The £7700 Corvette C6
Discussion
Before the virus shut everything down I was able to get a few days of gentle driving in the week before the planned Snetterton trackday. It was frustrating have to trundle round on a gentle throttle everywhere whilst bedding in the diff. The drive up to Norfolk (from Wiltshire) showed about a 300rpm difference in top at motorway cruising speed, around 1950-2000rpm at 80mph, so hardly revving like crazy.
The organiser of this private trackday (Richard) was already at Thetford when I arrived, you get a decent class of car at a Travelodge.
Monday 9th March, time for the trackday. I had a number of guests, with family there, including my Dad who was driving, the Editor of the Corvette Club Magazine (Mark) and the first time I've met PHer and fellow C6 owner Mr Noisy (and son).
The day was dry, relatively warm and had low numbers of cars by design, perfect. Sometimes we wondered if there was a red flag, the track was that quiet, that is until two Corvettes chased round together!
First time there has been another Corvette C6 on track with me, both cars well matched despite their different specification and age of tyre. The gear ratios have really improved the driving experience for me, not sure of laps times to compare though. Richard (MrNoisy) has the Z51 pack on his C6, that has different ratios from the base model. The ratios of both cars seem broadly similar, only I was just using 5th on the back straight, whereas Richard could just stay in 4th. The gap from 4th to 5th appears larger than those between the first 4 gears.
The only other footage I have from Snetterton with the old ratios was when I was bedding in new pads and new tyres, as you'll see at the beginning of this clip:
The Corvette covered many laps, getting through three, large tankfuls of petrol over the day, with three of us driving it. With an hour to go I was black flagged, a good job too as I was leaking oil, two types! After I'd left the garage my Dad noticed spots on the garage floor and alerting the Marshals. It looks like the aux belt had snapped and got itself wedged behind the main pulley, pressing against the front main oil seal, losing a litre in the process!
No great damage done but a lot of mess and I need to investigate why the belt has twice broken on track. The car got me home, with no further oil loss. Despite the ending it was one of the best trackdays I've done in years.
Once cleaned up on the ramp I discovered a small leak from one of the power steering unions into the rack (the hose rear most in the photo below). It was very difficult to get to, but a tenth of a turn later and it was nipped up and stopped the leak.
I have ordered a new front main oil seal and will change it as a precaution, as I can see a small oil stain appearing now I've driven the car again since the clean up.
My wife had bought me a new, genuine GM front badge for my Christmas present (over £100!), so I changed that over before afternoon tea at Bowood House.
That brings us up to date, with no further driving likely for a while now I'm working from home.
The organiser of this private trackday (Richard) was already at Thetford when I arrived, you get a decent class of car at a Travelodge.
Monday 9th March, time for the trackday. I had a number of guests, with family there, including my Dad who was driving, the Editor of the Corvette Club Magazine (Mark) and the first time I've met PHer and fellow C6 owner Mr Noisy (and son).
The day was dry, relatively warm and had low numbers of cars by design, perfect. Sometimes we wondered if there was a red flag, the track was that quiet, that is until two Corvettes chased round together!
First time there has been another Corvette C6 on track with me, both cars well matched despite their different specification and age of tyre. The gear ratios have really improved the driving experience for me, not sure of laps times to compare though. Richard (MrNoisy) has the Z51 pack on his C6, that has different ratios from the base model. The ratios of both cars seem broadly similar, only I was just using 5th on the back straight, whereas Richard could just stay in 4th. The gap from 4th to 5th appears larger than those between the first 4 gears.
The only other footage I have from Snetterton with the old ratios was when I was bedding in new pads and new tyres, as you'll see at the beginning of this clip:
The Corvette covered many laps, getting through three, large tankfuls of petrol over the day, with three of us driving it. With an hour to go I was black flagged, a good job too as I was leaking oil, two types! After I'd left the garage my Dad noticed spots on the garage floor and alerting the Marshals. It looks like the aux belt had snapped and got itself wedged behind the main pulley, pressing against the front main oil seal, losing a litre in the process!
No great damage done but a lot of mess and I need to investigate why the belt has twice broken on track. The car got me home, with no further oil loss. Despite the ending it was one of the best trackdays I've done in years.
