Can The Fd's Have An Intake Test
01-26-02, 11:19 PM
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Can The Fd's Have An Intake Test
Just want to know if a intake test was done for the RX7TT , i have seen them done for the supra,skyline,civic,ect. Can the RX7TT get some love, someone posted a really good one but it was tested for the supra. help i like the LM blitz. apexi, and m2 intake. please help if you have know of a link for the fd
01-26-02, 11:54 PM
#2
There's been a lot of debate on here about cold intakes verse open air intakes.
I can't remember who it was, but someone posted up about the air heating up anyways after the intake took it, so the cold air intakes didn't really give you that much of a benefit. The intercooler is where you really need the cold air.
As far as the intakes, generally, non-foam filters filter better however when the filter is dirty, performance is restricted much more than a foam filter intake (read some articles about that somewhere). The foam filter intakes will require much more care as you'll need to change the filter about every 2500-3000 miles since they don't filter as well and get dirty quite easily. I change mine with every oil change. Apexi seems to have the cleanest filtering intake, however that's really only based on one test that's been floating around the net.
They all provide about the same power increase, so go with the one you like the best. Personally, I think the Blitz intake "looks" the best under the hood, but unfortunately, it was on back order when I went to purchase mine.
I can't remember who it was, but someone posted up about the air heating up anyways after the intake took it, so the cold air intakes didn't really give you that much of a benefit. The intercooler is where you really need the cold air.
As far as the intakes, generally, non-foam filters filter better however when the filter is dirty, performance is restricted much more than a foam filter intake (read some articles about that somewhere). The foam filter intakes will require much more care as you'll need to change the filter about every 2500-3000 miles since they don't filter as well and get dirty quite easily. I change mine with every oil change. Apexi seems to have the cleanest filtering intake, however that's really only based on one test that's been floating around the net.
They all provide about the same power increase, so go with the one you like the best. Personally, I think the Blitz intake "looks" the best under the hood, but unfortunately, it was on back order when I went to purchase mine.
01-27-02, 04:28 AM
#3
Originally posted by Mahjik
I can't remember who it was, but someone posted up about the air heating up anyways after the intake took it, so the cold air intakes didn't really give you that much of a benefit. The intercooler is where you really need the cold air.
I can't remember who it was, but someone posted up about the air heating up anyways after the intake took it, so the cold air intakes didn't really give you that much of a benefit. The intercooler is where you really need the cold air.
There is some info about intakes (including temp tests, IIRC) on ScuderiaCiriani.com:
http://www.scuderiaciriani.com/rx7/intake.html
-Max
01-27-02, 05:15 AM
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Im partial towards open air intakes...the cold air boxes tend to really restrict your choice of intercooler and radiator because of their size. You could always try to duct more cold air into the engine bay, get a vented hood, take out the dp, among others to keep underhood temps down so you can suck in cooler air.
01-27-02, 07:02 AM
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Thanks for the info, the pepole at BLITZ said that there LM intake was even better than there older version, IT was rated at 16hp the most out of any intake. I dont know, have you guys ever heard of it? And as far as the M2 intake, Im really thinking about getting that one but a guy on the forum said that it may not work with the apexi front mount IC, i thouht that i was halfte size of the stock intake.
01-27-02, 12:18 PM
#7
What Max said is right. Whatever you can do to decrease the air temperature at the intake port will help power. Where you take the heat out matters a little, but not much. In other words, a 10-degree decrease after the air filter will mean almost a 10-degree decrease at the intake port, regardless of how much the turbo increases the temperature, or how much the intercooler decreases it.
Originally posted by eitan
I was under the impression that with a turbo setup cold air intake setups are unecessary because once the air passes the turbo wheel it heats up anyway.
I was under the impression that with a turbo setup cold air intake setups are unecessary because once the air passes the turbo wheel it heats up anyway.
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01-27-02, 01:50 PM
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So basicaly it sounds like the M2 intake would be my best choice
. do you guys know of anyone with the M2 intake and afront munt IC being used.
. do you guys know of anyone with the M2 intake and afront munt IC being used.
01-27-02, 03:28 PM
#9
Here's a quote from the thread I was referring to:
So, will the cold air be worth the extra money? Depends on you... Personally, I would save the extra cash from the cold air intake and use it towards an upgraded intercooler.
