RotaryResurrection

iTrader: (8)

Sounds like you've made up your mind. I've offered you an "out" that can get your rotary back on the road for a couple of grand, with no real custom work required, but if it is really that big a decision for you then you should probably move ahead with the swap.

Me personally, I'll leave the 450lb 6 liter in my truck where it belongs, and even if I have to swap/refresh a rotary in my 7 I can have it out and disassembled in a couple hours' time with a few basic hand tools. I plan to mod my truck more, and I know that if I ever tear that big bastard of an engine up it will be a lot of work to get it in and out, and quite expensive to get it gone through.

twokrx7

iTrader: (1)

Face it, the boosted rotary is not as robust as we would like it to be. I agree that a well setup car properly tuned for racing and properly cared for can last. However, most folks that think they know rotaries don't really know and it's easy to get just a hint of detonation and chip or break an apex seal. A track rx7 is easier in my opinion than a street rx7, as you can afford to do certain precautions like using race gas for extra protection against detonation. You still need to avoid a common engine shredding fail mode of boosting a motor that's been sitting and heat soaking with an iat sensor reading way hot but as soon as the car is boosted with a cold IC the air temps are way colder and the air is way denser than the ECU knows so it leans out to the moon and boom.

The LS1 eliminates most of the Rx7's engine shredding tendencies. About all you need to worry about with an LS1 is coolant and oil.

Mahjik

iTrader: (1)

After going through my project, I've changed my thought on these engines. My advice is to treat the engines as basically disposable. However, to do this, you need to use basically stock motors (no porting, no milling for 3mm seals, no oil/coolant passage porting, etc). This way, it makes it MUCH simpler when/if an engine fails as you just pop in another stock motor and go. If you are rebuilding yourself, you just locate good used or new stock parts and rebuild. It also makes it a little less heartache when or if a motor fails.

If you aren't in competition with the car, porting and such shouldn't really matter. If you are competing, then an LS1 isn't such a great idea as that's going to throw you into an AutoX/NASA class with all the big dawgs with unlimited budgets.

RXKarma

Does anyone else think that with 13k worth of mods he should be making more power then 331rwhp? Something Doesnt add up here

charlies7

iTrader: (4)

Stick with a rotary, if the motor is built solid and the tune is spot on then there wouldnt be an issue. There are many more qualified tuners out there that can do much better. You just need to find them, most of the time there not even on this forum. Also you should try rebuilding the engine yourself, there are many DVD's and porting templates that you can go off of. That way when you get it down itll only cost you a grand to rebuild rather than 4k from a shop. Plus you got to love the 8.5k redline. Who needs torque anyways?

charlies7

iTrader: (4)

Yes it does, he is still on the sequential system for one, his engine isnt ported. Also if the car is set up right for his racing habit I can easily see it being 13k.

3rd Gen Jeremy

That's an interesting point of view Majik.

As to your comment about the classing, I'm already in SM2 which is pretty much unlimited budget. The difference would be that if I swap, I would be in XP which is also unlimited budget. The only difference for me would be a full interior vs a gutted one.

For the guy talking about making more power with 13k, I have the capability to make upto 500 hp with my fuel system, ignition system and all the other reliability and performance mods that I've done. The bottleneck is the twins. I was going to upgrade them to a GT35r this winter but I guess my plans have changed.

I've been very careful with this motor and done all the reliability mods, I monitor water temp, oil temp and afrs like it's my job. I only use 20w50 and I never drive the car in the rain, except at the race track. I've got the SS oil metering lines and I've cleaned out the OMP jets when I put those on. I've poured my heart and soul into this car for the past year straight and now the motor is gone. Most likely due to bad gas or a faulty OMP. I just don't know if I can go through that again. don't get me wrong, I love rotaries but I need something that can put up with what I do with the car on the weekends.

Mahjik

iTrader: (1)

Well, I'm not necessarily referring to the difference "for you" specifically, but the difference in competition (i.e. do you care to have a chance to win or not).

