180° Crossover Equal Length Manifolds

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Most TVR owners will be familiar with Clive Ford’s stainless master pieces in the form of his popular manifold Y Piece. Last year Clive surpassed himself and created a tuned crossover manifold system, the same design as seen on the legendary Le Mans winning Ford GT40 that somehow fits under the bonnet of a Griff.

So what is the point of a crossover manifold? The issue with a conventional 4-1 exhaust header is the separation between exhaust impulses. With a 90° (cross plane) crankshaft 2 exhaust pulses exit through the collector at the same time. A crossover manifold pairs the correct cylinders that fire 180° degrees apart in their firing are paired together, maximizing scavenging. When one cylinder is on the compression stroke, the other is on the exhaust stroke resulting in a constant flow, thus creating equally spaced exhaust pulses.The result is similar to that of a 180° (flat plane) crankshaft with four evenly spaced exhaust pulses in each header.

I had managed to resist the temptation of Clive’s latest masterpiece until I bumped into fellow Griff owner Peter Billington at the Griff Growl last year. Peter has a immaculate, sensibly modified Griffith and had just completed fitting the crossover manifold system. Peter very kindly offered to take me out for a spin in his to demonstrate the new manifolds and I was sold. The sound was incredible, a cross between a RV8 and Cerebra with the howl of a GT40 higher up the rev range…. epic! A few weeks later Clive received an order.

I am still running the OEM Lucas 14CUX ECU on my Griffith. I asked Clive to build the manifolds with two narrowband lambda sensor bosses (one per bank)  for the 14CUX and two wideband lambda sensor bosses for a future expansion (aftermarket ECU). I also asked for a wideband lambda sensor to fitted where both banks merge to allow me to run an AFR gauge at a later date.

Running the 14CUX with this system does pose an issue in that the lambda sensors in standard configuration read from  cylinders 2,4,6 and 8, and 1,3,5 and 7. With the crossover manifolds fitted the sensors read cylinders 1, 4, 6 and 7, and 2,3,5 and 8. The 14CUX is bank fired so to correct this it is a simple case of extending the injector wiring so injector wires 3 and 5 are swapped for 4 and 6.

Changing manifolds on a TVR is always a time consuming job due to the lack of access to the bolts. 2 long evening later the manifolds were fitted. The water pipe to the radiator was rerouted underneath the chassis rail and I took the opportunity to fit a JE alternator bracket to replace the tensioner.

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First impressions are very good. The car seems to rev much more freely and the sound is epic. Below is a quick test on a cold day in February with new tyres so not going too mad. I will record a better video soon…

The car went to Dom at TVR Power for a service in March, while the car was in I asked him to put the car on the dyno for a power run to check the AFRs and also see what difference the manifolds made.

2016 Dyno Result

275.17BHP & 295.93ftlb at the wheels.

TVR Power dyno reads in wheel figures so I have converted to flywheel figures using the below site
http://www.mk5cortinaestate.co.uk/calculator4.php

BHP – 324BHP
Torque – 348ftlb

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2017 Dyno Result

274.52BHP & 301.77ftlb at the wheels.

BHP – 323BHP
Torque – 355ftlb

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Peak torque is up a bit but I am mainly impressed by the healthy increase in bottom end torque. The result is certainly promising but the car is running rich now so not really a fair comparison without a remap. There will certainly be more come with an adjustment on the fuelling and the addition of mapped ignition.

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Battery Relocation

TVR Battery relocation is always a fiercely debated subject. The standard location is in the passenger footwell along with the ECU and fusebox. Although some will argue that this is the best place, in the Griffith passenger leg room can be described as woeful at best. My second motivation for looking into relocation is to tidy up the mess in the footwell and to allow easier access to the fusebox and ECU.

Existing battery location
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The OEM battery is a standard lead acid type 072.

072 Battery Specifications
AH Value 70
CCA 570
Reserve Capacity 125
Length 261mm
Depth 175mm
Height 220mm
Weight 18.4 KG

A popular battery relocation option and one that a number of TVR owners have opted for over the years is to fit a single Odyssey PC925 battery in the boot of the car. Speaking to owners who have fitted this battery, all have been very pleased with the result long term and have not had any notable issues.

