Ideal power for a S30

[logan1]

Well i have been debating about swapping out my 2.4 L6 for a built 355 or a 383 stroker. But before i go any further with my idea i need a little input from you guys. The reason i am going with a Gen I/II Chevy is because they are the best bank for my buck.

 

So here are the question:

 

(1) In your opinion what is the ideal power (HP & TQ) that you would put down for a 80% street and 20% track 240Z?

(2) What engine would give me the best power to weight ratio without breaking the bank?

 

I have been told that a 383 are really built for low rpm torque and my 240Z being really light would have severe traction issues. All guidance is welcome.

 

thanx

John

Edited March 21, 2010 by logan1

[RTz]

Even a stock, 185 HP SBC, will cause traction 'problems' with an otherwise stock S30.

 

I've seen a very mild, very budget built, 355 do consistent 12.3's in the quarter. That's Viper territory. You could roll into the throttle in 3rd gear and both tires would spin up... at 60mph.

 

You'll have to decide how far you want to go with the rest of the chassis and drivetrain before you can make a decision on practical power limits. And, of course, for some people, stupid power is still not enough. Only you can decide when enough is enough.

[DavyZ]

I've seen a very mild, very budget built, 355 do consistent 12.3's in the quarter. That's Viper territory. You could roll into the throttle in 3rd gear and both tires would spin up... at 60mph.

 

You'll have to decide how far you want to go with the rest of the chassis and drivetrain before you can make a decision on practical power limits. And, of course, for some people, stupid power is still not enough. Only you can decide when enough is enough.

 

 

Ron, I want to use the whole post as a signature, seriously. That was really poetic! Great advice too

 

 

Logan, Ron is correct about the power. The problem is that you will eventually get used to the power and speed. That means doing more modifications later as well. None of these cars is truly ever finished in my opinion. If you build a 355 or 383, it will make no difference in the long run, for you will upgrade later on anyway. Your personal preference and what intrigues you is what you should build.

 

 

 

Davy

[Michael]

Ah, a philosophical discussion! I can’t resist…

 

Setting aside for a moment ALL isssues of handling and man-machine interface, personally I am quite impressed by the acceleration of the modern 3.5L-3.7L V6 family sedan (Maxima, Accord, Camry, Malibu, Taurus). Figure around 250-280 hp and comparable torque, in a 3500-3700 lb car. That’s a power/weight ratio of around 1/14, which would be around 180 hp in a 240Z – which was quoted above as a typical figure for a stock 350 in good condition. And keep in mind that the V6 modern family sedan has great low-end torque and silky smoothness, so the comparison with a taxi-cab, mildly-cammed 350 is all the more appropriate.

 

Like in most things, there is a “knee in the curve†of performance vs. money. Below the knee, a small increment of additional investment yields a large gain, while above the knee, adding more money just chases a smaller and smaller incremental improvement.

 

For the V8 Z, there are probably two knees in the curve. The first is building a competent but stock-ish 350-based V8, with the driveline and various supporting systems. This is probably at the ~200 hp level. Experienced engine builders would laugh in unbridled derision at a 200 hp SBC, but my belief is that getting appreciably more power would require at least minimal component swaps such as camshaft/lifters/valvesprings. And while that sounds utterly trivial, wiping a flat-tappet cam on an otherwise fresh engine is a perfect way to wound your ego and to kill your enthusiasm, turning a simple project into an interminable nightmare. But assuming that this is isn’t a problem, and you’re not fazed by the typical magazine-type of 350/383/406 build, then the next knee in the curve of a V8 Z is probably around 350 hp. Beyond that you are looking at modern aluminum heads, roller camshafts, and maybe forged rods. The chassis would definitely need reinforcement, and a welding adventure includes ripping out carpet and stripping the rust-coating to access bare sheet metal… and that turns into an unavoidable rust-abatement exercise. Then there are issues of gearbox choices,, and what to do with the clutch. All of these things have been overcome by many people, but successful solutions at the >400hp level tend to be multi-year projects by folks who absorbed automotive mechanics in their teens or early 20’s, and who know their way around wrenches.

