sc3boost

I was looking at some pics of the lf-a and is350 and they are the only other lexus i would swap my sc300 for.

then i got to thinking, why did toyota swap the 2j for a V6?

i know not everyone wants a turbo or buy a car with performance in mind, but why not a n/a 3.5L inline 6 or a 4.0L I6(3jz) then "to me" toyota will be king of the hill engine wise.

am i missing something? it would actually be great to see another engine put the 2jzgte in the second best cataglory (especially a toyota)

with the come back of camaro,charger,and others a 2008 supraTT or a is400 with 3jzgte(4.0L TT 6 speed manual inline 6 would definatly slow sales of any other performance coupe or 4 door vehicles.

so why v6

LexFather

Packaging. I-6 requires a longer front end and is just harder to fit in a variety of vehicles. The V-6 is more compact and thus can be fit in more vehicles. Toyota is doing this some with their 3.5 but look no further than Nissan, putting it in almost every vehicle it offers. The VQ is a great enough engine to be able to do that.

I-6 does offer smoothness a V-6 can come close to matching.

Also, looking at the new Toyota 3.5, it is now a Wards 10 best engine, with the VQ. So with direct injection and dual VVTi and technology, V-6 have come a LONG way.

Clearly BMW believes in the I-6 and I commend them for that.

Koma

iTrader: (3)

Pretty much explains it all, they're bulky.

DriftNsc3

That would be a beast of an engine. I wonder whats the most some one bored out a 3.0 I6 to?

Koma

iTrader: (3)

Another thing, if they were to produce such cars they would probably have to mate them to RWD drivetrains as placing an I6 longitudinally would make a car one bloated beast. The reason Lexus can make their cars inexpensive is because they share parts and platforms with Toyotas. What RWD Toyota sedan/coupe would sell with a higher price tag? That's a reason why the Supra died, they couldn't reduce costs enough to make them sell.

It works for BMW because they don't make economic vehicles.

DriftNsc3

So according to what you just said, A Lexus is nothing more then an overpriced Toyota? Why can't Lexus make a RWD platform for themselves? I mean they are coming out with the supercar now but why not something to compete with the M3 or SLK or whatever competes with the M3? I understand it cost but I mean the #1 automaker in the world should have some money to throw around some ideas.

lobuxracer

iTrader: (2)

I-6's also more prone to torsional vibration which causes engine control diagnostics to be more challenging. Toyota went through a lot of software challenges for OBDII with the 2JZ because their misfiring algorithm depends on crank acceleration. The length of the 2JZ crank makes this difficult because it tends to wind up and release which makes false misfires common especially in manuals.

The biggest reason I-6 is such a great design from the engineer's perspective is the freedom to design the intake and exhaust geometry without bumping into the car. Unfortunately with the aerodynamic constraints imposed by lower hood lines, those advantages disappear quickly. The GTE head is a perfect example of extreme compromise for packaging and not for performance.

If you look at the picture below, notice the exhaust ports being angled toward center on the GTE head. Also notice the intake ports on the GE head and how much steeper they are than the GTE head. Steeper is VERY desireable. The GTE head compromises both the intake and exhaust for packaging reasons. In a world concerned with high efficiency, low emissions, and high specific output, these kinds of compromises can't survive.

lobuxracer

iTrader: (2)

Biggest overbore for a 2JZ is 1mm. Most guys stroke them for more displacement to about 3.4 liters.

GSteg

iTrader: (15)

lobuxracer beat me to it.

in addition, the crank must be stronger. When made to the same spec, the crank of the V6 is going to be superior to that of the I6, because of the given length and where the force is being applied on the crank.

It's just more feasible to go with a V6.

sc3boost

i guess this is true.

also i don't mean put inline 6's in everything, just keep things the way they've always been (gs, is, supra) the new sc430 to me went a completely different direction than the sc300 so leave it out, or just use it in the supra to keep it exclusive.

a unique thought would be to just change the name of the toyota supra to lexus ??????, maybe that was the thought behind the lfa.
someone told me that the g35 is the new nissan skyline.


i love the I6, kinda like those V8 guys who think if it does'nt have a V8 under the hood it's a rice rocket.

also how can they make a v6,v8,v10 or v12 supra? most people want to stroke there 2jz's to 3.2 or 3.4 so the love for the engine is still there, and anyone i meet that owns a supra wants the same thing more power more torque but they will never put a v8 or v12 under the hood of a supra, even if they can make more power by junking the 2jz.

