First Rotary Car

[Ghostcloak]

Hey Guys, I'm hoping to join the rex family quite soon.

I've spotted a RX-7 going for $2,500. Basically, it needs a new exhaust system. Its a '91 coupe, in very respectable condition. All the electronics work, sounds, feels, appears to be in excellent condition (other than major exhaust leaks and a fried CAT).

The car has 144k miles on it though. Last rebuild is unknown. I'm thinkin that the owner knows that the engine might not last long, so she's trying to ditch the car out while its still running in awesome shape...

Just outa curiosity, does this car have a timing belt/chain? I know nothing about rotary engines so you all will have to excuse my newbi-ness (I have read articles on them and I understand the theory of how a rotary works, but still don't have pratical experience working on them to fully understand). Expecting that I would have to replace the engine, what would you guys suggest I could do (I have a maximum budget of 3k to spend on the car after purchase...) I'd really like to do the v8 swap (I know many of you will now hate me for saying that...) since I was orginally going to purchase a Porsche 944 and do a LS1 swap in that, but since I've found out the same swap can be done in a RX-7, I've slowly been debating which chassis I prefer...

However, all in all, what would be the serious opinions on this vehicle, and what would your suggestions be as to how I should approach this opportunity? Any great concerns (possibly from personal experiences) that I should know about that would help me make the right decision here? I greatly appreciate you guys taking the time to help me out here.
^_^

[MBTN]

$2500 is probably a bit much.

[Ghostcloak]

What would you call a resonable offer?

Motor has 144k on it...
Car is in avg condition.
'91 coupe
Needs new exhaust (from CAT-Muffler)

I'm assuming its going to need a new engine soon, because of the high milage. Runs alright. Nothing to brag about, but then really nothing out of the ordinary either or compain against.

[FDTT]

1800USD at the most.

And 3k for a full LS1 swap, well it might get you the motor :P And mabe the tranny.

[Ghostcloak]

Awesome... I'm going to see if she's willing to swap her RX-7 + 1,000 USD for my Probe. I think that's a bit of a fair trade...

[drftk1d]

it doesnt seem like you want a rotary car

[NuTbAgSaN]

hah yeah doesnt sound like it`ll be a rotary car for long...

2500 seems high to me for that car. maybe around 2 is more like it.

[Ghostcloak]

*argle* She swapped her rx-7 for a DEL SOL. >_< Civic only had 110k miles on it though and was already riced up. That guy just got jip'd in my opinion... Sucks I don't have a rex though Maybe later next time guys... Thanks

[drftk1d]

its ok, even if you got the rx7 they would think it was still the probe

[longlivetheZ]

Originally Posted by Ghostcloak

I'd really like to do the v8 swap

Ok...that's a new one to me. I thought putting one of those things in a old Z car was kinda stupid...why the hell would you do it to an RX-7? The RX-7s major claim to fame and most of what makes the cars so great is their balance and light weight...mostly due to its tiny, yet powerful(ish) engine. Putting in a huge V8 engine completely negates this arrangement and would throw the balance of the car off. Why would anyone do this?

Originally Posted by Ghostcloak

since I was orginally going to purchase a Porsche 944 and do a LS1 swap in that

And that's even more wrong...

[FDTT]

Originally Posted by longlivetheZ

Ok...that's a new one to me. I thought putting one of those things in a old Z car was kinda stupid...why the hell would you do it to an RX-7? The RX-7s major claim to fame and most of what makes the cars so great is their balance and light weight...mostly due to its tiny, yet powerful(ish) engine. Putting in a huge V8 engine completely negates this arrangement and would throw the balance of the car off. Why would anyone do this?



And that's even more wrong...

Actualy, thats not quite true.

The 13BT is only slightly lighter than the LS-1, so balance would not be thrown off so much. But what becomes an issue is chassis flex from the torque of the motor. I have talked to people who have doen the LS-1 swap and they love it. There is one fellow who autocrosses his can and it handles great. Often posts low times compared to the othere 7's with rotaries.

[longlivetheZ]

Originally Posted by FDTT

The 13BT is only slightly lighter than the LS-1, so balance would not be thrown off so much. But what becomes an issue is chassis flex from the torque of the motor. I have talked to people who have doen the LS-1 swap and they love it. There is one fellow who autocrosses his can and it handles great. Often posts low times compared to the othere 7's with rotaries.

