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LS1 vs LT1


BeyondAddiction
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If it were me, and I planned to be able to run stupid amounts of boost, I would choose a plain ol' SBC and build it up bulletproof. Then I'd run a low buck EFI setup, like SDS or Megasquirt, weld injector bosses into a Victor Jr. and put an Arizona Speed and Marine throttle body on top.

 

For better head cooling, you can drill into the water jacket and run a line off of the water pump to get all the benefits of an SBC2 yet still be able to run any kind of head you want.

 

For turbos, I'd run a pair of big trim T3/T4s with internal wastegates and a manual boost controller. Back it up with a built TH400 or a Powerglide (or Richmond box if you want to shift your own), and get the thickest pair of diapers you can find. :D

 

Oh, and get a 10 point roll cage, six point harness and a parachute. ;)

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Originally posted by Master Yota:

If it were me, and I planned to be able to run stupid amounts of boost, I would choose a plain ol' SBC and build it up bulletproof. Then I'd run a low buck EFI setup, like SDS or Megasquirt, weld injector bosses into a Victor Jr. and put an Arizona Speed and Marine throttle body on top.

 

For better head cooling, you can drill into the water jacket and run a line off of the water pump to get all the benefits of an SBC2 yet still be able to run any kind of head you want.

 

For turbos, I'd run a pair of big trim T3/T4s with internal wastegates and a manual boost controller. Back it up with a built TH400 or a Powerglide (or Richmond box if you want to shift your own), and get the thickest pair of diapers you can find. :D

 

Oh, and get a 10 point roll cage, six point harness and a parachute. ;)

remember this is going to be a street car tho, and has to be able to be fine cruising threw a parkinglot still, it will have a manual boost controller so i can turn it up and down from in the car, i want it to get atleast somewhat decent gas mileage when the boost is turned down
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Guest stevil

[kenny] Click here, it's your only option. :cool: [/kenny]

 

If you plan on a turbo setup, this might be a good swap to consider. ;) Should be easy to fit in the RX7, not sure if it would weigh less than an LT1 or not. I'd bet the LS1 still weighs less. Not sure on prices...

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Originally posted by Saint:

remember this is going to be a street car tho, and has to be able to be fine cruising threw a parkinglot still, it will have a manual boost controller so i can turn it up and down from in the car, i want it to get atleast somewhat decent gas mileage when the boost is turned down

Then do the setup I described but with a smaller intake manifold, smaller throttle body, SDS over the Megasquirt, and either a built 200R4 or the Richmond 5 speed. Should be perfectly streetable, and get fine mileage.

 

The parachute may look a little funny, though. ;)

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Originally posted by Hoosier Daddy:

[kenny] Click here, it's your only option. :cool: [/kenny]

 

If you plan on a turbo setup, this might be a good swap to consider. ;) Should be easy to fit in the RX7, not sure if it would weigh less than an LT1 or not. I'd bet the LS1 still weighs less. Not sure on prices...

yes there are a few of those, example: www.misred.com but like i said i want a manual right now, and depending on how smoothly this swap goes i've considered maybe doing that, but i doubt i will, most likely move on to newer cars by then, the GN engines are also a bit harder to find, it would be a nice swap for a convertable i think, just to cruise around in, not having to worry about shifting and just let the sun come down, but still able to womp all over any cars wanting a piece

 

btw, how much power can a corvette and mustangs rear end with the IDS handle?

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Originally posted by Josh Miller:

haha... dude, you're just asking for a flame war! tongue.gif He said he want's power... why on earth would he go with a ford? ... haha.... you asked for it ;)

:puts on flame suit:

 

FORD > CHEVY

 

tongue.gifgraemlins/fruit.gif

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Originally posted by Saint:

btw, how much power can a corvette and mustangs rear end with the IDS handle?

i assume you're talking about 4th gen (5th gen cars used transaxles, and 3rd gen diffs are nothing special) corvette rear diffs, so here's a piece of advice. they used 2 different rear ends in these cars...

 

the Dana 36 diff was installed in automatic tranny cars, and has a ~8 inch ring gear. the case is also aluminum, and i don't think they'd live too long between hard launches and sticky tires...

