The £7700 Corvette C6
Discussion
I had a call from Dick Lovett, Bath a few days ago to say the bonnet vent had arrived, quicker than any of us expected.
First impressions are that for less than £50 it's a bargain, nicely made in gloss black. The profile follows the curve of the bonnet well, although the edges will overhang the dip in the bonnet.
A quick diversion on the way home through Castle Combe village, just because it's pretty.
How it looks from a couple of different angles, with clips on the underside for a push fit.
I then waited two days, gave myself a talking to to check that I really wanted to make a hole in the bonnet, decided I did as it was for function rather than looks and grabbed the power tools.
First off, positioning. To be most effective it needed to be positioned a few inches behind the radiator and fan shroud, which in a C6 is some way rearward of the headlights. So, I drilled a centre hole just above the inner brace, from the inside out, that way I could do the rest of the work from the front of the car.
No going back now!
Measure 15 times, cut once, it took me hours to be happy! I drew around the outside shape onto masking tape, fortunately the clips are exactly 5mm inside of the edge, so a second line drawn inside the first and I was almost ready to get chopping. The bonnet, like the rest of the bodywork is a unique to Corvette thermoplastic fibreglass material, best cut with a spinning disc rather than a jigsaw. I used a fine metal blade in the angle grinder for the bulk of the cut and a Dremel with metal disc for the corners.
It would have made a lot of dust, so with facemasks a bit scarce at present I clamped the vacuum nozzle to a camera tripod so it sucked away the dust as it was made, no mess at all.
The cut went well, although I'd have left a little more material on each end if I were to do it again (as you can see on the next photo), not a problem though. I popped the vent in first time, nice and snug.
As I thought the extreme left and right edges were proud of the bonnet where it falls away. I popped it out, donned the heat proof gloves and used a heat gun to gently curve the edges down. It's good enough I think, if not at professional standard. If I'd have moved the vent further towards the windscreen where the raised centre section of the bonnet gets wider I'd have probably not needed to melt anything, but then it would be nearer the high pressure screen base and directly over the engine covers, so not as effective.
I trimmed the liner with scissors as it looks neater.
As it was getting dark I took a photos with a torch beneath so you can see the vent is directly over the space between heads and fan shroud, I can look down and see the inlet pipe, part of the pas reservoir, a little of the throttle body, belts, alternator bracket etc.
I like that the vent sits horizontal to the ground and that the rear of the vent protrudes down into the engine bay further than the front, better for the air to egress that engine bay. I've decided not to buy the £150 BMW mesh as it looks just fine being left open.
Yesterday I went for a solo drive to Lynmouth (excercise walking up the hill to Lynton), across Exmoor. The section of the A39 between Porlock and Lynmouth is one of my favourite driving roads. It provided a nicer background for the 'after' photos than under my car port, despite the mobile phone pics.
A drivers eye view
Of course I didn't do this for appearances sake (else I'd have left the poor car alone), but to reduce intake air and coolant temps. Did it make a difference? I'm relieved to say, yes, it has. For the last month's worth of journeys I have had the coolant temps displayed on the dash, with the IATs on the Android head unit. Every journey is different, but with ambient temperatures being between 70 and 77 degrees F yesterday and a mix of motorway cruise and brisk moorland driving I believe the coolant temps are between 5 and 10 degrees lower. 77mph on cruise control had the coolant temps around 189 to 192F.
A few weeks ago I slightly opened the radiator shroud, to allow more outside air to reach the air filters. This was typically giving around a 10F above ambient temps on a typical drive (not stuck in traffic). Yesterday I was seeing temp differences as low as 4F, indicating the hot air was being drawn out of the engine bay.
The real test will be at Castle Combe in a couple of weeks.
Cheers, Dave
First impressions are that for less than £50 it's a bargain, nicely made in gloss black. The profile follows the curve of the bonnet well, although the edges will overhang the dip in the bonnet.
A quick diversion on the way home through Castle Combe village, just because it's pretty.
