phoenix7

true to an extent. Those are the concerns I had and was thinking about. I wasn't necessarilly SAYING the V8 swap was faulty. I was merely mentioning what I THOUGHT could be an issue and YOU guys would know better and possibly correct me. I am a diehard rotary fan (if I wanted a piston engined car I would have bought something else) and I'm just interested in what you guys have done. My interest, however, is not strong enough to enroll in another forum just to read. i thought maybe you guys would know how to clear up any misconceptions but I guess I have to go to another forum where ppl know how to explain things to noobs better.

It was kinda fun. ttyl.

DCrosby

Listen, I come off as a Dick sometime, and if you think I am, that's fine, but you have to realize, we get a lot of flack for what we did, and we're not trying to tell you that LS1's are THE Solution, they are A Solution, of which there are many. We get stragglers in here asking questions over and over about weight, and bumpsteer, and all sorts of issues, most of which can be answered with a couple of searches.

I applaud you for trying to get the "Real" story, and the truth is anything worth while doing isn't easy, weather rebuild your own rotary or putting in an LS1. I just wanted to let you know that I gave the rotary a chance, and not half hearted, like let's see when this POS will blow... but I loved having something "Unique" and I Paid for that uniquenes... to the tune of almost 60K, (Not Incl. the original FD) I could have bought a Z06 outright for that cash, but the stuff I learned, the people I met, and the experiences I've had would have been different... and I don't think they would have been better...
So I don't regret what I've done, but it hasn't been easy, and it han't always been fun, but I came out the other side... and that side happened to be an LS1... for you it might be a 3 Rotor... who knows...

It's good that you're curious, just understand that we've gotten a lot of flack and are a bit protective / defensive of our descision....

gnx7

iTrader: (10)

Phoenix7-
Have you ever taken your car to an AutoX or road course? or are you a keyboard warrior?

jimlab

So you'd buy a Pontiac Aztek if it were powered by a rotary?

If a car looks like ****, I'm not buying one no matter what's under the hood, so to say you based your purchase solely on the engine is absolute horseshit. If you like the way your car looks and handles, then why is it so difficult to understand why someone would want the same car, but not the potential headaches associated with what is, after all, not a perfect engine?

People who ignore the attraction of the styling, handling, and light weight of RX-7s and claim that they own theirs solely because they love rotary engines make me laugh. "If I wanted a V8, I'd buy something else." Right, because that's the only logical alternative.

slo

iTrader: (1)

Plenty of people drive rx7's because they like only the rotary engine aspect. they Just mostly drive FC's and FB's not FD's,

I have nothing against a V8 swap, though I wouldn't do one myself, I would consider buying an allready swapped car if the price was right.

I like FD's, I just think that a well modded C5 or C6 corvette can easily be a better car (ok not better looking).

And now that a good condition C5 can be had for under 20K......

Orr89rocz

vette would probly be a better buy if you can get them at a good price at or below 20K. unless your handy with your work and can find a blown RX7 FD roller and a lS1 swap for good price and can do it mostly yourself

I applaud your guys work... an LSX FD is one of my dream cars. i dont care how you argue against it, there is not better motor than the LSx's bang for buck in power/weight/economy. just amazing motors

wptrx7

I think that's the point though, Why not have the best of both worlds: The looks, reliabilty and the power of a LSx/FD.

Luigi

jimlab

FACT: The main reason people replace engines are because they already own a car with a blown engine.

In most cases, they're not in a position to consider whether they should "just go buy a car that already has a V8" instead. They're considering how best to fix the car they already have. However, the fact that people are now actively looking for engine-less RX-7s to convert speaks for how popular and successful the combination is.

But when it comes right down to it, that's not really what pisses most "rotary lovers" off. The problem isn't really that people are replacing rotary engines with V8s, because how can you argue logically about something that increases performance and reliability and doesn't ruin the handling characteristics of the car, especially when it's someone else's car?