Originally posted by 7 eleven
Colder is always better, But at what price ? In a turbo Car the intake temp To the inlet side of the Turbo is Not very important compared to a NA Car. When you compress air it heats up, Right? I 'm sure one agrees here. The part most miss is that it is not proportional. For example it the turbo takes in 70 degree air and compresses it to X psi it will heat it up to say 110 degrees. Now say it takes in 30 degree air, Your thinking ok 70 - 30 = -40 degrees from the 110 degrees so it's now down to 70 degrees and rule of thumb is 11 degrees equal 1% increase in output so a Lightly modded 7 making 300hp gets roughly a 9hp(Of course you get some hp due to less restrictive filters but open filters get that to so it equals out) increase due to the (NO names here) say 485 dollar intake. You pat yourself on the back and show it off to your friends, right? Well if only you got that much bang for your bucks.
When air is compressed by a turbo it's a nasty messy affair, so your Cold 30 degree air is heated to within say 10 degrees of the Hot 70 degree air on the outlet side of the turbo. So now your 9hp gain is a 3hp gain and you could have got a 200 dollar intake and blow the other 285 on strippers or what ever. At least that way you could tell every body you spent 285 on strippers and feel better than saying you paid 285 on 3hp.
Sorry it was so long but hey it's free.
Colder is always better, But at what price ? In a turbo Car the intake temp To the inlet side of the Turbo is Not very important compared to a NA Car. When you compress air it heats up, Right? I 'm sure one agrees here. The part most miss is that it is not proportional. For example it the turbo takes in 70 degree air and compresses it to X psi it will heat it up to say 110 degrees. Now say it takes in 30 degree air, Your thinking ok 70 - 30 = -40 degrees from the 110 degrees so it's now down to 70 degrees and rule of thumb is 11 degrees equal 1% increase in output so a Lightly modded 7 making 300hp gets roughly a 9hp(Of course you get some hp due to less restrictive filters but open filters get that to so it equals out) increase due to the (NO names here) say 485 dollar intake. You pat yourself on the back and show it off to your friends, right? Well if only you got that much bang for your bucks.
When air is compressed by a turbo it's a nasty messy affair, so your Cold 30 degree air is heated to within say 10 degrees of the Hot 70 degree air on the outlet side of the turbo. So now your 9hp gain is a 3hp gain and you could have got a 200 dollar intake and blow the other 285 on strippers or what ever. At least that way you could tell every body you spent 285 on strippers and feel better than saying you paid 285 on 3hp.
Sorry it was so long but hey it's free.
01-27-02, 03:47 PM
#10
7 eleven overstates the losses. You won't get 100% of the pre-compression temperature difference into the engine, but you'll get much more than 25% of it.
Originally posted by Mahjik
Here's a quote from the thread I was referring to:
So, will the cold air be worth the extra money? Depends on you... Personally, I would save the extra cash from the cold air intake and use it towards an upgraded intercooler.
Here's a quote from the thread I was referring to:
Originally posted by 7 eleven
Colder is always better, But at what price ? In a turbo Car the intake temp To the inlet side of the Turbo is Not very important compared to a NA Car. When you compress air it heats up, Right? I 'm sure one agrees here. The part most miss is that it is not proportional. For example it the turbo takes in 70 degree air and compresses it to X psi it will heat it up to say 110 degrees. Now say it takes in 30 degree air, Your thinking ok 70 - 30 = -40 degrees from the 110 degrees so it's now down to 70 degrees and rule of thumb is 11 degrees equal 1% increase in output so a Lightly modded 7 making 300hp gets roughly a 9hp(Of course you get some hp due to less restrictive filters but open filters get that to so it equals out) increase due to the (NO names here) say 485 dollar intake. You pat yourself on the back and show it off to your friends, right? Well if only you got that much bang for your bucks.
When air is compressed by a turbo it's a nasty messy affair, so your Cold 30 degree air is heated to within say 10 degrees of the Hot 70 degree air on the outlet side of the turbo. So now your 9hp gain is a 3hp gain and you could have got a 200 dollar intake and blow the other 285 on strippers or what ever. At least that way you could tell every body you spent 285 on strippers and feel better than saying you paid 285 on 3hp.
Sorry it was so long but hey it's free.
