I'm thinking ahead on a project. Target is the lightest engine that meets these specs. Must be rwd or convertible to rwd. Target hp is 125 NA and 200 forced induction. Must be cheap as it will be for a Challenge build.
What I've come up with so far is the Suzuki G13 and maybe the Saturn LLO as I read the T5 can be adapted maybe? Any out there I'm missing?
How light?
Miata and Cummins... (not light anymore!)
rotary checks all these boxes.
In reply to Ovid_and_Flem:
I'd like less than 400ish lbs engine and trans but the lighter the better.
In reply to NordicSaab:
I can't find them cheap nor ready available. Even though it isn't a listed factor the reliability of spinning Doritos scares me.
Stampie wrote: In reply to Ovid_and_Flem: I'd like less than 400ish lbs engine and trans but the lighter the better. In reply to NordicSaab: I can't find them cheap nor ready available. Even though it isn't a listed factor the reliability of spinning Doritos scares me.
The M10 out of the '02 fits the bill. I also have x2 transmissions for it. There are also many well documented turbo/FI conversions for well over 200HP. Not to mention I know where one is available :)
Stampie wrote: I can't find them cheap nor ready available. Even though it isn't a listed factor the reliability of spinning Doritos scares me.
I will allow that anybody who calls it "spinning doritos" is going to be unfamiliar with them. This isn't a dig, it's an observation.
Rotaries are the definition of reliability. You're never going to throw a rod, or float the valves to result in spitting out a shim or popping a valve head off the stem or breaking the timing chain as a result, or any of the hundreds of other horrible ways piston engines die. They just work until they are worn out, and there are simple ways to minimize wear.
But they aren't as light as many modern 4-cylinders and they certainly aren't as cheap. Shop around and you can pick up a Duratec four for peanuts, and it's been in two RWD chassis already (Miata, Ranger) so RWD transmissions are certainly available. They will meet your "turbo" power goal without a turbo, and they weigh very little. Certainly less than a lessor engine like a Saturn or Suzuki four with turbo paraphernalia added.
Knurled wrote:Stampie wrote: I can't find them cheap nor ready available. Even though it isn't a listed factor the reliability of spinning Doritos scares me.I will allow that anybody who calls it "spinning doritos" is going to be unfamiliar with them. This isn't a dig, it's an observation. Rotaries are the definition of reliability. You're never going to throw a rod, or float the valves to result in spitting out a shim or popping a valve head off the stem or breaking the timing chain as a result, or any of the hundreds of other horrible ways piston engines die. They just work until they are worn out, and there are simple ways to minimize wear. But they aren't as light as many modern 4-cylinders and they certainly aren't as cheap. Shop around and you can pick up a Duratec four for peanuts, and it's been in two RWD chassis already (Miata, Ranger) so RWD transmissions are certainly available. They will meet your "turbo" power goal without a turbo, and they weigh very little. Certainly less than a lessor engine like a Saturn or Suzuki four with turbo paraphernalia added.
I've had some seriously powerful engines and never suffered any of those issues. I've also never had apex seals wear out at 30K.
Not bashing, but the most reliable rotaries are NA, and they only have two torques per rotor. And are harder to find every day. And are not cheap. Personally, I'be not known a rotary owner that didn't either switch to a piston engine, or drop an LSx in place of the spinning triangles.
Best bet is an aluminum 5.3 Chevy v8. By the time you add on a turbo setup or supercharger you will be at the same weight.
Unless you get a k20 Honda motor and turn it sideways. Should be able to find a wrecked RSX or old civic SI to pull the engine from and recoup 100%.
400lbs, engine, transmission and boost is an extreme goal on a budget.
DrBoost wrote: I've had some seriously powerful engines and never suffered any of those issues. I've also never had apex seals wear out at 30K. Not bashing, but the most reliable rotaries are NA, and they only have two torques per rotor.
Nothing fancy in the engine, the most expensive parts involve having good drivability (EFI, not carb) and keeping it quiet enough to drive on the street.
Of course, he's looking for 125hp N/A, not 270hp. (I have half a mind to get rid of the over-9000 fuel dump so the power curve keeps going, just to see what kind of numbers it makes at 10k)
How about motorcycle power?
GSXR 1000 should give you 225 hp NA, 300 turboed. Not much torque at the bottom end, but 12,000 RPM should make up for it in fun factor.
Driveshaft conversion kits are available.
Engine and transmission combined are about 125 lbs.
If you can keep the total car weight low enough....
+1 for the more modern larger displacement 4 cylinder from a ranger. Or do the ranger trans with the 2.5. Then if you want to throw a turbo on it shoot for 300hp instead of 200.
In reply to SVreX:
I like your thinking.
If it makes horsepower, then it makes the torque. That is what gearing is for.
Besides, if this is going into something with a solid axle, for handling reasons you want the shortest rear gear you can stomach. The higher numerically the gear ratio, the less the driveshaft is trying to lift the right side tire, and the more even the handling is going to be.
Knurled wrote: Besides, if this is going into something with a solid axle, for handling reasons you want the shortest rear gear you can stomach. The higher numerically the gear ratio, the less the driveshaft is trying to lift the right side tire, and the more even the handling is going to be.
WHAT?! Is this a thing? Is this real life? Not trying to hijack but i want to hear more about this.
