Sequential vs. Non Sequential
02-17-22, 08:55 PM
#1
Sequential vs. Non Sequential
enjoy
all the graphs are below. i only want to mention that there is a discrepancy with the data which is forcing this comparison to be redone. the data shown on at the dyno the day we did this vs what is actually on the sheets just doesnt match. the bolt on car wont be available for the retest but the other 2 will.
its going to be some time before we can do it again but we WILL be doing it again. outside of that...... hopefully this thread will be a great addition to anyone's research in doing the mod.
all the graphs are below. i only want to mention that there is a discrepancy with the data which is forcing this comparison to be redone. the data shown on at the dyno the day we did this vs what is actually on the sheets just doesnt match. the bolt on car wont be available for the retest but the other 2 will.
its going to be some time before we can do it again but we WILL be doing it again. outside of that...... hopefully this thread will be a great addition to anyone's research in doing the mod.
Spoiler
The following 4 users liked this post by cr-rex:
The following users liked this post:
djseven (02-19-22)
The following users liked this post:
Testrun (03-09-22)
Trending Topics
02-17-22, 11:41 PM
#9
Well I just click on the link and it takes me to my YouTube app, I don’t see anything but a video… am I missing something?
Either way, those number @5:33 is the main point right? Are those number supposed to be good? For reference my seq twins reach 12psi at 3400rpm, you hit 10psi where? 🤔
Either way, those number @5:33 is the main point right? Are those number supposed to be good? For reference my seq twins reach 12psi at 3400rpm, you hit 10psi where? 🤔
Last edited by ZE Power MX6; 02-17-22 at 11:58 PM.
02-18-22, 05:27 AM
#10
Senior Member
iTrader: (2)
Well I just click on the link and it takes me to my YouTube app, I don’t see anything but a video… am I missing something?
Either way, those number @5:33 is the main point right? Are those number supposed to be good? For reference my seq twins reach 12psi at 3400rpm, you hit 10psi where? 🤔
Either way, those number @5:33 is the main point right? Are those number supposed to be good? For reference my seq twins reach 12psi at 3400rpm, you hit 10psi where? 🤔
Interesting test and glad you delivered. Look forward to what folks say.
02-18-22, 08:03 AM
#11
^ That doesn't work on the phone, it just show 2 bold words of spoiler lol, I can see it on my PC now.
So... these cars are running different boost, right? Comparing the Non-seq graph to mine, since our boost level is the same, I have more power under the curve everywhere + more peak... And where's the torque curve? Mine hit 250lb/ft before 3500rpm @12psi
So... these cars are running different boost, right? Comparing the Non-seq graph to mine, since our boost level is the same, I have more power under the curve everywhere + more peak... And where's the torque curve? Mine hit 250lb/ft before 3500rpm @12psi
The following users liked this post:
gdub29e (02-18-22)
02-18-22, 08:53 AM
#13
like most yoobube vids, it doesn’t prove anything more than how easily people fall for believing everything they see and hear rather than critically applying their brain to it’s full potential
which before the usual suspects start pointing and screaming debbie-downer, I don’t really mean anything against the people who made it, but the more the system and process coupled with the social vulnerability of the masses and human nature in general
I honestly thought the guys in it are pretty cool and even agree with the one guy about a single should with today’s technology be able to potentially best a twin sequential in a number of ways, though the lower the boost level the more in favor of the twins it will be imo
just that maybe it wasn’t gone about in the right way, but kind of guessing about that since they don’t really provide any details about the contender vehicles. Just seems like they grabbed a couple of modded contenders rather than somebody setting out with the explicit intention of doing it with the necessary components and resources.
but that’s just a bunch of personal opinion and swag based on watching some yoobube vid.
one of the more recent threads on it, as usual lots of diversity in opinions, but will add that being in a situation recently with someone near and dear to my heart, will pose this question: what by any other name is an “opinion” that’s based on mistruth, whether intentional or not, whether believed in sincerity or not?
https://www.rx7club.com/3rd-gen-gene...ingle-1155066/
.
which before the usual suspects start pointing and screaming debbie-downer, I don’t really mean anything against the people who made it, but the more the system and process coupled with the social vulnerability of the masses and human nature in general
I honestly thought the guys in it are pretty cool and even agree with the one guy about a single should with today’s technology be able to potentially best a twin sequential in a number of ways, though the lower the boost level the more in favor of the twins it will be imo
just that maybe it wasn’t gone about in the right way, but kind of guessing about that since they don’t really provide any details about the contender vehicles. Just seems like they grabbed a couple of modded contenders rather than somebody setting out with the explicit intention of doing it with the necessary components and resources.
but that’s just a bunch of personal opinion and swag based on watching some yoobube vid.
one of the more recent threads on it, as usual lots of diversity in opinions, but will add that being in a situation recently with someone near and dear to my heart, will pose this question: what by any other name is an “opinion” that’s based on mistruth, whether intentional or not, whether believed in sincerity or not?
https://www.rx7club.com/3rd-gen-gene...ingle-1155066/
.