No, I suspect it's the possibility that the unarguable advantages and success of V8 conversions makes those with an emotional and illogical attachment to rotary engines look like ******* idiots that really bothers them.

phoenix7

that's the thing Jimlab. BECAUSE it's someone else's car THEY (YOU) should be able to say:

"no, even though the motor sit much higher that the stock motor it does not affect handling because..."

Or

"no, you retard. Just because 1/2 the motor and accessories are PAST the front axle doesn't mean handling is affected because..."

OR

"Look chump, Having 400HP available at 2500RPM does not affect the way a 2800lbs car handles because..."

So you can call it an emotional, illogical fascination with the rotary but I call it like I see it and no one has shown me anything yet. All I know is that it makes power and you don't need to do as much maintenance (which is where your reliability argument comes in.).

jimlab

And yet you've done nothing more than make a lot of baseless assumptions, all of which have been proven inaccurate, some many times over.

Was there another reason why we should be impressed with and give consideration to your opinions, or is "I call it like I see it" all you've got?

digitalsolo

iTrader: (2)

Your argument is utterly nonsensical. You're right, the accessories are past the front axle (though behind the wheels), and the engine is higher. The flaw in your line of thinking begins where you believe that these differences are somehow beyond the most basic of tuning to resolve. You're right, an LS1-FD (or FC) is starting with a (for comparison's sake) 95% race ready car, vs. a 98% race ready car; damn, a slightly stiffer set of springs might be necessary to equal a rotary powered FD in skidpad or slalom.

I'm not even going to touch on the "there is too much torque" argument. That just means you need better shoes driving the car. Rotary, V6, V8, V12, boxer, whatever, ANY car is going to be geared to have maximum torque available where they need it in the power range, if they're serious. To try to act like the torque occuring at 2500 RPM is a problem, is just ignorant.

Now, do you have any real points, or are you going to keep pulling these out of your ***?

phoenix7

typical Jimlab, They're not my opinions on the swap, I have not said you guys are retards for doing this. I'm COMMUNICATING TO YOU WHAT I SEE and what I THINK are issues and no one has given me concrete answers to disprove anything. All I've heard was I corner weighed it and it is perfect and you're a retard for not knowing what we did without us giving you details.

Digital: You say they are baseless assumptions that can be fixed with tuning, but I don't know what tuning you guys did. I don't know how you balanced things out. I don't know how the suspension was set up (besides "i corner weighed it"). all I know is that one of you guys cornerweighed your LS-FD without ABS or P.S. and got a 19lbs. increase over stock. How did he do it? What problems did he see/experience? How did he fix it?

then some other guy posts that he say a 100lbs. difference in a fully dressed LSFD. How?

Yes, I agree my questions might not make the most sense but that's because I don't know how you guys set up your cars or why.

To basically sum up what I know:

the LS powerplant is physically bigger and heavier.

You need to run a t-56 tranny and either a Ford rear end or some other form of rear end and special bracing.

the weight differences between stock FD and LS FD ranges from 20lbs to 150lbs or more.

I don't know how your cars were set up nor do I what you changed n order to make it work. I could go searching for days so apease my curiosity but I thought some of you might have been able to say: "I noticed THIS was bad/wrong/uneven after the swap and I fixed it by doing this:"

I've never had the pleasure of seeing a FINISHED LSFD so I couldn't see any flaws or problems besides what's in the pictures I've seen. You may think I'm retarded but when I see a 13b-REW and then I see the LS motor in an FD I can visually see how much bigger/taller it is. Please excuse my assumptions but that's all I've got and none of you have given me any real answers to help me move from the IGNORANT CATEGORY to the "Oh, I see" category.



This is the most useless group of tuners I've ever seen. Why don't you guys just say: "**** you, we don't want to give you any information!" Granted I can go to GrannySpeed or any other personal webpage and see their kits on how to do the swap but they'll never tell me of any issues with the frame flexing, or how the handling characteristics CHANGE when installing with motor etc. etc.

