theloudroom

If you're going to call "physics" I would like to actually see some. Where's the math?


Where's the list of masses and their radii from the center of the vehicle?


I wouldn't have said anything if you didn't take such an incendiary tone with this guy, but damn. It annoys the crap out of me when someone starts lectureing a guy on "physics" yet they aren't doing any.

"tbielobockie" clearly understand just as much about physics as you. Don't tell someone to "got read up on it" until you've done the same.


Sheesh, I think he's 100% right that polar moment of interia is overhyped. Consider this:
If polar moment of inertia was the key factor, then drifting would actually be FASTER than normal driving. (This is because the car would already be pointed in the right direction to exit the corner.)

Polar moment of inertia isn't a totally useless figure, but some people value it much too highly.

Try calculating the work needed to rotate a car 90 degrees vs. the amount of work to turn a car 90 degrees at 60 mph, and you'll see. (For simplicity assume that the car weighs 1000 kg, has uniform weight distribution, and both actions take place in 2 seconds.)

If you can't do that:
"You might try to read up on it."

projekt

except for the fact that it loses a huge amount of speed driving sideways....

Dyre

All things equal, a car with weight distro focused towards good polar moment will handle better than one without. Therefore a motor swaped (be it V8/I6/20b) RX-7 will always be at an initial disadvantage to a RX-7 retaining the 13b/12a. Thats my point.

Im not trying to say its going to be a huge difference that is going to make the car unable to turn, but fundamentally it shows you can't say the V8 weight distrobution will be exactly like the stock car. Thats the only point Im trying to make here.

The alluminum pushrod 16v V8 is still the best swap canidate though, as the majority of the weight is still down low in the engine bay. Hell, I just ordered my wiring harness and motor/tranny mounts today for the LS1 so I'm not bashing the swap at all. Im just saying its going to be diffferent.

digitalsolo

iTrader: (2)

You're making a good point. A lot of people over-analyze and tear statements apart too much. What you said just there is dead on. Now, obviously, with work, the polar moment can be moved back to (and probably placed better then) stock (which I know you didn't argue with) What are you swapping the LS1 into? FC? FD?

tbielobockie

In the back where BMW puts it.

tbielobockie

It's total and complete garbage and you and all of the little rotards crawl right up to that Mazda marketing nipple and suck away.

The bulk of the LS1 engine is actually lower in the chassis rotary engine. The fact that 50 or so pounds of weight is a few inches higher and more forward is totally meaningless in the big picture.

The big picture is simply this; 100lbs is a mere 3% of the total car's weight. Moving 50-75-100lbs 6 inches is going to have zero effect on the overall handling of the car. None. However the vastly superior modern piston engine's wider torque curve and instant throttle response will have a dramatic impact on the overall feel and handling of the car. To justify your senseless position you're finding the most insignificant non-problem and making it large while trying to minimise those things that actually matter.

My point which is quickly eluded you is that if Mazda really gave two ***** about overall handling and it wasn't just marketing bullshit they would have put the battery somewhere else. Rather they put it in the worst possible place from a handling perspective.

Lastly you're basic problem is this. Denial. You've swallowed a whole load of bullshit; that there is actually any advantage whatsoever to rotary power (which there is not). You can't quite come to terms with the fact that you've been snookered and this basic core belief is utter and complete non-sense. When the denial wears off, reality will set in. It'll hurt a little at first, but then you'll be the better for it.

projekt

adds weight to the car, removes even more trunk space, more difficult to work on.

projekt

so at 165lbs you're telling me that i won't notice gaining 5 lbs?

tell that to a woman who's chest goes up a cup size or two when they get pregnant.

Dyre

Wow, who pee'd in your ******* cherrios?

The LS1 is going into a FC (S4 TII)-

If engine placement didnt matter griggs and maximum motorsports wouldn't create insanly complicated k-members that move the engine down and back 1 inch. If it didn't make the difference why would then bother? Why does every single tube frame race car put the engine as far back as possiable?

You can't simply say it doesn't matter becuase it ******* does. How much? thats debateable like most thing, but it is still something to concider.

Engine placement and location is one of the reasons the supra power FD is one of the stupidest swaps ever concieved-

projekt

I was under the assumption that it was MaD tYtE Yo!

Dyre

Hahah yeah. shifts mad quick too-

turbojeff

iTrader: (30)

A 2700 lb FD with a LS1, ac, PS? That is a lot less than the 2960lb LS1 FD I weighed today.

I call BS on a effectively "stock" FD with a LS1 that weighs in a 2700lbs.

thant

I have a supercharger and an intercooler on mine and it weighs 2875 on Longacre scales (no A/C). Was it an automatic? You guys should probably go to a scale that is a bit more effective at measuring things other than 70,000 pound trucks. Iwould guess you weigh around 2825, unless you have a lot of extra stuff in the car, and heavy wheels. My R1 cym with an FMIC and light wheels exhaust and no extras weighs in at 2595 which is pretty light.

turbojeff

iTrader: (30)

My 93 R1 weighed 2796lbs on SCCA scales at a national tour event. The same truck scale weighs it at 2800lbs. I'd say that is good enough.