Last edited by TeamRX8; 02-18-22 at 09:08 AM.
02-18-22, 10:24 AM
#14
Maybe it's just me but I dont entirely understand what you're saying. Theres a full mod list for each car in the video. What do you mean they do go over each car? It's also explained right in the beginning WHY each car was chosen. There was nothing random about the test
02-18-22, 02:25 PM
#15
RX-7 Bad Ass
iTrader: (55)
I think you are on the right track here but I think your methodology needs a little work.
Really the PSI of boost is irrelevant and top end power is irrelevant - it's known that you can make some more power on the top end going non-sequential.
The difference is TORQUE. Really need to overlay the torque from each car from 2000 to 4000 RPM. Also, yes, *2000 RPM* - this is where sequential comes into play, you want that immediate spool up down low. I don't think you ran the cars at that low of an RPM though. I know a few of the pulls I saw were starting at higher RPM. Torque will show how well the car digs in and goes at low RPM which is the difference with sequential versus non-sequential.
If you can get a copy of the log files from the Dynojet you can download Dynojet's free software that will let you import the files, over lay them, play with the view, all that good stuff. The dyno charts that are up are VERY hard to read and make hard sense of.
I do appreciate you putting the effort into this! There also are other factors - I don't think that stock FD was running 100% with how ratty the top end of the dyno looks (maybe needs plugs or coils) - basically all cars need to be on a fairly level playing field.
I also defer to peopl@djseven who has driven HUNDREDS of FD's in all different configurations and can tell the experience of driving a properly running sequential car.
Thanks!
Dale
Really the PSI of boost is irrelevant and top end power is irrelevant - it's known that you can make some more power on the top end going non-sequential.
The difference is TORQUE. Really need to overlay the torque from each car from 2000 to 4000 RPM. Also, yes, *2000 RPM* - this is where sequential comes into play, you want that immediate spool up down low. I don't think you ran the cars at that low of an RPM though. I know a few of the pulls I saw were starting at higher RPM. Torque will show how well the car digs in and goes at low RPM which is the difference with sequential versus non-sequential.
If you can get a copy of the log files from the Dynojet you can download Dynojet's free software that will let you import the files, over lay them, play with the view, all that good stuff. The dyno charts that are up are VERY hard to read and make hard sense of.
I do appreciate you putting the effort into this! There also are other factors - I don't think that stock FD was running 100% with how ratty the top end of the dyno looks (maybe needs plugs or coils) - basically all cars need to be on a fairly level playing field.
I also defer to peopl@djseven who has driven HUNDREDS of FD's in all different configurations and can tell the experience of driving a properly running sequential car.
Thanks!
Dale
The following 5 users liked this post by DaleClark:
djseven (02-19-22),
Jatt (02-18-22),
madhat1111 (02-19-22),
nashman69g (02-18-22),
ZE Power MX6 (02-18-22)
02-18-22, 04:10 PM
#16
Right on Dale, we need to see the torque curve, BUT even the HP number are unimpressive under 4500RPM in the non-seq chart. Actually PSI vs RPM is relevant, the sooner you make full boost at low RPM the faster you get going, more power under the curve.
02-18-22, 05:28 PM
#17
First thank you for coming through with your word. But I'm a little confused on what you were trying to prove.
In the video you stated: "they said it couldn't be done and we are going to find out whether it works or not. The big debate is sequential vs non-sequential ". What couldn't be done??? "Most believe the ultimate form of the FD is the sequential setup". I'm not sure who has ever said that but it really all depends on what the goal of the car is.
Maybe I misunderstood, but is your video in response to this thread?:
https://www.rx7club.com/3rd-gen-gene...eo-fd-1154838/
My post there:
As getgone stated plus and minuses between both setups. I'm sure you know all this but I'll say it anyway...