I've totally lost interest now (not that anyone cares) because no one is willing to step up and explain the pro's and cons ( the REAL issues) this swap MAY have. I will not hesitate to say I am ignorant on this issue but you guys ARE RETARDS for not being able to coheretly give YOUR honest opinion (not because of the swap.)

When you guys are done with the super defensive answers let me know. I'm not here to talk ****, I'm not here to call you retards for swapping in the LS or useless rotary mechanics, or anything like that. I just wanted to get my preconceived notions straightened out but it looks like that isn't happening anymore.

I honestly don't think I was posting anything negative or derrogatory against any of you or your cars ( although I rub people the wrong way most of the time, which, to be honest, doesn't bother me). Some of you tried to start talking and the rest went on the defensive (like calling a homo that hasn't come outof the closet a "***" and he gets all defensive and upset). I guess I should take your defensiveness and your inability to explain things to me as my sole answer regarding this unorthodox (now becoming the norm apparently). Remember not everyone is attacking you or your decision to swap in a boinger.


My final say: It has been confirmed. The world goes round and round not up and down. Those who claimed it was flat couldn't do it as coherently as those who said it was round.

digitalsolo

iTrader: (2)

No one is breaking down how the balance is brought back, because there is nothing to break down, it's not even tuning 101.

The weight bias of a headers/no AC/no PS LS1 doesn't significantly alter the handling so there is no voodoo in getting the balance back. It's no different then tuning suspension on a rotary car. Weigh the car, corner balance the car, and adjust your suspension/weighting as necessary to get it in balance. Rotary or piston has no real relevance. Yes, the polar moment is slightly worse with an LSx, but this magic number doesn't have any real relevance in any of the 9/10ths cars that people on here are building, and once again, the same suspension tuning and laws of physics that effect the rotary engined RX7 still apply to the V8 cars.

I don't understand your questions or argument. What are you trying to figure out? We've seen 1.13 g skidpads, we've seen corner weights from multiple cars, we've got guys winning autoX and open track days. There isn't any voodoo that anyone is doing or any secrets we're keeping. Put engine in, tune engine, tune suspension, go fast. It's simple, I promise.

DCrosby

And there are plenty of threads outlining the advantages and disadvantages of Granny's Vs. Hinson's etc... On Height, and Bump Steer Correction, all those "Issues" have pro's and cons, but none that make the car "un-driveable". I wouldn't mind addressing specifics you would like to know about, but this tell me what you don't like business is kind of strange... that's like asking a 3 Rotor Guy how he feels about the understeer !? He deals with it, or he sells the car... is how he feels about it...

I personally am running the stock Torsen, for a couple of reasons,
1) it hasn't broken
2) I like the feel of it
3) I didn't want to shell out thousands to fix something that hasn't broken yet
4) I don't go drag racing
5) I figure wheel hop = greatest killer of diff. so I got better bushings, so I have little to no wheel hop

As to Power Steering and AC:
My car already feels uncomfortable on the streets of L.A. it's a rough ride... so I can choose to call it quits, register it off-road, and take the interior out and make it a racecar, OR I can keep some creature comfort, and have a nice stereo, PS., AC. etc... and have a "Slightly" bloated FD. Figuring I had an R1 (Second Lightest) I could afford to put on a couple of pounds...

Is that the kind of "Investigation" you were looking for ?

-DC

jimlab

Key word: THINK...

I THINK something is wrong, therefore YOU have to prove to me that it isn't. Does that pretty much sum up your position?

Do your OWN research, then provide us with FACTS that support what you THINK. Start with the center of gravity of a pushrod V8 engine with aluminum heads and a composite intake...

Well, you got something right...

Pal, we don't OWE you an explanation.

jimlab

OK, what the hell. I'll address some of your "concerns".

The LSx is marginally bigger, and marginally heavier than the rotary it replaces, at least in the FD. What you're not considering is the weight of the cast iron exhaust and turbo manifolds, turbos, intercooler, piping, and all of the other crap that allows a 13B-REW to make more power than a 13B. It all weighs something.

