Discussion
hallsie said:
Are all of the 'M' series exhausts ridiculously low?
Ive only got about 100mm.. oops, sorry forgot this was the classics forum, 4 Inches clearance!
Stu
Glad its the Exaust was getting worried when i saw the title pictures please then we can see what bracket your using as mine is higher than that but not OE Exaust but modified stainless with a different rear bracket which does pull it up tighter than some i have seen still hits on speed bumps unless i am carefull.Ive only got about 100mm.. oops, sorry forgot this was the classics forum, 4 Inches clearance!
Stu
A
My M ride rather low, with 19cm from the ground to the frame. Silencers is 2x2 4" round that is pulled aprox 1 cm up into the drive shaft tunnel, giving a ground clerance of 9cm. I havn't had any problems som far, but one reason could be that i have a bit more clerance (12cm) under the gearbox, where it's most prone to touch the ground
I really admire your work!
Your a very very clever guy. .. (thats not being patronising).
But
Can you explain why you didnt you put the exhaust box partly up between the chassis centre tubes?
You would have gained the chassis clearance you were looking for.
I saw Neil Hookway's Tuscan racer many years ago at the TVRCC at Pembrey and had the same done to my Vixen.
Darren
Your a very very clever guy. .. (thats not being patronising).
But
Can you explain why you didnt you put the exhaust box partly up between the chassis centre tubes?
You would have gained the chassis clearance you were looking for.
I saw Neil Hookway's Tuscan racer many years ago at the TVRCC at Pembrey and had the same done to my Vixen.
Darren
I really admire your work!
Your a very very clever guy. .. (thats not being patronising).
But
Can you explain why you didnt you put the exhaust box partly up between the chassis centre tubes?
You would have gained the chassis clearance you were looking for.
I saw Neil Hookway's Tuscan racer many years ago at the TVRCC at Pembrey and had the same done to my Vixen.
Darren
Your a very very clever guy. .. (thats not being patronising).
But
Can you explain why you didnt you put the exhaust box partly up between the chassis centre tubes?
You would have gained the chassis clearance you were looking for.
I saw Neil Hookway's Tuscan racer many years ago at the TVRCC at Pembrey and had the same done to my Vixen.
Darren
Yes, due to beeing "pratical damaged" due to too many years in shool and my enginnering education :-) From a ridgity point of view, are the biggest problem in the M series frame construction, the lack of crossmembers between the 2 lower tubes. So to repair that, did I fit some bracing there. Further do the 2 crossmembers in the rear end construction, together with the diff, allso prohibit how much the silencers can be lifted.
"Original" exhaust used 1,5" tubes and oval can's. The design for the Jag engine required 2,25" tubes in a "striaght thru" design wit hthe compromize of 4" can's, 4 off, to clear the 2 crosmembers in the rear end. Clerance is following the old "rule of thumb" ... if you can get your fingers between something, it won't rattle when the engine moves.
"Original" exhaust used 1,5" tubes and oval can's. The design for the Jag engine required 2,25" tubes in a "striaght thru" design wit hthe compromize of 4" can's, 4 off, to clear the 2 crosmembers in the rear end. Clerance is following the old "rule of thumb" ... if you can get your fingers between something, it won't rattle when the engine moves.
daza said:
I really admire your work!
Your a very very clever guy. .. (thats not being patronising).
But
Can you explain why you didnt you put the exhaust box partly up between the chassis centre tubes?
You would have gained the chassis clearance you were looking for.
I saw Neil Hookway's Tuscan racer many years ago at the TVRCC at Pembrey and had the same done to my Vixen.
Darren
Thanks Darren, Thanks Darren!Your a very very clever guy. .. (thats not being patronising).
But
Can you explain why you didnt you put the exhaust box partly up between the chassis centre tubes?
You would have gained the chassis clearance you were looking for.
I saw Neil Hookway's Tuscan racer many years ago at the TVRCC at Pembrey and had the same done to my Vixen.
Darren
I went out to have a look and remind myself as to why I didnt try abd get it up into the chassis a bit more,
The manifolds seem to kick the rest of the exhaust down the most, and now Ive re looked it appears that I could possible re adjust a bit more and get the two single boxes up a bit more which in turn will push up the single rear box a bit more.
One MOT'd Illmake tracks to getting a new set of manifolds made that might get me a few more contimeters..... or inches.
the rule of 'fingers' as spacing will be employed aswell,
Stu
Stu..
If your going for a new manifold.. my design swept forward then down... before going back and exiting above and just in front of the gearbox mount (my Vixen was the first Zetec conversion. ..)
The exhaust continues along side the gearbox before dipping for the first oval box with a single exit...with another subtle kink for the back box which is twin upswept (pictures and measurements if you require)..
