TAS09: Re-Amemiya Genki 7... the ultimate RX-7?

[Nico Flax]

Shouldn't that be Mugen is to Honda as Mazdaspeed is to Mazda. Could have picked a better choice then 'Mugen' in my mind. I know I'm picking...

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[kevpotts]

i take dumps that are closer to the ultimate rx7 than that thing is

[Chiketkd]

Originally Posted by dclin

Having said that, what I never hear about is how swapping in an LSx effects center of gravity.

+1 I'm sure CoG is impacted negatively with the swap. One other trait rotary powered RX-7's & RX-8's share is a low polar moment of inertia. The LSx engines are longer and will also impact this -vely as well.

[dclin]

Originally Posted by jigga

are you sure? From what I read, the LSX motors are very lightweight for their size, even being lighter than some 4 bangers out there?

As I said before, a LSx is lighter than most people think, but the only way to get it close to the 50/50 rotary it replaced is by ditching the power steering, A/C, etc. This is talking about the 13b-REW Twin Turbo ; the Renesis NA is no doubt lighter . The turbos and cast iron manifold of the 13B-REW are freaking heavy; my RX7 sits higher about 1/2" on one side after I swapped out to a medium sized single turbo with SS manifold (and ditched the air pump, which probably weighs 30lbs by itself, etc) .

Ditching A/C, PS, etc, is not a big deal if your building a race car, but not compromises I'd make for one that I'd drive on the street.

In Daishi00's defense, what absolutely is ignored or missed by LSx conversion advocates is that, even if you get near 50/50 with mods as described, I seriously, seriously doubt the center of gravity is the same.

And there is more to a well handling car than 50/50 balance. Besides center gravity, how the mass of the car is packaged is something that will affect handling. No matter what you do to achieve 50/50, the LSx would still shift more mass to one extreme of the car (the front), and any compromises to balance this out may mean adding weight to the other extreme.

The beauty of the compact rotary allows the car designer to place it very low and back, allowing mass to be more central. Of course, the LSx makes a heck lot more torque and hp, but we're talking handling here.

[dclin]

Originally Posted by Chiketkd

+1 I'm sure CoG is impacted negatively with the swap. One other trait rotary powered RX-7's & RX-8's share is a low polar moment of inertia. The LSx engines are longer and will also impact this -vely as well.

You summed it up in three sentences. I can get long winded at times.

[Skunkers]

The other thing is this is RE Amemiya we're talking about here. The God of rotary tuners. I'm as big an LSx swap advocate as anyone, but no LS-swap RX-7 will ever have a chance of being remotely as well tuned as an RE Amemiya shop car. Ever. Yeah, the body may look a bit ugly and excessive, but I guarentee every single person calling "FAIL" on that has never, and probably will never, own a car that's as fast around a track as that car.

[Brody8877]

you guys are retarded

[WhiteKnightSTi]

Originally Posted by Brody8877

you guys are retarded

You should learn to use proper capitalization and punctuation before you start calling people retards.

[BurtonCR]

Don't knock the swap until you have driven one. I guarantee you will sing a different tune after that drive.

Additionally to quote some you should know if you are on RX7Club:

Originally Posted by jimlab

Were you aware that only about 80 lbs. of a 460 lb. LS1 is above the camshaft centerline? Were you aware that the heaviest section of the block and the heaviest components of the engine are at the bottom of the block? Were you aware that at any given time, roughly half of the weight of the engine's rotating assembly is below the centerline of the crankshaft? Now, where is the CoG of an LS1?

[BurtonCR]

Actually heres a better quote:
http://www.rx7club.com/showpost.php?...2&postcount=24

Originally Posted by jimlab

Really? Have you measured?

I hate to break it to you, but V8s sit lower (at least in an FD) than the rotary. They require a K-member engine cradle open at the back to make this possible. The engine has to move down not only because it's taller, but because the T56 case and bellhousing are significantly larger in girth than the OEM 5-speed.