Once cleaned up on the ramp I discovered a small leak from one of the power steering unions into the rack (the hose rear most in the photo below). It was very difficult to get to, but a tenth of a turn later and it was nipped up and stopped the leak.
I have ordered a new front main oil seal and will change it as a precaution, as I can see a small oil stain appearing now I've driven the car again since the clean up.
My wife had bought me a new, genuine GM front badge for my Christmas present (over £100!), so I changed that over before afternoon tea at Bowood House.
That brings us up to date, with no further driving likely for a while now I'm working from home.
Edited by Fishy Dave on Thursday 11th June 17:19
Love reading your adventures, particularly in a car I lust after! I am a big fan of high mileage cars, particularly when its something sports/super car like that are usually tucked up in garages and people preserving the miles for one reason or another. My Aston has done decent miles and wears a few of the scars from adventures and to me it adds to the character where I can recall some of the adventures involved.
Still yet to find a decent C6 for reasonable money. Once this whole CV thing has blown over I am tempted to embark on a similar route to yourself to add to some of the history; it adds a real dimension.
Still yet to find a decent C6 for reasonable money. Once this whole CV thing has blown over I am tempted to embark on a similar route to yourself to add to some of the history; it adds a real dimension.
Thanks guys, glad someone still reads this. 
It was time to replace the front main oil seal, after the shredded Air Con belt became jammed at Snetterton last month. It's a bit of a job to get to the seal, fortunately (?!) I've become familiar with removing the steering rack and moving everything else out the way to get to the Harmonic Balancer/main pulley (henceforth HB).
In addition to changing the oil seal I will investigate why the belt has now jumped off twice in the last 6 months whilst on track and also relocate the Mocal power steering cooler I fitted last season, as it's in the way of air flow behind the radiator.
I had two of these little chaps looking on.
I bought one of these pullers from ebay as the holes in the HB are imperial (Power Bond Race).
With the steering rack moved to one side I could get at the pulley.
Running a metal ruler from the HB to the A/C pulley I could see that the HB was about 1.5mm too far forwards, compared to the A/C compressor. Not a lot, but with the engine at 6500rpm on track it is probably enough to bounce the belt off.
I removed the reusable ARP bolt and fitted the puller, it worked perfectly.
Yup, that's definitely where the oil was coming from. The indent in the crank end is from where I drilled and pinned the crank and balancer together last year, it reduces the chances of the pulley spinning on the shaft.
You can see parts of the old belt still jammed into the seal!
At this point I was scratching my head why the balancer should be sticking out a touch more than it should, I had after all torqued the bolt correctly last year and 240lb/ft is plenty to have fully pressed it home. After hours of googling I found the answer. It was the combination of the Melling high volume oil pump (which is wider) and the Powerbond Harmonic Balancer (different shape to standard) that accounts for the difference.
This left me with a few options:
1. Live with it, but risk losing another belt. Considering the first belt took out the power steering hose and the second caused an oil leak I didn't fancy this one.
2. Live with it but remove the AC belt anytime I did a trackday. It's a bit of a hassle doing this each time and on a summers trackday I might actually want working A/C.
3. Replace either the oil pump or the HB. As both were new last year I didn't fancy the wait or the expense, although I should have bought an underdrive pulley in the first place. having said that most underdrive pulleys don't slow down the AC belt, only the main serpentine one.
4. Modify the existing HB by removing a small amount of material from the 'snout' so it fits further towards the engine block, snug against the oil pump.
The correct way of carrying out option 4 would be to take it to a local engineering company, but with almost everywhere shut down and this hardly being essential I thought I'd risk having a go myself. At this point all precision engineers might want to look away.
The sum total of my tools being an angle grinder with metal grinding disk, some hand files, various straight edges and an old Black and Decker Workmate.
Fortunately the snout has a chamfered edge of exactly the amount I aimed to remove.
With careful grinding it became this.
Some gentle filing and it was as flat as I could make it with hand tools.
Having the lift makes these jobs so much easier. Lifting to 1 metre is just the right height for sitting or kneeling.