K...the LS-1, after a bit of research, weighs about 457-575 pounds...the bare 13B weighs, again...after a bit of research, about 200 pounds. How do you figure? 250-300 lbs...JUST motor...not even taking into consideration the torque shift you were talking about. That's a BIT more than a "slight difference"...

LS1 weight: http://www.ls1tech.com/forums/archiv...p/t-70679.html

13B weight: http://www.conversionconcepts.com/13...%20Balance.htm

...for reference.

[Ghostcloak]

Originally Posted by longlivetheZ

K...the LS-1, after a bit of research, weighs about 457-575 pounds...the bare 13B weighs, again...after a bit of research, about 200 pounds. How do you figure? 250-300 lbs...JUST motor...not even taking into consideration the torque shift you were talking about. That's a BIT more than a "slight difference"...

There are, of course, small things you can do to help balance out this 250 lb difference (ie: mounting the battery in the back, etc) I mean, hey, the car may just have to be 60:40 weight ratio'd for it to work, but I mean that's just the price you pay to have the v8 over the rotary. The v8 can dish out more power than the rotary, hands down to that due to its higher potential. If you want a 50:50 car, take as much weight from the front that you can, and if you are desperate for that 50:50 weight, hell, carry some lead in the trunk. It might not even hurt to throw some lead weights in the trunk just as long as the HP:Weight ratio is high enough to have the car do what you want it to. For 1/4 mile times, I don't believe that having a 50:50 weight balanced car makes that much of difference from a car that is 60:40. (there may be a slight difference and i can go into details about those, but I'll go ahead and believe we can all understand what I mean...)

[drftk1d]

Originally Posted by longlivetheZ

K...the LS-1, after a bit of research, weighs about 457-575 pounds...the bare 13B weighs, again...after a bit of research, about 200 pounds. How do you figure? 250-300 lbs...JUST motor...not even taking into consideration the torque shift you were talking about. That's a BIT more than a "slight difference"...
:

a full acessory 13b turbo engine (turbo, manifolds, ps pump, ac, etc) weighs just slightly less than a full acessory LS1. remember that the 13b rotary engine is cast iron and the ls1 is aluminum.

Originally Posted by Ghostcloak

There are, of course, small things you can do to help balance out this 250 lb difference (ie: mounting the battery in the back, etc) I mean, hey, the car may just have to be 60:40 weight ratio'd for it to work, but I mean that's just the price you pay to have the v8 over the rotary. The v8 can dish out more power than the rotary, hands down to that due to its higher potential. If you want a 50:50 car, take as much weight from the front that you can, and if you are desperate for that 50:50 weight, hell, carry some lead in the trunk. It might not even hurt to throw some lead weights in the trunk just as long as the HP:Weight ratio is high enough to have the car do what you want it to. For 1/4 mile times, I don't believe that having a 50:50 weight balanced car makes that much of difference from a car that is 60:40. (there may be a slight difference and i can go into details about those, but I'll go ahead and believe we can all understand what I mean...)

with the ls1 swap the balance is slightly thrown towards the front of the car and the center of gravity is higher (unless you do serious cusxtom fabbing, the 13b mounts crazy low in the engine bay compared to other engines), but its definietly not going to be as bad as 60/40.

i think youre going about it all wrong though, i think you should drive the car around as it was designed for a while at first (and try to drive the turbo rotary as well) then make your decision to swap. I think people misunderstand the point of the engine; its not a LS1 or LT1 or 2JZ that makes tons and tons of power. the advantage is that its a better option at lower power levels, like would you rather have a 500 lb v8 in a 2700 lb car making 350hp or a 400 lb rotary making 350 hp in a 2700 lb car? OF course the 13b has its limits (i would say the potential is somewhere between a japanese 4 cylinder and 6 cyl), the most ive seen from a 13b was 900hp, and ive seen 700hp ones as well, but it does not make a good street motor at those power levels (great race motor though). sorry for a long post :P

[drftk1d]

another thought: why not just buy a rolling chassis and save you the trouble of having to take out all taht bullshit from the car?