The steering rack has to move down to clear the balancer and oil pan which, as you might have guessed, is usually about half full of crankshaft counter weights and the rotating assembly at any given time. There's plenty of weight below the centerline of the crankshaft, in other words.

Depends on the engine, but you're right; the crankshaft (the single heaviest component in the engine, besides the block) is at the bottom of the block, and it sits lower in the car than the rotary's eccentric shaft. You can tell just by looking at the drive pulley location of both engines. The camshaft ends up at about the same height as the eccentric shaft.





The crankshaft doesn't sit any higher in the block. The block just has a skirt around the base which helps make the main caps and bottom end more rigid.

Well, except for the main caps, the thickest portion of the block, half of the crankshaft and about half of the rotating assembly, the oil pump, oil pan, and starter, etc.

The center of gravity of the average V8 is about midway between the crankshaft and the camshaft centerlines.

Sorry, just slightly tired of the stupid arguments. If you just said "LS1 swaps aren't for me", I would accept it, but talking like you an authority on the subject is why I am posting.

[Daishi00]

I stand corrected. See, you can learn something new every day

[edkwon]

Boring lookingg... like a Bonneville salt flat racer

[2000wrx]

See research FTW!!

[Brody8877]

Originally Posted by WhiteKnightSTi

You should learn to use proper capitalization and punctuation before you start calling people retards.

you're just mad that you cant afford one.

anyways, yall just jealous

[Brody8877]

Originally Posted by Skunkers

The other thing is this is RE Amemiya we're talking about here. The God of rotary tuners. I'm as big an LSx swap advocate as anyone, but no LS-swap RX-7 will ever have a chance of being remotely as well tuned as an RE Amemiya shop car. Ever. Yeah, the body may look a bit ugly and excessive, but I guarentee every single person calling "FAIL" on that has never, and probably will never, own a car that's as fast around a track as that car.

finally someone is on the same page as me.

[Daishi00]

Originally Posted by 2000wrx

See research FTW!!

Hey now, I did research, but it was years ago when this sort of conversion was being contemplated...I just lost interest before people actually got around to really doing it

but in my defense, Jimlab's LSx is an LS7 so he's running a dry sump which lets him drop the engine down even lower (gotta save some face here ).

[dclin]

Originally Posted by BurtonCR

Actually heres a better quote:




Sorry, just slightly tired of the stupid arguments. If you just said "LS1 swaps aren't for me", I would accept it, but talking like you an authority on the subject is why I am posting.

Sorry, just slightly tired of the stupid (LSx conversions are the sh@t!) arguments. If you just said "LS1 swaps ARE for me", I would accept it, but talking like you an authority on the subject is why I am posting.....

Yeah, I've been around the RX7 community for a little bit. I've followed Jim Labreck's exploits since near the end of the (RX7) Big List days, the late nineties, and I continued to follow his LSx build up on the RX7Club forums in what has to be the longest thread in the history of bulletin boards. He is truly a sharp, intelligent individual, probably one of the sharpest car guys out there, period. Ever.

But for all his eloquence and reasoning, the pictures you post clearly shows the rotary to sit further and lower. The rotary sits BEHIND the steering rack. The LSx (at least the ones not requiring cutting into the firewall) sits OVER IT. It's not clear since the steering rack is missing in the pic with his LSx mockup. The conversion requires bump steer correction. You have to relocate the steering rack. The angle of the pics is misleading as well. Get down to intake level and I'll bet you the difference is much more noticeable. There is still more LSx sitting higher than the rotary.

Fine, so LSx conversions don't instantly make the car handle like a UPS truck. Let me ask you this; do you know what the CG of a stock FD is compared to your typical LSx conversion? Difference in polar moment of inertia? As intelligent and as much thought he's put into his own conversion, I'm willing to bet that Labreck still wouldn't be able to say for sure.

