500 Inlet manifold ported ?

[hiltonig]

On a 500 were the inlet manifolds already ported to 45mm ??? ACT are selling these

http://www.actproducts.co.uk/shop/ti020a-inlet-man...

[rev-erend]

I think they are 38mm as standard in the 500.. with a 68mm throttle.

[TVR Beaver]

does going to 45mm loose you torque at all at the bottom end??... anyone know?

[spend]

Only if its badly done.. You guys are obsessed with the size, but the subtle changes in radius make greater differences IMHO.

[TVR Beaver]

well.. you know why I'm asking... just wondered if after all, the problem could be in the 45mm manifould.... Ray said they close them down a bit where they go into the heads to speed up flow... but in my mind this introduces a step and turbulance?.... Not sure what matching was done head to manifoulds on the 500's... from what Dom say's they were done to a template so should be close.. but not actualy matched in the true sence.... Did read somewhere about fluid matching of runners also... Take 10 ltrs of water and time how long it takes it to run through the individual runners.. then fettle e'm until they are all the same. Assume you do this from the top of the trumpett to the inlet to the head... sounds like a bit of fun! big header tanks and a big catching tank required as it will go at a fair rate I would have thought!

Edited by TVR Beaver on Thursday 8th April 08:14

[TVR Beaver]

BTW.. the standard bore on a 500 is 44mm from TVR... you gain 1mm... however it may (or may not) be ported better

[spend]

I think you are juggling 3 different areas, it is essential you define very specifically what you are talking about.

V8D prefer smaller cross-section between the inlet manifold & heads - which they find works best with their head porting. You can do wuite a lot to open up the head ports & inlet manifold, but they must match in philosophy as well as mating Sounds like Dom was talking more about the trumpet base - inlet manifold, thats generally where the 38/44/45mm figures apply (38mm std, 44mm 500, 45mm some specials, but you can get even bigger by making the ports non circular without trumpets). The other major area is the internal runners within the manifold which are cast 38mm, generally all you will see at best is the cast lines removed and flap wheel.. to smooth up, opening these ports up is very laborious & tricky.

I don't really understand if you're just asking for background knowledge, to evaluate what's available or trying to isolate your problems Richard. In case its the latter personally I would not have thought that any of the different offerings available would upset your cam to the extent of your problems?

[TVR Beaver]

Who's this Richard bloke?.. I'm John...



Anyways... Just wanting to know really... I've done a bit of porting on bikes when I raced them.. but nothing like this... The unit I have is 45mm to match the Ali trumpetts... and as you say, reduced towards the head end to give a faster flow as V8D prefer...
But with a bit of time and a flap wheel, what can be achieved... Is it time well spent getting these spot on one to the other.. and may be opening them up a bit?... or are we talking a few BHP gain that unless you have nothing else to do... is not worth the time??.. Just an interesting subject that's all