Extractor/Header for 6cyl.

[Malbaby]

There are a few on the market.

Which one is the best value for money?

[john.r.davies]

You mean a 6-3-1 manifold?   The criterion is the length of the primaries, which governs the rev range in which they resonate and act as extractors.    Like organ pipes, the shorter the higher.    Gareth Thomas, a strange man and an excellent engineer, recommends that they should be 0.43m long  and exactly equal to work around top revs:

They need to be longer to work at mid range, but those would need to be bespoke and will take up a lot of space or have ground clearance problems.

John 

[OldBob]

Your basic choice is either a 6-3-1  OR a  6-2-1 manifold.

Firing order on a 6cyl is : 1-5-3-6-2-4 

So with the 6-3-1 manifold, it will have ports/pipes 1 & 6 paired together,  then 5 & 2  paired and 3 & 4 paired. Each of those 3 three pairs then goes into one large diameter pipe at the bottom of the manifold (hence the name 6 into 3 into 1 ).

This is good as it allows two other cylinders to fire as the gas escapes down the first stage of the manifold before another exhaust port empties into the same pair.

Whereas on the 6-2-1 manifold, it will be 1 & 2 & 3 ports which are joined up at the top of the manifold, leaving pipes 4 & 5 & 6 linked at the rear. These 2 pipes then go into the large lower section -so you get the '6 into 2 into 1' pipe system - which means only one other cylinder fires before another port empties into the same manifold section.

Generally a 6-3-1 is a larger budget item, but arguably better, HOWEVER, on either of these systems, pipe lengths can and do come into play which will affect manifold efficacy.

For reference, the TR6 standard factory cast iron manifold is a 6 - 1  and works quite well. You can get 150+ bhp on one of those.

Cheers

Bob

[PodOne]

Just for some debate and evidence has anyone compared the bhp results of Std cast manifold, 6-3-1 and 6-2-1 on a dyno with no other changes?

Reason I ask is that when I made the comparison using the same dyno on the MX5 with std manifold to an off the shelf extractor and then a custom the gains were minimal within 2-5 bhp of each even with a custom exhaust system concluding that given the cost/bhp the std manifold was acceptable and the money was better used elsewhere.

Did Triumph get it right? 

Andy  

[Motorsport Mickey]

Andy,

There is no "silver bullet" for performance parts, especially on the TR 4 cylinder engine but applies pretty equally to most cars. If a manufacturer could gain 10 or 15 hp (about 10% on Triumph engines) just by the substitution of 1 part at reasonable cost...they would.

 Mick Richards

Edited March 28 by Motorsport Mickey

[PodOne]

2 minutes ago, Motorsport Mickey said:

Andy,

There is no "silver bullet" for performance parts, especially on the TR 4 cylinder engine but applies pretty equally to most cars. If a manufacturer could gain 10 or 15 hp (about 10% on Triumph engines) just by the substitution of 1 part 

Hi Mick 

Totally agree I suspect there's a lot of clever marketing behind a lot of it but just occasionally the bean counters at the development stage did leave some room for improvement.

[ntc]

Yes they did don’t waste your money and it’s good to see the forum is now back to normal 

[Motorsport Mickey]

12 hours ago, PodOne said:

Hi Mick 

Totally agree I suspect there's a lot of clever marketing behind a lot of it but just occasionally the bean counters at the development stage did leave some room for improvement.

Oh the improvements are there, it's just they require the car be improved by application of "suites" of parts and work.

Reworked head, bigger valves, performance camshaft, better injection system or using Weber carbs, and then internal engineering work to utilise these parts. You can't add an exhaust = 3hp, add a head = 10 hp et etc, the law of incremental advantageous improvements comes about. By altering one item it gives an advantage which is multiplied by the next alteration better than by addition, ie a 3hp performance exhaust gain when multiplied by another complimentary addition of a head for 10hp gives rather better than the 3 hp+ 10hp addition sum. You hopefully carry on this "aggregation of small improvements" throughout the engine which pays you back with a gob of power...sadly only by transmogrification of parts and work for...money. That's why the factory didn't do it originally .

