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Project NSX: Part 3 - Building a Race Proven C32 Engine

By Billy Johnson and Sarah Forst

 

At MotoIQ we have always contended that it is a much larger challenge to build an engine to hold up to the stress of road racing than nearly any other motorsports. For road racing or time attack an engine has to live despite being pounded on for many minutes at a time. A typical track session is 20 to 30 minutes long, way longer than a quarter mile or freeway blast. The continual stress of track driving is an acid test for an engine's reliability, coolant and oil temps soar and the engine is run near redline for many seconds at a time.

 
 
The C32 has a lightweight alloy block with an open deck.  The open deck gives good cylinder and head cooling and even heating of the top of the bore and combustion chamber for good emissions.  Free standing cylinders also are easy to machine precisely and do not distort when the heads are bolted on. However, for high powered turbo applications the free standing cylinders flex compromising head gasket sealing.  Under heavy loads the cylinder walls can even fail.
 

A high powered road racing engine cannot be slapped together using cheap Chinese knock off parts bought on Ebay. The attention to detail required to be reliable in this environment is intensive. In our case we will be taking on one of the biggest challenges for the tuner, building a track reliable turbocharged engine out of an engine that was not designed by the factory to be turbocharged. In this case, every bit of the engine must be scrutinized for suitability.

 
The C32 has a strong bottom end with main caps secured by 6 bolts each.  The block has deep skirts and double registers with large contact areas and cross bolting for stiffness. However when you more than double the stock power, the bores can distort causing bearing and crank problems
.
In this photo you can see the dual registers for the main caps and the holes for the ridged cross bolting.
 

Project NSX is the Brainchild of FX Motorsports Development, an NSX tuning shop whose time attack turbo NSX is currently smashing unlimited class records throughout the Redline Circuit. FX Motosports Development is transferring a lot of the knowledge gleaned from their time attack program to build the ultimate NSX turbo street motor. 

 

The goals of our motor is to make a rock reliable 500 to 550 wheel hp on 91 octane pump gas with the ability to be track driven without missing a beat.  Basically this engine is the same powerplant that propels Billy Johnson's FX Motorsports Development NSX Time Attack car to over 750 whp on race gas. For our project car, big power numbers are just a turn of the boost control knob and a tank of race gas away.

 

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Comments
Fuji-Kun
Fuji-Kunlink
Friday, October 30, 2009 4:14 PM
i love you guys. i really miss having these tech articles in print. 3 stories about engine work in one page. and it is not hard to read at all. it just flows. i love this site and i love you guys and girls. thanks you again motoiq!!!
saturn racer
saturn racerlink
Saturday, October 31, 2009 4:54 AM
Why no additional displacement? That'd also help spool the turbo for better response.
Jerk Face
Jerk Facelink
Monday, November 02, 2009 3:38 AM
Totally agree with Fuji-Kun. This kind of fantastic automotive writing is something I've really been missing!
Mike Kojima
Mike Kojimalink
Monday, November 02, 2009 5:04 AM
This engine is built for durability, so no long stroke, too high piston speed, thick cylinder walls for support, cooling and ring seal so no big bore.

This bottom end runs at over 750 hp for 20-30 minutes at a time flat out in Time Attack. Not 10 seconds down the quarter or 30 seconds to a minute in a freeway blast.
JDMized
JDMizedlink
Wednesday, November 04, 2009 1:56 PM
Excellent post (as usual).
But I am surprised you guys still run a wet sump ! If reliability is a key factor (which it is), dry sump should ring a bell. Any reason why you guys haven't considered that?
Dry sump are expensive to piece together, but considering the fact that the FX MD is dominating the Redline Time Attack series, it's a no brainer to me.
I'm curious to know why you guys haven't opted for one.
Any thought?
Thanks again for the excellent articles.
Mike Kojima
Mike Kojimalink
Wednesday, November 04, 2009 3:57 PM
The engine on the time attack car uses a semi dry sump. Two engine driven pumps scavenge the pan which feeds to a tank, de aerator. A modified stock pump then feeds the engine.

This packages easier in the NSX.

For this street car, the modded pan will be used with an accsump.
BillyJ
BillyJlink
Friday, November 06, 2009 4:29 PM
Saturn Racer: The block was originally a 3.0L C30A which was punched out to 93mm bore which equates to 3.2L (same displacement as the C32B). Increasing the bore further can increase displacement but there isn't much room to keep a sufficient wall thickness of the sleeve.

Piston speeds start to go through the roof as well as the thrust against the cylinder walls with a stroker kit. The stock 78mm stroke combined with our turbo sizing on the FX750 racecar results in an already broad powerband.

Stay tuned for future articles where turbo sizing for our power levels will be covered that will ensure a very responsive setup.

Billy
M-P
M-Plink
Monday, November 16, 2009 11:58 AM
Reading these articles about the project NSX makes me wish I could go back in time a few years and save the money I spent making my FD RX-7 my track car so that I could have put it into my NSX instead. I'm looking forward to the rest of the NSX build...thanks for the good read.
DaGou
DaGoulink
Monday, December 05, 2011 4:33 PM
anybody know why this project died?
BillyJ
BillyJlink
Saturday, March 10, 2012 8:39 AM
DaGou: it will be up and running again soon with a rebuild of the head and longblock assembly.
koko_head
koko_headlink
Wednesday, October 10, 2012 2:39 PM
Did you guys WPC treat the valvetrain? I spoke with Izumi (WPC) and he suggested the cams, cam caps, rocker arms, rocker shafts, valve stems, and retainers.

I spoke with Web cams (who is doing a hard-weld on my cams), and they said that cams, valve stems, and retainers were not necessary.

I am on a limited budget (I know, budget and NSX don't mix) so I'd like to hear your thoughts on which top end pieces would most benefit from the WPC process.

Thanks.
Mike Kojima
Mike Kojimalink
Wednesday, October 10, 2012 4:31 PM
Yes we did. Doing the valvetrain is one of the best places to do WPC.
Colorado S14
Colorado S14link
Tuesday, January 08, 2013 6:13 AM
Can we look forward to Part 4 soon?
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