 

the Dana 44 diff was installed in manual transmission cars, and has a 9+ inch ring gear. this is the same differential installed in the viper, and it should hold up under quite a bit of abuse. it too has an aluminum case, and would probably be somewhat expensive...

 

as far as the mustang IRS diffs go, in all honestly, considering the power you want, i'd look for a 2003 cobra rear end setup. they have 31 spline half shafts and stronger internals than the earlier models. this would prolly be your best bet...

 

good luck... ;)

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Originally posted by 'No Boost For You':

Originally posted by Saint:

[qb] the Dana 44 diff was installed in manual transmission cars, and has a 9+ inch ring gear. this is the same differential installed in the viper, and it should hold up under quite a bit of abuse. it too has an aluminum case, and would probably be somewhat expensive...

 

as far as the mustang IRS diffs go, in all honestly, considering the power you want, i'd look for a 2003 cobra rear end setup. they have 31 spline half shafts and stronger internals than the earlier models. this would prolly be your best bet...

 

good luck... ;)

i think a dana 44 piece is actually used on the driveshaft to mount it to the mazda diff. so that would actually be good to use that i wouldnt have to buy a different driveshaft once i needed it to put it in

 

i know if i used a corvette/viper's i would have to change the length of the axles and shorten them, im not sure about the mustangs since its not as wide of a car, that would be nice because i wouldnt have to worry about it breaking at the welds

 

any idea how much the two cost?

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Originally posted by Saint:

i think a dana 44 piece is actually used on the driveshaft to mount it to the mazda diff. so that would actually be good to use that i wouldnt have to buy a different driveshaft once i needed it to put it in

 

i know if i used a corvette/viper's i would have to change the length of the axles and shorten them, im not sure about the mustangs since its not as wide of a car, that would be nice because i wouldnt have to worry about it breaking at the welds

 

any idea how much the two cost?

not sure on cost, but a word of warning on the corvette diffs. on the 4th gen corvette rear suspension, the half shaft is actually used as the upper control arm, so it's a solid unit and doesn't change lengths like the "plunging" half shafts used on most other cars. i'm not sure how the rear suspension is set up on an FC, but chances are, you'll need different half shafts...
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Originally posted by 'No Boost For You':

not sure on cost, but a word of warning on the corvette diffs. on the 4th gen corvette rear suspension, the half shaft is actually used as the upper control arm, so it's a solid unit and doesn't change lengths like the "plunging" half shafts used on most other cars. i'm not sure how the rear suspension is set up on an FC, but chances are, you'll need different half shafts...

ok, i know the other guys were talking about changing out the whole suspension in the back but wasnt sure which corvette model they were talking about, is it setup the same way in the C5's?

 

looks like ill be looking into the mustang's i was kind of figuring i would have to go with one anyways, just wanted to find out a little more about the corvette's

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Originally posted by Saint:

ok, i know the other guys were talking about changing out the whole suspension in the back but wasnt sure which corvette model they were talking about, is it setup the same way in the C5's?

 

looks like ill be looking into the mustang's i was kind of figuring i would have to go with one anyways, just wanted to find out a little more about the corvette's

in all honesty, i think the mustang setup is cheaper and possibly stronger. as guys start to swap the IRS with a solid axle to drag race, a lot of these rear setups should start popping up for sale... ;)

 

getting parts for the corvette setup would probably be more difficult as these differentials were never really that popular. the 8.8 (i'm assuming the parts are interchangable between the IRS and solid axle 8.8, so check on that first) ford, on the other hand, has lots of aftermarket support, gear sets, and differential choices. with the popularity of the 2003 cobra, even more parts should be on the way...

 

the C5 setup is completely different from the earlier corvettes. if i remember correctly, the transmission is actually housed in the rear differential/transaxle case in the rear of the car. plunging half shafts and a double wishbone setup are used to locate the rear wheels, as opposed to the earlier multi link setup with its solid halfshafts and trailing arms. as far as i know, prices for parts on the C5 setup, like shocks/springs and gear sets, are extremely expensive...