I'm by no means a rotary zealot. When people decry the conversions as 'removing the RX7's soul', I want to puke. I can count more things I don't like about the rotary than I do. I'm not bashing the LSx conversion at all. In fact, I was damn near close to pulling to trigger on doing it myself. I do see the benefits of the conversion, and have no doubt that a LSx conversion can be made to handle very well. It's built on one of the best chassis ever, after all.

I did the research, and I liked the idea of having barrels of torque, and I liked the idea of a NA engine. Having said that, I decided in the end that the compromises I would have to make to keep the FD the way I wanted was not worth it. I want my A/C, I want my power steering, and I want it to pass emissions (ok, so I can't anyways ).

That, and I don't have the $40,000+ that Labreck put into his LS1 (just the engine mind you) to lighten it, etc. (though last time I checked, he tossed it in favor of a LS7 as mentioned above)

[Garwin]

Originally Posted by Brody8877

you're just mad that you cant afford one.

anyways, yall just jealous

You're really from SCIC, aren't you?

[amirul]

would look hotter if the rear is not covered!!

[dclin]

Originally Posted by dclin

[i]....

That, and I don't have the $40,000+ that Labreck put into his LS1 (just the engine mind you) to lighten it, etc. (though last time I checked, he tossed it in favor of a LS7 as mentioned above)

Correction: his original engine was a LT1. It's been a few years.

[BurtonCR]

Originally Posted by dclin

I did the research, and I liked the idea of having barrels of torque, and I liked the idea of a NA engine. Having said that, I decided in the end that the compromises I would have to make to keep the FD the way I wanted was not worth it. I want my A/C, I want my power steering, and I want it to pass emissions (ok, so I can't anyways ).

That, and I don't have the $40,000+ that Labreck put into his LS1 (just the engine mind you) to lighten it, etc. (though last time I checked, he tossed it in favor of a LS7 as mentioned above)

Next time you are in Dallas, PM me, I will take you for a drive in my LS2 FD. It has AC, PS, and even passes emissions with flying colors , oh and it's dead reliable with 380whp. I definitely did not spend 40k on it.

[dclin]

Originally Posted by BurtonCR

Next time you are in Dallas, PM me, I will take you for a drive in my LS2 FD. It has AC, PS, and even passes emissions with flying colors , oh and it's dead reliable with 380whp. I definitely did not spend 40k on it.

I'll take you up on that. When I finish my bottom-up resto of the FD this spring (crosses fingers), I'll bring it up for visit. I was already planning on visiting some Dallas friends.

[Skunkers]

+1 for Jimlab

I spent a good two years doing nothing but lurking rx7 forums several years back when I wanted to get an FD. He is indeed one of the smartest car enthusiasts I've ever seen. Actually, there are a lot of really, really intelligent people over at rx7club. Jimlab's posts and information over the years are actually probably the driving reason behind why I actually love the LSx motors today.

FWIW, on the LS-swap FD idea: I think that history has shown that the LS-swap does in actual fact slightly mess up that handling of swapped FD's. Not by much, but I've never seen one able to actually outhandle a 13B equipped one. That could be due to a variety of issues, from people just not placing the engine right, the polar moment of inertia, CoG, or just that the setup wasn't designed by engineers at a factory, whatever. Interestingly, the balance is typically actually better than having the 3-rotor 20B swap. When it comes to owning a street car, I'm absolutely 100% for swapping a LSx in. What small sacrifice you make in handling you easily make up for with a boatload of torque, and an engine you can actually count on everyday. When it comes to actually having a highly tuned track FD or weekend only car, there's a lot to be said for just keeping the 13B.

Once again, comparing a LSx homebuilt frankenstein to an RE Amemiya shop car is straight lunacy, though.

[h2o]

Originally Posted by jigga

front looks nice... back end looks... umm... I wonder how it would looks without the panel covering the wheel ??

[Chiketkd]

It looks 10x better w/o those wheel panels!