Bikes engine setups are weird-IIRC there is a reduction before the transmission that makes the driveshaft output speeds more car like. I think motoiq detailed that somewhere. 
edit: here tis
In reply to Opti:
It's simple math, really... for the same amount of forward acceleration (force pushing the car down on the rearend) there will be less torque on the driveshaft trying to rotate the rearend like a propeller.
If you have a 3 link suspension, there are things you can do with the third link to oppose driveshaft torque (angle the link so tension on it tries to lift the left side in compensation) but then you make the braking uneven. Not sure it's possible to do this with a torque arm and it's possible with a 4 link but much more fiddly.
This is one of the ways in which I'll allow independent suspension does it better than solid axle. I personally don't think it is enough to make up for IRS's other shortcomings, but the cool thing about the world is we don't all have to drive the same car 
Besides, it's a perfectly cromulent excuse to run rearend gears that start with a 5.
On the rotaries you're right, I just don't have the experience with them. Love the idea but not for this project as the expense is too high.
Not going to do an LS. Aluminum or not it's still close to 500 lbs engine only so no.
The M10 ... actually peaked my interest but about 100 lbs too much and I'm looking for a donor car to zero out as much cost as possible.
So far the Saturn LLO T5 combo at 300ish lbs together is the winner in my mind for car engines. They're all over the place just don't know if the combo works or if it is an internet myth.
And then the motorcycle engines ... Yes I like the idea. Going to research more.
If you like that Busa Miata (read it a few years back) you'll love this Busa MG. I've seen the MG in person and was hard not to sell my first born to buy it.
I would be looking at Honda Civic Si FWD engine, trans, LSD all packaged together with the suspension and subframe. Move it around the back of a hatchback and cut until it fits. Lock the tie rods in place. Run a cable shifter and hydraulic clutch. Turn the header out the back. Gut whatever was under the hood before and replace with fuel cell and water and oil cooler plumbing. Done.
An original Fiesta or other lightweight 80s hatchback would be perfect for this. Anything that does not already have an engine in that location, actually... VW pickup? Sure. Yugo, absolutely. Chevette? Oh yeah. :)
In reply to Knurled:
I was about to call bull on this, until I read what you said again and realized it actually makes sense.
Guess I need to find a 5.13 gear set for both of my diffs and build a screamer motor to make up for the new found need for 8k rpm.
An MG Midget is 1620 lbs with the factory A-series in the car. A 1275 weighs around 250lbs (IIRC), and the trans weighs 40 lbs. So a roller is basically 1330 lbs or so. Squids have been dropping and laying down YZF-R6s since 1999, so finding a mildly crashed 06 or 07 one really won't be hard. An R6 engine and trans weigh about 120 lbs. That would give you a RWD car that has between 131 and 125 HP NA and weighs 1450 lbs or so.
Finding bike parts/motors on craigslist is also odd. The newer parts are easier and cheaper to find because there are more of those being wrecked right now. The old stuff has been sitting a long time and often gained value in the sellers mind.
I can't tell if Andy is having a laugh, or if he's being serious. But here's a passive-aggressive post in response. 
I vote G13b, because anyone that says it will weigh as much as an aluminum LS after turbo and associated paraphernalia is absolutely, categorically incorrect.
And, for what it's worth, I went out to the garage with the bathroom scale and weighed a G13b. You know, for science!
Burrito on scale + boots and 3 beers = 181 lbs.
Burrito on scale with G13b + boots and 3 beers = 353 lbs.
Photo taken while I was out there for the sake of Internets.
So, that's 172 lbs, with alternator, flywheel, intake manifold, and oil in the sump. Essentially fully dressed minus exhaust manifold.
It looks like a fully dressed aluminum LS is between 457 and 497 lbs dry depending on whether it's wearing a flex plate or a flywheel (according to the General hisself).
If your turbo setup weighs in at 285 lbs, I suggest using something other than schedule 80 cast iron pipe for your boost tubes.
how about an Alfa 4? those were all alumimum. I might also vote for the Ford V4 that is the little sister to the Cologne V6. The Saab guys have Turboed them and back
In reply to Knurled:
This reminds me of a theory i read about swappong to a bigger rear. Example fbodies have tiny rears, people swap to a 9 inch or 12 bolt and go faster and someone theorized the cars being faster isnt just a product of increased traction from launching harder since they worry less about blowing E36 M3 up an and in part due to the added leverage on the axles since tbe ring gear is further away from the axle center.
They said the same thing, its simple math. The consensus from the major drag racers was it wasnt simple math because there were too many other variable left out of the equation.
Im not disputing you, your arguement seems very simple. Ive just never heard that before. Is it a common thing or is it something only hardcore autoxs actually deal with?
Edit. Ill try to contribute. Quad 4s weigh right over 300lbs fully dressed and make close to 200hp. Dont know how you make them rwd, but i bet its on the old interwebs.
What about the prius engine. Someone on here was talking about how cheap they are and can be pretty fun in a light car. I bet they are light, dont know about rwd.
Though I'm biased I vote that a FWD drivetrain moved to behind the seats is the most straightforward way to get what you want. Anything up to a Honda K24 can be had at very near 400 lbs and 200 hp stock (for the TSX variant). You can go MUCH higher with a turbo but that costs a lot to do it right.
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