3rd Gen Jeremy

You didn't just say efficiency and rotary in the same sentence did you?

ihavetwins

iTrader: (5)

ls1 is the childs way to go 13b is the way 2 go

Narfle

iTrader: (16)

Its cheaper

3rd Gen Jeremy

it's cheaper to sell my parts and do the swap

I need some sucess stories. I need to know how long I can expect to run a ported motor at just above 400hp from Gotham Racing. I've already stated that I race the car all the time. I want to hear from someone who has done what I'm talking about doing without popping their motor every year.

Can anybody supply me with those?

M104-AMG

iTrader: (8)

I run a stock motor with 4x850cc injectors, PFC, stock sequential setup, an SR Motorsports SMIC., and all reliability mods.

I asked Steve Kan to tune me for reliability, so after 3-years of monthly autox, and a minimum of four 2-day driving events a year (some as instructor), I haven't had anything go bad with the engine.

Last dyno was about 325 RWHP.

I don't think with the stock turbos and no porting I could get 400 RWHP reliably, however with a nice single or a BNR setup, I bet one could attain a reliable 350-375 RWHP.

:-) neil

3rd Gen Jeremy

Thanks,

Who built your motor? How do you feel about porting? I do all you said plus I drag race it. I really don't want to lose the rotary but it is more expensive to go that route and less reliable so I need to feel reasonably confident that I can get at least 4 seasons out of the car.

I'm thinking about going with the Stage 2 port from Gotham with the oil and coolant mods, 3mm apex seals and the upgraded seal kit. Any pros and cons that I could hear about?

rotaryinspired

iTrader: (3)

If it were me and I wasn't building my motor. It would go to crispeed or CLR. Talk to those guys first. Talk to several builders and see who you feel comfortable w/. Nothing wrong w/ Gotham they seem to be a very reputable shop, but I again would use the 2 mentioned above if I didn't build my own.

Good luck.

M104-AMG

iTrader: (8)

My motor is a fairly new factory Mazda that had 1200-miles on her and was put in storage for about 5-years before she was installed. It was NOT a Mazda reman.

However, should she ever pop, I want a reliable 400-450 RWHP, so I'd probably go LS7 . . .

:-) neil

Narfle

iTrader: (16)

You ARE fooling yourself.

cost of prof rebuild without touching car: $6-7k(and thats pretty rediculously high)

cost of LS1 + T56 + subframe and swap without any help : $6-7k(and thats pretty rediculously low)

not to mention youll have to hack your car to pieces unless you wait for jimlab's cradle through dynotested.

lt1rx798

the guy who helped me build my car has a fd with an old style small block with an lt1 intake custom fitted. he also has two sub-frames that can be swaped at any time. he can put the rotary or the v8 whenever he wants..... granted, he is a freak of nature, but i have seen him driving around with the rotary, then within two days, his car is loping.

he built his own cradle, and he is a mechanic, but im not. i have done all the work on my car...with his guidance, and i put the motor in my car by myself the last time. i dont want anything to do with the rat-nest of wiring and vaccum lines of the rotary, much less having to deal with the "disposable" aspect of it.

please understand; im not dog-ing the rotary. it's just not for me. if it's not for you, than the decision is clear.

lt1rx798

i do agree, that it would absolutley be cheaper to buy a v8 car that is already running.......but if you are considering this option, you still need to do your research so you know what to look for. there are many butchered installs out there.

Troux

iTrader: (6)

I got a good condition, well-running 13B pullout I'll sell you for $1500 w/ auto tranny, ECU, turbos, bone stock its whole life.

By the way, if you want REAL advice on the LSx swap, head to the Other Engine Conversions forum, or even better, v8rx7forum.com. I've seen 4-5 different cases of LS FDs that have had their car corner weighed, and EVERY time, the car's weight percentage actually became closer to 50/50 than stock. Not to mention all these guys with the huge FMICs or even SMICs. With an LS2 you're looking at more than 330 WHP. I've seen them put down around 370 stock. If you're swapping one in, it's pretty much a given that you're putting on (at the bare minimum) an intake, headers, and full exhaust. You're looking at 400 WHP before you're tuned.

wthx100

It's very easy

Do you want to be a mechanic (rotary)
Or a driverls1

IRPerformance

iTrader: (41)

Just do what makes you happy. Its your car. And yes I do think rx-7s have no low end. My 476rwhp gt35r fd barely made 350 torque. My cobra on the other hand makes 500 under 3k rpm.Different animal yes, but its completely redefines torque coming from a rotary. If you go to Gotham, make sure Alex or George build your motor.