With the balancer fitted back in place the belt run looks perfectly true. I bought a Continental belt a couple of mm shorter, just to put the tensioner in a slightly different place. Time will tell if this makes a difference.
Next up was to look at relocating the power steering cooler. To recap, my base model C6 Coupe has a very basic power steering cooler, consisting of a twirly looking bit of alloy pipe. The power steering pump and rack both got cooked with the effort of shifting sticky 265 profile track tyres, an expensive lesson. Instead of opting for the GM Z51 spec cooler (a similar bit of allow pipe with a few fins attached) I went for a small Mocal oil cooler that I fitted in the stock location. This was directly behind the radiator fan, not ideal as it blocks airflow exiting the rear of the radiator. I refitted the stock cooler and extended hoses to locate the Mocal behind the left side fog light void/in front of the wheel well. This location only gets minimal air flow and I didn't want to lose the front fog lights at this point, so I opted for a switcheable 9cm puller fan instead. The fan draws its power from the under hood light. The cooler is on the low pressure side of the steering, so oil hose and stainless hose clips do the job. You can see the basic 'cooler' in the lower background of the photo, attached to the subframe.
I didn't finish until 22:00 on Sunday night (hence no finished engine bay photos), but drove it in to work yesterday and treated it to a wash, before driving home again with the roof off. No oil leak, so far so good.
I am still hoping that I can compete in the final round of Time Attack of the year at Snetterton in October and have booked a Donington trackday in November, but who knows?
It was time to replace the front main oil seal, after the shredded Air Con belt became jammed at Snetterton last month. It's a bit of a job to get to the seal, fortunately (?!) I've become familiar with removing the steering rack and moving everything else out the way to get to the Harmonic Balancer/main pulley (henceforth HB).
In addition to changing the oil seal I will investigate why the belt has now jumped off twice in the last 6 months whilst on track and also relocate the Mocal power steering cooler I fitted last season, as it's in the way of air flow behind the radiator.
I had two of these little chaps looking on.
I bought one of these pullers from ebay as the holes in the HB are imperial (Power Bond Race).
With the steering rack moved to one side I could get at the pulley.
Running a metal ruler from the HB to the A/C pulley I could see that the HB was about 1.5mm too far forwards, compared to the A/C compressor. Not a lot, but with the engine at 6500rpm on track it is probably enough to bounce the belt off.
I removed the reusable ARP bolt and fitted the puller, it worked perfectly.
Yup, that's definitely where the oil was coming from. The indent in the crank end is from where I drilled and pinned the crank and balancer together last year, it reduces the chances of the pulley spinning on the shaft.
You can see parts of the old belt still jammed into the seal!
At this point I was scratching my head why the balancer should be sticking out a touch more than it should, I had after all torqued the bolt correctly last year and 240lb/ft is plenty to have fully pressed it home. After hours of googling I found the answer. It was the combination of the Melling high volume oil pump (which is wider) and the Powerbond Harmonic Balancer (different shape to standard) that accounts for the difference.
This left me with a few options:
1. Live with it, but risk losing another belt. Considering the first belt took out the power steering hose and the second caused an oil leak I didn't fancy this one.
2. Live with it but remove the AC belt anytime I did a trackday. It's a bit of a hassle doing this each time and on a summers trackday I might actually want working A/C.
3. Replace either the oil pump or the HB. As both were new last year I didn't fancy the wait or the expense, although I should have bought an underdrive pulley in the first place. having said that most underdrive pulleys don't slow down the AC belt, only the main serpentine one.
4. Modify the existing HB by removing a small amount of material from the 'snout' so it fits further towards the engine block, snug against the oil pump.
The correct way of carrying out option 4 would be to take it to a local engineering company, but with almost everywhere shut down and this hardly being essential I thought I'd risk having a go myself. At this point all precision engineers might want to look away.
The sum total of my tools being an angle grinder with metal grinding disk, some hand files, various straight edges and an old Black and Decker Workmate.
Fortunately the snout has a chamfered edge of exactly the amount I aimed to remove.
With careful grinding it became this.
Some gentle filing and it was as flat as I could make it with hand tools.
Having the lift makes these jobs so much easier. Lifting to 1 metre is just the right height for sitting or kneeling.