I remember driving up to Scotland with the old exhaust with sparks flying... after surgery... never had any problems again
D
If your going for a new manifold.. my design swept forward then down... before going back and exiting above and just in front of the gearbox mount (my Vixen was the first Zetec conversion. ..)
The exhaust continues along side the gearbox before dipping for the first oval box with a single exit...with another subtle kink for the back box which is twin upswept (pictures and measurements if you require)..
I remember driving up to Scotland with the old exhaust with sparks flying... after surgery... never had any problems again
D
Getting the boxes up as much as possible is obviously paramount. If you've put in scaffolding preventing that, then such is to be considered as a design fault ! 
(only pulling your leg, my danish friend....)
As Stu rightly stated the lenght/rate of turn of the manifolds/downpipes dictates the position of the mid box, hence its clearance.
There is however a further criterium, namely the suspension and tyres (in other words, how high the chassis is from the ground in the first place). A 195/60 tyre will give about 1/2" less clearance then a 185/80 (OE), adjustable shocks can compensate (partly) for this
My car, on 185//80 has the front shocks adjusted at their lowest, whilst the rears are 20 mm up, never had any issues with clearance.........
F
(only pulling your leg, my danish friend....)As Stu rightly stated the lenght/rate of turn of the manifolds/downpipes dictates the position of the mid box, hence its clearance.
There is however a further criterium, namely the suspension and tyres (in other words, how high the chassis is from the ground in the first place). A 195/60 tyre will give about 1/2" less clearance then a 185/80 (OE), adjustable shocks can compensate (partly) for this
My car, on 185//80 has the front shocks adjusted at their lowest, whilst the rears are 20 mm up, never had any issues with clearance.........
F
bluezeeland said:
Getting the boxes up as much as possible is obviously paramount. If you've put in scaffolding preventing that, then such is to be considered as a design fault ! (only pulling your leg, my danish friend....)
As Stu rightly stated the lenght/rate of turn of the manifolds/downpipes dictates the position of the mid box, hence its clearance.
There is however a further criterium, namely the suspension and tyres (in other words, how high the chassis is from the ground in the first place). A 195/60 tyre will give about 1/2" less clearance then a 185/80 (OE), adjustable shocks can compensate (partly) for this
My car, on 185//80 has the front shocks adjusted at their lowest, whilst the rears are 20 mm up, never had any issues with clearance.........
F
Shocks and springs are standard refurbed original items, as were the 'T; slot alloys, but Ive just changed them for some minilite type 15 alloys with 205 65 tyres, so that has made a bit of a difference. (only pulling your leg, my danish friend....)As Stu rightly stated the lenght/rate of turn of the manifolds/downpipes dictates the position of the mid box, hence its clearance.
There is however a further criterium, namely the suspension and tyres (in other words, how high the chassis is from the ground in the first place). A 195/60 tyre will give about 1/2" less clearance then a 185/80 (OE), adjustable shocks can compensate (partly) for this
My car, on 185//80 has the front shocks adjusted at their lowest, whilst the rears are 20 mm up, never had any issues with clearance.........
F
Heightswitch said:
Why have a mid box at all?? Just run with a silencer.. My racer has a very small single rear silencer which will probably sap some power but has no trouble meeting noise regs??
N.
The first 2 boxes are tiny, and the second single box is also quite stubby, in all they are the same length as the on I took off.N.
plus, my wife is having the car and I dont think she wants or needs a straight through racing exhaust!!
Ill get it up on ramps soon and re set it, then report back.
Stu
205/65/15 has -4 mm less diameter than 185/81/14, so should be OK, shocks standard refurbed, so OK
Leaves downpipes, probably the mid box is touching (?) hence downpipes are the culprit. They should be as per Andrew', that is about as low as the the engine and gearbox
Please do report, will install new manifolds/heads shortly myself, so interested in your findings !
Leaves downpipes, probably the mid box is touching (?) hence downpipes are the culprit. They should be as per Andrew', that is about as low as the the engine and gearbox
Please do report, will install new manifolds/heads shortly myself, so interested in your findings !
heightswitch said:
Why have a mid box at all?? Just run with a silencer.. My racer has a very small single rear silencer which will probably sap some power but has no trouble meeting noise regs??
N.
Best Neil, N.
What type of "small" silencer do you have?
Dimensions or better Compagny/Trademark.
Thanx. Hans
Hansoplast said:
Best Neil,
What type of "small" silencer do you have?
Dimensions or better Compagny/Trademark.
Thanx. Hans
Its a tidgy little one but a silencer as opposed to a straight through box. yes it will rob a few HP but it makes it pass noise regs and was designed by an exhaust specialist fabricator.What type of "small" silencer do you have?
Dimensions or better Compagny/Trademark.
Thanx. Hans
I will see if I can dig out a photo.
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