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3.0L vs V8


Guest larkja

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Guest larkja

I have a very nice '73 240z I track whenever possible. I am going to do an engine upgrade very shortly - the L24 just isn't enough. I have spoken with a great engine builder out here in CA - Dave Rebello. He puts together a great 3.0L that puts out between 250 and 280hp with around the same amount of torque depending on cams and carburetion. The cost for the 3.0L will be around $4,000.

 

I think I'll be pretty happy with 280hp and 280torque, but I'm wondering if I should bite the bullet and do the V8 swap. I am mainly concerned with handling. The 3.0L is obviously not going to affect the balance. Unless I add some lightweight items to the V8, I'm thinking I'm going to add a couple hundred pounds - not sure if it's worth it.

 

Please help me out here.

 

Thanks

Jim

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Guest Anonymous

jim, well i have payed much attention to this site and can answer or suggest a little. with the jtr style conversion the whole point is that the engine is mounted very close to the fire wall. as well as the V8 (depending)is only going to be approx. 150lbs maybe a little more. more than the original motor. and as most of the guys here could mention if you grab light weight materials for the motor. you can get very close to the original weight and restore or come close to a 50/50 weight ratio. and if your looking for juice look around and 4400 can get you a decent little monster. my brain is going but i remember for example a very very nice 383 approx.500 horse and near equal torque. i hear the rebello is nice but you cant go werong with the chevy v8. thats my input.

 

zach

 

P.S. you can always even the weight ratio out here and there. for instance battery relocation. icon_smile.gif

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As Zach said, the weight distribution with an Aluminum head,intake,waterpump Chevy V8 can come out 52/48. Depending on what else you do (add a heavy T-56, relocate the battery, etc.) it can go to 50/50.

 

Do the Ford V8 and you can get even better F/R weight distribution.

 

Things to consider are:

 

1) How long will it take Rebello to build that 3.0L L28? I've heard he always has quite a line to wait in - because he's so damned good!

 

2) What do you want for a torque curve? I'd bet that the 3.0L normally aspirated motor will be peaky and not have abundent torque until 4000 rpm or higher. If you're racing, that's great, but on the street, IMO, that's not very much fun.

 

3) Would you be happy with doing in all the little things that a V8 swap involves. It's a fairly straight forward swap, but it's not an uncomplicated thing either.

 

I'd at least read JTR's V8 Z conversion manual intro if you have initial questions, and buy the book and read it if at all interested.

 

Cheers,

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Guest larkja

I was checking into V8s and through this forum, was linked to http://www.jonbarrett.com/index2.php3. This guy has a 350 putting out 330hp for $2,200 - seems like a great deal. Anyone here used these motors?

 

I will be racing the car so I want to be sure I have something that is pretty bulletproof which is why I checked into Dave. His backlog is 4 to 6 weeks. I can live with that but want to make sure I'm getting something I will be happy with in the long run.

 

I will be running the engine at high RPMs for extended lengths of time - a little lower with the V8 because of the power band. Yes, the 3.0 starts building a lot of power around 3500rpm.

 

Still searching for tips. BTW, are there any V8ers in the Bay Area, CA that I can speak with?

 

Thanks

Jim

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I have to agree w/all that's been said thus far-and then say it again/but in my own way.

 

From what I've seen/read-the L28 (tho be it an inline 6) is actually a heavy duty built 6 & weighs more than you think it would. This is the reason you only gain about 150-160lbs when doing the JTR swap.

 

When you put the numbers on paper of the weight savings by using alluminum parts that Pete mentioned/you get pretty close to stock spec's.

 

And when you're that close to stock spec's-the amount of torque that a SBC or SBF can make at low RPM's-will far out weigh any torque that 3.0 (or it's cost) can put out.

 

For $4400-you can get a rock solid/rip-snorten pavement pounding V8/Z...dont forget the brakes/suspension/tires to match the new found power!

 

What's even better-is your mild/moderate street V8 will be by far more dependable than a tightly wound 3.0. Performance parts for an american push rod V8 are less expensive than hi/po go parts on the 3.0; so any repairs to the V8 set up (if/when needed) will be cheaper than when you break something on the 3.0.

 

You may pay a little more up front on the V8 set up if you include brakes/suspension/tires-but in the long run there wont be the constant expense of repairing hi/po parts on the 3.0; put the pro's/con's on paper & then weight them against your total adjusted budget from 1-3 years -vs- power & performance gained. Then make your decision.

