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Leon

Leon's Other 260Z

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Leon    35

I finally have a few minutes to sit down and start a log for the "new" 260Z. It all started with JCCS last September...
 
I took a trip from the Bay Area to Long Beach in the orange 260Z in September. My fiancee came along and we made a vacation out of it, staying in San Luis Obispo for the weekend and driving to Long Beach and back on Saturday for JCCS. I tried to contact one of my favorite professors from college in order to meet up with him while we were in town, but unfortunately he got the email too late. He was my Ground Vehicle Dynamics professor as well as the adviser for our FSAE engine development senior project. During the early stages of the project, while discussed ideas with my teammates and browsing an old ICE textbook, a picture of SU carbs popped up and I exclaimed, "hey, those are the same carbs as my Z!" At the time, I still had my (first) blue 240Z and the red shell. My professor overheard this and it all began. As an aside, he's worked for Dan Gurney's All-American Racers and the Benetton-Renault F1 team, pretty damn awesome!
 
Back to the present...
 
In one of his emails, he mentioned that he was thinking of getting rid of his Z in order to make space for a new race car - an F2000 open-wheeler. Of course, my interest was piqued! He was the second owner and had owned the Z for 24 years, and it had gone through many moves, across the country, and even to the UK and back with him when he went to work for Benetton-Renault. It had also gone through a few colors: originally gold, "baby sh*t brown or depending on who you talk to 'caramel'", BMW BRG, and finally Jaguar BRG. He had the paint done at a high-end hot rod shop, a 2 stage base/clear job. While the paint was being done, so was the body repair, welding in new metal in the fender and rocker, and rust-proofing everything. It has an essentially brand-new interior, including a new Nissan dash (!), new weatherstripping, new brake and fuel hard-lines, new wheel bearings, rebuilt braking system, new or re-chromed bumpers, coilovers, fat front and rear ARBs, and on-and-on. Of course, it came with some extras including: ITS L24 with Rebello-prepped E31, Tilton flywheel, coated MSA 6-1 header with mandrel-bent exhaust, 260Z Euro tail lights, a copy of the '73 FSM, binders filled with records, etc. Clearly, it was tough for him to make the decision to sell it, but it's nice to keep it "in the family" so to say. Needless to say, I'm quite happy to have this Z!
 
Before leaving SLO, we had to hit the Pismo Dunes so we rented a pair of ATVs. I haven't had fun like that in a while! I had to make sure to represent (yes, I am wearing a pink helmet :P):
 
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I rented a U-haul auto transport and borrowed my future in-laws' 4Runner to be the tow vehicle.
 
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Our fears were confirmed however, as by loading the Z ass-end first too much weight was placed on the trailer tongue. We unloaded the car and repositioned the trailer. The Z rolled out of the garage and into the street, probably the first time it has seen sun in years, if not close to a decade.
 
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The most important job of all went to Melissa.
 
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We were all just hoping we wouldn't pull one of these: :lmao:

www.youtube.com/watch?v=CH3i1Y0yXIg
 
In the end, we prevailed!

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Getting some lunch at one of our favorite spots in SLO, Jaffa Cafe, before heading back home...
 
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Oooh, nice engine bay!
 
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Damnit, who's the a-hole tailgating me!
 
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And she followed me all the way home. Can we keep her mom, please can we?
 
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And a nice sunset over South San Jose
 
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It was a successful trip and now she lies, waiting in the garage.
 
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More to come! :)

Edited by Leon

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JCan    1

Leon -

 

WOW!  Nice car.  I noticed that the engine bay and I assume undercarriage looks AMAZING!  What a find!

 

 The 260 you have, new interior (including dash!) and under carriage metal means you can spend time on the fun stuff (HP, Gear ratios, Suspension)

 

What do you plan to do to it?

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Leon    35

Leon -

 

WOW!  Nice car.  I noticed that the engine bay and I assume undercarriage looks AMAZING!  What a find!

