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Discussion Starter · #1 ·
Well guys, I searched. And searched. And searched some more but I was unable to find anything on the subject. I've been noticing lately that none of the other auto owners seem to want to make power w/in their powerband. So I've done some "tests" and the auto shiftlanding points are as follows. 1st-2nd 4,300-4,400 rpms, 2nd-3rd 4,800-5,000rpms. I really didn't have a chance to get into 4th gear as I was doing close to 90 in 3rd gear and I was on a highway and had to slow down. This really doesn't matter as most racing will be done in the first 3 gears, at least in an auto. So the ideal powerband in an automatic b18b would be from 4,300-6,800 rpms, for drag racing anyway. That's a pretty wide powerband of 2,500 rpms. I just wanted to point all this out just in case anyone was interested. I would also like to hear some opinions of a feasible setup to achieve this powerband in a b18b. Even 4,500-7,000 would be great for an LS/GS/RS/SE. Anyone have any ideas?
 

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Did you run the car to redline during your runs?
 

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Well that was interesting to know.
MrMoe's Dyno

I received a torque increase from 4000 to 5200. After that the torque started to die off
 

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Great experiment, I was actually going to do the exact same thing today.

4.5k to 7k:
Intake wise

That's from MD's post about intakes. Looking at that the short ram would be a good choice? cause I mean we want to get as much air as possible when the shift lands. and the short look like it's winning in that chart, width not being a factor there though.
Leaving all the middle stuff stock for now, moving on to exhaust, I'm the advance exhaust tech II article by md, looks like a custom, 2.25 straight through would benifit us the most because of the flow velocity of or engines. It's good for 200 whp, which is a lot considering we got like 105 or so to the wheels, but with mods it would go up. So possibly the ITR exhaust would be good for lesser modded ones, yet it bottlenecks down to 1.9" in some spots according to the article.

The setup I think would be best for our autos, this is my opinion, cost wise, (if I ever get the money, I'll do it), is to run a short ram intake, with the 2.25" straight through, while spraying nitrous right after the shift and right before the next one. But if nitrous isn't what you want, maybe a cam upgrade and other goodies might be what you are looking for.
The ultimate would be a turbo that would spool up at around 4k to red. Like say a T3 turbo, that would be an ideal one for a feasible set up. The problem with that is the torque converter other wear that comes up, but you know about that.
You could supercharge, but I don't really know what that does to a powerband, I think it shifts it down, but I don't have real experiance.

If anyone else could contribute, it would sure help us auto guys.
 

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I had to go back and read this again.

MichaelDelaney on Nov/30/02 said:
a powerband is the longest rpm range that has the highest torque.



So here we have ITR cams vs. Skunk2 Stage 2 cams in a properly fuel tuned engine.

only look at the torque curve. Ignore the hp curve.

The ITR cams have a "midrange" powerband and the Skunk2's have an upper rpm powerband.

The ITR torque is at the peak level or near the peak level from 5700 rpm (stock ITR VTEC switchover) to 7000 rpm. That's it's powerband. It runs for 1300 rpm in width. The powerband here is narrowed due to the higher CR used in this particular 1.8L B18C engine.

the Skunk's torque curve is near or at peak torque from 6300-7800 rpm. It has a higher powerband location and width. When we say "higher powerband location" we don't mean the torque value is higher. We mean the peak torque for that engine begins at a higher rpm and it's range is at a higher rpm.

Here is Erick Aguilar's record all motor 2.1 L B18C1. The powerband is from 6500 to 9500 rpm on the torque curve. Notice how nice and flat it is and how wide it is. 3000 rpm in width! that is amazing.



Most of us are happy with a 2000 rpm powerband width which is the average.

You can determine or shift the powerband up or down the rpm range (for your given redline) by choosing the correct combination of parts with certain dimensions and by tuning (eg. cam gears, valve lash, ECU reprogram).

Some parts are designed (dimensions and layout) for an upper rpm powerband (6300-> redline) and others are designed for midrange (3500-6000 rpm).

Don't even think that you can mix and match midrange powerband parts with upper rpm parts to get an ultimate wide powerband. They just cancel each other out and you get LESS power and a narrow powerband. Some novices just do this unwittingly because they don't understand the effect of design on powerbands...and end up buying parts that cancel each other's gains.

it's not a stupid question. Some advanced people don't even get this.
So my powerband is from 4800 to 5800. Not much to work with but I'll take it.
 

