I just simply refuse to believe Infiniti desginers figured something out that noboby else did..
Almost every other car I've owned, has had a beneficial intake upgrade..
Look at the mustang and camaro dynos.. over 10+ rwhp with intake mods..
LS400 same way
So basically, you're telling me The Q45 has the most amazing intake system ever designed for a car? Bleh, I simply refuse to believe that..
Give it sometime, someone here will figure something out..
Even if it gives just a measely 5 rwhp, and a better sound, then it's still MORE BENEFICIAL then the stock system..
Sorry you will never convince me the stock system is the most optimal intake system possible for the Q. It's good, but it's not that good.
Latenight mod to the Q....
NOTHING, I repeat NOTHING comes optimal from the factory
There is ALWAYS ALWAYS ALWAYS compromises from factory equipment. Rather it's the ECU/drifeshaft/braking/intake/shifting.. everything is perserved for non performance, granny driving..
Just because Stillen/JWT was lazy, and didn't put the thought/effort into designing a nice cold air intake system, doesn't mean nobody here will..
I could always be wrong, but 99.999999% of the time, factory equipment is never the optimal way to go for performance..
I owned one of the most over engineered cars in history
Toyota Supra Twin Turbo... Basically a 450 hp car from off the showroom floor, with such slight adjustments, even I could do them.. the point is.. even in a car like that a 50,000 sports car.. Just about every part was still not optimized to full potential
I could be wrong, but I doubt it.. We have some talented people here working towards a solution, and I bet they will slap all the nay saying haters down hard..
My bet is on the talented nico folknot the haters
There is ALWAYS ALWAYS ALWAYS compromises from factory equipment. Rather it's the ECU/drifeshaft/braking/intake/shifting.. everything is perserved for non performance, granny driving..
Just because Stillen/JWT was lazy, and didn't put the thought/effort into designing a nice cold air intake system, doesn't mean nobody here will..
I could always be wrong, but 99.999999% of the time, factory equipment is never the optimal way to go for performance..
I owned one of the most over engineered cars in history
Toyota Supra Twin Turbo... Basically a 450 hp car from off the showroom floor, with such slight adjustments, even I could do them.. the point is.. even in a car like that a 50,000 sports car.. Just about every part was still not optimized to full potential
I could be wrong, but I doubt it.. We have some talented people here working towards a solution, and I bet they will slap all the nay saying haters down hard..
My bet is on the talented nico folknot the haters
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Q45tech
- Moderator
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
I've stated that there is 5.5-6"* water column of restriction MEASURED [at 6,500 rpm] after the stock filter to the outside air pressure.Drilled and tapped a metal tube in the center top of oem air box to which a rubber hose was connected to the manometer inside car..........at such low pressures/vacuums hose diameter or length doesn't matter much.
That way the pressures/vacuums can be tested on the road.The 5.5-6.0" applies in 1st gear, BUT in second gear at 90 mph the vacuum drops [to 4.8-5.3"] as the horn pressure builds and resonates. Based on pressure curves I'll bet at 135 mph the vacuum would drop even more [something like [down to 3"]
*5.5/27=0.204 psi................. 6.0/27=0.240 psi after filter
Lets have more scientific rigor to our test.
That way the pressures/vacuums can be tested on the road.The 5.5-6.0" applies in 1st gear, BUT in second gear at 90 mph the vacuum drops [to 4.8-5.3"] as the horn pressure builds and resonates. Based on pressure curves I'll bet at 135 mph the vacuum would drop even more [something like [down to 3"]
*5.5/27=0.204 psi................. 6.0/27=0.240 psi after filter
Lets have more scientific rigor to our test.
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szh
- Posts: 15932
- Joined: Tue Jul 23, 2002 12:54 pm
- Car: 2018 Tesla Model 3.
Unfortunately, no longer a Nissan or Infiniti, but continuing here at NICO! - Location: San Jose, CA
elwesso wrote:For the layman, what kind of restriction does this translate into.. I dont know what 5.5in water colum means...
