shadycrew31

iTrader: (6)

Its not that hard to rebuild a renesis... I highly doubt this will become a common thing among 8's maybe in 2025.

neofreak

iTrader: (1)

I'm not sure what you mean by "up top" but typically the turbo on a 13B-REW or 20B is located right at the exhaust ports -- I'd say that is pretty low.

Piping doesn't weigh a whole lot, neither does the intercooler.

shadycrew31

iTrader: (6)

I could most likely rebuild 3 renesis motors reusing the core and still wind up below the cost of this swap.

J8635621

iTrader: (10)

+turbo+all the other supporting mods to be at a similar power level = more what I was getting at
edit: I said contemplatable not commonplace

olddragger

iTrader: (3)

nothing wrong with an ls swap. Very sweet engine.
I am an old chevy fan -since my 1st car was a 57 chevy convertible in 1965.
Great engine.
ls motor in the 8 would kinda remind me of a small vette.
I just saw a very well done ls swap into a s2000--had solid mounts and didnt even vibrate.
OD

cavemancan

I am having trouble understanding what you mean...

So if they have tons of power in handles great?

I am betting I won't complain afterward as well but the main reason I fell for this car was the handling and Feel of the car. So I want that sorted before I initiate.

cavemancan

In my present condition I have low compression @ 90K miles. I may have the possibility to get my motor replaced and I am trying to persue this route but take the following into consideration...

I want forced induction. The forced induction of choice for me is the Pettit Super Charger which would cost about $8300 with installation. The LS swap for the Rx7 guys costs almost the same not counting the engine and Trans. So for a little more ($3 or 4k) you can have...

(Crank HP)

LS2 - 400 HP/400 lbs/ft

Compared to:
13B Renesis + SC - 360 (ish) HP/250 lbs/ft

My brothers are chevy freaks and the oldest is a 20 + year ASC master certified mechanic so I can see alot of savings in labor especially if a kit is fabricated including a kit for the electronics. I might be able to drop the cost significantly. Hell I could give my brother $1 or 2k and still save. Especially if we find a wrecked GTO.

If mazda approves my engine rebuild I could sell the engine and recoup more money this way as well. So it's not a crazy dream. This could turn out to be a cheaper solution for me. Now I have to satisfy my need for handling before I approve the project.

nycgps

iTrader: (1)

the 7s community have been doing LSx swaps for years. but they *still* have yet to find a cost effective way for the swap + the car is never the same. some of them will tell u it handles the same with 2-300 more horse, but they're just telling u a big fat lie or they got no feelings to begin with.

that explains it all.

it will never be the same.

if mazda says ok to the engine then yeah u can sell that to get some money for ur project. but lots of LSx people gotta sell their car in the end cuz the cost almost always gone out of their projected budget even when they first said "I got this help and that help and engines are everywhere cheaply"

dont get me wrong, I think its a fun thing to try. but prepare to spend a lot of money & time.

cavemancan

The stock turbos...Most upgrade those parts and many place them infront of the engine where the Rx8's stock battery location (up top?). Perhaps I could have used better choice of words then "up top". Slightly above and forward from the center of gravity of the engine bay?

I wish I could add one of Alfy's classic pics in here to make me fall out of my chair laughing and depict what I am trying to say...LOL!!

My point is a 20B with a turbo and an LS swapped engine would get relatively the same hit in weight and balance. Based on the numbers listed for the 20B...70lbs heavier...Perhaps worse then the LS? I guess it depends where.

cavemancan

I can appreciate how everyone feels about the subject cause frankly I live on both sides of the coin. With that said I need proof that the Rx7 builds ruin the car. I also need proof that the LS swap will make the car better. So far the research I've collected implies the handling will be affected only slightly and can be corrected with basic adjustements of weight and suspension.

I bet no one would question a 20B swap...Hell, I am guilty as charged in this regaurd...That is untill I fould out it can weigh as much as 770lbs in stock turbo form.

cavemancan

I think this is the first time one of my threads wen't past 2 pages without dying!!!!



Jynx!

cavemancan

My oldest brother had a Chevelle SS fully built motor...The middle brother wrecked it (flipped it on it's roof) and walked away with a scrape on his knee.

My middle brother had a 1978 Nove with a 1990's transam motor in it...The oldest brother sold it without telling the middle brother. I think they are even now...LMAO!!!!

cavemancan

I have another good question...Unless I am completely getting this wrong then it's a stupid question.

What if I add a Dry sump oil system? Could I lower the engine a little more? I believe at that point the oil pan is no longer necessary (or could be made smaller) which would enable me to lower the block.

Anyone have pics of the side and bottom of an LS2 and an LS3/7 with and without the dry sump oil system?