also if a used 94TT supra goes for $20.000+, by a strech of the imagination a 2008 4.0L I6 TT 450hp(LEXUS)supra will definatly sell for $40000-$50.000+,

SteVTEC

Ford has an Aussie built 4.0L turbocharged Inline-6 in their Austrailian FPV Typhoon F6 sedan. That thing is friggin awesome, but yeah unless you want your hood in the shape of a brick it's not gonna fit. Even BMW has to compromise a lot on design just to fit a 3.0L I-6 in their cars. You can see that their hoodlines are just a bit longer, and they can't cut down at the nose as aggressively either. The Z3/Z4 cars are basically an Inline-6 engine surrounded by a bit of car here and there, LOL.

Volvo does make some transverse FWD Inline-6 cars but they have to go through major packaging pains just to make a 2.8L fit. The Suzuki Verona has a 2.5L transverse I-6 also. If you want flexibility, you need a V-6 which will fit in anything.

sc3boost

read carfully as i am not trying to start a fight but when i think about it, it sounds bad...

if this is true then why not make the original supra with a TTV6?

and also everything being equal do you mean a 3.0l turbo v6 will make more power than a 2jzgte both modded to the same level to make over 1000hp

sc3boost

i'm a glass half full kinda guy, sooooo

now they know what they have to work on to make the engine perfect

GSteg

iTrader: (15)

an inline-6 engine is naturally more balanced than a V6, as some people put it, it's smoother. The vertical and transverse force that's being output by each cylinder will balance each other out. On a V-series engine, you're going to get end-to-end vibration. Manufactors have put on balancer shafts between the cylinder banks to reduce this vibration.
You're also using more camshafts and parts on a V6. Simply put, you're going to have more frictional loss with a V6 than an I6.

lobuxracer

iTrader: (2)

Supras were traditionally inline 6 cars. The 2JZ block is actually a forklift block, so Toyota had considerable practical experience with its strength and durability long before it was installed in a Supra. It's also a high nickel content cast iron, so it's extremely strong (essential because of the length problem) and fortunately for the boost heads, it will tolerate really insane boost levels (closed deck, high nickel cast iron). It is not a light engine though. IMHO, durability under pressure is one of the biggest reasons they chose it for the MkIV Supra.

V configurations require a specific angle between the banks (6's like 60 degrees, 8's like 90), or they need offset individual rod journals on the crank to achieve satisfactory primary balance. Inline engines don't have this issue because the vibration is fundamentally in a single plane. V engines need more complex main journals for this same reason - the forces on the crank are coming from two planes, so vibration will try to push the crank out of the block in two different directions requiring a more stable main bearing support from the block. The V-6 crank is still simpler and cheaper to manufacture.

Inline engines like 6's are also more prone to headgasket failure. The 7MG is a perfect example of this. A V engine's heads are much shorter and can be machined to fit more easily (read cheaper) than a single longer piece. Casting a single longer piece without core shift or other casting faults is harder (read more expensive), and this is true for both block and head.

While it is true, the parts count for a DOHC inline 6 is smaller than the parts count for a DOHC V-6, the other production efficiencies, and the simplicity of grinding a cam half the length of the I-6 cam make it not such a big deal. From a pure friction perspective, it's pretty close to a wash, and again, in the valve train those long cams are more prone to torsional problems (and subsequent valve timing errors) than the shorter cams found in the V-6.

Basic considerations - bore and stroke - are limited on the I-6 for packaging reasons. Bigger bore means longer engine and all the negatives (especially NVH) associated with more length. Longer stroke means taller, so the hood line suffers. With the V-6, you can easily go oversquare (bore greater than stroke) without having to add inches to accomodate the length increase or go undersquare without having to raise the hoodline to accommodate the additional height. With the I-6, these are 1:1 relationships, V-6 <1:1, so packaging wins again.

So, tradition was a big player in why the Supra got the 2JZ. NVH, emissions, specific output, and more than anything, packaging; are why we are seeing mostly V-6s today.

Oh, yeah, there's no way the engine configuration is going to determine how much power can be made. It might affect service life, but 6 cylinders with 3 litres turbocharged is going to make the same power regardless of configuration assuming all other parameters are equal.