 

“If I were doing it again†– is if such things are ever possible! – I would look for a LS-series donor, and would transplant as much as possible of the engine/transmission/electronics in stock form from the donor.

 

The other big question is regarding the condition of your Z, in its present stock form. How much rust? In what condition is the suspension? What about minor things such as weatherstripping and interior paneling? Many swaps become restorations, because it’s easy to overlook minor defects in a stocker, but the owner of a swapped vehicle has higher standards for handling, braking and general “goodness†of the vehicle. So probably the first consideration before deciding on a reasonable future power level is to critically assess the present condition of one’s car. Many Z’s are perfectly serviceable for the occasional casual drive, but just aren’t good V8 swap candidates, at any power level.

Edited March 22, 2010 by Michael

[MAG58]

I'm going to say that it's completely Dependant on the driver. Personally, with the cost of an average rebuild, I.e. stock heads and block with a mild cam an induction is plenty to keep what I would think is the vast majority of Z owners scared for plenty of time to come.

[logan1]

I realize that the power requirement for the car is dependent on the driver. That was the very reason if phrased my question as "In your opinion ".

I was wanting to see what the majority of people thought was the ideal power range for a S30 and what would be the engine of choice to attain said power. Also I do realize that there is a lot of work that needs to be done to a car prior to strapping a big engine into it.

[ZR8ED]

Well here is some experienced opinion. 20+ years of modding my Z. A number that I have in my head is about the 250 rwhp mark. It is enough to light the tires, but not so powerful to instantly rip up your 30yr old suspension. Don't get me wrong, you can easily break stuff, but anything much above 300hp, and your suspension/driveline/brakes better be in tip top, and at least mildly modded, or your reliability will go down the proverbial toilet.

 

I believe I had the most fun with my z with 200ish rwph, and mild suspension/brake mods. Dead reliable, and would out handle 90% of anything on the street, and at least faster than 75% of the cars out there as well. Minimal investement, maximum reliablity, and able to drive the car 9/10th's without worry about exploding into a fiery hellish death...At 400+hp, one slip of the throttle, and it can be accident time, and you better KNOW how to handle a car. Ok ok so I am being a bit over the top, just trying to get the general idea across.

[deja]

My first engine swap into my 280Z was a stock used '94 Z28 LT1 with a cold air inlet and block huggers producing 265 RWHP. I'm running a 4L60E tranny and it turned consistent 12.9's in the 1/4. For the street it was more than adequate for me. But it had a lot of miles on the engine so I built a new 4 bolt LT1 using a GM hot cam kit to give me a little more HP. I haven't had the opportunity to test it at the drags or take it to the dyno yet but it feels much stronger than the old engine. Do I need the extra HP since my car is mainly a daily driver? Hell no. Did I want the extra HP, well that urge to get into the 11's is pretty strong, LOL. Like was said above these cars are always in a state of upgrade. I doubt I will ever say the car is done, be it performance or cosmetics.

[JMortensen]

Well here is some experienced opinion. 20+ years of modding my Z. A number that I have in my head is about the 250 rwhp mark. It is enough to light the tires, but not so powerful to instantly rip up your 30yr old suspension. Don't get me wrong, you can easily break stuff, but anything much above 300hp, and your suspension/driveline/brakes better be in tip top, and at least mildly modded, or your reliability will go down the proverbial toilet.

 

I believe I had the most fun with my z with 200ish rwph, and mild suspension/brake mods. Dead reliable, and would out handle 90% of anything on the street, and at least faster than 75% of the cars out there as well. Minimal investement, maximum reliablity, and able to drive the car 9/10th's without worry about exploding into a fiery hellish death...At 400+hp, one slip of the throttle, and it can be accident time, and you better KNOW how to handle a car. Ok ok so I am being a bit over the top, just trying to get the general idea across.

