DDSLT5

Hey Bob,

I'm not talking about wheelspin and yes, by dwell I mean time in gear. I've got 4.10s in my 402 and I run DRs all the time in that particular ride. She is a bitch to hook up without them. The car feels fast - it feels like my 415, but when you run them side by side, the 415 just walks away, even with the advantage of the gear. It takes time to shift and I don't power shift my ZFs, so any advantage of the gear gets eaten up pretty quickly.

I think the 4.10 gear for this car is a good thing, but let's not blow too much sunshine up each other's respective rear ends - Rick's car with big cubes is gonna show every stock cube motored ZR-1 his tail lights. More torque, more hp, and less weight. There is no need to talk about gears because Rick has the same rear end as a ZR-1 - he can throw in 4.10s just as easily as anyone else, but regardless, there isn't a gear on earth that can negate a 100 rwtq disadvantage.

Aurora40

It seems silly to get into this, as I don't think you really care about the math.

But a car that has a 7,500 rpm limit can run more rear gear than a car with a 6,000 rpm limit, and have the same "dwell time", as you put it, because both cars will run through the same mph window per gear. The extra gearing will increase the wheel torque available from the higher revving car, possibly enough to negate any engine torque advantage, and possibly not.

I'm not sure how no gear on earth can address a torque difference. Torque can be multiplied by gearing. It's power that can't.

But really, this wasn't even my point. My point is the LT5 seems to be getting easier and cheaper to make bigger power from than in the past. It's becoming more practical/cost effective to mod a ZR-1 to a certain power level than an SBC C4.

DDSLT5

You're talking about a 1000 rpm difference, IF you've bumped the redline on your LT5 up from 7072 rpm to 7500 rpm, which you likely haven't. Rick's redline is 6500 rpm, thus giving only a little bit more rpms to run up.

Now if you can either use an infinite number of gears, or rev infinitely, then yes, 4.10s will be a huge advantage. But in the real world, it's about power, not gears.

"Torque can be multiplied by gearing. It's power that can't."

That statement is nonsensical. Hp is a value calculated from torque.

As for modding the ZR-1 - did you read any of my other posts? It 'may' be cheaper to mod it, but how many shade tree mechanics are going to pull their own heads and port them themselves? If you want any level of real power, you need to pull the heads - and this is likely going to be done by a tuner - and that costs money.

I find it is always those who haven't done any major mods to their ZR-1 that continually bleat about how cheap and easy it is to mod them. Go ahead and embark on getting 500 rwhp from your LT5. Let me know how cheap and easy it was in a few years when you're done.

zr-1 guy

is it easier and cheaper then it was in 1999, maybe
is it easy or cheap? no, and it never will be. I ran the numbers and for topend/heads/pc/other small mods the bill was $13,000...the poring alone was nearly $10,000. If you want cheap speed buy a foxbody mustang.

Have you priced stroker cranks? you're looking at north of $2,000 for the the crank.

FastMatt2

It's easier and cheaper to build a LS motor car yes, or allot of other cars for that mater. I can take a stock stealth or 3000gt and put less then 4 grand in mods into in and run 10's on normal street tires. That does not change the fact that the LT5 is a really cool motor and the C4 ZR1's are cool cars that hold a place in my hart. I would LOVE to have a 441 in my ZR1, to the point that I was thinking very hard about buying FU's car and pulling the 441 and putting it in my 94 AB car. I would much rather have a 441 C4 ZR1 then a 600+hp heads/cam C6 Zo6 thats for sure.

glass slipper

Torque is nothing without RPM and only the slow witted would ignore HP. If you want torque, a Duramax Diesel is easily modded for way more area under the torque curve than your 415 or the LS7...so when is the engine swap happening???


HP is measured first on a Dynojet chassis dyno and then torque is calculated...so now what?

"Torque can be multiplied by gearing. It's power that can't."

That statement is the 1st Law of Thermodynamics stated very eloquently and obvious to anybody with any engineering sense. I can see how it might seem "nonsensical" to a dentist.

