There was a thread on LS2.com about if we had to choose a 4 banger...anyway...its now become a discussion about RX7/8

so can ya guys clear up some things that are being said:


sorry about the legnth....but i cant link to this section on Ls2 unless ur registered

Thanks for clearing things up guys
-Sean

 

N/A rotary engine can easily last in to the 200k + range. One example is when i bought my rx8, there was another rx8 owner there getting an oil change done on her car. we started talking, and i found out that the car she had before the rx8 was an FC rx7, that had almost 300k miles on it when it died. she said she could have easily fixed it, but she'd had the car for so long, she wanted something different.

the main thing that the FD rx7 had different about it was 2 turbos throwing out a ton of heat, and an inadequate cooling system. And from talking to a friend with a 95 FD, its the turbos that typically need a rebuilt at ~60k miles, not the engine, which typically last in the 80-100k range before needing a rebuild.

the reason that the rotary engine got such a bad rap was because doofs who don't know anything about rotaries would buy an FD, improperly mod it, which in turn leaned the AFR out too much and blow the engine.

And since the FD was an amazing car even when it was stock, every dumas and their grandmother wanted to buy it and then mod it, which takes us back to the doofs improperly modding their car.

mazda has largely addressed the improper modding cause of problems by using the ever-controlling ECU that is the bane of anyone trying to get more out of their car.

 

Thanks dude, ill be sure to post that and give you some credit

 

just to let you know, rotary engines aren't the only engines known to burn oil. BMWs, in fact, are supposed to burn up to 1 quart every 1000 miles.

***edit*** just to add. all engines will burn oil. some will burn more than others. unless you have total seal piston rings with absolutly NO GAP, you will always burn oil. plus, rotary engines don't have to worry about jumping time, bending valves, retainers popping out, etc. etc. there are pros and cons to everything.

 

no ****! thats worse than the 8!

 

My '87 Turbo RX-7's original engine lasted ~150K before needing to be replaced. It was properly maintained and cared for, but was also redlined often. It ran the factory turbo at 10lbs of boost, stock was ~8.6.

The FD ruined the reputation of these engines. Mazda made a few mistakes from the factory, like the extremely complex sequential turbo set-up and all the vaccum lines associated with it. The vacuum lines were rubber, they hardened and cracked under the extreme temperatures. Replacing the rubber with silicone lines addressed this issue. Then there was the cooling issues from a plastic overflow tank and too small of a radiator. Add a larger radiator and metal overflow tank and this was no longer an issue, a downpipe replacing the pre-cat further reduced temperatures. FD's also came without boost gauges, so most couldn't readily recognize the signs that something was wrong before it was too late. Owners generally blew FD engines by running them too lean by adding straight through exhaust systems and either not adjusting the fuel, or having improper tuning performed by a shop that had no clue what they were doing. It's easy to get a lot more power out of FD's, but it has to be done carefully, not haphazardly. If the engine, 13B-REW, is properly tuned, the OEM apex seals in the FD are good for upwards of 500hp.

 

^^^ from what i've read, the fuel system on the FD wasn't up to the task of supplying enough fuel when the car was upgraded, and was the primary cause of the afr going lean, then pinging, then dying. and another way of stating the FD's stock 2mm apex seals strenght, is that they have been shown to be handle around 20lbs of boost.

 

I'm taking it "was up to task" you meant "wasn't up to task."

Anyway, the fuel system on the FD was capable up to around 400bhp, as I recall. But if you added a downpipe, midpipe and cat back, you needed to have fuel enrichment programmed into it with like a S-AFC type piggyback, or at that point start thinking about stand alones because you were probably upping the boost voluntarily.

 

Red Devil pretty much summed it all up in a nutshell. a friend of mine has a 1993 TT RX7 running on stock turbos, upgraded FMIC, Apexi Power FC, and mild suspension work. the car has close to 100k miles and is fuel tuned to run in the low 13's/high 12's. he takes the car for track days (not drag). the only issues he has with the car is overheating (cracked AST (the plastic tank Red Devil mentioned)), cracked vacuum lines (the nest underneath the intake manifold), and a faulty coolant temp sensor. other than those things, his RX7 can pretty much own anything on the road.



that's the only picture i have of him

 

that guy that keeps saying a rotary is a rotary is cracking me up.

As him if all 4 cylinders are the same, actually since you're on a ls2 forum, ask him if all v8's designed from 1980 to today are all the same...

That's a pretty ridiculous arguement he's making. But, for some reason, i picture an ls2 forum to be full of uneducated shotgun wielding hillbillies, so I'm not surprised ha ha ha ha...

(present company excluded of course :D)

 

does anyone on that forum run a APS twin turbo kit on an LS2?? i would love to see some pictures. V8 Twin Turbo...that's wicked.

 

lol...nah, they are biased, but very not hillbillish (lol)...im not sure why they dont get or accept the rotary engine, but then again, this isnt a wenkel site, its an Lsx site...yeah and that guy got flamed by a lot of people for that comment lol

 

I just posted a thread....ill let u kno what they say...i do kno though that there are a few there with single turbos

 

TT ls1 http://media.putfile.com/eboggs-LS1-TT

http://www.ls1tech.com/forums/showth...win+turbo+pics

http://www.ls1tech.com/forums/showthread.php?t=414830

 

http://www.exoticperformanceplus.com...Car.php?car=22

 

Riiiight. And the Otto cycle motor hasn't come anywhere in the past 30 years, I'm sure. <sigh> Materials, people, materials - the metallurgy and the manufacturing abilities of major engine manufacturers have come a long way in the past 30 years, where you're seeing piston velocities in the range of F1 engines in small displacement Honda motors, infinitely variable valve timing, and reliable compression ratios greater than 11.0:1. And let's not forget about diesel technology advancements.

Some people just don't want to learn any more than what they think they know.

 

Just like any engineering tradeoffs, the rotary trades less moving parts for slightly more oil consumption. It does not mean it has to be any less reliable than a piston engine. Actually, I'm more concerned about the cost of replacing things like the AC compressor, alternator, etc than engine repairs. The hourly labor is low on the rotary.

 

^^^
You know, a while back I got into a discussion because I recalled it being around 6.2psi on my 87TII. After a while I just relented because I honestly couldn't remember and went with it being at the 8.6 figure.

Now this is bothering me, so I'm going to have to look it up. It's been years since I had that car.