 

BTW: if its 3.0 liters you want/why not go the Scottie GNZ route-use a Buick V6 & turbo charge it...great gas mileage & all the power you can afford. Or use a 4.3 V6/those V6's are known to be excellant little power houses...just some more things to think about!

 

Kevin,

(Yea,Still an Inliner)

 

[ June 17, 2001: Message edited by: Kevin Shasteen ]

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Hrm - you're racing this so I must ask, what do the class rules say about engine swaps? If this is simply open track for fun kind of thing that great, otherwise even the 3.0 might not be allowed.

 

We've had postings of this sort in the past occasionally. Usually it's someone interested in what a 3.1 will do for them. A few 3.1 dyno pulls have been posted too and frankly for the money spent the power has been disappointing IMO.

 

However, if your budget is firm @ $4400 or so then a V8 might not be for you. I had a pretty solid motor built for my car - $4400 was around what it cost - no carb, distributor etc.. Then I added a T56 @ $1700, now I've gone nutz with brakes, wheelstires, and on and on. Nedless to say I've blown your $4400 budget easily. However with as much power as this will make I'd have been crazy not to upgrade these things. Since you take your car to the tack you may have already done much of this or intend to anyway so perhaps that's no big deal?

 

Cheaper motors than mine can obviously be had. So can cheaper transmissions if you shop around. GM makes a couple of nice aluminum headed crate motors that make well over 300HP and can be upgraded further. Careful hunting for a T56 could get you one for as little as $1K. Little things will eat up at least another grand IMO but say $6K and you're done if you've already got brakes.

 

Anyway, just letting you know there's more to it than tossing the motor in. Yes, it's a little more work but the power will be incredible! I liked my car with a 2.8 and triple Webbers but I have no doubt that 450 or so horses will be much more fun. Just imagine having traction and braking as your problems rather than acceleration! And if I wish I can upgrade from there icon_eek.gif

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As Pete and a few other said you can get the weight of a SBC within a few pounds of the original Z motor. You said you track it and it will spend a bit of time at high RPM's so I will assume that you are not drag racing so handling matters.

 

If you use the JTR method the engine will be back against the firewall and completely behind the front axle. Remember that the Z engine is very tall and long where as the Chevy is quite short and low because of the V configuration. This means that you will also have a lower center of gravity and improved polar moment which will improve the handling of the car.

 

I wonder if what engine is in this one? http://www.reinaintlauto.com/gto413.html icon_biggrin.gif

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Larkja, if $4k is total budget and you race regularly stay with the L6. If budget might have room V8 is a LOT more attractive IMO. For $4k you can build a aluminum head/intake/water pump/headers small block that will have more power/torque than the rebello and do it easily all day long. But I doubt you'll get your tranny setup ideally for your roadracing within above budget hence my suggestions for below/above $4k. IMO folks think they'll be at high rpm's a lot when roadracing but once a V8 is in their it takes v. little time to accelerate so you're either accelerating fast thru gears or braking. Power band is nice'n'low so no excess rpm's needed which is what wears an 'ordinary' motor. NOT floating at higher rpm's as speed gradually rises at 100+mph. It happens NOW and it really is eyeopening. And that's my take with my lighter than OEM 280zx still with full interior etc that weighed in at 50.0/50.0 with rear spare and all tools yanked for an event. So actually a rear wheel weight bias. Battery is mounted mid car as well.

 

Having said that, I daily drove and roadraced a 327 in my 280zx that I had minimal dough into, ~$1kUS and had no problems with it. AFter 4 yrs it was yanked and actually had less than 1.5 thou wear in some holes and never bored out icon_smile.gif The '98 350 bottom end in it now was ~$400US and is doing just fine. Top end was probable close to $1750 or so US on the 350 if you were to buy the parts new but I've benefitted from patient/shrewd shopping amongst drag racing 'take-offs' which are in as new condition usually. Many don't have the time or patience to do this which is why I suggest the <$4k/+$4k ideers up above.

 

quote:

Originally posted by larkja:

He puts together a great 3.0L that puts out between 250 and 280hp with around the same amount of torque depending on cams and carburetion. The cost for the 3.0L will be around $4,000.

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Ross brings up some good points regarding budget. A 400hp car will likely need more money spent on brakes/suspension/driveline than a 250hp car will.