 

the mustang setup uses a seperate (tubular if i remember) subframe which is bolted into the rear of the car using the original solid axle suspension's mounting points, and also uses the plunging halfshafts and double wishbones. the cobra setup has been around for a while, and finding parts for it isn't difficult or terribly expenive. 2000 cobra R and 2003 cobra parts can be used to strengthen the earlier 99-02 setups, and you'll find similar parts in the 90's tbird/cougar/mark8 (MN12 chassis) cars...

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Guest relvinnian
Originally posted by Saint:

Originally posted by Saint:

[qb]i think a dana 44 piece is actually used on the driveshaft to mount it to the mazda diff. so that would actually be good to use that i wouldnt have to buy a different driveshaft once i needed it to put it in

Umm no. :confused: Dana 44 is a completely different ring and pinion, housing, everthing. You will have to have a custom driveshaft made no matter what.

 

Honestly, I've been through this whole V8 RX-7 debate so many times, and designed so many different combinations. Only a few of them were practical. If you plan on turbocharging it, and still retaining it's cornering ability, I would go with a built 5.0 with the specs Mark had mentioned (very close to my calculations for efficiency). The LT1, should you choose will be VERY heavy with 2 turbochargers and all the supporting hardware. If you plan on using an SBC, I would throw that whole IRS idea out the window and go with a cheap solid rear. The supporting drivetrain modifications required by these huge torque engines, will have your head spinning after awhile, trust me. Your issues with not being able to hook, once alleviated, will adversely affect your lateral traction and suspension geometry.

 

I came to the following conclusions when doing my research:

 

1. Turbocharged: the vehicle would only be practical from a drag only perspective. Power delivery from a heavily built, turbocharged V8 is horrible for exiting corners! The supporting drivetrain, and the massive suspension and wieght distribution changes are not practical, IMO.

 

2. N/A: This setup is practical in many applications. Power delivery from a modified LT1 (from 300-420rwhp approx.) will be much smoother, and peak power is not as high. First, to increase power further in N/A state, you will have to significantly change the shape of the powerband with extensive valvetrain, and internal balancing, as well as a high lift/duration solid roller, and some 200-220 heads at least. This setup is beautiful from every aspect except COST.

 

My personal verdict is that in turbocharged form, I would use a lightly built, and well tuned 5.0. From my calculations this setup could produce as much as 600-700rwhp reliably on higher boost, and around 450rwhp for a lower more tractable setup. In normally aspirated form, I would use an SBC, and run a fairly heafty head/cam setup (hydraulic), producing around 440rwhp, and build the engine to handle some nitrous.

 

My choice of engines was based only on wieght, and capacity for the application. smile.gif

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Guest relvinnian

Main problem is: Unless you want to use a carbeurated V8 setup (or a junkyard turbo setup), or want to spend more than 12k on building the engine. You can get that same 440rwhp from a STOCK series 4 13BT running an efficient combination and around 26 psi. Built with modified ports and clearanced rotors, that same engine will make 440rwhp @ only 18-20 psi!

 

This is all calculated using a T62-1 compressor trim on a .7 comp housing. If you were to go with a properly sized T-series, on a street port (early open intake, and highly modified exhaust), you would see as much as 450-500rwhp @ 15psi depending on the specs of the turbo.

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Originally posted by relvinnian:

Umm no. :confused: Dana 44 is a completely different ring and pinion, housing, everthing. You will have to have a custom driveshaft made no matter what.

ok sorry, its a Dana 353 rear yoke that i was thinking of

 

i already know i will have to have a custom drive shaft built, and i also have been considering an NA setup, and yes i know turbochargeing it will make it slightly more front heavy, it will be a while after the car has been up and running anyways, so by the time i turbo charge it i hope to have a 240sx to do autocross in and wont be using it for that, i will be using it for mainly cruising/drag/highway runs, i already know those things, this is why i was only asking about the capabilities of the engines and rear diff's

 

dont take this the wrong way but, i dont want a rotary(and yes i know what a streetport is), i want some serious power to last longer than 3 years and not have to worry about a small mistake blowing up the engine and have to start all over again