 

 The 260 you have, new interior (including dash!) and under carriage metal means you can spend time on the fun stuff (HP, Gear ratios, Suspension)

 

What do you plan to do to it?

 

Thanks, Jim! Undercarriage is very clean, it's just how I like my Zs: rust-less! :)

 

You're on my wavelength here, nice lead in...

 

It has coilovers with Tokico HPs so I may swap the dampers out if I don't like how they pair with the springs. The PO said it was a really nice autoX setup. It also has poly bushings, 1" Front - 3/4" rear ARBs, and a completely rebuilt stock brake system. It's essentially the perfect setup for me so I'm leaving the suspension as-is for now.

 

For gearing, I got the stock 4-speed and a mystery 5-speed along with it, plus I've got another pair of 5-speeds sitting in the garage so there are plenty of transmissions to go around! My plan is to pair up a late-ZX 5-speed with a 3.9 ratio STi R180 CLSD along with Coffey's axle adapters. The car has an open R180 in it, but I haven't checked whether it's a 3.36 or 3.54. I do have a 4.375 R200 CLSD laying around, but that is slated to go into the orange Z.

 

There is no engine or trans installed currently, as you can see, so I can weigh my engine options here. The plan is an L28 with either the Rebello E31 head that came with the car, build one of the E88s I have sitting around, or find a P90 to shave. Throw in an Isky reground cam, lightweight flywheel, 6-1 header, triples and I'm ready to go! Not sure yet what I plan to do for ignition, I might just stick with a ZX distributor as I'm not eager to run Megajolt on this one.

 

Speaking of triples, I just picked up another set (thanks to Hung for the tip)!

 

DSCN1651_zps4fd6cbbc.jpg

 

At this point, I need to figure out which head and block I want to use and send them to a machine shop (any recommendations besides Rebello, SF Bay Area folks?). Then, besides the cam, I have everything else ready to go. :D

 

The vision for it is a nice driver that's somewhat quiet and comfortable, yet still be at home carving up backroads and killing cones. The goal is to have it done for my wedding in August, but hopefully a lot sooner. But let's be honest here, we all know how that goes...

 

"Go to bed, we're getting married tomorrow!!!"

 

"Ok-ok-ok, I'm almost done, just gotta tighten a few bolts!"

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JCan    1

Sounds like you have just about everything you need to complete the car... and because of it I do not have any suggestions to add.

 

The car I am building is for my son, and because of it, I purposely didn't add a lot of horsepower.  

 

However, a 2.8L block with fuel injection and a turbocharger with waste gate set at 14-16 psi really has some get up and go.

 

I look forward to reading about your progress!

 

PS

Congratulations on your wedding!  However after I was married, I lost about 50% of what I call "peer pressure points" (having influence over your wife) so I say "get the car finished at all cost, prior to the wedding!!!"  --- GRIN

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Leon    35

Sounds like you have just about everything you need to complete the car... and because of it I do not have any suggestions to add.

 

The car I am building is for my son, and because of it, I purposely didn't add a lot of horsepower.  

 

However, a 2.8L block with fuel injection and a turbocharger with waste gate set at 14-16 psi really has some get up and go.

 

I look forward to reading about your progress!

 

PS

Congratulations on your wedding!  However after I was married, I lost about 50% of what I call "peer pressure points" (having influence over your wife) so I say "get the car finished at all cost, prior to the wedding!!!"  --- GRIN

 

Jim, I'm really liking the progress of your build as well. It's well thought out. With that said, I don't know if I'd trust my kid (whenever that happens...) with a car like that!

 

Ha! "Peer perssure points", I like that!

 

I asked her, "so can the Z be in the wedding?" She replied with a "yes", of course, she likes the car and has been very supportive of my addiction (she's the reason I got my first 240Z!). I replied with, "well then I'll just work it into the wedding budget..." :lmao:

 

She wasn't laughing...

 

I'll keep you guys updated!

