45mm inlet and Plenum base inc 72 mm throttle pot.
Discussion
phazed said:
I would have an educated guess.
Short stroke 5 L bottom end
Forged pistons and rods
72 mm plenum
Stealth camshaft
Stage four cylinder heads
Ported inlet manifold
45 mm short trumpet base
Camshaft timed slightly retarded to give Max bhp
I thank you
A nice shopping list. I agree with all of that. Short stroke 5 L bottom end
Forged pistons and rods
72 mm plenum
Stealth camshaft
Stage four cylinder heads
Ported inlet manifold
45 mm short trumpet base
Camshaft timed slightly retarded to give Max bhp
I thank you
Big everything the hp it’s got.
Great engine
So do I go blended base or shortened trumpets. Trumpets promote velocity but base promotes easy access to the air and a lot of it so the engine works less to suck it in. It’s far more complicated than that but that’s the jist if it.
Will a blended base work on the road as well as flat out at high revs?
Your thoughts on runner length please gentlemen.
Will a blended base work on the road as well as flat out at high revs?
Your thoughts on runner length please gentlemen.
Classic Chim said:
So do I go blended base or shortened trumpets. Trumpets promote velocity but base promotes easy access to the air and a lot of it so the engine works less to suck it in. It’s far more complicated than that but that’s the jist if it.
Will a blended base work on the road as well as flat out at high revs?
Your thoughts on runner length please gentlemen.
Phone Jools and ask him about the blended base. Ditto Peter. Jools sells them and is delightfully honest when assessing things that he sells. I think Peter fitted one, so can tell you if it made the blindest bit of difference. Will a blended base work on the road as well as flat out at high revs?
Your thoughts on runner length please gentlemen.
QBee said:
....as for runner length, 2/3rds of the length of your hall is about right, shows off the traditional parquet at the ends and sides just perfectly..... 
Do try to take this seriously you turbo boys at the back there! I’ve watched enough videos to find American Deep South lingo from good old boys bloody grating but also some good info on what to do. Roof Porting, higher revs
which is why V8D inlet and heads are the same I’ve spent about an hr or more just smoothing out one of the ports and those V8D heads and inlet are the nuts. So much work that whatever it cost it’s cheap!
I’m a bugger for keeping my head in the sand and maybe only motivation to make my car that bit better is what gets my engine firing enough to take notice.
Throughout all these videos various things usually come up.
Watching a few videos on inlet manifold theory and design has probably been the best for me to understand what I do and how it will effect how that air enters engine
Turbulence/ tumble and how air acts in a pipe cements the correct theories that porting should be employing.
The amount of standard Heads that can be improved by just finishing them off is crazy.
Movement of air in a pipe is one thing, when it is mixed with fuel quite another.
I have two known theories that contradict each other
1 says the head ports need to remain rough to promote swirl and keep fuel bouncing off the walls rather than running along them.
2 says sod that go for smooth inlet ports so keep promoting shoving the air and now fuel into the engine at high velocity and allowing the swirl to happen in the combustion chamber.
I like this second approach mainly because it goes against most people’s beliefs,,,
My question is will our combustion chamber design promote enough disturbance.
My own theory is if the air isn’t slowed up at the heads the injected fuel will be hitting faster travelling air so atomise well before it goes into chamber anyway.
I need to go to night school for all this stuff!
It’s going to take me weeks with my tooling but by f
k I’m going to have as smooth an air flow of any ported inlet going. The boundary layer can reduce the working air going though the centre of a pipe down to 80%
The rough casting of an RV8 inlet manifold on the outside probably gives you an idea of what it’s like through the runners.
If I run my finger along the port opening I’ve smoothed and then one that’s not,,, huge difference in friction
It’s gonna rip
Edited by Classic Chim on Saturday 17th March 13:00
My motivation for all this home tuning comes from a Tvr friend and owner with a fast car. I once asked rather quizzically why he rebuilt his own engine rather than go with one of the big boys, he just answered he couldn’t really justify the cost as he has a healthy family.
Quite logical really.
He has infact built, modified and repaired most of his car himself which is why he knows so much about it.
This has saved him enough money to track the car 4 times a year for free
What’s so exciting about porting is just the efficiency your creating which will never go away. Once it’s done it’s there forever. That’s like really valuable stuff!
After viewing so many videos from blokes with permanent black finger nails in machine shops who get good gains from simply making it all more efficient as the air travels in and out, the less restriction the more power as restrictions rob the engine of power using its own power sucking the stuff in then pushing it out again.
As we all know the Rover is starved by its head design.
All porting is doing is matching the best air intake speed for the engines power.
Exhaust porting is doing the exact same thing the other way but mainly getting gases out as fast as possible.
It’s not actually rocket science but getting it perfectly matched as in the math first is more challenging.
I’m fully understanding why twin and triple Plenum give fast engine response as there’s a huge amount of air just waiting to get in, less vacumn effect because of the extra butterflies so Engine doesn’t have to draw as hard on first acceleration and there’s less of an air pressure drop.
Twin planePlenum like ours also push more air back up the inlet tracts when inlet valves close so get the length wrong and there’s a an out of balance harmonic pulse effect that can work against you.
Your meant to be trying to get an even number of bounce so the bounce of air off the Plenum top back towards the inlet valve helps force air in as valve opens so your taking advantage of the pulse effect and added air speed.
How this really works at high revs and how or if these bounces can be calculated correctly seems another question.