I have to agree and point out that the suspension can be as big a problem as the hp, I had a TON of fun with my Z when I started and it worked up from probably 150 to 200 whp. By the time it got to 240ish whp, the suspension was so modified that a friend remarked that the car wasn't any fun anymore because you couldn't push the limits on the street without risking death in the event of the smallest mistake. Now that my focus is track only, the hp is going way up, tires are getting much wider, etc. It's going to take some time to get used to, so my plan is to autox for a couple years before I hit any track days. Even then I assume it will be a bit of a sphincter puckering experience the first few times out.

Edited March 22, 2010 by JMortensen

[bjhines]

You might look at it another way. Build the car to suit street/track days. Get the suspension and brakes upgraded first. You don't need to go for a full coilover set, but there are some KEY components that will allow you to get the alignment correct for sport duty. Then you can start with a cheap engine and see what you have on your hands. I think you will find that tracking the car can be a handful even with 200HP.

 

That is what I did. My 1964 SBC 327 will get close to 300RWHP. I am pretty sure the chassis can handle a bit more HP. The more HP you put out the more you need upgraded suspension, brakes, and driveline, and chassis reinforcement.

[jasper]

Minor thread jack.

I have a IROC 350TPI/700R4,(approx 235 HP? stock) sitting next to the incomplete 73 240Z.

I'm starting to believe that will be PLENTY enough HP.

An LS1 would be 100+ more HP .......is it really usable/enjoyable on the street, with that much HP?

[johnc]

Having built and road raced a 325hp 240Z I agree with the posts above that 200 to 250hp is about right for a street/track 240Z. As power goes up and you make the required chassis mods the handling curve gets steeper and sharper at the limit. There's less room for error at 10/10ths and mistakes have larger consequences due to the speed involved and the track distance needed to correct that mistake. The situation is not as bad on the street because people rarely drive beyond 7/10ths on purpose.

[kamikaZeS30]

I agree with the general consensus of the thread so far: 200RWHP is about the limit for a stock S30 body. If you're going V8 though I strongly recommend doing something with your rear-differential and shafts. A Nissan L6 producing 200HP is going to behave differently than a V8 producing 200HP. Power-curve being the biggest difference, the L6 isn't going to make that kind of power (with the necessary cam and ignition timing set-up to make said power) until about 4000 RPM. Which means the car is already going to be rolling (i.e. you've gone past break-torque) that's the strength of the L6-- the engine LIVES at the mid-range. The V8 is producing OMG RIDICULOUS torque as soon as you start depressing the accelerator. Typical PEAK power for a stock SBC or LS is going to be in the 3600 RPM range (IIRC).

 

Just a bit of my experience (about 5 years or so with the S30Z, cut me some slack I'm only 25), I really like the L6 it's a great motor, has a lot of potential if you know what you're doing. I am currently undergoing an SBC 383 swap in my Z, my motor has the full pro-comp stage 2 performance dress (aluminum heads, intake, accessories, double-reduction starter, lightweight fly, billet pistons, forged rods and crank, electronic multi-spark ignition, etc.) we're talking in the neighborhood of 405 ft./lbs. of torque at the flywheel. However, I have a 4-point roll-bar, I'm welding in Bad Dog frame-rails, along with a few extra steel gussets here and there, and I've got front and rear triangulated braces and I'm still trepidatious about frame-twist with that level of power (and I don't even plan on dragging it). I am also largely paranoid about snapping shafts, the R200 as far as differential go is pretty damn resilient, most of the Nissan rear-ends are (my friend has a YJ rock-crawler and he swapped in Nissan diffs for their strength). However, your shafts are always going to be the weak-point in the system. Consider that as your starting point for, "How much power should I go for?" Good news is that with some minor fabrication the R200 and R230 rear-ends will accept a wide variety of shafts. They can also be purchased in parts yards or on craigslist for about $50~$75 USD. I am avoiding the shaft problem by staying with a less-sticky tire set-up, so rather than snap-a-shaft, the tires will just break loose and spin (not the optimal work-around, but I know this engine will take some getting used to, until then I'd like to save my shafts). Oh, and instead of using a 3.90, I decided to save some gas (and residential zone speeding tickets) by dropping to the 3.54 R200. More acceleration leeway on the freeway () and less stress on the shafts.

