Ok As Odd As It May Sound, I Know Its Been Done, And I Know Its Better To Get An 240sx, But I Have A2nd Gen 1990 Rx7 Non Turbo, And I All So Have On Hand A Sr20det Engine /trans,.....my Question Is This, Is There A Engine Adapter Swap Kit Or Is To Be Made By Me, Thats Not A Prob. But If There Is A Kit Out There, It Would Be Easier On Me.. And If Any One Has Done Tis, Like Tony Angalo Had At One Time, Drop Me A Line Of Information That I Could Use,...please,

 

no kit. your going to need someone who can do a lot of fab work.

 

Why not go 13B-RE? or 20B? SR20's aren't the greatest, if you're going to go Nissan, at least do the RB25

 

And what's wrong with SR20's??

I have one, and I love it.

 

it's fine in a Silvia, but RB's have better power potential. That's why I personally like the RB25 better.

I just have the opinion of a purist, that RX-7's should be kept rotary, espcially if you can drop a 20B in

 

That's fine and dandy if you don't care that the RB25 adds a minimum of 150lbs to the weight of a silvia, and is at least $1500 more expensive for the initial installation. It's power is also over-rated as you need basic bolt-ons to get the rated hp/tq. And as a friend of mine who lives in Japan says, if you're going to go RB big, just go the 26 and **** the bullshit.

In my opinion an LS1/2/6/7 is superior to a 20b in everyway except revs, so for someone who isn't afraid of pushrod technology, it's definetly the ideal way to go.

 

yea nothing wrong with the sr20det, i had one and still miss it........ the thought of dropping one into the fd had crossed my mind i won't lie haha rb's are nice but parts are alot more expensive for them, so for most people its really not the best way to go.

 

Also it's more customizing that needs to be done for the RB's to work. Trust me, if I could drop an RB26DETT in the FD, I would in a heartbeat. But alas, the amount of fabbing and money required, and still not have a smog-legal car.... Yuck.

I love my SR20 powered S13, and I know I'll miss it after I sell it. It really does deserve the raves people give it. It's a tough little motor that takes to mods very well.

 

really? I've seen a S13 that had an RB installation done, which was pretty much a drop-in for his car, maybe a small bit of fabbing, but nothing major.

I'm just not really seeing pistons in an RX-7, but specifically how is the 20B worse than the LS1/2/7? I've never seen a head-to-head comparison so I wouldn't know.

 

hell yea, they can take quite a pounding, its an amazing lil motor

 

How about gas mileage, parts, and longevity? Oh ya and easier to find people who can work on it. There ya go.

And the RB25 you need to use a skyline crossmember, or a custom one, custom driveshaft, and mounts would make it fit ALOT better. The RB20 is alot easier to swap, but not worth the effort over the SR20 unless the inline 6cyl noise is what you need.

 

longevity is all based on how you take care of it, so that's not really a factor.

When you buy a rotary, you sort of give up a couple of things, gas mileage, parts support, people who can work on them. That's the price for being part of the minority. But you learn to deal, or you buy a piston engine if you can't deal. I don't even see how gas mileage is an issue, you can always tune a car for what you want it to do, especially since you're probably getting a standalone with either engine swap. The point is, I haven't seen any substantial reason why a ROTARY owner would want to go with the LS1/2/7 over the 20B. I can give you some reasons why you would want to go 20B, mounting the engine gives better weight balance, 20B NA's are one of the best track cars around. I guess if you're all about the drag, the power-to-weight of the LS1/2/7 may be higher and therefore better, but to each their own.

 

From your post, it sounds like you believe the LS1/2/6/7 throws the balance of the car out of wack. There've been plenty of FD's with the LS1's that perform at the same level as your rotary powered FD's in terms of handling. So I don't know why you think that a V8 powered RX-7 is only built for drag. Maybe you mis-spoke? I don't want to put words into your mouth, or assume you meant something, when you really meant something else, so please tell me why you think an LS1 powered FD is only going to be good for Drag? Why can't it compete on a track competitively with a rotary powered FD?

 

I never said it throws the car out of wack, I just said the rotary's engine placement makes it better for handling because of the front midship design.

