Best spent money on an L6

[G]

So I've been thinking about Lurch's comment from the tensioner thread about "best spent money" and whilst there are multiple topics which start "I'm going to build an engine, what should I do?", I seldom see a 'cost curve' approach taken to the question. Being as price is a key determinate for nearly everyone, I'm interested to see where the experienced campaigners would spend money, if money really was limited.

 

So if we consider someone will be rebuilding (and only had the money for a stock rebuild), a stock n/a L28 with 240z carbs which goes pretty well and will need to pay specialists to do specialist tasks (i.e. porting and machining), where would YOU spend the money if you had:

 

(a) No extra dough. Where are the cost-free little bits you can do to make a good engine, better.

 

(b) An extra $1,000

 

© An extra $2,500

 

(d) An extra $5,000

 

I guess I'm focusing on n/a builds here and maintaining an L6 under the bonnet.

 

[dat2kman]

Just think of it as "insurance"

Anything you put in, modify, or after,arket items, is all done for long term insurance.

 

If you know what to do, and there are plenty who do, and even more plenty that like to think they do, but have NFI, you can build an absolute stink hot combo, but you need to mate engine, box and diff.

 

You have already got the brakes and suspension sorted first,,, one would hope!

[G]

What I'm asking in a roundabout way, is which are the best "bang for buck" mods on a limited budget, based on the limits as above?

 

If you only had $1,000, would you spend it focusing on extractors, ignition, bigger carbs or maybe some port work? (and so on up the cost curve)

[benny]

We'll sorted su's, half decent pipes, elec ignition, lightened flywheel

[HS30-H]

What I'm asking in a roundabout way, is which are the best "bang for buck" mods on a limited budget, based on the limits as above?

 

My first mod of choice on an otherwise stock S30-series Z: A 4.44 ratio diff.

 

No, really.

 

 

Edit: And I know you're asking about engine mods here, but sorry I'd go for the diff ratio before touching the engine. 

[1600dave]

As an aside, and not an L6, but a 4.44 LSD and S15 6 speed (so close ratio) gearbox in my 1600 is by far the best mod I've done as far as lap times go.

 

With the engine, spend money on head work first, then cam, carbs and exhaust to support the head work. That's where the large initial performance gains will come from. Bottom end only needs to be modified to not go "bang". Got more money, get more headwork !

 

Depends on what you want to do with the engine too - race / street / ?

 

 

[dat2kman]

Aaannnddd,,

Tir31 on here is selling a 4.375 LSD!

[G]

..but this is my point. No-one ever costs this stuff. If you play the "what cool garage could I assemble for $250,000?" question, it's different to "what's some cool cars?".

 

The ready-made answer for L6 mods is to spend all the money on the head first, but without a decent set of pipes (because you've run out of cash), or mods to the intake side, are you going to achieve anything? For $1,000, would you be better off reprofiling the cam (at say $200), plus a cheap set of pipes ($300) and some light cleaning up of the head ($500)? To spend money in these areas, you've ignored ignition mods and, as Alan has added, you're still running standard ratios through the driveline.

 

As another example, if you're building an engine, are you better off buying aftermarket rods, rather than spending nearly the same budget on cleaning up the old ones?

 

Lurch raises a valid point about spending the money you have in the right places as nearly all of us are purse-strapped in our decision making. I'm just interested in teasing out the question to see how people would spend their money in the real world, given financial restriction and the added problem that you can seldom modify one thing alone which will result in tangible improvement to the whole.

 

If you are building a stock engine for a client and he/she is prepared to throw another $1,000, $2,500 or $5,000 at it, where would you spend the money for that person?

[44014]

$ per hp can't go past this.

[G]

I agree, but it's also why I said n/a up top.

 

[gav240z]

I can understand where you're coming from with this. I've given it a lot of thought in terms of best bang for buck. But also what I want from budget etc.. I'm still on the fence here in that I'm considering spending $10k+ on the motor or just doing a simple refresh and looking for ways to retain drivability but maybe make the car a little more alive.

 

Let's assume a standard 240z, L24, points distributor, standard SUs and exhaust system.