About 0.2 psi. Normal air pressure is 14.7 psi ... give or take a few tenths. You can get this change of 0.2 just by going up a little bit in altitude, or on a rainy day.
Z
EDIT: I just noticed that Dennis quantified it too.
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AZhitman
- Administrator
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- Location: Surprise, Arizona
- Contact:
Keep in mind that the factory has to satisfy SO many interests.
Has to be QUIET, maintenance-able, unobtrusive, QUIET, unable to ingest road debris/bugs/water, QUIET, and did I mention QUIET?
They did a remarkable job satisfying ALL interests. I'll see what I can come up with, as I'm ordering a G-Tech Competition Pro (the rest of you guys need to step up as well) so i can quantify some of these efforts.
Has to be QUIET, maintenance-able, unobtrusive, QUIET, unable to ingest road debris/bugs/water, QUIET, and did I mention QUIET?
They did a remarkable job satisfying ALL interests. I'll see what I can come up with, as I'm ordering a G-Tech Competition Pro (the rest of you guys need to step up as well) so i can quantify some of these efforts.
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AZhitman
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- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Dennis - I'm not familiar with gauges and instrumentation, but is there a gauge i could use to measure the airbox pressure at speed?
Honestly, I think the BIGGEST difference created by this mod is straightening the convoluted path created by the OEM system, and allowing a SLIGHT (miniscule) pressurization of the airbox.
I suspect in certain conditions, the stock setup could actually REVERSE and create a neutral pressure condition or even a miniscule vacuum condition.
Honestly, I think the BIGGEST difference created by this mod is straightening the convoluted path created by the OEM system, and allowing a SLIGHT (miniscule) pressurization of the airbox.
I suspect in certain conditions, the stock setup could actually REVERSE and create a neutral pressure condition or even a miniscule vacuum condition.
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nuQ
- Posts: 1659
- Joined: Thu Jan 23, 2003 1:39 pm
- Car: 2003 Infiniti M45
2009 Dodge Caliber SXT - Location: Bethlehem PA
greg, az94Q, is there any measuring diff. between the reg. g-tech and the comp. pro???? i'd spend the $50 now for the basic model if they measure 0-60, 1/4 mile times, stopping dist. basically the same. this would be a great idea for us Q owners to buy these so we can do a measurable before-mod vs. after mod differences.
From GTechs site..
"There are several significant improvements over the original G-TECH/Pro Performance Meter that have been implemented in the new COMPETITION model. First of all, there are 3 accelerometers and they are fully temperature compensated. This in itself is a huge improvement in accuracy. Secondly there is a very sophisticated new calibration algorithm that allows much higher precision. Also the system now has 32 times higher resolution which speaks for itself. New Noise-Correction algorithms have improved overall accuracy as well. With all of these valuable features we are very proud to announce that the accuracy is now within 5/100 second. With the consistency at 5/1000 of a second! Absolute Horsepower and Torque measurements are within 3% and consistency within .5%!"
The functionality is the same, but the accuracy is supposedly better (according to gtech)
"There are several significant improvements over the original G-TECH/Pro Performance Meter that have been implemented in the new COMPETITION model. First of all, there are 3 accelerometers and they are fully temperature compensated. This in itself is a huge improvement in accuracy. Secondly there is a very sophisticated new calibration algorithm that allows much higher precision. Also the system now has 32 times higher resolution which speaks for itself. New Noise-Correction algorithms have improved overall accuracy as well. With all of these valuable features we are very proud to announce that the accuracy is now within 5/100 second. With the consistency at 5/1000 of a second! Absolute Horsepower and Torque measurements are within 3% and consistency within .5%!"