There’s good math for this but worn cam chain could be enough to effect engines position as to effect this math.
Joolz blended base seems to employ a very different concept.
I will talk to him as they look great
Quite logical really.
He has infact built, modified and repaired most of his car himself which is why he knows so much about it.
This has saved him enough money to track the car 4 times a year for free
What’s so exciting about porting is just the efficiency your creating which will never go away. Once it’s done it’s there forever. That’s like really valuable stuff!
After viewing so many videos from blokes with permanent black finger nails in machine shops who get good gains from simply making it all more efficient as the air travels in and out, the less restriction the more power as restrictions rob the engine of power using its own power sucking the stuff in then pushing it out again.
As we all know the Rover is starved by its head design.
All porting is doing is matching the best air intake speed for the engines power.
Exhaust porting is doing the exact same thing the other way but mainly getting gases out as fast as possible.
It’s not actually rocket science but getting it perfectly matched as in the math first is more challenging.
I’m fully understanding why twin and triple Plenum give fast engine response as there’s a huge amount of air just waiting to get in, less vacumn effect because of the extra butterflies so Engine doesn’t have to draw as hard on first acceleration and there’s less of an air pressure drop.
Twin planePlenum like ours also push more air back up the inlet tracts when inlet valves close so get the length wrong and there’s a an out of balance harmonic pulse effect that can work against you.
Your meant to be trying to get an even number of bounce so the bounce of air off the Plenum top back towards the inlet valve helps force air in as valve opens so your taking advantage of the pulse effect and added air speed.
How this really works at high revs and how or if these bounces can be calculated correctly seems another question.
There’s good math for this but worn cam chain could be enough to effect engines position as to effect this math.
Joolz blended base seems to employ a very different concept.
I will talk to him as they look great
Edited by Classic Chim on Saturday 17th March 13:45
Edited by Classic Chim on Saturday 17th March 13:47
).It’s nerve wracking or it would be if it wasn’t a spare
I loved models as a boy, intricate fixing.
I need new glasses as you have to be so careful. I need a used die bit as one move and your trying to recover it!
This is sooo exciting, just push my finger along the small bit I’ve done and slides like on ice, that can’t be said when I do the same thing on the non ported one. I notice by taking more out the roof of the port and widening it you create a wider path past the injector, I’ve mimicked this idea a bit for practice. at this point air is coming in straight so more will get in off the port roof which promotes high revs apparently. They are all done this way so the theory must hold true here too.
This is the bit about cars I remember being into, bikes really, it’s time I fulfilled that desire and natural interest in how to make them faster via porting, which clearly works as has been proved by engine tuners for years. I’m just a Hobbyist who’s lucky enough to own a cheap V8 engine with an abundance of second hand parts around to learn with and more importantly lots of good Tvr friends who know all,about this stuff and can guide me to the right decisions. Heads heads aheads, I’m becomming obsessed by heads and there cool as feck
I loved models as a boy, intricate fixing.
I need new glasses as you have to be so careful. I need a used die bit as one move and your trying to recover it!
This is sooo exciting, just push my finger along the small bit I’ve done and slides like on ice, that can’t be said when I do the same thing on the non ported one. I notice by taking more out the roof of the port and widening it you create a wider path past the injector, I’ve mimicked this idea a bit for practice. at this point air is coming in straight so more will get in off the port roof which promotes high revs apparently. They are all done this way so the theory must hold true here too.
This is the bit about cars I remember being into, bikes really, it’s time I fulfilled that desire and natural interest in how to make them faster via porting, which clearly works as has been proved by engine tuners for years. I’m just a Hobbyist who’s lucky enough to own a cheap V8 engine with an abundance of second hand parts around to learn with and more importantly lots of good Tvr friends who know all,about this stuff and can guide me to the right decisions. Heads heads aheads, I’m becomming obsessed by heads and there cool as feck
carsy said:
Alun, i think gains will be minimal certainly not particularly noticeable on the standard heads.
Now if you were having the heads ported etc then i would say yes.
I have some heads available to work with. I’ll be matching all this together when they are all big valves and ported to stage 3 1/2 Now if you were having the heads ported etc then i would say yes.
72 mm Plenum and internally polished Plenum surface ( but still need to read more about this )
Blended or trumpets I’m still not decided but what do you think this might gain if done well and re mapped.
Can this gain me 25 hp as a combined unit.
I’m thinking Daz engine is so fast and high hp it must have stage 4 everything to do it, it’s as simple as that. High comp the other secret.
I digress
There’s obviously flow data for my engine as it’s tuned now.
By changing heads and complete intake system I’ll have some new data
To compare. Real evidence.
The beauty of after market Ecu and understanding how to read tuning software allows you to see the numbers.
What a great community we have.
I’ve had photos and loads of top class advice and feel quite confident.
So much so I’m thinking of adding a lump of weld and actually straightening out the wonky outside ports that are also longer by design. Joke,,,, watch this space. Maybe on the next one
I was going to take it all to Peters for us to poor over and get Si to give me a lesson in the dos and dont’s
I can easily see me ruining at least one manifold doing this. Hopefully by the time I get to heads I’ll have a feel for it.
It’s like painting,,,
The sound of a power tool doing work spins my wheels baby
I can easily see me ruining at least one manifold doing this. Hopefully by the time I get to heads I’ll have a feel for it.
It’s like painting,,,
The sound of a power tool doing work spins my wheels baby
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