Non sequential:
Sequential:
I completely understand your point of view. I purchased my 100% stock FD with a perfectly working sequential but after a while I stared having boost issues here and there (they would get fixed although quite annoying). So knowing that my vacuum lines were old and brittle, I decided to replace all of them. It fixed the reoccurring issues for about three years which was great but after that, I started seeing signs that they were getting brittle again. Back then (2004ish time) there were quite a few debates here because "some" people swore that their non-seq setup would get "identical" boost threshold as the sequential system, you just had to have all the right mods (CAI, DP, MP, catback & an upgraded SMIC (short piping)). So not wanting to deal with the vacuum hose replacement again and since I had supposedly had all the right mods, I decided to give non-sequential a try. My finding was that those non-sequential people were full of it. My boost threshold was at 3800RPMS and laggy to boot. Exactly what many said it should be.
The real life test came when I raced my childhood friend who had a porsche boxster. We used to race each other all the time and prior to going non-sequential I would leave him in the dust the minute I smashed the gas pedal. After going non-seq, he would leave me behind by 1 1/2 cars before my turbos would hit full boost. So I was left playing catch where I would reel him in and pass him eventually. I remember my friend asking "So why did you do that to your car?" lol. The reality was that although my car was at the same boost level and had a larger DUAL turbo power band increase (non seq 3800-8000RPM vs seq 4500 - 8000RPM), the car's performance was actually hindered. It's too laggy and it lacks the primary turbo power band (2800-4450RPM) that really helps in getting the car moving. But on the upside I never had a boost issue again. Now my car is single turbo, has a much better boost threshold 3300RPMS (GT35R), it has more power, and it is a lot more responsive when compared to when it was non-sequential.
In terms of reliability the only reason go non-sequential is if there is a lack of funds to go single and/or smog issues. It just doesn't make sense otherwise because the fun factor of non-seq kinda sucks in comparison to a nice single or a properly working sequential system.
Non sequential:
- Predictable boost response even at higher boost levels (12+psi)
- Only 6 vacuum hoses and therefore very easy to trouble shoot
- Has a boost threshold of around 3800 RPMS (boost threshold is different from lag, boost threshold is the RPM where the turbos see enough exhaust gas to become "alive")
- Laggy setup (This is the time it takes for the turbos to hit full boost after they become "alive")
- Might as well go single turbo as dj said, these days singles have a much better boost threshold, spool faster, and provide more power.
Sequential:
- Primary turbo boost threshold of 2800 RPMS, dual turbo threshold of 4500RPMS.
- Fast spool boost (10psi in an instant anytime after 2800RPMS)
- Perfect for street cars
- Has 72 vacuum hoses which are known to cause a lot of issues when they get old
- Complex. When something becomes compromised it can be a daunting task to find the issue (people have been known to just give up on fixing it)
- Involves having a not so seamless secondary turbo transition at 4500RPMS where as you saw that it can cause spinouts. Not only that, it also gets tricky to control boost response at higher levels (12+psi). What I mean by tricky is that at the transition, you can see boost spikes of several psi before it settles to whatever your boost is set at.
I completely understand your point of view. I purchased my 100% stock FD with a perfectly working sequential but after a while I stared having boost issues here and there (they would get fixed although quite annoying). So knowing that my vacuum lines were old and brittle, I decided to replace all of them. It fixed the reoccurring issues for about three years which was great but after that, I started seeing signs that they were getting brittle again. Back then (2004ish time) there were quite a few debates here because "some" people swore that their non-seq setup would get "identical" boost threshold as the sequential system, you just had to have all the right mods (CAI, DP, MP, catback & an upgraded SMIC (short piping)). So not wanting to deal with the vacuum hose replacement again and since I had supposedly had all the right mods, I decided to give non-sequential a try. My finding was that those non-sequential people were full of it. My boost threshold was at 3800RPMS and laggy to boot. Exactly what many said it should be.
The real life test came when I raced my childhood friend who had a porsche boxster. We used to race each other all the time and prior to going non-sequential I would leave him in the dust the minute I smashed the gas pedal. After going non-seq, he would leave me behind by 1 1/2 cars before my turbos would hit full boost. So I was left playing catch where I would reel him in and pass him eventually. I remember my friend asking "So why did you do that to your car?" lol. The reality was that although my car was at the same boost level and had a larger DUAL turbo power band increase (non seq 3800-8000RPM vs seq 4500 - 8000RPM), the car's performance was actually hindered. It's too laggy and it lacks the primary turbo power band (2800-4450RPM) that really helps in getting the car moving. But on the upside I never had a boost issue again. Now my car is single turbo, has a much better boost threshold 3300RPMS (GT35R), it has more power, and it is a lot more responsive when compared to when it was non-sequential.
