Non-seq and seq?
Non-seq and seq?
I'm pretty new to the FD section, but I was wondering what everyone is talking about with these non-sequential and sequential turbos. Non-sequential is where the boost kicks in twice right 10-8-10? That's how the FD is stock, but there is a way to make them sequential and have both turbos pushing at the same time all the time?
What's the advantages and disadvantages of this? Why do people run sequential rather than non-sequential, etc.
What's the advantages and disadvantages of this? Why do people run sequential rather than non-sequential, etc.
Be a Hero...Punch a Koala
Joined: Aug 2005
Posts: 1,022
Likes: 0
From: Evansville, IN
Reverse your theories and you'll ahve it
Sequential= Stock 10-8-10
Non-Sequential=Conversion both pushing at the same time.
http://www.fd3s.net/non-sequential.html#PAR
https://www.rx7club.com/showthread.p...ght=Sequential
https://www.rx7club.com/showthread.p...ght=sequential
Just to get you started.
Sequential= Stock 10-8-10
Non-Sequential=Conversion both pushing at the same time.
http://www.fd3s.net/non-sequential.html#PAR
https://www.rx7club.com/showthread.p...ght=Sequential
https://www.rx7club.com/showthread.p...ght=sequential
Just to get you started.
Okay, well it seems as though I should be running non-sequential according to that website once I get a midpipe.
Running non-sequential though, won't that burn more gas since both turbo's run at the same time? Will it increase HP at all or just a smoother power curve.
Running non-sequential though, won't that burn more gas since both turbo's run at the same time? Will it increase HP at all or just a smoother power curve.
Passenger
Posts: n/a
Sequential is stock. (Sequence = turbo #1 spools, then turbo #2 spools; 10-8-10)
People run non sequential because it is simpler (and other run it because they don't like the double turbo transition). In my opinion sequential is infinitely better (though it is a complicated and fragile system) because it combines the power of a larger turbo with the qucik spooling of a small turbo. That was the original intention, after all. Twin sequential turbos are more difficult to control in a race track, but the rewards are much greater once you master it.
Many people go with the "big brute" single turbo setup (non sequential because there is only one turbo) as an alternate to the non sequential twins, and it acts in a similar fashion as that. There is only one spool up period and thus only one transition period and thus a little more manageable to some people. Many drag racers employ this on the premise that "bigger is better" and faster. The same philosophy, I liken, to the big displacement philosophy.
Sequential > Non/Single
People run non sequential because it is simpler (and other run it because they don't like the double turbo transition). In my opinion sequential is infinitely better (though it is a complicated and fragile system) because it combines the power of a larger turbo with the qucik spooling of a small turbo. That was the original intention, after all. Twin sequential turbos are more difficult to control in a race track, but the rewards are much greater once you master it.
Many people go with the "big brute" single turbo setup (non sequential because there is only one turbo) as an alternate to the non sequential twins, and it acts in a similar fashion as that. There is only one spool up period and thus only one transition period and thus a little more manageable to some people. Many drag racers employ this on the premise that "bigger is better" and faster. The same philosophy, I liken, to the big displacement philosophy.
Sequential > Non/Single
Originally Posted by HardHitter
I'm pretty new to the FD section, but I was wondering what everyone is talking about with these non-sequential and sequential turbos. Non-sequential is where the boost kicks in twice right 10-8-10? That's how the FD is stock, but there is a way to make them sequential and have both turbos pushing at the same time all the time?
What's the advantages and disadvantages of this? Why do people run sequential rather than non-sequential, etc.
What's the advantages and disadvantages of this? Why do people run sequential rather than non-sequential, etc.
Also: http://www.micromanx.com/goble/rx7/p...3/nonseq3.html
You have the nomenclature backwards; sequential is where one gets a boost pattern like 10-x-10 psi. The FD is set up from the factory like this to improve response below 4500 RPM. Non-seq pretty much eliminates the low end power and gives you the top end on about the same level as the sequential system.
Non sequential turbos are usually used when either a) an FD owner can't figure out his/her sequential turbo system boost/control issues; or b) an FD owner is prepping his/her car for a single turbo conversion. You can think of the non-seq conversion as a sort of small single turbo.
There's a lot of info on this forum... search and learn
PS Check out this link for dyno charts of sequential, non-sequential, and single turbo cars. It will give you a better idea of what the power curves look like for each type of turbo setup.
http://dyno.zeroglabs.com/dyno.php
EDIT: a few other chimed in before me with good info, I managed to echo what they said...
Last edited by mdpalmer; Dec 27, 2005 at 02:31 AM.
