Dear Oppo, My dreams....

"GhostZ" (GhostZ) 10/12/2013 at 01:04 • Filed to: None

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Straight six. 5" bore. 2.5" stroke. 300 cubic inches. DOHC, tall port intake. 9" Deck height. 1.3" compression height. 6.45" inch connecting rod. (making a 2.58:1 stroke/rod ratio) 8.2:1 Compression with dished pistons. Twincharged on a small turbo on a clutch-activated supercharger.

Mean piston speed of 4250 (about what modern production tolerances are) occurs at 10,000, which would be set as the injector's redline. Higher quality parts might pull it higher.

Under 5000rpm, the turbo would provide a small boost in power allowing the high-duration cam to still operate efficiently, and overcome some pumping losses. Boost is small, and mapped out mostly for mid-throttle, optimized for economy ecoboost-style. Peak power at 5000rpm would be about 300, with about 310ish ft/lbs.

At over 5000rpm, the supercharger would clutch-in and providing 10-12 lbs of boost (at the cylinder, including pumping losses, so closer to 15psi output) blowing through individual throttle bodies.

Length-tuned exhaust runners, side-pipe exit.

Peak power: 300 ci /4.9liters @ 12psi @9000rpm = about 950HP and 525 ft/lbs

Install it in a RWD car, Treme TKO600 manual with a lightweight, carved-by-me-for-me pistol grip shifter, fully independent suspension, on 285/35ZR18 MIcheline Pilot Supersport tires (...or maybe Mickey Thompsons. I haven't decided yet) with great downforce and weighing around 3000lbs with a 55/45 weight distribution, and a (gentle) LSD.

The gearing should be good to spin up the 9000rpm up to 250mph (if the car can keep accelerating, that is, which it probably couldn't, but hey, 200mph is good enough).

4-wheel disc brakes with drilled and slotted ceramic rotors.

Chassis stitch-welded and carefully stripped and prepared to handle the stress of the engine.

Wrapped up in this:

This is my dream. There are many like it, but this one is mine.

MR2_FTW - Group J's resident Stig > GhostZ 10/12/2013 at 01:07

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Awesome, but two issues:

1. You'd want the SC for low RPM's and the turbo for high RPM's

2. Drilled rotors are teh suck. Slotted is fine, but drilled rotors exist solely for the "bling" factor, and tend to crack under actual high-stress driving.

BJohnson11 > GhostZ 10/12/2013 at 01:12

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O.O 5" bore? Jeezus. Has that been done on an inline 6 (I don't know much about them)? From working at an engine machine shop though, I can honestly say the only 5" bore I remember seeing was out of a 600 something cubic inch V8 some guy was running in his Bonneville speed record car. AND THAT BORE WAS HUGE!!!!!!!!!!!!!

My 454 has a 4" bore and even thats pretty big. But hot damn the rest of that build sounds like sex. I've always loved the idea of twin charging, and I would love to try it some day.

GhostZ > MR2_FTW - Group J's resident Stig 10/12/2013 at 01:12

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I thought the advantage of drilled rotors was to allow both air circulation and hot brake dust to be expelled faster than just slotted rotors do? I never thought of them as much of a 'bling' upgrade.

While the SC for low RPMs is generally better for power, the idea is to not use the turbo at all for power and just use it to improve MPG below 5000rpm, and let the track driving (on a supercharger) suck gas over that amount. The Low SC High Turbo setup is usually good so you can get quick-response low-end torque without sacrificing top end, but in this case, if you're going below 5000rpm in track driving, you're probably driving this engine (theoretically) wrong.

DrJohannVegas > GhostZ 10/12/2013 at 01:12

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No L-series will handle a 5-inch bore. Sorry.

-The Doctor.

Cherry_man1 > GhostZ 10/12/2013 at 01:15

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Good god.......um, um um can I call it the Red Devil Z?

GhostZ > BJohnson11 10/12/2013 at 01:16

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5" bore engines are common in top fuel, funny car, and superstock drag racer engines and the pistons are available for it. Anything over that gets pretty damn custom.