With the balancer fitted back in place the belt run looks perfectly true. I bought a Continental belt a couple of mm shorter, just to put the tensioner in a slightly different place. Time will tell if this makes a difference.
Next up was to look at relocating the power steering cooler. To recap, my base model C6 Coupe has a very basic power steering cooler, consisting of a twirly looking bit of alloy pipe. The power steering pump and rack both got cooked with the effort of shifting sticky 265 profile track tyres, an expensive lesson. Instead of opting for the GM Z51 spec cooler (a similar bit of allow pipe with a few fins attached) I went for a small Mocal oil cooler that I fitted in the stock location. This was directly behind the radiator fan, not ideal as it blocks airflow exiting the rear of the radiator. I refitted the stock cooler and extended hoses to locate the Mocal behind the left side fog light void/in front of the wheel well. This location only gets minimal air flow and I didn't want to lose the front fog lights at this point, so I opted for a switcheable 9cm puller fan instead. The fan draws its power from the under hood light. The cooler is on the low pressure side of the steering, so oil hose and stainless hose clips do the job. You can see the basic 'cooler' in the lower background of the photo, attached to the subframe.
I didn't finish until 22:00 on Sunday night (hence no finished engine bay photos), but drove it in to work yesterday and treated it to a wash, before driving home again with the roof off. No oil leak, so far so good.
I am still hoping that I can compete in the final round of Time Attack of the year at Snetterton in October and have booked a Donington trackday in November, but who knows?
Edited by Fishy Dave on Tuesday 7th April 14:39
5harp3y said:
99t said:
Great thread and a lovely car 
Silly question though, isn't that seal you've removed to keep heat and engine bay fumes out of the HVAC system, the inlet to which appears to be just to the rear of the seal?
yup Silly question though, isn't that seal you've removed to keep heat and engine bay fumes out of the HVAC system, the inlet to which appears to be just to the rear of the seal?
seems like a bit of a sticking plaster fix
Looking at some basic wind tunnel diagrams it looked likely that removing the seal would actually make heat egress worse at high speeds. Thanks.Edited by Fishy Dave on Thursday 9th April 12:44
The C6 made a few Covid restricted supermarket trips, its spacious boot helping to swallow even the largest of 'big shops' (not the small trolley load pictured).
I had ordered a pair of Corbeau harness back in January, but with a delay for shortage of parts, then the virus shutting things down I decided to cancel the order in early May. In their place I ordered a 4 point Schroth anti-submarine harness (Profi 2 asm flexi) for the drivers side only. Why only a 4 point? The Corbeau seats don't have a harness slot in the base, nor do they recommend modifying them. A 4 point can be safe provided the fitment and tightness of lap straps is correct, this model is FIA approved and can be used with a HANS.
https://www.schroth.com/en/segments/racing/product...
Their anti-submarine tech: https://www.schroth.com/en/segments/tuning/service...
Big news in the Fishy household, our first (and only) child was born on the 13th of May. We've named him Austin, after the trackday we enjoyed as part of the whole Corvette buying trip.
We bought a car seat that is suitable for both Isofix and the Corbeau's, so he'll get to experience the Vette at some stage.
This last week I was able to enjoy a decent drive across Salisbury Plain then across to Dorset, Zig Zag Hill and the Deverill Hills. Brilliant to get out, roof off in the sunshine with quiet roads.
I've been keeping an eye on intake air temperatures on the Android head unit. After parking up for just a few minutes the temps would be above 140F and take at least 10 minutes of driving before they would drop to within 20 degrees of ambient. The stock LS2 intake is pretty good but draws its air from the engine bay; safe from flooding but not good for heat and therefore power. The stock tune pulls timing if the air temps or coolant temps rise just a little beyond normal running temperatures, losing power: https://www.corvetteforum.com/forums/c6-tech-perfo...
As I try to run the car on a sensible budget I opened up the bottom of the shroud a little to allow more air from the grille area. This has helped in how fast the IAT drops now, taking around 4 or 5 minutes of driving at A road speeds to reach within 10 degrees of ambient.