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Odyssey PC925 Specifications
AH Value 28
CCA 330
Reserve Cap 27
Length 168mm
Depth 179mm
Height 148mm
Weight 11.8 KG

Odyssey batteries are widely regarded as one of the best batteries available and have various advantages over traditional types of battery:

Cranking power – capable of providing engine cranking pulses in excess of 2250 amps for 5 seconds, double to triple that of equally sized conventional batteries
Longer service life – up to 10 years of service life
Longer cycle life – 70% longer cycle life than conventional deep cycle batteries
Faster recharge – The highest recharge efficiency of any sealed lead battery on the market, capable of 100% recharge in 4-6 hours.
Mounting flexibility – Non-spillable design, can be mounted on any side in any position except inverted.
Vibration resistance – Design protects against high impact shock and mechanical vibration, a common cause of premature battery failure.
Extreme temperature tolerant – Operating temperatures from -40°C to 45°C
Small footprint – flat plates made of 99.99% pure lead, not lead alloy. Pure lead plates can be made thinner.
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Relocating the battery in the boot is great from an accessibility point of view but the issue for me is the fact the battery is located next to the fuel tank. While I accept that you do not buy a TVR for its safety credentials, personally I am not entirely comfortable with potentially introducing additional risk if it can be otherwise avioded. The chassis of the Griffith does not extend much past the rear wheels which leaves the boot area of the car protected only by fibreglass in the event of a rear end shunt as can be seen in the picture below:

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In search of other solutions I turned the PistonHeads TVR community to see what other owners had done with theirs. As always lots of assistance and ideas came flooding in. I did see a number of Chimaera owners who had created a custom compartment behind one of the seats out of fibreglass which looks like a great solution. Unfortunately in the Griff I needed to retain access under the whale tail to access the bolts which secures it in place.

There was one suggestion from fellow Griff owner Frank (eff eff) who had done something I had not seen before. Frank had two smaller Odyssey batteries wired in parallel, one fitted behind each seat. What a liked about the design was not only were the batteries safely stored within the passenger compartment, away from the fuel tank, but the weight was evenly distributed.  I decided this was the solution for me so I contacted Frank who very kindly shared the specification of his install with me so I could replicate this in my car.

My solution, heavily based on Frank’s design is as follows:

2 x Odyssey PC680 wired in parallel (same voltage but double the AH value). This results slightly higher AH and CCA values and almost double the reserve capacity figure of the tried and tested single PC925 solution.

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Odyssey PC680 – Single
AH Value 16Ah
CCA 17
Reserve Cap 24mins
Length 184mm
Depth 79mm
Height 191mm
Weight 7KG

Odyssey PC680 – Double
AH Value 32Ah
CCA 340
Reserve Cap 48mins
Weight 14KG

Regarding the hold down kit, the official kit from Odyssey would not fit in the area behind the seats so I needed to source an alternative with a smaller foot print.

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After some searching on the internet I found a lightweight billet hold down kit from an American company called JPUSA. The hold down kit had a footprint only slightly larger that the PC680 battery itself.

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https://www.jhpusa.com/store/pc/viewPrd.asp?idproduct=6661&idcategory=128

I understand from owners of TVRs equipped with the PC925 battery that the battery must not be allowed to run flat (under 10.5v) as the battery cannot be revived. Running the battery flat is not normally an issue for me as generally the car is attached to a trickle charger when not in use. I have run my existing battery flat a couple of times down to my own stupidity (leaving lights on etc). Due to the reduced reserve capacity of the Odyssey batteries vs the OE 072 battery I decided it would be a good idea to fit a battery monitor in the form of Battery Brain. A Battery Brain is a compact battery monitoring device that continually monitors the battery charge. If the charge to drops below the minimum required level (11.8v) to start the vehicle, it disconnects the battery. Not only does this stop you getting stranded it also protects the battery from becoming fully discharged. I decided to purchase the battery brain with the IR remote disconnect fob just in case I need to leave the car for a long period of time I can remotely disconnect the battery after I have locked the car.

