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-   -   parallel vs. sequential (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/parallel-vs-sequential-675724/)

dgeesaman Apr 29, 2009 05:06 AM


Originally Posted by jhowell (Post 9166492)
if people so worried bout lag y not run a small 50 hp shot of nitrous im just wondering

A 50 shot is reasonable as long as you can keep things tuned with enough fuel.

Dave

gracer7-rx7 Apr 29, 2009 09:03 AM


Originally Posted by jhowell (Post 9166779)
yea gotcha it seems like gettin to 3500 rpm isnt hard wut do rx7s idle at? 2k?

Mine idles at 840 RPM

Do you even own an RX7?

JDMinard Apr 29, 2009 09:35 AM


Originally Posted by jhowell (Post 9166779)
yea gotcha it seems like gettin to 3500 rpm isnt hard wut do rx7s idle at? 2k?

Its not everyone thats has a monster port idling at 2k, lol

Anyway, does anybody want to go full non-seq in a near future in this forum?
So dyno it before/after!!!!!!!!
I want some real proof, ill stick with seq till someone show me a 10hp+ of diff. ( yeah right)

Edit: seriously even with a 3-5hp gain, dont waste your time and money, go single if you really want power

djseven Apr 29, 2009 09:50 AM


Originally Posted by gmonsen (Post 9164695)
As far as adding power, I have no idea why a non-sequential system with the same turbos should make any more horsepower than a sequential system, all other things being equal. There are sequentials and non-sequentials making 400 whp and I have never seen any evidence that one can make more power than the other. There is a big difference in how the make the power, because the non-sequential setup will have more of a slingshot effect than a sequential setup. Some people like this feeling and its great fun in moderation.


Gordon

All things will never be equal if the huge flapper door is still in the manifold with the sequential setup :) Just look at dyno sheets over the years, it is pretty evident that the NS cars seem to make 10-15rwhp more on the top end. Not many sequential cars ever break the 360rwhp mark, it has been done but is rare. It is pretty normal for a non sequential fd on 15-16psi to break that mark.

Both setups have their pros and cons. I like to convert cars to NS as it makes it much easier when I sell the cars as I know the owners will likely have less problems out of the car down the road, however, nothing beats the feel of a properly running Sequential setup. I have autoxed both and it was a no brainer, the Sequential car was much more fun to drive in that situation. However, on everyday street driving I think the non-seq setup is great also.

dgeesaman Apr 29, 2009 12:04 PM


Originally Posted by gmonsen (Post 9167534)
David... I now understand that there's a few more hp because of the flapper. However, if you completely changed how the sequential system was controlled, couldn't you eliminate the flapper valve and make the two equal? If not, then there's that 10-15 whp potential advantage for the non-sequential. Even given that that is the case, that still doesn't amount to much. Not sure the earlier power hit of the sequentials wouldn't mean that the two would have the same quarter mile times?

Gordon

I suppose you could change it. The Supra has a sequential control system also and it's slightly simpler than the FDs.

Unfortunately it's hard to make any kind of switch/valve/door that doesn't add measureable drag to the flow. Plus, on the exhaust side the doors have to withstand immense heat, which helps explain why they are simple hunks of metal.

What would be interesting is to maintain separate exhaust streams and use the newer adjustable vane turbo design to prespool and/or control the flow. I think it's safe to say that the vaned control design has lower losses than the doors used in the FD's manifold. That could significantly simplify the system, plus allow some nice trickery to keep throttle response sharp. Programming the controllers for it would be an interesting project, to say the least...

staticguitar313 Apr 30, 2009 01:11 AM

In the middle of non-sequential right now, I have a big streetported motor, DP, RB catback, PFC w/Datalogit, IC, and AVC-R, the stock twins have NEVER acted right and I'm tired of chasing gremlins and having the car down. Going non-seq for me is just a temporary thing until I can piece together my single turbo/v-mount setup. I'm going to be doing major porting to the wastegate and the turbo manifold. I'm expecting very little lag. Of course some lag is acceptable trade-off for NEVER DEALING WITH THIS SHIT AGAIN.

