lightest route to 400HP

Let's say your looking to do an engine swap. What is the lightest route to a legitimate 400 HP? Something with a broad torque range, rear wheel drive application, and a robust manual transmission. Consider the weight of the tranny as well, and since this is GRM, lets keep cost in mind. There has to be something better than an LS1/T56 swap, but that seems like a good place to start.

Any aversion to a turbo?

Turbos are good. My current project is a 4.0 Rover V8 with a turbo and megasquirt. Should be close to 400 HP, but I'm looking for something easier for another project I'm thinking about.

Although I would like to say the Ford 5.0 in all reality the best choice would be a SR20DET IMHO

sr20det

not a fan of the sr20. too sensitive to tuning. id prefer a ca18det over it truthfully. piston skirts are too short and top ring too close to the piston face for my likes on the sr20. vg30 sohc could do it cheaply. a turbo vortec 350 could do it easily. and a 3.8 gm v6 could do it,. ls1/t56 combo tho is prob the cheapest youll find.... saw it on cl a few days ago a ls1 t56 and wireing harness and ecm for 1200.

LM7 plus a cam and headers

KATYB wrote: saw it on cl a few days ago a ls1 t56 and wireing harness and ecm for 1200.

I can't find a t56 alone for that price.

Honda S2000 motor + turbo.

Turbo rotary is still the most for the lightest.

I thought the rotaries were actually quite heavy. Or is this just some LS1 rx7 swap propaganda?

mguar wrote: In reply to tr8todd: Horsepower sells and torque wins races.. What does that mean? 400hp and 250ft.pds of torque is just braggin' rights, 400 hp and 600 ft. pds of torque is serious.. In addition you should mention something about operating range.. 400hp over 300 rpm range is pretty worthless unless you have a 12 speed gearbox.. 400 hp over 1500 and you can start to use production transmissions..

That explains why civics with 160 ft lbs of torque can run low 12s!

mguar wrote: In reply to tr8todd: Horsepower sells and torque wins races.. What does that mean? 400hp and 250ft.pds of torque is just braggin' rights, 400 hp and 600 ft. pds of torque is serious..

That's not really entirely true anymore, and is largely just an excuse to brag used by owners of big block pushrod truck motors. (Within reason, of course)

Your example simply shows two motors that make their power in different places. Fast is fast, and i don't care HOW it does it.

An ideal engine should produce 325 plus ft.pds of torque from just below 3k all the way to 6K. A 9K rpm Honda engine is definitely not what I'm looking for. Looking for overall drivability with lots of power and lightweight. I am helping a buddy of mine build an MGA. The floor and frame rails are rusted away but the exterior sheet metal is somewhat intact. I will have to fabricate a new center frame section and floor pan, so my driveline options are open right now. His original plan was to just drop a 5.0 Ford in there, but finding a decent drop in and go is proving to be a little difficult. I'm ready to explore some new more powerful lighter options. Want to get away from Rover V8s on this project, but I keep coming back to them. Problem is that it's getting harder to find some of the rarer pieces needed for a swap. Engines are easy. Bell housings, good trannys, timing covers, etc. are tough. Making anything over 250 HP gets expensive quick.

Subaru EJ25 or EZ30/36 with a stout turbo should get you there.

Bellhousings would be the issue but definitely light weight. and cost effective.

I would think the LS1 / T56 combo is going to be hard to beat for lightness while having torque and durability. Turbos can do it cheaper but most RWD options are not aluminum. Turbo's and related plumbing also add to weight. At 400hp you also have to make sure the trans will hold it.

Bench racing right now...I should be at 405hp / 375rwhp. (Factory Z06 rating / what stock Z06's dyno at) with my LS1. Probably a little more with the tune and long tube headers. An aftermarket cam will do it easier and make more power but this is what I am doing. Goal is to keep factory driveability.

