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Index > @ the Pickup Bed (General Topics) > Thread: 20b conversion
Thread: 20b conversion
goldraven


Newbie
Posts: 5
posted July 08, 2003 08:52 PM

20b conversion

hey guys, im sorry to ask you about this, but i figure you guys might have some insight on which sites to go to regarding my questions.

I am going to be trying to put a 20b-TT engine in a VW bug, i was wondering if you guys know of any forum/website where someone has done that and what it takes. if there are any set by step instructions on how to do that on the internet... or if it has even been done yet. all your insight is greatly appreciated. thanks again guys.

Nick

       
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brad


Rotorhead
Posts: 1672
posted July 08, 2003 09:19 PM
Edited By: brad on 8 Jul 2003 21:19

The 20B forum can be found here:
http://www.rx7club.com/forum/forumdisplay.php?s=&forumid=95

It's your best bet.
____________
-brad-
74 REPU Lawn Green
81 Rx-7 racecar. 12a J-
Bridge

       
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Draggin_2600i


Redlining
Posts: 235
posted July 08, 2003 09:50 PM

Jesus.. that is insane.. You are gonna make that shit disintegrate.. But man.. What a sight that would be.. You could also try nopistons.com

Be ready to spend some $$$$

       
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rotormunky


Redlining
Orlando, Florida
Posts: 424
posted July 08, 2003 10:39 PM

quote:

I am going to be trying to put a 20b-TT engine in a VW


You're psycho.

But I LIKE it :)

Where are you located?

You can expect to spend in excess of $10,000. If that doesn't deter you then more power to you.

There are no 'kits' or instructions on stuffing that monster into a bug so you'll be breaking all new ground here, which means you'll be rebuilding the entire rear of the car.

We have a member with a 13b in a bug I think don't we? The flywheel/clutch assembly on the 20b ought to bolt to the transaxle they use for the 13b but honestly I don't know if that transaxle will hold up to the power (and why would anyone go to the expense of a 20bTT unless they plan on pushing 600+ HP and close to 500 pound/feet of toque).

Most likely you'll shatter (and I mean spray shrapnel for a hundred feet) the transaxle. Plus I don't know if you'll be able to rig any sort of traction with that much torque.

Have you already got the 20b? Because if you don't yet my advice is to build a 13bt to about 350hp and 275pound/feet of torque, put wheelie bars on it and enjoy running in the 9s.

If you gained more than .5 seconds with the 20b (traction and reliability issues) I'd be surprised.

If you've just got a tonne of money and time and this is some sort of sick obsession I say go for it! And if you're anywhere near Florida I'll help you however I can.

Good luck with it in any event.


____________
-Martin
Orlando, Florida

http://www.themonkeyhouse.org/REPU

'77 REPU (Some assembly required :)
'91 Cabrio (Battered and bruised, but she's still my baby.)

        Click here to visit rotormunky's homepage. 
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Klaus43


Rotorhead
Posts: 1259
posted July 09, 2003 11:07 AM

I think the VW bus transaxle

could possibly be built to handle the power... but I question whether the pan --or any of the rest of the car-- is suited to... keeping the nose on the ground could be a major problem! Then there's the design and construction of an extremely radical exhaust system, nevermind plumbing cooling... and how much motor is sticking how far out the ass end...
That's not to say I'm not intrigued by your concept... after all, I dream about building a motorcycle around a mazda rotary from time to time!

       
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goldraven


Newbie
Posts: 5
posted July 09, 2003 11:30 AM

heheh, im glad you guys support me =). i live in fort collins colorado. if any of you are near there. and there will be money behind this project, dont worry. i just gotta figure out wtf im going to be doing. looks like it will be a shot in the dark. but i'll keep you guys posted on the progress of it.

Nick

       
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Jeff20B


Moderator
Posts: 661
posted July 09, 2003 12:33 PM
Edited By: Jeff20B on 9 Jul 2003 12:35

I once lived in Fort Collins. Anyway, here is a website specifically about VW engine swaps.

http://frost.bbboy.net/vwengineconversions

20B-TT=bad. 20BREW with a single large turbo is better.

Personally, I'd ditch the stock twins, unless you want to be limited to around 300HP or thereabouts. They're also very heavy and require the use of the stock unusual dual thermostat waterpump which is also big and heavy. You'd also need to wire the flapper door open, unless you could somehow use the stock ECU which is a nightmare to hook up.

Also, yes, a 5 rib bus trans is a good one to use, but then again, it's probably not going to be enough for a 20B. A Porche tranny might work better.

I'd like to do a streetported 12A in a bug. Less low end torque, so the stock tranny will live for a while, and the high end power can build up nice and smoothly with a wider RPM range for a higher top speed. Plus the weight is similar (it's like 40LBS extra, which isn't too bad for like 100 extra HP over stock).

