COSPEED2

iTrader: (7)

The main problem is comparing engines alone.

TransAm

Forget about the other cars for a sec.Do you have any possible explanation as to why that Trans Am "Freight train" loses to everything including a 5.3L Turbo 3rd gen making slightly less HP? Are you saying its most likely gearing?

TransAm

Lets be fair, I Showed GTR's Supras, vettes Etc. yes, weight,gearing etc are all Variables. but if you are building two identical cars except motor sizes and when I say identical.... I mean same car making the same Power. then gearing will not stay the same, the one with the smaller motor would TYPICALLY require a tighter Final drive. And a smaller A/r on the Turbo. so to be fair, they would never really be identical.

Now with that said. Shouldn't the output difference be obvious in the cars' performance? I will ask another way:

1krwhp 408TT
Versus
1krwhp 5.3L or 2jz or whatever (geared properly)

Would you expect the latter to win or lose in most races?

HioSSilver

iTrader: (8)

You're a very good example of what op is saying. Check the sig......we had the same 60' too.


Not that I agree with op. But there seems to be alot of under performing larger engines. This is why I tell guys there is no reason for internal mods on LS cars until they get well into the 11's.

RPM WS6

iTrader: (3)

I don't know all the details about every car in question. There is more to this than just the displacement. Drivetrain, chassis and even tuning will play a role....it's about the overall setup and how well optimized each car is respective to its setup.

I agree. This is why I've been careful to state "equally well optimized for the respective setup". Optimal gearing/stall speed/etc. will likely not be the same for two different engines, so it's not so much about the specific items in this area but more about how well matched they are to the engine they are supporting. A max effort small displacement car could certainly be quicker than a nicely built larger cube engine in a comparable car that is otherwise not optimized respective to it's setup.

There is also the matter of optimizing each respective engine; "lazy" vs. "max effort" in this category as well, plus all points inbetween. If the smaller cubed engine is a more aggressive build with a window of higher power/torque (as compared to a less aggressive bigger cube version), and then the rest of the drivetrain is optimized to keep that smaller cubed, hotter engine in that specific window, then I would expect it to be faster.

Again, lots of factors to look at here.

"MAC"

iTrader: (1)

Lol are you serious? Look at the power to weight ratios that is a huge factor then the next biggest factor imo is gearing and then the set up over all. If a tt 408 or any big block thats properly built (key word properly built) should make 1k plus hp n trq. Im not dissing the 2JZ but i promise you it will never be able to match what a 572, 632, 454, hell even a 408 can make when properly built more cubes means more power you can make. That 2JZ can make stupid power and last for what it is. The major advantage it also has over the bigger engines is less rotational mass ( im assuming because it would use a shorter crank and cams, please correct me if im wrong) which helps a lot. But you can have all the power in the world but if its not built right or hooking up you will lose

TransAm

RPMWS6. I think you are right, it makes sense. but why is it most of these guys dont optimize their setups? clearly Im not the only one that noticed, there is a guy in this thread that said the same thing. Im currently still not sure what motor to get for my build. I would hate to be one of "those" guys.



You really should have waited for page two to comment, we kinda touched on that already, but just so you know. the crank,six rods/pistons in a 2jz are heavier than the 8 in an LS motor. and the crank is also a lot longer. its not a v6, its an Inline 6. there is more rotating weight in a 2jz than an LS.

COSPEED2

iTrader: (7)

I understand what you are trying to say, but like a few others, I do not fully agree with it. There are good and bad combos all around and quite a few mismatched and thrown together builds too.

That is why there are professionals though. To help weed out the weak points and issues you may have. If you spend a chunk on an engine you should very well get your moneys worth...but that works in the opposite direction also...quite often you get what you pay for.

TransAm

I posted this on a Supra board and got a reply I am content with..

You need to consider several things. Your only taking into consideration the HP which is estimate. Remember almost every dyno will read slightly different. Some dynos read completely different and others that are calibrated manually can be WAY off. A dyno is a tool to measure progress from a tune and was never intended to measure ***** size.

Aside form that, again power band is another huge factor, as well as aerodynamics, weight of the vehicle and the gear ratios in the rear. Just because its the same trans does not mean that it has the same rear end. Even tires need to be considered as something with a larger contact patch and softer compound will have a inherently higher drag coefficient than say a full pressurized street tire. Far too many variable to consider. All else aside though, if they were the same crank power and same power band/gear/aero/weight etc there would be no difference. One car has a clear underlying advantage in the situation your expressing."

COSPEED2

iTrader: (7)

That seems to be a summation of alot explained on here.

Plus I dont see a huge amount of Supras pulling a 1.4 60'.

Z Fury

iTrader: (1)

Tons of reasons why, really. Budget is a big reason. I've read about a lot of people that blow their stock block, buy a 408 block, and transfer their LS1 parts over to the 408 just to get the car back on the road. A 408 LQx with an LS1 intake/heads/etc. is not going to move very well. At the same time, just because their budget doesn't allow them to "finish" their build, they still want to run what they've got.

This comparison would be a lot easier to analyze if the only people that raced were the ones with perfectly optimized setups. Unfortunately, we don't live in that world. So you get a lot of partial builds running out there making the big cubes look bad - people who are building toward a forced induction/nitrous build but only have the low compression heads/cam/pistons in the block currently, etc.

RPM WS6

iTrader: (3)

To fully "optimized" a setup for a specific type of racing usually means that it will be very non-optimal for other purposes. I think a lot of guys are looking for setups that can be good at several things rather than great at one thing and poor at everything else. And then there is also budget.

MPG and octane requirements, ride quality, off-idle acceleration, general streetability, longevity of components, intended range of operating conditions, available cash, etc., are all reasons why someone may not want a "max effort" build for a given application. Larger displacement often makes an engine more fun to drive on the street at typical street rpm ranges, but depending on the degree to which the engine (and rest of the car) is optimized for racing, it may or may not make it faster at the track. Conversely, the faster car at the track may or may not be more fun to drive on the street (and much of that is personal preference as well).

Dynospeed

iTrader: (3)

Find a 408-427 with a set of all pro heads or something along the same line with enough turbo exhaust housing and wheel flow. It will be a monster as long as the rt of the car is setup correctly. But someone that knows how to setup the motor and turbo efficiently will probably have there chassis in line also. If your running marginal to good heads the smaller cubes will shine. Big cubes need a large bore to feed them along with stellar heads and then enough turbo to keep it all efficient. This is why a 370 works so well for alot of people because a set of afr or trickflow heads can feed them very well. It's about the system as a whole not any peice or 2.

HI-BOOST

Acceleration is all based on your setup. On turbo applications the more lag you have the slower your acceleration will be. I do not see your statement or observation being true on a properly setup vehicle.