Also there might be some arguement that non seq is better for the shaft of the secondary turbo but I dont know about the motor. I've never believed that it did anything much for the motor and never heard a very convincing debate that made me thing otherwise.

If you know how it helps the motor I'd like to hear it explained.

I will agree that its less troublesome though, thats really the only reason I tell people to do it but you can also make the seq system trouble free, its just alot of work.

STEPHEN

 

The initial maxpesce point was too general. For a wot run thru transition, the power after transition at same boost is similar, as shown by data at brian's site.

Holding 5k at speed then going wot is another story. For seq'l, u are still in single mode, and there is a transition to go thru to twin mode, and gently bring power up. Above 5500 rpm, seq switces to non, so try your test at 5700 rpm ... should be no diff, seq vs the 'simple' ns.

again, not against non-seq, just against mis-representation of seq'l.

 

So nothing was different at all other than seq to NS on the strip.

But for a fair comparison maybe something SHOULD have been different. Driving NS a seq. both the same will probably work better with one mode. In Rikki's case perhaps the NS was better for his driving/launching style.

Just a thought

 

I running Non-seq and for me it works just fine, that i believe i will be keeping it that way for as long as i keep the car. Sure it may have some lag i learned to live with it ; and I do downshift to get to the power curve fro acceleration. Just like in any other regular car with an all motor kind. Also I think more of reliability,more mileage and less stress on the engine. If some guys like to go and have the most power, Hey thats their perrogative and their opinion and i respect that, We can do with our cars whatever we want, it`s the American way.
Wheter you like non-seq or not , you are entitle to your opinion. The way I see it is that if so much discussion and so many miles of tread can be writen to prove one way or the other is good or bad then they must be so close to accomplish the same goals that their small differences are driven by small factors. Small factors can allways be change to meet our individual needs.

Just one point i havent heard mention on any thread or disscusion on non-seq Vs seq that i would like to mention; maybe to clear some things up; is another reason why Mazda made our cars sequentialy turbocharged. lmagine 10 years ago, if you fell in Mazda`s demografical area of potential buyers of $30,000 sports cars (remember Mazda is in the bussiness of selling cars) You were probably 25- 35 years old making good money and well educated. That brings me to my point of if you were in the market for a super sports car and you were test driving an Rx-7 or even a Supra you were most likely to not be worrying about modifiyng your new car or taking it to the track not even constantly reving it`s engine around it`s red line. You wanted to buy a dependable car that would go 100,000 miles at least; HEY $35,000 its alot of money, witch brings me to my point: if were the average buyer in the average dealer, If the car made no power below 3000 Rpms it will have been a very low fun factor and dissanpointing to many potential buyers, and most people in this forum will pobably disagree,** But Mazda intended Rx-7`s to be driven daily, in traffic and survive regular duties for at least until the warranty weared out**.
So if you ever wondered wich is better it is up to you to deside, there`s no absolute reason and the relativity of their differential factors are inconclusive. Mazda had it s reasons to like seq. We have our own reasons as sport car owners to deside what we like. Pistons or rotors,vanilla or chocolate,decaf or nondecaf....
Thank you for reading boring my thread

PEACE

 

I know that since switching to non-seq. a year ago I've had to live with a different driving style. You definitely have to downshift more. 5th gear is completely useless at normal driving speeds. I used to have a 89 MX-6 GT Turbo - 145 hp..it had power in any gear I was in but it was not crazy fast..it just seemed like it had boost anytime..a sequential FD has endless boost, anytime in any gear - even 5th gear. I could smoke the typical Honda on a highway roll of 50-70 in 4th gear by many cars - maybe even in 5th gear. But if you are non-seq., cars will pull you if you drive in the higher gears. BUT, if you are in the right gear and in the powerband, a non-sequential car will pull a sequential car period. Like earlier stated, if you have the right mods to go along with running NS and you had a sequential car beside it and you rode in both, the NS car will pull harder. On a backroad, a sequential car will be more fun to drive from 2500 rpm punches in 2nd gear around a tight turn. But switching over to NS turns the FD (with some decent mods) into a car that compete with a small or medium single turbo FD. I'll be posting a dyno sheet with upgraded twins running NS in late August - should be interesting.

 

I found some more dyno results: cew's full-ns run at 12 psi, exh porting. And Tim Benton's 12.5 psi run with a properly set-up stock sequential with stock ports. With PFC, he had the transition advanced by 500 rpm.

https://www.rx7club.com/forum/showth...ght=transition

Brad and Brian data from Brian's prev linked site.

hp table:

rpms -- Bria Cew -- Bra Tim

3000 -- 090 105 -- 120 130
3500 -- 133 145 -- 137 160
4000 -- 180 185 -- 160 180
4500 -- 220 220 -- 185 220
5000 -- 250 240 -- 243 260

psi --- 12.3 12 -- 12 -- 12.5

The two NS runs are similar.

Tim's seq run shows how much hp can be available up thru 4000 rpm if primary boost is kept at same level as secondary (Brad had lowr boost on primary). His run also shows the benefit of early transition by way of PFC, as I had previously noted.