Not trying to discourage you. I'm just tossing out my opinions and prejudices. :)
____________
'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7

       
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goldraven


Newbie
Posts: 5
posted July 09, 2003 06:30 PM

any opinions are helpful. that website is fantastic. I am learning what you are saying about the 20b-TT and the added weight problem. i think i am going to take your advise with this one and use the 20brew. thanks man.

       
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Jeff20B


Moderator
Posts: 661
posted July 09, 2003 08:19 PM

Just to let you know, I was actually cracking a joke above. There is no such thing as a 20B-TT. Its proper name is the 20BREW. REW means rotary engine double turbo. The W sounds like the word "double" coming from someone with a japanese accent.

So now you know. :)

Hey, go ahead and start a new thread over there and I can give you some advice about the 20B. I have one, and have been into them since '97, so I can pass on some info, if you're interested. Others will be able to read about your progress and help out too.
____________
'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7

       
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goldraven


Newbie
Posts: 5
posted July 10, 2003 11:06 AM

AHHH, i've been reading for like 2 days on this shit. and TT and REW = the same thing? im going to pull my hair out. cause there are slight references throughout every page with rotary info. i feel like such a boob right now.

       
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goldraven


Newbie
Posts: 5
posted July 10, 2003 11:11 AM

as you can already tell, i am approaching this project with total ignorance. Can you direct me to a page that lists each type of rotary engine, from the 10a's to the 20b's. explaining exactly what it is. I feel like i am still cloudy as to which engine people are talking about in the forums. 13bt, 13b-REW, blah blah blah. thanks man.

       
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rotormunky


Redlining
Orlando, Florida
Posts: 424
posted July 10, 2003 11:24 AM

If you see 20bTT its just someone using shorthand to mean "Twin-Turbo", its not an engine designation.

In all likelyhood you'll wind up with a 20brew but if you can swing it and it drops money off the price try to buy one without all the turbo aparatus on it.

You'll want to go single turbo for the big power gains, plus it'll be easier to manage. You realise you're going to have to blow several grand on turbos, exhaust and some sort of ECU right? That's not counting the engine or anything else.

I know you said money is not an issue, just be sure that $15k+ is not an issue.

I'm thinking you're going to pay a couple grand for the engine. I'd want to rebuild it but could see shy you might not want to. You'll need a custome manifold and exhaust, the turbo setup itself intercooler, cooling system plumbing...

All said and done I don't think I could do it for less than $20,000.

That sound about right to anyone else? Considering you have to basically build a subframe for the rear of hte car. Plus I'm thinking you'll have to put half the ening in the back seat.

I just can't see that tranzaxle standing up to 300-500 poundfeet of torque.


____________
-Martin
Orlando, Florida

http://www.themonkeyhouse.org/REPU

'77 REPU (Some assembly required :)
'91 Cabrio (Battered and bruised, but she's still my baby.)

        Click here to visit rotormunky's homepage. 
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Jeff20B


Moderator
Posts: 661
posted July 10, 2003 12:30 PM

The 13BRE out of a JC Cosmo is actually a 13BREW, even though it is a different engine than what came out of a 3rd gen (or FD as we like to call them). It has 13BRE casted into the upper intake manifold. The 20B has 3ROTOR casted into its UIM. That's way too much to type. Anything you can do to type less is ok by me, so when people say 12AT and 13BT, it is sort of ok, but when they say 13BTT and 20BTT or any variation, it's all wrong. :)

To keep it simple, because we're all kinda stupid, (you know, the KISS acronym?), If it came out of a JC Cosmo, it's either a 13BRE, or a 20B. There were no other engines available in that car. If it came out of an FD, it's a 13BREW. Again, no other engines available. If it came out of a 2nd gen or FC, which is quicker to type, it's either S4 or S5 turbo or NA, 13B only (there is a difference from series 4 to series 5 turbo and NA engines). If it came out of some rare Mazda cars in the early '80s, has a turbo, and it's a 12A, it's ok to call it a 12A turbo, or 12AT.

I guess I'm only bringing this up because it just makes it easier for everyone if we all know which engine we're talking about. And for a crash course in engine differences and other cool rotary info, here's Craig's Rotary Page: http://cp_www.tripod.com/rotary/index.htm or http://cpwww.topcities.com/rotary/index.htm. Both might be down at the moment, but at least one should come back online soon.
____________
'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7

       
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Klaus43


Rotorhead
Posts: 1259
posted July 11, 2003 06:06 PM

While you're at it,

you'll want to make that bug a bit more aerodynamic, since you'll be approaching supersonic speeds in seconds! You are intending to drag race this puppy, aren't you? Might as well go for the full-tube-frame approach, drop that lightened, modified beetle replica shell over the top... remember to leave appropriate spaces in the air dam for the massive oil coolers!

       
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