Winning 8

All I want to ask is how many guys here have a sun roof. You know the sun roof and the motor is like 100lbs and 3' above center of gravity that is worst then a LS swap...

olddragger

iTrader: (3)

what i meant on the ls rx7 swaps was that if the power was not being used (every day driving/cruising ) then the car handled very very closly to oem. the 2nd gen actually handles it better than the 3nd gen. I have yet to see a ls swapped car go back to the rotory engine.
Good friend of mine does these swaps professionaly. He can provide the car and swap with a/c, power steering etc for around $15. Thats a basic build.
You can easily put $8K into a fi build for the 8.
Dont get me wrong --i really like the rotory and its driving characteristics. We have a very unquie car. The only one of its kind in the world.
Its not the oil pan that will be the problem. The problem will be the electric steering assembley and maintaining its function.

Oh by the way I traded that 57 convertable for a 55 2 dr hardtop and then dropped the aluminum headed/oval ports/12:1 compression (burnt up a set of plugs every week!) 396 with a 2:20 4 speed munchie trans with positraction 4:11 diff. mid 12 sec car in 1966. On street tires! Just couldnt stop the damn thing. Awful brakes.

neofreak

iTrader: (1)

No, they don't. It seems to me that only the 13BMSP turbos get put in front of the engine. 20B and 13B-REW big singles are still typically right next to the exhaust ports. I guess it could be an RX-8 thing, but I have never seen anyone relocate a turbo to the front of the engine on any RX-7.

Plus they aftermarket turbos still typically weigh less than the stock twin turbos.

It sounds like you already made up your mind, so just do it, you don't need to justify it to the forum or anything.

cavemancan

If I am wrong or right in the end does not make a difference. I can't argue the point since I have little to no experience so I won't.

On the other hand I have not made up my mind or else this thread would be dead. I did post a few more questions/senarios above that I would love answers to. So the research continues.

I will be easily agree for or against this build if there is proof and I will continue looking untill I get bored or get the answers I want.

Red Rex

iTrader: (1)

The Chevy small-block V8's are amazing. You would think ANY car with a 428 cubic inch engine up front would have horrible weight distribution. The C6 Z06 has perfect 50/50. Fully assembled the 6.2L LS3 weighs just over 350 lbs. The 5.7L LS1 was actually physically more compact than Ford's 4.6L SOHC V8.

These are all-aluminum pushrod small-blocks. Not a quad cam 50-valve-per-cylinder time machine. They are small, light weight, and because of their displacement make ridiculous amounts of power and the only way a naturally aspirated RX8 could get a faster quarter mile time against even a stock 3600 lb F-body is if you pushed the RX8 off a cliff.

If you throw a GM LS engine into your 8 you're definitely going to need to beef up the drivetrain. Corvette's will snap half-shafts like nobody's bizniz. Also the RX8 chassis has a lot of wheel hop when dealing with high power. Wheel hop = snap crackle pop = $$$

GeorgeH

iTrader: (2)

I'll back up OD and say that it's my understanding that the RX-7 guys have proven you can make a good handling car with an LS engine swap. But be prepared to sort out spring rates, roll rates, wheel sizes, etc. to make it all work. This is harder than it sounds, at least the first time around.

Having said that, I watched an LS engine-swap RX-7 run at a ProSolo event a month ago, and then watched the Corvettes run, and gee, they sounded the same, performed similarly, and I found myself thinking, why not just by a Corvette? How cheap are C5 Z06s these days?

I know, it's not the same car, many people can't handle the idea of being seen in a 'vette, and others like the challenge of the swap (I fall into this camp, up to a point, myself). But I'm just sayin'....

Red Rex

iTrader: (1)

C5 Z's run ~$25K with about 40K miles on them these days. The key to the C5 Z's is the transmission gearing and the suspension. Yeah leafsprings, but they allow the vette to sit lower than other type of suspension would.

dmitrik4

iTrader: (5)

i guess it depends.

2nd gen RX-7...yeah, i hear you.

3rd gen RX-7...b/c the 7 is a much better-looking car.

RX-8...4 seats!

personally, i'm still looking forward to an LS Miata.

Winning 8

FC is a direct copy of a Porsche 924.

Snrub

That's part of why GM has stuck with a pushrod engine for the Corvette. I read an article in C&D a few years ago and GM fully admitted they were leaving ~10% power on the table with the Corvette by sticking with a pushrod design. (not that 430-505hp leaves much to be desired) The advantages are that it's more compact, lower, lighter. This means the 'vette can have desirable performance traits and have a low hoodline. They somehow manage to get decent fuel economy out of it too.

Red Rex

iTrader: (1)

The fuel mileage is related to the weight and gearing of the car. Chevy pulled a lot of tricks up their sleeves to get the Corvette as light as possible. Believe it or not the Corvette is actually geared towards top speed, not acceleration. So the engine falls on its face (~1300 rpm) on highway speeds around 60 mph. My dad's C6 Z06 has about 650 bhp and has recorded 27 mpg before. Normally this would lead to slow acceleration times but because there is so much torque it moves through the rev range like its got a 2 lb flywheel.

cavemancan

I love vette's but a dedent used Z06 will run between 25k to 55k depending on the model year and mileage.

For $15K I could possibly get the same performance (to be determined) for much less money, weight, better mileage due to weight, and I get to keep my car...I've grown a bit attached to her. LOL!