Nihilanthic

Yo! New to the LTx/LSx world, I've had a GM V8 before (L98 in a IROC-Z) and Im about to take a step up in terms of chassis and top end. Well more like actually have some... damn TPI.

Anyway, Im gonna be doing one of those v8 swaps into a RX-7, sure to **** off many a ricer and make many people jealous because of how much I can do for how little. 2800 lbs and 4.10s stock are hardly a bad mix. Oh, and the swap is bolt in now. 1986-1992s have nice, big engine bays, even bigger than the 4th gen Camaros we get our engines out of. I like to think of it as the new "Cobra" except its a shadetree mechanic job, not something you get some Mr Shelby.

Anyway, Ive seen online pullout LT1/T-56 and LS1/T-56 engines available. I notice the LT1/T-56 pullouts are 1100-1700 dollars cheaper than the LS1s, and the LS1s put down about 300 whp.

I was wondering if for the amount of money Id save going with the LT1, if I could make or break the power the LS1 would be putting down... so about 300+whp at least is my goal, but more would definitly be welcome! Also, the car is very light and has short rear gears stock... 3.9 with the N/A rear, 4.1 w/ the turbo rear Im gonna get later if I dont find one that has it) so could I build the powerband with that in mind at that price level too? You generally pick your rear gears to go with the engine, but unless I get some welding skills and put a cobra pumpkin into the IRS I have no way to get lower gears, plus Id end up needing 4.10s at least, anyway. All the gear options for those cars are numerically high becuase of those torqueless rotaries they were cursed with stock

Also, I think Kukri posts on LS1tech (not sure which subform) too, he has a RX-7 of the same generation Im going to build but it has a SBC. Id go that route but I dont know an easy way to find a SBC w/ a T-56 pullout thats already running (I'm being lazy in the beginning, I want to drive it ASAP!).

Anyway, first post, its nice to meet the LT1-LT4 mod forum! I've lurked long enough

WhiteSSP

You COULD make the power of an LS1 for the extra 11-1700 bucks, but why limit yourself. Besides, an Ls1 is also lighter than a LT1, and is a MUCH better starting point.

Nihilanthic

So, Id honestly be better off just saving up for the LSx from the get go?

Weight is hardly an issue - theres a guy who retained PS, AC, and has a LT1 in his RX-7 and hes 60 lbs heavier.... on the rear axle. Im just looking for honest answers on performance.

If you RELALY think I'd be better off just waiting on that extra 1K or so to get a LSx pullout, well, thanks for your input. Still, LT1s do have an awesome sound... dayyumn.

Chris95Z

iTrader: (3)

i think if you plan on leaving both realtively stock go with the ls1 but if you plan on doing heads and cam you got a beast either way.

omaha stylee

either motor you go with you will be happy i can guarantee that...

Nihilanthic

Im going to mod the motor down the line... its in a RX-7. Whats the point of leaving it stock! As light as that car is (~2700 with a LSx and T-56!) and the fact that to START with I got 4.10s in the rear!

I was curious as to what would be better to start out with. Im not going to IMMEDIATELY do serious mods to it, I wanna get it in and do a few things to get it more fun. Assuming a CONSERVATIVE 230 whp through the T-56 in a RX-7, Id have a 13.3 second car (assuming I get good tires under it) and it would hardly need a lot of more power to get it seriously fast.

I know with a LTx block I'd have to go get 4 bolt splayed main caps and the block machined for them if I got the itch to go take on Poopras in highway runs, but OTOH I also know it seems to be strong to like... 550 hp. Not sure if thats flywheel or drivewheel, though... but by then Id have a screamer in such a light weight car at any rate.

Hmm, I think Ill try to clarify my question here, sorry Im so garbled:
I wanna put in an engine, and if its a LT1 a few easy mods to start with (it'll be a pullout before it goes in the car, anyway), and just get it mounted in the car and work out the clutch hydraulics and such, and start enjoying it. Its a BOLT IN swap if anyones interested, btw.. www.grannysspeedshop.com (no Im not related at all)

I figure 300 whp in a 2800 lb car would be enough to keep me happy and let me decide if I wanna go with a lil more N/A (Id probalby stop at 400-450 whp) or get a Turbo or centrifugal blower kit, get the block machined, forged internals and go for ridiculous power.