Colder is always better, But at what price ? In a turbo Car the intake temp To the inlet side of the Turbo is Not very important compared to a NA Car. When you compress air it heats up, Right? I 'm sure one agrees here. The part most miss is that it is not proportional. For example it the turbo takes in 70 degree air and compresses it to X psi it will heat it up to say 110 degrees. Now say it takes in 30 degree air, Your thinking ok 70 - 30 = -40 degrees from the 110 degrees so it's now down to 70 degrees and rule of thumb is 11 degrees equal 1% increase in output so a Lightly modded 7 making 300hp gets roughly a 9hp(Of course you get some hp due to less restrictive filters but open filters get that to so it equals out) increase due to the (NO names here) say 485 dollar intake. You pat yourself on the back and show it off to your friends, right? Well if only you got that much bang for your bucks.
When air is compressed by a turbo it's a nasty messy affair, so your Cold 30 degree air is heated to within say 10 degrees of the Hot 70 degree air on the outlet side of the turbo. So now your 9hp gain is a 3hp gain and you could have got a 200 dollar intake and blow the other 285 on strippers or what ever. At least that way you could tell every body you spent 285 on strippers and feel better than saying you paid 285 on 3hp.
Sorry it was so long but hey it's free.
01-27-02, 05:12 PM
#11
Whether a cool air intake is worth the money and packaging problems will always be a decision that the buyer has to make for themselves, but it is important to know the effects of hotter intake air in making that decision.
We haven't accounted for all the effects yet. So here is my stab at what happens when the intake temp increases:
If your intake air is 30F hotter, your intake charge will be 30F hotter coming out of the compressor. Because the air is hotter relative to the outside air flowing through the intercooler, the IC efficiency will nominally increase. Since the IC removes more heat, you might only get a 10F or 15F increase in intake temp as a result of 30F hotter intake air at the compressor inlet. I would be interested to hear of any measurements people have done of these temps, to check our assumptions. This is the issue that has already been raised, hopefully made a little more clear with my description.
One effect not yet accounted for is that the cost of increased efficiency in the IC is a slight increase in pressure drop. To make up for the increased pressure drop, the compressor has to compress the air a little more, which both makes the compressor outlet air even hotter and also increases the backpressure. The backpressure fights the incoming intake charge, making it a little hotter and a little less dense with oxygen when it finally gets into the combustion chamber. Backpressure also results in less flow through the engine, so you get less power. And with hotter intake temps, you cannot run as much boost with the same margin of safety.
I did not try to quantify these things because there are a lot of variables involved, and I don't know what the right value for each of them is. Also, a lot of these things compete (like less flow due to backpressure versus increased pressure drop in the IC) and I don't know which ones "win". It is clear that hotter intake air has a cascade of negative effects, but what the resulting measurements of temp, flow, and pressure would be as an effect is hard to predict. Overall, I suspect that the effect of hotter intake air is much like the loss in power that the difference in the cooler and hotter compressor inlet temps suggest.
Hot air kills air pumps, too.
-Max
We haven't accounted for all the effects yet. So here is my stab at what happens when the intake temp increases:
If your intake air is 30F hotter, your intake charge will be 30F hotter coming out of the compressor. Because the air is hotter relative to the outside air flowing through the intercooler, the IC efficiency will nominally increase. Since the IC removes more heat, you might only get a 10F or 15F increase in intake temp as a result of 30F hotter intake air at the compressor inlet. I would be interested to hear of any measurements people have done of these temps, to check our assumptions. This is the issue that has already been raised, hopefully made a little more clear with my description.
One effect not yet accounted for is that the cost of increased efficiency in the IC is a slight increase in pressure drop. To make up for the increased pressure drop, the compressor has to compress the air a little more, which both makes the compressor outlet air even hotter and also increases the backpressure. The backpressure fights the incoming intake charge, making it a little hotter and a little less dense with oxygen when it finally gets into the combustion chamber. Backpressure also results in less flow through the engine, so you get less power. And with hotter intake temps, you cannot run as much boost with the same margin of safety.
I did not try to quantify these things because there are a lot of variables involved, and I don't know what the right value for each of them is. Also, a lot of these things compete (like less flow due to backpressure versus increased pressure drop in the IC) and I don't know which ones "win". It is clear that hotter intake air has a cascade of negative effects, but what the resulting measurements of temp, flow, and pressure would be as an effect is hard to predict. Overall, I suspect that the effect of hotter intake air is much like the loss in power that the difference in the cooler and hotter compressor inlet temps suggest.
Hot air kills air pumps, too.
-Max
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