Rotary vs Turbo VS Nos

MzQ · Post by **MzQ** » Sat Dec 01, 2001 4:45 pm

One of the reasons the rotaries were killed and they almost died in the seventies is because they could not meet mpg requirements... With the 2nd gen RX-7 they found out after making prototypes that it wouldn't make it either... That's why if you look real hard at a '86 & up you'll notice more aluminum that steel...

Funny story... Mazda disassebled the whole car piece by piece. Laid out every part in a warehouse and had employees come in and see where they could save weight...

And they never made they EPA ratings... You'd never see 22mpg even in a new one...

danielmcaulay · Post by **danielmcaulay** » Sun Dec 16, 2001 3:20 pm

Does any one out the know what is better for a daily driver 69 beatle.im looking at 3 possibilities
1.and 12a conversion which will be around $2000

2.The budget turbo kit $1895 + install time

3.Nos $700 But not perment power.

Any info on the pros and cons of any of the above would be great

O2_cooled · Post by **O2_cooled** » Sun Dec 16, 2001 4:07 pm

What makes you think the rotary conversion will cost 2,000$?
Look into junkyard engines rather than "rebuilt" engines.

spootman · Post by **spootman** » Sun Dec 16, 2001 4:28 pm

yeah and the turbo kit will cost more, you will want to work your heads and get a c/w crank to get the most out of it, and maybe up your displacement.
I've been thinking about the rotary conversion for a long time. I am most worried about the tranny. But, I figure just have a spare tranny ready...

MzQ · Post by **MzQ** » Sun Dec 16, 2001 5:13 pm

Sorry to disappoint,,, but Rotaries don't have heads. And there's NO way to raise your displacement, unless you import a three rotor engine from Japan... There's also no cam or even valves. There very similar to two stroke engines... That does make them easier to work on...

There also very critical of air/fuel mixture... Turbos make huge power, but so will an extended port 12A... In the area of 160hp... A full extend port will make the drivabilty worst but'll get you near 200hp without turbo or nitrous and without the dangers of killing the engine from poor tuning...

[This message has been edited by MzQ (edited 12-16-2001).]

Kenghia · Post by **Kenghia** » Sun Dec 16, 2001 8:58 pm

Many moons ago I bought a rotary street port short block ($1,800) for my 79 RX-7. Horsepower was rated at 225. This as a street motor back then was ridiculous, gobs of power, reliable and drivable.

It was driven daily. Victems where mustangs, grand national, 911, and Mr-2. Played with a ferrari on the hiway but he didn't do anything must have been laughing at me. Well i tried and was ready had it in 3rd gear doing 70mph.

I'm telling you these engines when built right and maintained are bullet proof and very fun to drive. My Karmann Ghia will have one, a 13b turbo that a good friend will build, when I get around to it and of course when the funds become available. My ghia is stripped to bare metal so no time soon.

If anyone wants an engine builder let me know. I have a very good friend whos blood flows with rotary.

calereeves · Post by **calereeves** » Mon Dec 17, 2001 10:02 am

I should be getting my 13b this week for a whopping 300 dollars

I need to find someone that can do the port work.
Kenghia, where is this guy that breaths rotaries? I live in texas, and I need someone to do a bridge port for me... I cant decide though...is the lack of driving comfort with the bridg worth the power???? I am thinking so right now, but has anyone here ever used a bridge ported engine? I WILL have a turbo in short order, and the engine will be carbed, so scratch the efi...BUT, will the carbed up, bridge ported engine be so completely undrivable that I'd rather have a little old stock VW engine? I'm getting the engine no matter what (the 13b) but I just havent decided yet what to do, other than the carb and the turbo.

I think that with all the room left over in the bug engine compartment, I MIGHT have enough room for a small intercooler...what are your thoughts there? Mount about a 8"x12" intercooler flat with an elctric fan blowing air down to the road?

Thanks,
Cale Reeves

MSN Messenger: [email protected]

Kenghia · Post by **Kenghia** » Mon Dec 17, 2001 12:00 pm

Cal i sent you info at your MSN email

spootman · Post by **spootman** » Mon Dec 17, 2001 1:03 pm

MzQ,You misunderstood me. I meant up the displacement and change the heads on the VW engine, the one that he was thinking of putting the turbo kit on. It seems like if you were spending all that money on the turbo it would be more HP per dollar if you made some engine mods too.
I do have some rotary experience, I used to have a snowmobile with one.

By the way, you guys who are planning on rotary power, what are you gonna do for a trans?

[This message has been edited by spootman (edited 12-17-2001).]

MzQ · Post by **MzQ** » Mon Dec 17, 2001 4:41 pm

Sorry I Did misunderstand...

Calreeves,
Bridge porting isn't a good street modifaction... The divability is way off and the power will be very high in rpms... A extended street port is the best compromise...

If you've got a 6 port engine the secondary ports are already hugh, and with a carburator these no way of controlling them... Also there's not much room between the intake ports, primary and secondary, and the water jacket... If the porting's too radical you leak water, if it's not you'll not get much power gain... I had to sacrafice a center and end housing to find just how much I could go, and when I had a freeze I still lost my engine... If you where lucky enough to find a "earley" 4port 13B this all goes out the window... The turbo motors ar totaly different than the 6port, they use 4ports, but are still limiting is their port sizes...

The intercooler would be fine. Any is better than none...

And I don't think anything but a Bus trans will hold up... the second and third generation Rx-7s used a "factory modified" truck engine to try and hold the power... I broke mine and seen many more broke...

danielmcaulay · Post by **danielmcaulay** » Mon Dec 17, 2001 5:26 pm

OK. If i went with a rotary doing minimal work my self how much would i be looking be for i was driving down the street ,and how long does this conversion take.

O2_cooled · Post by **O2_cooled** » Mon Dec 17, 2001 10:16 pm

If you plan on having someone else do this for you it will cost A LOT surely. . How much seems nearly impossible to put an acurate estimate on. As far as time that will also very depending on how much money you are spending/how much time you have (if doing it yourself).
My personal plan for trans. is to purchase one that has been built up. I've heard too many stories of breaking them and it's probably worth to do it right the first time.

spootman · Post by **spootman** » Tue Dec 18, 2001 6:48 pm

Yeah if it wasn't for the trans problem I would have done a rotary conversion. It's just the sheer rpms that is has to handle. I always think, just use a stocker and have a spare. But then I disagree with myself and say its better to do it right...

Who wants to pull a tranny just after doing a conversion?

calereeves · Post by **calereeves** » Wed Dec 19, 2001 11:56 pm

For the tranny I plan on running my porsche 914 trans, so no worries about not holding the power.

About the 6 port engines though, when you do the carb conversion, do the secondaries stay open the whole time? If so, would that mean I get gallons per mile instead of mpg?

Thanks,
Cale

CORRECT MSN Messenger == [email protected]

calereeves · Post by **calereeves** » Thu Dec 20, 2001 8:11 am

Oh yeah, MzQ, what kind of gains would I get on the six port by doing the minimal port extension that the 6 port will allow?
Cale