GT6 MK3 front spoiler

[Keith Nock]

I have a late GT6 MK3 post KE 20000  built on the 9th of May 1973 according to my BMIHT certificate, so should theoretically have left the factory with a spoiler according to John Thomason's Book Triumph spitfire and GT6 a guide to originality .I have removed the front valance to replace with a spoiler as fitted to later post February 1973 GT6's spitfire Mk4's and all 1500's however  the fixing  holes for the valance are spaced differently on my cross member and has captive nuts for the valance but no holes for the spoiler  I can soon drill some but has any one else come across this or is John Thompson wrong about the spoiler in his book

Regards keith

 

[NonMember]

I thought the spoiler was fitted to the valance, not instead of it.

[dannyb]

20 minutes ago, NonMember said:

I thought the spoiler was fitted to the valance, not instead of it.

No the spoiler is the valance. I know because I took the spoiler off my 1500 and got myself a mk4 valance.

Can't remember about the fixings though.

Danny

[Colin Lindsay]

If I remember mine from years ago: the lower 'closing piece' fits between the two front valences and bolts to the inner edges. The spoiler fits right across, with a cutout each side for the overriders, and so is much wider with the fixing holes below each sidelight. If you replace the spoiler you need the two little side pieces that fit into the now vacant slots on the front valences, 715863 and 715864 as the metal lower panel 715889 doesn't cover these. Diagram from Rimmers' site:

 

[Keith Nock]

Yes I have removed the valance and the two infill pieces in the 1/4 valances as well, the spoiler fits to the 1/4 valances without issue its the cross member which has no holes for the set screws to go through as they thread into the spoiler on the valance the set screws go from the valance in the captive nuts in the cross member and are a different spacing

Regards Keith

[dougbgt6]

My GT6 is a February 1973, post KE 20,000, it has servo as standard, Sundym glass, big O.75" brake MC, bigger rear brake cylinders. So it is one of the last, but it never had a spoiler.

Doug

[Keith Nock]

Thanks Doug 

Mine is  the same as yours non- Rotoflex Sundym etc, sounds like the spoiler was fitted only to the last few at the very end of production if at all . make's you wonder if john Thomson got it wrong in his book

Regards Keith  

 

[Casper]

Quote

make's you wonder if john Thomson got it wrong in his book

There are errors, no surprise due to the complexity, but they did use up the parts bins as they went along.  Change dates are (nearly always) approximate  and can be considered to be the FIRST Comm. No. it appeared on, not necessarily all thereafter.

C.

  

[Colin Lindsay]

My MK3 was one of the last, from 1973 and with a spoiler, so I removed it as I preferred the 'without' look; besides the spoiler was tatty and badly marked. 

[Mjit]

<pedant>I'm reasonably sure NO GT6s ever left the factory with a front spoiler fitted.  Many left with a front splitter, but that's a very different aerodynamic device.</pedant>

[Colin Lindsay]

19 minutes ago, Mjit said:

<pedant>I'm reasonably sure NO GT6s ever left the factory with a front spoiler fitted.  Many left with a front splitter, but that's a very different aerodynamic device.</pedant>

Now THAT I didn't know, so thought I'd go online to check what the difference was.

From what I've read, splitters are horizontal and attached to the bottom of the front bumper. Spoilers or air dams are used to scoop up air so are angled. 

JohnD and some of the others with racing experience should be able to talk with authority!

[Keith Nock]

My chassis number is KE 22675-O obviously O for over drive and is well after the stated date for spoiler fitted but obviously came from the factory with the valance rather than the spoiler. I have found photos of a new 1500 spitfire chassis on ebay which shows the spoiler mounting holes so that help will drill the chassis to suit if I want i can always refit the valance letter if i want Lots of interesting comments thanks

Regards Keith 

[Colin Lindsay]

9 minutes ago, Keith Nock said:

My chassis number is KE 22675-O obviously O for over drive and is well after the stated date for spoiler fitted but obviously came from the factory with the valance rather than the spoiler. I have found photos of a new 1500 spitfire chassis on ebay which shows the spoiler mounting holes so that help will drill the chassis to suit if I want i can always refit the valance letter if i want Lots of interesting comments thanks

Regards Keith 

Still the same lovely green mk3, Keith?

[Keith Nock]

Hi Colin

Yes haven't used it much recently Keep doing slight improvements and tweaking the finish, maybe get to use it more next year . I have just removed the gas struts on the bonnet and gone back to the original factory bonnet prop as Was not  happy with the they made the inner wheel arches distort  

Keith

[Mjit]

23 hours ago, Colin Lindsay said:

Now THAT I didn't know, so thought I'd go online to check what the difference was.

From what I've read, splitters are horizontal and attached to the bottom of the front bumper. Spoilers or air dams are used to scoop up air so are angled. 

JohnD and some of the others with racing experience should be able to talk with authority!

