With all this talk about CAIs vs POP/hybrids, I decided to convert my intake back to my Poorman's CAI just to see if I could feel any differences. The Poorman's CAI consists of removing all resonators, use a midpipe, tapping a 2.5" shopvac hose into the stock intake snorkel and running the hose under the car to pull cooler air, and cutting a hole in the driver's side of the lower airbox to run another piece of shopvac hose behind the headlight. On the dyno (pre-VIM), my Poorman's CAI made the same exact power from 2000-5400rpms as my HKS intake. Only after peak power (5400rpms) was the HKS able to hold on to a little more power (+5 fwhp at 6200rpms). Now that I've got the VIM, my power really doesn't drop, even at redline.

The results of the Poorman's CAI are quite interesting. First off, the Poorman's CAI is very quiet and doesn't have the wail of the hybird. It's definately noiser than stock, but observers would be hard pressed to know you've got intake work. As for power, the car definately feels stronger off the line (idle to 2500rpms) in normal driving. Usually my car feels a little soft on initial take off, but that's all gone now. Everything feels more fluid and the motor feels smoother at all rpms. It's all very strange. At WOT, it is VERY easy to bang the rev limiter because the intake is so quiet and you don't hear much of the VIM switchover. Upon entering each gear on a shift at WOT, the motor feels much stronger I dare say it feels more "torquey". To add even more fuel to the fire, humidity has been damn near 100% due to unseasonably warm weather with on and off rain all day (ie power robbing conditions). What's even scarier is the intake is running a stock paper filter. At full on WOT in every gear, it's very hard for me to discern between the ultimate power of the hybrid vs the Poorman's CAI. Topend acceleration really feels the same I'm sad to report. With the stock manifold, I could tell a difference in topend, but not now. I'm very perplexed by all this. Maybe a CAI system somehow matches the flow characteristics the VIM? I don't know. I'm going to continue to experiment and I'll keep you guys posted. Weather is suppose to get cooler and much drier. I'll be going to the track next week and I'll be make runs with the different setups. We'll see how it goes.


Dave

 

maybe the VIM adds so much topend that the any difference between the two is no longer signifcant enough to notice

 

Dave,
You said "torquey"! Do all of your experiments on a cold, crisp day and then let us all know of your findings

 

Hmm...well if I have my information right, the MEVI gives you the DE-K top-end, but also like the DE-K, it comes at some expense of low-end power. I'm pretty sure I read it right that with the MEVI you do lose a good bit of low/mid-range power, correct?

That said, a CAI, which in theory operates best at the low/mid-range, would be a good mod for those with the MEVI. Since it operates best at the low/mid-range, the CAI would help give you the low-end that had with the stock manifold, all while just depending on the MEVI for the top end that you lacked with the stock manifold.

When I eventually get around to doing an intake on my car, it'll be either a hybrid or a POP. I have plenty of low-end, but definitely need some help at the top-end, and I don't plan on doing the MEVI.

On the otherhand, if I had a 00-01 DE-K (plenty of top-end), I'd probably hook up a CAI for an intake mod to help give it back some of the low-end that that engine is missing.

 

Dave, I'm gonna get flamed here but have you tried the stock intake? I'm curious if those resonators, especially the one in the mid pipe region, help with the breathing of the VI. I've read somewhere that everyone wants the low end back that the stock setup offers but wants the top end. So, with the stock setup you'd have the low end back and then with the VI you should get some more top end Guys don't flame - I don't think anyone is an intake specialist, there are so many variables.

 

Not to nit pick but was your dyno performed with the hood up. The comparison of a CAI vs Pop vs Hybrid(short ram) should be tested so that conditions match actual aspects of driving. If you drove with your hood open than that is how you should dyno, if you drive with it closed that is how you should dyno. The big debate is that when the filter is in the engine bay it gets air that is not as dense because it is hot. If you open the hood that takes that major part of the equation out. I will hopefully be sponsoring some dyno runs and will request that the hood be closed (I will warm the car up) and the large fan be put in front of the car (maybe even wait to turn it on until 2000rpm) while performing the runs. Thanks for the input, the VIM has always been a coveted mod for me.

 

I'm pretty much using the stock intake, all I've done is smooth out some of the kinks like removing the resonators and I've added an extra source of air into the factory airbox. A resonator does nothing to help in air flow, instead it is there to quiet the intake noise down. Same goes for resonators in exhaust sytems.

