LS1 FD corner weights versus stock FD
 

I weighed both cars over the weekend at our autocross event at giants stadium. Both cars had spare removed. Both had almost full tanks of gas but my car has a reduced capacity tank which holds 5 gallons less (5 gallons at 8 lbs/gallon = 40 lbs). Both had stock 16 x 8 rims but i had 245-45-16's Yok AO32R's and rotary had 265-45-16 Kumho ecsta v700's. My car is missing AC, PS and ABS. My battery is in bin on passenger side whereas stock RX7 has battery in original position up front. Bottom line is mine weighed about 15 lbs more but had a better weight distribution of 50.5/49.5 front to rear and his stock RX7 was 53/47:
--------------LS1 ------- Rotary
Left Front: 684 ------- 718
Right Front: 695 ------- 718
Total Front: 1379 ------- 1436

Left Rear: 705 ------- 660
Right Rear: 645 ------- 618
Total Rear: 1350 ------- 1278
TOTAL: 2729 ------- 2714
% over Front: .505 ------- .530
% over Rear: .495 ------- .470

Yes, the rotaty places about 55 lbs more over the front tires!!! incredible!!

the owner of the stock RX7 was my passenger on the last run; listen to his comments at the very end:
http://207.127.219.37/video/AX.wmv

hmm now if you had ps, ac, and abs like he had, i wonder what you would weight then, and with the battery in the stock location.

well that 55 lb is easy in ac,ps,abs, and a battery. so when he has all that removed and moved re weigh them

Agreed. At a minimum that's 50lbs, probably a lot closer to 100lb, worth of stuff. The LS1 is a good choice as far as weight if you feel you have to do something like this. But this is an apples and oranges comparison to say the least.

Not to mention if the rotary had a lightweight aftermarket downpipe and take off the air pump, the weight difference would've been more than 100 lbs.

Just weighed my old ls1 p/s pump and ac compressor. 7 pounds and 15 pounds on a bathroom scale. Woneder how much the lines, abs unit, fluid, and ac condensor would add? My guess would be 25 lbs.

Well maybe if he did that, and then figured out a way to add 150whp without sacrificing low end grunt he wouldn't get dragged around the course like he did. lol

Is the ls1 car a touring model?

The RX-7 could remove this weight from the front...

-35 lbs battery to back
-20 lbs air pump
-38 lbs power steering & A/C
-10 lbs lightweight pulleys & flywheel
-15 lbs SS downpipe or -25+ lbs single turbo conversion
---------
-118+ lbs easy

What do you have left to take off from the front? Go troll somewhere else.

Funny...right underneath "Race Car Tech" it says "Discuss anything related to road racing and auto X." as what is to be posted in this section. Funny how it doesn't say post anything related to "rotary" road racing and autox. So I fail to see how posting his results along with another RX7 owner's impressions could be classified as "trolling."

I've stripped a 94 and shiped most of those parts so I know your way off on everything but the batery. ;)

I can remember when Jimlab first started his conversion and told folks of how close the weight would be...

Chalk another one up for ol Jimboy. :D

no sunroof in all of his pics

hi, i put the vid on another server for faster download:
http://scott.ohyesh.com/videos/ax.wmv

i know its not true apples to apples, but its as close as i could get :) i posted the event in northeast section but no one turned out besides this regular (non-rx7club) guy. its accurate info that is useful and not widely known. my car is a base model, no bose, no sunroof, but i don't know what trim its called in rx7 speak (base?). he's not going to change or remove those items you guys mentioned because he races in SCCA "SS" class (its a stock car class).

i'm sure you all read the other threads that turn ugly. this is pure technical stuff.
so i just have to figure out how to get ABS installed since the whole system was removed. i do see its value for autocross, although i didn't lock up on the road course days.

So the question that lingers: Which car was faster in the Autocross?