 

The only reason I am moving away from the L6 is that mine was pretty much optimized as much as one can with said engine. I got tired of re-tuning the Webers every two weeks (because it's my daily driver). I had an L28 bored and stroked to 3.2, running 280 degree cam .460 lift, with Triple 45DCOE Webers (I HATE tuning them, but they scream). In the end I spent more on modding the L6 than I have building and installing a V8. It took me quite a while to get to the point where I said to myself, "this just isn't enough power" and the SBC was the last engine I considered for the swap. I looked at much smaller engines RBs, VGs, VQs, SR20, but they all required a lot more $$$ than I wanted to spend on something that was going to have the same weakness as the L6: bottom end, light-up-the-tires-and-****-yourself giddyup. I am looking at a total cost of $6000 (only maybe a third of that is actual costs of building the V8, everything else is a bunch of auxiliary stuff like body work and mods that I have been putting off for too long).

 

And, before anyone asks: my L6 is going to my friend who is putting it in his triumph along with my 4.11 R200 I have now. (He finally saw the light of superiority of Japanese engineering to the British)

 

I apologize for the huge post, hope that it might help you with decisions on your swap, though.

[leroylucky]

I have a zz4 with a mild cam and a 700r4. What other mods are necessary or advised for it to be a daily driver?

[280zex]

I got my hands on 1978 280z with a v8 swap 327 sbc. I then traded the 327 for a 450 hp zz4 sbc. Not realy a good idea as the chassis is not in that good of shape. Gas milage is a joke. Even with the fattest rear tires I could fit the car is "3 seconds to death". Scares the hell outa me. Just touching the throttle at 60mph will cause the rear to go sidewayz. Lights'em up no problem. However very (scary) fun to drive. Not a daily driver tho. My turboZ with 300 rwhp with major brake/suspention/aero upgrades is wayyyyy more fun. Handles fantastic. Looks sweet too. Better to make a Datsun handle/stop better and keep the >200rwhp. No major work all the time. keep it a daily driver. Decient gas milage. I learned that a lesser hp better handling car is way more fun than a over-powered monster gas hog is.

Just my 2 cents..

[heavy85]

An LS1 would be 100+ more HP .......is it really usable/enjoyable on the street, with that much HP?

 

Yes. Since I mostly track mine anymore, the stock '02 LS1 is underpowered in the unlimited type of classes you end up in with a swap. I would really like another 50-100 hp to have a chance to somewhat keep up. However my competition include a 600 hp C6 Z06 or a certain 450 hp 1500 lb Lotus clone (roadrace car that runs 10.0 in the 1/4!!!), etc. They LEAVE me on the straights. For the street I think a stock LS1 is just about right. Get good tires and a reasonable gear ratio and traction is not that hard to find. 3.9 with crusty tires does not hook-up well. 3.7 with sticky tires make it very controllable. For autox, hp is not very important. I gained probably 100 hp with the swap and very little if any weight and it's not any faster at an autox than the L6 was.

 

Cameron

[Zinpieces]

I am building a V-8 Z myself, I'm considering destroking a 350 and building a 302. They are real screamers! My thinking is that I can wind it up faster than a 383. Torque is all good until you twist something. The car weighs nothing so the hardest thing will be keeping it on the ground!

[Tempered]

This is a great thread. I built a 327 that the shop says will have 300+ Hp and I have the 4.11 gear ratio. This scares me because my suspension mods are limited to the toyota caliper upgrade, sway bars and the tokico non adjustables with SS technique springs. Now I've never had a hybrid Z and my L6 was stock. I have rusty frame rails. All of the above posts make me think this thing will run and stuff will start to brake without further modification.