A splitter, well, splits the airflow and lets you control how much goes where rather than just letting the air make it's own mind up.  The best design is a horizontal blade and that's what you see in motorsport.  They don't look that 'nice', are very subject to damage, and have a habit of trying to cut off pedestrians feet on the public highway though so road car splitters tend to by styled to look nice while still being effective.  If you look at the Spitfire front splitter it's basically a horizontal blade, just very 'puffed out' and 'rounded off' to blend with the general car styling and make it less cutty in an accident.  It still splits airflot hitting that area of the car, sending some of it down under the car/the rest up through the engine bay.  Having driven my Spitfire both with/without it actually makes a huge difference at higher speeds, sending more air under the car and countering the front end lift generated by the big, wing-like bonnet which can make the steering go rather loose.

A spoiler, well, spoils the airflow.  When any 'wing-like' shape passed through the air going 'the long way around' (i.e. over) has to go faster than the air going 'the short way' (i.e. under), and faster moving air creates a lower pressure zone.  Now if that wing shape is an aircraft wing that's great, you WANT to to get lifted up.  If that wing like shape is a car body though a bit of lift is good but too much and you start to lose force between the tyres and the road.  This makes the steering scary light, makes it easier to wheel spin, and easier to lose traction and under/over steer.  A spoiler basically gets in the way of the nice airflow over the car, making it slower, tubulent flow that doesn't produce as much lift.  They can also have a secondary effect which is to intentionally mess up the airflow off the rear edge of the body.  Left to it's own devices you tend to get a very turbulent wake behind the car where the under/over flows rejoin and feed one another - and that's drag trying to suck the car backwards.  You can use a spoiler to 'mess with' the upper flow before the natural rejoin point, stopping the 2 flows interacting as much and causing so much wake drag.  The spoiler itself actually increases drag but by less than it reduses the wake drag.

And then you have things like gurney flap, which are just witchcraft!

[Dave the tram]

Interesting to read your comments on front stability with and without spoiler Mijt. I took mine off my  Mk 3 GT6 some years ago as I prefer the look without and was surprised to find removal cured the front end lightness and wander above 60mph, which was counter- intuitive. I just can’t remember now though if I removed it at the same time as lowering the front a bit as it sat too high. Mine had the side valences as well as a spoiler. Might put it back on one day to check the point as I’m sure just the removing the spoiler improved it.

Dave

[Colin Lindsay]

3 hours ago, Mjit said:

A splitter, well, splits the airflow and lets you control how much goes where rather than just letting the air make it's own mind up.  The best design is a horizontal blade and that's what you see in motorsport.  They don't look that 'nice', are very subject to damage, and have a habit of trying to cut off pedestrians feet on the public highway though so road car splitters tend to by styled to look nice while still being effective.  If you look at the Spitfire front splitter it's basically a horizontal blade, just very 'puffed out' and 'rounded off' to blend with the general car styling and make it less cutty in an accident.  It still splits airflot hitting that area of the car, sending some of it down under the car/the rest up through the engine bay.  Having driven my Spitfire both with/without it actually makes a huge difference at higher speeds, sending more air under the car and countering the front end lift generated by the big, wing-like bonnet which can make the steering go rather loose.

A spoiler, well, spoils the airflow.  When any 'wing-like' shape passed through the air going 'the long way around' (i.e. over) has to go faster than the air going 'the short way' (i.e. under), and faster moving air creates a lower pressure zone.  Now if that wing shape is an aircraft wing that's great, you WANT to to get lifted up.  If that wing like shape is a car body though a bit of lift is good but too much and you start to lose force between the tyres and the road.  This makes the steering scary light, makes it easier to wheel spin, and easier to lose traction and under/over steer.  A spoiler basically gets in the way of the nice airflow over the car, making it slower, tubulent flow that doesn't produce as much lift.  They can also have a secondary effect which is to intentionally mess up the airflow off the rear edge of the body.  Left to it's own devices you tend to get a very turbulent wake behind the car where the under/over flows rejoin and feed one another - and that's drag trying to suck the car backwards.  You can use a spoiler to 'mess with' the upper flow before the natural rejoin point, stopping the 2 flows interacting as much and causing so much wake drag.  The spoiler itself actually increases drag but by less than it reduses the wake drag.

And then you have things like gurney flap, which are just witchcraft!

Great explanation, many thanks. I don't think I need one for the Herald just yet, though...

[Mjit]

On 21/10/2022 at 15:48, Dave the tram said:

Interesting to read your comments on front stability with and without spoiler Mijt. I took mine off my  Mk 3 GT6 some years ago as I prefer the look without and was surprised to find removal cured the front end lightness and wander above 60mph, which was counter- intuitive. I just can’t remember now though if I removed it at the same time as lowering the front a bit as it sat too high. Mine had the side valences as well as a spoiler. Might put it back on one day to check the point as I’m sure just the removing the spoiler improved it.

Dave

Hah! I put one ON my Mk IV Spitfire because I though it looked better and found it cured the same issue

Not the only thing that can be counter intuitive - the front of my car used to tramline badly on worn motorway inside lanes...until I softened the rear shocks - but important thing it just go with whatever works for you.

[Keith Nock]

[Keith Nock]

Removed valance and infills and fitted later original spoiler off a spitfire  will see if it make a difference to the handling

[dannyb]

11 hours ago, Keith Nock said:

Removed valance and infills and fitted later original spoiler off a spitfire  will see if it make a difference to the handling

Didn't seem to make any difference to the handling of my spitfire when I removed it.  Its main purpose may have been to force air into the radiator.

Danny