Exhaust Manifolds

[jcpgasoline]

Could someone confirm whether manifolds of the same bore or length were used on the various variants of the speed six engine? I.e. Did the 3.6 & 4.0 and the Red Rose and "S" versions all use the same exhaust manifolds?

[VARLEYHYD]

4.0 'S 'variants & sag have larger catalyst flanges

G

[jcpgasoline]

VARLEYHYD said:

4.0 'S 'variants & sag have larger catalyst flanges

G

Thanks, but are the primary pipes (before the cats) all the same bore & length irrespective of the variant?

[VARLEYHYD]

jcpgasoline said:

VARLEYHYD said:

4.0 'S 'variants & sag have larger catalyst flanges

G

Thanks, but are the primary pipes (before the cats) all the same bore & length irrespective of the variant?

Yes, sorry all pipes same bore

[jcpgasoline]

VARLEYHYD said:

jcpgasoline said:

VARLEYHYD said:

4.0 'S 'variants & sag have larger catalyst flanges

G

Thanks, but are the primary pipes (before the cats) all the same bore & length irrespective of the variant?

Yes, sorry all pipes same bore

Many thanks.

[jcpgasoline]

VARLEYHYD said:

Yes, sorry all pipes same bore

Last question - promise!

What is the inside diameter of the exhaust manifolds (primaries)?

[PascalBuyens]

VARLEYHYD said:

Yes, sorry all pipes same bore

But not same length on standard TVR manifolds...

[clive f]

the outside diameter of the headers on my sag are 48mm, however I have a spare set of manifolds in the garage and the o/d on those is 45mm.

strange, but typical TVR I suppose.

[m4tti]

According to this thread T40ORA had the RG equal length pipes fitted to his tamora along with the FFF.

[jcpgasoline]

m4tti said:

According to this thread T40ORA had the RG equal length pipes fitted to his tamora along with the FFF.

Which thread would that be?

[m4tti]

jcpgasoline said:

Which thread would that be?

Whoops sorry.. bad pasting

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[jcpgasoline]

m4tti said:

Whoops sorry.. bad pasting

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Thanks for that.

[s5tvr]

I have an early 3.6 red rose T350c and when spec'd from new by the previous owner the "S" spec engine manifold was fitted rather than the standard manifold which apparently was of a narrower bore.

[TA14]

clive f said:

the outside diameter of the headers on my sag are 48mm, however I have a spare set of manifolds in the garage and the o/d on those is 45mm; strange, but typical TVR I suppose.

Sags should have the larger bore but rather than have cars sat in the factory waiting for manifolds quite a few (most?) left with the standard T-car part.

[craigcaf]

What's the easiest way to tell the difference between the manifolds? What's the external primary pipe diameters for std vs S spec?

[clive f]

from measuring a spare set hanging in the garage they are 45mm compared to 48mm.

[Andy_mr2sc]

Next obvious question then. Do the larger primary pipes give an increase in power over the smaller ones. Also has anyone tried a back to back test with the RG ones and seen an increase?

[jcpgasoline]

Andy_mr2sc said:

Next obvious question then. Do the larger primary pipes give an increase in power over the smaller ones. Also has anyone tried a back to back test with the RG ones and seen an increase?

Depends on the engine capacity. But for a given engine displacement, a wider bore exhaust manifold can have the effect of moving the peak torque further up the rev range which results in more peak power at the expense of mid-range torque. But bigger isn't always better and the manifold bore can simply be too large for the engine, in which case both torque and power are lost.