Bottom line...it's about HP, the area under the HP curve in the RPM band used during a race, and who can get to that RPM band first. The fact is that gears let you get into your powerband quicker. That's why a car with 4.10 gears is quicker in the 1/4 mile than the same exact car with 3.45 gears.

95ZR1

Hey Hey

DDSLT5

Nice to hear from you 'glass slipper'. Here's a concept that seems to have escaped you in those heavy years of education at PS #23:



Horsepower = Torque * RPM/5252




and consequently:




Torque = Horsepower * 5252/RPM




Torque is the tendency of a force to cause or change rotational motion of a body. Torque is calculated by multiplying Force and distance, so the SI units of torque are newton-meters, or N*m (even though this is the same as joules, torque isn't work or energy, so should just be newton-meters).

Or:

1. The moment of a force; the measure of a force's tendency to produce torsion and rotation about an axis, equal to the vector product of the radius vector from the axis of rotation to the point of application of the force and the force vector.
2. A turning or twisting force.

Power (or horsepower) is just another expression of torque which takes into consideration the rpms (or the speed) of the flywheel. Bottom line: the more torque you have AT ALL RPMS, the better you will be able to motivate your vehicle. If you can hold the exact same amount of torque over the whole power curve (like an LT5) then it is best to keep the motor at the operating range at the top of the curve as this delivers the most torque to the wheels. The slow witted will now argue that horsepower is better - however, if you would simply look at the calculation used to derive a hp number, you'll understand that it is simply an expression of how torque relates to rpms.

With a well matched transmission and a peaky motor, you can go very fast, and take advantage of lots of high rpm torque, even if you lack torque down low. This is the idea behind a high reving small displacement motor.

Having said all that......and my point from the beginning, Rick has lots of torque over the ENTIRE curve - at low AND high rpms. His car will plant you in the seat whether you hit the go pedal from 2500 rpm or 5000 rpm! That's the advantage of cubic inches and an intake that can feed enough air at high rpms. This gives a car that can go like hell and be very punchy around town and not require you to rev the **** out of it to be fun.

As far as "getting into the powerband quicker" that only matters from a dead stop. Otherwise it is simply a matter of shifting into the right gear, get the rpms up and hit the throttle. For the 1/4 mile, if you actually go to a dragstrip you'll see that 3.45 geared ZR-1s et and trap VERY close to the 4.10 geared ZR-1s. One less shift means time saved for the 3.45 geared car. As always, it is about the launch.

Personally - I couldn't care less about the 1/4 mile. I am more interested in road racing or open track racing. 4.10s definitely make a ZR-1 more fun around town, which is nice. However - if you guys with stock cubes run into Rick or a C6 Z06, you would be wise to keep her in 6th as both cars are going to open up a big can of wup *** on you. Sorry - just the way it is!

DDSLT5

Hey Ted - don't you know that if you lack any creativity it is prudent to resort to insulting the other guy's profession? Keyboard commando at his finest!

Paul Workman

We're a loooong way from X-pipes by now. So, I'll preface this by saying that a local FBI guy, "Al" on the Registry, worked with SW on their X-pipe design. According to Al, the X-pipe was worth...he says...20+ hp, but that might have been on a big cube LT5.

The hp/torque debate...It never ends. OK, my tip-in point (so as not to appear too "ignert"...)

HP=torque (ft#) x RPM / 5252

There was a great article by Lingenfelter showing how rw torque affects acceleration in the quarter mile. Coming as no surprise to anybody with high school physics, acceleration is directly proportional to force applied at the rear wheels...duh! And, the article showed to no surprise, the greater the average RW torque, the quicker the car was in the quarter. A higher rear end ratio results in torque multiplication, but in shorter spurts (power remains constant, so RPM of the rear wheels suffers in exchange for torque). The trick is overcoming the lag resulting from having to shift one more time in the quarter - ending in 4th, when using a 4.10 gear, as opposed to staying in 3rd all the way. If you can overcome the gear shift, 1/4 mile times are improved, according to the article, due to a higher average RW torque.

