For a turbo engine, how big is too big for an air intake? I know there's a point at which more flow won't help at all. How can I tell that point?
How big is too big for an air intake?
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How big an intake do you want?
OEMs put incredible time and effort into getting the acoustic properties of intakes such that they will maximize power in the rev range where NVH isn't too objectionable and transmissions can best utilize the power being produced. You will likely benefit from a larger intake no matter what, but unless you're willing to maintain the engine above 4000 rpm at all times (for instance), there's not much sense in going too big.
OEMs put incredible time and effort into getting the acoustic properties of intakes such that they will maximize power in the rev range where NVH isn't too objectionable and transmissions can best utilize the power being produced. You will likely benefit from a larger intake no matter what, but unless you're willing to maintain the engine above 4000 rpm at all times (for instance), there's not much sense in going too big.
These days the throttle body is already in control of the air volume admitted to the motor. On most turbos the wastegate and/or downpipe is a common choke point.
The point at which no more flow is possible is zero inches of mercury, an unattainable goal. Measured inside the air intake tube at full throttle.
I'd simply peruse the forums and use what other owners with the same car use.
The point at which no more flow is possible is zero inches of mercury, an unattainable goal. Measured inside the air intake tube at full throttle.
I'd simply peruse the forums and use what other owners with the same car use.
Too big and the flow speed and quality drops (turbulence). Too small and the engine is being starved.
Same principles apply to exhaust tubing.
Same principles apply to exhaust tubing.
Your turbo on the 1.4 is most likely done before the intake is limiting. IF you have and maintain nominal boost on the turbo up to 4500-5000rpm its getting all the air it needs. First tweek on a turbo street car would be a muffler delete with a straight-through pipe or non-limiting resonator. Under boost, the turbo will convert most all the exhaust energy, so there is not much din to quell. Does the GM 1.4 ecotec turbo have a intercooler?
I just read steves reply he is hinting at pressure drop through the system - if you can adapt a gauge on your airbox you could see if its running a moderate vacuum. Some guys cut holes in the airbox, If I did that I would put a flapper valve internally over the hole so it would only open under moderate vacuum +. Carefull as water managment can be a big problem.
I just read steves reply he is hinting at pressure drop through the system - if you can adapt a gauge on your airbox you could see if its running a moderate vacuum. Some guys cut holes in the airbox, If I did that I would put a flapper valve internally over the hole so it would only open under moderate vacuum +. Carefull as water managment can be a big problem.
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Originally Posted By: ARCOgraphite
Your turbo on the 1.4 is most likely done before the intake is limiting. IF you have and maintain nominal boost on the turbo up to 4500-5000rpm its getting all the air it needs. First tweek on a turbo street car would be a muffler delete with a straight throuh pipe or non limiting resonator. Under boost the turbo will take all the exhaust energy so there is not much din to quell. Does the GM 1.4 ecotec turbo have a intercooler?
Yes, it's intercooled.
I'm not interested in a traditional cold air intake since it's too noisy. I've heard them on the Cruze's turbo engine, and they're not my cup of tea.
It's more of a "Hmm, why is it like it is?" question. Also, the K&N intake re-uses part of the stock piping. The OEM stuff can't be that bad if part of it is re-used.
Your turbo on the 1.4 is most likely done before the intake is limiting. IF you have and maintain nominal boost on the turbo up to 4500-5000rpm its getting all the air it needs. First tweek on a turbo street car would be a muffler delete with a straight throuh pipe or non limiting resonator. Under boost the turbo will take all the exhaust energy so there is not much din to quell. Does the GM 1.4 ecotec turbo have a intercooler?
Yes, it's intercooled.
I'm not interested in a traditional cold air intake since it's too noisy. I've heard them on the Cruze's turbo engine, and they're not my cup of tea.
It's more of a "Hmm, why is it like it is?" question. Also, the K&N intake re-uses part of the stock piping. The OEM stuff can't be that bad if part of it is re-used.
The TB and airflow sensor are two chokes in the system.
So are bends.
Tiny inlet snorkels on decent pipes ruin everything.
Tumorous appendages on the intake suppress noise, but hurt flow.
So how big a pipe? No one makes one too big, although we can cobble up something that would
hurt MAF readings on transients. At full throttle, bigger is generally better.
So are bends.
Tiny inlet snorkels on decent pipes ruin everything.
Tumorous appendages on the intake suppress noise, but hurt flow.
So how big a pipe? No one makes one too big, although we can cobble up something that would
hurt MAF readings on transients. At full throttle, bigger is generally better.
OVERKILL
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It is a 1.4L engine, it doesn't need "big rig" piping. What is factory is likely more than adequate.