I see no problems with dynoing a POP/hybrid car with the hood up because at the track you let the car cool down with the hood up and end up racing with a cold engine bay where heat isn't an issue. Running a fan on the dyno does little give real world "blow thru" while the car is strapped to the dyno. Only a very small area of blowing air is directed at the car. You could dyno a car with hybrid with a cold engine and the hood closed and I'm certain the dyno numbers would be the same as with the hood up. I don't know if you've ever dynoed, but most shops want your engine cold on the runs to give accurate back to back results, so theroretically running with the hood closed is pretty meaningless. The reason shops like to dyno with the hood up is to help keep the engine cool (block, heads, manifold, radiator). Running on the dyno with the hybrid and a hot engine bay is a bit unfair because the fan is not blowing air into the engine bay like it would be on the street.


Dave

 

The 00-01 needs all the toruqe it can get. While is does produce more torque than the 95-99, the extra weight of the car really offsets it's extra power, especially in the lower gears. I drove Russ's 01 5 speed (stock) last year with Russ and Bryan H in the car and they both openly admitted my car felt worlds stronger at all speeds. At the time, I had an intake, y-pipe, B-pipe. Russ and I raced a couple times on the highway from 50-100mph I walked him pretty good. Russ's 01 eventually ran 14.8s@93mph (stock) which might be the quickest stock 00-01 to date.

You're crazy to pass up on the MEVI


Dave

 

I understand what you're saying Dave but to change the tone/pitch of the incomming air, the resonator affects the air flow. I think it would be similar to blowing over a jug top. You creat a little air ripple of sorts that produces the sound - this is getting beyond the scope of my text so I'm gonna quit talking about it haha. I hope to get my VI soon and will be playing around w/ intakes once I install it. I'm curious to see your results. Not that it matters but I'm currently running a Stillen w/ the $15 rubber coupling midpipe and have gotten my best times w/ that setup - no dynos though.

 

THis is what you need http://www.charm.net/~mchaney/homedyno/homedyno.htm. Or you can bust out the old stopwatch and time the acceleration in 3rd gear from 2000-6500rpm or 5000-6500rpm. Make sure you do at least 3 runs and average the results. Once you get the results I can aproximate how much power is being lost/gained during the pull.

 

It's like taking the top off a pot that has just begun to boil, it will stop because you have just released a lot of heat. Same with the engine bay. Letting your engine cool is fine, but I would think that giving your intake such an abundant source of fresh air (your hood is the size of the engine bay, thats opening up a huge supply of fresh air) would be a disadvantge when comparing. Your filter sits near the hood, and since the hood is open this is where your air would come from. I have looked at the engine bay trying to find a place in front of the car that I could run an intake, however a source of fresh air is not possible unless you remove the lights because of the radiator. So I think that you really won't get too much flow to your filter from outside air (underneath perhaps, but it is still a long way across a hot block to your filter), I wish I had the link but someone tested the temp inside the engine bay and it didn't change from a stand still to 35mph (for some reason they didn't go faster than this because of the streets they were on, but thats still 1st gear and at least most of second.)
Back to the boiling pot, open up the top just a little and run around with it or blow a huge fan at it (this represents your engine bay with the hood closed, while moving in your car), I promise that the moving wind across the pot and the small opening at the top will not cool it as quickly as standing still and just taking the top off (representing your hood open on the dyno standing still.)

I'm not trying to disagree with you, just for my application I would want the hood closed and engine warm since I race like this.

Again this is not a flame I am just trying to learn different perspectives, my questions are-

Where in the engine bay does cool air flow to cool the engine, I know the radiator but that still blows like 200 degrees, and do you think the cooling and source of air is caparable to having the hood open?

Could you clear up Hybrid intakes for me, and why they are not called short rams other than the fact that the pipe length on short rams is researched and developed?

 

On the street, the hybrid/POP is probably sucking in hotter air than a CAI or stock intake. BUT at the track, where it counts for most of us, you're running with a cold engine and a cold engine bay therefore heated air is not a factor. Sucking in hot air is definately not a good thing, but it's not 200 degrees underhood. I took measurements at various speeds and the hottest temp I ever recored (on a 80 degree day) was ~150 degrees. That reading was at a stand still. Once I got going around 35mph, the temp dropped to ~95 degrees. That extra 15 degrees over ambient is not that significant, IMO. I've always felt the honest way to test the hybrid/POP vs CAI is to run the CAI piping OUTSIDE of the car. This will allow both intakes sucking ambient fresh air.

The "hybrid" POP intake means that there is a midpipe installed in place of the big resonator between the throttle body and MAF. That's all.


Dave