The functionality is the same, but the accuracy is supposedly better (according to gtech)
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AZhitman
- Administrator
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- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Ryan - My mods:
4.08 rear diffpolished TBB&M transmission coolerhomebrew ramair/cai255/50ZR16's16" 99 Q alloys20mm RSBBRM FSTBTokico BluesEibachspolyurethane bushingsSilverstars (fog, lo & hi)ATE blue brake fluidSS brake linesMobil 1 throughout
So mechanically, bone stock except for intake/rear diff.
JWT ECU is on the way, as are 18x8.5 lightweight alloys and drilled/slotted F/R rotors (and of course exhaust/headers).
4.08 rear diffpolished TBB&M transmission coolerhomebrew ramair/cai255/50ZR16's16" 99 Q alloys20mm RSBBRM FSTBTokico BluesEibachspolyurethane bushingsSilverstars (fog, lo & hi)ATE blue brake fluidSS brake linesMobil 1 throughout
So mechanically, bone stock except for intake/rear diff.
JWT ECU is on the way, as are 18x8.5 lightweight alloys and drilled/slotted F/R rotors (and of course exhaust/headers).
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HeavyDuty
- Posts: 1281
- Joined: Tue Sep 23, 2003 4:51 pm
- Car: 1995 Infiniti Q45
95 Nissan 240SX S14
96 Nissan D21
06 Nissan 350Z Z33
I did a similar mod to my 91 SE-R, back in...uh...ahem...91.
A 93 Lincoln Mark VIII air horn fits perfectly in the DS bumper opening, followed by a length of flex hose routed to the stock airbox. No one can tell me it didn't make a difference. If I plugged the air horn with my hand, the car shut off. Nicely sealed. The car ran 15.5 @89.7 just with that intake mod & HS headers, IIRC.
Greg, you could make a simple low-buck manometer with a board, & 10 feet of vinyl tubing. Mount the tubing to the board in a U shape & fill it with water on both sides, say 1/2 way up the U, positioned vertically. Connect the loose end to a drilled/tapped fitting in the airbox (like Q45Tech posted).
Go for a ride, let someone log where the water rises to, vacuum or pressure. I could post the exact diameter of the tubing, required length of line for the U, etc. in order to get some dumb country boy data for your airbox mod.
Stock airboxes have to be a compromise, as you posted, Greg. I believe the location of the air horn on the Q is positioned for pressurized, but non-turbulent air.
If anyone does this mod, be prepared for a slight surging at certain speeds. But, I ran one for 8 years & had no issues with the MAF or any other sensors.
A 93 Lincoln Mark VIII air horn fits perfectly in the DS bumper opening, followed by a length of flex hose routed to the stock airbox. No one can tell me it didn't make a difference. If I plugged the air horn with my hand, the car shut off. Nicely sealed. The car ran 15.5 @89.7 just with that intake mod & HS headers, IIRC.
Greg, you could make a simple low-buck manometer with a board, & 10 feet of vinyl tubing. Mount the tubing to the board in a U shape & fill it with water on both sides, say 1/2 way up the U, positioned vertically. Connect the loose end to a drilled/tapped fitting in the airbox (like Q45Tech posted).
Go for a ride, let someone log where the water rises to, vacuum or pressure. I could post the exact diameter of the tubing, required length of line for the U, etc. in order to get some dumb country boy data for your airbox mod.
Stock airboxes have to be a compromise, as you posted, Greg. I believe the location of the air horn on the Q is positioned for pressurized, but non-turbulent air.
If anyone does this mod, be prepared for a slight surging at certain speeds. But, I ran one for 8 years & had no issues with the MAF or any other sensors.
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Q45tech
- Moderator
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- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
THE MANOMETER MEASURES VACUUM OR PRESSURE.
Most industral facilities have air filters and they are used to measure the pressure drop [vacuum] across these giant expensive filters to determine change out time.
Manometers come in 2 types a slanted glass tube and the gauge type. The gauge types vary in full scale from 0.5", 3", 10", 15", 20" 25" 30".....and higher. You can find electronic manometers.