FD3S2005

iTrader: (11)

sell the car if you think about going ls dont ruin a good car.... also pettit racing engine does hold really strong.. a friend of mine has a motor by pettit and he drifts his car which is still holding strong and he has a ic with no ducting and still runs great...

pomanferrari

iTrader: (1)

I agree with this. Treat the motor as wear items like brake pads and clutches. I'm on my 3rd motor. First two were all coolant seals and housing warping. Each lasted 50K at 13-14 psi. The third one I'm running with Evans and aux electric water pump to keep the engine cool after shutdown.

Each motor was a Mazda rebuilt at $3K with labor being my own. Total each time $4K. So for the price of one v-8, I can get 3 motors over 150K. A v-8 will last that long but you're going to be constantly tinkering with it rather than driving it.

XxMerlinxX

iTrader: (2)

I really tormented myself over what to do once my engine was blown. It came down to all the things that nagged me about the rotary.

1. No torque. Low to mid-range, it's just not there.
2. 3k hesitation. I didn't enjoy the dip I got every once in a while. Definitely didn't enjoy the bucking.
3. Vacuum Tubes. The rats nest is a pain in the *** no matter what you do to it.
4. Transmission. The car really should've come with a 6 speed.
5. Parts. If something broke, I'd have to wait on the parts to come in, there's nothing readily available.
6. Repairs. Nobody near me really knew how to work on it. I don't have the space/time to learn everything I need to know so that I could work on it myself.
7. Coolant Seals. I was always worrying about them.
8. Apex Seals. I was always worrying about them.
9. Tuning. If the tuning isn't spot on, there are plenty of more problems that can crop up on you, many of which lead to a new engine.
10. Boost leaks. Not always easy to find.
11. Boost problems. There are so many and lots of them have the same symptoms. Can also lead to a new engine.
12. Heat. You could use the engine bay as a pottery kiln if you wanted to.

And then it also came down to all the things I hated about the V8.

1. It's huge.
2. It's American. Nothing against American products, but this is a Japanese car. No, not just a car, a legend. Just doesn't feel right putting that in there.
3. It's redneck. Dag gum bo, whatchew got in thur? Won of them thar camaro engines! YEEEOOOOP!
4. It has a deep exhaust note as opposed to a high pitched japanese sound. Not that I really enjoyed the sound of "God's Chainsaw", but still.
5. It'll attract just as much attention as the rotary, but probably more so from the domestic crowd.
6. I have to learn about conventional piston engines again.
7. Now when I'm at the gas station and someone asks me if it has a V8, I'll have to say yes.
8. It doesn't rev to 8200rpm. At the moment it doesn't, maybe some day it might.

But then I contrasted the two.

1. The V8 has a lot more horsepower in stock form than the rotary.
2. The V8 can make a lot more horsepower in a more reliable way.
3. Won't take much work to get it into the 400-500hp range while staying N/A.
4. Will be able to use 150hp shot of N2O to get it into the 600hp range.
5. Cheaper to work on.
6. Easier to work on.
7. Parts are a lot easier to find.
8. Weight distribution won't be off by much, if any at all.
9. Torque.
10. No Apex seals.
11. Will run for a lot longer than 100k miles before needing a rebuild.
12. Good gas mileage.

So it basically comes down to what you want to use the car for. I'm mainly doing it for the reliability and the power/cost ratio. I fully intend to get another FD some day and keep it in stock form, but until then, I'll have this. I understand the argument that what makes a rotary unique, is the rotary, but that's simply not the case here. The FD is unique for many other reasons, it's handling, it's looks, it's feel. The engine really is only one part of the whole and I love the whole of the car, not just the engine, so I wanted to keep it instead of getting something else.