5-spd VI dyno Episode II "Attack of the intakes"
05-17-2002, 12:40 PM
#41
Supporting Maxima.org Member
Join Date: Oct 2001
Posts: 1,431
Heh, aside from the VI, someone needs to invent a dual Hybrid/CAI setup.. Like the upper intake piece connects to a Y connector that switches with some sort of butterfly like the VI between a pop directly connected to it and a longer pipe leading to the CAI. Some of these "look I made my intake for $15 from plumbing parts of Home Depot" people need to get on this. Hahahaha. It could even switch at the same RPM as the VI is set to.
I agree with the previous poster tho. I have a PR CAI and on the street, it's great. Even on the freeway, I spend most of my time between 2 and 3500rpm. The CAI is great on the hills. There are many places where my car (auto) used to have to downshift when going over the mountains, where now with the CAI it doesn't have to. This has resulted in better gas millage for me. I do really long for the upper end power whenever I have to pass someone tho. Oh well.
I agree with the previous poster tho. I have a PR CAI and on the street, it's great. Even on the freeway, I spend most of my time between 2 and 3500rpm. The CAI is great on the hills. There are many places where my car (auto) used to have to downshift when going over the mountains, where now with the CAI it doesn't have to. This has resulted in better gas millage for me. I do really long for the upper end power whenever I have to pass someone tho. Oh well.
05-20-2002, 01:47 PM
#42
Re: 5-spd VI dyno Episode II "Attack of the intakes"
Originally posted by 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.
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.
-John
05-20-2002, 03:21 PM
#43
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Thread Starter
Join Date: Jan 2001
Location: Boise, ID
Posts: 500
Re: Re: 5-spd VI dyno Episode II "Attack of the intakes"
Originally posted by Mr Cranman
Hey speedtrip, I was looking over your numbers and It seems that the baseline dyno had a higer torque and almost higer HP. Which leads me to believer that maybe the VI is opening up around 4100 or 4400, robbing you of torque. You might want to just have someone rev up the car while someone watch the VI to see where it is actually opening compared to your RPMs. Because it seemed to just plateau at 4100-5100 if not drop a little. Just a suggestion. =)
-John
Hey speedtrip, I was looking over your numbers and It seems that the baseline dyno had a higer torque and almost higer HP. Which leads me to believer that maybe the VI is opening up around 4100 or 4400, robbing you of torque. You might want to just have someone rev up the car while someone watch the VI to see where it is actually opening compared to your RPMs. Because it seemed to just plateau at 4100-5100 if not drop a little. Just a suggestion. =)
-John
As to why there is a mid-range loss that's anyone's guess at this point. Personally when I look at all the dyno sheets it's clear that the VI has changed the torque curve through out the entire rpm range. Peak hp has moved from 5400 rpm to 6100 rpm and peak torque has moved from 4800 rpm to 3200 rpm. A mid-range loss just may be a characteristic of the VI manifold. Also note how low end was slightly increased and how the VI flattened the torque curve. I was really hoping that the hybrid intake would gain back the mid-range I loss.
We need more time to gather more information and to figure out the optimum set-up for the VI. Maybe a true POP intake, the stock air intake for a variabe intake manifold, or a less restrictive exhaust will not show the mid-range loss that I did. Or maybe it will.
I encourage the next batch of VI recipients to get a dyno done with the OE manifold. There are differences between the two manifolds.
05-20-2002, 03:26 PM
#44
Re: Re: Re: 5-spd VI dyno Episode II "Attack of the intakes"
Originally posted by speedtrip
Yes, the mid-range took one on the chin. The way the dyno is set-up I can watch the rpm screen on the computer and the variable intake actuator at the same time. The VI is opening at 5000 rpms. If you look closely at the CAI VI and hybrid VI dyno sheets you can see a small decrease at 5000 rpms. The decrease is more pronounced on the CAI VI dyno. This is the VI valves opening.
As to why there is a mid-range loss that's anyone's guess at this point. Personally when I look at all the dyno sheets it's clear that the VI has changed the torque curve through out the entire rpm range. Peak hp has moved from 5400 rpm to 6100 rpm and peak torque has moved from 4800 rpm to 3200 rpm. Also note how low end was slightly increased and how the VI flattened the torque curve. I was really hoping that the hybrid intake would gain back the mid-range I loss.
We need more time to gather more information and to figure out the optimum set-up for the VI. Maybe a true POP intake, the stock air intake for a variabe intake manifold, or a less restrictive exhaust will not show the mid-range loss that I did. Or maybe it will.
I encourage the next batch of VI recipients to get a dyno done with the OE manifold. There are differences between the two manifolds.
Yes, the mid-range took one on the chin. The way the dyno is set-up I can watch the rpm screen on the computer and the variable intake actuator at the same time. The VI is opening at 5000 rpms. If you look closely at the CAI VI and hybrid VI dyno sheets you can see a small decrease at 5000 rpms. The decrease is more pronounced on the CAI VI dyno. This is the VI valves opening.
As to why there is a mid-range loss that's anyone's guess at this point. Personally when I look at all the dyno sheets it's clear that the VI has changed the torque curve through out the entire rpm range. Peak hp has moved from 5400 rpm to 6100 rpm and peak torque has moved from 4800 rpm to 3200 rpm. Also note how low end was slightly increased and how the VI flattened the torque curve. I was really hoping that the hybrid intake would gain back the mid-range I loss.
We need more time to gather more information and to figure out the optimum set-up for the VI. Maybe a true POP intake, the stock air intake for a variabe intake manifold, or a less restrictive exhaust will not show the mid-range loss that I did. Or maybe it will.
I encourage the next batch of VI recipients to get a dyno done with the OE manifold. There are differences between the two manifolds.
-John
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