Coolant temps do reach 235F on track, at which point it is pulling a fair bit of timing, this despite fresh coolant and a decent, all alloy radiator. I have ordered new rubber front skirts from the States, as these help direct air up and into the bottom feeding radiator inlet and brake cooling ducts (the old ones are pretty worn out from striking the ground).
Lastly, the measure I have agonised over for months, a bonnet/hood vent. These are pretty common in the modified or track Corvette community, but I've never really seen a design I'm happy with. They are usually in black, held on with rivets and look a bit Max Power for my liking, however functional these aftermarket items are. The CFD image of the C6R is useful in understanding the low pressure areas.
Many owners in the States have opted for a central vent from a Camaro. I like the thought of a factory finish but am really not keen on the look, or the positioning so far towards the windscreen, getting closer towards a high pressure area.
Reading this guide: https://racelouvers.com/content/hood-louver-guide.... it says among many other recommendations:
[i]Wide louvers always outperform narrow extractors.
Best Hood Louver location is centered 2" behind radiator.[/i]
I removed the bonnet liner, frustratingly it has a support in just about the optimum place for a vent (a Corvette rad is actually quite far back from the nose of the car), so I would need to locate any aperture just behind this brace.
Next I looked at the BMW M4 GTS and new M2 CS models, both of which have a single, wide opening just behind the Radiator.
The M2CS isn't actually available right now, so I have no way of seeing a vent or measuring it, but with a bit of work I've managed to order the part for less than £50 and it's on its way from Germany right now. I've left the metal grill for now as this is an extra £150.
When it arrives I'll make a final decision, but I really don't want to spoil the look of my car! Not sure fitting a BMW part will go down well with the purists, but I hope it will be functional (reduced running temps and less lift at speed) and if I paint it Victory Red to match it won't stand out too much?
I have booked a trackday at Castle Combe on Monday 15th June to find out if it makes any improvement.
I had ordered a pair of Corbeau harness back in January, but with a delay for shortage of parts, then the virus shutting things down I decided to cancel the order in early May. In their place I ordered a 4 point Schroth anti-submarine harness (Profi 2 asm flexi) for the drivers side only. Why only a 4 point? The Corbeau seats don't have a harness slot in the base, nor do they recommend modifying them. A 4 point can be safe provided the fitment and tightness of lap straps is correct, this model is FIA approved and can be used with a HANS.
https://www.schroth.com/en/segments/racing/product...
Their anti-submarine tech: https://www.schroth.com/en/segments/tuning/service...
Big news in the Fishy household, our first (and only) child was born on the 13th of May. We've named him Austin, after the trackday we enjoyed as part of the whole Corvette buying trip.
We bought a car seat that is suitable for both Isofix and the Corbeau's, so he'll get to experience the Vette at some stage.
This last week I was able to enjoy a decent drive across Salisbury Plain then across to Dorset, Zig Zag Hill and the Deverill Hills. Brilliant to get out, roof off in the sunshine with quiet roads.
I've been keeping an eye on intake air temperatures on the Android head unit. After parking up for just a few minutes the temps would be above 140F and take at least 10 minutes of driving before they would drop to within 20 degrees of ambient. The stock LS2 intake is pretty good but draws its air from the engine bay; safe from flooding but not good for heat and therefore power. The stock tune pulls timing if the air temps or coolant temps rise just a little beyond normal running temperatures, losing power: https://www.corvetteforum.com/forums/c6-tech-perfo...
As I try to run the car on a sensible budget I opened up the bottom of the shroud a little to allow more air from the grille area. This has helped in how fast the IAT drops now, taking around 4 or 5 minutes of driving at A road speeds to reach within 10 degrees of ambient.
Coolant temps do reach 235F on track, at which point it is pulling a fair bit of timing, this despite fresh coolant and a decent, all alloy radiator. I have ordered new rubber front skirts from the States, as these help direct air up and into the bottom feeding radiator inlet and brake cooling ducts (the old ones are pretty worn out from striking the ground).
Lastly, the measure I have agonised over for months, a bonnet/hood vent. These are pretty common in the modified or track Corvette community, but I've never really seen a design I'm happy with. They are usually in black, held on with rivets and look a bit Max Power for my liking, however functional these aftermarket items are. The CFD image of the C6R is useful in understanding the low pressure areas.