This is not to imply anything other than a very health hp curve can be achieved with sequential at about 12 psi boost, with a little help from the PFC.

-------------------

As far as engine life, seq vs ns, likely more related to other things. But, the turbine housings will have fewer thermal cycles and less severe heat gradients with NS, and should see less cracking, especially with hard use.

 

I have to agree with kevin here. I don't know how flexible the PFC is, but I have all my seq solenoids rigged up to outputs on my EMS. I have tried the non-seq setup (charge releif closed on boost;charge control open; turbo control on) and to be honest I think it sucks compared to a well sorted seq system. I found non-seq to be loud (as in the whole car just boomed) it had a gutless, laggy lowend, and secondary spoolup was weak. Oh yeah and it sounded like **** off-boost.

The seq setup I run is (charge releif on until 4400;precontrol staged from 3500 to 44000;charge control totally on at 4250;turbo control on a 4400rpm) this gives me a solid 14psi from about 2250rpm right through to 7750.

IMHO it's worth saving your money for a standalone. Non-seq is poor because you can't parallel two unbalanced turbo's. The primary has major trouble spooling because it's trying to pressurize the secondary turbo's outlet. The secondary takes all day to spin up because it's pushing against air from the secondary.

-pete

 

what i would like to see is a nice easy to read clear torque and power dyno sheet of a seq qith mods, then the guy switch over to ns and copare the two dyno sheets with the same car and see with is the best

 

Ok, I going to jump in here because I've done both setups.

Non-sequential pros:
-----------------------------
1. Simple, smooth, good midrange power
2. Increased secondary turbo life
3. Easy to launch and predictable in corners

Non-sequential cons:
---------------------------------
1. More downshifting (personal preference here, I happen to enjoy being lazy!)
2. Need intake, 3" exhaust (mp or high-flow cat), and IC upgrade to really take full advantage

Sequential pros:
-----------------------------
1. Fast turbo response
2. Good low end power

Sequential cons:
-----------------------------
1. Complicated rats nest with known problems
2. Nasty transition when secondary turbo comes online

Additional comments:
--------------------------------
The fun factor of sequential can't be denied. It is effortless to drive as you get boost immediately. While the transition spike has been known to blow motors from overboosting, the feeling of being shot out of a cannon is just plain fun. I used to find myself going in and out of secondary turbo mode just for that kick! The impromper transition is the source of many headaches. I really think with proper adjustment through the tuning tools that are available now (PowerFC w/ datalogit) that this transition could be much more effective and stable now. You can lower the transition point in the rpm range and adjust fuel accordingly. If you study the PowerFC maps you will learn how much extra fuel is there to dampen the boost spike. I do believe 100% that this excess fuel is also one of several reasons the power curve has a flat spot in it. With that being said I think there is power to be gained and a smoothness to be obtained.

Now with non-sequential the car becomes very smooth and predictable. The car is super easy to launch and just pulls all the way to redline. The car ran much cooler with non-sequential (full).

 

I'm sure your a great guy in real life and everything but, I dont agree with you, I said "you runing faster that riki's times it was not because your seq's", what I meant by that is you probly have a better set of turbos, or eng, or tires (worn nitto are slicks), or it was colder, or track condition ect...

I am saying that if you keep "your" car the way it you will be faster if you put them non seq drag(yes drag) or street . If you belive you all of your actuators and solenoids keep both you turbos on at the same time above 5000 you are fooling yourself. They go through a sequence ever time you shift, if you rev to 5000 at launch you will not stay above 5000 when your tires lock... You will notice a difference especially at launch. SMALL AS IT MAY BE IT IS THERE.

All these times from different cars are 100% usless not all engines, turbines, tires, wheater cond's, and clutchs are not created equal. The self-proclaimed Little Fatso Skitzo Wop Deago is right, we need dyno numbers from the same car for them to mean ANYTHING.

If you take "YOUR" car with the same mods it has now and run non-sequential you will be faster in the 1/4.

If you are tring to max tune your stock turbos non is the way yo go as far as power(yes I said power) and and even more so relighability.

 

I've been thinking - is there a happy compromise?

What if you could rig up the secondary turbo to open it's own gate when it's ready. I was thinking like this:

Charge control
------------------
vacum side: vent to air
pressure side: connect to secondary 4mm nipple

***This should allow the secondary turbo to BEGIN opening the shutter valve as it starts to make positive pressure - a big failure of the NS system

Charge releif
----------------
remove - as soon as the 2ndary is making good boost I want it to start pumping anyway

Turbo control
----------------

vaccum side: vent to air
pressure side: connect to 2ndary outlet where the charge releif was connected

** as the secondary starts to make good boost it moves it's own turbo control thus engaging itself.

Wastegate
--------------
as-is

pre-control
--------------
I have this mapped into the ECU solenoid maps. I may later convert this to a simple t-piece arrangement to get the secondary to spool only once the primary hits *say* 10psi not 7psi that you would get with a direct connection

I am going to play around with this tonight. Any ideas? suggestions?

