Category Archives: 1. bowtie6

ECOTEC Engine

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The 3.4 litre V6 that has faithfully powered bowtie6 for the last 15,000 miles has been a great engine and has provided enough power to obliterate a frame.  However,  it is dated, cannot be modified furthermore and the ECM cannot be re-programmed.  An LS engine although attractive would be too heavy.  Colin Chapman had it right:  to go fast, one must keep weight at an absoloute minimum.  So a highly powerful yet lightweight engine is the ticket.

The GM ECOTEC is the answer.  This engine is truly magnificent.  The engine is all aluminium 2.4 litre twin cam 4 cylinder with variable valve timing.  In stock form, it produces 177hp and with a little boost can easily produce 250hp at the rear wheels.  The sky (no pun intended) is the limit.  I’ll let you Google for more info on the engine – suffice to say, bowtie6 has to have one.

So let me tell you about my ECOTEC engine…

Ever heard of Mallett Cars?  These folks would take a brand new Pontiac Solstice or Saturn Sky and pull the Ecotec out.  In the cavity left behind they would stuff an LS2 or LS7 V8.  Well, my ECOTEC is one of the ‘take out’ engines they took out of a Solstice/Sky.  I was lucky enough to find a gentleman that had purchased 40 of these engines.  To put icing on the cake, I was able to hand-pick my engine/tranny combo and (get this) I found one that has only 4 miles on it.  The donor car was obviously driven off a transporter and immediately modified.  Lucky me!

So where are the pictures to prove it?  Read along…

Lets start with the engine as I purchased it.  This is the engine fully crated in one of the original “LS” V8 crates.  This shows this was the “025” conversion made by Mallett Cars.

Crated ECOTEC engine…

Moving right along, here is another picture taken of the crate once we got it on a trailer:

Crated ECOTEC on trailer

Another closeup of the crate:

Crated ECOTEC closeup

And finally, the piece d’resistance.  The sticker showing four miles on the engine.  The “V8-025” matches the same numbers on the crate and once we took the crate apart we found more stickers with the same info on it.  I have no idea who “Bob Anderson” is but I presume his Solstice/Sky at one time had this engine under its bonnet.  Soon it will be powering bowtie6.

ECOTEC mileage sticker… Yes! 4 miles!

Frame Failure!!

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All good things come to an end.  In this case, the “original” (and I say that loosely) frame has endured a frame failure.  Yep.  There is a tear several inches long on the passenger side along the rear suspension mounts.  Upon closer inspection the driver’s side has stress marks and I’m sure it is not far from failure too.

I noticed the problem back in November of 2010.  While driving, I started hearing some unusual sounds and sure enough after putting the car on jackstands a close inspection revealed the tear.  No pictures yet, but I’ll have some soon.  Suffice to say, the frame is toast and there is no way to repair it.

Unfortunately, the TR6 frame is extremely flimsy and quite frankly it is poor at best.  And no, I’m not saying this  because mine failed.  I’m saying this for the benefit of those folks that think they can put larger or modified stock engines and the frame will be able to withstand the extra power.  Well, if you believe that you are fooling yourself.  These frames are made of 10 gauge material and is not of the best design.  It is a “U” shaped affair with an extra plate, spot welded.  Add to that years of rust from within the tubes and you have a recipe for failure.  My frame was in excellent shape when I started the project and was reinforced and properly prepared.  Even after all that attention, it failed.

I’ve had several people ask why “original” frames have held up with V8’s and mine failed.  I guess it boils down to the fact that I have put 15,000 miles on my frame and have actually stressed it enough to cause it to fail.  So if you are considering something like what I have done with bowtie6, I would highly recommend thinking all your options.

And so the next step in the evolution of bowtie6 begins…

A new, bespoke frame is in the works.  The new frame is being made of square tubing with fresh stock.  No expense is being spared on the materials.  The frame will use the factory stock front suspension components with one big difference:  the springs/shocks are being replaced with true coilovers.  The great advantage of this will be there is no more need for a spring compressor since the coilover is not only adjustable but fully encapsulated and there is spring under tension to worry about.

As far as the rear suspension?  The crappy factory trailing arms will be ditched along with the Nissan diff currently in bowtie6.  Instead I will be using an 8 inch solid axle, with four point suspension, coilovers and swaybar.  Why?  Well, the IRS is really not an option.  For the expense of new halfshafts, new diff, and all the extra “stuff”, I can have a fully posi-traction custom built solid axle that will withstand plenty of horsepower…

Which leads to the next major improvement…

Yes, bowtie6 is getting a new engine.  The 3.4 litre V6 currently in bowtie6 is pretty much maxed out.  There is no more I can do to it.  Plus the ECM is not programmable.  So what are my options?  A brand new ECOTEC 2.4 litre 177hp crate engine and matching 5 speed gearbox has been sourced.  ECM reprogramming?  No problem – this engine’s ECM is fully re-programmable.  Needless to say, the sky is the limit…

I’ll have more info on my ECOTEC in the next installment.

Catching up…

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The past four years have been great in the life of bowtie6.  The car has performed flawlessly logging almost 15,000 miles.  Several major improvements have been made:

Cam & Rockers

The stock cam has been replaced with a high-lift ratio.  The specs on the cam explained the change would take effect in the 1200-1500rpm range and last until redline.  This was to give a much smoother powerband.  In additiont to the high lift cam, a set of roller rockers has been installed along with a set of matching performance valve springs.

Heads

I was able to find a set of lightly used heads for this engine.  They were taken to a local machinist and he ported, polished and flowed the heads.  A three angle valve job was also performed.  The intake ports on the stock heads has a ‘sharkfin’ to help promote air flow.  While this improves low-rpm flow, it restricts flow at higher rpm ranges.  The fins were completely ground off and this made a huge difference.  All intake ports were matched to the lower intake manifold and the exhaust ports matched to the custom headers.  There is definitely truth in the statement that “horsepower is in the heads”.

Intake

The stock intake had been re-worked once by installing the throttle body from an LT1 V8.  This basically replaced the single butterfly with two large butterflies on the intake.  However, the rest of the intake was still very restrictive.  So, the intake was re-worked yet again making it handle a large amount of air volume.  To improve airflow as much as possible an airfoil for the throttle body was installed.

Conclusion

The cam and intake modifications made a great difference.  Soon after that was all done, I took the car to a local dyno for measurements.  The total figures produced 153hp at the rear wheels with 189ft/lb torque.  Quite respectable numbers.

Then came the heads.  Wow!  What a difference.  The upgrade bumped up power to 188hp at the rear wheels and 226ft/lb torque.  At the dyno, the exhaust gas was analyzed with an O2 sensor and was found to be spot-on.  On the first dyno session the ECM was not making things very efficient at higher RPM’s.  With the new heads, larger injectors and an adjustable fuel pressure regulator we were able to get much more efficient results.  This made the extra power at the wheels.

Unfortunately this is the end-of-the-line for the 3.4 litre V6.  The ECM on this engine is OBD1 and not tunable.  That is why we had to fiddle with the AFPR and run bigger injectors.  The powerband on this engine is very smooth and redline can be achieved right quickly.