Cerb 4.5 Airflow
Discussion
I've stared at my 4.5 engine a lot recently, maybe due to it sitting on sticks waiting for nitrons 
I can't help thinking the purple pipes going into the engine from the airbox are all wrong. I believe they must be causing a restriction to the airflow as they cross in the middle and feed between each other.
Assuming there isn't a reason they need to cross over, and that I could manufacture a constant diameter pipe that would not cross over but instead perform an S shape and connect to the same side airbox I would have achieved better cooling for the engine and I think I could achieve better airflow for the engine inlet.
Anyone tried this? Or have any comments?
I can't help thinking the purple pipes going into the engine from the airbox are all wrong. I believe they must be causing a restriction to the airflow as they cross in the middle and feed between each other.
Assuming there isn't a reason they need to cross over, and that I could manufacture a constant diameter pipe that would not cross over but instead perform an S shape and connect to the same side airbox I would have achieved better cooling for the engine and I think I could achieve better airflow for the engine inlet.
Anyone tried this? Or have any comments?
Julian, seeing as you're waiting for Nitrons why not let Tim at ACT have your inlets / pipes / airboxes .. we're looking for a car to rob some bits off for this very project .. feasability studies first ..
how about it? you can play a part in cerbera history?
lmao.
PS where are your nitrons coming from? ..
why not let Tim at ACT have your inlets / pipes / airboxes .. we're looking for a car to rob some bits off for this very project .. feasability studies first .. how about it? you can play a part in cerbera history?
lmao.
PS where are your nitrons coming from? ..
Julian,
If it ain't broke don't fix it.......otherwise it soon will be.
Trying to derive which shape of inlet will provide you with the best characteristics (either torque or high end power) will be a long and expensive effort for minimal return, for the same money get Joospeed et al, to do you an emerald chip. The results will be far easier to detect, Unless of course somebody is going to develop four valve heads with VVT and variable length inlet tracts?
Don't mean to appear negative, but why waste your money on time, I can appreciate how nice a carbon set of pipes would look though!!
If it ain't broke don't fix it.......otherwise it soon will be.
Trying to derive which shape of inlet will provide you with the best characteristics (either torque or high end power) will be a long and expensive effort for minimal return, for the same money get Joospeed et al, to do you an emerald chip. The results will be far easier to detect, Unless of course somebody is going to develop four valve heads with VVT and variable length inlet tracts?
Don't mean to appear negative, but why waste your money on time, I can appreciate how nice a carbon set of pipes would look though!!
joospeed said:
Julian, seeing as you're waiting for Nitrons
how about it? you can play a part in cerbera history?
lmao.
PS where are your nitrons coming from? ..
Where's ACT? If it was within shooting distance I would. Nitrons coming from Guy at nitrons. Very helpful chap. Was keen to order from you as you are the main reason I considered them in the first place but could never get hold of you. I believe you are going through your busy period at the mo. If you lived/worked near me I would be camped out on your front door step offering free help in exchange for instruction, priceless. I could even answer the phone for you "Hi its Julian"
I would love to take part in developing the cerb but wouldn't the feasibility study simply consist of removing airboxes and inlet pipes and seeing what the engine could produce naked? I thought the idea of inlet was nothing about tuning simply about protecting with the least resistance possible?
>> Edited by Julian64 on Tuesday 15th June 09:04
This idea has been floated before, but don't let that put you off!
The quickest/easiest way to achieve what you are looking for is to find some 4.2 inlets which are much shorter and more direct, they don't cross over either. This would be a good baseline. Then see if you can improve on this with different diameters/lengths of pipe (or whatever you had in mind).
Bear in mind you will need a very accurate dyno to detect any changes. Apparently Dynapack hub dynos are good for this as the results are very repeatable between runs.
Good Luck
Rob.
The quickest/easiest way to achieve what you are looking for is to find some 4.2 inlets which are much shorter and more direct, they don't cross over either. This would be a good baseline. Then see if you can improve on this with different diameters/lengths of pipe (or whatever you had in mind).
Bear in mind you will need a very accurate dyno to detect any changes. Apparently Dynapack hub dynos are good for this as the results are very repeatable between runs.
Good Luck
Rob.
Hold the fort!
Could someone explain to me why you require different inlet sizes or shapes. I understand the concept of tuned exhaust systems to create a standing wave for scavenging etc, but that has no application that I can think of in the inlet.
Surely the only function of the inlet is
1) let as much air in as possible with the least restriction
2) keep the air supply cool, another reason for not crossing the engine
3) Try to straighten pipes to maintain laminar flow to aid (1)
For these reasons the Cerb will never achieve as much power as when all the inlet stuff is removed and thrown in the bin? Apart from ram air effect which I think we can ignore whats left?
The compromise is filtering of the air to protect the engine and measuring air temp.
Could someone please enlighten me otherwise?
Could someone explain to me why you require different inlet sizes or shapes. I understand the concept of tuned exhaust systems to create a standing wave for scavenging etc, but that has no application that I can think of in the inlet.
Surely the only function of the inlet is
1) let as much air in as possible with the least restriction
2) keep the air supply cool, another reason for not crossing the engine
3) Try to straighten pipes to maintain laminar flow to aid (1)
For these reasons the Cerb will never achieve as much power as when all the inlet stuff is removed and thrown in the bin? Apart from ram air effect which I think we can ignore whats left?
The compromise is filtering of the air to protect the engine and measuring air temp.
Could someone please enlighten me otherwise?
This idea has been floated before, but don't let that put you off!
The quickest/easiest way to achieve what you are looking for is to find some 4.2 inlets which are much shorter and more direct, they don't cross over either. This would be a good baseline. Then see if you can improve on this with different diameters/lengths of pipe (or whatever you had in mind).
