Best engine for an exocet?

https://grassrootsmotorsports.com/articles/exocets-done-three-different-ways/

3.6 pentastar and the 8 speed ZF,  just to be different.

jwagner (Forum Supporter) said:

I had a K20 in mine and thought that was the right motor since I ran in a 2L class and SCCA DM.  However it cost a damn lot of money to build the motor and also for the KMiata stuff to install it.

I don't see how a LS is worthwhile in these cars.  First gear was pretty much useless even with the K20.  It was faster to start in second to limit the wheelspin and skip the 1-2 shift.  The back end is light enough that a couple of stout guys can pick it up and walk with it - can you say traction limited?  While an LS isn't a lot heavier than the Mazda 1.8, it doesn't do the F/R balance, which is already nose heavy, any favors. 

IMO the logical candidates for this car are turbocharging the Miata motor (by far the easiest and most cost effective), a K24, and maybe a K20 which will be by far the most expensive of these.  (Maybe a LFX? Hmmm...). Or just run the 1.8 with bolt ons, a megasquirt and a tune.  150WHP is a lot of fun in a 1500lb car.

I've tried this line of reasoning on my buddy. But he just sees ultimate HP numbers. He's blind to the fact that all the horsepowers in the world don't do any good if you can't get them to the ground.  

jwagner (Forum Supporter) said:

https://grassrootsmotorsports.com/articles/exocets-done-three-different-ways/

 

The sub-heading for that article should be "Is a small kart track really the best place to test a car that has less than 3.5 lbs/hp?" :)

If your world is limited to the small range of automotive dynamics that is autocrossing, you should be chasing weight instead of power. But if you get outside parking lots, there are situations where you can use power. My V8 Miata is not that much faster now than it was with a 185 hp four cylinder on our local kart track. Oh, it's faster by a couple of seconds, but it's not massive. But take it to High Plains Raceway and the difference is immense. My point is that just because you can't use all the power in a low gear doesn't mean you can't use it when things get serious, not that a supercharged 6.3L V8 is the right engine.

I'm not sure why everyone thinks the LS in a Exocet is some undriveable monster just waiting to kill you. Mine is a pretty mild build in the 340-50 ish HP at the tire. And like Keith said above yeah you can't use it all in first gear but from second gear on mine does not get super crazy. You drive it ham fisted and it can be made to slide around but in general it's just really hard acceleration in any of the higher gears and I don't seem to feel the aero wall like a stock Miata engine would. 

Now as far as other engines go I think the 4 cylinder ecoboost engine from the new Mustang would be pretty cool in a Exocet. 300+ HP with a pretty low weight. And the LFX V6 out of the Camero is pretty compelling also. Lot's of RPM range and 300+ also. The diversity of drivetrains in Exocet's is pretty wild. I think they pretty much cover the spectrum from rotary's to 5 cylinders. The platform really is a blank canvas for a owner to get creative. 

periphial ported 4 rotor.  You wanna get nuts, lets get nuts

Old iron-block turbo 2.3 Ford.

Hayabusa

Four cylinder for packaging ease and weight.

The GM Ecotecs - a mild tune and slight change to turbo spec and you are sitting c. 400 bhp without going inside the engine.  And it looks kind of like a Miata.....  Want more power? Do some inner engine improvements an the sky is the limit (they passed 600 bhp about 10 years ago and some are hitting above 800 now)   See below

A modest (570 bhp) LNF in a Cobalt on the dyno

https://www.youtube.com/watch?v=erqFMigGLPk&feature=emb_logo

LFX is the answer you're looking for. Under-stressed, very light, and is paired with a transmission (ding ding ding) that can handle it no problem.

Honda K-series being a close second for me. You have to consider transmissions with this one, but they're light and rev good. 

Though mine is a 1.6 and it's still a riot.

In reply to wspohn :

The ecotec has the problem, so far as I'm aware - of transmissions that could deal with that power in a miata bolt in swap, right? Big power BP motors are using BMW transmissions at this point if you don't simply enjoy replacing transmissions.

So having done endless amounts of research on an engine swap for my 1600lb Datsun I finally decided why a push rod V8 is the answer when you want power.  All of the turbo twin cam 4 cyl motors are pushing 400lbs, once you factor in things like the intercooler & plumbing, some are over that. So for a mere 20-40lbs more you can buy a V8 and get mega easy parts availability. Once you factor in the weight of the transmission the drive trains may way exactly the same.

With that said I still find the lightest motor capable of 120-150whp and work on making aerodynamic body work.

In reply to DrBoost :

So your "buddy" just wants to build a SEMA car with impressive numbers and look, but little to now actual use.

