MAG58

Great writeup. I was looking for an EBC that wasn't ridiculously over-priced. I'm glad to see such an informative post on this, and I think I'll be trying it.

I actually thought the same thing. Then again, that is crazy. It even looks like a nice neighborhood too. It's such a nice lookin' GT-R...

The point of a longer rod/stroke ratio is to increase dwell at the top and bottoms of the cylinders. The more dwell it has at the bottom, the longer the time the cylinder has to fill under it's full capacity. What goes with a long rod is less side loading, with less rod angle, more of the stroke is dedicated to up and down movement, thus more efficiency. Along with this lower rod angle, you see less friction from side loading and a slightly cooler running engine. Onto your question, increasing rod/stroke ratio allows for the piston to decel and accell slower at the relative maxes of it's movement, and allows for a longer compression event at TDC. This slower decel (the deceleration is spread out over a longer time) gives the gasses more 'time' to compress, and reduces detonation. Reducing detonation is where efi really shines over carbies. Using a knock sensor, efi has the ability to only advance timing as far as the engine allows without knock. (Though in most cases, it starts at max timing and pulls timing as it detects knock) Carbs do not have this benefit and rely on your skill at timing and tuning to reduce knock. I cannot tell you how much cr you can run in CA since in IN you can get 94 octane from sunoco, but you'd be surprised how much 2 octane numbers can change things. Though if you're dedicated, you can switch to E85 which iirc is about 103-105? octane.

Considering 1 fast Z is one of the more competent machinists and engine builders for L engines on this site (which given his peers is saying something) I'm inclined to believe what he says. If you have something you're unsure of, break out a mic and figure it out. If you don't have one, there are a few auto parts stores that let you rent one, or if you go to your local high school and ask to borrow one from the physics teacher, I'm sure they'll even have one. Also, as i recall, of the original L24 blocks that were sonic tested, they probably wouldn't like the 89mm over bore very much. For the factory L24 that's a massive over bore and starting with an N47 or P90 block would be a better starting point. 83-89mm is a 6mm overbore. That's a .240'' over. Which is a bunch. Though provided you're using KA24 pistons, an E31 head, whatever block makes you happy to get 89mm and a 2mm hks HG, I calculate roundabouts 10.5cr with zero flycut.

If I'm to be completely honest, I'd rather have the KA since it has an Iron block, and SR blocks have to be sleeved much above 600hp. The KA does have a better head, anyone that for a second thinks that forked rockers are more durable than direct acting cam on bucket doesn't really think that much. It's not a fully counterweighted crank, but with 400 more cc's, you don't have to spin it as fast for the same power. What's so great about the SR20? It's JDM Tyte? It's not even that light for being an all alloy motor. ...Back on topic. As much as I'm against 4 cylinder cars in principle and practice, a big RZ motor would be one of the few I'd think about. They put out silly amounts of power and have lots of torque. They're some of the few motors that could consistently pick fights with the factory Ecotec teams in pro FWD.

I'd completely agree. In my town Autozone is the only place that sells sound reactive lights that stick on the inside of your car. Hmm... My current favorite is Advance, followed (tie) between o'reilleys, Pep-boys, and napa.

1. Carbs are a metered fuel leak /lesson. People don't run EFI mostly because of the cost of going EFI or in most cases, they're just afraid of computers and all that gadgetry. Carbs are fine, but they will not be able to produce as much power as they cannot as quickly and variably alter the Fuel/Air ratio. EFi only makes more power because you can safely push the engine closer to it's limits due to the ability of EFI to adjust for knock, temp, etc.

But it's a 2+2... I have a soft spot for 2+2's... That's just sad

Give this man an award, quick.

I'm pretty sure he's talking about things like... Oh, teh interwebz tells me that with this combination that the interwebz told me has xx compression height and xx head and xx deck height, I will have a perfect cr for my application. The internets also told me that no matter how big the cam is I will never have valve clearance issues. EVAR And the Internet is always right, right? ...If these thoughts are running through your head, you'll be in the same place you are now on build #2

But why do it to such a clean shell?

Yes the larger ones are for the intake. But please do yourself a favor and just use bolts. You'll thank us later and I promise you, you'll not find yourself in need of the extra holding capacity (really the even load spread that a torqued surface experiences when using a finer thread, which isn't loading capacity) for those top intake bolts.