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http://www.batterybrain.co.uk

I asked Jody at Python Racing to complete the conversion while the car was in having its annual MOT completed. As per usual Jody did an excellent job and I am very pleased with the end result. I will arrange for the trimmer to fit an extended piece of carpet in the passenger footwell and possibly carpet over the batteries in the near future.

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I also purchased a new trickle charger for the car as part of this upgrade. I was unsure as to whether my Accumate trickle charger was compatible with AGM Gell batteries. To be on the safe side I purchased a new CTEK charger with an AGM battery mode.

Rear Brake upgrade

The rear brakes on my Griff were in need of some attention, I have had issues with intermittent binding over the last few years and as a result I managed to wear the pads down completely. The discs I believe are the originals from the factory and are heavily corroded so in need of replacement anyway.

As per usual I try to replace parts for upgraded items where I can so rather than OE I decided on a cheeky upgrade.

I already have the Alcon 4pot upgrade on the front of my Griff which I really like and fits under the 15″ OE wheel. The Alcon fill the front wheels nicely but the rears look a bit small now in comparison. After looking at various options and not wanting to upset the brake bias I decided to keep the original callipers and but go for bigger discs. My logic behind this is the brake bias was fine with OE front and rear, bias was fine with the 4pots on the front and OE on the back, so a larger disc on the back with OE callipers will bring this a little further back to OE so bias still fine. In theory!

I decided on the the Reyland 300mm rotor upgrade. I know a number of other owners who have had this fitted and are happy with it. It is also the same kit the Cossie boys use on their cars and there did not seem to be any complaints on their forums. I quick chat with Martin at Reyland and the kit was ordered.

http://www.reyland.co.uk/tvr/

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I also decided to get the brake callipers refurbished and the brake build changed. Rather than sending them to one of the usual companies that specialise in brake calliper refurbishment I opted to use a TVR local specialist with experience in this area. Jody from Jody at Python Racing offers this service and has done a number of calliper rebuilds for various TVRs. I had asked him to match as closely as possible the original grey finish on Alcon 4 pot brakes I have fitted to the front.

http://www.pythonracing.co.uk

Very impressed with the service and the end result….

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The kit fitted:

Rear:
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Front (existing Alcon kit):
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Snetterton 300 Track Day

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Another Snetterton track day organised by fellow TVR Pistonheaders. One of my favourite tracks as it is less than 2 hours away from where I live and it suits the Griff being a power track with long straights.

The circuit for the track day was the full 3mile ‘300’ circuit which includes 2 fast straights and a number of more technical areas.
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The noise limit for the day was 105dB static. Last year I just sneaked through the limit without the need for any additional cans. This year the same, the car was measured as 104dB much to the surprise of the MSV staff. On track unfortunately I I was black flagged as I breached the driveway noise limit and was required to don the ACT bolt on silencers.

The weather forecast was grim but the rain did not come in the quantity that was forecast so for the most part the track was dry. The TVR performed impeccably.

As per usual my trusty GoPro was on hand, unfortunately MSV deemed that the official 3M GoPro mount was no longer allowed for trackdays and all cameras needed to be mechanically mounted so I was not allowed to run with the camera on the front of the car.

I was also running Harry’s Lap Timer app on my iPhone, not for competitive lap timing as this is not allowed but for video telemetry overlay on my personal videos.

I have also invested in a Racelogic VBox Sport to use with Harry’s Lap Timer as the iPhone internal 1Hz GPS sensor proved did not seem to adequately keep up with the video before. The Racelogic VBox has a 20hz GPS sensor and pair with the iPhone using bluetooth. You can see it Gaffer taped to the dashboard in the video.

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My best lap of the day was 2:24.66 at an average speed of 73.8MPH which I was happy with.

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TVR Power Dyno Run

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I booked the Griff in with Powers Performance (TVR Power) for a dyno run following my last visit to the drag strip for PH Sunday service. My 1/4 PB is 13.202 a couple of years ago, I have since changed the standard cam for a TVR Power 885 cam and the road tyres have been swapped for AD08Rs.

