Nismo87SE

Over the last week or so I've been trying different combinations of tubing from the MAF to filter in the fender well. During testing I've used my techtom to get peak MAF voltage/coolant temp readings, and road dyno for comparing torque/hp curves. For the dyno tests I did 3 pulls 2 in 2nd gear and 1 in 3rd gear since the speed limit is 65mph and I don't need tickets . All of the road dyno runs are SAE corrected for weather conditions, otherwise the results could skewed. Unfortuatley I didn't get pics of all the setups I tried, however the setups I tested were a 2.5in, 3in, 2.5in-3in hybrid piping also I'm still using the OEM tubing from the MAF to TB. As of now all of my power mods are PS header, 2.25in cat/B-pipe, JWT s3's/ECU (cam program), outlaw phenos, UR udp. Here is the test results in excel format 3rd gear CAI test, 2nd gear test.

I'll start with the 2.5in CAI, out of all the setups this one sounded the best to me. It gave the engine a very nice throaty sound from 5000-6000rpm and 7000-7500rpm. The throttle response seemed slightly quicker than before but it could've been from a miscalibrated butt dyno. After a few WOT runs I felt the engine seem to labor more after 6600rpm than before. No matter what gear was used the MAF only registered 4.55-4.57v @ 7500rpm. The engine seemed to pull smoothly from 4000-6000rpm, however once I used road dyno there was a loss in torque from 3500-4500rpm of an average 2.6wtq/2.1whp with a max of 4tq/3hp around 3800-4000rpm. This setup also hit power peak about 200rpm earlier than the other setups and seemed to offer less power from 6500-7000rpm. Overall this style didn't make much power and it actually lost some in spots but it did sound the best if that matters.

The next setup was a full 3in piping from MAF to filter, since funds were limited I used dryer tubing . The first thing I noticed was the engine sounded different, the throaty roar of the 2.5in was gone as if the engine changed to a higher pitch. Throttle response may have been better than with the 2.5in CAI but I can't confirm it lol butt dyno = broken. According the MAF however it wasn't flowing any more air than the 2.5in piping did. I only got 4.55-4.57v @ 7500rpm again as I did with the 2.5in. It seems that there is a difference in power delivery between 2nd and 3rd gear. During the 3rd gear pull the engine didn't seem like it wanted to pull up top. So there was a noticable fall off up top the dyno run confirmed it, there was an average 5hp loss from 6900-7500rpm. 2nd gear had a different result 3in had 1-2hp average gain over the others at the same rpm . Overall I like this setup better than 2.5in.

My baseline before going with 2.5in and 3in was with my hybrid (ghetto) setup which is below.


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What it's is a 2.5in piping (tailpipe repair flex tubing lol cheap and used in 2.5in test) that grows into 3in where it meets the couplers. Actually the ID of the couplers is like 3.25in so I cut the lip where the clamp goes off one elbow and put it around the 2.5in pipe so the OD would match the ID of the coupler and it work perfectly as seen with extra tape. The sound didn't change much if at all from the 3in and throttle response at first didn't seem as quick. But this setup does pull better up top, actually alot better. I registered 4.65-4.68v from the MAF and it pulled hard all the way to my shift light (7400rpm). On the dyno it made more power than the 3in over 6900rpm and almost matched it everywhere else in 3rd gear. For 2nd gear the 3in had 1hp average advantage from 4600-7300rpm but the hybrid had the best average midrange (4000-6000rpm). Basically hybrid is better in 3rd gear, 3in is better in 2nd gear and since a the last 1/8 mile of a 1/4 mile race is all 3rd gear (for me at least) hybrid is better setup. Not to mention is topend pull is better, the engine revs so much quicker up top. Overall I like this hybrid the best, I wanted to try a 4in piping but my battery is too wide to allow it later on I plan on getting that genesis 11lb battery and then i could give the 4in a try.

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91 Nissan Sentra SE-R: KYB AGX's, eibachs, prothane mounts, ES suspension bushings, addco RSB, FSTB/RSTB, CAI, JWT C2/ECU, 3in B-pipe, UR UDP, nitrous
Best ET: 13.57 @ 99mph

 

green96ser

Nice write up, what kinda filter are you using?

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02 G20 Sport 5MT

Nismo87SE

I'm using a generic 3in cone filter.

totaled200ser

i don't think you will see any gains with a 4in, and when you are dealing with #'s so minimal, there are many things that may contribute besides diameter, big is not neccessarily good, as you proved

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DnS Performance
Imported Auto Center, INC
96 g20 auto, stock

Storm88000

I have the AEM CAI which I believe is 2.5" unlike the more popular Hotshot or Place which is 3.0" - I think the AEM sounds better and helps more.

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Jordan - '94 Sentra LE
'07 Honda Fit Sport
www.myspace.com/jordanwhite

Froz3n00

i have 200sx se-r hotshot CAI... 3 inch... and it is definently NOT high pitch... it sounds deep and mean... maybe low port is different

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1996 200SX SE-R

HotShot CAI.::.HotShot Header.::.Stromung CatBack.::.Prokit (><) .::. 16" Rota Grids
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SHIFT_gears??