I'm going to call shenanigans on that for a few reasons. 1. I'm about 99% sure that if you tried to push 485whp through that turbo it would just turn into a hot air blower. 2. That downpipe seems to be clocked in the completely wrong direction if you're using a stock L28ET mani. 3. Not a fan of chinese turbo's. 4. That fan looks entirely too small to cool an L unless it's constantly moving. Moving on... Search for "blow through turbo" and I'm sure you'll get plenty of results here. If you were going to stay carbed though, I'd go for at the very least SU's as the square top's that came on 260's sucked. The quickest and easiest route to get a turbo charged Z though, in my opinion is to find a running (ish) ZXT doner car and stuff all the parts in your Z. Also, the Turbo FAQ in the FAQ section will ramp up the learning curve for forced induction

There's obviously too much BMW in the house. Time for a change #1 Mercedes 190E 2.3-16V Evo II with a Turbo M104 3.2... and take the wing off the back so you cant tell it's an Evo... #2 Datsun 510 with the 2.3-16V Cosworth motor (Plus terbeaux) #3 Custom Tube frame mini with a RWD 13B turbo in it. ...#3 is very likely my next car project after the ol' Z is finished.

Oh the joys that come from dealing with the best mentalities in Chicago. Salt of the earth, some of those Chicago folk.

If you get him hooked on cars that's another story entirely. Once he figures out your knowledge of how to do things is there for easy access and that tools and a space to work on cars is a very expensive thing, you will become his best friend again.

Agreed, many people fail to remember that V8 guys can play with turbo's too. It's not like there is a law that makes it illegal for all cars with more than 6 cylinders to have turbo's. Rumor has it that 4 rotors can have turbo's too. But when this rumor was stated, V8 and I6 guys alike quickly killed him before this could be spread. *hides* Something people fail to take into account is bias. So I'm going to tell everyone now that I love I6's. I love how they sound, how the turbo motors deliver power, and how smooth the are. But at any rate I also think both of these motors have reputations far greater than the engines they actually are. No thermodynamic system is perfect, and both of these are exactly that. Let's look at this from a logical standpoint shall we? 1st. Head design. No one is not better than the other. Ported the both flow more or less the same. RB has port floors that are entirely too parallel to the piston/flame front for the kind of RPM's people turn them, IMO. However, a couple of papers toyota and some engineering groups have published have suggested that the pentagonal combustion chamber is a happy medium of flame propogation and detonation resistance. The Pro-stock drag guys have shown that in a GASOLINE engine, the "bathtub" type combustion chamber is quite good at producing efficient engines (why BBC's are still big in pro-stock) while the Hemi design is better suited to alcohol. The LSx heads are nifty things, but to get big numbers required really big numbers porting or aftermarket heads (or ported LS3/L92's?) and still share the head lift problem in very high HP applications that pushed GM to release the Iron LSx block with two extra head studs/cylinder. Also the CC that does so well in efficiency (why LSx's get rediculous mileage for their displacement/power levels) also is not quite as knock resistant as the pentagonal combustion chamber. Because of the cam on bucket design the RB would be better for high RPM's, but the bottom end isn't. We'll get there in a second. Overall: It's a crapshoot really, if anything I'd give a very slight advantage to the LSx heads (yeah, a 2 valve head just beat a 4 valve head, deal with it) due to their efficiency in a street application. The Block: The LSx alloy block is LIGHT. But in high HP applications or very large bore applications, flex can be an issue if pushed enough. If so you'll need to switch to an Iron block which kills the "legendary" LSx weight advantage. The LS does have a deep skirt, 6-bolt main cap design, which is happily shared by it's contemparary Toyota UZ and Nissan VH/VK rivals. (Also the late MB engines, if anyone cares ) The RB block is stiff, having a full cradle in the block which sits in a deep skirt. The block is already Iron and is a pretty stout piece, as stock units are used in racing (as if they have a choice?) and have shown few cooling issues or strength issues. The RB block also includes oil squirters for all those happy hair dryers which love to dine on pistons. Verdict: You decide. Both have their advantages. The crank/rotating assembly: Both have cranks missing counterweights. The LSx is missing them in the standard V8 places, and the RB in the normal 2/5 area. The difference here is that the LSx is meant to be a lower revving motor. This means that the harmonic problems that come into play when spinning a partially counterweighted motor at absurd rev's probably wont be an issue, and will never on a street motor. The RB has a partially counterweighted crank too, though it's known for it's ability to spin crazy numbers on the tach, which means you may get to experience this wonder of partial counterweights. The moral of the story here is that any crankshaft that has a journal and it's corresponding counterweight at least 1 main journal away from it puts stress on that main journal as it has to ballance through it. Not cool. Also, some LS cranks are cast, IIRC all RB's are forged. On a street motor this shouldn't matter but if it does, the RB is covered. Valve Train: This is a double edged sword. From a purley performance standpoint, the cam on bucket direct action of the RB is hard to beat. The belt however needs attention and has fallen out of favor by car companies due to it's propensity to fail (not in RB's particulary, but in all engines). The LSx valve train does not have the ability to adjust exhaust and intake timing individually, and it also has a heavier reciprocating mass with lifters, pushrods, and rockers. However, the LSx recooperates from this with the advantage of being much more compact in head design than the RB. Power Delivery: Big difference you'll see in these motors is how they deliver power. Due to the size of the turbo that you'll need to achieve the equal power level of an LSx motor, you'll see much less power/torque at the bottom end of the rev range and an exponential growth as the turbo spools to the top of the powerband. An LSx will maintain a much lower powerband with it's greater displacement and should be much more linear. To add power NA though would require a cam that would also move the power up in the band. Running a stock cam and adding a turbo the same size as the RB's will allow a powerband lower in the rev range, with more bottom end torque, as the extra displacement (2x+) will happily spool a turbo much more quickly. For a street motor, the ability to pull from a much lower RPM around town is a fantastic thing to have. Driving a full race motor in a mini with a 4-8k powerband is a blast, but going from stoplight to stoplight or in a traffic jam is a PITA. Good reason why I went to a 256 cam in mine. So which is better? Neither. Both engines are good, and both do what they're designed to do. For a site that prides itself on there being not "best", people tend to get rather opinated on the "best" (mightiest, godliest, etc.) engines. So what do you want, a car that has a bunch of bottom end grunt but not as much top end scream in an extended rev range, or that explosive top end with less torque so you have to wind it out to get the power out of it? Odds are that you'll never push each motor to it's fringe limits to really see which design is better. One more thing to remember... You can get LSx parts at autozone. DOUBT you can do that with RB26 parts. Your driving experience. ...wow that was long