It's all pretty elementary, actually. It boils down to where you want to concentrate the effect of the power provided by the engine (which doesn't give a hoot what the rear gear is - it puts out what it is going to put out). With gearing, engine output can be concentrated in the low speed zone for acceleration, or spread out in favor of speed. The 6-speed transmission is a way to have both!

Does that make any sense?

P.

DRM500RUBYZR-1

"Does that make any sense?"

Actually; Yes it does. Even to a banker. You have all scattered some diamonds of knowledge on the floor. However, many of them are obscured by the yellow fluid flying in their midst.

I ask again.....

Is the described X-pipe available new from any source, that matches up to the B&B 3" system?
Anybody???

OK, you may now resume the physics lessons, although footnotes and references will now be required.

Good Stuff.... I guess that is why Rippie went with the 3.73 gears in mine. Either he had it figured out, or couldn't make up his mind either.
The cams also feel as if thye have introduced more torque earlier than in my first ZR-1. But, these are fascinating motors when they really begin to come online.


Marty
1FUNZR1

Aurora40

These are formulas for engine torque and horsepower. I can only assure you that the torque at your rear wheels is different through each subsequent gear shift. I would think real life would have illustrated that to you already.

This is getting even sillier. I guess you can accept it or you can argue it. I didn't invent physics, so I'm not overly offended if you don't buy it.

Aurora40

Haibeck will port heads and your intake for $7k. Heads only are $5k. Not cheap, but Marc's goal isn't to be a discount shop either, nor does he need to be.

People are always guarded about their costs, but some of the "FBI" heads ported and/or the regrinds, are those guys spending $10-13k on engine work? It didn't sound like it, but I haven't seen any real numbers.

Certainly strokers get a lot pricier. Which is why I mentioned stock-cube cars.

How much do you think Rick's 421 cost him? I suspect he'll be guarded about the costs too, but I would be surprised if it was under $10k, not to mention the time aspect and I believe he's mentioned he's still working on the tune.

Which was my point. A stock cube Z can put down similar power to a big-cube SBC in a C4, for what seems to be similar cost. Which one is easier to tune, drive, or to get through emissions? Which one would have the higher resale if you had to get rid of it?

The Z argument seems to be getting better compared to the L98/LT1/4, though obviously it is not the cheapest car out there to modify and, as you say, never will be.

But maybe I'm the only guy that thinks so.

Aurora40

Ehh, the thread is 9 years old...

You might already know, but I don't believe the shift is as costly in time-to-distance measurements as it is in time-to-speed. In terms of covering the 1/4 mile, when you make that final shift, you are still travelling at around 80mph or so. So the time during the shift while no acceleration is happening still results in you covering distance. It obviously has some effect as the car is not continuing to accelerate, but the effect is smaller than like a 0.3 second shift time would suggest.

In like 0-60, the time spent shifting would directly add to the time to speed.

Dominic Sorresso

glassslipper,

To your point on gearing, myself and Lgaff could provide an unscientific example. We lined up several times with our 92s. Both ported top end, both w Watson headers. Lee was consistently quicker on the 60' and 1-2mph faster at the 1/8. 1/4 mile times were .3-.4 faster altho final trap speeds could be as close as .01mph. Lee has 4.10s, and I had 3.45s.

ScottC95ZR1

Both B&B and Stainless Works sell them.

zr-1 guy

I love my zr-1, but I'd rather mod another car

Graybeard ZR1

Or, if you don't need stainless, Dr. Gas has one cheaper. Works for me.

BTW, the sound of an LT5 with an X pipe and the mufflers pulled is piercing, and wicked loud.

88BlackZ-51

Good info and thanks. Much better then Bob's jibber, jabber....

DDSLT5

Hey Marty - I've got 3.73s in my 415 - love 'em!!!

I just had the fun of driving a bone stock 90 Z. Car is a time machine!!!


Conclusion: this car BEGS for some 4.10s! It takes soooo long to get into the power band in 1st - wow - did my car ever feel like this?