crazy280

Optimizing the rod/stroke ratio by lengthening the rods only slows the piston at the top of its travel. That means the PEAK speed the piston reaches will be less, but the AVERAGE speed remains the same. Because no matter what you do, the piston still must travel twice the stroke for each revolution. So hypothetically, you could counteract the wear of added stroke by optimizing the rod/stroke ratio. Unless you already HAD the optimum ratio, in which case you're screwed Also realize that the block has limited deck-height, so you can't always increase the rod length to match your new crank (even with short-skirt pistons). I'm not saying he should reduce the stroke on his SR20DET, just saying if he wants it to rev he should probably stay away from the stroker kits Just my opinion.

Although it does add displacement, stroking an engine actually decreases potential RPM capability. The key factor is "piston speed" at a given RPM. The faster the piston travels at any RPM, the faster the rings and bearings, etc, will wear out. Example: an engine with a 3" stroke. The piston will move 6" for every revolution (up and down 3"), which means at 5000 revolutions per minute (RPM) the piston is traveling 30000" per minute, or 2500 feet per minute (FPM). Suppose you increase the stroke to 3.5". Now with the same engine at 5000 RPM the piston speed becomes 2916 FPM, which is about 17% faster piston speed AT THE SAME RPM. This means everything is under more load at any givin RPM, which means the potential to rev has been decreased, or the engine life will be shorter. In some cases you won't rev the engine very high, so the added displacement from stroking the engine is more beneficial for making power (such as a big V8 with a 6000 RPM redline). If you want more displacement AND more revs without shortening engine life, then boring is the way to go. But I guess there's not many boring options for the SR20DET, so I guess I would say either rev it or stroke it, but not both if you want it to live. Hope this helps

I agree that lighter wheels/tires are almost always better. But something to consider is the "type" of wheel, rather than "just" the diameter. For example a forged magnesium wheel is almost always lighter than a cast steel wheel, even at larger diameters. Hypothetically you could go from steel 14's to forged mag 17's and actually lose weight. Also, many professional race cars have been very successfull with huge wheels, such as group 5 porsches back in the day with 19" diameter wheels (and that was back when 19" was totally unheard of). I'm not saying bigger is better, just saying that bigger is not "always" worse. It's something to consider

Adult Swim is the SHIZNIT!!

In my oppinion, as long as you're making serious power, the flares are cool. It doesn't really matter how you make the power (4, 6 or 8 cylinders) as long as you make it. If you don't have the power, don't do the flares, because flares are pretty lame on a gutless car LOL. Also make sure to have some wide tires underneath them. It looks weird to have huge flares with skinny-@ss tires.

Actually a clutch is more efficient than a torque converter. Compare power to the wheels figures from the same engine with manual and then with auto trannies and you'll see what I mean. I like sticks more than autos, but that's just me Those new "paddle shift" manuals (as seen in Ferraris) are cool. They have a clutch, but it is electronically activated. I read that they had Schumaker run laps in the car and they data logged his RPM and etc. and then used the info to program his clutch work into their paddle-shift computers. BMW uses a "sequential" manual, which has a stick to shift with, but is like the paddle-shift trannies in that the clutch is electronically activated. These trannies are supposedly worth half a second in the 1/4, becuase they shift much faster than a human. Cool stuff!

Well, if what you say is true, and it is only 2/5 of a percent weight on the front axle, that would mean putting 100 pounds more in the front of the car only adds 4 pounds more to the front than the rear. Maybe the decimal got misplaced, remember, .02 means 2 percent. What if you put 100 pound heavier axles in front? Would that also only change the weight distribution .2 percent?

John, I think you misplaced the decimal. It should be .52/.48 For example: a car with 1000 lbs on each axle has a weight distribution of 1000/2000 for the front and 1000/2000 for the rear, which is .50/.50. Whereas a car with 1100 lbs on the front axle, and 1000 lbs on the rear axle has 1100/2100 for the front and 1000/2100 for the rear, which is a weight distribution of .5238/.4762 (roughly .52/.48 ) which is a significant change in weight distribution for a road-race car. Please correct me if I'm wrong.

My best friend's first car was a '67 Baja Bug (basically an offroad kit for the Bug). I spent a lot of time helping him work on it. He had a tuned 1600cc dual port engine, mags, etc. Even tuned out its hard to get more than 100 hp from those things (unless you drop cubic dollars on a Scat engine or something similar). I don't know about the later bugs, but the earlier ones weigh much less than a 240z, more like 1800 lbs (maybe less) stock, so gut it and you are talking about a VERY light car. Part of the Baja Bug kit is fiberglass front end and fenders, so his was very light. Heavy rear weight bias, not good for racing, but probably good for drifting. Parts are cheap, too.