Mick Richards        

Edited March 29 by Motorsport Mickey

[Tom Fremont]

6-3-1 pairing 1-6,2-5 and 3-4 gives them equal firing order spacing. Richard Good's version has equal length primaries and secondaries which he tested against Phoenix's version where they are apparently unequal and found a big difference in his favor. The downside is Richard " cannot build it in stainless " ostensibly due to the metal's relative reluctance to bend into the tight radius required for 1 & 6 cylinders where mild steel can. He has his " ceramic " coated in (3) different temperature ranges.

I have experience with this on my trick engine with very high lift cam and triple DCOEs ( of course  ) and it brought in the mid range where a 6-2-1 from Racetorations would not, no matter what I tried in the Webers. Moreover, it did so with (1) size smaller main jet and (7) sizes larger air corrector!

My CP spec driver OTOH does fine with the 6-2-1 ( which is why I tried it first on the trick engine ).

My takeaway is the breathing is optimized with a proper [ GOODPARTS type ] 6-3-1 and (6) throttles. Note that triple singles cannot draw evenly due to varying firing order spacing on an inline 6.

Richard Good acknowledges that every type of manifold design makes compromises. In the case of his, I suppose a 6-1 banana bunch style full-race manifold will beat it, but not make it as drivable on the street.

Tom
 

[john.r.davies]

There seems to be some misunderstanding above about how an "extractor" manifold works!

It relies on the nature of a six cylinder engine, which is two three-cylinder engines joined as mirror images of each other.   An Extractor links the cylinders that fire just 360 degrees apart, as said above 6 & 1, 5&2, 4&3.     The pulse of exhaust gases from one of the pair reaches the junction and is reflected up the other branch.   If the length of the Primary is correct, then this reflected wave will reach the other port just as that opens, in the negative phase of the  pulse wave.  The negative pressure will promote extraction of exhaust gases, hence the name.     This will happen best at a particular engine speed that depends on the primary length.   The longer the primary, the lower the resonance speed, but really long primaries are for F1 and the birds.

As you would expect from the above, such interference is impossible with a four cylinder engine (or an V8), so I'm sorry, Andy, you won't see it at all with an MX5, or with TR4s.  Yes, it would be good to see a strict comparison on the dyno, but AFAIK it's never been done, or never made public.

John

 

[PodOne]

29 minutes ago, Motorsport Mickey said:

Oh the improvements are there, it's just they require the car be improved by application of "suites" of parts and work.

Reworked head, bigger valves, performance camshaft, better injection system or using Weber carbs, and then internal engineering work to utilise these parts. You can't add an exhaust = 3hp, add a head = 10 hp et etc, the law of incremental advantageous improvements comes about. By altering one item it gives an advantage which is multiplied by the next alteration better than by addition ie a 3hp performance exhaust gain when multiplied by another complimentary addition of a head for 10hp gives rather better than the 3 hp+ 10hp addition sum. You hopefully carry on this "aggregation of small improvements" throughout the engine which pays you back with a gob of power...sadly only by transmogrification of parts and work for...money. That's why the factory didn't do it originally .

Mick Richards        

Correct being on that journey with the MX5 and not every mod added to the recipe some were reversed through a long process of evolution.