It's not common on an I6 because of the length. An I6 is about 1/3rd longer than a V8, so if a 4.4" bore spaced block (a small block V8) fits somewhat snug but comfortably.... imagine adding 3.5 inches in bore spacing, and 10 inches in two more more cylinders. You'd have to stuff that thing deep into the firewall to make it fit.

GhostZ > DrJohannVegas 10/12/2013 at 01:18

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No way in hell I'd be using an L engine. I love those things, but single-cam and non-crossflow makes me sad, plus the cooling issues at higher HP levels.

GhostZ > Cherry_man1 10/12/2013 at 01:18

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Updated the picture. I want it in white.

BJohnson11 > GhostZ 10/12/2013 at 01:19

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Right. So full blown (read; $30,000+) race engines have 5" bores, so it is possible. Optimistic, but fun sounding project!

Cherry_man1 > GhostZ 10/12/2013 at 01:20

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SHIKAKA!

MtrRider Just Wants Doritos > GhostZ 10/12/2013 at 01:20

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GhostZ > BJohnson11 10/12/2013 at 01:21

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Yeah, anyone have an extra $80,000 lying around that I could dump into it?

GhostZ > Cherry_man1 10/12/2013 at 01:22

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I love that movie. Thank you for reminding me of it.

Cherry_man1 > GhostZ 10/12/2013 at 01:26

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Must be either a bumper sticker or a license plate please!

GhostZ > Cherry_man1 10/12/2013 at 01:28

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"GhostZ" would be the preferred license plate. Leave the Devils for the original red 280zx and the blue 240z. I'd go for "Ghost", or (if I wanted to be really cheesy) "Death Spirit" in Kanji.

6cyl > GhostZ 10/12/2013 at 02:07

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Under square inline 6. I like this.

Wouldn't it be better to have to turbo provide boost on the top end and the supercharger on the low end? (I don't know much about FI so I am probably wrong about this)

My dream: under square 3L inline 6, that can rev to 10k, and produce around 350 naturally aspirated wheel horse power on 93 pump gas and can be daily driven. I am nearly certain it is possible but lack the funds to do it. and I would like it in one of these:

or a z4 m-coupe I'm not picky :)

GhostZ > 6cyl 10/12/2013 at 02:14

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Way undersquare. I don't know if anyone's even made an I6 with over 4" bore spacing, much less over 5". It would have to be around 15 inches longer than the stock L24, I imagine, and that's not a small engine by any means (weighs almost 500lbs!).

For peak performance, yeah. Usually these setups have the supercharger all the time, and then the turbo blow through the supercharger when needed. But on a motor that gets most of its power over 6000/7000 rpm, "low end torque" doesn't really mean much.

My idea is to use the turbo to map out the EFI so at low and mid-throttle, you're getting highly efficient VE's at a sacrifice of full-throttle power below 5000rpm, ecoboost style so you get a small boost in peak power but a good gain in real-life MPG. Then, the supercharger takes over the actual 'hard driving' duties when you pull it over 5000rpm, since you won't be dropping below 5000rpm during track driving.

6cyl > GhostZ 10/12/2013 at 02:27

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You can get a square GMC inline six in a 302ci 4in x 4in (bore x stroke). They also produced a 503ci inline six back in the 1950's. That might be a good block to build off of.

GhostZ > 6cyl 10/12/2013 at 02:39

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The Chevy 503 still only had a 4.5" bore, but that still marks it as the biggest-bore straight 6 I've ever seen. Now you just need a custom crank to bring the stroke down.

If I were to seriously pursue this, I would start with a 240ci ford engine (the indestructible one) with a 4" bore and shorter crank, and go for more turbo pressure and adopt DOHC aussie heads onto it.

...or just get an RB26. Whatever. That's not as fun.

6cyl > GhostZ 10/12/2013 at 02:52

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I'd say start with the GMC because it is the closest bore and being that old probably has more room to the bored and sleeved. Then custom: crank, rods, head, cams, intake, headers....

