traction is the same on both sides - something an independent rear does. Also, Posi-Traction is a GM brand name for a clutch pack limited slip differential. Its no different then any other CLSD.