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Gearbox and Engine Oil Cooler Upgrades

Over the winter I have decided to do something about the gearbox oil temperatures, which when on track can get seriously hot. One of the downsides of the M32 gearbox is its inability to deal with heat effectively. After fitting a gearbox oil temperature gauge I have been able to monitor the gearbox oil temperatures on the road and (mainly) on track.

Without a gearbox oil cooler the gearbox oil temperature on track days can quickly rise to 120+ degrees C (if you let them) when the car is driven hard which can degrade the gearbox oil quickly. On cruise on the road the gearbox oil temperature tends to sit pretty stable in the mid 70’s, but any hard use will again cause the temperature to rise. Because the M32 gearbox does not dissipate heat readily the only way to bring the temperature down is to stop the car and leave it idle for about 20 minutes or so, and the oil temperature drops to mid 70′s and then another 20 minutes on track will bring the temperature back up again and so the cycle continues.

Using a very high quality fully synthetic gearbox oil (75w-90) is essential and so are regular gearbox oil changes.

The addition of a gearbox oil cooler will keep the gearbox oil temperature under control when on track and from temperature monitoring on track is (I would say) essential for track use.  As far as the car is concerned on track the high gearbox oil temperature is the one thing that hinders its use, because everything else such as water temperature (Enlarged Pro Alloy Water Rad), inlet air temperature (Full Height Front Mounted Courtenay Sport Racing Intercooler manufactured by Pro Alloy, brakes (Alcon Monobloc 4 Pot calipers with 356mm x 32mm alloy belled discs) are absolutely fine and under control.

So fitting a gearbox oil cooler will require an additional oil pump and an external oil cooler matrix to cool the oil.

Also requiring consideration is the engine oil cooler. Having data logged the engine oil temperature on an Astra VXR race car producing around 280-290bhp the factory fitted water cooled engine oil cooler can keep the temperature under control.However further power increases will put additional strain on this.

So under consideration is also an external engine oil cooler in place of  the OE engine oil cooler which is a smaller water cooled laminova core, mounted to the rear of the block just under the inlet manifold and cooled by the engine coolant.

With the addition of a gearbox oil cooler, this then potentially means two external oil coolers (one for the engine and one for the gearbox), and the associated problems of where to mount them…..

Due to space constraints a plan came to light. The thought process is to use the original laminova core (originally the engine oil cooler) as a gearbox oil cooler because it can cope well enough with cooling the engine oil (which is a 5 litre capacity) and since the gearbox only has 3 litres of oil it should be more than capable of keeping the temperature under control. Also by removing the engine oil cooler and making it an external cooler, the thermal shock from the heat of the engine oil is being removed from the engine coolant. And when running on track the water temperature generally never exceeds 95 degrees C, which is a perfectly acceptable gearbox oil temperature.

So if I am adding an extra oil cooler matrix I thought I would make it for the engine oil and use a bigger external oil cooler because the car is getting to the limits of the factory oil cooler’s capabilities. By doing this I am then only adding one external cooler matrix (for the engine) and re-using the exiting engine oil cooler for the gearbox oil rather than having to add two external matrix (one for the engine AND one for the gearbox.)

Steel Rods

Late 2013, and in the quest for even more useable power on track, the next step was to add a high flow inlet manifold (more in a later post) and a set of H-Beam steel rods with ARP rod bolts. The steel rods are being added for strength and safety (in case of an over-rev) and to take advantage of the extra power available at the top end afforded by the already fitted K06 turbocharger and the soon to be fitted Inlet Manifold. The steel rods will allow the engine to rev to around 7,500 rpm. The factory fitted pistons are a Mahle forged piston and are very strong for a factory piston capable at up to 500bhp so more than adequate for this track day application.

The H-Beam steel rods were taken to my local engine machine shop (who do a lot of motorsport engine prep) and have been balanced end to end to within 0.5 grams. Once returned it was time to fit them.

The engine was opened up; airbox removed, turbo removed, inlet manifold removed, cambelt removed, rocker cover off, camshafts and lifters out then the head was removed and placed on the workbench. At the bottom end the sump and upper sump carrier were removed, the baffle plate, oil pickup and bridge came out and then the big ends could be removed and the pistons and factory rods could be lifted out from the top, ensuring the bearing caps and rods were dot punched to identify them and keep them together should the engine ever go back to standard.

The news was good when everything came apart. The engine has had regular oil changes and the bores are in excellent condition (which to be honest was what was expected), not showing the mileage it has covered (which is currently a shade over 87,000 miles) and with the original hone marks in the bores still visible and the pistons are also in excellent order. The cams are also showing no signs of wear.

Once removed the factory pistons and rods were also taken to the workbench where the OE rods were swapped over for the steel rods and the piston rings were checked and repositioned to ensure they were in the correct orientation. At the same time all 16 of the Valve ten Oil Seals, some of which were leaking on the exhaust side, were replaced and when the exhaust side stem seals were replaced 8 valve stem oil seal retainers were also fitted. These help prevent the stem seals from lifting off and leaking in future.