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EvilC    42

Great story and very nice car, you sure know how to find them :wink:

 

 

Can't wait to see of you get this done in a few months and I sure you will be able to. I need to get filters like you have on your webers. So much to do!

 

Keep us updated!

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Leon    35

Great story and very nice car, you sure know how to find them :wink:

 

 

Can't wait to see of you get this done in a few months and I sure you will be able to. I need to get filters like you have on your webers. So much to do!

 

Keep us updated!

 

Thanks Clive! I'm actually curious about the filters, so I'll be going to the dyno when it's ready. :)

 

Hope your Z is progressing well!

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Gollum    23

For a good machine shop that's not robello, look for the machine shop that's on main street in walnut creek. I can't remember the name, but I can look them up if you can't find them. They don't have a ton of datsun experience, but they're one of the best subie porters in the world, and ironically majority of the work is actually in the diesel field.

 

All the guys there are absolutely awesome, and the owner REALLY knows his stuff and is fun to talk with. I have no doubt he won't just take good care of you and your head, but charge you fairly while doing a great job. I haven't found any other bay area shops I'd trust with a datsun head other than these guys. And remember, because they're heavy into the diesel stuff, they understand how to treat I6 heads which tend to warp differently than shorter V8 or I4 heads.

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Leon    35

For a good machine shop that's not robello, look for the machine shop that's on main street in walnut creek. I can't remember the name, but I can look them up if you can't find them. They don't have a ton of datsun experience, but they're one of the best subie porters in the world, and ironically majority of the work is actually in the diesel field.

 

All the guys there are absolutely awesome, and the owner REALLY knows his stuff and is fun to talk with. I have no doubt he won't just take good care of you and your head, but charge you fairly while doing a great job. I haven't found any other bay area shops I'd trust with a datsun head other than these guys. And remember, because they're heavy into the diesel stuff, they understand how to treat I6 heads which tend to warp differently than shorter V8 or I4 heads.

 

Sweet, thanks for the tip, Nate!

 

Safe to assume it's these guys?

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Leon    35

Now that I think about it, I can stop by Gotelli's as well, they're much closer to my neighborhood, and get some recommendations. Maybe check in with Ditos Motors to see who they use too. i know they rebuild engines and that's where I go to dyno the Z.

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Perfect240z    0

Well as long as you know what you want done, the machine shop I took my other head to is good as long as you know what you want, the price was so good.  They have limitations because of the age and how much room they have in the shop, and one of the guys used to work on Datsun's.  I was going to go to a shop over here in livermore called terry tinney performance.  They do classic race cars and seem t be really good, but the work I was outta my price at the time since I had a made a lot less back then.  http://www.terrytinney.com/

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calpoly-z    10

Leon, 

 

Ground vehicle dynamics was a very enjoyable course. Did you ever take single track design with that same prof (completely forgot his name, and but now that you mentioned it i do recall he had a datsun too). I thought single track was a better class but mostly because I actually got to build something. Loved it! I built an electric scooter. With suspension! It was bad ass. Glad you picked up his car and it stayed in the Cal Poly family. 

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Leon    35

Leon, 

 

Ground vehicle dynamics was a very enjoyable course. Did you ever take single track design with that same prof (completely forgot his name, and but now that you mentioned it i do recall he had a datsun too). I thought single track was a better class but mostly because I actually got to build something. Loved it! I built an electric scooter. With suspension! It was bad ass. Glad you picked up his car and it stayed in the Cal Poly family. 

 

Hey Alec!

 

Unfortunately, I couldn't fit in single track into my schedule at the time (prof is "Fab" BTW :)). I LOVED ground vehicle dynamics. I'm glad the Z is staying in the family as well!

 

Wish I could've build a bike, you still have the scooter? Looks like Texas is treating you well, man. I'm sure you're enjoying your house and 370Z!

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Leon    35

Ah, it was in Martinez! Thanks for the rec! This is great info for Bay Area guys.