The 1.6 was derived from the Mazda 323 Turbo and the bottom end retained the lubrication system including oil squirters to the bottom of the pistons making it a good basis for re-requiring boost which BBA did as a dealer option. That got you around 200bhp with a bigger Garret turbo and kit from FM got you a reliable 240bhp with a good ecu and tuning. Wanting a challenge I pushed on with a 1.6 forged bottom end uprated oil pump, balanced with a ATI damper. The head was CNC'd ported with bigger SS inlet and exhaust valves, vernier cams wheels but interestingly produced more linear power using the std cam running 3 Barr, COP's and full sequential injection saw 420bhp and 390ft/lbs with loads of other mods to everything else. Wasn't the end would run 450bhp but the weakest link was the gearbox so was run at the lower fig. Even then the 5 speeds would last a couple of races the 6 speed perhaps longer but 1st was useless a Quaife gear set bit better but the gear box case was still twisting due to the torque and shearing the case bolts even when replaced wit 11.9 cap bolts. All done when gearboxes could be had for £50 -£100. Great sleeper car and loads of fun but no good on even a damp road it would bite you!

Which it did hence by royal command no more modified cars and she had to go to someone with more ability. 

Love to do the same with a 6 or even a 4 just for something to do rather than a engine swap but then divorce is more expensive!   

[BlueTR3A-5EKT]

2 hours ago, Tom Fremont said:

6-3-1 pairing 1-6,2-5 and 3-4 gives them equal firing order spacing. Richard Good's version has equal length primaries and secondaries which he tested against Phoenix's version where they are apparently unequal and found a big difference in his favor. The downside is Richard " cannot build it in stainless " ostensibly due to the metal's relative reluctance to bend into the tight radius required for 1 & 6 cylinders where mild steel can. He has his " ceramic " coated in (3) different temperature ranges.

I have experience with this on my trick engine with very high lift cam and triple DCOEs ( of course  ) and it brought in the mid range where a 6-2-1 from Racetorations would not, no matter what I tried in the Webers. Moreover, it did so with (1) size smaller main jet and (7) sizes larger air corrector!

My CP spec driver OTOH does fine with the 6-2-1 ( which is why I tried it first on the trick engine ).

My takeaway is the breathing is optimized with a proper [ GOODPARTS type ] 6-3-1 and (6) throttles. Note that triple singles cannot draw evenly due to varying firing order spacing on an inline 6.

Richard Good acknowledges that every type of manifold design makes compromises. In the case of his, I suppose a 6-1 banana bunch style full-race manifold will beat it, but not make it as drivable on the street.

Tom
 

Plus one for GoodParts.

If thinking of obtaining just be sure and have confirmed the manifold you buy is suitable for Right Hand Drive steering cars.   It is quite annoying to find some clown put a steering shaft where the exhaust manifold pipe is.   Clubbing it with a mallet to relieve the rubbing will probably negate any benefits tge manifold provided.

i speak from experience of seeing 50 Janspeed LCB type Sprite exhaust manifolds shipped to the US only to have them returned as ‘do not fit’.  Steering is in the way.

[JohnC]

6 hours ago, PodOne said:

Just for some debate and evidence has anyone compared the bhp results of Std cast manifold, 6-3-1 and 6-2-1 on a dyno with no other changes?

I have compared a TT1200 6-2 (not 6-2-1; it went into a twin pipe system with a balance pipe further back) with a standard cast iron manifold. Same dyno, no other changes, and the engine was bog standard CP. The cast iron manifold generated ~10-15 lb.ft more torque until 4000RPM, and at 4500RPM both were about equal. The 6-2 then generated about 5 lb.ft more until 5500RPM, where I stopped. The 6-2 manifold max power was ~5bhp more than the OE cast iron, but not until over 5000RPM.

My conclusion (borne out by the opinion of others better qualified) is that the TT1200 is much better suited to a race car being driven high in the rev range, than to a daily driver. As Neil says, the Triumph engineers did get it right. The OE cast iron manifold does the job well.

I daresay that if the engine had been improved (balancing in particular, but head work as well) the TT1200 may have given better results. FWIW since then (2007) I have had the engine balanced, the head worked on and the CR raised a bit. But I have thrown out the TT1200 so we'll never know!