 

Turnaround time is another issue. I'm sure you could have your old engine yanked and the 3.0 in the car in a day. I wouldn't expect such speed doing the JTR swap. (though likely it'll take you less than 11 years... *nudge pete*) icon_biggrin.gif

 

It really comes down to what you want out of the car. Either engine will give you a very quick car. One will produce high rpm torque, one will produce lower rpm torque.

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Guest Anonymous

I agree with the above as well. Also just to emphasize what Jim said about class rules, depending on what your doing trackwise, you may end up in a class that makes it hard to be competitive with the V8 in the Z without spending a boatload of money. Same deal with the 3.0, check your class rules unless as Jim said your just going on open track days. If you have everything else the way you'd like it on the car, and 4K will buy the motor to bolt in and run, then that might be the more cost effective proposition for that amount of HP.

 

Good luck with it,

 

Lone

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Guest larkja

Thanks for all the replies. My budget isn't $4K - that's just what I was planning on spending for the motor. Installation, tranny, motor, carb, headers, JTR kit, etc - I was planning on spending no more than $6K.

 

A reliable and consistent 350hp and 350lbs would be fine for starters. I don't need a wicked fast car right now. I'm really hoping one of you can give me some input re. the site I found on the web - http://www.jonbarrett.com/index2.php3. Also, I do not want an automatic. I'm looking at either a 5sp or 6sp - any thoughts?

 

Also, with all that heat near the firewall, do things in the ****pit get a bit warm?

 

Thanks again

Jim

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Guest larkja

Thanks for all the replies. My budget isn't $4K - that's just what I was planning on spending for the motor. Installation, tranny, motor, carb, headers, JTR kit, etc - I was planning on spending no more than $6K.

 

A reliable and consistent 350hp and 350lbs would be fine for starters. I don't need a wicked fast car right now. I'm really hoping one of you can give me some input re. the site I found on the web - http://www.jonbarrett.com/index2.php3. Also, I do not want an automatic. I'm looking at either a 5sp or 6sp - any thoughts?

 

Also, with all that heat near the firewall, do things in the cabin get a bit warm?

 

Thanks again

Jim

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a low miles used LT1/T56 install would suit that perfectly and have change left possibly. V. strong long running roadracers amongst local soloI friends running 4th gen fbodies. 275hp stock and easily bumped out nicely without sacrificing manners/mpg etc and the EFI is practically a free bonus when looking at the value one gets. How else can you get a 300+hp setup (easy/cheap mods) COMPLETE with rock solid 6spd trans for $4k or less. My dad's was less and complete rolled/hit cars with perfect low miles powertrains have been seen/inspected bought at $3500 so one could almost profit (ignoring time in) on such a purchase.

 

If I was starting from scratch or even close to it with minimal dough in my powertrain I'd do that leap in a flash. I gotta get the pics of my dad's 240zlt1t56 scanned in here....on my list somewhere icon_smile.gif

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I'm not sure that any of us have used that builder. My builder was a Ford race motor builder out West that also does Chevy when no Ford guys are looking icon_smile.gif

 

Looking at that site the biggest "issue" I'd have is his use of iron heads. Aluminum heads could save you quite a bit of weight! In a race car weight is your enemy so aluminum heads would be a nice thing to have. You could certainly upgrade to those later if you wanted - his prices are attractive. You might want to call them up and see what they can offer in the way of aluminum.

 

Look closely at GM crate motors too. Warranty and aluminum heads delivered to your door. The ZZ4 and the new 383 motor are pretty nice and would meet your HP requirements. Expect to have to buy a flywheel, and to spend $250 if it's SFI rated.

 

If this is a track car only and not drag raced a T5 might work fine for you. If it'll be driven on the street, highway cruised, and beat on from a stop then I'd look for a T56. The T5 weighs noticablly less FWIW.

 

Some incidentals to keep in mind:

 

Radiator - $200 (aluminum)

Distributor - $100 and up if not included

Ignition - $150+ (I'm just using the distributor though - rev limiter and multispark later!)

Clutch master - $75? It's a Tilton unit.

Aluminum water pump - $150 or more (new)

Carb - $150 or more

Fuel lines and fittings - $150 or more (guesstimate)

Shifter - $100 and up for aftermarket stuff

Starter - $200 and up (my OEM was $250!)

Alternator + pulleys - $250 and up

Driveshaft - $???

 

You get the idea. There's more to this than a motor and trans. If you've not got an R200 you'll want one - with an LSD if possible.