Let's put it this way, no race manufacturer will ever produce a piston-powered RX-7 that corners and handles as well as RE Amemiya's 3-Rotor NA FD. That's not to say that the piston-powered RX-7 will be bad, but how good the rotary-powered FD is. It laps the Tsukuba I think in the 58 or 59 second range, the same time as Skyline's with 200 hp more than itself. I've never seen any piston-powered FD hang with GT-R's like that before, maybe you have? Like I said, I don't know much about the head-to-head comparison between the two and only have hearsay and opinions which don't make great foundation for arguments.

 

I've seen magazine articles with LS1 powered FD's pulling a 1.07G on the skidpad, how's that for arguments?

I've heard from Rotary heads who have driven LS1 powered FD's on the track and say they handle just as well if not better than their rotary powered FD's. How's that for arguments? Where does your argument come from? Besides your thinking that a V8 is inferior in weight balance to a rotary in an RX-7, where are your facts to back it up? The FD has been weighted and balanced with these engine swaps, and if done properly, still retains it's legendary handling characteristics.

You probably won't see any race manufacturer put a piston engine in an RX-7 because of all the purists who would cry foul on it, like this section of the forum gets ALL THE TIME. Spend some time in this section of the forums and read up on what owners of this swap have to say about their cars and the unchanged handling, then come back and tell me what's so bad about the conversion.

 

V8, longer, mounted over axle, Fact, or at least as well as I can gather from the pictures in the V8 forum, the front of the engine protrudes in front of the strut towers

Rotary, smaller, behind axle, Fact

Laws of Physics state, the further the arm is away from the center, the more torque the end of the arm receives. In this case, it translates to a higher polar moment in V8 Converted cars. My "facts" for this is Sir Isaac Newton himself, you might have a problem asking him, since he's been deceased for quite some time.

In the V8 forum, an owner corner weighted his car, turned out to be 54/46. Stock FD's weight, listed by Mazda was 50/50.

When you make handling comparisons, questions have to be asked. What type of tires were the LS1 owners using? What type of tires were the 13B owners using? I don't like skidpad comparisons, because if you alter the tire spec, you can increase the G-force. With a bit of lightening, My FC can exceed 1G with the street tires I put on, and that's with a McPherson Strut suspension. If I had R-Compounds, 1.03 would be attainable. If I had race tires, 1.08 would be easy. Does that mean my FC handles better than a LSX/13B/20B FD? Of course not.

I'll concede that on the street, the V8 swap is more desirable for some due to the broader powerband and increased torque. Since it's only an 8% spread, some owners probably don't notice the difference when they go from one engine to the other. On a road course, or a downhill, where I like to do my runs, I like cars with less torque, higher redline and lower polar moment.

There's nothing bad about the conversion, I just didn't like the authoritative way you said that the LS1 was DEFINITELY better than the 20B. For me less torque, makes the car easier to handle through the corners when modulating the throttle and the lower polar moment decreases the risk of a spinout due to bad weight transitioning.

 

skidpad = tire stickiness

not to say that thats not impressive or to say that LS1 messes up balance, but skidpad comparisons suck. also, rotary weight distribution will almost always be better (if only marginally) that piston engines

 

To add something from the horses mouth on FD weight balance here is what I have found:

Stock FD 13B-REW with stock twins/downpipe/cats/midpipe isn't that light. An n/a 13B is very light when you get rid of the factory exhaust/cats and cast iron exhaust manifold.

My LS1/FD conversion (no a/c or p/s) was 49.5% front and 50.5% rear with a full tank of gas and me in it. Being all aluminum helps the conversion and having a 150lb transmission and dual mild steel exhaust helps balance the car as well. An LS1 with all accessories/engine wiring harness, ECM, flywheel/clutch complete from intake to oil pan weighs about 480lbs. Remove the a/c and p/s and you have shed about 30lbs of weight. Add a lightweight aluminum flywheel/clutch setup and you have shed another 15-20lbs or so. Making the stock 13B-REW and an LS1 with these "deletes" closer in overall weight.

My cross weights were within 1lb of each other which is about as good as it gets. Saying the LS1 conversion messes up the handling is inaccurate. Putting all iron V8 in there will certainly produce less than stellar results for handling.

In SCC Mag "Ultimate Street Car Challenge" the car averaged 1.09g's on 285/30/18 MichPSCup tires (full tread depth) R compounds. 1.13g's in one direction and 1.06g's in the other done professionally on a 200' skidpad.

