GT6 MKII Inlet Manifold - Tuning Options

In a conversation with a tuning expert recently, and in trying to research what period tuning mods allowable to tweak my Classic Road rally car - I was advised that the Inlet manifld should really be replaced with a Triumph

2000 inlet manifold!?.. as this will permit the improvements in breathing necessary. This was suggested as being the beginning of the tuning improvements.

Bonnet clearance is a concern, as is passing eligibility scrutineering - what experiences and or solutions can readers offer in this respect. Kas Kastners Competition Manual suggests modifications only to the existing manifold. What alternatives are there.

I would appreciate answers to this particular question - but will also be happy to hear from anyone with experience of a thorough tune for a MKII GT6. I am aware of the usual simple mods to Carburation ( running HS4's) K&N's and 6-3-1 vs 6-2-1 exhaust manifolds but wonder also if anyone has experience of the relative merits of Twin vs single exhaust ???

neil snipped-for-privacy@hotmail.com

Reply to
Glaramaraman
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"Glaramaraman" realised it was Mon, 14 Mar 2005

19:54:21 +0000 (UTC) and decided it was time to write:

There is no merit to a twin exhaust system on a GT6, unless you don't expect to have any ground clearance or aren't bothered running it through the interior, in which case you can probably do away with the heater.

Reply to
Yippee

In message , Glaramaraman writes

There were two manifolds used with SU carbs on the 6 cylinder engine, (as well as the Stromberg twin manifold as originally on the GT6). The rarer of the two SU manifolds was fitted on the 2.5 engine and has noticeably longer inlet tract lengths than the other. I don't know if this manifold will fit in a GT6 though. I believe it will if you replace the airbox with K&N filters or similar. I can take a photo of the long-type 2.5 manifold if you want so you can recognise one when you see it.

Twin exhausts are (in my opinion) simply 'tarting up' devices. A good single straight-through single silencer is likely to be more effective, though it doesn't have the visual impact.

BTW, I've seen the 2.5 PI manifolds converted to take modern EFI injectors, and driven by user-programmable injection controllers. A lot of work, but if you really want to get HP out of the GT6 engine, it's the way to go. Hope your gearbox and diff stand it though, they are a weak part of tuned GT6s or Vittesses.

Reply to
Chris Morriss

The Triumph 2000 and 2.5 Saloons had the engines canted over to the right. The inlet manifolds are angles to bring the carbs level, used in a Vitesse or GT6 applications these manifolds will push the carbs up through the bonnet. You will doubtless be aware of the adaptor plates to fit HS4 or HS6 carbs to the original manifold. I've not got involved with tuning the Triumph 6 cylinder engines myself, but one of the most impressive I've seen/heard was a Lucas PI system set up on a 2000 Saloon. Cheers, Bill.

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Reply to
Bill Davies

Just a note of thanks to all who posted. Looks like I'll have to stick with the stock manifold

Reply to
Glaramaraman

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