Sr20kidD

setup between a 3 in and full. 2.5 the aem is dies up on top..
i noticed this with my butt dyno.. also the it revs a bit slower w/more torque at low rpm..

witha 3 inch HS. i felt it revved much faster and not as torqie but smoother through out.....


hence the 2.5 from tb to maf and 3 inch from maf to filter..

sounds great.. and i dont feel any loss up top. and feel torque down below...

this is the setup i have..on my 94 and i feel its far more bitchin than the full aem i have on my 91..

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The classic feels left out cause of the attention the Evo is getting.
Although, I talk to it and let her know that she is still my number 1

honkeybizkit

i think that the material used also plays a part in performance.. dryer tubing is definately not my choice of Mat'l for a CAI. granted it may be 3", but the inside is not smooth, and how does the resonance in a 3" Al or steel tubing compare to that of flexible plastic or thin aluminum?

otherwise goos ideas on how to test these different setups out.

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Jonathan Schultz

1992 Sentra SE-R
1997 200SX SE-R SOLD! **Now Replaced
2001 Lexus IS300

Froz3n00

^^^

good pt about the material, im sure you're right about the resonance, totally different materials

Monsoon

I had the Place Racing CAI on my '92 Sentra SE-R, and that car fell flat on it's face in the higher RPM's. All I had done to it was 17 degrees timing and the CAI, but the car lacked any high end power at all. It had a huge surge in the mid range (up to about 7000 and then it died). I think your information sounds about right (although it doesn't explain why that intake gained that car 13lbs/ft of torque, yet only 5hp ).

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Galaxy Gray Metallic 2006 Honda Civic Si (with no-torque mod).

Nismo87SE

I would've liked to use metal however I don't have access to it or a mandrel pipe bender. I guess I could order some 3in mandrel bends and go from there but that is pretty expensive. The dryer tubing is very flexable and easy to install/remove not to mention cheap :p. In case anyone is wondering how much power the car made with each setup below are the figures.

1. 2.5in CAI made 138whp @ 6300rpm, 123wtq @ 4600rpm
2. 3in CAI made 139whp @ 6300rpm, 127wtq @ 5200rpm
3. 2.5-3in CAI made 139whp @ 6300rpm, 127wtq @ 5200rpm

Something interesting happened too engines love cooler temps. During the baseline hybrid tests the conditions were 40*F, 86%, 30.16in-hg, 50ft ASL. Not correcting for conditions the car made 148whp/136wtq which would be a nice number to throw around but it would make the test invalid . I'm sure I could get more power from a better header and an open cutout.

99SE-L

I felt 2.5" piping feels much better down low and in the mid range over the 3" PR cai.

btw where did you get the road dyno and how much does it cost?

tlSeR20DE

kinna off the topic, but how is that road dyno working for you? sounds interesting.. where did u get it from and how much? that site didn't have a price or anything on it..

Nismo87SE

http://www.charm.net/~mchaney/roaddyno/
Road dyno has been an invalueable tool for me. To me it seems to be very accurate as long as you input the actual weight and weather conditions. It costs $150 and I believe its worth the price, I've tested my car and the families not to mention a friends 99 prelude with nitrous too.

Scarpa

I'm pretty sure that varying the length of the piping will also yield changes in power output, due to resonance. You may want to add that as a variable to your experiment.

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Paul
'92 NX2000 w/ mods

Toolapcfan

^^^^^^^^^^^^^^^^^^^^
What he said.

I thought the HS CAI made the most gains of any aftermarket CAI offered? If so, I'd just copy that, I'm pretty sure it's 2.5" from TB to MAF and 3" from MAF to filter, and as long as your bends and lengths are similar, you should have the same results in the end for a lot less $$$. Or if the AEM is better copy that. If I was going to stay NA, I'd buy the best dyno proven off the shelf CAI, measure it and send it back. I'm surprised more people don't make their own headers using a similar method. Although I suppose fabbing the plate that mounts to the head would be the hard part, since it'd need to be fairly think and would take somewhat expensive cutting heads and a vertical mill, or a decent drill press to make. Not to mention, if header piping is a lot thicker than exhaust piping, getting madrel bends that thick would be tough to find and possibly costly.

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- Rob

Wicked White '08 EVO GSR "Jaws"

Nismo87SE

That could be a possiblitly, the 2.5in cai tube is the same one used for the hybrid. The 3in intake was about the same length as the hybrid was however the 2.5in one was about 2-3in shorter than both.

Subculture

It may sound better, but the Place Racing/HotShot CAIs make more HP.

Storm88000

I dunno, although I have no hard proof my car seems to feel better with the AEM, and I had a Hotshot about a month before I switched.

Sabre 200 Gxi

Ho lucky are you guys that they sell CAI kits in the States!!

I'm from SA and Nissan accesories are few and far between.

Anyways, I'm going to manufacture my own CAI. Need som e help though. Can I leave the standard piping between the TB and MAF?

Will it be better to:

Remove the filter box, replace it with a Cone and heat shield and then have a cold air pipe that runs through to a vent in the bumper?

or,

Have a cold air pipe straight from the MAF to a cone filter located behind the bumper/grill?

Any assistance appreciated!

ps: Who can help me to have my cars pic hosted so I can reveal it to the world? I think you guys will like the SA version SR20 pulsar...