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ScienceofSpeed Expands Engine Offerings with NSX 3.5L Short Block Program

19 January 2001
Chandler, AZ
<img border="0" alt="" src="http://scienceofspeed.com/products/engine_performance_products/NSX/ScienceofSpeed/3.5L_Short_Block/3.5Lshortblock_450.jpg" align="right">ScienceofSpeed is expanding its engine program for the NSX with the addition of the 3.5L NSX short block program.

for more information:

We've been fortunate to have gained extensive experience with the NSX engine with 54 NSX engines complete or in process to date. Several years ago, we introduced our 3.5L stroker kit which includes a billet machined 4340 alloy steel crankshaft, connecting rods, and 2618 forged aluminum alloy pistons. The kit utilizes a 93mm bore x 86mm stroke for a total displacement of 3.5L. The package is made possible with an advanced crankshaft design with enlarged main and connecting rod pins to support the increased power of these engines. Cross-drilled oiling pattern with increased bore and chamfered oiling holes increase connecting rod lubrication supply. The factory cylinder block is align bored and honed to accept the larger main pins during processing. The rotating assembly fits into the confines of the factory cylinder block with no additional machining or grinding required.

The engine short block assembly is nearly identical between naturally aspirated and forced induction engines. The naturally aspirated engine uses lightweight tapered H beam connecting rods while the forced induction application uses a heavy duty H beam connecting rod with 3/8" CARR bolts.

The larger displacement 3.5L engine with a 93mm bore and 86mm stroke greatly increases power throughout the RPM band with much greater torque at lower engine speeds for both naturally aspirated and forced induction applications. Natural aspiration 3.5L engines are capable of up to 450 horsepower at the engine with suitable induction and cylinder head modification and forced 3.5L induction engines are capable of in excess of 700 horsepower at the engine with suitable forced induction system.

Previously, we have required customers to send the entire NSX to ScienceofSpeed for the 3.5L engine so that we could verify quality of installation during every step of the assembly, installation, and tuning processes. Based on popular demand, we've developed a more flexible progream specifically targeted to customers where sending the vehicle to ScienceofSpeed is not feasible (such as international customers).

The ScienceofSpeed 3.5L Short Block Engine Program provides the customer with a blueprint assembled engine ready for cylinder heads and accessories.

The core short block program provides a pre-assembled cylinder block that has all wear surfaces replaced or machined for like-new condition. The assembly includes the complete rotating assembly, bearings, and factory seals. Each specification (oil clearances, piston - cylinder wall clearance, mass of rotating components, etc.) is documented during the blueprinted assembly and provided with the assembled short block. The short block is ready for assembly with customer prepared cylinder heads.

3.5L NSX Assembled Short Block Includes:
  • disassembly, cleaning, and inspection of core cylinder block
  • align bore & hone main journals
  • resleeve, bore & hone w/ deck plate
  • pressure check cylinder block
  • surface cylinder block decks
  • ScienceofSpeed Billet 4340 Crankshaft
  • ScienceofSpeed Billet 4340 Connecting Rod Set
  • ScienceofSpeed Forged Aluminum Piston Set
  • Mahle Clevite TriArmor Racing Main & Rod Bearing Sets
  • genuine Honda thrust washers
  • dynamic balanced rotating assembly
  • complete cylinder block gasket set
  • documented blueprinted assembly including specification sheet

for more information:

-- Chris



"enlarged main and con rod pins"

Can you elaborate a bit on this? I'm not following.

For NA applications, are you recommending a reduced redline for these engines because of the heavier rods?

Looks very nice! Thanks for your work!
"enlarged main and con rod pins"

Can you elaborate a bit on this? I'm not following.

For NA applications, are you recommending a reduced redline for these engines because of the heavier rods?

Looks very nice! Thanks for your work!

The main pin is increased in diameter by 5.2% and the rod pin is increased 1.5%. This increases shear strength of the pins, increases oil film surface area, and on the mains, allows us to bore new main journals bringing the block to new on all wear surfaces. In general, for racing applications we leave the rev limiter at factory point to give the driver some additional room to carry through a corner with out having to shift. For long term durability for street applications, we decrease the rev limiter by 5-10% depending on the application.

-- Chris
Chris- So you have probably come to the conclusion that the stock rods are not strong enough for the stroker? What compression ratio are you setting these up for for NA? Thanks for the data.
No, the stock rods are perfectly adequate for NA use (as we have used them in quite a few prior builds using a different piston / crankshaft design).

The use of a custom rod gives three advantages: 1. rod length we desire with the piston design we prefer 2. gives us a solution for high horsepower FI engines 3. doesn't require us to rely on used connecting rods. The factory rod is nice, but is not that light compared to the tapered H beam connecting rod we use. Our piston & rod combination (1003 grams - from a high compression build) is lighter than the factory piston & rod combination (1145 grams).

Compression ratio can vary from factory to ~ 13.2:1. For street applications using premium fuel, we will use up to 11.5:1. On E85 or racing applictions using 100+ octane (R+M)/2 we have used 12.5:1.

-- Chris