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Project Silvia S14 block S13 head long-rod SR20DET

Project S13 Silvia

Taking 2 Pounds off the Bouncy Bits!

by Dave Coleman 

The last installment of Project Silvia was a story of tragedy. A tempting, but ultimately unnecessary attempt to broaden my powerband, coupled with a string of bad luck, and my own staggeringly shortsighted outdoor storage strategy had reduced my stone-reliable SR20DET into a worthless, rusty mess.

Project Silvia is a rusty tale of tears
This is what your cylinder walls look like if your idea of block prep is WD40, duct tape, and a year of neglectful indifference.

So at the end of the last installment, I changed my strategy. Instead of a simple S13-to-S14 head swap, this was now a full balls-to-the wall rebuild to get the most output from this engine I possibly could. The most, with three very important caveats. 

When I built Project Silvia the first time, there was an opportunity to install a race gas map. Clark Steppler, the Nissan ECU mastermind at Jim Wolf Technology, had rigged up a way to switch between 4 different fuel and timing maps on a stock Nissan ECU. We could easily have tuned one map for the recently-introduced 91-octane distilled bum sweat we run our cars on in California, and another for 100-octane unleaded. But I was never even tempted by this idea. The thought of paying for a full tank of $5/gallon race gas was just too outrageous!

A few months ago, 87 octane was $5/gallon (its dropped nearly a dollar since then), so it should come as no surprise that race gas is still off the menu. So that's caveat #1: This engine will be built around a diet of 91 octane. That means we'll be doing everything possible to keep this thing from knocking, and we'll be looking for power in places that don't require higher cylinder pressures--like friction reduction.

#2 is simple. I am a mammal, and as such, I'm smart enough not to shit on my own dinner plate, or to poison my own air. Well, at least not any more than is absolutely necessary to keep myself entertained. So this engine will breathe through a cat.

And finally, #3 is is that we must define "the most" very carefully. Getting the most out of this engine does not mean making the biggest peak power number. It means a big, wide, useable powerband. If peak power must be sacrificed to improve responsiveness and torque, I just might do it. The crude VVT system on the S14 head should make that unnecessary, though.

Dave Coleman machines a Miata engine with a file... Like a BOSS
This is me, actually machining a Miata cylinder head with a file. This is why.

Ok, so now that we all understand the goals, how the hell am I going to pull it off? Every time I touch this engine, I'm overcome by an urge to machine it with a file, or weld some Mexican Dodge parts to it. My instincts are so thoroughly ghetto, I'm not sure I can trust myself to go full Kojima on this thing. So I've assembled a team of detail-obsessed nerds to look over my shoulder and slap my hand every time I reach for the zip ties.

Clark Steppler has been my go-to Nissan nerd for years. I always turn to Clark first for advice on nonsense like this, and one of his first pieces of advice on this engine surprised me. "Don't assemble it yourself." The thought of not building it myself never even crossed my mind. I always build my own engines (for better or worse), but perhaps Clark knows me better than I know myself. Instead, he suggested I turn to Nick Hunter at 5523 Motorsports to screw it together. My initial hesitation evaporated as he started telling me about Nick's attention to detail, including strange little tricks like how he hand cuts oiling grooves in the main bearing support to bring SR20s up to the same spec as the rare Pulsar GTi-R engines. My engine could use a bit of that obsessive attention to detail, and it sure isn't gonna get it from me!

Nick is also the guy who heroically built a backup VQ35DETT for Dai Yoshihara's drift car on only 3 days notice, in his living room, when the original engine blew a head gasket during demo runs in Abu Dhabi and had to be running again a few weeks later in Qatar. Yeah, Ok, I like this guy... Mine will be one of the first batch of engines built in 5523 Motorsports' fancy new clean room, so we won't have to worry about getting silver engine paint on his La-Z-Boy.

The third member of my ghettocharging recovery support group is MotoIQ's own Chuck Johnson. Chuck's day job at JE Pistons focuses his nerdly obsession at the bouncy bits, and that's where this project finally gets going. Parts catalogs are an engineer's best friend, and it was reading his favorite parts catalogs a few years ago that Chuck figured out the Honda H22 long-rod trick that has spread through the MotoIQ garages like a virus.

Squeezing a longer connecting rod into an engine is a relatively common trick for extending the rev range of an engine. The benefits of longer connecting rods are simple, if a little tricky to grasp at first blush. There are several things going on when you change the length of the connecting rod. Most of them are subtle, and some of them are good. 

 

Project Silvia S14 block S13 head long-rod SR20DET

Less friction: Look at this diagram of a reciprocating group with the crank at 90 degrees. When there's some force pushing down on the piston, the angle of the connecting rod ensures there will be a reaction force shoving the piston into the cylinder wall. A longer connecting rod will result in a slightly shallower connecting rod angle. Shallower angle means less side load, which means less piston to wall friction.

 

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Comments
Dan DeRosia
Dan DeRosialink
Tuesday, February 19, 2013 3:18 AM
I know this is a question that carries a lot of baggage, but what's the provenance of the K1 stuff? I ask because I'm looking at one of their Subaru cranks for a project - I've heard of known folks in the Subaru community using their bits but it's been in my mind.

