rocraven

Anyone know how much a complete 20b weighs?
length? width? height?
Sorry I'm new to the rotary thing. But I'm looking for a new race engine. Only need 300-350hp 5-6000 rpm
torque must be good I need to hook it up to a chevy auto tranny in a 3000 lb rig. I now run an LS1 but I'm looking for a smaller and lighter engine. NOT for Drag Racing/Street Racing.

Evil Aviator

I guess I should ask you if you are considering a twin-turbo JC Cosmo 20B-REW, or a Mazda Motorsports non-turbo 20B Race engine?

For the 20B-REW, the length is about 21.5", not including the pulleys. The stock 20B-REW pullies are rather long, adding about 3.5" to the length. The height is going to depend on what kind of intake manifold and oil pan you put on it, but other than that the rotor housings are the same height and width as a standard 13B engine. The stock 20B-REW intake manifold is about 9.5" tall because it is vaulted off the block. I'm not sure about the weight, but the stock 20B-REW turbo assembly weighs a ton. Hopefully other forum members can fill in the gaps.

You may be better off with a built LS1. Have you seen this thread?
https://www.rx7club.com/forum/showth...hreadid=135921

Jeff20B

iTrader: (13)

The stock twin turbo assembly weighs 62 LBS. This includes both turbos, the manifold and short downpipe. Basically the cast iron parts.

I too have to agree that an LS1 might be the better choice.

rocraven

Thanks for the reply's. That thread was long but he finally said a 20b on the crate with stock turbos weighed 561 lbs !!!!!!!! unreal ! something that small weighs so much. I guess you guy's are right, my LS1 only weighs 390lbs, bolts up to a chevy tranny, everybody makes a harness and computor and the engines are only $2000.

Jeff20B

iTrader: (13)

The pallet my 20B came on was weight rated at 400LBS by the shipping company, so 561 sounds a little high. Infact, 400 sounds a little high. I'd say 300-something but they rounded it up. My stripped 20B feels like my old heavy REPU with everything on it (including 33lbs flywheel and cast iron waterpump) when using my engine crane. Yeah, real accurate I know, but it's only one more rotor housing, rotor, short piece of E shaft, and the 20B-only side plate which probably weighs a ton.

Does anyone here know how much the 80mm 20B-only intermediate housing weighs?

j9fd3s

iTrader: (3)

561lbs is high, id say its more like 350ish

mike

rotaspec

Well, a 13BT center plate weighs 26.5 lbs, so double that and add a little because the 20B one is twice the thickness and doesn't have the oil filler hole and only one injector hole. That would make the 20B plate about 60lbs.
At a rough calculation (haven't weighed my 20B, my bathroom scales won't cope , I would say between 350 and 400lbs for the block alone.
I think I read on one of the Cosmo websites that the longblock engine with accessories weighs 250kg (550lbs).

Jeff20B

iTrader: (13)

It can't be 60. The twin turbos and manifold with short downpipe weigh 62 lbs.

I remember lifting my 20B with my engine crane before and after removing all the stuff from it. It felt a lot lighter as a shortblock. Maybe a maximum of 30 extra lbs over my REPU engine?

My main concern about the weight is whether or not it'll be equalized be moving the battery to the back. A regular group size 24 weighs like 30 or so.

I'm guessing mazda's casting of the 20B-only plate is a bit lighter than 60 because it only needs two flat wear surfaces. They've got to be thick enough around the edges to allow the tension bolts to torque properly. There's also got to be enough material to hold the stationary gear. The rest should be hollow for the water jacket and oil drainage back to the pan.

Oh man, I hope it doesn't weigh 60 lbs.