I'll update with official times when they are released, but my fastest time was 54.0 and his was 56.0. His tires (265-45-16 kumbo ecsta v700) were way better than mine (yok AO32R 245-45-16 Hard compound), no comparision. they were wider and stickier. My yok's are hard compound and are better on road courses than autocross. He is SCCA SS class driver that is original owner of the car, which is 93 R1. He races full season and competes in Kopeka, but this was my first autocross of the year!! and my first time ever autocrossing any RX7. He has stock R1 springs (stiffer than my stock non-R1 springs?) and $2000 koni custom valved double adjustable shocks (tripoint) and i have 13 year old stock units. The lack of ABS in my car definitely hurt my times as the video reflects constant right front tire lockup (dusty course, need new bleed because i just installed new master, need to adjust proportioning valve, who knows). He loved the car and how it felt on the course so that means a lot coming from a die hard rotary owner/racer.

People go so far out of there way to argue against the weight of the LS1 :rolleyes:

Is it not safe to say that regardless of airpumps, battery location, downpipes etc that an LS1 FD has no real weight disadvantage compared to an FD with any amount of engine mods? If you think not then I say you're just being argumentative and looking for any excuse to bash the LS1. Every guy I know with some real FD driving experience has been floored by the performance of the LS1 cars.

I could tell that was Sandro when I heard his voice on the video.
One important thing not mentioned: the E-mod index is a killer.
Point-->13b rew or any other Mazda engine in SM2.

finky, yes that is sandro. awesome guy! he wanted me to use his tires after i gave him a ride because mine were so much less effective. maybe improvement of 1 to 2 more seconds? who knows. lets not go there :) i would have but i left early for wedding.

The LS1 haters don't like it because it's not SM2 legal? No way.

GJ 2mchpwr :) I have auto-xed my LS1 FD once already and it was a blast. Just to back you up, here's my car corner weighted before and after the swap WITH ac, ps, abs:

1993 touring

Before swap

LF 729 RF 695
LR 705 RR 692

Total--2821lbs

After swap 1999 ls1/t56 trans ac, abs, power steering

LF 748 RF 717
LR 683 RR 700

Total weight 2848lbs

Weight gain only 27lbs

fwiw, i was going to come but couldn't make it. :(

Cant argue with the facts... the Ls1 OWNS~!

Hey finky, this is Malik with the ex-red LS1 TII :)

Yeah, e-mod index kills but it was just too much fun to drive my car at the Auburn Hills AutoX so I for one wasn't that concerned. I just wanted to have some fun, which is why I'm building the successor, I'm pretty sure I'll never develop my driving skills enough to compete in a class anyway :) And it's still fun to compare times with other people from other classes, and just as valid no matter what the index puts you at in the end. A faster car is a faster car, no matter what it has in it. And just to stir things up, finky's car was way faster around than mine (driving skill and tires probably had a lot to do with that) so people shouldn't just assume you're going to be faster at AutoX because you have an LS1 in it :D

Most of the weight data comes from here...

http://www.mantissaconsulting.com/et...eight_data.htm

It's not just the parts themselves but brackets, hoses, emmissions, etc that aren't needed when the main part is removed. I have used a scale to confirm the downpipe, pulleys+flywheel and battery myself. Everything else seems reasonable to me.

Some people like to compare apples to oranges. The fact is the rotary engine is lighter than an LS1 even if it's not a lot. It's pretty dumb to post how my stripped down LS1 RX-7 weighs less than a more stock RX-7. It's kind of like saying how weak those Corvettes are because my modded RX-7 embarassed a stock Vette. There in is the trolling. Talking about how the LS1 RX-7 did at the autocross and the corner weights is fine though.

matt hey, are you calling ME a troll? i thought my post was very informative. i left nothing out. i gave the facts and the weights so everyone can read what was in each car. no surprises. i keep reading how much more the ls1 weighs and it kills the handling of the car. my goal was just to show that when properly executed, that is not the case.

hey this is VERY close to an apples to apples comparison, its not like the LS1FD has no interior! you sir, are a piece of work! hahahahaaaa! hilarious! we are only talking about 20 pounds of items removed from the LS1FD! I know, I removed those same items from my FC and its far less than what people say, and yes I weighed my items on a certified scale at work calibrated to weigh items between 2 and 45 pounds.

typical rotary lover -
"an LS1 adds over 100 pounds and the car will handle like a nose heavy pig"

typical LS1rx7 guy after doing his own swap -
"holy crap, my car is faster, gets better mpg AND it handles just like it did before!"

its sad there are so many rx7 guys that cant understand the overall package an LS1RX7 presents its driver. its an amazing car, wickedly fast, without much work at all and incredibly nimble thanks to the wonderful job GM finally did on a V8 motor design.... all aluminum motor and a plastic intake? BRAVO!