Cheers,
John

[BlueTR3A-5EKT]

7 hours ago, JohnC said:

I have compared a TT1200 6-2 (not 6-2-1; it went into a twin pipe system with a balance pipe further back) with a standard cast iron manifold. Same dyno, no other changes, and the engine was bog standard CP. The cast iron manifold generated ~10-15 lb.ft more torque until 4000RPM, and at 4500RPM both were about equal. The 6-2 then generated about 5 lb.ft more until 5500RPM, where I stopped. The 6-2 manifold max power was ~5bhp more than the OE cast iron, but not until over 5000RPM.

My conclusion (borne out by the opinion of others better qualified) is that the TT1200 is much better suited to a race car being driven high in the rev range, than to a daily driver. As Neil says, the Triumph engineers did get it right. The OE cast iron manifold does the job well.

I daresay that if the engine had been improved (balancing in particular, but head work as well) the TT1200 may have given better results. FWIW since then (2007) I have had the engine balanced, the head worked on and the CR raised a bit. But I have thrown out the TT1200 so we'll never know!

Cheers,
John

Good info John.

Glad to read you added a balance connection when the TT1200 was fitted.  The original cast iron manifold having of course a balance connection/casting hole, internally just before the down pipe flange.

[JohnC]

42 minutes ago, BlueTR3A-5EKT said:

Glad to read you added a balance connection when the TT1200 was fitted.  The original cast iron manifold having of course a balance connection/casting hole, internally just before the down pipe flange.

Yes and before I added the balance pipe, performance aside, it sounded like an angry bird was following me whenever the engine was on over-run!

Edited March 29 by JohnC

[john.r.davies]

TriumphTune described the TT1200 as an "Extractor" manifold, but classified it as  "Road" type.   It collects the front three and back three cylinder primaries into two tail pipes, so cannot work in the same way as I described above.  They also did a long primary "Competition" version, FS1230 (why not a TT designation?) while their TT1240 was a true  6-3-1 extractor.

JOhn

[stuart]

What you want is this.

Stuart.

 

[RogerH]

That is a nice piece of pipe bending  

[BlueTR3A-5EKT]

1 hour ago, john.r.davies said:

TriumphTune described the TT1200 as an "Extractor" manifold, but classified it as  "Road" type.   It collects the front three and back three cylinder primaries into two tail pipes, so cannot work in the same way as I described above.  They also did a long primary "Competition" version, FS1230 (why not a TT designation?) while their TT1240 was a true  6-3-1 extractor.

JOhn

FS prefix meant it was from Falcon Stainless steel exhaust maker.   TT prefix items came in mild steel only from another supplier.    .   The first few of the 6-3-1 sold by Triumph Tune I think were supplied by Gareth Thomas.    They were copied by many.   The rest is history.

[john.r.davies]

Thank you, Peter!  Another factoid to store away!

John

[michaeldavis39]

3 hours ago, stuart said:

What you want is this.

Stuart.

 

That looks like one of Gareth Thomas headers right there- as said many times copied but never very accurately as its hard to do and therefore very expensive- totally over the top for a road car obviously.

[Spit_2.5PI]

3 hours ago, stuart said:

What you want is this.

Stuart.

 

Made by Chris Tullet Exhausts in Aylesbury circa 2009 if I'm not mistaken. I wonder if they still have the design files?

Cheers, Richard

[stuart]

20 minutes ago, michaeldavis39 said:

That looks like one of Gareth Thomas headers right there- as said many times copied but never very accurately as its hard to do and therefore very expensive- totally over the top for a road car obviously.

No its not its from Australia

Stuart.

[stuart]

2 minutes ago, Spit_2.5PI said:

Made by Chris Tullet Exhausts in Aylesbury circa 2009 if I'm not mistaken. I wonder if they still have the design files?

Cheers, Richard

Doubt it as its from Australia. Ive had that picture on file from long before that.

Stuart.

Edited March 29 by stuart

[Spit_2.5PI]

Fair enough Stuart. They fabricate exhausts in the same way and were doing something for a Triumph which was very similar to your image - always wish I had taken a picture at the time.