-pete

 

pete(rpm pwr)- Holy Crap!! You should make a new thread on this. That is far too intellectual for this thread. On this one we are busy beating a dead horse bickering on page 3 about the same thing we were on page 2. I dont want to see your intellengent though get burried in this thread behind our bickering.

Sounds like a win win if you can get it to work keep us posted.

Especially if you do it without a ECU solenoid remap! We(most of us anyway) are a simple folk that cant read hex code off the top of our heads and most of us dont even have yer basic eprom reader/writers. Jesse

 

well! im proud to be the starter of bitch fest 2002 lol thanks for all your thoughts

 

Question
Will going non-seq help me feel the rush in the freeway passing, changing lanes, real world cruising stuff. will it?

 

Sure it will, you just have to downshift to get your car in its power band, kind of like any other "regular" car. Non-seq will make 5 and 4th gear somewhat useless for passing unless you have plenty of room to do so. Remember that with NS it will take to about ~3,800 RPMs to build full boost .

 

What sequence do they go thru eveytime I shift? Lets say for the sake of arguement that they do drop back to seq mod when I shift. Maybe thats why I have a INSTANT 14psi of boost at everyshift and with a nonseq set up your waiting for boost. Maybe not along time but while seq is at full boost and taking off non seq is still building boost. I'm sure that's enough to make up for any short comings. Just because nonseq gets more power from 3500-4500 doesnt mean a whole lot because the seq had more power from 2500-3500....when nonseq gets to 3500 and starts making more power its going to be needed because its playing catch up. By the time nonseq catches up they are at 5K and running even.

You might think I'm kidding myself but if you think he gained 4mph in the 1/4 bcause of nonseq your kidding yourself. If anything its because he couldnt drive the seq sys the way it needed. He had enough mods to hit 117 in the 1/4 with either set up, if he couldnt it wasnt because he was seq its cause launching with nonseq takes less skill. (Sorry Rikki, i'm not trying to be ugly, please dont take this the wrong way)


It just seems to me no matter what kind of racing, the seq is going to get it off the start with instant boost while the nonseq is building boost.

Anyway, I see it one way, you see it another it doesnt really matter we can agree to disagree. Believe it or not I'm really not a die hard seq guy I just think you guys are after nonseq for the wrong reasons. Like Spyfish said the transition point can be made smoother, even with just a set of home depot boost contollers so you get a small spike instead of a dip which is what i do.

STEPHEN

 

I agree. Spyfish's post was cut,clear, dried, and is exactly what I experience in non-seq.(Xlnt post, btw.) You wanna street launch or load up for passing, you're gonna have to downshift/rev it into the spooling powerband like any other single turbo car. It's par for the course and unfair to compare to sequential. It comes down to system complexity, convenience, and preference in the end. Those who've driven other turboed cars know what I mean.

Watch for the "Instant boost spike" with any mods, tho...

 

Well lets see here I'm running....

intake, dp, mp, catback, upgraded IC (like the M2 med but customs by me), all alum pipes and greddy elbow, 850pri/1200sec, Walbro pump, street ported engine, Power FC with datalogit, 15psi of boost, 4 puck clutch short throw shifter, springs, toe links, trailing arms, anti sway bar, tower strut brace, and I'm sure some more that I'm forgeting....

I'm sure that should be enough to validate my knowledge

what mods are you running???

STEPHEN

 

Man, I've been to your website and you have a nice car and site, I pretty much know what all you have but it doesnt really matter to me what you have or dont have, this isnt about who has more or less. I wasnt trying to attac you or anything that why I said........(Sorry Rikki, i'm not trying to be ugly, please dont take this the wrong way). That post wasnt even to you but I knew you would be reading it so I threw that in there. I didnt want you to get the wrong impression that I'm saying anything bad about you or your car. I dont mean it as a personal attack, I just feel you prob could have got the same resuls with seq if it would have been driven a different way. Different people drive different, if nonseq work for your style better than thats good. Honestly I think driving technique explains the 1/4 times better than saying its cause of more power, personally I dont think it was from extra power. You might have even had a seq problem, i had a boost leak on time but still made a solid 12psi of boost all the way thru rpms but it just didnt feel the same till I fixed the prob.

That being said we can agree dissagree on the subject and not have it come down to a pissing contest that I'm not interested in anyway. If you guys think it is from extra power thats great but doesnt explain other people traping as fast and faster on seq set up. I'm just saying I dont think its from extra power but you dont have to think that. You are more than entitled to think what ever you want but if you guys are telling everyone a certain thing I'm also going to throw in my .02 also that way they have both OPINIONS to think about.

I also showed my 1/4 times earlier in the thread. With just intake, full exhaust, PFC running stock maps and 12-13psi of boost I ran a 12.3 @ 113, EVERYTHING else was bone stock down to the clutch but I was running some Nittos. I havent been back to the track since but can tell you all the other mods I have listed have helped alot and the car is much faster (till I loaded a XS map anyway but thats currently being taken car of)

Later,
STEPHEN