Jeff Hoskinson took a fully dressed 13B-REW to a junk yard in the back of his pickup and weighed it, then subtracted the empty weight of the truck. Those scales are recalibrated frequently, are very accurate, and typically have a maximum margin of error of +/- 20 lbs. The weight he got was 430 lbs. It could have been a little heavier, or it might have been a little lighter, but at the time, almost everyone was surprised by the weight. After all, it's such a compact motor... when you're only thinking about the housing/plate core.

An LS1 with full accessories weighs an estimated 460 lbs. with cast iron exhaust manifolds, which no one uses. An LT1 weighs ~520 lbs. equipped the same. When the first LT1 FD (a base model, I believe) was finished, it weighed in at ~2,950 lbs. with full accessories and emissions equipment, including catalytic converters, and 50 lbs. of ballast in the hatch that Grant (Granny's) recommended to balance weight front to rear, as if A) that was a good idea, and B) 51/49 wasn't good enough.

Corner balancing is more important to neutral handling, BTW. 50/50 weight distribution front to rear is great on paper, but the minute you put a passenger in the car, that changes, and the minute the car starts to corner, accelerate, and brake (you know, all the things you do while driving...) 50/50 goes out the window. Corner balance the car, ideally while using ballast to simulate the driver's weight, and it'll handle the same way in a left turn as it will in a right turn. That's all that really matters.

I think you're judging weight by perceived size, and not only isn't that an accurate means of estimating, but it's as bad as assuming that an LS7 is heavier than an LS1 because it has more displacement (427 CID vs. 346 CID). Yes, we just had a thread where someone asked that very question.

As far as impact on the center of gravity, the weight of an LS1 is centered low in the block, where the single heaviest component in the engine (the crankshaft) is and the block casting is the thickest. FWIW, the crankshaft of a V8 sits lower in the car than the eccentric shaft of a rotary engine. Draw your own conclusions.

It is generally expected that you'll run a T56 6-speed because that's the manual transmission that the LSx was originally equipped with, and because the frictional losses will be lower than an automatic, but that doesn't mean you have to use a T56. It also happens to be a ****-ton stronger than the OEM 5-speeds and has a deeper 2nd overdrive gear for better fuel economy, so there's no point in wasting time and money adapting another transmission to the engine. Most junkyard LSx engines are going to come with a transmission anyway, so why is this even an issue?

Inaccurate and incorrect. You don't have to change anything in the back of the car unless you're drag racing, and then it's only recommended that you upgrade to a TII or Kaaz differential (FD). No additional bracing is required.

The Ford 8.8" IRS conversions are the result of a lack of gear ratios for the stock differential. It's a fringe benefit that it just happens to be stronger, have more differential options, and add very little weight. 3.90:1 is the lowest RX-7 gear ratio that I know of, and while some people like the way their nearly stock LS1 cars drive with 3.90 and 4.10 differentials, the more low end torque you have, the less gear you need in the back of the car to maintain streetability. The stock ring and pinion in the 6-speed Camaro/Firebird and Corvette is 3.42:1, and the Viper has a 3.07 R&P ratio, FWIW.

The weight difference between the various models alone can account for most of that.

The 5M base model weighs in at 2,789 lbs. and the 4A Touring/PEP weighs in at 2,923 lbs, a difference of 134 lbs. Gas weighs ~6.2 lbs. per gallon, and with a 20 gallon tank, an FD can vary in weight by 100 lbs. or more just by how full the tank is. You've got a 200+ lb. range there without even removing a bolt.

You cannot make assumptions on the amount of weight added by the conversion simply by looking at scale weights for completed cars. Unless the owner has before and after weights, with the same amount of fuel in the tank (or compensating for any additional or missing fuel), from the same scale, there's no real way of knowing precisely how much weight the conversion itself adds (or doesn't). Roll bars, stereo upgrades, tire/wheel changes, and other modifications all impact the curb weight of the car. You're extremely unlikely to find someone who has done a conversion without changing anything else at the same time, or who took the time to get a weight measurement for their car before the conversion.