I just looked at your photo album.......wow your car is one of a kind, stunning! I think you win the race just standing still.

Wow, sounds like a whole different car. I don't think you have to go that far with mods. Sounds cool though

hehe....."asston"

SR240, I saw this car a while ago, and never got around to saying how f-ing beautiful it is. I love the wheels and the flares. I always thought 17's looked perfect on a Z until I saw those 16's, they look gorgeous! Excellent fit and finish on all the fabrication. So did you ever get it weighed? Hugh and Superz, You guys shouldn't argue over rearend ratios without including the tranny ratios that you're using. Its like one guy with a .75:1 top gear and a 4:1 rearend, arguing with another guy who has a 1:1 top gear and 3:1 rearend ratio (both have the same wheel-speed). Just trying to help

DAW's right, you should keep the emissions. I just wasn't sure if the 280 stuff would be compatible with the early 240 stuff, but I guess it is, so you should keep it.

you bastard! I paid more than that for just the dizzy! LOL But seriously, good work.

Hey, I AM "all that and a bag of chips" lol just kidding John, I get what you're saying, but here's what I'm thinking: The sr20det weight is 490 with crossmember, transmission and ALL accessories (the stock intercooler and piping was included). So even with a bigger intercooler, the total weight should be around 500. Lets say you weighed the L6 with the crossmember, trans and all accessories. What would it weigh, around 580? Not only that, but with the SR you can put the intercooler very close to the engine (plenty of room left over in that Z engine bay!), with big hood vents to help draw the air and let it exit (like the front radiator setups on midengine exotics). That puts the weight farther back and requires less piping (saving weight). That's what I'm thinking as far as SR vs L6 anyhow. Of course, my ultimate setup would be LS1, or a tuned VQ35DE, hell yeah! Oh well, I'm stuck with the L6 for a while lol. PS: that Cobalt was badass!

From what I've learned, JohnC is right. The modern school of thought regarding weight distribution for road racing is to have a slight rearward weight bias to take advantage of traction during acceleration, braking and while accelerating out of a corner. Most purpose-built road-race cars (LeMans Prototypes, F1, Indy, ChampCar, etc) are midengine, rwd, and have a rearward weight distribution. However, too much rearward weight bias can make it difficult to control oversteer at the cornering limit (think Porsche 911). Where I disagree with JohnC (respectfully ) is that I was taught to minimize PMOI, and to keep the car stable with suspension adjustments (toe, sway bars, etc). Hence the advantage of the mid-engine layout. Even front engined cars are optimized by moving the engine down and back as far as possible in the chassis (think: Corvette, RX7, and JohnC's 240z). The SR20DET should be the best for road racing, becuase even with IC/etc the SR is much lighter than the L6 (490 lbs with crossmember, tranny and all accessories!!). If you optimize the placement of the engine and IC, the weight distribution should be perfect, and the overall weight should be less than it would be with the L6. I don't know all the stats on Amir's car, but I would wager that it does not have optimal engine/IC placement, or that it was heavier to begin with than JohnC's car. Of course, JohnC obviously has MUCH more experience in this field, so he's probably right...damnit lol

The little "capacitor thing" (its not a capacitor) attaches to the alternator, but I don't think it should affect the charging. There should be a small bracket with it that bolts to the backside and a wire that connects to the alternator. And if I remember correctly the 280z alternator was internally regulated (at least mine was on my '75). Double check your wiring diagrams and make sure the alternator is wired correctly, also check the water level in your battery (if applicable), check the belt tension on the alternator and check your fuses. Hope this helps. Good luck

Exactly!

First off, nice screen name! You'll also need to deal with matching the emissions to the older carb setup. SU's are super easy to tune and adjust and run great. I have a set of them for sale, with everything you need, if you're interested give me a PM.

Randy, FYI it says that DOT 5 fluid is NOT good for performance

I remember reading that the Northstar can't be rebuilt, because you can't overbore the cylinders and you can't re-sleeve the block. I could be wrong here, but I'm 75% sure. GM sells brand new Northstar crate motors now, for a few grand. Hope this helps.

I'd say go for it as long as you can afford the maintenance cost. My best friend is a mechanic at a shop that specializes in BMW's. He's always complaining about how unreliable the 3 series are, how they have plastic water pumps that go faulty, parts are expensive, etc. (not to mention his shop charges $75 per half hour!!) But he does compliment the build quality and finish of the cars, which is obvious and cannot be denied. I've driven a few E36 M3's and they are fast and fun to drive, and very comfortable. Happy hunting!

LOL right