That was with a full tank of fuel. I forgot if the tank holds 16 or 21 gal, gas weighs 6lb/gal so figure that a tank of gas is somewhere between 96-126lbs (full to empty comparison) so fuel can make a large difference.

Another thing, the LS1 car was a 94 Touring. A 94 Touring in front of me with the EXACT same mods my R1 has at the SCCA event weighed in at 2900lbs and he was down a few gallons of gas. 94 Tourings are probably the heaviest of all FDs with manual trannies.

BLKTOPTRVL

I thought the older Corvette engines produced more like 300 - 350 HP, Don't the newest ones produce 400HP?

Dyre

The best older vette's are LT1 cars making probably 280-320bhp depending on the yea (i think they made 320 in the latter years???). New vettes make about 350bhp (excludes of course ZR1/Z06)

Ph00ny

how much increase in weight will there be if you bored out the ls1/6 to 400ci? What about c5r block swap to ls1?

wingsfan

Well, you can't just bore out an ls1 block. They come from the factory with a bore depth of 3.900", and can only be punched to 3.905".

To get increased displacement you can increase the crank to 4" which would get you 382. Or you could run an iron lq9 block, but I'd imagine that it's at least 100 lbs heavier. Or you can get the ls1 block resleeved and then bored up to 4.155 (4.125 with a 4.00 inch stroke is 427CID).

The resleeving wouldn't increase the weight by much. Whatever the increased weight of the crank and new rods would be my guess.

I have no idea what the weight of the c5r block is, but it too is all aluminum and fits in the LSx footprint, so it probably isn't too much heavier. Of course, why anyone would buy one for $6K when you can buy a Darton reseleeved block from Jim Hall, MTI, or Lingenfelter for half of that, I don't know.

Ph00ny

isn't c5r block nothing but a bored ls1/6 block? As for the 400ci, that was just a random figure that i pulled out of my ***

wingsfan

No, it's similar, but has enough differences to be considered it's own thing. It's designed around the 4.120" cylinders, and has some reenforced cylinder walls and different oiling/coolant passages. In the C5Rs it's set up for dry sump oiling as well (99% sure). Maybe Jimlab will chime in at some point as I'm sure he knows more about it than me.

Katech makes a block from the same casting that's been machined for wet sump use, but it's $6000.

http://www.katechengines.com

Check out their 7.0L race case. I looked at it for awhile whne I started my LS1 conversion, but A) it's expensive, b) it's likely complete overkill, and C) did I mention it's expensive? I spent enough on my conversion as it is, I didn't need to add another $10K on top of it.

jimlab

Katech manufactures the 7.0 liter (427) C5-R block for GM, which is a totally different casting from either the LS1 or LS6 blocks (which are separate castings also), as wingsfan said.

The LS1 and LS6 blocks are already sleeved from the factory, so to get 422 CID for their Z07 conversion, MTI bores out the OEM sleeves and then new larger sleeves are heated and pressed into place. There was an interesting article on their build-up of a 427 in the March issue of GM High-Tech Performance which showed the process. Aluminum LS1s up to 454 CID have been produced, but they're based off the Katech casting. The 6.0 liter iron blocks are also used by some for getting more displacement, but with an obvious weight penalty.

The weight increase of a stroked engine is marginal and usually can be attributed solely to the crankshaft. Forged rods and pistons will usually weigh a little more than their stock counterparts, but forged crankshafts are heavier than cast crankshafts anyway, and the increase in stroke adds a few pounds too. However, there are lightened crankshafts available, and for extreme weight savings, custom superlight billet crankshafts.

jimlab

Corvette LT1/LT4
1992-1996 LT1 - 300 hp
1996 LT4 - 330 hp

Corvette LS1/LS6
1997-2000 LS1 - 345 hp
2001-2004 LS1 - 350 hp
2001 LS6 - 385 hp
2002-2004 LS6 - 405 hp

Corvette LS2
2005+ LS2 - 400 hp

Ph00ny

nevermind. I was always under the impression that c5r block was nothing but a bored out ls6 with reinforced cylinder walls.

fc3sls1

MY 89 FC with the LS1 weighed in at 2643lbs with a full tank of gas. I plan to get it down to 2600lbs. My engine made 540hp at the crank which equates to about 430 whp on a mustang dyno. The car ran a 11.9 @ 124 mph on burnt azenis with a 1.96 60 foot. The car handles like snot!

wickedrx7

iTrader: (14)

Do you realize this thread is from 2004?