Sunday service was great fun but I could not get any faster than a 13.5 and my terminal speed was down from 107 to 104. My assumption was the car had lost a bit of power somewhere so I booked the car in with Jason at TVR Power.

To my suprise the car was up from 242.8BHP on the original TVR435 cam to 275.1BHP on the TVR Power 885 cam. Torque also looking more healthy up from 278 to 295. Clearly no horses have bolted the stable so clearly down to the driver :-/ perhaps I have lost some driver XP

TVR Power dyno reads in wheel BHP so I have converted to flywheel using the below site
http://www.mk5cortinaestate.co.uk/calculator4.php

BHP – 324BHP
Torque – 348ftlb

A huge thank you to Dom and Jason at TVR Power not only for accommodating me a short notice; despite using up over 2 hours of Jasons time and using the dyno cell Dom refused to take any money from me. A very kind gesture and I am most grateful.

 

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Jason showed me some of the work he has been doing with the MBE ECUs which I am now 100% set on getting fitted to mine. Really nice pieces of kit and used by the likes of Caterham, Noble and Harley Davidson so fully type approved and OEM quality. Mine randomly lost all power last weekend, a quick rummage in the foot well and order was restored I think I am on borrowed time with my loom, it has already been repaired twice at great expense, looking at the quality looms Jason makes up for the MBE systems I am convinced this is the way to go.

The Griff did well against the M5s at Sunday service:

What I cannot work out is if I have a mildly tuned 500 with 275BHP at the wheels, how does a completely standard 500 leave me for dead mid track onwards despite getting a good start?

In summary TVR Power = awesome. TVR Power 885 cam = awesome. Driver needs lessons. How the F*** is Dave’s Griff so quick?

T5 Gearbox S10 Tail Housing conversion

Before I begin I must mention David Byron to thank him for his assistance and guidance with this modification.

All TVRs from late Griffith onwards use the Borg Warner T5 gearbox. Griffith and Chimaera used an earlier tail housing for the T5 box which required an additional linkage to bring the shifter out in the correct place.

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On the later ‘T’ cars TVR used the S10 tail housing which presented the shifter in the correct place and did away with the additional linkage.

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The basis of this modification is to retrospectivily fit the later S10 tail housing to the T5 gearbox in my Griffith, thus deleting the additional TVR linkage and improving the feel of the gearbox. I also opted to complete a number of other small enhancements along the way.

John Reid at Readman Racing (Grantura Engineering) has been offering this upgrade for a while and supplies reconditioned S10 tail housings with a new top section with all new bushes and the new selector etc so that the two complete units can just be swapped straight over. From speaking to other owners who have completed the modification a new mount for the gearbox is required and also the TVR remote linkage offsets the gear lever by about 2 inches toward the driver so a dog leg needs to be introduced into the shifter to present it in the same position as before.

As part of the S10 package I also purchased a bronze shift cup and bronze shift forks to replace the standard plastic items again supplied by John Reid.

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I also opted for a replacement Hurst shifter with improved pre-loading to make shifting from 2nd to 3rd easier. I purchased a custom Hurst shifter from Core Shifters built specifically for S10 T5 boxes and with a custom fulcrum height designed for the 6 inch TVR stick.

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Finally I decided upon a custom Stainless Steel gear knob from Chris at Lathewerks in the USA. Machined from a solid block of steel and weighing in at 550G it is approximately 3 times heavier than the original TVR item and has a slightly bigger circumference.

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David Batty my TVR specialist has completed the modifications to the gearbox while changing the clutch and replacing the leaking rear main oil seal.

First impressions are good, it is now easier to select gears at the far end of the box (5th and reverse). The Hurst shifter has reduced the distance between the gears slightly and has a more positive self centering effect. I will update this once I have done over 1000 miles to get a feel for it.

1000 mile update – I have since completed a RWYB day at Santa Pod, a number of long 300+ journeys and a track day at the Lotus test track. I am pleased with the improvements to the gearbox and definitely worthwhile if the box is coming out anyway, I would personally not recommended spending the money on labour removing the box just to have this mod done. The difference is not night and day different just subtly improved.