 

Just make sure you know what you're getting into an dbe prepared to blow the budget. IMO it would be worth it icon_biggrin.gif At least buy the JTR book and see what it takes. It's not really a weekend project like a 3.0 might be but in the end you'd have some serious power!

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Jim (larkja),

Here is a neat little article on a 2.9L dual SU Datsun motor that was built on a tight budget: Norm's 12-second 240Z.

 

I agree with most people that a V8 is the best way to go for outright "easy-to-obtain" horsepower. However, a N/A L-series swap would be the easiest to perform. A turbo L-series is also another option, but can easily become just as involved and pricey as a V8 swap. Ask yourself what you really want to acheive, how much work you want to do, and how quick you want it done. Personally, I wanted something that was very fast, fairly cheap, and could be done in a couple of months. Hence the reason I chose the V8.

 

-Andy

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I'd agree that 400hp out of an L series isn't a bolt on affair, or isn't if you have any notions of longevity. Forged pistons are pretty much a must at that point.

 

The torque peak of the 82 280zx turbo engine stock is 2800rpm, which is pretty reasonable for the street IMHO.

 

Pete brings up a good point about character, and drivability. Some like peaky engines, some don't. (I'm one of the former, BTW) It all comes down to what you want out of the car, and how hard you want to work to get the most out of the car. icon_smile.gif (row those oars!)

 

Moving on to Norm's 2.9L. Proof that the sub par dyno results we've seen from the 3.0L's are truely sub par. If Norm can turn out 12.88 with a 2.9L NA and a lot of tuning, we do get a glimpse at the potential of a 3.0L NA if set up correctly.

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quote:

Originally posted by Drax240z:

...The torque peak of the 82 280zx turbo engine stock is 2800rpm, which is pretty reasonable for the street IMHO.

 

Reasonable, yes, just not what I'm into. And what is that torque? I have a car that cruises at 60 at about 3K in 5th (92 Eclipse GSX) and there's lag to be had - you need to shift down to accelerate, unless you have seconds to wait for the boost to build. This BTW, is NOT an optimized system, just a relief type manual boost controller which is WAY better than the stock bleeder valve. I know a larger turbo'd engine that's optimized for low-mid range would be different.

 

quote:

Originally posted by Drax240z:

Pete brings up a good point about character, and drivability. Some like peaky engines, some don't. (I'm one of the former, BTW) It all comes down to what you want out of the car, and how hard you want to work to get the most out of the car.
icon_smile.gif
(row those oars!)

 

As you can see from my above comments, I'm one lazy SOB who favors that latter! I don't want to have to row those oars! I know, the British sports car guys get all macho about how only good drivers can make an underpowered, tractor-engined 50s/60s British sports car go fast around a track. But to me, I don't care. Sure, that show's skill, but there's only so much fun I can have doing that on the street. On the street, you don't have the opportunity to be driving 10 10ths all the time to be able to have that fun. And here is where my lazy butt with a broad torque banded engine in a light car has some fun - be in ANY gear, at just about ANY rpm, and hit the gas. The result - a big kick in the back! Now THAT's MY idea of fun.

 

BTW, there was a really good quote in the recent Road & Track talking about how the old Porsche people used to say cute things about the crazy handling of the older 911s and how it was just a bunch of rationalization (my words). (You know, the oh-so-safe, extreme lift throttle oversteer.) Something about how the newer Porsche doesn't need all those rationalizations.

 

Just my point of view.

 

quote
Moving on to Norm's 2.9L. Proof that the sub par dyno results we've seen from the 3.0L's are truely sub par. If Norm can turn out 12.88 with a 2.9L NA and a lot of tuning, we do get a glimpse at the potential of a 3.0L NA if set up correctly.

 

No doubt a hell of a feat! Kudos to Norm.

But what are the street manners? The goals of a street beast are much different than those of a drag car. A really tweaked peaky drag car is no fun on the street, IMO. 12.88s are definitely faster than most cars out on the street, but I want the ability to do it quicker later on once I get used to a mild V8. Bolt on some different heads, a little bigger cam, and a very streetable 400+ NA hp is easily within reach.

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Guest larkja

Great info from everyone, thanks. BTW, how much power can a stock LSD R200 and half shafts handle? I am looking at the LT1/T56 combo - a little over 300hp and lbs. My tires and wheels are just fine - 225/50/16s - but I also know I'm going to need to upgrade the brakes as well - cross drilled, 4 piston calipers and rear disks. Tracking the car is great but it's no fun when you can't stop.

 

Jim

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