The vaned turbo idea is quite neat too

NissanConvert Apr 30, 2009 06:12 PM


Originally Posted by dgeesaman (Post 9167565)
I suppose you could change it. The Supra has a sequential control system also and it's slightly simpler than the FDs.

Unfortunately it's hard to make any kind of switch/valve/door that doesn't add measureable drag to the flow. Plus, on the exhaust side the doors have to withstand immense heat, which helps explain why they are simple hunks of metal.

What would be interesting is to maintain separate exhaust streams and use the newer adjustable vane turbo design to prespool and/or control the flow. I think it's safe to say that the vaned control design has lower losses than the doors used in the FD's manifold. That could significantly simplify the system, plus allow some nice trickery to keep throttle response sharp. Programming the controllers for it would be an interesting project, to say the least...

I don't remember where I saw it, maybe homemade turbo- but a kid has an eclipse with a bodged on holset 35 diesel turbo using a MBC to actuate the vanes. I'd be lying if i said the thought hadn't crossed my mind.

janrx7 May 11, 2009 08:20 AM

My car only dynoed 365whp @ 17psi with non seq turbos. Duty cycle was about 80%, Afr was 11.2 and finished at 10.6. on a dynojet dyno. I was expecting 390whp but turbos are smoking more then a pair of teenagers after sex.


I will replaced the turbos next month and tried to retune to 390Whp. keep you posted.

thewird May 11, 2009 03:19 PM


Originally Posted by janrx7 (Post 9198311)
My car only dynoed 365whp @ 17psi with non seq turbos. Duty cycle was about 80%, Afr was 11.2 and finished at 10.6. on a dynojet dyno. I was expecting 390whp but turbos are smoking more then a pair of teenagers after sex.


I will replaced the turbos next month and tried to retune to 390Whp. keep you posted.

Stock turbo's aren't reliable at 17 PSi and they're just blowing a lot of hot air anyway. Your new turbo's are going to start smoking eventually too running at 17 PSi.

thewird

janrx7 May 11, 2009 03:22 PM

yes true. But to plan 17psi all day. I plan to run 11-12psi on the street and 17psi for some track use.

WaachBack May 11, 2009 03:54 PM


Originally Posted by staticguitar313 (Post 9169698)
In the middle of non-sequential right now, I have a big streetported motor, DP, RB catback, PFC w/Datalogit, IC, and AVC-R, the stock twins have NEVER acted right and I'm tired of chasing gremlins and having the car down. Going non-seq for me is just a temporary thing until I can piece together my single turbo/v-mount setup. I'm going to be doing major porting to the wastegate and the turbo manifold. I'm expecting very little lag. Of course some lag is acceptable trade-off for NEVER DEALING WITH THIS SHIT AGAIN.

The vaned turbo idea is quite neat too

^^ That's how I feel.

G's 3rd Gen May 11, 2009 05:56 PM


Originally Posted by janrx7 (Post 9199338)
yes true. But to plan 17psi all day. I plan to run 11-12psi on the street and 17psi for some track use.

The oil seals fail rapidly once above 14-15 psi. Take a look in my junk drawer! I doubt you will see a gain horsepower. The oils seals will blowby all day long w/out causing a hinderance in output/ power. G

mdpalmer May 11, 2009 09:39 PM

I completely agree
 

Originally Posted by gracer7-rx7 (Post 9166566)
Why would you shoot a 50 shot of nitrous when all you want to do is accelerate into an opening in traffic in the next lane?

You need to think about it not in max power potential but from the perspective of overall drive-ability. From that perspective, it is very nice to have power and torque throughout the rev range. Having 10 PSI at 2500 RPM w/ sequential twins makes for a car that is easy to drive around town and in various real life scenarios. that is one of the reasons people do an LS1 swap - power, torque and overall drive-ability.

If your the kinda guy that lives his life a quarter mile at a time and never sees RPM below 3500, you may be satisfied by something like non-seq. I say that somewhat jokingly as there are plenty of people who only use the FD as a toy car and drive it mostly in off hours or live in a place where there is lots of wide open roads where constantly being up over 3500 PRM is easily accomplished. Some of us that live in more congested areas appreciate low end power and torque and overall drive-ability.