How it looks from a couple of different angles, with clips on the underside for a push fit.
I then waited two days, gave myself a talking to to check that I really wanted to make a hole in the bonnet, decided I did as it was for function rather than looks and grabbed the power tools.
First off, positioning. To be most effective it needed to be positioned a few inches behind the radiator and fan shroud, which in a C6 is some way rearward of the headlights. So, I drilled a centre hole just above the inner brace, from the inside out, that way I could do the rest of the work from the front of the car.
No going back now!
Measure 15 times, cut once, it took me hours to be happy! I drew around the outside shape onto masking tape, fortunately the clips are exactly 5mm inside of the edge, so a second line drawn inside the first and I was almost ready to get chopping. The bonnet, like the rest of the bodywork is a unique to Corvette thermoplastic fibreglass material, best cut with a spinning disc rather than a jigsaw. I used a fine metal blade in the angle grinder for the bulk of the cut and a Dremel with metal disc for the corners.
It would have made a lot of dust, so with facemasks a bit scarce at present I clamped the vacuum nozzle to a camera tripod so it sucked away the dust as it was made, no mess at all.
The cut went well, although I'd have left a little more material on each end if I were to do it again (as you can see on the next photo), not a problem though. I popped the vent in first time, nice and snug.
As I thought the extreme left and right edges were proud of the bonnet where it falls away. I popped it out, donned the heat proof gloves and used a heat gun to gently curve the edges down. It's good enough I think, if not at professional standard. If I'd have moved the vent further towards the windscreen where the raised centre section of the bonnet gets wider I'd have probably not needed to melt anything, but then it would be nearer the high pressure screen base and directly over the engine covers, so not as effective.
I trimmed the liner with scissors as it looks neater.
As it was getting dark I took a photos with a torch beneath so you can see the vent is directly over the space between heads and fan shroud, I can look down and see the inlet pipe, part of the pas reservoir, a little of the throttle body, belts, alternator bracket etc.
I like that the vent sits horizontal to the ground and that the rear of the vent protrudes down into the engine bay further than the front, better for the air to egress that engine bay. I've decided not to buy the £150 BMW mesh as it looks just fine being left open.
Yesterday I went for a solo drive to Lynmouth (excercise walking up the hill to Lynton), across Exmoor. The section of the A39 between Porlock and Lynmouth is one of my favourite driving roads. It provided a nicer background for the 'after' photos than under my car port, despite the mobile phone pics.
A drivers eye view
Of course I didn't do this for appearances sake (else I'd have left the poor car alone), but to reduce intake air and coolant temps. Did it make a difference? I'm relieved to say, yes, it has. For the last month's worth of journeys I have had the coolant temps displayed on the dash, with the IATs on the Android head unit. Every journey is different, but with ambient temperatures being between 70 and 77 degrees F yesterday and a mix of motorway cruise and brisk moorland driving I believe the coolant temps are between 5 and 10 degrees lower. 77mph on cruise control had the coolant temps around 189 to 192F.
A few weeks ago I slightly opened the radiator shroud, to allow more outside air to reach the air filters. This was typically giving around a 10F above ambient temps on a typical drive (not stuck in traffic). Yesterday I was seeing temp differences as low as 4F, indicating the hot air was being drawn out of the engine bay.
The real test will be at Castle Combe in a couple of weeks.
Cheers, Dave
Edited by Fishy Dave on Tuesday 2nd June 21:27
That looks great OP, but I hope you didn't spend too long in Castle Combe village!
They don't seem to like brightly coloured cars in their villages.
https://uk.news.yahoo.com/ugly-yellow-blamed-for-r...
They probably wouldn't be too keen on a red LHD V8 Corvette.
They don't seem to like brightly coloured cars in their villages.
https://uk.news.yahoo.com/ugly-yellow-blamed-for-r...
They probably wouldn't be too keen on a red LHD V8 Corvette.
Mr Tidy said:
That looks great OP, but I hope you didn't spend too long in Castle Combe village!
