Hi all,
I know this is kind of an odd question, but after trying to figure this out from various other sources, I figured I'd try the wealth of knowledge at AR15.com.

Ok, I recently purchased a basket-case Lotus Esprit.  It's actually a nice car mechanically, but needs paint and interior.

The car comes with a hopped-up 2.2L 4cyl engine which produces 205hp.

Thing is, I'd like to get up around 250-275hp and the 2.2L is aready a stressed engine (as is natural in sports cars).
Now, I could probably manage the ponies out of the motor, but rebuilds on these things cost astronomical amounts of cash (8 grand-ish).

So, what I'd like to do is to prepare an alternate motor that I could use.  I've done engine conversions before and am familiar with making adapter plates/linkages...etc, but it is the motor itself that I'm having trouble determining.

A Lotus is very much about handling, and the weight is a primary concern. The original 4cyl is completely aluminum and so even if I go with more cylinders, I need to keep an aluminum block in there.
V8's will (barely) fit, but are heavier, and over-powered for the car which could lead to a very expensive pre-mature tranny failure.

Ok, so basically I'm looking for an aluminum block V6 which can be made to produce 250-300hp. Supercharged is ok, but it cannot be a transversely mounted style motor as you would see in the pontiacs 3.8 and similar (unless these don't mind being mounted the "normal" way.

So... super light AL high-reving V6 (preferably American) engine which produces the required HP's. (HP is more important than torque in this case because of the car's design).
How do I obtain this, and if I were looking for a used motor, which cars would they be in?

Many Many Thanks
SameShot

No V6 gearheads here?

BTT

  I believe some of the Buick regals used turbocharged v-6's in the mid '80s. They were corvette killers, so GM dropped them. May have been aluminum, if I recall... fullclip

I don't know about a V6, but my brother had a Buick aluminum-block V8 in the back of a '71 VW bus. Damn thing hauled ass. I heard a lot of guys use them for small cars because they are small and lightweight.

It has already be designed to max by great engineers,what more can you add?  The weight body ratio has been computed and built,why not go with what you have?

 Even rebuilt the car and motor will get you max usage and money back if you decide to pass it on or to sell it!   The Mazta RX had a really hot Rotary maybe that would get you the 350 chevy outgunned little engine you need!

 Bob  Its your toy,have fun!    [:D]

Transverse engines don't care which way the crank points so look at other factors.  How about an Olds Aoura V8 or the Caddy equivalent - maybe Infinity if you are into rice?

Not sure of any American V6 in aluminum.

The northstar caddy  V8 engine put out 275-300 stock.Depending on version.Its all aluminum but only comes front wheel drive.However the 60 degree V6 2.8 [mostly S-10] trans will fit with a few mods.I believe there are other kits for diffrent trans out now.The big obsticle is the engine width.more than a small block chevy I believe.

On a horsepower-per-pound basis, it's hard to beat the Nissan VQ series of V6s. The current-generation 3.5L version is good for at least 260 HP (normally aspirated) in the passenger cars — or quite a bit more in the new Z-car.

For power on a budget, you might consider acquiring the earlier 3.0L version out of a '96-or-newer wrecked Maxima — Same great internals, in a slightly smaller package.

If I remember correctly, the Lotus engines were turbocharged right ?

If so, all I'd do is crank up the boost on the turbo...

Turbos are surprisingly gentle to engines, compared to superchargers, and nitrous...

I actually think I read somewhere that those little Lotus motors were capable of over 300hp with a decent turbo...

Try contacting a company called "Turbonetics"
They've got some serious stuff...

Thanks for the replies fellas....

'Thing is, I really *don't* want to worry about 8 grand rebuilds.
My car is a '77...the turbo's didn't debute until '80, and it is correct that you can go well over 300 (even over 400) on those motors.
I plan to save my original motor for resale value, and it only has about 4k mi on it.
There are other things about the Lotus motor that are quite annoying tho.... it uses "shims" to adjust the valves and the whole head has to come off just to replace a shim with a different sized on (oh man)... the belts are very hard to get to...the list goes on.  I'd much rather get into a 5 thousand dollar motor that cost 2 grand to rebuild than a 15 thousand dollar motor which costs 8 grand to rebuild, and honestly, GM surely makes a *better* motor, although not as "exotic".
To reach 205hp, the Lotus motor is cammed out, timed out, flowed out, and probably stressed out.
The V6's should be relatively relaxed at about 250hp.

The GM (Buick) engine mentioned below is a great candidate, but the problem I am having is figuring out which blocks (if any) are aluminum. You can get them in supercharged flavors which meet my HP requirement dead-on.

I plan to make this conversion reversable, but basically the car was cheap enough for me to buy and fix up, but the first thrown rod and it would be out of my range to fix.

As I mentioned before, I am familiar with V8 conversions, but they are just not well suited to this car. Too much torque, too tight, and too heavy.
Also, I realize there are some really great import engines out there which would fill the bill (I own a 300ZX twin turbo), but I really want to stick with an American motor for the conversion.

I'm suprised that it seems that AL block V6's are so hard to locate. They must be out there in some relatively common performance sedan?

Thanks!
SameShot

You should look into the all-aluminum Alfa Romeo V6 engine.

The stock 3.0V6 motors put out 182hp from the factory.  However, as they have been around, Alfa Romeo racers have hopped up these motors to reliably put out 200-220hp depending on how much coin you want to spend.

They're VERY reliable and the bottom end has been known to reliably handle 400hp (with twin turbos).

They're light, too.  Built entirely out of aluminum - with the exception of the steel wet liners - they're less than 400lb complete with accessories (alternator, power steering pump, water pump, A/C compressor).

E-mail me off-board ... I can help you locate and customize this motor.