Yes, your post has a lot of good information. Yes, the LS1 is a light and compact engine that can be put in an RX-7 without giving up anything over a stock RX-7. A rotary RX-7 stripped and modded to the same level will be lighter, handle better, break better, and be cheaper. The LS1 RX-7 will have more torque and better reliability. The LS1 will get better fuel mileage also with a 6 speed. My problem was with this statement...

"Yes, the rotaty places about 55 lbs more over the front tires!!! incredible!!"

You didn't say the other RX-7 and this statement looks like you are trying to make the rotary look bad like it has something to do with the rotary which it doesn't. Why out of all the cars at the track you choose to compare to the "rotary"? Maybe this wasn't your intension. If that is the case I apologize.

most with reading comprehension skills above 4th grade would know I'm talking specifically about the car in the video and the one I described in the first paragraph. I would like to edit it now since you pointed that out but we can't edit.

are you kidding? because we have same chassis but different motors and its good to see if the v8 in my application was a bad move with regards to handling. I found out the answer to my question first hand.

I beleive the only problem is see, is how some people just brag how the ls1 is amazing, and then they come down in the rotary is if it were crap. Sure the ls1 is a good strong motor, with cheap, relaible power. But with any motor once you start pushing some decent hp numbers, all this relibality talk goes right out the window. Im not bashing or praising the ls1. Personally, I prefer the feel of a rotary, but thats me. To each his own

besides more power means youll win a autox race?! its all driver anyways.

The Ls1 conversion is great if budget is the main priority. At least if there is no forced induction mixed in with the conversion. I am not going to bash anyone's car. I drove my friend's 2nd gen Ls1 recently and I must say, It was just as fast as his to4e. It's a little weird, sounded and drove like my sister's 03 trans-am. amazingly.....hehe

Thanks for the factual data we can now reference.

I would like to see, putting budget aside, someone drop an all aluminum 13B into a 3rd gen. Corner balance the differences of the two cars and track test them as well. Wouldn't that be comparing apples to apples? The difference of a cast aluminum rotor housing vs. a cast iron housing is staggering.

MAzda needs to price the next rx7 in the corvette market and give us an all aluminum rotary 4th gen.

here is what should be posted

Thanks for the information!!!

I've seen the syndrome where people have to have the biggest and the best or at least better than everyone else. They also like to justify all the money they spent to get what they thought was the biggest and the baddest. I'm not saying that's anyone in particular but LS1 owners seem to pop up now and again bragging how their done over car weighs so little. If weight was so important to them then they should have kept the rotary and stripped it down because it would weigh less than an LS1 RX-7. Some LS1 owners talk about how the LS1 makes so much power like the rotary doesn't. The rotary can make plenty of power and can hang with an LS-1 which is a much bigger and newer engine. The rotary still has it's advantages and strong points that some people like to dismiss.

They do that to prove to the whining rotards that the car does NOT turn into a front heavy pig with the LS1. Then the rotards will trumpet some schpeel about 2% better weight distribution. Give me a break.

When the LS1 car goes out there and turns much faster times and experienced FD drivers say it's faster what is there left to argue about? For some reason the rotary ego cannot handle the idea of a pushrod motor. It's stupid.

Really? Can you post a pic of said car?

Last I checked the Firebird and camaro stopped being produced in 2002.

Please go back to 2JZ land and stop spouting bullshit and lies.

A LS1 RX7 doesnt handle anything like a Camaro or Firebird. Sound yes but thats about it.....moron.

Thanks for the info.
I had long time been believing rotary was compact and light engine until I actually held 13B short block by my hands. I don't know how much aluminum plates cost more but I think Mazda should go that way sometime in the future.

"Really? Can you post a pic of said car?

Last I checked the Firebird and camaro stopped being produced in 2002.

Please go back to 2JZ land and stop spouting bullshit and lies.

A LS1 RX7 doesnt handle anything like a Camaro or Firebird. Sound yes but thats about it.....moron."