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Discussion Starter · #7 ·
A supercharger will shift the entire powerband all the way across the rpm range up, not down HP. MrMoe, damn you for the sideways dyno chart,
j/k. I am interested in an all motor setup. Nitrous was also a feasible option. My current setup is dc 4-2-1 2 piece, 2.25" high flow cat, 2.25 ITR catback w/bottlenecks removed, to a Greddy Evo style straight through muffler, and an ebay short ram. So I'm guessing that the crower 403's would make power in this area, or another comparable cam. It's nice to see other auto owners interested in doing something w/their "slushbox."
 

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Yeah, i think hakamoto is trying to say and me too, that we are trying to make the power band that long. 4.5k to 7k. If not make it that long, at least add some area under that curve. But since the auto tranny shifts at redline, that's what we got to work with.
 

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Hakamoto on Feb/16/04 said:
A supercharger will shift the entire powerband all the way across the rpm range up, not down HP.
hp beats him up for saying that, it's connect to a belt and starts spooling when the accelerater is pushed. You have to excuse me haha.
 

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Well, as far as wear and tear is concerned, I just started looking into rebuild kits. My main concern with the torque converter is the low stall speed. . .

With intakes, I have already made my choice. I wanted the best of both words, short and cold air. That is why I went and got a hybrid. All I need now is a better flowing air filter.
 

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Discussion Starter · #11 ·
I also read that thread today Mr. Moe. This is what got me thinking about it, so these tests were conducted on my way to work. Also, thanks for doing a baseline run for us auto guys, I'm a little depressed seeing those numbers but I'd like to see what an auto is really capable of, be it FI or NA.
 

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Discussion Starter · #12 ·
Well so far it seems that the ideal NA setup for an auto b18b, who is interested in drag racing, or at least a powerband from 4,300-6,800 would be a 15-21.5" intake, or of the name brands the comptech icebox would do well, a nice hybrid tri-y 4-2-1, and a full 2.25 exhaust sytem. I haven't seen any auto dyno's with a mild cam like the 403's.
 

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Hakamoto on Feb/16/04 said:
So I've done some "tests" and the auto shiftlanding points are as follows. 1st-2nd 4,300-4,400 rpms, 2nd-3rd 4,800-5,000rpms.So the ideal powerband in an automatic b18b would be from 4,300-6,800 rpms, for drag racing anyway. That's a pretty wide powerband of 2,500 rpms.
That seems kind of funny. . . .

Quote: 1st-2nd 4,300-4,400 rpms, 2nd-3rd 4,800-5,000rpms.So the ideal powerband in an automatic b18b would be from 4,300-6,800 rpms, for drag racing anyway.
If these are correct, redlining is 2nd gear appears to be a waste of time. The tranny shifts you out of the powerband. It would probably be better off letting off the gas a little sooner so that the tranny shifts into 3rd within the powerband.
 

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Hakamoto on Feb/16/04 said:
Well so far it seems that the ideal NA setup for an auto b18b, who is interested in drag racing, or at least a powerband from 4,300-6,800 would be a 15-21.5" intake, or of the name brands the comptech icebox would do well, a nice hybrid tri-y 4-2-1, and a full 2.25 exhaust sytem. I haven't seen any auto dyno's with a mild cam like the 403's.
This is a prime example of what I like to call a lack of resources.(not money) With the cam profile given by the 403, upgrade to the transmission are a must. Even if it is just for tunning purposes.

However (this is the lack of resources part) because there are not the many places that offer upgrades to the automatic transmission . . .and the fact that they are so fragile, not to mention all the stereotypes and myths, many people are afraid to put money into it.
 

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Discussion Starter · #15 ·
I'm only getting into motor modifications as most people will never drop that amount of money in modifying their auto trannies. And why does that seem funny MrMoe? And I would like to know what you meant by lack of resources? Also the shift from 6,800-5,000 is actually keeping you closer to the powerband it has stock, but you could drop the revs a little to be back at in your powerband.
 

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MrMoe on Feb/16/04 said:
However (this is the lack of resources part) because there are not the many places that offer upgrades to the automatic transmission . . .and the fact that they are so fragile, not to mention all the stereotypes and myths, many people are afraid to put money into it.
Basically this. . .
If we were to compare the number of aftermarket companies that sold torque converter to clutches, it would be a short list.

Meaning that there are not a lot of people willing to break the stereotype that automatic imports can not put up decent numbers. (not yet anyway)
 

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Look at my dyno.
(try not to hurt your neck too much)


After 5800, the torque dies off. Having the tranny shift anywhere after 5500 is actually a decrease in torque.
 

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Hakamoto on Feb/16/04 said:
Yes Mr.Moe, but that's a stock dyno correct? I am not stock and would imagine w/my mods that peak torque has been shifted a little higher into the powerband. I would love to make a dyno run but it seems that the cheapest dyno in my area is around $275/hour.
Does that include engine tunning?
 
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