 

Perhaps all of the experienced Z builders on this post can collaborate and create a graph or FAQ on this. For example Say 200-240 hp = mild brake/ suspension upgrade. 240-300 hp = brake(wilwood or greater)/suspension/tire and chassis upgrade. Just an idea. If this already exists I apologize I am just respnding off this post alone and didn't search the site.

[JSM]

I agree with the general consensus of the thread so far: 200RWHP is about the limit for a stock S30 body. If you're going V8 though I strongly recommend doing something with your rear-differential and shafts. A Nissan L6 producing 200HP is going to behave differently than a V8 producing 200HP. Power-curve being the biggest difference, the L6 isn't going to make that kind of power (with the necessary cam and ignition timing set-up to make said power) until about 4000 RPM. Which means the car is already going to be rolling (i.e. you've gone past break-torque) that's the strength of the L6-- the engine LIVES at the mid-range. The V8 is producing OMG RIDICULOUS torque as soon as you start depressing the accelerator. Typical PEAK power for a stock SBC or LS is going to be in the 3600 RPM range (IIRC).

 

Just a bit of my experience (about 5 years or so with the S30Z, cut me some slack I'm only 25), I really like the L6 it's a great motor, has a lot of potential if you know what you're doing. I am currently undergoing an SBC 383 swap in my Z, my motor has the full pro-comp stage 2 performance dress (aluminum heads, intake, accessories, double-reduction starter, lightweight fly, billet pistons, forged rods and crank, electronic multi-spark ignition, etc.) we're talking in the neighborhood of 405 ft./lbs. of torque at the flywheel. However, I have a 4-point roll-bar, I'm welding in Bad Dog frame-rails, along with a few extra steel gussets here and there, and I've got front and rear triangulated braces and I'm still trepidatious about frame-twist with that level of power (and I don't even plan on dragging it). I am also largely paranoid about snapping shafts, the R200 as far as differential go is pretty damn resilient, most of the Nissan rear-ends are (my friend has a YJ rock-crawler and he swapped in Nissan diffs for their strength). However, your shafts are always going to be the weak-point in the system. Consider that as your starting point for, "How much power should I go for?" Good news is that with some minor fabrication the R200 and R230 rear-ends will accept a wide variety of shafts. They can also be purchased in parts yards or on craigslist for about $50~$75 USD. I am avoiding the shaft problem by staying with a less-sticky tire set-up, so rather than snap-a-shaft, the tires will just break loose and spin (not the optimal work-around, but I know this engine will take some getting used to, until then I'd like to save my shafts). Oh, and instead of using a 3.90, I decided to save some gas (and residential zone speeding tickets) by dropping to the 3.54 R200. More acceleration leeway on the freeway () and less stress on the shafts.

 

The only reason I am moving away from the L6 is that mine was pretty much optimized as much as one can with said engine. I got tired of re-tuning the Webers every two weeks (because it's my daily driver). I had an L28 bored and stroked to 3.2, running 280 degree cam .460 lift, with Triple 45DCOE Webers (I HATE tuning them, but they scream). In the end I spent more on modding the L6 than I have building and installing a V8. It took me quite a while to get to the point where I said to myself, "this just isn't enough power" and the SBC was the last engine I considered for the swap. I looked at much smaller engines RBs, VGs, VQs, SR20, but they all required a lot more $$$ than I wanted to spend on something that was going to have the same weakness as the L6: bottom end, light-up-the-tires-and-****-yourself giddyup. I am looking at a total cost of $6000 (only maybe a third of that is actual costs of building the V8, everything else is a bunch of auxiliary stuff like body work and mods that I have been putting off for too long).

 

And, before anyone asks: my L6 is going to my friend who is putting it in his triumph along with my 4.11 R200 I have now. (He finally saw the light of superiority of Japanese engineering to the British)

 

I apologize for the huge post, hope that it might help you with decisions on your swap, though.

 

I liked pretty much everything you said.

[johnc]

I have rusty frame rails.

 

I'm always amazed at folks who just ignore this and spend their money doing a Hybrid swap. Its like putting a new outbaord on your boat that leaks.