Bear in mind you will need a very accurate dyno to detect any changes. Apparently Dynapack hub dynos are good for this as the results are very repeatable between runs.
Good Luck
Rob.
The quickest/easiest way to achieve what you are looking for is to find some 4.2 inlets which are much shorter and more direct, they don't cross over either. This would be a good baseline. Then see if you can improve on this with different diameters/lengths of pipe (or whatever you had in mind).
Bear in mind you will need a very accurate dyno to detect any changes. Apparently Dynapack hub dynos are good for this as the results are very repeatable between runs.
Good Luck
Rob.
Julian64 said:
Hold the fort!
Could someone explain to me why you require different inlet sizes or shapes. Surely the only function of the inlet is..
Hmm. The variable inlet tracts on naturally aspirated BMWs and Volvos suggest otherwise. I presume pulse tuning for torque peaks is the name of the game, plus working with the combustion chamber shape to promote swirl, or laminar flow, depending on what they're trying to achieve.
How difficult would it be to replicate/modify the Tuscan racing setup? Presumably, they've done a lot of the hard work, if optimised for WOT.
>> Edited by Tam Lin on Tuesday 15th June 09:48
>> Edited by Tam Lin on Tuesday 15th June 09:51
Woah! Read any good book on tuning (e.g. Four-stroke Performance Tuning is great by
A.Graham Bell) - inlet tuning is as important as the exhaust in a high performance engine! Why else do you see specially shaped trumpets, or variably tuned length tracts - think of old racing cars all pointing up? It works in exactly the same way as the exhaust - you set up a standing wave with a positive point at the inlet valve. You generally want short tracts for power, longer for torque. The weird positioning of the throttle butterflies below the injector on the 4.5 doesn't help at lower revs - at higher revs it gives better fuel dispersion. If you pull off the tubes, you would see huge holes in the torque curve. The racing tuscans use straightish runners pointing straight up.
E.g. look at the trumpets on this www.raceline.co.uk/duratec.htm
A.Graham Bell) - inlet tuning is as important as the exhaust in a high performance engine! Why else do you see specially shaped trumpets, or variably tuned length tracts - think of old racing cars all pointing up? It works in exactly the same way as the exhaust - you set up a standing wave with a positive point at the inlet valve. You generally want short tracts for power, longer for torque. The weird positioning of the throttle butterflies below the injector on the 4.5 doesn't help at lower revs - at higher revs it gives better fuel dispersion. If you pull off the tubes, you would see huge holes in the torque curve. The racing tuscans use straightish runners pointing straight up.
E.g. look at the trumpets on this www.raceline.co.uk/duratec.htm
Okay, Okay, maybe standing wave in inlet tract, but before you go fine tuning the Cerb to race spec have you actually seen the restriction imposed by the layout. Surely this is far more important, and easily proved.
I still think much improvement would be gained by just taking the airboxes and inlet pipes off. Anyone got a dyno graph with inlets off to see where we stand?
I still think much improvement would be gained by just taking the airboxes and inlet pipes off. Anyone got a dyno graph with inlets off to see where we stand?
Julian
To be honest you are probably better of, looking at increasing the intake of air through forced induction. It will probably cost more to develop but power gains would be far better.
There was a company that provided electric fans for forced induction maybe this might be an avenue that could be linked into the engine management somehow? perhaps developed to fit prior to the air intake boxes. Whether you could achieve sufficent pressures (1- 2 bar) is debatable.
The bonnet space and exhuast arrangement don't really lend themselves to conventional turbos or superchargers.
I wish you all the luck in any developments you make, and let us all know any progress you make.
To be honest you are probably better of, looking at increasing the intake of air through forced induction. It will probably cost more to develop but power gains would be far better.
There was a company that provided electric fans for forced induction maybe this might be an avenue that could be linked into the engine management somehow? perhaps developed to fit prior to the air intake boxes. Whether you could achieve sufficent pressures (1- 2 bar) is debatable.
The bonnet space and exhuast arrangement don't really lend themselves to conventional turbos or superchargers.
I wish you all the luck in any developments you make, and let us all know any progress you make.
AAAAARARGGGGGGHHHHH, wheres the tearing whats left of your hair out smiley.
I'm not suggesting the car is run day to day without protection. Neither do I want to improve the power output of the engine with forced induction. God knows I can break the speed limit far too fast already. The trick (in my book) is to make what is there run properly.
What I am suggesting is that the current design of the airbox, inlet pipes is obviously flawed. If someone has ever run a Cerb on a dyno without these they would prove whether the obvious restriction imposed by the crossing and squeezing of pipes is a limiting factor to the engine or some sort of clever ingenious design for years of testing by TVR.
I know which one I'd put my money on.
I'm not suggesting the car is run day to day without protection. Neither do I want to improve the power output of the engine with forced induction. God knows I can break the speed limit far too fast already. The trick (in my book) is to make what is there run properly.
What I am suggesting is that the current design of the airbox, inlet pipes is obviously flawed. If someone has ever run a Cerb on a dyno without these they would prove whether the obvious restriction imposed by the crossing and squeezing of pipes is a limiting factor to the engine or some sort of clever ingenious design for years of testing by TVR.
I know which one I'd put my money on.
I see what you are getting at. Looking at the 4.2 engine over the weekend, i wondered the same thing. It has a lot of bends and curves in the inlet track, that cant be good for performance or efficiency.
What i would do is this;
Add these
With a nice sliding throttle assembly
A nice airbox mounted on top would sort the airflow out. Would be a good exercise, if not expensive!
What i would do is this;
Add these
With a nice sliding throttle assembly
A nice airbox mounted on top would sort the airflow out. Would be a good exercise, if not expensive!
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