I think since my car is running fine it'd be better just to stick with seq. turbos. Again, like some said, the only downfall would be the "kick" when the second turbo kicks in if you arn't expecting it, control could be a factor but I like having the low end power as somewhat "torque"
omgwtfposlol
Joined: Dec 2002
Posts: 862
Likes: 0
From: Orange City, FL
Originally Posted by AcesHigh
Twin sequential turbos are more difficult to control in a race track, but the rewards are much greater once you master it.
you are wrong.the sequential system doesn't revert to single operation untill you are under 3k rpm once you have transitioned to twin. so, on a car such as ours with an 8k redline and barely any displacement, on what track do you think you'd be under 3k? even with one turbo spooled to 10psi, under 3k you aren't making much power.
so how is the sequential system more rewarding on a track? they drive exactly the same on a track stock. and modded, where you can spool both turbo's earlier, you're losing time waiting till 4500 for the second turbo.
sequential is for daily drivers that can't downshift, like automatics. on the track it's the same, and the more modded you get, the more going non-seq comes into favor.
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Passenger
Posts: n/a
Originally Posted by particleeffect
so how is the sequential system more rewarding on a track? they drive exactly the same on a track stock. and modded, where you can spool both turbo's earlier, you're losing time waiting till 4500 for the second turbo.
omgwtfposlol
Joined: Dec 2002
Posts: 862
Likes: 0
From: Orange City, FL
Originally Posted by AcesHigh
Autocrosses. Road racing. Not all courses are giant course monsters. Spooling two turbos at once is much slower than each one sequentially. You are incorrect in assuming that they are both the same on a course. Single/non seq is very peaky.
this is old ****, it's been discussed to death. in a racing application they drive the same over 3k, where you generally will stay anyway. and the more modded you get, the sooner you can spool both turbo's, so you'd just waste more and more time waiting for transition.
you don't seem to understand much about how the sequential system works.
like i already said, sequential is for street/automatic cars. the idea that it will be more "rewarding" on a racetrack (and modded car) and more peaky is pure ignorance. you are incorrent in assuming that a non-seq/single car is more peaky, and it only shows how little you understand about how seq works. and there are such things as "small" singles you know, you're incorrect again to assume they are all "big" lag monsters.
Passenger
Posts: n/a
Originally Posted by particleeffect
what you don't seem to understand is that a well modded car CAN spool both turbo's well before 4500rpm. so a non-seq car would be faster there. furthermore, it is no more peaky that sequential, because believe it or not, after transition you aren't likely do go under 3k. and your probably not going under 3k on a road course, because you generally have time to downshift. some autoX courses might have you around 3k in 2nd, but then you are going to have to deal with the 50+hp kick transition gives you anyway. hardly the definition of smooth.
this is old ****, it's been discussed to death. in a racing application they drive the same over 3k, where you generally will stay anyway. and the more modded you get, the sooner you can spool both turbo's, so you'd just waste more and more time waiting for transition.
you don't seem to understand much about how the sequential system works.
like i already said, sequential is for street/automatic cars. the idea that it will be more "rewarding" on a racetrack (and modded car) and more peaky is pure ignorance. you are incorrent in assuming that a non-seq/single car is more peaky, and it only shows how little you understand about how seq works. and there are such things as "small" singles you know, you're incorrect again to assume they are all "big" lag monsters.
this is old ****, it's been discussed to death. in a racing application they drive the same over 3k, where you generally will stay anyway. and the more modded you get, the sooner you can spool both turbo's, so you'd just waste more and more time waiting for transition.
you don't seem to understand much about how the sequential system works.
like i already said, sequential is for street/automatic cars. the idea that it will be more "rewarding" on a racetrack (and modded car) and more peaky is pure ignorance. you are incorrent in assuming that a non-seq/single car is more peaky, and it only shows how little you understand about how seq works. and there are such things as "small" singles you know, you're incorrect again to assume they are all "big" lag monsters.
The twin turbo system is rewarding in that in the complete mastery of the system you learn delicate throttle technique as well as RPM manipulation. In the long run, your lack of lag compared to a large single turbo and ultimate power compared to a small single turbo becomes the better system.
The single turbo setup is better suited for a straight line racing situation as there is a smaller pressure drop during upshifts.
Let's entertain a conceivable situation here. The Mazda Laguna Seca track is full of hairpins, sharp turns, and the dreaded corkscrew. It also has long straightaways between these corners. Would you rather take a small T3 single, a large T88 single, or a sequential BNR Rx-7?
I would take the BNR.
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