Category Archives: ECOTEC Powertrain

Ecotec 2.4 liter engine

Details About an ECOTEC Powered TR4

After the success we had with bowtie6, my cousin Jim and I had many conversations on improving the concept.  I remember countless hours of discussions next to the space heater in Jim’s well equipped shop several winters ago.  We quickly zeroed-in on the engine:  the Ecotec as fitted to the Pontiac Solstice mated to the Aisin 5 speed gearbox would supply a powerful and reliable drive-train.  It would also offer a PCM that we could tweak with a laptop.  We also decided a Triumph or MG would be a good platform for the Ecotec.  Finally, we would subscribe to the ideas that Anthony Colin Bruce Chapman based his designs upon:  keep wight at a minimum.

Eventually, we got word there was a local fellow with several cars in his basement that had to be sold  Needless to say, Jim and I quickly grabbed our gloves and jumped in the shop-truck and headed out to this fellow’s basement.  Sure enough.  We found a 1964 TR4 as well as a Datsun 2000 roadster.  The Datsun was our first choice since it is the more “exotic” of the pair however it was missing entirely too many parts.  Jim decided the TR4 would be the best choice.  A few days later we arrived with a trailer and brought the TR4 home.

I could write about all this for hours but I think you want to see pictures and not a bunch of words, so let me fast forward to the present and show you what Jim’s TR4 looks like today.  Unfortunately I cannot cover the entire car in one article; I’ll break this up into several.  Today, I’ll start with the outside.  After all, beauty can’t be only skin deep, right?

As you can see in the picture above, the nose of this TR4 incorporates many subtle changes.  For starters, the turn signals are gone.  They are now hidden behind that hand-made aluminum grill.  The front bumper is also gone and the oval air inlets below the grill have stainless mesh behind them.  Finally there is a hand formed “air dam” with two “nerf” bars on the roll pan.  Jim likes his “nerf” bars – Steve if you are reading this, I am sure you will agree with me.  🙂

The picture above shows the new bonnet.  When I mean “new”, I mean this piece was formed entirely from aluminum.  If you look closely, you will see the “bulge” is missing – I guess it is a matter of choice but this is the way Jim decided to build the bonnet.  The trick to making this bonnet was piecing together several sections.  They were all carefully formed on the English wheel and TIG welded together.  The following gallery shows what the back of the bonnet looks like.

But… Before you start clicking on all these pictures take a look at the first one of the set.  There is a small recess, wide enough for two fingers to be used to lift the bonnet once the latch is released.  Pretty cool, huh?

Next you can see the backbone of the bonnet.  This backbone is also made from aluminum and is not welded, instead it has been bonded to the backside of the bonnet with automotive epoxy glue.  Finally, take a look at the third picture.  If you look close enough, you can see some of the hammer marks left from when Jim formed the headlight bulges.  Yes, all this was carefully welded and shaped just like it in the glory days of hand formed bodies.

The next gallery shown above, displays the hard top Jim made for the TR4.  This top is entirely made of aluminum and just like the bonnet, is extremely lightweight.  Again, many pieces formed by hand and on the English wheel, TIG welded and carefully finished.  If you look at the surface of the top (see second picture) you will see ridges formed by Jim’s Pullmax machine.  These ridges are there to add strength and to prevent the top from oil-canning.  Finally, to keep weight down Jim used thin Plexiglass in the windows instead of glass.  Oh and the side windows open; Jim made special hinges to allow the side windows to pivot.  The following collection of pictures shows what the top looks like from the back and from the sides.

The back third of the top has a small taper.  It is also formed in such a way to give the rear glass a curved look.  At first, one would think this would hinder visibility but the seats are very low in this car, and outward visibility is excellent.  I think it looks very cool!

Finally is this picture from the back of the car.  The bonnet is also different from stock.  Yep, you guessed it.  It is also formed from aluminum.  Jim made a similar backbone frame for it and it is extremely lightweight.  As if that were not enough, take a look at the rear bumper.  This one is not as wide as the ones Jim made for bowtie6, but is just as lightweight.  This bumper also is different from mine in that it’s finish is made by simply wiping it with ScotchBrite.  This gives the aluminum a muted, matte finish.