The trick is deciding what you need to measure and at what resolution [AND WHAT IS THE POSSIBLE OVERLOAD-----].
The vacuum in an engine is highest in the plenum*. Most are familiar with cheapo vacuum gauges which can read 0 to 30" of HG....[29.92" HG= 14.7 psi= 410 inches of water].
* Well it's highest in the cylinder but we have no way of measuring there......the closes universal port is the line that feed the fuel pressure regulator or the brake booster. Easiest to tee the regulator hose and measure there.......good enough to control fuel good enough to use as a measurement point.]
Manometers are 10 to 500 times more sensitive, allowing fine resolutions. As the drop across a filter might be only 1" of water and the WOT plenum vacuum should be less than 30" of water vs 275-300" of water when the throttle is closed.
I have 10 manometers [most from Ebay] they range from 3", 5", 10", 20", 30" and some super heavy duty models [strong enough to handle closed throttle vacuum] and still allow a 0.5" accuracy in measuring my 17-18" vacuum at WOT on a 30" full scale.
This 17-18" is the highest vacuum [system loss [restriction] from the air horn to plenum and only occurs at above 6500 rpm [where the system restriction is highest.
What we are doing is kind of like what supercharger engineers do. They look to optimize the plenum pressure -- WE are minimizing the plenum vacuum AGAINST the Atmosperic pressure!If 14.7 psi is atmospere then we are delivering 14.7 minus 0.6428571 = 14.057143 psi to plenum [with a 18" WC drop]
By definition the torque peak rpm is the point where each gulp [filling of each cylinder] is maximized.........max air flow per rpm......max volumetric efficiency. Above the torque peak rpm system losses start restricting the flow [per rpm].
When the slope of the rpm [vs 5252] and the falling efficiency cross is where we get the term :Horsepower .
When you measure at 4,000 rpm, you see very very low losses because all the restrictions were designed at that point [ok guys how much torque can we squeeze out of 4.5 liters].
If we have 0.6 psi worse case [at redline] then at 4,000 rpm you will see maybe 0.2 psi [5.6 inches of water] in the plenum at WOT.
Why nothing you do in front of plenum will affect below 4,000 rpm, there isn't any restriction to fix.
Pretty much the same with exhaust after the cats [at least on Q with its efficient dual exhaust]..............all gaind occur after the torque peak rpm.
Not to say that you can't find SOME --- just not as easy.You can remove the built in safety for fuel mistakes and the timing advance safety for summer and poor maintenance.
Most industral facilities have air filters and they are used to measure the pressure drop [vacuum] across these giant expensive filters to determine change out time.
Manometers come in 2 types a slanted glass tube and the gauge type. The gauge types vary in full scale from 0.5", 3", 10", 15", 20" 25" 30".....and higher. You can find electronic manometers.
The trick is deciding what you need to measure and at what resolution [AND WHAT IS THE POSSIBLE OVERLOAD-----].
The vacuum in an engine is highest in the plenum*. Most are familiar with cheapo vacuum gauges which can read 0 to 30" of HG....[29.92" HG= 14.7 psi= 410 inches of water].
* Well it's highest in the cylinder but we have no way of measuring there......the closes universal port is the line that feed the fuel pressure regulator or the brake booster. Easiest to tee the regulator hose and measure there.......good enough to control fuel good enough to use as a measurement point.]
Manometers are 10 to 500 times more sensitive, allowing fine resolutions. As the drop across a filter might be only 1" of water and the WOT plenum vacuum should be less than 30" of water vs 275-300" of water when the throttle is closed.
I have 10 manometers [most from Ebay] they range from 3", 5", 10", 20", 30" and some super heavy duty models [strong enough to handle closed throttle vacuum] and still allow a 0.5" accuracy in measuring my 17-18" vacuum at WOT on a 30" full scale.