 

Assuming the motor needed a rebuild anyway...

 

1. L28 block, if you need new pistons anyway overbore to 3.0L

2. High compression flat top pistons.

3. N42 head - if not doing anything other than clean up. P90 if you have budget to make higher compression.

4. Rebuilt SUs with suitable needles for bigger motor (consensus seems to be SM needles for L28). Or if budget allows Triple 44 Mikuni's.

5. Port match N42 head and SUs or Triples if available.

6. Electronic ignition recurved to suit camshaft profile.

7. Mildly aggressive camshaft profile.

8. Performance valves with seats cut to suit. Maybe tidy up valve seat / throat area to ensure smooth transition.

9. Exhaust manifold from Stewart Wilkins

 

Then I'd look at a 260z close ratio box (2.9 first gear) with a tall 5th gear for freeway cruising and perhaps consider an LSD 4.1 or 4.44 ratio diff.

 

I'm guessing that would total maybe 6-8K depending on options you chose.... Maybe yield around 200-230 HP at flywheel?

[44014]

That horsepower level can be reached quite easily with triples,cam,exhaust and electronic ignition.

 

[theremm]

My vote would be electronic ignition upgrade (pertronix is easiest) and headers and exhaust system.

 

These no doubt would produce the best bang for buck HP/torque increase for a standard N/A (and points) motor.

 

Gaining the maximum power from other mods is largely dependent upon addressing these two items first anyway.

[44014]

$1000 : second hand set of 40mm triples

$2500 : second hand set of 40mm triples extractors/exhaust and 280zx elec ignition

$5000 : second hand set of 40mm triples extractors/exhaust , 280zx elec ignition, lumpy cam and port match, shave head for more compression.

 

[gav240z]

Although costs aren't exactly laid out in front of you I still think 1 of the most informative sites for an S30z enthusiast is Z-Garage which has been around since 97 or so I think? I seem to recall finding the site right after I got into S30z's and was still in high school. It was hosted on the now defunct Geocities  .

 

http://datsunzgarage.com/

 

This section in particular is useful if you plan to retain the SUs and want to see what you can achieve.

http://datsunzgarage.com/dyno/index.htm

[wildy55]

Or you could look at it from this angle...

If you give your car to a better driver, your car will go faster for free.

So spend that money on becoming smarter behind the wheel and on the pedals.

Works every time!

[PB260Z]

Or you could look at it from this angle...

If you give your car to a better driver, your car will go faster for free.

So spend that money on becoming smarter behind the wheel and on the pedals.

Works every time!

 

Very wise words indeed.

As a journalist once said to me "an average car driven well will beat poorly driven Ferrari every time"

[C.A.R.]

[44014]

Very wise words indeed.

As a journalist once said to me "an average car driven well will beat poorly driven Ferrari every time"

 

Finish line is always on the straight....

[luvemfast]

I think the question has nothing to do with lap times, suspension, brake or any other mechanical mods besides the L6.

 

Basically the bottom line is.

Power is made in the head, reliability is in the bottom end. (of course there are exceptions)

Fuel, air, spark.

Flow more, go more!

[G]

Hmmm.. that went well.

One person answered the question and Lurch ate popcorn..

 

[zed74]

Hmmm.. that went well.

One person answered the question and Lurch ate popcorn..

IMHO

Go with Alan's opinion for the 4.44 diff ratio - quick/simple & cost effective performance upgrade.

 

It's uncomplicated & guaranteed a result

[Roberto]

Not all zed drivers are race car drivers.

 

The OP was asking about L6 mods, power and cost effectiveness.  Nothing to do with lap times on the track.

 

That means, I agree with Luvemfast. 

[44014]

IMHO

Go with Alan's opinion for the 4.44 diff ratio - quick/simple & cost effective performance upgrade.

 

It's uncomplicated & guaranteed a result

 

And where is this 4.4 diff for less then a $1000?

[gav240z]

And where is this 4.4 diff for less then a $1000?

 

Not in Australia.... I've seen a few in Japan but you gotta import them and hope they are not shagged when they arrive.

 

Subaru R180 LSDs can be adapted I think I've read, not sure how hard it is?