They don't seem to like brightly coloured cars in their villages.
https://uk.news.yahoo.com/ugly-yellow-blamed-for-r...
They probably wouldn't be too keen on a red LHD V8 Corvette.
Thanks, I sneaked through with the exhaust in quiet mode and switched off when snapping the photos. They don't seem to like brightly coloured cars in their villages.
https://uk.news.yahoo.com/ugly-yellow-blamed-for-r...
They probably wouldn't be too keen on a red LHD V8 Corvette.
I remember that yellow Corsa news, looks like it wasn't Castle Combe though.
Thanks both, it took hours before I made that first cut. It was a bit 
Painting the vent body coloured was my plan, I bought a can of Victory Red for the job, but the finish of the BMW part is good and although the black makes it stand out it's grown on me. What do you all think? Leave it black or paint it body coloured?
Painting the vent body coloured was my plan, I bought a can of Victory Red for the job, but the finish of the BMW part is good and although the black makes it stand out it's grown on me. What do you all think? Leave it black or paint it body coloured?
Spur of the moment I contacted Circuit Motorsport at Castle Combe, to fit in a basic power run. This was mostly curiosity to see how many of the 400 horses have gone lame or escaped in the last 210,000 miles/13+years. I've known the operator, Leighton, on and off for many years, he's a good guy and will present the figures accurately.
As an aside, whilst the car was being strapped down I attached two bits of wool, one underneath and one on top and in front of the bonnet vent, to check the direction of airflow. In short of the wool was sucked down and through the vent then the plan had gone horribly wrong, if the tuft underneath was drawn up and through the vent the air was flowing in the right direction.
As you can see, with the fans turned on the wool pops into view, confirming the airflow direction is as planned.
Secondly, the rolling road result.
Rolling road results are notorious for varying depending on the day, location, make and operator, having said that, I'm happy enough to accept this one. To be so close to factory figures is impressive. Whilst my car sports a few modifications none of them contribute to power except the NPP exhaust (factory back boxes with dual mode) which was supposed to add 6bhp iirc. The cooling mod may help to lessen the chance of timing being pulled, although it still happened on one unrecorded run.
Leighton plugged in his laptop loaded with HP Tuners, just to monitor knock and timing, but aside from that one run (likely caused by slightly high intake temps) everything looked normal.
Oh and this was done on Morrisons finest super unleaded!
Edited by Fishy Dave on Thursday 11th June 16:45
Oh well, that's it, then; I'm Morrisons man from now on!
They're hugely impressive figures for an engine with so many miles on it; you're obviously looking after it very well. That TG mission where they took the exotic sports cars, and dyno'd them to prove how many donkeys had run away showed, in effect, just how good these engines are.
You can't beat a good Chevy!
They're hugely impressive figures for an engine with so many miles on it; you're obviously looking after it very well. That TG mission where they took the exotic sports cars, and dyno'd them to prove how many donkeys had run away showed, in effect, just how good these engines are.
You can't beat a good Chevy!
Thanks both I'd have chosen a higher quality fuel if I'd thought in advance, ah well, doubt it would make any difference to a simple power run.
I believe mine is the only C6 they've had there. Four or five of my previous cars have either had power runs there or been mapped on those rollers, but accuracy can change, so no way of knowing whether that figure is strong or realistic. My seat of the pants confirms it's still pulling well though.
I'd have chosen a higher quality fuel if I'd thought in advance, ah well, doubt it would make any difference to a simple power run. I believe mine is the only C6 they've had there. Four or five of my previous cars have either had power runs there or been mapped on those rollers, but accuracy can change, so no way of knowing whether that figure is strong or realistic. My seat of the pants confirms it's still pulling well though.
Hello,
A number of people have commented they'd be interested in buying a cheap Corvette, I just noticed this C5 manual for sale: https://www.pistonheads.com/classifieds/used-cars/...
I don't know the car or seller but with those miles it looks good value.