This 17-18" is the highest vacuum [system loss [restriction] from the air horn to plenum and only occurs at above 6500 rpm [where the system restriction is highest.
What we are doing is kind of like what supercharger engineers do. They look to optimize the plenum pressure -- WE are minimizing the plenum vacuum AGAINST the Atmosperic pressure!If 14.7 psi is atmospere then we are delivering 14.7 minus 0.6428571 = 14.057143 psi to plenum [with a 18" WC drop]
By definition the torque peak rpm is the point where each gulp [filling of each cylinder] is maximized.........max air flow per rpm......max volumetric efficiency. Above the torque peak rpm system losses start restricting the flow [per rpm].
When the slope of the rpm [vs 5252] and the falling efficiency cross is where we get the term :Horsepower .
When you measure at 4,000 rpm, you see very very low losses because all the restrictions were designed at that point [ok guys how much torque can we squeeze out of 4.5 liters].
If we have 0.6 psi worse case [at redline] then at 4,000 rpm you will see maybe 0.2 psi [5.6 inches of water] in the plenum at WOT.
Why nothing you do in front of plenum will affect below 4,000 rpm, there isn't any restriction to fix.
Pretty much the same with exhaust after the cats [at least on Q with its efficient dual exhaust]..............all gaind occur after the torque peak rpm.
Not to say that you can't find SOME --- just not as easy.You can remove the built in safety for fuel mistakes and the timing advance safety for summer and poor maintenance.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
"K&N says that the conical shape opening on the front of a filter decreases the amount of air the filter can intake. They say the reason is that the intake tries to pull all of the air through the front of the filter. The air coming through the front of the filter causes sort of an equilibrium and will not suck air from the first 3/4 of the filter. That leaves only the front and the rear 1/4 of the filter sucking air. After that it all comes down to filter area. The area of the filter that actually sucks air without the open front is larger than the area that would be used if it had an open front. That is why K&N sold this type of filter for only a couple months and currently has nothing like it in their extensive line of filters. They strongly recommend not using a filter that has an open front."
Found this somewhere haven't really thought it through??????
Posted for what it might be worth
Found this somewhere haven't really thought it through??????
Posted for what it might be worth
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
http://www.knfilters.com/testmethod.htm ... esting.htm
After all a PERFECT 274 cubic inch engine can only accept 317 CFM at 4,000 rpm, 370 CFM at 6,000 rpm* and maybe 383 CFM* at 6,900 rpm.
* based on plenum vacuum [18" WC] it usually is 6-10% LESS and falls faster than the rpms gain above the HP peak rpm....otherwise the HP would keep going up with rpm
"The velocity pressure in inches of water is the raw number used to calculate CFM. Dywer Instruments makes a slide rule to convert the velocity pressure number to velocity in feet per minute. One other number we need to perform the calculation is the inside area of the flow duct where the pitot tubes are. If the tube were exactly 3” inside diameter, that equals 7.0686 square inches or .04909 square feet. If we had a velocity of 5000 feet per minute and multiply it by .04909 we have 245.45 CFM. "http://victorylibrary.com/mopar/bench.htm
http://www.installuniversity.c...0.htm
http://www.pro-flow.com/tech%20info/how ... l-flow.htm
Another interesting approach is to calculate by how much the air temperature rises by being squeezed thru the restrictions at 5,000 feet per minute...........about 12 F which would decrease it's density by ~~1% plus what ever temperature rise occurs from heat conduction into the system.http://www.stealth316.com/2-adiabat1.htm
After all a PERFECT 274 cubic inch engine can only accept 317 CFM at 4,000 rpm, 370 CFM at 6,000 rpm* and maybe 383 CFM* at 6,900 rpm.