Then here's a question for you... Why do you assume that something had to be changed to "make it work" before you've READ that something had to be changed to make it work?

You keep saying you don't know these things and just want to find out, but your posts don't indicate that at all. That's the reason you're getting the reception you are.

Believe it or not, that's not our job. All the information above is readily available and has been discussed before.

65Imp

iTrader: (8)

I gotta say props to Jim for replying with all the info, as he has for several years rather than saying f-it, and letting you be upset. I know you may see it as an attack, but many of us research a ton before posting. It just seems that your opinion is vocalized before much research. If you are not willing to think outside the box, then any engine swap is not for you. Here's some reaing material that may be interesting for you

here's a place for more info on the generic swap:
http://www.hinsonsupercars.com/faqFD.htm
they have likely done more swaps than anyone else, for several years now. The site has a ton of info.

here is a place for more in depth info:
http://www.v8rx7forum.com
http://www.swapcartech.com/forum/index.php
but beware, many of these guys have done the swap and are huge fans of the final result. You will likely find any answers you have there with a quick search.
If you want to see a great example of a daily driver FD check out danzan149's car. He drives that thing up to mammoth from So Cal in the snow with chains on to go skiing several times a year!
Or if you want to see a more track oriented beast take a look at NaTerry's car, and videos. I have never seen track videos that have that kind of domination, and his engine is nowhere near max effort.


Since you seem quite concerned about weight let me guide you to my post here:

http://www.swapcartech.com/forum/sho...ghlight=weight

I cannot take credit for all the info, but it seems comprehensive weight info on the FD is hard to come by since mantissa went down, so i posted everything I could find there. Much of it also entails making the ls1 more lightweight. Similar weight reduction can be had by modifying the 13b-rew. As Jim stated 150 lbs varies between rotary powered FD's. So you will likely see a large weight difference with ls1 swapped cars, as they are all custom. Each owner makes his car to suit him, so the weight can vary a great deal depending on if weight is a concern to the owner. Also understand with the power curve of the ls1 and the gearing in the stock fd diff, more weight is of very little concern to the majority of these swap owners. 4.11 gearing in a v8 is considered pretty intense, especially when the car is over 500 lbs lighter than anything that the engine was ever installed in.

I hope some of this info helps you understand why some of us swap ls1 engines into our FD's. Many long term members of the FD community have chosen to take this road. Others have stayed rotary powered, but most of them no longer slam the swap, as the potency and potential have been demonstrated. To each their own.

Orr89rocz

very good posts there by you two. that should definately clear up any confusion...

jimlab

Until the next time someone refuses to do their own searching...

t-von

iTrader: (8)

He's not assuming. He's stating fact. The facts are that the rotary sits lower and further back with-in the engine bay creating a lower center of gravity. 50/50 is only half the story. You want as much weight as close to the center of the vehicle as possible. This is how you improve the vehicle reflexes & turnin. Truthfully the differences between the v8 and rotary aren't going to be that noticable to the average Joe, but a very experienced driver will notice a differance.

jimlab

Now you're assuming. Where is the center of gravity of a rotary engine?

The eccentric shaft of a rotary is higher in the car than the crankshaft of an LS1, and at any given time, half of the rotating mass of the V8 is below the centerline of the crankshaft. At any given time, only perhaps 1/3 of the rotating mass of the rotary is below the centerline of the eccentric shaft.

phoenix7

can I drive one of your LS7's? I think GNX7 is the closest one but I don't think he's built any LS FD/FCs recently.

DCrosby

Exactly, and I'm not arrogant enough to tell anyone that I'm in tune enough to tell how "Balanced" the car was before the swap, and certainly a year later, after the swap, I was just happy to see my car again.....

If you're doing the swap to a track car, you might have a point on handling, and the weight, but fact that now you're running in classes like the Radical, and Flat out racecars might leave you to build something lighter / faster for your $$ anyhow.....

For most of "Us" V8 Guys, it's a great solution to an ongoing / aging problem....

wptrx7

He's building one now, What are you talking about?

jimlab

Is he?