If you have a good setup, you can theoretically make more power Non-Sequential and you'll make it higher in the RPM range compared to Sequential. If you have a good setup, you can make pretty much the same power Sequentially and have more power lower in the rev range.

Sometimes that half second it takes to downshift a few gears and build boost to make the hole in the next lane is too long.

^^ what he said. I know this has been beaten to death... he's absolutely right though. Peak power and "usable" torque are two different things that don't necissarily go together on the same setup. It is much more clear when you plot torque curves together (non-seq VS seq) to get an idea... because torque is really what moves the car and plants you in your seat. Around town I think more down low torque is a good thing :)

PwnedurFace May 12, 2009 01:46 PM

sequential=fun to drive

EjCabrera May 12, 2009 02:24 PM

i have bnr s3 's that i bought non sequential and put on. the power was insane but like realistically i could never make full boost on a normal road or i would already be speeding. on the freeway the power was there but still had the lag. i used to have a evo ix and the spool was way quicker similar to when my stock turbos actually worked. anyways i already converted my turbos back to sequential by bnr and im just waiting for 1 rack solenoid to come in the mail so i can get it hooked up and tuned. i can post up both the dyno's for comparisons soon.


Originally Posted by JDMinard (Post 9167185)
Its not everyone thats has a monster port idling at 2k, lol

Anyway, does anybody want to go full non-seq in a near future in this forum?
So dyno it before/after!!!!!!!!
I want some real proof, ill stick with seq till someone show me a 10hp+ of diff. ( yeah right)

Edit: seriously even with a 3-5hp gain, dont waste your time and money, go single if you really want power


G's 3rd Gen May 12, 2009 02:25 PM


Originally Posted by PwnedurFace (Post 9202134)
sequential=fun to drive

Properly running/tuned FD = fun to drive.

janrx7 May 12, 2009 03:07 PM

Seq= Fun to drive
Non Seq= Feels faster, more violent and less vacuum headaches

I went non seq for reasons
1- Less complex engine bay. looks cleaner
2- Don't have to worry about transition of second turbo
3-Tried to yield better hp results. (got about 15whp)

Regrets no. This can be use as a training ofr when i go single

JDMinard May 13, 2009 10:32 AM


Originally Posted by EjCabrera (Post 9202236)
i have bnr s3 's that i bought non sequential and put on. the power was insane but like realistically i could never make full boost on a normal road or i would already be speeding. on the freeway the power was there but still had the lag. i used to have a evo ix and the spool was way quicker similar to when my stock turbos actually worked. anyways i already converted my turbos back to sequential by bnr and im just waiting for 1 rack solenoid to come in the mail so i can get it hooked up and tuned. i can post up both the dyno's for comparisons soon.

yeh thanks!!! I would like to see that, also like to see both boost pattern/lag vs. RPM's of both setup. How many lbs. of boost will/were you running?

If you can hook us with MAX info you can get, it would be appreciate

Minard

gabe[7] May 13, 2009 12:34 PM

ive been watching this thread and i think that its usable power vs. peak power
think about prosche and how the new 911 turbo has the Variable vane turbos they use those so they can make power throughout the powerband and that power can be used anytime while driving because they virtually have no lag that is the same idea that mazda had when using the sequential setup...the first 911 turbo had horrible lag and was more of an enthusiast's car now i know we are all enthusiasts here but its like comparing a production car made to be driven on public streets and a modified car made to make more power and take track use.

Mr rx-7 tt Feb 24, 2012 02:27 PM


Originally Posted by G's 3rd Gen (Post 8124026)
Anyone who gets aggravated about how much better and more fun (da da da da da) a sequential is to drive over a properly done non set-up needs to come ride w/ me. I have owned and experienced both at all levels of modifications in the past 12 years. Non- done right seems the way to go for pros than cons. If you think non-sequential is laggy it's not set-up right. G

Compare a sequential dyno to a non sequential dyno and there is a HUGE difference, especially after you start modifying.

kensin Feb 25, 2012 03:54 PM

Just down shift ...I swear it works

slowinfastout Feb 25, 2012 08:56 PM

Sequential should be more streetable. If you want big power I would think single would be best since the rotary can spool the big ones fast.


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