speedtrip

I had my maxima dynoed again today to see if converting my CAI to hybrid improved performance with the VI. I have asked xHypex to host the dyno.

To my surprise the torque curves of the hybrid and CAI are very similiar. The hybrid torque curve is not as smooth as the CAI but the difference in torque values between the two are small. In the order of 1 to 2 ft. lbs of torque per a given RPM which is within the error of the dyno. The two torque curves are similiar until 5k rpm where the hybrid torque curve does not drop as quickly and holds the torque a little longer. There's no appreciable gain with the hybrid until 5.7k rpms where it jumps to a 9 ft. lbs increase.

Peak hp did increase with the hybrid dyno vs. the VI with the CAI. Max power is now 182.2 at 6.1k vs 176.1 at 6.1k with the CAI. Max torque pretty much stayed the same, 0.7 increase.

On paper it appears the hybrid intake is better suited to the VI but only after 5.7k rpms. On the road the hybrid intake feels like the stronger of the two as well. I feel that rpms climb much quicker with the hybrid intake vs. the CAI.

I am surprised that I did not see the low end loss with the hybrid which I anticipated. However I also thought that the hybrid intake would be stronger from 4.0k rpms on up.

MaximaRider

iTrader: (3)

i am drooling for a VI now to bad i am flat broke

iansw

iTrader: (7)

Speedtrip - NIIICE.
It's appreciated how you as well have spent quite alot of money for Dynos.....good job!

MaximaRider-
If you've got half now and half in a couple of months, I am running a deal.

See my thread in the GD Forums.

IanS

hakk97se

Damnit I want one too, however the $4000+ bill for school that will be arriving any day now will quash any hopes of that one in the short run. Need a damn y-pipe and suspension too. Guess I'll have to live with my PR CAI for a while. At least it sounds cool.

Sigh. You lucky guys!

speedtrip

Thanks!

I was pleased to see the increase in peak hp. Comparing my baseline dyno with the hybrid dyno it's hard to believe that they are the same car. I wish that I could get back the little bit of midrange I loss but that may just be the nature of the VI manifold.

Gumby510

Noob Question

With a CIA on a dyno, won't it be affected since you are NOT moving? Since that's where the benfit comes in with having cold air filter. Do dyno places have fans or something? Sorry for the questions if they seem silly. I have never been to a dyno shop in my life.

iansw

iTrader: (7)

Yep, most Dyno shops have big fans.

xHypex

iTrader: (1)

Once you are moving both intakes are getting considerably cooler air so it's sort of a moot point. I'd go for the extra top end
Here's the latest and greatest on the VI for everyone to look over. I have asked speedtrip to fill in spreadsheet data for his baseline run so we can do some more comparisons and I'll host that when he gets it back to me. Until then here's his dynoes (at the bottom of the page).
http://www.vanillaice.com/webmasters/hype/mrc/mevi.htm
-hype

JdawgX

Part of the reason that you're seeing bigger increases now is also due to your ECU learning the new air/fuel maps that it needs for the new VI. It takes the ECU a bit (250-500 miles) to learn that the VI is there and how to take advantage of it. Same thing as any after market MAF. The manufacturer always states that the ECU needs time to learn that the part is there.

Either way though, great numbers! I look forwayrd to getting the VI myself!

Nealoc187

iTrader: (23)

I disagree. I ran the same times and same trap speeds an HOUR after putting on my Y-pipe as I did exactly a week later.

I truely feel this is a total misconception that the ECU needs to "learn" at WOT. At part throttle, this may be true (though I'm not convinced it is), but at WOT your ECU uses pre-programmed fuel and timing maps, which NEVER EVER change. So regardless of any mods you do or don't do, peak power, as is shown on dyno runs, should not be affected by whether or not the ECU has adapted to the mods.

xHypex

iTrader: (1)

Agreed
-hype

Dave B

Sweeeeeet. The POP style intake is the key. If you look at the new HP curve, HP actually continues to climb to 6100rpms and then slowly plateaus. With the CAI, the HP curve went pretty much flat right at 5500rpms and held very steady till 6100. The POP should give a bit more upper RPM acceleration.

Ditto on the ECU thing. I don't think the ECU does any learning except when it's first started with the new mod. Once the car is run thru redline, it's relearned the new parameters. At WOT, there is no learning. The ECU is in closed loop mode (ie it will not learn).


Dave

iregula

nice writ eup!

jcy98maxse

iTrader: (8)

what is your hybrid setup?? did u use a pop charger w/ a pr upper tube or something different?? Also Cattman is selling that same setup for $165 or something like that, is that a good deal??

Nealoc187

iTrader: (23)

Anyone want to plug these new numbers into Cartest and give us revised shift points. I'm thinking (and hoping) redline, redline, redline with the hybrid intake dyno data.