Cool details on the pistons; I'd heard of people putting the oil rings past the pins, but not in street use.
8695Beaters
8695Beaterslink
Tuesday, February 19, 2013 5:15 AM
About damn time we saw some updates on this car! It's been a year and a half since we heard about this car.

I'm very interested to see how the rod bearings come out. Know of any East Coast shops that do the same kind of mods to bring the rod bearings to GTi-R spec? Also, what kind of bearings are you using for this engine? I've got an SR20 to build for my own car and I'm very keen to see the results of this one, since mine will be pretty similar (or possibly completely identical since I have similar goals, though with the luxury of 93 octane coming out of my pumps).
Cody
Codylink
Tuesday, February 19, 2013 5:30 AM
New catch phrase? Go full Kojima!
Bowie
Bowielink
Tuesday, February 19, 2013 6:38 AM
@8695Beaters,

I'm believe Mazworx in Florida offers a similar rod bearing modification.
Rockwood
Rockwoodlink
Tuesday, February 19, 2013 6:55 AM
@ 8695 Beaters: You can also freight things for not a huge amount of money these days if you're willing to pick up and drop off from a distribution center.

@ Dave: you spell "ketchup" funny... ;-p
theneil
theneillink
Tuesday, February 19, 2013 10:06 AM
Dave im glad your back, I originally found motoiq by googling your name. Hows the miatabusa?
Dave Coleman
Dave Colemanlink
Tuesday, February 19, 2013 10:35 AM
@ Rockwood,

You're right, I did spell ketchup funny. I was using my own twisted version of the southern alternative spelling catsup, which must have been logged in my brain from too much time in Kentucky. I didn't even spell it right in the southern form, though. Oh well, thanks for keeping my condiments honest.

@ theneil,

Parts are slowly being made to right the mistakes of Miatabusa 1.0. Landscaping and interior decorating, strangely, are slowing things down...
Dusty Duster
Dusty Dusterlink
Tuesday, February 19, 2013 11:21 AM
LOL, "Go Full Kojima."
Rockwood
Rockwoodlink
Tuesday, February 19, 2013 12:43 PM
@ Dave: southern words have no proper spelling. Go to any "lifted truck hee-haw" forum and you'll see.

@ Dusty: You went full Kojima. Never go full Kojima. You don't buy that? Ask Ryan Besterwich, 2001, Remember? Went full Kojima, still never started his car.
GCMBob
GCMBoblink
Tuesday, February 19, 2013 4:51 PM
LOL ^

Everytime i read these posts it make me want to have an engine built. Then i remember there is no point here...cry
spdracerut
spdracerutlink
Tuesday, February 19, 2013 6:55 PM
man.... 2 lbs is a ton off of the rotating assembly. Should rev really nice!
2cute
2cutelink
Tuesday, February 19, 2013 7:03 PM
@ Dave - correction. That VQ for Dai was out together in the kitchen. Not the living room. Lol.
2cute
2cutelink
Tuesday, February 19, 2013 7:05 PM
That should read put together not out together. Stupid apple products.
rawkus
rawkuslink
Wednesday, February 20, 2013 4:42 AM
What does 2 lbs of rotating mass removed translate to? As in, what is the primary benefit? Reducing the loads on bearings and cylinder walls make the most sense to me, but how much is power/efficiency/fuel economy/ect... is improved? Awesome article!
Dan DeRosia
Dan DeRosialink
Wednesday, February 20, 2013 5:44 AM
In terms of flat out power, it alone isn't going to do much aside from a bit less friction, but there's a lot less stress on the rods and bearings, so it enables everything to be run at higher speeds safely. Response is another issue; it's that much less mass that's moving around, ala lightweight flywheels.
Protodad
Protodadlink
Wednesday, February 20, 2013 8:45 AM
@Rockwood "@ Dusty: You went full Kojima. Never go full Kojima. You don't buy that? Ask Ryan Besterwich, 2001, Remember? Went full Kojima, still never started his car."

Thank you for this, I couldn't remember the full quote but its all I thought of when i read "full Kojima"
OMG Its Weasel
OMG Its Weasellink
Wednesday, February 20, 2013 10:30 PM
Those US Magnum scales sure do get around. Is that the harbor freight one?

make sure you calibrate it a lot. mine goes out of calibration almost everytime i use it.
kingisher59
kingisher59link
Wednesday, February 20, 2013 10:53 PM
Is there any way to get your old write-ups on Project Silvia?

I'd say 90% of my SCC mags have found their way to the trash (not by me), and the search on the Modified website is atrocious.
Mrad
Mradlink
Thursday, February 21, 2013 3:38 AM
So glad to see an article form Dave again, I've had too much going full Kojima.
jeffball610
jeffball610link
Monday, October 21, 2013 11:36 AM
It's been over 9 months since this article came out. Any updates on Project Silvia? I know Dave has been busy building his shack, but I'd like to see where this project is going. I've been following it since the SCC days :)
theneil
theneillink
Thursday, December 24, 2015 7:55 PM
Dave we need to know more!!
theneil
theneillink
Sunday, July 31, 2016 12:30 PM
Is the full race efr installed photos for the sr20det actually this car? It looks like it
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