Why do you need a picture to believe this. I'm not off 20 years or something.
She had the last year model. WIth intake, exhaust, and a few other things. What was it 2002, 2001, I really don't keep track of trans-ams. She traded it in for a G35.

I am not saying the handleing of your loved LS1 rx7 is the same as a stock trans-am. The trans-am is a fat pig compared to a 3rd gen. However, the cars drove the same in a straight line. In terms of the vibration from the engine, transmission, and clutch. IT was the close to the same. Obviously, the 3rd gen kills it in power to weight ratio and anything suspension, steering related.

I am not trying to say which car is better. You can turn any car with the right amount of mods into a high performance machine. If I wanted a V8 with tons of power I would buy a corvette. If I wanted something different. I would buy a Z06 strip it out and mount a 20B turbo in. That is actually becoming my dream car......no,its not.

Do aluminum housings exist?

housings, rotary
 

YES , both rotor housings and end housings or side plates.

I agree the stock rotary housings are incredibly heavy, if they were always made of aluminum then I would concede that the rotary is a MUCH lighter motor.... but aluminum housings are very rare. So, an all-aluminum rotary would be lighter than the off-the-shelf (outta the junkyard?) LS1, but at what cost? one of the greatest benefits of ther LS1 is its light weight yet big power in its stock form, this reduces build cost and build time. also, dont forget there are ways to make an LS1 lose a few pounds, superlight pistons and rods, a knife edged crank, hollow camshaft and lightweight valvetrain plus an electric water pump could shave 50+ of pounds from the block just ;like your aluminum housings will help your dreamland super-rotary.

geeez, I would like to see an all out LS1FD vs. all out 20bFD vs. all out 13bFD battle... the suspension could be the same too! in fact why not try a supercharged LS1FD and a turbo'd LS1FD just for kicks. now who can get ESPN or SPEED to fund the buldups, I'm sure we'll just need a half million for the test, so you guys can see the "truth"... that no matter how you slice it, an LS1 is one of the very few motors worthy of replacing a rotary and it just happens to be a great fit inside the RX7 chassis.

I fail to beleive by just installing a ls1 the car automatically becomes a better handling car because of it. Not saying it wouldnt be faster for some drivers, but its all preference. Though I am also not as experienced as you guys, so thats just my opinion. I saw the ls1 Fd in the SCC ultimate car pulled a 1.095g, back in 91 for the g-force games, that FD pulled a 1.035 on G-force KDs. What tire was the ls1 running?

IMO Ls1 FDs make lots and lots of sense. The FD chassis is probably one of the best chassis ever made and this cures the one weak link to big reliable power.

BUT I like rotaries which is why I like RX7s and don't forget what 12k can do for a rotary hehe :)

Just give it time and you'll see Ls1s blowing up and having trouble as well. Usually power and trouble walk hand and hand.

Although I will admit that basic common sense leads me to beleive that a stock ls1 making 350 rwhp will outlast any rotary making equal power and because of the torque it will outperform it as well. The gas mileage might be a little better as well.

BTW :Tigger: is a rotary guy




2muchpwr, that was a nice vid and you really need some ABS LOL :)

With the power to weight adv you had on a fairly high speed autox course you had a pretty big adv over the more or less stock 7.

hahahahah... that's funny stuff.

Anyway, I have owned two FD's... my most recent one being a single turbo. I love it but I'm eventually going to an LS1. I mean, both are cool for what they are but if you wanna make anything over 400whp (you can make much more than that on an LS1 and still have it be quite reliable... which is something you can't really say for a rotary) the LS1 seems like the best choice. Sure it's a hassle to switch engines but in the long run I don't really see how it won't payoff. I think the intention of the original post was to show that adding an LS1 in an FD won't screw up the handling. It's obvious it doesn't so I can't really see why people are arguing. I honestly do not believe that he came in here to make fun of or put down the rotary... he's just trying to show what an LS1 is capable of because there are definitely a lot of rotary owners who bash LS1 FD's. People who are arguing with him are just coming across as stubborn dumbasses in my opinion (and a lot of other people's, not like the arguing people care...). He said he didn't come in here to flame. His orginal post was just showing how the weight was similar and how the LS1 performed even with a lesser suspension and tire setup. Why can't people just say, "Wow, nice car". People can argue all day about how the LS1 isn't a good engine for the FD but honestly if you're looking at just performance and reliablility (the two things that matter most for a lot of people) you can't really go wrong with an aluminum V8. Again, both cars are cool (rotary and LS1) but in their own seperate ways.