Many owners in the States have opted for a central vent from a Camaro. I like the thought of a factory finish but am really not keen on the look, or the positioning so far towards the windscreen, getting closer towards a high pressure area.
Reading this guide: https://racelouvers.com/content/hood-louver-guide.... it says among many other recommendations:
[i]Wide louvers always outperform narrow extractors.
Best Hood Louver location is centered 2" behind radiator.[/i]
I removed the bonnet liner, frustratingly it has a support in just about the optimum place for a vent (a Corvette rad is actually quite far back from the nose of the car), so I would need to locate any aperture just behind this brace.
Next I looked at the BMW M4 GTS and new M2 CS models, both of which have a single, wide opening just behind the Radiator.
The M2CS isn't actually available right now, so I have no way of seeing a vent or measuring it, but with a bit of work I've managed to order the part for less than £50 and it's on its way from Germany right now. I've left the metal grill for now as this is an extra £150.
When it arrives I'll make a final decision, but I really don't want to spoil the look of my car! Not sure fitting a BMW part will go down well with the purists, but I hope it will be functional (reduced running temps and less lift at speed) and if I paint it Victory Red to match it won't stand out too much?
I have booked a trackday at Castle Combe on Monday 15th June to find out if it makes any improvement.
Edited by Fishy Dave on Tuesday 26th May 18:12
Fishy Dave said:
Not sure fitting a BMW part will go down well with the purists, but I hope it will be functional (reduced running temps and less lift at speed) and if I paint it Victory Red to match it won't stand out too much?
Congrats on the new sproglet, he will be passing you wrenches in no time! Plus the V8 is the best method of getting a kid to sleep I have ever come across, like you needed any more reasons to take your car for a spin!As to the above quote, it's your car and corvettes are traditionally quite modified by their owners anyway - I would class any functional improvement as a win and the GM engineers would be behind you - they had budgets restricting what they coud implement, whereas you are free.
As long as you put locktight on the HB crank bolt I can't see an issue with it coming undone, as long as the belt tension and deflection is set to factory spec.
Brilliant updates, always look forward to reading them.
F1natic said:
Congrats on the new sproglet, he will be passing you wrenches in no time! Plus the V8 is the best method of getting a kid to sleep I have ever come across, like you needed any more reasons to take your car for a spin!
As to the above quote, it's your car and corvettes are traditionally quite modified by their owners anyway - I would class any functional improvement as a win and the GM engineers would be behind you - they had budgets restricting what they coud implement, whereas you are free.
As long as you put locktight on the HB crank bolt I can't see an issue with it coming undone, as long as the belt tension and deflection is set to factory spec.
Brilliant updates, always look forward to reading them.
Thank you. My wife has been saying for some time she'll be glad when Austin is older so she won't have to respond to the requests for help when I'm under the car. His little hands should be just perfect for fiddly jobs As to the above quote, it's your car and corvettes are traditionally quite modified by their owners anyway - I would class any functional improvement as a win and the GM engineers would be behind you - they had budgets restricting what they coud implement, whereas you are free.
As long as you put locktight on the HB crank bolt I can't see an issue with it coming undone, as long as the belt tension and deflection is set to factory spec.
Brilliant updates, always look forward to reading them.
. He's been hearing the V8 from the womb, so we're hoping it's a familiar sound now. You are right of course about the modifications, I've had a call from BMW Bath to say that the M2 CS scoop is in, much faster delivery than we were expecting.
The HB is torqued up nicely with the ARP bolt and loctite so it should go anywhere and so far the AC belt is staying put. I had the system re-gassed yesterday so it's icy cold rather than just cool.
Cheers, Dave
MrNoisy said:
Great day at Snett, I'm glad I could prove scientifically that red cars are indeed faster than silver ones. Honestly one of the best trackdays i've attended, looking forward to Donington later in the year for sure.
Congrats to you all on the new arrival!
I really enjoyed the day too, I'd say the cars were pretty well matched taking into account the different gearing, modifications, tyres and confidence/showing off. Congrats to you all on the new arrival!
Are there any other Corvette's up for attending a private trackday at Donington on Monday November 2nd?
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