A number of people have commented they'd be interested in buying a cheap Corvette, I just noticed this C5 manual for sale: https://www.pistonheads.com/classifieds/used-cars/...
I don't know the car or seller but with those miles it looks good value.
Edited by Fishy Dave on Thursday 16th July 08:29
Back in the middle of June when trackdays resumed I booked an afternoon at Castle Combe with friends.
I left feeling disappointed, the car wasn't handling as sweetly as before and I really struggled with high oil and water temperatures. I rarely had anyone on track at a similar speed (just the one Honda in the video) and it's those little battles that are most fun.
Whilst the hood vent had made a difference on the road the temperatures on track were worse than ever, what had gone wrong? Once home I had a poke around and am tackling the problem in a few ways:
1. I had opened holes in the 'shroud' to let in cooler air to the stock air filters, this is a well known modification in the States. I realised in doing this I was giving an easy route for high pressure air entering the front grille area to bypass the radiator/oil cooler. I closed the holes back up again.
2. In order for air to pass through the oil cooler, a/c condenser and radiator layers it relies on a pressure differential to work effectively. As above, high pressure air is driven in the front grille and also from below, with low pressure partly created by the lower air dam. Mine was looking very worn out where it scrapes on the ground.
3. Time to clean the A/C condensor again. I first did this two years ago, but these cars seem to hoover up all sorts of dirt and small stones. I bent an air hose attachment to 90 degrees and spent the best part of two hours trying to clear the debris by blasting air from the rear forwards, this alone should make quite a difference.
4. Using self adhesive draft excluder foam I blocked holes between the shroud and each of the three coolers, to remove easy escape routes for cooling air.
5. I drilled holes in the fan cover/frame. This will reduce its effectiveness in traffic, but will allow an easier escape path for air exiting the rads.
Before:
After, see holes at right of pic:
6. Change the Dexcool antifreeze mix, flushed it and then re-filled with Redline Water Wetter and Distilled water.
7. I ordered some ARC Cool Fin and some generic allow heat sink and suitable adhesive. My 'Base model doesn't come with any transmission cooler and whilst I'm not going to pretend this is any kind of substitute every degree helps. The Cool Fin is flexible so I attached some pieces to the gearbox and diff casing.
I have a 240v sump heating pad to pre-heat the oil in cooler weather, so around this I cut and bonded the heatsink to the flat sump bottom.
Hoping they won't hit the ground
I think the sump fins could be effective, the ARC cool fin stuff was expensive and will probably have a negligible effect honestly. I'm all for a bit of experimenting and losing a degree of heat here and there.
I left feeling disappointed, the car wasn't handling as sweetly as before and I really struggled with high oil and water temperatures. I rarely had anyone on track at a similar speed (just the one Honda in the video) and it's those little battles that are most fun.
Whilst the hood vent had made a difference on the road the temperatures on track were worse than ever, what had gone wrong? Once home I had a poke around and am tackling the problem in a few ways:
1. I had opened holes in the 'shroud' to let in cooler air to the stock air filters, this is a well known modification in the States. I realised in doing this I was giving an easy route for high pressure air entering the front grille area to bypass the radiator/oil cooler. I closed the holes back up again.
2. In order for air to pass through the oil cooler, a/c condenser and radiator layers it relies on a pressure differential to work effectively. As above, high pressure air is driven in the front grille and also from below, with low pressure partly created by the lower air dam. Mine was looking very worn out where it scrapes on the ground.
3. Time to clean the A/C condensor again. I first did this two years ago, but these cars seem to hoover up all sorts of dirt and small stones. I bent an air hose attachment to 90 degrees and spent the best part of two hours trying to clear the debris by blasting air from the rear forwards, this alone should make quite a difference.
4. Using self adhesive draft excluder foam I blocked holes between the shroud and each of the three coolers, to remove easy escape routes for cooling air.
5. I drilled holes in the fan cover/frame. This will reduce its effectiveness in traffic, but will allow an easier escape path for air exiting the rads.