Whilst apart the cylinder head, cam shafts, oil pick up pipe, oil pan carrier, sump pan, baffle plate and bridge were all put into the Safety Kleen tank and thoroughly cleaned prior to being refitted.

The pistons and rods were then refitted into each bore with new Mahle big end bearings and the big end bearing caps fitted and then secured with the ARP rod bolts, torqued up to 55 lb/ft with ARP Assembly Lube. The engine was then put back together with new gaskets, seals and new head bolts and timed up ready to go.

Winter Rework

Winter rework will soon be underway, to further improve the car, although it is extremely capable at 300bhp when last run up on the rolling road. The factory inlet manifold is pretty restrictive so on track the car relies quite a lot on the spread of torque the car offers, especially mid-range because peak power is around 5,600 rpm and much above 6,250rpm the engine power really drops off.

A little more power at the end of the straights is always useful to get past cars that on occasion (quite often as I have found out) don’t lift down the straight, despite the fact you have spend most of the previous corners ‘pushing’ them.

So the plan; make the best use of the fitted K06 turbo, fit a higher flowing inlet manifold to give more power and torque above 4,000 rpm, and still produce good power at 6,000 rpm where the current set up really starts to drop off significantly and continue to produce good power at 7,000-7,500 rpm (ideally somewhere around 315-320bhp).

Added to this will be changes to the engine oil cooler, the addition of a gearbox oil cooler, oil temperature (engine and gearbox) and boost gauges plus a replacement set of Pagid RS29 front pads (they are just about due for change having covered 2,000 miles!) and a new set of wheels and tyres.

Track Day November 2013 Snetterton

The final Track Day for 2013 was at Snetterton on the 300 Circuit with Open Track www.OpenTrack.co.uk on Monday 4th November 2013.

As usual Snetterton weather provided everything during the course of the day! Dry, bright, sunny, wet and damp. Great to get out on track for one final time, and looking forward to the closed season changes to the car, which will bring high improvements for 2014 to what is already an ultra capable track day car.


Thanks to Tony Harrison for the On Track Photographs © Copyright Terms: http://creativecommons.org/licenses/by-nc/2.0/deed.en

Polyurethane Exhaust Mounts

Added to the car to help further reduce any exhaust system  movement are these PowerFlex uprated polyurethane exhaust mounts. Stiffer with much less give holds the exhaust more solidly with less movement. Ideal for track use where the tailpipe can move and touch the rear diffuser, often melting it in places where it touches.

The Piper 3″ system uses 6 of these mounts.

Powerflex Exhaust Hanger

Powerflex Exhaust Hanger

Track Day September 2013 Snetterton

Trackday at Snetterton on the 300 Circuit with Open Track www.OpenTrack.co.uk on Sunday 15th September 2013

A changeable day; dry, bright and sunny in the morning and damp occasionally wet in the afternoon.

Thanks to Tony Harrison for the On Track Photographs © Copyright Terms: http://creativecommons.org/licenses/by-nc/2.0/deed.en

Track Evening June 2013 Snetterton

An inexpensive Track Evening at Snetterton Circuit became available with Javelin, on Thursday 27th June 2013 and it would have been rude not to! Dry for the most part, but it became damp towards the end of the evening, but no great dramas. Photograph by http://www.xtreme-sports-photography.co.uk © 2013

On Track @ Snetterton

On Track @ Snetterton

Track Evening June 2013 Snetterton

Another outing at Snetterton, this time a track evening on Monday 10th June.


Track Evening organised by OpenTrack www.OpenTrack.co.uk
Thanks to Tony Harrison for the on track shots © Copyright Terms: http://creativecommons.org/licenses/by-nc/2.0/deed.en

Uprated Gearbox Engine Mount Insert

Having previously (in 2012) filled the original gearbox side engine mount with sikaflex to stiffen it and reduce movement due to the lack of an uprated gearbox mount, Powerflex brought out (in early 2013) a polyurethane gearbox mount insert having been asked to manufacture it by Courtenay Sport. This insert reduces the movement in the factory mount and the black insert shown here is the race/track spec stiffest mount manufactured out of 95 Shore A material. Since Powerflex sent me an insert to try out, a new OE side mount and the uprated insert have been fitted to the car.

OE Gearbox Engine Mount with Uprated Polyurethane Insert

OE Gearbox Engine Mount with Uprated Polyurethane Insert

This mount makes a massive improvement in reducing flex in the factory mount and really compliments the other Vibra Technics mounts well.

Track Day February 2013 Snetterton

First track day of 2013, a dry, bright, sunny but cool Snetterton Circuit. Sunday 17th February.


Track Day organised by OpenTrack www.OpenTrack.co.uk
Thanks to Tony Harrison for the on track shots © Copyright Terms: http://creativecommons.org/licenses/by-nc/2.0/deed.en

Astra VXR Sprint.....

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