There seems to be room for improvement for those who don't mind the extra noise and inferior filtration. The K&N dyno sheet shows a pretty big gain with their intake across the entire rev range; up to 6.5 HP and 9.5 lb-ft at the wheels.
http://www.knfilters.com/dynocharts/69-4521_dyno.pdf
I don't know how much the filter itself contributes to that.
http://www.knfilters.com/dynocharts/69-4521_dyno.pdf
I don't know how much the filter itself contributes to that.
OVERKILL
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Originally Posted By: rpn453
There seems to be room for improvement for those who don't mind the extra noise and inferior filtration. The K&N dyno sheet shows a pretty big gain with their intake across the entire rev range; up to 6.5 HP and 9.5 lb-ft at the wheels.
http://www.knfilters.com/dynocharts/69-4521_dyno.pdf
I don't know how much the filter itself contributes to that.
Pretty big gain and 6.5HP don't belong in the same sentence
There seems to be room for improvement for those who don't mind the extra noise and inferior filtration. The K&N dyno sheet shows a pretty big gain with their intake across the entire rev range; up to 6.5 HP and 9.5 lb-ft at the wheels.
http://www.knfilters.com/dynocharts/69-4521_dyno.pdf
I don't know how much the filter itself contributes to that.
Pretty big gain and 6.5HP don't belong in the same sentence
Many intakes only replace the first half of the piping or less. That allows them to adapt a conical filter, but there is still restriction left from the OE pieces in many cases.
I would recommend a cheap intake that comes with a good heat shield, and then get some universal silicone hose/tubing that is pre-bent where needed, and silicone.couplers, and replace the rest of the OE tubing up to the throttle body with that. It can be done for $40 if you go with good quality, 4ply silicone piping.
Then wrap all of it in insulating wrap, the exhaust wrap works fine if you then cover it with reflective aluminum tape.
The difference was significant in my case, as 90degree bends were smoothed out to 45 degree ones, and it is quite clear visually that it is a much smoother path. I also used a quality temp resistant coating on the entirety of it, and the heat shield too.
It dropped intake air temp significantly, with the air being barely above ambient. Just the tubing proved to provide an additional 3rwhp on a naturally aspirated car, with double that after everything was isolated from engine bay heat. Of course, now it is hard to tell because the major heat makers in my engine no longer put out that kind of heat (ceramic headers, intake manifold, valves, etc all Swaintech coated and cats removed), so underhood temps are very low.
On a turbo car, I would consider getting one of those turbo covers that prevents heat from transferring to or from the rest of the engine bay. I do not know much about that, but I know people who have had their entire turbos Swaintech coated and with very good results.
I would recommend a cheap intake that comes with a good heat shield, and then get some universal silicone hose/tubing that is pre-bent where needed, and silicone.couplers, and replace the rest of the OE tubing up to the throttle body with that. It can be done for $40 if you go with good quality, 4ply silicone piping.
Then wrap all of it in insulating wrap, the exhaust wrap works fine if you then cover it with reflective aluminum tape.
The difference was significant in my case, as 90degree bends were smoothed out to 45 degree ones, and it is quite clear visually that it is a much smoother path. I also used a quality temp resistant coating on the entirety of it, and the heat shield too.
It dropped intake air temp significantly, with the air being barely above ambient. Just the tubing proved to provide an additional 3rwhp on a naturally aspirated car, with double that after everything was isolated from engine bay heat. Of course, now it is hard to tell because the major heat makers in my engine no longer put out that kind of heat (ceramic headers, intake manifold, valves, etc all Swaintech coated and cats removed), so underhood temps are very low.
On a turbo car, I would consider getting one of those turbo covers that prevents heat from transferring to or from the rest of the engine bay. I do not know much about that, but I know people who have had their entire turbos Swaintech coated and with very good results.
It's not likely that any component of the intake system is small enough to create a restriction for that tiny turbo. Quite simply, that turbo will simply spin a few hundred or thousand RPM more to overcome any inherent restriction.
Sure, compressor and turbine efficiency is slightly reduced. But the overall effect on output will probably be immeasurable.
You can illustrate this with a conventional "old school" turbo car, (throttle by cable) by getting on boost at half throttle. The turbo will simply push air around the throttle plate and more opening won't result in much more power.
It really is interesting to see how much a throttle plate can close down and still produce plenty of power when under boost. In the dyno room, it becomes quite clear.
Remember though, that when not under boost, the above does not apply.
Sure, compressor and turbine efficiency is slightly reduced. But the overall effect on output will probably be immeasurable.