Before:
After, see holes at right of pic:
6. Change the Dexcool antifreeze mix, flushed it and then re-filled with Redline Water Wetter and Distilled water.
7. I ordered some ARC Cool Fin and some generic allow heat sink and suitable adhesive. My 'Base model doesn't come with any transmission cooler and whilst I'm not going to pretend this is any kind of substitute every degree helps. The Cool Fin is flexible so I attached some pieces to the gearbox and diff casing.
I have a 240v sump heating pad to pre-heat the oil in cooler weather, so around this I cut and bonded the heatsink to the flat sump bottom.
Hoping they won't hit the ground
I think the sump fins could be effective, the ARC cool fin stuff was expensive and will probably have a negligible effect honestly. I'm all for a bit of experimenting and losing a degree of heat here and there.
Edited by Fishy Dave on Tuesday 25th August 10:34
I admire your attention to detail and some home made modifications in your approach. I remember chasing cooler temps on my old TVR in a similar fashion and water wetter was a great little easy addition! Thought it would be snake oil but definitely helped.
I had thought with the Vettes being run in the USA and in many in the Middle East they would be fine with temperatures.
I had thought with the Vettes being run in the USA and in many in the Middle East they would be fine with temperatures.
I reckon you could prob cut up the heat sinks and get more on the trans, and like you, I think lots of little bits would add up. Even if it's only a degree or two it could be enough to bring it to a point where the stock cooling is effective again.
Plus heatsinks, and thermal wraps just look cool.
Plus heatsinks, and thermal wraps just look cool.
Fishy Dave said:
Mr Tidy said:
That looks great OP, but I hope you didn't spend too long in Castle Combe village!
They don't seem to like brightly coloured cars in their villages.
https://uk.news.yahoo.com/ugly-yellow-blamed-for-r...
They probably wouldn't be too keen on a red LHD V8 Corvette.
Thanks, I sneaked through with the exhaust in quiet mode and switched off when snapping the photos. They don't seem to like brightly coloured cars in their villages.
https://uk.news.yahoo.com/ugly-yellow-blamed-for-r...
They probably wouldn't be too keen on a red LHD V8 Corvette.
I remember that yellow Corsa news, looks like it wasn't Castle Combe though.
Anyway, that, and the car aide, huge congratulations to you both on Austin's arrival. Parenthood in your 40's is fine. Provided they sleep perfectly, behave well, never get ill... oh. Bugger. I've been knackered since 2014. You get used to it.
My stickers arrived for Time Attack, it's a good job the Vette is a large car as this lot would fully wrap a Caterham!! I'm thinking of having a simple vinyl livery applied before adding these stickers. My first round isn't until 11th October at Snetterton so I've got some time yet.
To get in to the car you squeeze a hidden rubber pad, but the passenger side has sometimes required a couple of presses before those unfamiliar with this method could get in (some might say this is an advantage). The switches are so cheap at just £25 for the pair delivered it seemed silly not to change them. I still can't get used to how good value genuine Corvette parts are. Some parts are five or even ten times cheaper than Mazda want for my RX-8!
The switches took 5 minutes to fit, taking longer for me to find the correct torx bit than swapping them over. It's made an immediate improvement, just a light squeeze needed now.
I've had these frame protectors for a couple of years, finally got around to fitting them. It's neatened the frame up if nothing else.
The cable tie is just to hold the cover in place whilst the glue is drying.
The three of us attended Corvette Club meetings at Mollies Diner since lockdown, a friendly crowd, decent Covid precautions and good food too. https://www.molliesmotel.com/
The final piece of safety kit needed to compete in Time Attack was a handheld extinguisher. i bought a quick release mount from ebay and mounted it on the harness bar. In the event of a crash the extra weight would put extra strain on the bar, but less than if I had a passenger. The ebay mount is well made but has enough play that it rattles, so have added some thin rubber.