What could cause such a huge difference you ask? Come to find out my custom subframe was completely cracked and actually separated at the front lower A-arm mounting point. Not a good thing for handling or my well being (life/safety) going 150mph+ down straightaways and 100mph+ into some corners.

Car would've pulled 1.13g's average which ties the highest number they have ever tested (they were on Hoosiers I believe) on a Larmier (sp?) tube chassis FD (13B-REW turbo) powered kit car. Shoulda coulda woulda.....

Subframe has been replaced and all is good now.

Here is the article on the USCC writeup:
http://www.ponycars.net/scc.htm

I also believe that a single turbo 13B-REW with lightweight downpipe/exhaust, no a/c and other tricks would handle a bit better than an LS1 conversion since it would be more like 48% front/52% rear and be down in the 2650lb range. Will 99% of the driver's behind the wheel be able to make it produce faster lap times than a similarly prepared LS1 conversion? ... probably not! They will be very close.

 

You know what, the argument is stupid, both routes have their pros and cons, but are equally viable. I just wanted to point out that there is no definite route that is better than the other.

49.5/50.5? Nicely done job, gnx7, you think, with these tricks, you can get a 20B to 48/52?

 

Its as if the guys arguing for the 20b dont realize the 20b is heavier than a 13b.

All the weight comparisons I see are ls1 vs 13b-rew, yet they are arguing about the merit of the 20b.

Whats the weight like on a 20b conversion?

 

ok here goes.... i'm very pro rotary. but your kinda out there with this comparsion so i'll be out there with my comparsion too. this car that RE built, yes i would completly nut if RE gave the keys to me but lets say for a sec. you took the 20B out and put the LS1 in the same car. now i'm not going to go into the whole weight thing b/c its be covered over and over.

now if memory severs me right that car had 360whp and i don't know what the conversion is for the troque. now 20Bs are heavier then a 13B which an LS1 is comparible to. so lets just say for kicks(i don't have hard numbers) in NA20B form they are around the same weight. handling is not effected so where talking power delievary. that 20B could REV up to 9K(even though is was in a 10K challenge) which most of the power and torque was in the last 25% of the RPM band. now in comes a LS1... a swaped LS1 with all the swap goody produces around 325whp @360ftp of torque sorry if wrong its been a while since i've looked up the numbers. running anyware from low 12's to high 11's one a stock LS1 motor and trans! now drop this engineand tranns into that RE chassie now you have 75% of your torque at 2500 RPMs and it just pulls all the way to redline. I would put money and a lot of money on that chassie with a LS1 in it knocking down that time to 57 maybe even 56 secs. with a hell of a surprised face on MR. RE. anyway what i'm trying to say is its the purist thinking that gets in the way of giving LS1 swap rx7's their props. a lot of work will have to been done to the 13B to run with a stock LS1 in an FD. this is all speculation but i believe heavly in my predictions.


now as for the SR20. i almost kinda want to do a SR swap into an FD. i've already seen two done and really doesn't look to damn hard. SR20 can make almost any horse power number that the 13B can. plus they have the reliability of a honda engine.

 

nice

 

Wow.....thread resurrection......can we serious ban n00bs for doing this without a good reason?

Ah...back in the day, I'd argue rotaries vs. pistons...nowadays, I just don't care.

 

how about we ban you for being an *** cuz someone used the search function and decided to post in a thread that hasnt been posted in a while.

Its either: Do a search NOOB! or Quit resurrecting old threads!

SR swap FTW

 

hey, being an *** is well deserved here, since the post did not provide any value to the community, all it does it clutter up the tech section with more old threads that have already been covered.

For example, looking at the 2nd gen section, Vented Hood Thread, it's been gone for a couple of years, however, people resurrected it asking if others had other pictures for newer hoods. That's fine. But when your contribution to the forum is "yeah".....that should at least be grounds for a btiching, second time warning, third time temp ban and foruth time a perma ban. It aligns to spamming threads to build post counts.

If you want the information, search it and read it, but don't go bumping old threads.

I'm sure you'd like it if other n00bs decided to bump old threads for no reason, thereby massively cluttering an already cluttered tech section?

I'm all for helping n00bs that ask questions, but pointless bumps should not be tolerated.

Quit resurrecting old threads! is fair, IMO. Read, learn, move on.

I'll call out people for bans for suggesting the use of the ATF trick as well. It's all in an effort to filter out the bad information so all the good information is there for people to learn and enjoy. Get it?