New Engine Swap Alternative

[724doorE]

Oh and who ahhh who designed that engine for Subaru.....

[RallyJon]

I applaud Subaru for choosing wisely from whom to steal engineering knowledge. I'm benefitting from the original, and the copy.

[avendlerdp]

Subey motors have been old hat in off road circles for a few years now. Super light, cheap, and readily available from Jap spec grey market engine dealers. The turbo ones get over 200 hp (4cyl) and weigh more like a bug motor. Truth is it would be a great swap into a 914. Seems a bit dumb to do all that work to a 911 when there are a lot of other ways to get P-motors to put out good power.

Alex

[A Quiet Boom]

Funny thing about 911 engines though, for all the alloy etc. they employ they actually weigh MORE than an aluminum headed V8 small block. I weighed my complete 2.0 with carbs after it came out of my car and was dumbfounded by it's over 500lb weight. I'd rather see a good bolt on aftermarket EFI setup for the 911's like they have for Ford and Chevy V8's than P-cars ruined with non-Porsche engines. Want a water pumper? how about a 928 motor, I saw it done somewhere once.

[sammyg2]

The porsche factory manual claims the 1973 2.7 liter CIS injected engine weighs 402 pounds. Why would your 2.0 weigh 100 pounds more?
a 3 liter with aluminum case is only 419 pounds acording to the factory.

a 928 engine does not compare well with a well built chevy V8. The chevy will make more power, cost far less, be much more reliable, better parts availability, and is lighter and smaller in physical dimension that the 928 engine.
The 928 is 4 inches longer than the chevy small block. It is also wider. That makes a big difference when doing an engine swap.

[jluetjen]

Hey -- keep in mind that I like Subarus for what they are -- Subarus. I like that they pursued a completely different path then most car manufacturers. The later cars (such as the WRX) are pretty cool!

But they're not 911's.

I'm not even going to get drawn into the V8 discussion...

[POVI]

Hey John ( jluetjen ) ..

Im installing my new race V8 motor this sat / sun in my 911
your local and welcome to drop by if you like .. i live outside
of Machester NH ...

Here is a pic of the new motor and my son ...

[Embs]

While I would be ashamed to put a Subaru engine in any 911, I have recently seen WRX EJ20 TWIN TURBO ENGINE in an on/off road rail buggy. Needless to say it was wicked fast and sounded awesome.

[wrx paul]

I've seen WRX sti engines for less than 10k. Since they put out about 300hp, they might be more cost effective than a 3.6 but who wants to buy a porsche without a porsche engine? So unless you dont care about the value, and want to drive it into the ground, it might be worth it.

[A Quiet Boom]

Originally posted by sammyg2
The porsche factory manual claims the 1973 2.7 liter CIS injected engine weighs 402 pounds. Why would your 2.0 weigh 100 pounds more?
a 3 liter with aluminum case is only 419 pounds acording to the factory.

a 928 engine does not compare well with a well built chevy V8. The chevy will make more power, cost far less, be much more reliable, better parts availability, and is lighter and smaller in physical dimension that the 928 engine.
The 928 is 4 inches longer than the chevy small block. It is also wider. That makes a big difference when doing an engine swap.

I'll bet those factory weights aren't a fully dressed motor. All I know is that I put my motor on a calibrated pallet scale and that's about the weight I got (it was two years agos so I don't remember exactly). Even at 400lbs a 911 motor still would seem heavy in given that it's an all alloy motor. Compared to an all aluminum Rover V8 at 318Lbs, it's a lump of a motor. As for the 928 motor, I realize it's a challenge and that the Chevy V8 is better choice from a price/performance standpoint, I just thought a Porsche V8 conversion would be interesting. As for myself I'm thinking of a twin turbo 3.0SC setup with low comp pistons from JE. I plan to use two small 4cyl turbos attached to custom headers running into a megasquirt modified CIS intake. If I don't go that route, I'll sell my current engine an put in a 3.3 turbo. I've never been a fan of cars with engines transplanted from another manufacturer with few exception, like the AC Cobra or Sunbeam Tiger. The difference of course is that the 911 engine has a certain historical value to me as well as being a race bred engine with many race features built right in that would cost a fortune to add to other motors. Just look at the cost to dry sump a Chevy V8 and you'll see what I mean.

[724doorE]

Bet if you fill up the coolant passages of a v-8 with water, they'd be a little heavier. Keep in mind, the 911 engine carries around a bunch of cooling fins that add up to some weight and that by design, the exhaust is heavier than the headers on a v-8, but you aren't weighing the complete v-8 exhaust out the back of the car either and the 911 engine dressed you were weighing its complete exhaust. The alt assembly is sureely heavier than a v-8 alt because of the fan and housing. Compare a flat six long block to a v-8 long block and the differenc is more noticable.

You could say that a 915 gearbox is heavier than a four speed, but then that is an incomplete comparison also

[A Quiet Boom]

Originally posted by 724doorE
Bet if you fill up the coolant passages of a v-8 with water, they'd be a little heavier. Keep in mind, the 911 engine carries around a bunch of cooling fins that add up to some weight and that by design, the exhaust is heavier than the headers on a v-8, but you aren't weighing the complete v-8 exhaust out the back of the car either and the 911 engine dressed you were weighing its complete exhaust. The alt assembly is sureely heavier than a v-8 alt because of the fan and housing. Compare a flat six long block to a v-8 long block and the differenc is more noticable.