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Cerbera Seats

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I have always found the original seats very comfortable but lacking in lateral support. Since I have been attending more track days I have struggled with the Griffith seats not only do they not hold me in very well but the seating position is a bit too high and my head touches the roof when wearing a helmet.

Having researched various options I note that popular options for replacing the original seats are Lotus Elise and Mazda MX5 which are both narrow enough to fit. Although the aftermarket options did look appealing in that they are much lighter and offer more support the replacement seats had to be a  ‘TVR’ seat for me to maintain as much originality as possible.

Tuscan seat test
A good friend of mine had a pair of Tuscan seats up for sale which I purchased. I ran this seat in the Griff for most of 2015 to test it out for comfort and also completed a number of track days. I found the Tuscan seat much more supportive than the originals and being able to take the centre cushion out for track days and sit even lower in the car and wedged in is fantastic.

2015-04-06 Tuscan Seat

The issue with the Tuscan seat is for some reason even though the seats felt comfortable they gave me a back ache on long journeys. I also found the seats a bit too wide resulting in me being rattled around in them a bit on track. My main complaint with the seats is the lack of shoulder support, where the bolsters come up around the seat to form the headrest my shoulders sit on the bolsters which is not very comfortable. Lastly although I adore the design of the Tuscan seats I am not sure they entirely suit the Griffith.

Cerbera seat test
I have had a pair of Cerbera seats in the loft for a while now and since had tried them out before but found the seating position a bit too high (about 2cm higher than the standard seats). No good for me as I ideally need to be 2cm lower to accommodate the helmet on track days.

Taking what I had learnt from the Tuscan seats I decided to try out the Cerbera seats again.

Cerbera Seat

I instantly felt the Cerbera seats where more comfortable and I couple of long journeys confirmed no back ache. The shoulder support is good and the seats feel sculpted. The fact the last 100 Griffiths were fitted with these seats from the factory is a big plus for me as technically even though they were not fitted to my car they are an OEM part which did feature in the Griffith.

On the negative side the issue with the height was very apparent as soon as the seats were fitted, I was now sitting far too high, my head was very almost touching the roof without a helmet and the driving position overall not great due to the height. Leg support on the Tuscan seats was also far superior and the Cerbera seats felt a bit short in terms of length.

Knowing I would be getting the seats re-trimmed I decided to modify the bottom foam by removing 75% of the foam thickness from the main cushion but leaving the leg support intact to provide a better support similar to a bucket seat design. The result not pretty but provided a proof of concept. Height wise this was now almost perfect although the very thin layer of foam was not very comfortable at all and very cold. The leg support also worked very well indeed.

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Cerbera Seat modification and re trim
Throughout the testing phase of both seats I had been speaking with Dave The Trimmer who I had the car booked in for the seat re trim with. Dave in my experience is not only a very talented trimmer but is one of few individuals I spoke with who was happy to take on the challenge of potentially creating something bespoke.

Looking at the design of the Tuscan seat and the Cerbera seat I noted that one of the reasons the Tuscan seat is lower is because the Cerebra seat has a solid fibreglass base and the Tuscan seat has webbing.

Cerbera seat
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Tuscan seat
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I arranged to pop in to see Dave to discuss the possibility of modifying the Cerebra seat by cutting out the fiberglass and installing webbing. I also wanted to see if he could make a custom bottom foam based on my butchered original. With the scope of the seat retrim works clearly transforming from a few modifications into more of a complete custom build at this point I was expecting a lot of back tracking and excuses but the answer to both questions was simply “Yeah I can do that”.

The Griff went in with Dave the Trimmer on the 1st February. 1 week later Dave had modified the original seats and was ready to mock up the test foams.

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I also asked Dave to replace the rear seat foams to provide additional comfort. Below the seat can be seen with a prototype bottom foam.

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A couple of weeks later the custom made foams were ready. Below picture shows the new custom foam (left) original prototype (centre) and the original OEM foam (right)

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A week later the seats are finished complete with heated seat elements with the switch hidden at the rear.

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Huge thanks to Dave The Trimmer and the team for doing such a fantastic job creating this bespoke product.