Also, just incase anyone was wondering, the stock fenders allow 235 (245 with some tires)F 265 R, and bigger ones that are cheap can bump it up too 3xxf/3xxr depending on what you get. The turbo rear is strong as hell (9.42's with a 1.3 60' anyone? Btw, it was a 3100 race weight 383 stroker) and the brakes are 4pots w/ vented discs - so the chassis is hardly incapable of handling this. Also, the way the engine bay and chassis is set up the engine is behind the front struts, so even a iron block wont throw off the weight if its behind the front wheels, and the rest of the car is as if it was MEANT for a powerful v8 in it. The engine bay is HUGE!

Oh and one last thing: LOTS of class here on this forum! Haven't seen any LSx/LTx flaming and nobodys mad that Im not putting it in an F-body. damn shame many other forums dont compare.

Jordan57

well, straight up, you will do exhaust w/ headers on either motor. Probably a cam swap before the motor goes in, with springs, retainers, lifters, pushrods, etc and the tune to go with it. Also, you're gonna need a clutch too. With an LT1 setup, you might make 360rwhp+, with an LS1, some setups have cracked 430rwhp+ with fast 90mm intake/tb etc. With the light car, you can go really radical with the cam. The heads on the LS1 are great stock and flow .300+cfm, whereas LT1's leave much to be desired. Cam-only LS1's with 3100 lb race weight are deep 10 second cars, whereas LT1's hover right around 11.4 with a max effort setup. Don't forget the clutch you will need to hold this beast. I would personally go LS1, do a trex cam swap, fast 90/90 setup, headers, tune, and make big power. With an LT1 you'd surely have to invest in heads, with a really good port job, welded/ported/fabbed intake, oversize valves, and some good rods/pistons to push the rpms you'll need to take advantage of the radical cam. In the end it will cost less to do the LS1. Running down big HP supras are a head swap away. just my .02.

Nihilanthic

Well, Jordan, thankya for that. LSx RX-7s are growing in number and kicking TONS of ***. Guess I'll be one of them. Being light as hell is *VERY* nice.

kukri

iTrader: (9)

What's heavier 6.0 Iron Block Vortec or a 5.7 LT1?

Nihilanthic

They'd probably be about the same, unless the 6 liter has iron heads. Both are iron block aluminum heads IIRC.

aggiez28

iTrader: (19)

i have a drop out ls1 for sale. email me if interested

brook

Nihilanthic

Im probably not going to be buying anytime soon... I made this thread so I could begin making plans and what to start looking out for. Thanks though.

WhiteSSP

An LS1 weighs 150lbs less than an LT1, and will make more power. Really, IMO, there is no consideration if you have the money. And weight is always an issue, it will lower your ET's, improve your trap speeds, lower your braking distance, improve your handling, improve your gas mileage, and put less of a strain on the rest of the drivetrain. Besides, would you rather have a 240whp 2800lb car, or a 300whp 2600lb car with a lighter front end ultimately equally drastically reduced 1/4 mile times. There is absolutely no way you'll ever take 150lbs off of the front end of an LT1 in the rx7.

zigroid

iTrader: (22)

the only thing LT1s have on LS1s are 5 bolt cylinder heads and the sound. oh man do they sound good.

with an LS1 you have:
lighter weight
better designed cylinder head just to start with along with MANY more aftermarket options
better intake manifold
no crappy optispark
stronger bottom end stock
just overall better engineering
not to mention you can make very large cube LS1s whereas LT1s are limited to 396 to 99% of people.


my fully ported LT1 casting cylinder heads flow 272 max at .600" lift. good for an LT1, but weak for an LS1. fully ported LT4 castings have a tough time seeing 300 cfm. not to mention a bit of the head flow is lopped off when you bolt an LT1/4 intake on top of them.


I would go with the LS1 without a doubt.

edit: and to answer your very original question. on an fbody for 1100-1700 in mods (which im assuming was the price difference between an LS1 and an LT1 you looked up) should get you to 290-300 rwhp if you spend the money correctly.

Dragframe

iTrader: (14)

i would buyt he ls1 if ya could.. but then again do to the lt1 like i want to do to my car (that i may be getting tomarro)...

gapless rings.. full forged bottom end. 8.5:1 compression. LT4 or after market heads that are ported and flowbenched so all ports flow equally. Then do the same for the intake (LT4 or aftermarket intake). Ask Crane or comp what would be a good cam for supercharging. Get that. lol. Then put 15 pounds of boost from a turbo or s/c. gonna need comp reprogramed and tunned (thats a given). and big ole injectors. Im told way way way over 700 rwhp with this setup. that would make your little rx7 strait SCARY.