 

so anyways, no boost for you, about the mustang 8.8 rear end there were guys actually talking about using one of those too after working on a couger and said it would most likely go in pretty easily, i dont know of anybody doing it yet but there are some with a solid rear axle for drag racing, but i know im not going to be doing that so i still have the handling, so its looking like im going to start keeping an eye out for those or one from a new '03 cobra

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Guest relvinnian
Originally posted by Saint:

i will be using it for mainly cruising/drag/highway runs, i already know those things, this is why i was only asking about the capabilities of the engines and rear diff's

I see what you mean. I think even with a very front heavy turbo setup, and solid rear, the car will still handle great compared with your average small car. It's not as though you will have an anvil hanging from the front bumper. I think this conversion is perfect for a GT/Cruiser + killer drag car. It seems more natural that way, instead of trying to retain the that "Oh so perfect" (and not so practical) 50/50. With that much power you could use a little understeer ;) .

 

For me a GT/Cruiser car is ideally a larger more comfortable car than the FC. I like the twitchiness of the suspension smile.gif . For some reason I was under the impression that you were going to road race and wanted that suspension feel. Who knows.

 

As far as rotaries. I really could care less. I would be be happier if I could afford to throw a stroked 4g63, RWD setup in my car.

 

Have fun, and give me a ride.

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Originally posted by relvinnian:

I see what you mean. I think even with a very front heavy turbo setup, and solid rear, the car will still handle great compared with your average small car. It's not as though you will have an anvil hanging from the front bumper. I think this conversion is perfect for a GT/Cruiser + killer drag car. It seems more natural that way, instead of trying to retain the that "Oh so perfect" (and not so practical) 50/50. With that much power you could use a little understeer ;) .

 

For me a GT/Cruiser car is ideally a larger more comfortable car than the FC. I like the twitchiness of the suspension smile.gif . For some reason I was under the impression that you were going to road race and wanted that suspension feel. Who knows.

 

As far as rotaries. I really could care less. I would be be happier if I could afford to throw a stroked 4g63, RWD setup in my car.

 

Have fun, and give me a ride.

you would be surprised, with the engine staying NA, it will actually be still 50/50 and just as light, some even end up lighter than a T2, once a turbo setup would be put on it would of course offset the balance somewhat, i still think it should be in maybe the 53/47 range, no matter what its going to be fun as hell tho :D
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Originally posted by WIKD TSI:

mmmmm 2.4l Turbo goodness ;)

if thats that ford turbo 4cyl engines from the SVO and thunderbird turbo coupe i actually thought about those, cept i dont know much about them and what i did find out was supposedly that parts for them are a little hard to come by, just didnt get very good responses when i asked about them so i passed on that idea, i did find out someone i might have been able to get a rebuilt one from, not sure if her uncle still has it tho
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Guest relvinnian
Originally posted by Saint:

if thats that ford turbo 4cyl engines from the SVO and thunderbird turbo coupe i actually thought about those, cept i dont know much about them and what i did find out was supposedly that parts for them are a little hard to come by, just didnt get very good responses when i asked about them so i passed on that idea, i did find out someone i might have been able to get a rebuilt one from, not sure if her uncle still has it tho

I'm pretty sure he was still talking about the stroked 4g63 ;)
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Originally posted by relvinnian:

I'm pretty sure he was still talking about the stroked 4g63 ;)

are those the engines in the Truenos?

 

i've been looking at the SR20DET engines in the 240SX's, those are pretty cool little cars, you can get a good amount of power out of them would make really fun daily drivers

 

on zilvia.net they have some drifting in what looks like an actual track built specifically for drifting, and those fuckers really move too, from what i've read its not too hard to get them up to around 300~400hp

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Guest relvinnian

4g63 = Turbo DSM, and EVO engine platform. Very old, long evolving platform.

 

If I had the money I would stroke and completely blueprint a 4g63 and mate it to a 3rd gen chassis/drivetrain. We are talking about a 2.4l making power at 8200rpm using a custom T-66. Using custom cam grinds, and designing a beautiful turbo manifold/downpipe setup (since the engine is now facing the RIGHT way smile.gif ).

 

It would be like having a mini 2jz-gte under the hood ;) .

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