 

I did some research yesterday, myself. Made a trip to Gotelli's (local speed shop, love that place!) to pick up some Redline for the S2000's oil change. My baby only gets "the best". :roll:

 

I BS'd around with the guys and asked for a local shop recommendation that does OHC engines. They recommended Baca's Auto Machine and "Stevie" specifically. They said Baca's does a bunch of Honda engines and pretty much anything else you can think of. It was just 10 min away in South SF so I drove down to the shop and man, it definitely looks like it's been around for 50+ years (current owner later told me the shop opened in '68)!

 

I spoke with Stevie, he's a cool guy and seems like he knows his way around this stuff. What gave me extra confidence was that he's done L-series work before and there was an L block sitting right by my feet, waiting to be worked on! I was quoted $500 for bottom end machining (that's magnaflux/cleaning, boring, crank turning, rod resizing... some of this may not be needed) and $750 for bottom end machining plus assembly. I'd love to assemble my own block, but time is of the essence here! I'll leave myself plenty of time to put the rest of the engine together and into the Z.

 

Now, the only problem is, the crank is still in SLO! I had to leave quite a few parts behind in SLO that we couldn't fit into the 4Runner, Outback, or the Z. Specifically, another block, couple cranks, couple of air dams, etc.

 

I'll keep you all updated, and hopefully this shop comes through!

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JCan    1

Leon.  You did not mention what I believe is the most important thing about the bottom end....  Balancing>[email protected]#$~!!!!!!!   How good is this shop at balancing the crank/flywheel/rods/pistons/pressure plate???  My brother and I always focused on ensuring our engines could easily wrap to 8krpm without too much vibration. (of course you know that one of the great things about the L6 is that it can be perfectly balanced at all frequencies and does not need a "harmonic balancer"),

 

Back in the day, my brothers car, L28/mild cam/webbers/11:1 compression, ran on 97 octane, and would smoke lots o cars just because we had such a wide and flat torque curve (leveraging RPM).  Each time we rebuilt it, the car seemed to be smoother and smoother.

 

I am sure you are doing this, but if not, you might forgo having the shop assemble your motor so you can spend your money having the shop balance the key components.

 

Also...  what compression are you looking for?  what head / piston combinations are you planning? 

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Leon    35

Leon.  You did not mention what I believe is the most important thing about the bottom end....  Balancing>[email protected]#$~!!!!!!!   How good is this shop at balancing the crank/flywheel/rods/pistons/pressure plate???  My brother and I always focused on ensuring our engines could easily wrap to 8krpm without too much vibration. (of course you know that one of the great things about the L6 is that it can be perfectly balanced at all frequencies and does not need a "harmonic balancer"),

 

Back in the day, my brothers car, L28/mild cam/webbers/11:1 compression, ran on 97 octane, and would smoke lots o cars just because we had such a wide and flat torque curve (leveraging RPM).  Each time we rebuilt it, the car seemed to be smoother and smoother.

 

I am sure you are doing this, but if not, you might forgo having the shop assemble your motor so you can spend your money having the shop balance the key components.

 

Also...  what compression are you looking for?  what head / piston combinations are you planning? 

 

Jim, thanks for the tips! This is actually my first full engine rebuild, so I'm starting fresh here. Balancing is a great thing to mention and something I forgot to ask about. D'oh! If they can balance the crank, ensure consistent rod and piston weights and balance the clutch/flywheel/PP, we'll be in business!

 

Compression will be CA pump gas friendly, i.e. no more than 10:1. It'll be a flat-top L28 with either the modified E31 (depending on chamber size, haven't cc'd yet) or a cut-down P90. I'm more worried about clean ports and big valves than maximizing compression.