You could go the same route with the LS1 of course. The advantages there are its lighter... and the heads are already awesome. But when you do a ground up build, the advantages stop pretty much right there.

Nihilanthic

The way you can mount engines (even our v8s!) in a RX-7 mean its basically a "Front midship" design. Ive seen LT1s be tail heavy... this is WITH PS and AC retained btw.

Therefore, weight isnt much of an issue, especially with me losing 1. the oil cooler 2. the battery to the pass. side bin, or hell the hatch and 3. getting a bunch of power! Kukri's SBC RX-7 kicking a STi and Z06 in the *** on an autocross on not-that great tires and coilovers only supports just how good this chassis is! I think of it as a pre-assembled kit car you can get for a few hundred as a roller (if not just $100 even!) and 1K to a few grand for a running one.

Anyway, if 1-1.7K only get me to 300 whp, then it really seems to not be worth it. I saw some 'cam only' 350 whp guys... guess that wasnt ALL they spent, needing at least pushrods, lifters, RRs and spings/retainers/etc.

Again, I gotta just remark at how civil and classy this forum is... still havent gotten a flame, and Im having people in the LTx forum tell me the ups and downs of their own engine. *BIG* Diff from the rotards on a RX-7 forum even hearing about you swapping an engine

Jordan57

to clarify 1700 dollars in mods, would go something like this on an ls1
-fast 90/90 intake/tb
-trex cam w/ springs, retainers pushrods, lifters
-LT headers
-underdrive pully
I assume you will be making your own air intake setup. Also a tune, clutch, aren't bad ideas either. Correctly tuned, that'd make close to or over 400rwhp (depending on accesories being ran, drivetrain losses etc). Also this is +- a couple hundred bucks.

1700 bucks into an lt1
-Lloyd Elliot LE1 Head/Cam package
-tune
-LT headers
This would put down right around 350-370 on the high side of the scale from what I have seen.

WhiteSSP

And neither of those would cost 1700 dollars, except maybe the LS1 package. You need alot more stuff than you think when you end up doing heads/cam. All of the little **** nickel and dime's you to death. Sure the LE1 package is only what 1200 bucks? A good tune from a reputeable tuner is $500 bucks. Headers are another $400 if coated, and then you need a y pipe ($150 if an offroad pipe), and a catback or a cutout ($250 for the cutout installed, $300 for the catback). Not to mention the gaskets you'll need (Head gaskets, intake mani gaskets, header gaskets, exhaust flange gaskets) better head studs/bolts for the heads, better head bolts for the headers, for the manifold, etc. etc.

With an LS1, You'll probably need block hugger headers, and a custom exhaust (same with an LT1 so its not like you're acutally losing all that much), and other than that you'll have 300-320whp, and probably 28mpg city (they can get a 3800lb car to 22mpg city, they can surely get a 2600lb car to 28mpg city), not to mention the car will have more rearward weight bias (always a good thing unless the motor is behind the rear axle), and the ablilty to make more power for equal money (400-430whp with a cam swap compared to what, 360whp for the LT1?).

The LS1 is just a better motor all around, its stronger, lighter, makes more power and torque THROUGHOUT THE ENTIRE RPM BAND than the LT1 (no LT1's dont have more low end torque, they just have no top end like the LS1). The only downfall is that the initial cost is more, but after modifications producing equal power from both motors, the LS1 is a better choice.

Jordan57

Are you serious? If you paid 500 dollars for anything other than a complete dyno tune and session, you should go see a doctor to check your ******* out. It's def feasible to do this, few friends have done this setup, with neglidgible variances. Here is a breakdown....1200 for LE1 setup, uncoated pacesetters (coating is a waste of money bc it flakes off, stainless steel is the only way to go)- 250 off ebay. Tune-150-200 from pcmforless, madz28 etc. The only thing else is custom exhaust by a muffler shop, bc no y pipe meant for an fbody would fit an rx-7. Plus cost of mufflers, fab work...maybe another 200 or so depending on rates per hour, mufflers, how extensive the design is. The ls1 is a no brainer, and seriously, if either motor put out only 330rwhp in the aforementioned form, something is definitely wrong. LS1-400+ RWHP....LT1-360-370ish RWHP