Nice car! Can't wait til I get my V8 in!

The point is that the LS1 does no harm to the already excellent handling but it completely improves the power and its delivery. The fact that the power is more reliable, the car will accelerate hard without winding it up to 5,000 rpm or building boost first and is more reliable with better fuel mileage is just icing on the cake.


Skid pad numbers only tell you how good the tires are and are to be ignored IMO. Skid pad numbers are not an indicator of a good handling car, though most people would argue until they were blue :icon_no2:

My car with nearly stock suspension routinely sees cornering g of 1.3+ when on race tires. Does that mean it handles better than a car that pulls only 1.1 g? Maybe, maybe not. You can't draw any real conclusions from looking at those numbers.

I agree that skidpad numbers are primarily determined by the tires. Although other factors do come into play. I too tend to disregard them.

I used to have 90 Mustang GT with VERY wide R compound tires. It could post monster skidpad numbers even with its heavy weight, screwed up front suspenison geometry and live rear axle.

it would be nice to see a video of a stock rx7 also on that same course layout to see the diffrence. i dont think its fair to compare a stock fd with 220whp IF running right and most of them dont at this age, with your close to 400whp? ls1fd. the car seems to be very well behaved from the video, given the driver knows how to handle the car also. and i would want to see this same car on street tires doing that same course :). why does a stock fd with almost a full tank of gas weight 2715? i find this hard to belive, a stock r1 should be just a tad over 2800lbs.


oh and, those who argue rotary reliabilty are plain stupid, i belive mazda proved this many times already that it can be as reliable if not more so then a piston esp in 91 with the 787. those who have reliability problems with their rotary car, please get your car to a good mechanic and have them fix teh car for you. a 2 rotor turbo with over 400whp can be plenty reliable, with everything else breaking on the car LONG before the engine does

plenty reliable as in 50k miles at the MAX? As in having to run premix in every other gas tank so it smells like a lawn mower? As in having to warm the car up or else it doesn't run right at all (like won't drive at all. the few 400whp rotarys i've seen dont' just start up first try, especially when it's cold out, and run smooth. there are plenty of high performance 400whp LS1's that run like civic engines as far as that goes). I don't see how you can say that people who argue reliability of high horsepower rotarys are dumb... I'd be willing to bet that many more 400whp 2 rotor engines blow before 400whp LS1's. Wanna take me on? And ya, the stock RX7 vs high horsepower V8 isn't a fair comparison but I don't think he even got on here initially to argue that. I'm PRETTY sure that if you read the first post he just talks about weight and handling and it's not until people start arguing that he brings up the times. BTW he said it's on street tires... crappy ones at that. I don't hate rotary's by any means (considering I own one) but I don't really understand what the arguement is about. IT's very similar in weight and obviously doesn't destroy the handling.

But I'm still up for the bet if you are.

Sandro is indeed a great guy and a pretty good driver. Haven't seen him in a over a year, the last time I went to a E-town autox. His daughter is a good driver as well. Last time I spoke to him, I believe he said he had a DP on his car.

The weight numbers are impressive on the LS1 vs. 13B. I always wondered however if the weight on the LS1 was centered higher(as in from top to bottom) than the 13B. If if is(which I dont know) it cant be noticeable if people are saying the handling is unchanged.

Good thread!

I have a hard time believing the weight CG isnt higher with the ls1 vs the 13b. However, how much higher is the question. If people cant tell the different handling wise, I'd venture to say that the entire mass of the car contributes enough to placing the CG of it that the very small change in CG of the actual engine used doesnt affect it much. Be interesting to measure it though...

god dude, what are you talking about?


and about the rest of this thread: why are we comparing a stock R1 to an LS1 FD that has 100 more rwhp? i think of any two cars that are on the same chassis, the one with 100 more whp is going to be faster...