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JCan    1

Leon.  They are not going to balance your engine unless you ask for it.   V8 engines can not be balanced throughout the rpm range and require a harmonic balancer, this pully sits on the front of the crankshaft and is offset and designed to make your engine run smooth at one RPM.  on american engines I believe the RPM is maybe 4k?  If you balance your L28 and they do a good job you will be amazed at how comfortable it is to run your engine to 7k+rpms

 

(remember HP = torque * RPM, a flat torque curve out to 5k if you can get it yields what I consider to be as close to a variable displacement engine at 2krpm=x1HP

 

The crank and flywheel assembly need to be done dynamically.  Piston and rods are done statically.  I checked the piston weights, rod weight (big side and small side) and they were accurate to 1 gram. (I have a digital cooking scale I "borrowed" from my wife when she was away :)

 

Don't be afraid to assemble the bottom end yourself. It is easy and you can check clearances with plasti-gauge and some calipers (digital ones are really inexpensive now).

 

If you want to talk, give me a call.  858 204 9422.

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JCan    1

Leon, I am afraid I am going to be a bit long winded now...  Apology in advance...

 

Attached are two screen shots of an excel spreadsheet we assembled for the car we are building.  Given torque as a function of RPM (what we expect to get out of our build) and the gear ratios w can assemble optimum shift points and can plot HP as a function of Speed (assuming I am racing the car).

 

Please take a look at the spreadsheets ---  

 

Since I know my tire diameters, rear end gear ratio, and transmission ratio, and can look up what other people have measured (torque vs rpm) I can take a look at what the optimum shift points are for my car.  The first spreadsheet shows (from right to left) RPM, Torque, HP, then left to right, the speed the car would be traveling if it were in 1st gear, 2nd gear, ... 5th gear by knowing the speed and Engine RPM then looking up the available HP (in the right).

 

First thing, notice the knee in torque at 5500 RPM (I expect the engine I am building will not knee until 6000 rpm, but I am being conservative here).  The loss in Torque causes a loss in horsepower at 6000 RPM.  A wider torque curve would greatly improve overall HP.

 

Your car has webbers ( a 6 pack right? )  Well your torque curve comes up much faster in the low end then mine does using SU carbs.  You can model this here also.!

 

Lastly, lets take a look at the last plot.  In this plot I plotted the available HP as a function of RPM  you can see the HP dips / each represents a shift point.  In addition, I compared the car as is with a different rear end (one with 4.11:1 gear ratio).  Notice the low end HP improvement!

 

What happens if I swap out the stock rear end for one which has 4:11 gears.   Notice we get 160HP at the tires at 20MPH in first gear (4:11 gears) instead of 35MPH at first gear (3.5:1).  This little change should make a BIG difference to quarter mile and off the line times.  Again, note your webbers have more torque at the low end then my SUs so your results may be difference. Which means, if I want my car go go faster, the easiest thing to do is to change gear ratios instead of farting around with trying to eek out another 5HP.

 

This is a long winded way to say:

 

            - The L24/26/28 are magic motors and one thing they have is their ability to be perfectly balanced throughout all RPM.  Take advantage of it! 

                     o balance your motor

                     o understand how your modifications will effect torque

            - Take top down approach to building your car and understand how your car will respond to each modification you make

                     o sometimes your best modification are gear ratios

 

If you want a copy of my spreadsheet, send me an email and I'll forward it to you.  [email protected]

 

 

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post-29130-0-52638900-1359839564_thumb.jpg

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Leon    35

Wow, Jim! I really appreciate your long response and for sharing all your work. Looks like you have a great plan for your build!

 

I also have a quite involved spreadsheet with dyno plots, gear ratios and tractive effort curves, letting me get the most out of the engine and gears. All of that is thanks to the previous owner, who was my Vehicle Dynamics prof!

 

The tractive effort curves show me the optimal shift points, based on the force available at the wheels. The "perfect" shift is when your tractive effort matches with the gear you're upshifting to.

 

Luckily enough, these engines are internally balanced and resilient to 1st, 2nd, and 3rd order harmonics. Gotta love straight-sixes! As you've implied, the crank and clutch will be balanced individually, and the pistons and rods will be weighed to make sure they match each other. Looking forward to seeing you work and meeting sometime!