In terms of reliability the only reason go non-sequential is if there is a lack of funds to go single and/or smog issues. It just doesn't make sense otherwise because the fun factor of non-seq kinda sucks in comparison to a nice single or a properly working sequential system.
IIRC correctly the debate is about how unresponsive the non-sequential set up is and you proved it. Exactly as we said, the non-sequential car is laggy AF.
Sequential stock car:
- WOT at 2500 RPM get 10 psi by 3200RPM (700 RPM)
- WOT at 3000 RPM get 10 psi by 3500RPM (500 RPM)
- WOT at 3500 RPM get 10 psi by 4100RPM (600 RPM)
- WOT at 2500 RPM get 10 psi by 3500RPM (1000 RPM)
- WOT at 3100 RPM get 10 psi by 4000RPM (900 RPM)
- WOT at 3600 RPM get 10 psi by 4500RPM (900 RPM)
- WOT at 2400 RPM get 10 psi by 4100RPM (1700 RPM) over 2x less responsive than the stock car at 2500 RPM
- WOT at 2600 RPM get 10 psi by 4200RPM (1600 RPM) over 2x less responsive than the stock car at 2500 RPM
- WOT at 3100 RPM get 10 psi by 4300RPM (1200 RPM) over 2x less responsive than the stock car at 3000 RPM
- WOT at 3300 RPM get 10 psi by 4400RPM (1100 RPM) close to 2x less responsive than the stock car at 3500 RPM
On a side note: Now I haven't been in a stock sequential car in many, many years but I remember my car was much more responsive than both of your sequential examples. If I WOT at anytime above 2800RPMs I was at 10psi immediately and I mean immediately. These cars seem very laggy to me but like I said it has been many years since I was sequential.
Last edited by Montego; 02-18-22 at 07:33 PM.
02-19-22, 02:33 PM
#18
Having had a non-sequential FD in the past, I can without a doubt say that setup sucks. It is laggy and unimpressive.
My current car reaches 12–13psi in an instant no matter where I’m at in the power band. Sequential is absolutely the best setup without going with some EFR turbo setup. However, I’ve yet to ride in any EFR turbo RX-7s!
My current car reaches 12–13psi in an instant no matter where I’m at in the power band. Sequential is absolutely the best setup without going with some EFR turbo setup. However, I’ve yet to ride in any EFR turbo RX-7s!
The following 3 users liked this post by twinturborx7pete:
The following 2 users liked this post by djseven:
gdub29e (02-20-22),
ZE Power MX6 (02-19-22)
02-20-22, 12:32 AM
#20
Thanks for posting, I wouldn't have thought to start the dyno runs at various RPM like that. I'd love to see the data logs if you've got RPM and MAP and Throttle logged at reasonable rates.
I could see the argument for non-seq if you're always drag racing and able to keep the RPM above 5000 after shifts. For autocross and track days I've seen below 3000 RPM coming out of slow corners when I wasn't quite comfortable downshifting. Better drivers might be able to work around a powerband with less low-end torque, but average and below-average drivers (like me) probably need the low and mid-range power.
If you're trying to go fast, I think you should look at tire speed vs time, for instance how many seconds did it take the sequential car to get from 3000 RPM to 8000 RPM and how does that compare to the non-seq car? Remember that the non-seq car is not just taking more RPM to reach full boost but its also accelerating more slowly and taking longer to get out of that 2500-4200 RPM range.
I could see the argument for non-seq if you're always drag racing and able to keep the RPM above 5000 after shifts. For autocross and track days I've seen below 3000 RPM coming out of slow corners when I wasn't quite comfortable downshifting. Better drivers might be able to work around a powerband with less low-end torque, but average and below-average drivers (like me) probably need the low and mid-range power.
If you're trying to go fast, I think you should look at tire speed vs time, for instance how many seconds did it take the sequential car to get from 3000 RPM to 8000 RPM and how does that compare to the non-seq car? Remember that the non-seq car is not just taking more RPM to reach full boost but its also accelerating more slowly and taking longer to get out of that 2500-4200 RPM range.
02-20-22, 11:41 AM
#22
😂 You nailed it. Sometimes being direct & succinct is the best response. Mike seems like a genuine & cool guy so my attempt to not come off rude just ended up being long winded.
02-20-22, 12:31 PM
#23
Lol. I applaud the effort and he seems like a great guy. I’ve definitely put more FDs back together NS probably 10:1 to sequential. The simplicity is great but besides 8-10 more rwhp up top the benefits disappear quickly. The driving experience is no where near as enjoyable when NS either. I’m just glad to see guys driving and beating on them.