As the final Time Attack round at Donington on 15th November (my Birthday!) includes night stages I upgraded my fog lights (which I've used once only) with LED headlight bulbs. They are much brighter, but how on earth can they make any money on these at £7.50 for the pair delivered?!
One of the rear LED bulbs had failed and another had started to lose a few diodes, so time to upgrade these too: https://www.autobulbsdirect.co.uk/3157-twenty20-cr...
They are relatively pricey, but appear good quality and brighter in both tail and brake light applications than those I used before.
Finally, since fitting the Corbeau Evolution X seats last year I've never been happy at how high I sit. I could gain 20mm by ditching the sliders, but I like others to be able to drive my car comfortably. I removed the Corbeau subframes and took them to a local welder. £20 later and he'd removed 10mm from the rear mounting points, increasing the rake and lowering my head height. Better, but still not as low as I'd like, but I'll live with it now.
New track tyres are needed, the AD08R I bought 18 months ago have been brilliant and covered many road and track miles, but are well passed their best. I have just entered a round of Super Lap Scotland on 13th September at Knockhill. http://www.superlapscotland.co.uk/
It's similar to Time Attack, which is best described as qualifying sessions, with multiple cars on track at once, split by power to weight classes, all trying to set their fastest lap. It's going to be a long old drive up there, but I've been meaning to try the circuit out for years. Once complete it only leaves me to drive Lydden Hill and that's all the mainland UK tracks completed.
To get in to the car you squeeze a hidden rubber pad, but the passenger side has sometimes required a couple of presses before those unfamiliar with this method could get in (some might say this is an advantage). The switches are so cheap at just £25 for the pair delivered it seemed silly not to change them. I still can't get used to how good value genuine Corvette parts are. Some parts are five or even ten times cheaper than Mazda want for my RX-8!
The switches took 5 minutes to fit, taking longer for me to find the correct torx bit than swapping them over. It's made an immediate improvement, just a light squeeze needed now.
I've had these frame protectors for a couple of years, finally got around to fitting them. It's neatened the frame up if nothing else.
The cable tie is just to hold the cover in place whilst the glue is drying.
The three of us attended Corvette Club meetings at Mollies Diner since lockdown, a friendly crowd, decent Covid precautions and good food too. https://www.molliesmotel.com/
The final piece of safety kit needed to compete in Time Attack was a handheld extinguisher. i bought a quick release mount from ebay and mounted it on the harness bar. In the event of a crash the extra weight would put extra strain on the bar, but less than if I had a passenger. The ebay mount is well made but has enough play that it rattles, so have added some thin rubber.
As the final Time Attack round at Donington on 15th November (my Birthday!) includes night stages I upgraded my fog lights (which I've used once only) with LED headlight bulbs. They are much brighter, but how on earth can they make any money on these at £7.50 for the pair delivered?!
One of the rear LED bulbs had failed and another had started to lose a few diodes, so time to upgrade these too: https://www.autobulbsdirect.co.uk/3157-twenty20-cr...
They are relatively pricey, but appear good quality and brighter in both tail and brake light applications than those I used before.
Finally, since fitting the Corbeau Evolution X seats last year I've never been happy at how high I sit. I could gain 20mm by ditching the sliders, but I like others to be able to drive my car comfortably. I removed the Corbeau subframes and took them to a local welder. £20 later and he'd removed 10mm from the rear mounting points, increasing the rake and lowering my head height. Better, but still not as low as I'd like, but I'll live with it now.
New track tyres are needed, the AD08R I bought 18 months ago have been brilliant and covered many road and track miles, but are well passed their best. I have just entered a round of Super Lap Scotland on 13th September at Knockhill. http://www.superlapscotland.co.uk/
It's similar to Time Attack, which is best described as qualifying sessions, with multiple cars on track at once, split by power to weight classes, all trying to set their fastest lap. It's going to be a long old drive up there, but I've been meaning to try the circuit out for years. Once complete it only leaves me to drive Lydden Hill and that's all the mainland UK tracks completed.
Edited by Fishy Dave on Tuesday 25th August 11:59
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