* based on plenum vacuum [18" WC] it usually is 6-10% LESS and falls faster than the rpms gain above the HP peak rpm....otherwise the HP would keep going up with rpm
"The velocity pressure in inches of water is the raw number used to calculate CFM. Dywer Instruments makes a slide rule to convert the velocity pressure number to velocity in feet per minute. One other number we need to perform the calculation is the inside area of the flow duct where the pitot tubes are. If the tube were exactly 3” inside diameter, that equals 7.0686 square inches or .04909 square feet. If we had a velocity of 5000 feet per minute and multiply it by .04909 we have 245.45 CFM. "http://victorylibrary.com/mopar/bench.htm
http://www.installuniversity.c...0.htm
http://www.pro-flow.com/tech%20info/how ... l-flow.htm
Another interesting approach is to calculate by how much the air temperature rises by being squeezed thru the restrictions at 5,000 feet per minute...........about 12 F which would decrease it's density by ~~1% plus what ever temperature rise occurs from heat conduction into the system.http://www.stealth316.com/2-adiabat1.htm
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Jeff Williams
- Posts: 3394
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- Car: 1994 Infiniti Q45t
2000 Infiniti I30t
2004 Infiniti M45
71, 72, 73, 82 & 2000 Corvettes - Contact:
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Q45tech
- Moderator
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- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
"The strongest point: Minimizing the plenum vacuum against the atmospheric pressure."
Which is the same as maximizing the atmospheric pressure in the plenum. As that is all that fills the cylinders.
A manometer is just a precise barometer that uses the atmosphere as a reference...........but it is self calibrating for different altitudes and pressures.
As we are reading HOW MUCH below local instantaneous conditions.
I surprised that there are not magazine articles everywhere about using these as a cheap tuning tool for engines.Maybe because the makers of high flow aftermarket things don't want you to be able to check their cliams?
See they use CFM at 1.5" of pressure drop hoping you don't understand that the CFM in a NA engine has a finite wall based on displacement and rpm.
What good is having something that can flow twice [3-4x] what the demand will ever be.
Even the manometer is only displaying the average as flow is a sine wave similar to the shape of the came lobe with 4 peaks per engine rpm.
6900rpm x4= 27,600/60=460 pulses [flows thru system] per second..........every 2.1739 miliseconds but each flow is up to 2.75 times in width [intake cam duration] [but flow is starts slow until mid lift and stops slow] so we see a pretty flat line when all cylinders are added together.
Which is the same as maximizing the atmospheric pressure in the plenum. As that is all that fills the cylinders.
A manometer is just a precise barometer that uses the atmosphere as a reference...........but it is self calibrating for different altitudes and pressures.
As we are reading HOW MUCH below local instantaneous conditions.
I surprised that there are not magazine articles everywhere about using these as a cheap tuning tool for engines.Maybe because the makers of high flow aftermarket things don't want you to be able to check their cliams?
See they use CFM at 1.5" of pressure drop hoping you don't understand that the CFM in a NA engine has a finite wall based on displacement and rpm.
What good is having something that can flow twice [3-4x] what the demand will ever be.
Even the manometer is only displaying the average as flow is a sine wave similar to the shape of the came lobe with 4 peaks per engine rpm.
6900rpm x4= 27,600/60=460 pulses [flows thru system] per second..........every 2.1739 miliseconds but each flow is up to 2.75 times in width [intake cam duration] [but flow is starts slow until mid lift and stops slow] so we see a pretty flat line when all cylinders are added together.
AZhitman wrote:Planning on buying the G-Tech this coming week if i can scratch up some cash.
Anyone wanna jump in on one and share ownership? I can get it for $229.
I have a buddy of mine that has the Passport G Timer GT2.
http://www.escortradar.com/gtimer.htm
How good is that one compared to the G-Tech? I did it once to my Q. One try with a bad takeoff and 800lbs of people in the car, I managed a 0-60 of 8.3 sec. I didn't get my 1/4 mile. I had to slow down. I know that to get accurate readings, you need the weight, and drag coefficient of your car. I know that the Q's curb weight is about 4000lbs, but I'm not sure of the drag. I think it's about .31.