45mm inlet and Plenum base inc 72 mm throttle pot.
Discussion
|https://thumbsnap.com/ZgueOk3n[/url
Started cleaning up my manifold with a wire brush attatchrment on my battery gun and 15 mins later 
I was going to paint it but have some small attachments I can use so might aswell buff the alloy up. This is being ported out at some stage so not going over the top but what fun
Should look superb with Plenum etc to match, if your into clean polished metal engine art as I call it this is one whole heap of fun
I was going to paint it but have some small attachments I can use so might aswell buff the alloy up. This is being ported out at some stage so not going over the top but what fun
Should look superb with Plenum etc to match, if your into clean polished metal engine art as I call it this is one whole heap of fun
Edited by Classic Chim on Saturday 10th March 20:28
QBee said:
Is that the high temperature version of Pave Fix plus, that you are using to seal the plenum on?
There are two types, the British type and the one for hot climates, where you can fry an egg on the pavement - you need the latter I think.
I knew you’d be on me like a flash There are two types, the British type and the one for hot climates, where you can fry an egg on the pavement - you need the latter I think.
Makes a good seat as I was only staring at the manifold and decided to try with the drill just to see,,,, well chuffed, off to buy more attachments
What he says ^^^^^ this will make little difference without bigger heads.
Two hours with cheap throw away drill attachments and it’s starting to look ok.
You can see the contrast in colours from the Trumpet base and thermostat housing.
Better light
Two hours with cheap throw away drill attachments and it’s starting to look ok.
You can see the contrast in colours from the Trumpet base and thermostat housing.
Better light
Edited by Classic Chim on Saturday 10th March 20:24
QBee said:
Takes a real enthusiast to brag about his small attachment 
See you both on Saturday. I will be bringing a bag of bits to fit and some tools. Got to keep myself occupied while you two talk diffs.....
Can’t wait to see these tools See you both on Saturday. I will be bringing a bag of bits to fit and some tools. Got to keep myself occupied while you two talk diffs.....
If anything like mine they will be full on Mickey Mouse.
I might bring my CupraR spoiler if I haven’t fitted it first.
The idea is to slam Peters car together so we have access to the lift
I better get there early doors then
No probs.
I’ve just read on another thread saying you get a lot more torque with ported heads,,,, interesting as I do like torque.
Something that sort of concerns me about going to 45 mm inlet tract is how the air is going to be slower at low revs and with less pressure, high air speed = Better atomisation.
Or am I just freeing up the air to actually speed in faster. Looking at the inlet ports on the manifold it seems all I’m doing is increasing the size quite marginally in essence and straightening out the flow to the heads where I can. Reading about how fuel and air travel it’s obvious you just want a consistent straight line from trumpets to heads as best you can get it. Smoothing out the flow is probably as important as opening up the size.
Tracts 1 and 8 on the manifold look like the ones that need the most work as it’s like an S bend. I’ve been Looking at how thick the casting is as I know Simon went to far on one.
As little as 3 mm to play with but about 5 mm thick in places so,that sort of governs what I can do. Just shine a torch down the inlet ports and it’s easy to see 1 and 8 are not good.
I’m also feeling this is a waste without porting the heads to a decent size as that seems to be where the big restriction actually is then matching the inlet manifold to the heads.
We’ll see
I’ve just read on another thread saying you get a lot more torque with ported heads,,,, interesting as I do like torque.
Something that sort of concerns me about going to 45 mm inlet tract is how the air is going to be slower at low revs and with less pressure, high air speed = Better atomisation.
Or am I just freeing up the air to actually speed in faster. Looking at the inlet ports on the manifold it seems all I’m doing is increasing the size quite marginally in essence and straightening out the flow to the heads where I can. Reading about how fuel and air travel it’s obvious you just want a consistent straight line from trumpets to heads as best you can get it. Smoothing out the flow is probably as important as opening up the size.
Tracts 1 and 8 on the manifold look like the ones that need the most work as it’s like an S bend. I’ve been Looking at how thick the casting is as I know Simon went to far on one.
As little as 3 mm to play with but about 5 mm thick in places so,that sort of governs what I can do. Just shine a torch down the inlet ports and it’s easy to see 1 and 8 are not good.
I’m also feeling this is a waste without porting the heads to a decent size as that seems to be where the big restriction actually is then matching the inlet manifold to the heads.
We’ll see
Edited by Classic Chim on Wednesday 14th March 00:01
The answer from my end is I don’t rightly know and so I’ll be asking some VIP’s for advice.
Clearly if you bore out the Plenum base and also the inlet tracts to 45 mm you now have a step in the inlet so that will need smoothing out. There’s not enough meat to take each tract to 45 mm along its complete length so just a smoothing out and matching at the heads which might be to open the ports on the inlets a bit so they match with no steps. They start big at the Plenum and get smaller as they go towards the heads which will increase air speed, it’s all about atomisation and the perfect mix at the end of the day. I don’t want to effect that to much but the ports are the restriction. I can’t do much about that without first opening up the head ports so as to make the inlet ports bigger to match.
I can see why people warn this alone will not make any real difference to performance as there’s not a huge amount you can remove from the inlet tracts without breaching them.
I’ve not decided on what tooling to use but yes something like a bremmel to just slowly shave bits off.
This is something of a long term goal as I’ve only just got the manifold and it’s just something extra to play with when I’m bored.
