Belloc

Can someone please speculate on why GM would resist putting FI into the C6? Seems they are looking at bigger displacement and 3 valves when a simple turbo/supercharger would give them all the horsepower they could dream of.

drew priest

I think there are several different reasons

1 - Weight, adding FI will add weight and add it up top which increases load transfer and decrease the c6's ability to corner, an important consideration for the Z06

2 - Cost, FI is expensive to build and requires major upgrades to internal components in order to prevent fatigue and the expected boost control mod

3 - Throttle response/ performance, this applies more specifically to turbo systems, in that they tend to lose low end torque, throttle response (turbo lag) isnt nearly as bad as it was years ago but turbos still have a very different feel than NA.

3-valve system (IF it is used) will probably be only somewhat cheaper than FI, performance down low is not necessary such a huge deal cause "...horsepower sells cars", so it might be down to the fact that FI just weighs more, yeah it would be descent in a straight line but isnt the Z06 all about the road course?

drew

LittleBoyBlu99

:iagree: :yesnod: :seeya

night feeder

:iagree:

Belloc

Just seems like a factory LS motor with low compression set up for a turbo and/or supercharger would get the enthusiast crowd more interested. I just think it sucks to these Supras putting out crazy numbers with stock blocks.

painrace2

Going dry sump would help lower the engine weight in the car and chassis adjustments could be made to balance the weight.

Scissors

What Drew Priest said.

Plus, I'd rather have 500 HP that I can actually choose how to mod, rather than 500 FI HP that I would have to pay more for up front in addition to paying more to mod.

It seems pretty stupid to force people to accept a specific form of induction, especially a group as devoted to modifying their cars as we are.

Who here wants to pay an extra $5,000 for a supercharger, only to have to go through the trouble of ripping it off to put on twin turbos?

Scissors

Dry sump would lower the center of gravity, but it would increase the car's weight due to added components and more oil.

For good handling, you want to remove as much weight from the front end as possible.

drew priest

Dry sump would also require redesigning/retooling the frame to accomodate the oil, remember hydroformed frame? That would be VERY expensive.
Also for those supra's making 'crazy numbers', my immediate response would be that hp is really not a very good indicator of vehicle performance, torque is a better number to look at, it has a more direct interpretation of acceleration, and unless all thats demanded of the car is drag racing peak torque really isnt a particularly 'useful' number either. What is more important is the area under the torque curve, especially for a road course. Even though taking the area under the torque (also called the integral of torque) is in units of power (hp) this area and hp ratings are very different, if you dont believe me I can write the mathmatical proof, :) But back to my point
hp is a nearly irrelevant number
peak torque is only useful in drag racing
road racing is generally all about the area under the torque curve
the Z06 is generally all about the road course

Drew

ZF Six

Becuase they aren"t FORD!!

Belloc

http://autos.msn.com/research/vip/sp...c=vip#eng_tran

2004 Dodge Ram 3500
5.9L 305 hp I6
Horsepower 305 @ 2900 RPM
Torque (lb-ft) 555 @ 1400 RPM

So this engine would be better than an LS6 for drag racing? Don't think so. Horsepower is king. Your engine is into the higher RPMs almost immediately, of course a flatter torque curve at the top is nice but horsepower is king.

drew priest

I agree, that engine would be horrible for drag racing.. why? because of its lack of hp, no, because it lacks the rpm range to effectively put the torque to the ground, the driver would spend all day shifting to stay underneath its 3000rpm redline, there is a reason why tractor trailers have over 16 gears even with around 2000lbs_ft, yes 2000lbs_ft. (from what I've seen they are only limited by fuel economy and transmission wear)
Let me put it another way, if what you say is true and hp is king then why dont we all drive around in modified turboprop engines. They easily achieve over 1000hp, are extraordinarily efficient, have screaming 25-30k rpm limits, would be nearly just as cheap to build as a piston engine, they are light weight, compact, and are simpler/more durable than thier piston engine couterparts.
why dont we drive around with turbine engines, cause they dont have enough torque to move a tonka.
Im sure you've seen the jet engine buses, trucks, cars, whatever at the shows at drag strips, those beasts throw staggering hp numbers, the numbers get so big it becomes easier to use lbs of thrust instead, but guess what, top fuelers still post faster 1/4 times.
The other problem with that engine is its way too heavy, detroit diesels wiegh near 2,500lbs, about as much a small car, and Im sure that dodges' diesel would do a fine job of tipping the scales. Which makes your comparison a bit unfair, maybe I should have said all things being equal to simplify the model but I just assumed that was implied.

so why does the ls6 win
1 broader tq range
2 lighter
3 its a chevy :D

I hope this explains it a little better.
Drew

Ps why is tq an easier number to understand? cause I can convert it directly into acceleration
(engine tq*trans ratio*diff ratio)/(mass of vehicle*tire radius)=acceleration.

NocarbutaVetteforme

Well then you can tell that to the Ford guys who are simply making a few mods and kicking our butts. Granted it would add more weight but who wouldnt rather have a well built bottom end that can handle tons of HP from the factory? Then we would be the one making the pulley swaps or upgraded turboes and kicking butt and taking names. How many of us have had to bebuild our bottom ends to be able to handle the extra HP and if you didnt then you paid the price. Also, it would be nice to have that factory warranty. Who on here can deny that FORD hit a homerun with that SC much less the KB potential. IF it were and option from the factory then so much the better. AND I agree about the performance of the Supra but once again it comes from the bottom end being built so well. Thats why they can upgrade so much and produce those HP monsters. Now for those who dont intend to mod or anything, then the bottom end and no increase in weight is perfect but for the modding afficionado then we would gladly welcome the built bottom end.

sep1234

Actually, torque is not an easier number. Engine torque is not the same as transmission output torque; whereas, engine HP is the same as transmission output HP (minus the losses -- which are not accounted for in your equation anyway). Engine torque alone means nothing, because you need to know the transmission and rear end gear ratios and tire radius. However, engine power does not require a gear ratio multiplication. It is better to create engine torque at a higher RPM, because you can take advantage of the gearing which multiplies the engine torque. There is another simple equation that gives acceleration: Power / (Speed * Mass) = Acceleration, which derives from Power = Force * Speed. I have heard so many people talk about torque, because they derive some equation with torque and force pops out. Well, you can get force to pop out of a power equation too. In the end, it really does not matter what you use. You just have to remember to state the engine RPM along with torque; whereas, engine power does not need to be stated at a particular RPM. Last year I wrote an article for LS1.com users in PDF format explaining the difference between torque and power. If somebody is interested in reading it, I will post it.