Gotcha.

Why not do something truly stupid then and go with Bugatti Veyron power? 

Or maybe an AMG powerplant?

Expensive, but different and hard to deny they produce impressive numbers.

In reply to accordionfolder :

A 35% weight reduction should do a lot to mitigate transmission concerns.

In reply to Driven5 :

Backed by data or hope? 6 speeds are eaten at an alarming rate at anyone doing real track work in them with power that's not even close to that. 

@Keith - Yeah, an Exocet with more power is going to be faster, but if you're running a lot of big tracks with long straights and high speed sections, maybe the Exocet isn't the right choice.  It's got the aero of a large brick (probably not even that good) and at some point the Miata you started with might be the better choice.  On a technical 2 mile track it's a monster that runs with the big dogs.  On Road America the Corvettes fly by on the long straights.  Don't know HPR but I think it's more the former?

I would stay with the basic design center of the car:  Small, light, simple.  (and fast)

Strike_Zero said:

Dusterbd13-michael (Forum Supporter) said:

I know a guy that stuffed a 60*v6 in a miata and its a riot to drive. Can't imagine using the later 3500/3900 in a lighter chassis. 

I came here to say this. The 60* V6 is compact and light. With the right parts, a 3900 is 300hp and a 3500 (short stroke 3900) ain't too far behind. The older 3400 and 3500 (big bore 3400) make some serious hp with a snail.

All these engines are strangled by the factory cam . . . If memory serves me correct, GM used the same cam specs on all these engines.

Chevy also used really restrictive exhaust manifolds, to keep them a step below the 3800.  With a decent header and '01-up heads, they can make a lot of power.

The next downside is, the cam is so high up in the block, there isn't enough room for a really high lift cam unless you use flat tappets like the engine architecture was designed around. (Roller lifters are taller, and lift is limited by the deck)  Not the end of the world, but it leaves a little on the table.

wspohn said:

Four cylinder for packaging ease and weight.

The GM Ecotecs - a mild tune and slight change to turbo spec and you are sitting c. 400 bhp without going inside the engine.  And it looks kind of like a Miata.....  Want more power? Do some inner engine improvements an the sky is the limit (they passed 600 bhp about 10 years ago and some are hitting above 800 now)   See below

 

A modest (570 bhp) LNF in a Cobalt on the dyno

 

https://www.youtube.com/watch?v=erqFMigGLPk&feature=emb_logo

 

10 years ago, give or take, GM had an Ecotec recipe book that included 1200hp turbo engines, part numbers to adapt 4T65s to them, how to wire one for manual shift, GMPP part numbers for 930 axle adaptors...

GM was trying to make a big impression on import drag racing.

pres589 (djronnebaum) said:

Street ported 13b!  brap brap brap brap brap brap

Street ports go hmmm, they don't brap

jwagner (Forum Supporter) said:

@Keith - Yeah, an Exocet with more power is going to be faster, but if you're running a lot of big tracks with long straights and high speed sections, maybe the Exocet isn't the right choice.  It's got the aero of a large brick (probably not even that good) and at some point the Miata you started with might be the better choice.  On a technical 2 mile track it's a monster that runs with the big dogs.  On Road America the Corvettes fly by on the long straights.  Don't know HPR but I think it's more the former?

I would stay with the basic design center of the car:  Small, light, simple.  (and fast)

Fair point about the aero, there's likely a crossover somewhere. I don't know where it would be, though. On the front straight of Laguna Seca, a stock 1.8-powered Exocet will basically hold station with the Spec Miatas - but it's got more braking, acceleration and cornering performance. So if we extrapolate that into the megapower sphere, how fast do you have to go before the aero of the Exocet punishes it enough that it can't punch through the air fast enough to keep up with a Miata with the same power? I suspect it's a fairly high speed range, more Big Willow or Spa.

I still like the turbo Miata powerplant for the power/weight and ease of build. It'll get you on the road sooner than any other option and they're all most fun when they're self-propelled.

Keith Tanner said:

and they're all most fun when they're self-propelled.

Now that's fact. 

In reply to accordionfolder :

Who said the car for this exercise was going to be used for the kind of track work that eats NB 6spd's at an alarming rate with not even close to 250whp?

In reply to Driven5 :

Offenhauser or a little more modern Meyer Drake. 

In reply to Driven5 :

Why bother with the ecotec if your aim is <300? Over 300 and you're on borrowed time for a 6speed Exocet or not.

Came to say lfx. Good noises (like Maranello good) , relatively light weight, short length (to keep weight rearward), stout, under stressed driveline, readily available at reasonable cost, swap parts availability.