You could say that a 915 gearbox is heavier than a four speed, but then that is an incomplete comparison also

Point taken! I really wasn't complaining about the weight, it's just that I was surprised by it. If I had been asked to guess the weight of a 911 engine prior to actually weighing it I would have guessed less than 350-400lbs. I definately agree on the exhaust point, my old drag car had a homemade 3" exhaust with flowmasters that weighed about 65lbs and stopped at the rear axle. I suppose the fair comparison would be to compare the engines will all support hardware i.e. oil tank for 911 and radiator etc. for a water pumper and full of fluids. I'd bet then the 911 engine would truly shine.

I don't know the weight of a 915 but they "feel" about the same as most front engine rear drive trannys I've lifted so that's a big savings over a live rear axle, even with a complete driveline comparision I'd bet the 911 wins by 100+lbs. It's certainly as light as a medium powered front drive setup if not lighter.

The thing I like most about the 911 engine/transaxle setup is how easily it can be removed from the car, by far the easiest I have ever worked on. I can do a 911 clutch in my car in under 6 hours by myself, this weekend I'm going to help a friend put a clutch in his 944 and the book lists 17 hours. The only car I've ever had that was faster for a clutch job was my drag car ('81 mustang) but I set it up to be easy so it's not a fair comparision. A stock mustang would be at least 6 hours if not more.

Back to the topic though. I always thought a Mazda rotary turbo would be a neat swap even though I'd never do it. I found a website one with adapter plates for the 915 transaxle. http://www.kennedyeng.com/vw_por.htm you have to admit the power to weight ratio of the rotary is attractive.

[724doorE]

Heck stock mustang, takes a few hours just to get that freakin crossover pipe off and a few more to get it back on! Don't even get me started on the Bassoni X-over i bought that didn't quite fit. Hey, Mustangs are about the easiest modern car there is to work on to be honest. Sometimes I wish I still had one of mine.

My swap interest really involves small British cars and v-8's

[Lothar]

I have no problem with people experimenting with American V8's in 911's. Given the horrifying cost of parts, a rebuild or a replacement motor, it's no surprise that someone would look at cheap, reliable power from a mass-produced motor like a Chevy small block.

Is an American V8 inconsistent with competition at the highest level of motorsports? Certainly not. Look at ALMS or the Rolex Series or the number of LeMans entries that use V8 power based on American V8's.

Is a 911 with a V8 still a Porsche in its purest form? No. Would I expect such a car to win awards at a Concourse? Probably not. Could it be a lot of fun at the track? Hell yes. And, if you blow it up, you can replace it for a lot less than a grenade of a 911 motor.

That said, I love my 3.0 CIS motor. There is nothing that sounds as good with headers and open pipes. It is music to the ears. I would miss that if I put a Chevy small block in my track car.

[soloracer]

I just purchased a Mazda 20B (Twin Turbo 3 rotor engine) that makes 300 hp/300 lb-ft of torque stock. I am told that with the proper fueling, boost control and engine management the stock twin turbo's are good for 500 hp. I purchased the adapter plate for my 915 transmission from Kennedy Engineering (highly recommend them by the way.) The biggest challenge with the project I believe will be the cooling (radiator, intercooler, oil cooler) I plan on weighing the engine to see what it weighs. My car is a 914 with a widbody kit and currently weighs 1400 lbs. I figure if I can keep it under 2000 lbs and get 400 hp out of it I will have one smokin' ride. Here is the car:



and here is the engine that will be going into it:



If you want to know what one sounds like I have a video with a stock one installed in a Delorean and another highly modified one on a dyno.

Delorean Video

Big Turbo 20B on Dyno

There is also a great video of a 20B in a Toyota Corolla that has amazing acceleration. The link is here:

600 HP 20B Toyota

[GraybeardsGhost]

Racing Beat, out here in Los Angeles built an Mazda RX7, 3 rotor, triple turbo 318 ci that put out 965 hp. It was custom built to run at the Bonneville Salt Flats for world speed records. Top speed at 258 mph before he went airborne and upside down.

[soloracer]

I have a video of that car and the accident. There is footage from both inside and outside of the car. Are you certain on the displacement? A 20B is a 2 litre engine and I don't know of anything larger in the rotary world. I also have pictures of methanol burning 2 rotor engine that made over 900 hp.

[GraybeardsGhost]

I'm pretty sure of the size of the rotary. I hauled his car for him to the TRW track in Ohio for a week, then spent the week at Bonneville while they ran the car. He (the owner) told me they had tweaked it to make a 3:1 hp ratio/ci, then add in the turbos and a 6 speed. He is currently working on a prototype rotory for airplanes.

[ViolentBlue]

I think subaru engines and mazda rotaries are cool powerplant choices, I'd definatly run on in a kit car, but not in a real p-car
there are far too many decent german built powerplants to consider before going with a japanese built engine.

oh ya, I was under the impression that subaru bought the design for thir flat 4 engine from volkswagen, the 6 was just an eveolution of that design.

[dreeves]

Why would it matter that it's not german-built?