You can illustrate this with a conventional "old school" turbo car, (throttle by cable) by getting on boost at half throttle. The turbo will simply push air around the throttle plate and more opening won't result in much more power.
It really is interesting to see how much a throttle plate can close down and still produce plenty of power when under boost. In the dyno room, it becomes quite clear.
Remember though, that when not under boost, the above does not apply.
you cats hurt my brain.
Originally Posted By: OVERK1LL
Pretty big gain and 6.5HP don't belong in the same sentence
Hey, that would be a HUGE gain on a shifter kart!
Pretty big gain and 6.5HP don't belong in the same sentence
Hey, that would be a HUGE gain on a shifter kart!
Originally Posted By: rpn453
There seems to be room for improvement for those who don't mind the extra noise and inferior filtration. The K&N dyno sheet shows a pretty big gain with their intake across the entire rev range; up to 6.5 HP and 9.5 lb-ft at the wheels.
http://www.knfilters.com/dynocharts/69-4521_dyno.pdf
I don't know how much the filter itself contributes to that.
6.5 hp isn't noticeable, even at WOT.
I figured that Chevy would have done a good job with the factory intake. I can't fathom spending $300-400 for a conical air filter, some aluminum pipe, and a few rubber couplers. Not unless there's a massive gain in hp/torque.
There seems to be room for improvement for those who don't mind the extra noise and inferior filtration. The K&N dyno sheet shows a pretty big gain with their intake across the entire rev range; up to 6.5 HP and 9.5 lb-ft at the wheels.
http://www.knfilters.com/dynocharts/69-4521_dyno.pdf
I don't know how much the filter itself contributes to that.
6.5 hp isn't noticeable, even at WOT.
I figured that Chevy would have done a good job with the factory intake. I can't fathom spending $300-400 for a conical air filter, some aluminum pipe, and a few rubber couplers. Not unless there's a massive gain in hp/torque.
Originally Posted By: sciphi
6.5 hp isn't noticeable, even at WOT.
Maybe not to you, but a Formula1 team would pay millions to add another 6.5 hp to the 700+ they already have!
I think having 13% more power at 3000 rpm may be noticeable. That's the biggest and most usable power improvement I can remember seeing for any aftermarket intake or exhaust.
6.5 hp isn't noticeable, even at WOT.
Maybe not to you, but a Formula1 team would pay millions to add another 6.5 hp to the 700+ they already have!
I think having 13% more power at 3000 rpm may be noticeable. That's the biggest and most usable power improvement I can remember seeing for any aftermarket intake or exhaust.
Originally Posted By: rpn453
Originally Posted By: sciphi
6.5 hp isn't noticeable, even at WOT.
Maybe not to you, but a Formula1 team would pay millions to add another 6.5 hp to the 700+ they already have!
I think having 13% more power at 3000 rpm may be noticeable. That's the biggest and most usable power improvement I can remember seeing for any aftermarket intake or exhaust.
In that context, it is actually pretty good for an intake.
Originally Posted By: sciphi
6.5 hp isn't noticeable, even at WOT.
Maybe not to you, but a Formula1 team would pay millions to add another 6.5 hp to the 700+ they already have!
I think having 13% more power at 3000 rpm may be noticeable. That's the biggest and most usable power improvement I can remember seeing for any aftermarket intake or exhaust.
In that context, it is actually pretty good for an intake.
Forget K&N power claims. They are complete bunk.
And 6 hp is within the margin of error on most any dyno that's not mounted in a lab!
And 6 hp is within the margin of error on most any dyno that's not mounted in a lab!
Turbo charged motors don't care. If you have a restricted intake they just take a bit longer to spool up.
As for to big no such thing.
As for to big no such thing.
Originally Posted By: SteveSRT8
Forget K&N power claims. They are complete bunk.
And 6 hp is within the margin of error on most any dyno that's not mounted in a lab!
Yeah, they could be doing it drug-company style: keep doing studies until you get one that barely shows a statistically significant benefit, and then publish only that one!
Is 6 hp a typical random error or systematic error? Those machines would have to be of extremely poor design or quality to have such a large random error.
I would like to hear more about disproven K&N power claims if you have any info. Most of their claims seem pretty reasonable.
Forget K&N power claims. They are complete bunk.
And 6 hp is within the margin of error on most any dyno that's not mounted in a lab!
Yeah, they could be doing it drug-company style: keep doing studies until you get one that barely shows a statistically significant benefit, and then publish only that one!
Is 6 hp a typical random error or systematic error? Those machines would have to be of extremely poor design or quality to have such a large random error.
I would like to hear more about disproven K&N power claims if you have any info. Most of their claims seem pretty reasonable.
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