After driving a 911 and RX7 back to back today, all day. i dunno which one to build!!

[mas28O]

Scottie-GNZ, you are right. Hypertek take that talk back to RX7club. The fact is that I only gained 28lb from the swap and the balance of the car is now better than it was with the rotary motor. I have allways liked reliable power over problem motors that do not make any TQ...

[JMortensen]

OK I'm not against hybrids AT ALL, but I don't understand how you guys could be right with your statements.

 

Even as a lifetime (seems like it ) 911 owner, I have to admit the FD is an amazing car made even more amazing with LS1 or GN power. My buddies GN-powered fully loaded 93 with a/c, Bose, etc weighs in a 2,790 w/o driver. The LS1 swap should weigh in about the same and be a well-balanced and better driver than the 911 conversion. Only drawback to the FD is the 4.11 final drive. Same problem in the 911 unless you use turbo transaxle. A TT LS1 FD is on my wish list

 

Scottie, the LS1 is significantly LIGHTER than a Porsche flat 6. Just did some quick checking on the net, looks like the 3.6 Turbo weighs in at 268 kg, which is 589 lbs if my math is right. Source: http://www.sikhworld.co.uk/Porsche%20911/Porsche911page8.html By comparison the LS1 = 456 lbs fully dressed (auto) or 497 fully dressed (stick) according to this website: http://www.corvetteactioncenter.com/specs/z06/ls1ls6.html So the weight distribution of the Porsche would significantly change, but it would become more even front to rear.

 

Scottie-GNZ, you are right. Hypertek take that talk back to RX7club. The fact is that I only gained 28lb from the swap and the balance of the car is now better than it was with the rotary motor. I have allways liked reliable power over problem motors that do not make any TQ...

The rotary is one of the lightest engines around. I don't see how you could swap in any V8 and only gain 25 lbs, unless the stock IC was made of lead. According to this site the 13B with all dressed but no turbo weighs 278 lbs. So how could the LS1, even a lighter automatic that only weighs 456 lbs, only end up 25 lbs heavier? I don't think the turbo and IC weighs 178 lbs. Plus, in addition to factoring in the extra weight, the V8 is going to have a higher cg than the rotary and it is going to be significantly farther forward in the chassis than the rotary, which would be detrimental to handling. I'm not saying it won't handle. What I'm saying is that it will lose the weight advantage that the smaller more compact rotary had.

 

This was brought up on this thread here: http://forums.hybridz.org/showthread.php?t=104198 and never resolved really.

 

I'm all for LS1 RX7's and Porsches, but I don't understand how your guys' numbers could possibly be accurate.

[mas28O]

Mike from JTR came over and used his car scales on my RX7 before the swap and after the swap and it only gained 28lbs. We also used a engine scale on both motors. You can not just compare engine weight to engine weight, this is why you weigh the car before and after the swap.

 

Rotary(93 tt) with 5 speed 565lbs

LS1 with 6 speed 590lbs

 

On my new FD it was a auto pig before

The motor and auto 635lbs

[LS1240Z]

Trust me.Mas280 is right about the weight being only 28lbs more.He pulled the motor from the RX7 and checked it on the scale and then checked the LS2...I was there and so was Mike (JTR).Rotary motors SUCK!...No power,no TQ,cost to much to build and still no power.

[JMortensen]

Guess I don't have much choice but to accept what you're saying since you've been there and I haven't, but it still doesn't sound right. Doesn't sound right at all.

[JMortensen]

One more time I'm not saying the rotary is the way to go, just questioning the weight distribution and gain that I keep hearing quoted.

[JMortensen]

Did some searching online, apparently it is the turbo and IC and plumbing that makes the difference and brings the weight pretty close to the LS1. So that's another plus for the LS1, makes the weight difference pretty inconsequential, although the cg would be moved slightly higher and the PMOI raised a bit it should still whoop *** on a 13B powered 7. So I guess I stand corrected. I still can't believe how much the turbo crap apparently weighs...

[Guest BoostedZ350]

Look I'm telling you go with the FD/LS-1 you will be stomping vettes, vipers, and pretty much anything street legal with just cam/header/nos. Hinson Supercars has FD/LS-1's running 8.70's in the 1/4 mile.......STREET LEGAL.

[Scottie-GNZ]

I am not sure where those weights are coming from. I helped strip the FD that has the GN power and it all added up. Every LS1 FD and the GN powered FD all came in within a few pounds over stock and none of those were strippers.

 

As for the 911 comment, my bad for not making my point clear. I was not referring to the difference in weight but the fact that a 911 has a heavy rear weight bias and the snappy torque of a big V-8 accentuated it. I drove one of the early Renegade kits and compared to my 911 I did not like the way it drove. Of course, it was not an LS1 but I am not sure if even 50-75lbs would have made that big a difference.