MaximaRider

iTrader: (3)

Iansw- Thanks for the offer but i can't get myself into things i can't afford seeing as i have AGX struts/Spring Springs/& an SMC sts all waiting to be installed, VI later on this summer for sho!

speedtrip

I had a place racing cai. I removed the air filter and lower tube from the cai set-up. I am still using the upper tube that connects the throttle body to the MAF sensor. Then I took the air filter and stuck it on the plate that bolts to the MAF assmebly.

$165 sounds like a reasonable price for what you are getting. I paid more than that for my PR CAI.

Mishmosh

iTrader: (3)

So did you re-use the CAI air filter or did you need to get a cone filter with adapter plate? I was looking at conversion before but wasn't sure what I would need. Also, did you get a backbrace to hold the thing stably?

After the trouble of drilling that CAI hole in the fender well, I may just leave it but the Hybrid makes it easier to maintain the filter (ie. dusting it off) and getting some better top end.

Dave B

Redline, redline, and redline would be a given. Pretty much the VI power delivery rivals the 00-01 VQ. It would be nice to be able to take 1st to about 7000rpms (ideal), but I don't think I could justify buying a JWT ECU for that purpose. Sure, there are power gains with the ECU, but the gains are from 2500-4900rpms. With the VI on a 5 speed, you'll be out of the power gains of the JWT on each shift.


Dave

dwapenyi

iTrader: (3)

See? Told ya


DW

speedtrip

I just reused the CAI filter. It's a snug fit with that air filter so I just put down some cubes of self adhevise 1" thick foam insulation to keep the filter from vibrating. Those two 3/4" vacuum hoses connected to the upper CAI tube keep things in place.

dwapenyi

iTrader: (3)

I wonder what would happen if you then used the bigger POP filter from the JWT or Stillen, and added a venturi. You would then see the advantage, if any, of just those items over the CAI filter.

DW

JdawgX

Well, you are all more than welcome to go and call Granatelli and ask them. They're one of the largest manufacturers of MAFs and they'll be happy to let you know that an ECU in fact takes time to learn to take advantage of new mods.

Dave B

Are you serious? Granatelli makes REPROGRAMMED MAF sensors for mostly F-Bodies. All MAF sensors are similiar in function, but the Granatelli units are modified units. Plus, they don't make NEAR the power they advertize. The ONLY reason the Granatelli units perform slightly better than stock MAFs is because the programming is adjusted to compensate for breathing mods.



Dave

iansw

iTrader: (7)

Wow...you schooled him....heh

NmexMAX

iTrader: (22)

Knowledge is power.

JdawgX

Schooled? lol Ya.... okay. By not addressing the fact that the ECU still needs to learn that the MAF is changed, he clearly "schooled" me.

Keven97SE

I would have to say that I agree with JdawgX on this issue. An ECU does indeed take time to learn the optimal parameters for a modification.

There are two learning modes the ECU follows. One is short-term fuel trim, which occurs during on one trip. The ECU will temporarily (for that trip) modify the fuel trim table for that one trip. However, these changes are not permanently applied unless subsequent trips also show the same fuel trim requirements. This is called long-term fuel trim. It takes several trips at least for the ECU to modify its long-term fuel trim tables.

Although in WOT, the ECU does indeed follow a set fuel map, in WOT the ECU also looks at the long-term fuel trim table. This makes sense, in that it would be silly for the ECU to detect changes needed when running in closed-loop mode but ignore those requirements when in open-loop mode. If you had a failing MAF, for example, you could blow the motor due to a massively lean condition if no compensation were made due to detection while in closed-loop mode.

In summary, the ECU as applying what it's learned in closed-loop to its open-loop fuel maps. It takes a few trips at least to permanently save the changes.

The Maxima service manual states that the ECU does operate in this manner, although its pretty vague on the details (such as specifically how many trips of repetitive short-term fuel trim changes it takes before changes are applied to long-term trim, etc).

That all being said, I don't think it's generally a good idea to listen to anything someone has to say when their name contains "dawg".

Kehops

You make a good point but if you think about it, once the JWT ECU begins being less efective at around 4900RPM, the VI kicks in and ensures constant power up until redline. So you get increasing power from 2500RPM when the JWT takes effect up until 4900RPM and then from 5000RPM when the VI kicks in until 6500RPM. Sweet combo if you ask me.

speedtrip

That could be a possibility. I did drive my max for two days and went through a tank of gas (385 miles) before I went to the dyno. Plus the dyno place is 75 miles one way from where I live. So I had the mileage.

In the previous dyno thread I posted I switched from CAI to the hybrid intake the day after I dynoed with the CAI. Butt dyno noticed immediate results. I had a louder and longer tire chirp from 1st to 2nd and I actually noticed I was being slighty pushed back into my seat past 6k rpm which I did not feel before. The rpms climb much faster with the hybrid.