I hope you have found this interesting.  I’ll have more about Jim’s TR4 in future articles, so stay tuned!  😉

Engine Fitment in the TR4

A fact has been brought to my attention:  “Amazing that in the TR link, with all the hype about the engine, there is not a single pic of the engine in the car!”.  My bad.  Time to make amends; time to really document the engine in the car.  Some facts:

  • The engine is a 2.4 litre VVT ECOTEC from a Pontiac Solstice
  • The transmission is a five speed AISIN also from a Pontiac Solstice
  • The wiring harness has been lifted from the Solstice and modified.  It has been vastly simplified.  How?  RTFM.  Seriously, all the info is available in the Factory Service Manuals – trick is finding it.  😉
  • The ECM has been reflashed in order to disable VATS.
  • This ECM is fully programmable – in this case we have HPTuners on a laptop.  Right now, we are running the stock configuration – hopefully soon we will spend some quality time on a dyno and then tweak the thing.
  • The stock plastic intake has been replaced.  The intake you see in the pictures was all hand made from aluminium and welded to a flange in order to make the runners match the intake ports.  This is done for a reason:  the original plastic intake does not give enough room for the steering column in a TR4.
  • The stock throttle body with its fly-by-wire controls has been retained.
  • The exhaust manifold has been discarded.  Like the intake manifold, the header is all hand made from stainless.  This is also welded to a special flange in order to match the ports on the engine block.


As stated above, the throttle remains fly-by-wire.  There is nothing ‘weird’ about this.  Actually it is extremely fast and the throttle body reacts to small inputs as well as full throttle acceleration (done that many times).  Matter of fact, my wife’s HHR (it has a 2.4 Ecotec as well) has the same fly-by-wire setup and it is very responsive.  I have no problems running this furthermore this is the way more and more modern cars operate.

The intake and exhaust manifolds have been altered and this is done for a reason:  the body needed to remain intact.  There has been some work done to the tunnel though.  A new transmission cover has been made as well as the driveshaft cover between the seats.  I don’t have a way to show that since the TR4 is assembled now.  However when I put bowtie6 back together once his ECOTEC is in place, I’ll have better pictures to show of how that all fits.

If you have questions and/or comments, please make an entry here – I’ll try to answer back!  Keyword here is:  dialogue!  🙂

ECOTEC Powered TR4

ECOTEC engines in British sports cars are a reality.  These engines offer great power-to-weight, excellent mileage and a wonderful exhaust note.  Folks, this is the way to go when modifying a British sports car.  The proof of concept was my cousin Jim’s TR4.  He has been working on this car for a couple of years, and little by little it has become a reality.  There are so many awesome things about this car!

The frame is hand built.  This is the same design that is being used for bowtie6‘s new frame.  My frame will be a simpler version of the one on the TR4 but basically will consist of the basic principle:  square tubing, modified TR6 front suspension, and a 4 point suspension rear axle with posi-traction.

The TR4’s body has been left stock, except for the bonnet, boot lid and hard top.  These components have been hand-made out of aluminium.  Yes, aluminium.  The main directive for the TR4 was to make it as light as possible and by making these body panels from aluminium a great deal of weight was saved.

The engine is an ECOTEC 2.4 litre and matching five speed from a Solstice.  Last year, the car was tested with the smaller 2.2 litre version.  We found the engine to be awesome and very responsive.  The ECM had to be fiddled with a little, but the result was quite impressive.  If you want to see a video of the car at that time, check this out:  ECOTEC TR4 video

Pretty cool huh?  Well – that was done about a year ago and showed the car in pretty rough state.  It was in primer, things were not bolted down tight, the interior was missing and the wiring was still being worked on.  Some 1500 miles were put on the car by Jim and all pointed in the right direction:  the care was lightweight, very responsive and the frame provided a very tight, solid feel.

The TR4 was fully disassembled, this time for its final assembly including a new 2.4 litre ECOTEC, paint and interior.  This time it is for real!  After many months of work, this is what the first ECOTEC powered  TR4 looks like: