j35

J32 V6 Engine Swap

I’ve been considering an engine swap for a while.  The F20C/F22C is an absolutely amazing engine; engaging to drive and responds well to forced induction.  On top of all that, it’s pretty cheap to operate and can take track punishment for a long time and when it fails, rebuilding is easy and inexpensive.  All that being said, the original intent to supercharge my S2000 was to give it the power needed to run with the fastest cars on track.  With the stock engine I was stuck behind them in the corners and unable to pass on the straights.  The supercharger changed that.  Of course, now there are lots of 500-600 hp cars on the track that still walk away on the straights but I guess that’s the ever evolving progress of technology.  I am actually really happy with the current speed of the car and have no desire to have higher top speeds.  140 mph through turn 1 at Pacific Raceways is scary enough.

I really enjoy the instant response of a naturally aspirated car or supercharged car.  My daily drivers are a 2015 WRX and a 2001 Dodge RAM Turbo Diesel 24V.  I’m not against turbos at all but I really don’t like them for track use.  Turbo lag, throttle response, heat, etc all add up to frustration for me.  For the racing I’ve been doing lately, the classes are power-to-weight based and my small displacement high revving 4-cylinder makes a very peaky power curve.  Adding a Rotrex supercharger bumps the whole curve up but still only makes peak hp in a very limited rpm window which means 95% of the time, I’m not operating at peak power.  The top cars in these classes are detuning the engines to create a flat hp curve in the operating range using throttle by wire mapping, inlet restrictors, or programmed wastegates.  To get a flat hp curve, you really need a positive displacement supercharger, turbo, or bigger engine displacement.  For me, a larger naturally aspirated engine seems like the best choice for optimal throttle response, minimal complexity/maximal reliability, minimal heat, etc.

An LS swap makes a lot of sense.  It’s been done many times, the motors are powerful, light, and compact.  For the track, these motors have more power than I want/need.  This would require a new and heavy transmission and differential to handle the increased torque.  To get to my ideal hp/wt ratio, I’d need to detune the engine quite a bit so now I’m dragging around a bunch of heavy components to support a detuned engine.  Also, there are some clearance issues including firewall and steering rack.  I’d rather not relocate the steering rack and any modifications to the subframe results in penalties under the race class I run in (treated as a tube frame chassis).
The J-series V6 from Honda is the option I’m pursuing.  I’m starting with a J32A2 from a 2001-2003 TL Type-S and will likely swap in a crankshaft from the MDX 3.7 and 3.5 rods and pistons at some point to create a 3.6 liter high compression motor.  No replacement for displacement – as they say.  Some of the advantages include the ability to use the S2000 transmission (which is one of my favorites ever) and differential which has been reinforced to handle increased power.  I can also use my existing Exedy Hyper Single clutch.  This means stock axles and prop shaft can be used as well.  The engine is very compact and has no interference issues other than the oil filter which can be solved with a remote mounted oil filter.  Ultimately, I’m hoping for around 325 whp and lots more torque than I currently have with the supercharged F22C.  I think the weight will come within 20-30 lbs of the current engine/supercharger/intercooler.  The torque and lack of revs will change the character of the car for sure.  I’m keeping my SC’d F22C in case I don’t love the J-swap.

This will be a slow project as I’m currently rebuilding a Formula SAE car which I plan to race in 2017.  The FSAE car will be priority, however, I’m pretty excited for this swap project so I’ll be working on it fairly often.  There will be lots of learning, fabrication, and likely a few mistakes along the way.  This is still a fairly rare swap and not well documented so lots of this project will require custom solutions.  You can also follow the progress on Instagram: @sectoronedesign

Here are some progress pictures so far:

Lots of “Honda Power” in the shop at the moment

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Adapter Plate and engine mounts needed some modifications to fit:

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Picked up a magnesium intake manifold from a 2009 TL SH-AWD

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Much lighter than the J32A2 aluminum intake manifold and with larger T-body opening:

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