Thanks again, Jim. ;)

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JCan    1

Vehicle dynamics prof?  Leon, you are a sleeper!  Send me your spreadsheet, maybe I could learn from it!  Also, if you have a good book on vehicle dynamics  I would appreciate the name as I might be able to thumb through it and get a better understanding of automobile engines etc.  ( I did measure in general engineering in college and took the basic engineering courses, thermo, statics and strengths of materials etc).

 

In the mean time, tractive effort curves...  I'll look them up!

 

My spreadsheets are rudimentary as I made them up in an effort to ensure the car I am building does NOT have tremendous HP from 0-60 (as after all I am handing it to my 16 year old son) yet allows me to add a few tweaks once he gets older to increase the fun factor!  (notice the gear ratios are really high, I used SU carbs, the cam is a mild cam which destroys low end torque - yes the bad side is that after the engine hits 35mph, the car should be a rocket however brian's primary driving will be below 50 mpg (mostly streets).  

 

 

Jim 

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Leon    35

Vehicle dynamics prof?  Leon, you are a sleeper!  Send me your spreadsheet, maybe I could learn from it!  Also, if you have a good book on vehicle dynamics  I would appreciate the name as I might be able to thumb through it and get a better understanding of automobile engines etc.  ( I did measure in general engineering in college and took the basic engineering courses, thermo, statics and strengths of materials etc).

 

In the mean time, tractive effort curves...  I'll look them up!

 

My spreadsheets are rudimentary as I made them up in an effort to ensure the car I am building does NOT have tremendous HP from 0-60 (as after all I am handing it to my 16 year old son) yet allows me to add a few tweaks once he gets older to increase the fun factor!  (notice the gear ratios are really high, I used SU carbs, the cam is a mild cam which destroys low end torque - yes the bad side is that after the engine hits 35mph, the car should be a rocket however brian's primary driving will be below 50 mpg (mostly streets).  

 

 

Jim 

 

I'll PM it to you. ;)

 

Race Car Vehicle Dynamics (Milliken and Milliken) is the chassis bible and Internal Combustion Engine Fundamentals (Heywood) is the engine bible as far as I'm concerned. Both are fantastic books.

 

I hope your son drives the Z responsibly, you're putting a lot of thought and work into this. I like your design intent!

 

Here's a good example of a tractive effort curve:

 

trans%20Gear%20Tractive%20Force.gif

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JCan    1

Interesting topic.  Ive been reading about tractive effort and tractive resistance at:  http://www.thecartech.com/subjects/auto_eng/Tractive%20Effort.htm  .  It is going to take me a couple days to absorb what I am reading.  Basically we are optimizing the amount of Force (N) applied to the wheels and picking the optimum gear ratios to deliver this force on a level road taking into account rolling resistance  air friction, and effective wheel diameter (rubber tires are lossy as compared to steel wheels).  

 

You know, I have always thought of the 240z as a variable displacement engine.  IT seems to me that one could design an optimum gear ratios for fuel economy AND also take account the cars max performance.  Therefore we could have one set of curves with the optimum RPM being low (2500 rpm) optimizing for economy and a traditional set of curves with higher RPM say 6000 RPM optimizing Force applied to the wheels, (tractive effort)

 

Regarding Brian (my son).  I think he has a level head and is rather deliberate with his actions.  As he has completely reassembled each part of the car (with help from me of course) he has a lot of pride in it and doesn't want to damage it.  Brian will only drive the car for the next two years, as when he goes away to college, the car will stay here (we do not allow our children automobiles at college).  Once he graduates, I will put the car in his name and he will be free to upgrade it as he sees fit...

 

Thanks for the introduction to great resources (Books) and this topic of Tractive effort.  I am sure (over the next couple of months) to add this newfound information to my understanding of the car.

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