Use something non-conductive and amphipathic. Gasoline will not dissolve things that are water based, as they're not miscable. Try some acetone. Then flush with gas.

There probably hasn't been a discussion on efficiency vs. diff simply because stuffing oddball 3rd members into cars isn't exactly a common occurrence in most car circles. THAT SAID: The highest losses should be in a transmission, provided both are equally broken in, as far as I would come to believe. Especially an automatic transmission. It has many secondary systems that draw on engine power to operate. I would have to say that in relation to parasitic losses, the bigger and stronger the transmission, the higher the losses. The larger, wider gears in a bigger tranny has more total contact area on the gears, and thus more friction (given all else equal). Finally, the CF d-shaft should not have any bearing on how well it transmits power (from a total efficiency standpoint) as there is no friction or moving parts on the driveshaft itself. It simply transmits power. The idea of the CF d-shaft is that there is less rotating mass so it can more rapidly change rotating speed than a heavier unit. The part of a d-shaft that would alter efficiency are the U-joints/CV's as they're responsible for changing direction of power, and unless they're 100% friction free (nothing is), there will be a loss of efficiency as the direction of torque is altered.

All projectile projects usually can involve a substantial amount of math/engineering. If you never want to work again, design a bullet that can do a stable and accurate decel through the sound barrier to subsonic without losing trajectory in either the x or y axis. This is the only thing that is keeping rifles at a fixed range as once they enter transonic and then subsonic (roundabouts 1100fps and below) they tend to become very destabilized. I'm very sure the US govt would be more than willing to pay for your retirement. Then again, I made a pneumatic spud cannon that would put a 'tater out 400 yds on 120psi. All good fun.

I wouldn't use studs on the top of the Intake mani, If you do, it's a SOB to get that sucker off of there. I had some on my carb motor and I took them off. It was entirely too much of a pain.

For the slim flow increase you get between a good air filter and an open intake, It's not the cost of sucking all sorts of exciting things into your motor. ...Unless of course you enjoy rebuilding motors much more often. If you've ever seen an air filter after 30k (I'm sure you have), All of that went INTO your motor. ...Tasty.

A C43 AMG????? A little part of me just died. My faith in humanity has fallen. I'll give you 5 grand for a C43, and you don't even have to spend that money buying a new car.

...must....not....want...

There are a couple of V8 Mini drag cars in the UK... I'm not sure who decided to do it first, but god bless him. I personally want to put a tube frame and a rotary under my estate