why short ram greater loss than cai?

[kenis138]

Why do short ram intakes cause a greater loss in low end torque than CAIs do?

[sniperSI]

Why does everyone think you get a loss of low end torque with an intake?



Check the dyno sheets, you don't lose torque with either, you get more.

Cold Air SI
http://www.injen.com/webpages/testing/dyno_graphs_1104/original/RD1575.jpg

Short Ram S

http://www.injen.com/webpages/testing/original_files/is1475.jpg

[Peking]

Originally posted by sniperSI
Why does everyone think you get a loss of low end torque with an intake?

Yeah, I find it silly that alot of folks think that (usually noobs, not saying that is the case here). I find it sad how so many believe what others say without doing some research first.

[mrfixit687]

you lose torque in part throttle conditions, ie daily driving, the dyno sheets only show full throttle

[BluePearl03Si]

I thought it was exhaust headers that had low range torque loss?

Oh well, show's what I know.

[rs_1101]

it always depends on the setup. usually large tubing slows air intake and reduces fuel oxidization on the intake.

the same goes for the exhaust, but in reverse. large tubing means higher exhaust backpressure, cuz of slower moving exhaust.

[mrfixit687]

Originally posted by rs_1101
it always depends on the setup. usually large tubing slows air intake and reduces fuel oxidization on the intake.

the same goes for the exhaust, but in reverse. large tubing means higher exhaust backpressure, cuz of slower moving exhaust.

no larger tubing on the exhaust means theres less backpressure

[Dunrick]

cai's will not lose noticable power at half throttle, but having an exhaust will. Kenis I think you got the right setup for what you want. Intake, header & stock exhaust with hondata should be the best usable torque for daily driving...

[Vertigo]

Another reason might be, because the inlet temp of the ambiant air is hotter for the sri than the cai. You gain 1% of HP for every 11 degrees reduced the air temp is.

[BluePearl03Si]

N/X makes that intercooler cooler thingy that releases CO2 to supercool the intercooler on turbo apps.

I wonder if there would be a way to apply that to a Normally Aspirated car.....

[Vertigo]

It would be just like a nitrous setup. Insted of nitrous, fill the bottle with CO2.

[Lynx]

Originally posted by rs_1101
the same goes for the exhaust, but in reverse. large tubing means higher exhaust backpressure, cuz of slower moving exhaust. [/B]

If this where true, cars would have a 1/4 exhuast. In theory it would move faster at the end but the pressure at the engine would be tremendous. Try pumping 200 gallons of water a minute thru a garden hose, the bottleneck would be the hose causing pressure build up at begining of the hose.
Larger tubing moves exhaust slower but in larger volumes and with less pressure at the engine.

[silver]

piping diameter controls the velocity of the exhaust gases. imagine having two straws, a normal diameter and one, say the diameter of your mouth. when you blow into the normal one you have a steady stream of air moving and evacuating from your mouth. when you blow into the big one the you'll be unable to create the constant blow because the air basically shoots all over. the ease in blowing is actually related to back pressure. when you lower the velocity you increase the back pressure as was said earlier. but really the point behind it is to have the perfect sized piping to optimize the velocity so that you can create a vacuum effect behind the closed exhaust valve. and plus the back pressure is not going to be affected enough through the piping to make much of a differece, that's where the muffler plays a part.

and yeah i don't see where the idea of losing tq on the sri started?

[Lynx]

Correct me if I'm wrong, but when people upgrade to a bigger carb, Turbo or Super Charger they also upgrade to bigger diameter exhaust. I wouldnt think that this is to increase there back pressure. Volocity is one thing but volume is another. You want your engine to breathe and have a small amount of back pressure for the scavenging effect Which is why engines have valve overlap. Example: Boosted engine need less back pressure becuase they do not rely on the scavenging effect so much to pull in the next intake pulse. Thats fine, you breathe in and out of a straw and see how blue you get. I'll breathe out of my mouth, thank you.

[02SilverSiHB]

Originally posted by sniperSI
Why does everyone think you get a loss of low end torque with an intake?