I believe that a hybrid or POP intake are better suited for the VI. As to what extent the ECU plays in this role is anybody's guess.

xHypex

iTrader: (1)

Ok well regardless on the ECU the Hybrid performed better than the CAI. I wonder how much a velocity stack would help the airflow rather than simply having a filter bolted to he MAF (since I believe the CAIs don't have velocity stacks). We're not talking about a lot of power, but every bit helps.

Here's the spreadsheet showing the Baseline versus VI (with CAI and Hybrid)

Also once Mr. Cranman has his rpm switch he is dynoing and he does have a JWT ECU. For those of us with 97+ cars we don't have an ECU anyway so that's not even an option.
-hype

JdawgX

Keven97SE

I wish I could post the dyno plot, but I plotted the dyno results in Excel.

I don't see any substantial trend for either torque plot. The CAI plot is more erratic and has more "holes" at higher rpms, but there is no general trend of less torque vs the hybrid. Both plots are essentially identical below 5500 rpm. The erraticness of the CAI plot above 5500 looks like it's due to something like knock retard, etc. At 6100 rpm both intake dyno the same torque. If the CAI was weaker you wouldn't see that.

Hate to break it to everyone, but the CAI and hybrid dynos don't indicate any substantial differences.

NiceGuyEddie

Live With???

Craig Mack

Can someone tell me why low end dyno's on hybrid/pop vs. CAI are NOT worthless??

I agree and believe that on the highway the short pathed POP out does the CAI. It's just commen knowledge there..

But, in the lower power band range the dyno seems completely worthless..the hood is opened, allowing all the engine heat to dessipate, and a huge fan is blowing. In the real world out on the streets, with a closed hood and no huge dyno fan blowing is obviously a totally different situation and temperatures are ALOT higher..

I guess there is no real way to tell how much more torque and HP the CAI gives over the pop down low since the dyno seems like a huge cheat. I'd like to see a type of dyno where both cars are physically ran on the streets with real life situations..I bet the power curves and certain ranges of power would be significantly different.

Dave B

The erratic behavior of the CAI plot is showing the CAI running out of breath. To me, and what's been said all along, the CAI isn't able to breath very well after 5500rpms therefore power goes flat. The POP in the otherhand continues to breath therefore it increases power and the power curve actually has a "hump" instead of a plateau. It doesn't matter if both intakes have the same amount of torque at 6100rpms, the POP is breathing better from 5500-6100rpms. That's very important.

I've dynoed my massively modded "Poorman's CAI" vs my HKS intake. My HKS intake made more power at ALL rpms especially after 5400rpms. The accusations that POP style intakes loose torque is a myth. However, there's no doubt the CAI has trouble breathing in the upper rpms.

Dave

Dave B

Craig-

Underhood temps do influence the way a POP style intake works ONLY at a stop or at a very slow roll. Once moving, the underhood air is significantly cooled especially if the POP is running the stock lower airbox and a heatshield. The POP intake charge will cool almost to the point of a CAI. Mod for mod, a POP equipped Maxima should always be quicker.

One thing you should remember is that once the intake manifold is heat soaked, it doesn't matter what the engine is breathing thru. The car's going to be a bit slower.


Dave

xHypex

iTrader: (1)

I don't see how the CAI versus Hybrid difference can't be seen It's not huge, but it is there

Also I believe this "hybrid" didn't even have a velocity stack which has the possibility to make slightly more power by smoothing the intake flow and reducing the initial turbulence.
-hype

Anachronism

It's funny, any time there is real data on the CAI vs Pop debate the Pop guys interpet it to mean a pop is better and the CAI guys think it means the CAI is better. Looking at the spreadsheet there is no more than a couple HP difference until 5600 RPM. My guess is that below 50 MPH or in the first 5-10 seconds of driving the CAI gives a significant temerature advantage (I will be testing this when my CAI finally gets here) that is probably worth a couple of horsepower. At the track this extra power is probably benificial but on the street I don't think I would get much use of a couple extra ponies over 5600 RPM. Of course we don't know how much difference there would be on a regular manifold and if a velocity stack would help, so the debate rages on.

I see xHypex posted a dyno chart that is much easier to interpet, still I come to the same conclusion. If you add a couple of HP to the CAI for the temperature advantage it would give more usable power for most street use.

dwapenyi

iTrader: (3)

I would tend to agree. There's something missing in Dyno measurements, or the measurement itself is flawed by its nature, that doesn't totally bring out the differences between CAI and POP. I converted my CAI to a hybrid. I do miss the low end torque that the CAI had. And the CAI was consistant, very linear. Now with the Hybrid, I feel more power from 5000-6000 rpm than my CAI could ever muster. On the street, where you spend mst of your time below 5000 rpm, the CAI is the better more livable intake. On the highway, though, the weaknesses of the POP/Hybrid do disappear, and you get a killer top end.

DW