I’m likely to get the boring done at the Plenum end then wait until I can afford to do the heads then finish off the manifold to suit big ports that end.
It doesn't take a genius once you have a manifold off the car to work out where it meets the heads is the bottle neck as that’s where it’s at it’s narrowest and twists and turns as it goes. Other than two ports they are pretty straight and direct so very little you can actually do with them, just enlarge them slightly keeping to the original design, they narrow a bit then open up at the heads so again without big ported heads the gain will me minimalised.
I’ve more to read!!!
Clearly if you bore out the Plenum base and also the inlet tracts to 45 mm you now have a step in the inlet so that will need smoothing out. There’s not enough meat to take each tract to 45 mm along its complete length so just a smoothing out and matching at the heads which might be to open the ports on the inlets a bit so they match with no steps. They start big at the Plenum and get smaller as they go towards the heads which will increase air speed, it’s all about atomisation and the perfect mix at the end of the day. I don’t want to effect that to much but the ports are the restriction. I can’t do much about that without first opening up the head ports so as to make the inlet ports bigger to match.
I can see why people warn this alone will not make any real difference to performance as there’s not a huge amount you can remove from the inlet tracts without breaching them.
I’ve not decided on what tooling to use but yes something like a bremmel to just slowly shave bits off.
This is something of a long term goal as I’ve only just got the manifold and it’s just something extra to play with when I’m bored.
I’m likely to get the boring done at the Plenum end then wait until I can afford to do the heads then finish off the manifold to suit big ports that end.
It doesn't take a genius once you have a manifold off the car to work out where it meets the heads is the bottle neck as that’s where it’s at it’s narrowest and twists and turns as it goes. Other than two ports they are pretty straight and direct so very little you can actually do with them, just enlarge them slightly keeping to the original design, they narrow a bit then open up at the heads so again without big ported heads the gain will me minimalised.
I’ve more to read!!!
Edited by Classic Chim on Wednesday 14th March 14:08
Good idea as I need to know one way or another.
I believe the valves are the biggest Rover installed so somewhere in between standard and big valve but possibly just 4.0 spec for all I know.
I don’t believe there’s any porting as Tvr Power didn’t bother with that on the late 4.6 engines.
By the year 2000 when mine was built it was a crate engine and just a cam change I think.
Dom says Rover had taken notice of the gains tuners like himself and others were making and did better the heads but that’s just hearsay as far as I’m concerned.
I’m fully expecting standard heads other than the lapping in and steel rockers Dom fitted.
I do want to find out ASAP so I can plan this out better
I believe the valves are the biggest Rover installed so somewhere in between standard and big valve but possibly just 4.0 spec for all I know.
I don’t believe there’s any porting as Tvr Power didn’t bother with that on the late 4.6 engines.
By the year 2000 when mine was built it was a crate engine and just a cam change I think.
Dom says Rover had taken notice of the gains tuners like himself and others were making and did better the heads but that’s just hearsay as far as I’m concerned.
I’m fully expecting standard heads other than the lapping in and steel rockers Dom fitted.
I do want to find out ASAP so I can plan this out better
It’s just dawned on me you can only enlarge the inlet manifold ports to the size of the biggest inlet valley gasket you can get.
So enlarged head ports can only go to this also at the gasket point!
Let’s find a reason to pull Peters heads so I can take measurements and observations as to where to chop out
So enlarged head ports can only go to this also at the gasket point!
Let’s find a reason to pull Peters heads so I can take measurements and observations as to where to chop out
Sardonicus said:
any of the 450 model Chimaera's came with the bigger 500 spec valves but very little porting work just around the pockets to accommodate the larger valve seats 
but you know what TVR are like 
I’d like to think thats true in my case but I’m not holding my breath. but you know what TVR are like My dyno graph suggests 275-285hp Catted which is not setting the times alight
Ok if I add 17% road train loss I get 299 hp from my at the wheels figure but that’s not very realistic.
It’s probably around the 305 hp mark de Cat as otherwise how would I have done a 12.7 on road tyres!
I’m thinking with a serious of what defo becomes expensive mods I can get to 320 de Cat.
If I can gain a little more torque then I’m pushing past 345/360 depending on how you calc road train loss which combined should make it seem even faster than it is.
My torque figure suggests good compression but my hp figure suggests it needs more air to really fly
It’s just a lot of fun thinking about it all let alone trying to become the next tuning guru
Based on manifold gasket sizes and stretching that another 1mm all round this is roughly the size I’ll be going to if my heads are at least this size.
The original port holes are 23x38mm
The largest gasket Powers do is about 26x44mm and So that's the size I’ve scribbled.
To my untrained eye but looking at how air travels through the manifold it looks to me I’ll have more gain by employing the porting on the left of the picture.
And it’s easier. Sardonicus has kindly already pointed out on another thread there’s very little meat where the inj comes through so other than a bit of a ridge to smooth out I’d like to stay well clear of that area.
Thoughts please tuners
The original port holes are 23x38mm
The largest gasket Powers do is about 26x44mm and So that's the size I’ve scribbled.
To my untrained eye but looking at how air travels through the manifold it looks to me I’ll have more gain by employing the porting on the left of the picture.
And it’s easier. Sardonicus has kindly already pointed out on another thread there’s very little meat where the inj comes through so other than a bit of a ridge to smooth out I’d like to stay well clear of that area.
Thoughts please tuners
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