98 LS1 / T56 combo $2500 ($400 sold from donor)

LS6 heads ($620 shipped)

LS6 cam and springs ($108 shipped)

I still need to get a LS6 intake ($250 - $300) clutch ($300-$500), poorboy headers which are cheap 5.0 headers with LS1 flanges welded on ($300).

I probably have another couple hundred in parts like the used heads and cam, LS1 intake, misc interior pieces to sell off which helps recoup some money.

Hot linked for your pleasure. A stock C5 Z06 with a tune.

2.0 L turbo ecotec. Not cheap, but definitely light.

It will probably either get a Ford 8.8 or a Dana out of a postal jeep. rear end + narrow= no problem I have a 8.8 with a 3.73 posi and disc brakes taking up space in the garage now. A days work an $400 worth of axles away from fitting anything I want.

I'm going to agree with the turbo rotary being the lightest, most compact combo available....

BUT, and pardon my ignorance, does the FE3/F2T fit in here somewhere?

Probably not light but maybe a 7mgte from a 3rd gen supra?

tr8todd wrote: An ideal engine should produce 325 plus ft.pds of torque from just below 3k all the way to 6K. A 9K rpm Honda engine is definitely not what I'm looking for. Looking for overall drivability with lots of power and lightweight. I am helping a buddy of mine build an MGA. The floor and frame rails are rusted away but the exterior sheet metal is somewhat intact. I will have to fabricate a new center frame section and floor pan, so my driveline options are open right now. His original plan was to just drop a 5.0 Ford in there, but finding a decent drop in and go is proving to be a little difficult. I'm ready to explore some new more powerful lighter options. Want to get away from Rover V8s on this project, but I keep coming back to them. Problem is that it's getting harder to find some of the rarer pieces needed for a swap. Engines are easy. Bell housings, good trannys, timing covers, etc. are tough. Making anything over 250 HP gets expensive quick.

the 5.0/t5 swap i was going to buy is a drop in and go affair, and was last listed for under $1000. Dusterbd is on here a fair amount, very good friends with the guy that has it.
Idk if you'd want to drive down here to NC to get it, but it is a deal. The only reason I'm probably not going to get it is I'm trying to just get $500 into an engine/trans and spend the rest on suspension and such.

tr8todd wrote: Let's say your looking to do an engine swap. What is the lightest route to a legitimate 400 HP? Something with a broad torque range, rear wheel drive application, and a robust manual transmission. Consider the weight of the tranny as well, and since this is GRM, lets keep cost in mind. There has to be something better than an LS1/T56 swap, but that seems like a good place to start.

Ford 302 is about the same weight as an LS1, and that's with iron heads and intake manifold.

I'm assuming by 400hp you mean all-day 400hp, and not 5-seconds 400hp such as what you could get from a turbo D16 Honda. That wouldn't be RWD-friendly, but a turbo Ecotec WOULD be. From what I gather, you can put all sorts of interesting transmissions behind the Ecotec if you have the bellhousing from a 5-speed Solstice.

FlightService wrote: Subaru EJ25 or EZ30/36 with a stout turbo should get you there. Bellhousings would be the issue but definitely light weight. and cost effective.

Not really. You can get Subaru-to-Toyota RWD bellhousings now.

Turbo'ed Busa engine.

Greg Voth wrote: poorboy headers which are cheap 5.0 headers with LS1 flanges welded on ($300).

Dude!!!

i had an inkling that would be possible but ever got around to checking the exhaust flange angle on the Ford vs. the Chevy engines. Still seems to me that the Ford tubes would end up being too small.

Wonder if these headers would fit any passenger cars of interest. 1 3/4" tubes for $250 and no welding required.

Another fun fact: LT1 engines are a dime a dozen, now, in the wake of the LS1 superiority, and they weigh within a handful of pounds. (The iron-block truck engines weigh roughly 90lb more - getting into big-block territory!) The block may be aluminum, but there's a LOT of it, and you should be able to find 400hp with the money saved by not tithing at the church of LS1.