s1mpsons

iTrader: (5)

Well, not exactly. Im more interested in the numbers, not just "a little stronger" and "beat the everliving ****." That description was a little vague. I'd really be interest in a graphical comparison, but i think that would be asking for too much.

Isnt the range from 3500-4000 rpm questionable, in terms of boosted power on nonseq and seq?

Mahjik

iTrader: (1)

Yes, that area is "questionable" area. The non-seq system will provide a little more power around thr 4000 rpm range. If the car is making 10-11 PSI around then, that's BOTH turbos making that power rather than 1 turbo.

However, with the sequential system, you'll have full boost of at least a single turbo well below 3000.

The overall power really isn't effected all that much, just "where" the power is on the curve. While the rotary does like the upper RPM band (as if you can't make a lot of torque, to make power you need higher rpms), IMO, that doesn't mean you get rid of what little bit you have down low.

FD3RotorTurbo

iTrader: (1)

wow this was forever ago when i made this thread...

but put into consideration what port you have as well. with a stock port you will spool the turbos faster as with a street port or a race port it will take longer to spool them up.

rynberg

My dyno plot from when I was near stock is no longer on the forum, but here's a plot of 911GT2s mildy modded non-seq car at 12 psi.



On my near stock plot at only 10 psi, I made 200 ft-lbs of torque from 2800 rpm until the transition near 4500 rpm. You'll notice that 911GT2 is only making 150 ft-lbs of torque at 3000 rpm and doesn't hit 200 ft-lbs until 4500 rpm.

How's that for a descriptive illustration of how much low-end you lose with non-seq on a mildly-modded setup?

s1mpsons

iTrader: (5)

Mildly modded eh? 260wHP when mazda claim 255 at the crank! Ok, well anyone have a mildly modded (or bone stock) dyno run to put side by side with this nonseq dyno run?

TwinTurbo93

Wow, look at that air fuel ration how steady it is.
Btw, what was that break up between 5.5-6K rpm? All 3 lines have it at the same time. I abviously don't know much about dyno charts, just a dumb question I guess.

rynberg

The point was that my less modded car running 10 psi of boost still had 50 ft-lbs more torque at 3000 rpm than a non-seq car running 12 psi tuned by Steve Kan. 911GT2's car here didn't equal my torque output at 3000 rpm until 4000 rpm, even with the 2 psi advantage and more mods.

You wanted a reasonable comparison between a seq and non-seq in a stock to mildly modded cars. I gave it to you. If you don't like the answer, that's not my fault...

rx_obsessed

Very interesting comments in here. I don't have a 7 yet..I'm looking. I've seen some nice cars with NS conversion...so I'm trying to read up. It's interesting hearing the different takes on powerbands. I think I'm coming from a different place....the two cars I have at home right now are a 2000 Civic SiR (SiR is a Canadian name...160 hp vtec..the coupe, not the new one) and a 2002 Acura RSX Type S...200 hp six speed....both revving MONSTERS. I'm used to almost no torque especially in the Civic....111 pounds...vtec comes on at 5500 and rev-limits at 8700...which i hit as often as I want (Honda's don't break!!). So, for me personally, I don't think I'd be phased by non-seq, I think I'll prefer it. My years with these high-revving Hondas has made me a much better driver and a precise shifter, I think. I've had no choice but to have perfect gear selection if I expect to beat people with bigger engines. If I fall out of my powerband in those Hondas, I'm dead. So I do just that....I don't fall out of my powerband. As I look around, I won't INSIST on non-seq, but I really think I'd be fine in it. Oh...just so you don't think I'm jumping from 160-200 hp into a 7....I also have a Dodge in the low 13s so I have handled some power....I just was almost afraid to say Dodge in here lol....hey I love to be open-minded and love all different cars!!!!

s1mpsons

iTrader: (5)

I just wanted to see both graphs

rynberg

Ok, I found my old dyno plot on my computer -- RB catback and downpipe at 10 psi on otherwise stock sequential car:

rx_obsessed

Ok but let's discuss race situations. Sequential and non obviously have their different strong points. The graphs are great, but I say....which car gets through the traps first?? Different powerbands will affect what speed you'll actually reach in the quarter as well as shift points....shift points can be huge....if you're stuck at the end picking between labouring in the wrong gear or falling out of your power to make a last second shift, it's tough....maybe one set up leaves you at the line with a bad shift strategically. Which car wins the race??? I know I've beat cars with more horsepower and lost to cars with less because of other variables. And in addition to straight line racing....which setup leaves you in the best situation for going into and coming out of corners?? I think those are the real questions. Maybe pushing the power higher in revs is smart to reduce wheel spin. Nothing kills a time more than not moving.

speedracer2235

Why does this question get asked so often? Just hit search on non-seq. There are plenty of threads about it already with the same damn arguements. Just drive/ride with someone who already has it. Look in their engine box and see what the difference is. It's very noticeable.

s1mpsons

iTrader: (5)

Im gonna graph them both on excel by hand and solve for the areas underneath the curves. See which one really has a better all out power and torque band. You are gonna have to wait a couple of days because Ive been cramming lately for my exams/midterms

KevinK2

area under the curves depends on initial rpm selection, and really means nothing in the end, since you don't know the time required to develop the hp or tq points, assuming exact same dyno was used.

po'man vs seq:

1)dynos and butt knows seq will do better in roll on single gear with a 2.5-3k start. if then drag racing continues thru the gears, seq would stay ahead since seq is then also locked in twin mode.

2)if both dn shift to 4-4.5 k at slow initial speed, transition will likely hurt seq, po-man's ns wins.