Check the dyno sheets, you don't lose torque with either, you get more.

Cold Air SI
http://www.injen.com/webpages/testing/dyno_graphs_1104/original/RD1575.jpg

Short Ram S

http://www.injen.com/webpages/testing/original_files/is1475.jpg
LOL, that is a good comparison man, that's a type s with an exhaust and the injen sri and a si with just the cai...come on :rolleyes:

Anyway, the short ram from what I've seen and felt gives better gains up top than below, maybe because of the less bends and it rushes the air in quicker? but the heat soak kills the sri after a while.

With the cai the more bends give it some initial torque imo. I had both the sri and cai on the new si and felt my torque come back at the lower rpms with the cai over the sri

[02SilverSiHB]

Originally posted by kenis138
Why do short ram intakes cause a greater loss in low end torque than CAIs do?
hey, kenis, is it just me, or did no one read your question? :D it looks like everyone that posted is going on about torque being lost with an intake....you asked why does the sri have less torque than the cai...correct?

[Peking]

Originally posted by 02SilverSiHB
hey, kenis, is it just me, or did no one read your question? :D it looks like everyone that posted is going on about torque being lost with an intake....you asked why does the sri have less torque than the cai...correct?

Woops, just noticed that. Dammit, I like to pride myself on reading sh*t right :D

[rs_1101]

Originally posted by Lynx
If this where true, cars would have a 1/4 exhuast. In theory it would move faster at the end but the pressure at the engine would be tremendous. Try pumping 200 gallons of water a minute thru a garden hose, the bottleneck would be the hose causing pressure build up at begining of the hose.
Larger tubing moves exhaust slower but in larger volumes and with less pressure at the engine.

im not that dumb man. i kno. i was oversimplifying i admit. but it is the reason that our car comes with a 1.25inch b pipe section, to gain torque at 4500 rpm which is where most drivers are likely to shift. upgrading to a 2.25 increases torque and hp peak to a higher flow rate. in exhaust tuning, there is a balance between flow capacity and ideal flow rpm, being that you get more peak flow at lower rpms as the pipe gets smaller. if you have a 3-4" pipe on your intake or exhaust, your car never reaches that peak flow rate, and youve actaully lost some power.

[silver]

Originally posted by Lynx
Correct me if I'm wrong, but when people upgrade to a bigger carb, Turbo or Super Charger they also upgrade to bigger diameter exhaust. I wouldnt think that this is to increase there back pressure. Volocity is one thing but volume is another. You want your engine to breathe and have a small amount of back pressure for the scavenging effect Which is why engines have valve overlap. Example: Boosted engine need less back pressure becuase they do not rely on the scavenging effect so much to pull in the next intake pulse. Thats fine, you breathe in and out of a straw and see how blue you get. I'll breathe out of my mouth, thank you.

we're not talking about fi, that is different. for fi you can't really have too big of an exhaust. it is a completely different setup which really doesn't prove anything. it's like comparing the effects of a cai on a na motor vs a turbo motor. but this is getting off topic.

as for less tq then a cai, harmonic resonance and denser air.

[kenis138]

Originally posted by 02SilverSiHB
hey, kenis, is it just me, or did no one read your question? :D it looks like everyone that posted is going on about torque being lost with an intake....you asked why does the sri have less torque than the cai...correct?

Jeezus, leave a thread for a few days and see what happens!?
Yeah..lol..thanks 02 :D ;)

[Lynx]

Originally posted by rs_1101
im not that dumb man. i kno. i was oversimplifying i admit. but it is the reason that our car comes with a 1.25inch b pipe section, to gain torque at 4500 rpm which is where most drivers are likely to shift. upgrading to a 2.25 increases torque and hp peak to a higher flow rate. in exhaust tuning, there is a balance between flow capacity and ideal flow rpm, being that you get more peak flow at lower rpms as the pipe gets smaller. if you have a 3-4" pipe on your intake or exhaust, your car never reaches that peak flow rate, and youve actaully lost some power.

I wasnt saying you where dumb. I just wanted a better explanation (which you have just given). I'm old school, v8 and such. different way of thinking back then.