rotary VS Subaru??

Dairdevil9 · Post by **Dairdevil9** » Sat Oct 23, 2004 8:52 pm

I still can't decide which motor to use in my buggy. I want at least 250HP and reliability, and the easiest/cheapest installation. Which one do you guys prefer? What's my best bet? I was looking into a EJ20 twin turbo Sub. or a 13B Turbo Rotary?
Thanks for the info
Brad

Guest · Post by **Guest** » Sat Oct 23, 2004 10:43 pm

I have no experience with the Subaru engine, so I'm not sure, but a turbo rotary engine pumping out 250hp won't have a long life. A friend of mine has a T2 RX-7 and his motor barely lasted 150,000Km. His had a mild street port and was running a higher than stock manifold pressure, but I think it was in the neighbourhood of 250Hp.

twiddlrmoris · Post by **twiddlrmoris** » Sun Oct 24, 2004 1:14 am

No cheap Ford 2.3s? Can get parts EASY and not hard to get hp. Cheap even for aftermarket parts. Esslingeracing.com. Look at the buggy section.

Would go with the Subaru of those two though. Looked at doing both and at others cars that had. I liked the Subaru set up better. Have a pal that races RX-7s and we looked it over. Just 2 many little things to overcome.

Any engine run hard will die though. Espe if you go turbo.

Putting a Ford in now. The result after looking at those two engines and being told about these ones. Check out vwbaja.net if you want to find guys with Ford 2.3s

73notch · Post by **73notch** » Sun Oct 24, 2004 2:31 am

keep it flat 4

rotary-z · Post by **rotary-z** » Mon Oct 25, 2004 8:41 am

a rotary will easily put down 250hp reliably, you need to make sure you do it right though. Tuning is very important with these engines. The subary will also easily put down 250, but with a subaru there is much more room for error in the tuning department. There are reliable stock-block 400hp rx7s running around, they take there time and make sure that it is tuned right and the tuning is done on a dyno. rotaries prefer 11.5:1 a/F ratios, and will not tolerate running lean or detionation.

I would say that getting 250 from either engine is easy (just turbo/ECU/injectors) but you will need to spend more time on the rotary for tuning.

73notch · Post by **73notch** » Mon Oct 25, 2004 5:43 pm

a subaru ej20t will almost make 250 stock, once you remove the power steering, AC, Cats, etc it should make 250 as a rough estimate.

JamesT · Post by **JamesT** » Mon Oct 25, 2004 8:53 pm

plus, it won't sound so much like a rock in a tin can

miller · Post by **miller** » Thu Oct 28, 2004 11:54 pm

Ok here are some opinions about both engines.

Rotary
-Tend to run hot wich means a well designed cooling system should be implemented.
-If you want it reliable dont turbo it. Keep em N/A and thell go forever.
-oil cooler is also rerequired.
-make sure their balanced and you reasearch about apex seals.
-Get some high gearing for your transmission. Ive heard of many reving to 12.000rpm.
-They tend to eat lots of gas and oil. Oh and they sound like crap. Until people realize thats the sound of 12.000rpm.
-They are nice on trannies due to their low torque and high rpm.
Subaru
-Get the ej25. The displacment will be worth it.
-The ej20t has 260-280hp stock.
-Basically a new subaru engine wont require anything being taken apart.

yllwveedub · Post by **yllwveedub** » Fri Oct 29, 2004 7:34 am

I was in the same position at the begining of the summer, trying to decide between a suby or a rotary. I ended up not choosing the rotary because they are fairly easy to blow up (one bad detination, or one bad over heat and the seals are done). I understand that with conservative tuning the detination shouldn't be an issue, but the idea still freaks me out. This left the suby as the best option since most I4 don't fit well since they are so long. As far as which suby engine to pick, I would definatly not go with the ej25, take a look at the follow link to see how well that fits. I went with a ej22-t, this seemed to be the best option for me because it was a lot cheeper than the wrx (ej20) and the bottom end is actually stronger, so if I ever want to go crazy with power the option is there. I should be at 250+hp with some basic upgrades. The decision is yours, it comes down to what you feel most comfortable going with. Good luck with it.

~Josh

http://www.vanbran.com/bug/conversion1.htm

Muffler Mike · Post by **Muffler Mike** » Fri Oct 29, 2004 8:33 am

250 hp in a buggy

thats going to be some incredible power to weight ratio.
looking to scare the stuff out of your self?

rotary-z · Post by **rotary-z** » Fri Oct 29, 2004 12:04 pm

Wow, does everyone here think that the rotary sounds like crap? I have heard this brought up time and time again, but mine sounds really nice. there is no high pitched noise at all and it has a very bassey tone. I am using a presilencer and a magnaflow muffler and it sounds sweet.

Anyways, The more familiar you get with the rotary, the less worried you will be about the thing blowing up. It is a really reliable motor when treated right. I believe the reason why most rotaries go up in smoke is because people run them out of oil! The rotary actually injects oil into the intake runners to keep the seals lubricated, this also means that it uses about 1 quart of oil every 3000 miles. My engine has not blown up and I have had it running at 270 degrees water temps (don't use a used radiator!) and it is still running fine.

I am not saying that the suby is a bad choice, but it really pays to research the rotary instead of just taking what other people have to say as facts. Check out www.rx7club.com for all the info you could ever use, and my engine swap has about 40,000 miles with NO PROBLEMS (except for that overheating problem, but that was fixed within a week).

Rotarys do not require that you cut up anything in the back of your car, no moving the firewall or modifying your apron. it fits WITHOUT modification.

Guest · Post by **Guest** » Fri Oct 29, 2004 6:13 pm

I wasn't trying to say that a rotary would be a bad choice, I was just explaining why I chose to go with the Suby rather than the rotary. Not having to cut up the car is definatly a positive, and I have heard some really good sounding rotaries. I completely agree that if you are considering a swap you should definalty research all of the possibilities. Good luck with your reading.

~Josh

Ribz · Post by **Ribz** » Fri Oct 29, 2004 6:38 pm

i hear the TT have real bad turbo lag, i dont have one so i cant tell you for sure... just what i hear

street car = rotary(or suby=)

dirt bound car = suby

again my .02 just the way id do it

saw a guy in LA run an 8sec 1/4 in a bug with the most wild port (peripheral port? bridge port? i dont remember its been a while since i was into rotarys) and dual 48s

needless to say it wasent a car that could be driven on the street

Dairdevil9 · Post by **Dairdevil9** » Fri Oct 29, 2004 7:19 pm

thanks for all the hints and info guys. my brothers got a 93 RX-7 13b tt that is his entire life, and he knows them in and out, and that is why i have always leaned towards the rotary(full time mechanic). my brother has built 5 motors from the ground up, a few for his car and a few for friends, so he knows how to work on em. well long story short i found a steal on ebay for a Rotary 13B-RE(rare japan only out of a Mazda Cosmo) Twin turbo motor with guestimated reliable hp output from 350-450 after im done with it. so i bought it. i couldnt turn down that kind of power! ill post some picks when things go further.

Ribz · Post by **Ribz** » Sat Oct 30, 2004 2:18 am

well if i knew someone with all that rotary knowledge i prob do the same

good luck man keep us posted, im a sucker for pictures