3)if both dn shift to 5K at slow initial speed, both are locked in twin mode, ... tie.

4)drag race from stop, only 1st gear will make a diff, and depends a bit on who wants to trash his car more ... winner not obvious.

dynos for full ns vs po man's ns, all else same, would be helpful as it shows diff in output of seq in twin mode (same as po' man), vs full ns.

rynberg

You need to learn how the twin-turbo setup really works. If you did, you would not have posted that. As I and many other people have said REPEATEDLY -- in a hard driving situation, there is zero difference between the two setups (other than a very slight high end advantage for TRUE non-seq due to removal of air flow restrictions). In a seq car, once the transition is hit, the car is in non-seq mode until you drop below 3k rpm. In a road racing situation, after the 1st shift from a dead stop out of the hot pits, you are in non-seq the entire time. Same for drag racing. Where seq DOES have an advantage, is in auto-x and normal street driving. Where non-seq has the advantage is a more reliable and consistent setup.

rynberg

It won't work. His dyno is at 12 psi, mine's at 10 psi. He's making significantly more power once both of his turbos are finally at full boost.....unless you want to compare area beneath the curve from 2k-4k rpm...haha

`sl!mXP

I have non-seq. setup but have mixed feelings about it. Id kinda rather have the sequential turbos because until 4k rpms I have absolutely nothing, which actually hurts a lot off the line. Id rather have the sequential now that Ive started drifting and autocrossing because you really spend a lot more time in the lower revs than in the redline area, but for straight line racing I can see where you might like non-seq. The non-sequential is better for top end power and reliability (or so Im told...) but the sequential I feel would help me a lot more on the track for autox and drift.


Id rather have a little more power down low than a little more up top, but thats just me, youll have another couple guys tell you they like the extra power up top. Its hard to decide until you do the conversion, keep in mind what you want the car to do. Do you want to be a track fanatic or do you want to be a highway cruiser? Now that Ive started drifting and autoxing I like it a lot more than killing hondas on the highway - its just more exciting

jpandes

That's exactly how I feel. I like how NS always works and pulls hard to redline but I hate the lack of low-end power.

jpandes

Rynberg's dyno plot is very telling indeed. Take a look at my dyno sheet with the Po' man's NS and my car isn't stock.

By 3000 rpms the a stock FD with Seq. turbos has a whopping 70 more ft/lbs of torque than I do! I don't hit 200 ft/lbs until 4200. THAT SUCKS! I may just have to convert back to seq...

s1mpsons

iTrader: (5)

I can really see it now. The only real benefit of NonSeq is like the 1000 rpm before the the 2nd seq kicks in for seq cars.

MazdaSpeed93

Right now i have sequential and was wondering what you have to get in order to make it non-sequential. I'm fairly new to the rotary world, i have had my car since Sept. 04

kosoku

Supra TT has has similiar mod called 'TTC(true twin conversion)' or something. people do that mod when they have problem with sequential setup.

I tried it and I absolutely hated the lag. I can't believe nearly half of people at supraforums likes non-sequential. Why give up the low-end torque when you can have it?

rx_obsessed

Ok well that's cool. I don't even have an RX7 yet so learning is exactly what I'm doing. I will say this though....Everyone seems to hate high-revving, extra shifting and everyone loves the torque....that's all good...whatever blows your hair back right? But I'm coming from a different angle, having driven vtec Hondas the last few years. Basically every car had more torque then me. I would LOVE to see the temporary smiles on people's faces..everyone would beat me off a launch and they'd think they had won the race. Those Honda engines don't even wake up unil 5500 rpm...the other guy's engine would be falling on it's *** and the high-revving machine would take over (well of course I could lose too.....who doesn't?? ). It was something I really got to enjoy. So, maybe for me, I don't care about losing the low-end. To me, the low end even in NS will feel strong compared to a Honda approach. And maybe I'm wrong again here....you guys are saying that in sequential setup, you're getting full boost by like 1800 rpm? How isn't that producing more wheel spin than having your power come on at around 3200 with a proper NS setup? And I would only get one properly done,...I'm looking at one right now with NS with proper mods, done professionally. ...I'm not arguing with anyone..you guys HAVE these cars lol....and know about them...I really just need to learn about the two setups cause I am shopping for my 7! Obviously I just need to drive both.......

rx_obsessed

Actually never mind that...I don't even need to drive them. Looking at the graph, I know I'll like NS better...it works violent toward redline!..That's what I love. That's how I've been driving. The sequential peaks at 4500 and just tapers down to redline?? That wouldn't feel right to me...I'm just talking personal preference here, not which one is better.

rynberg

THEY ARE BOTH EXACTLY THE SAME AFTER 4500 RPM. I think it's very poor logic to make up your mind on something when you haven't even driven it, especially when you still don't understand how it works.

After 4500 rpm, both turbos are fully online in either setup, there is zero difference in power output or character. On true full non-sequential cars, you will pick up a FEW ponies at the high end due to removing airflow restrictions. With seq, you make full boost by 2800 rpm or and essentially hold that until just before 4500 rpm, when there's typically a slight dip in the torque curve and then a small rise before slowly tapering off. With seq, you will make more power from 0 to at least 3500 rpm (usually closer to 4k rpm). With non-seq, you will make more power from 3800-4000 rpm to 4500 rpm. After 4500 rpm, both setups will make exactly the same power (with the few hp exception noted above).

Now you tell me which setup makes more sense for street driving? Like I said earlier and have said many times. In hard driving except for auto-x, the car is essentially running non-seq, no matter whether the car is seq or non-seq. So, I see ZERO reason to convert to non-sequential other than boost reliablity concerns.