GhostZ > 6cyl 10/12/2013 at 02:54

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You might have to find alternate ways of keeping the block cool too. I doubt that that old block had adequate cooling lines for the radiator, but you might be able to do some sort of double radiator setup or something.

GhostZ > 6cyl 10/12/2013 at 05:37

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Also, I didn't see your original edit, but it sounds to me like you crave a short-stroke (and stock for the Z3 coupe) S54 engine with some modern rev-inducing touches, trading stroke for RPM but keeping the stock output, but I'm sure you've thought of this already.

FalconHoon > GhostZ 10/12/2013 at 07:33

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I too dream of old inline-6 sports cars

N51fanatic > GhostZ 10/12/2013 at 08:08

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can i just say that i really want a 240z as a weekend toy? That petrolicious vid this week put me over the top. The worst part is, I have the money to make this happen today.

GhostZ > N51fanatic 10/12/2013 at 08:44

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That's the biggest problem with them. No matter how desirable they seem to get, they built so many of them that the prices won't go up to convince you against buying one.

I still think they're the best, cheapest, and most-smiles-for-dollar modification and restoration platform on the market right now.

Really, they're extremely reliable, good MPG, somewhat fast (comparable to a BRZ) excellent handling machines. You could daily drive one if you were a careful driver, they're that simple.

N51fanatic > GhostZ 10/12/2013 at 09:08

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I agree with you. My other problem is that, I have a kid on the way, and only a single car garage. Although we are financially secure and I could make this happen no problem, wife wouldnt be happy with a blue tarped Z in the double driveway :(. The other problem is I want to start midding my 1 series. Wheels, coils, tires this spring. Adding another small coupe to the fleet, probably isnt a good idea. I don't know lol.

JayZAyEighty thinks C4+3=C7 > GhostZ 10/12/2013 at 11:00

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That would be incredible to own that kind of S30. The best S30 I found has a 3.2L bored and stroked L engine and revs past where most tachs will go.

Mine would be a Supra with a 3.4L stroked 2JZ with bigger sequential turbos for responsiveness, new piping, and better internals for 9000RPM. Carbon fiber body to save weight, chassis stiffening, and new suspension would follow. It wouldn't be bad on the road, while being great on almost any large, fast tracks.

6cyl > GhostZ 10/12/2013 at 11:33

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Yeah basically an s54 with a lightened internals, stock compression ratio to reduce the chance of knock, probably some head reworking, lumpy cams, big valves, dry sump, custom exhaust, intake with staged injection, a dual plenum on the end of the velocity stacks for even airflow. I think 400 wheel would be pretty hard to achieve. Even 350 might be tough. Getting more NA power out of an already really well designed motor is a pretty tricky.

GhostZ > JayZAyEighty thinks C4+3=C7 10/12/2013 at 17:27

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I wonder if that engine has a DOHC conversion... most stroked L engines won't break the 9000rpm limit without some kind of improvement to the head/cam design, the pumping losses get too high. But way back in the day, supposedly Nissan (via Bob Sharp racing) had some turbo DOHC L engines in the 280zx that were making 600-700HP at over 11000 rpm in the early 80s. The engines wouldn't last very long, but it really gives testament to the strength of the design. They were still one of the most balanced and reliable I6s ever built I think.

JayZAyEighty thinks C4+3=C7 > GhostZ 10/14/2013 at 14:37

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Agreed; 9000RPM is an incredible figure for an engine of that era. I'll see if I can find some footage of the 11000 RPM cars. I would love to have an S30 if only for the engine, but everything about them (bar rust) is drool-worthy. You might like the new Petrolicious video if you haven't seen it.

Just remembered what the Bob Sharp cars were like. Reminds me of an embarrassing moment: I'm probably around 10 years old, and I say hi to someone in an elevator. He tells me he's a retired racer and he's going to drive a friend's car. When I ask him what it is, he pulls out his phone and shows me a small picture, asking what it is. At this point, I nervously blurt out 911 (remembering a 935 livery), to which he replies it's a 300ZX. The next day I watched a video about the V8 Z31s raced by Paul Newman, and feel really stupid.