 

As for my sentiment towards the poster, I guess you would need to hang around the RX7club forum for a while to understand.

[MikeJTR]

At the risk of offending MAS280 and LS1240Z, I will have to say the LS1 V8 swap adds more than 28 lbs to the 1993 Mazda RX7.

For example, some techniques MAS280 used to reduce the weight gain of the V8 swaps included using a lighter-than-stock battery, small (lightweight) crank pulley, and a lightened flywheel.

Also, some parts were not installed after the V8 swap, such as the belly pan, which does weigh a few lbs.

Without giving away any secrets, MAS280 is building an LS2 stroker into a 1993 RX7, and one of the ways he is reducing weight is a single 3-1/2" exhaust instead of dual 2-1/2" exhaust.

Part of the exhaust can be seen on this link:

http://www.torquecentral.com/showthread.php?t=31345

[LS1240Z]

DAM YOU MIKE!...You offended me!

OK...so add 7 or 10 lbs,big deal.

Just go to the gym for a couple weeks and loose that weight.

[MikeJTR]

LS1240Z,

I think the battery alone saved about 15 lbs.

I believe your car was lightened by over 30 lbs, maybe even 50 lbs.

For example, I heard from a reliable source that the stroker crank going into your car was lightened (maybe another 15 lbs).

Oops, did I say "lightened stroker crank?"

Add in the lightened flywheel (maybe another 10 lbs), lightened crank pulley (perhaps another 5 lbs), and other weight saving tricks you did not disclose, and the weight gain of 28 lbs that you claim could be off over 50 lbs. Don't forget to include that your car does not have catalytic converters.

If you are going to drag my name into the "28 lb" weight gain of the LS1/RX7 swap, I am going to explain to others that the numbers cannot be trusted.

[LS1240Z]

Man....you must have been pretty board to get those exact numbers.Lighened flywheel....Who has that?Lets just put it this way.It's not enough weight to even be complaining about.The bottom line is.........It's one of the best convertions to do.Power to weight ratio....it cant be beat.

Drag your name into it?????Your starting to sound like 240Z2NV..LOL!

[Guest ON3GO]

guys please dont say the rotary is crap.. it isnt.

you just dont understand them maybe.

they DO make power, and they CAN make TONS of power.

they make torque too it just delivered in a different matter then the LS1.

im a BIG rotary fan, and if you drive a well built rotary RX7 you will understand where im coming from.. its like nothing else you have ever driven.

 

but im gonna do the RX7 V8.. maybe not LS1 though.

 

mike

[Owen]

Word up, I agree to that. I got to ride in a 9sec FD drag car in Japan and I went in saying, this is gonna be so-so...(didn't know the capability of the car at the time) that f-ing car FLEW! And it was pretty comfortable since it was made as a demo car for passengers to experience, meaning it wasn't stripped down to the bones.

 

I would do the LS1/LS2 on the FD and get a 20B for the FC. Those damn 20Bs cost so much though, that was my original plan...

Owen

[MikeJTR]

"The bottom line is.........It's one of the best convertions to do.Power to weight ratio....it cant be beat." LS1240Z talking about a 1993 Mazda RX7 LS1 V8 swap.

 

Actually, a 240Z with an LS1 has a better power to weight ratio than a 1993 RX7 with an LS1.

[LS1240Z]

Right again.Your so smart....LOL!

 

Actually, a 240Z with an LS1 has a better power to weight ratio than a 1993 RX7 with an LS1.

[Cable]

.......and one of the ways he is reducing weight is a single 3-1/2" exhaust instead of dual 2-1/2" exhaust.

Part of the exhaust can be seen on this link:

http://www.torquecentral.com/showthread.php?t=31345

 

Where did he get his 3.5" stainless muffler?

[Here comes trouble]

Obvious solution.....build em both with a third as a novelty project with an American Motors vintage flat head 6 transplant

[roamer]

I have been considering a LS1 swap for some time now. I have considered z's, 951's (944 turbos) and RX-7's. I have also driven numerous 911's and 930's. For me, when considering swaps, the question came down to whether the swap improved the car. A 930 turbo has a race motor, stock. It is simply a better motor than an LS1 (which is an amazing motor in its own right, it just is not as 'track ready as a Porsche 3.3 turbo) and can easily be made to make equal or more power. So with a 930, stick with stock since making the swap is not cost effective (even with the Porsche tax) and you won't necessarily end up with a better car.

 

However, with 951's and RX-7's, the stock motors are ticking time bombs and will cost serious & to make significant power upgrades. Where you can do a swap, maintain or improve handling, increase hp and increase reliability, why not? An LS1 in either of these car simply fits the bill.

 

Z's only make sense because it costs mucho $ to get big hp out of the stock motors. Stock z motors are fantastic for what they are, so with z's I think it boils down to what your ultimate goal is. An LS1 won't necessarily make your car 'better', just faster.