jpandes

I have read in this thread that running Seq twins with >340rwhp is hard to control during the transition. Is this true?

The reason why I ask is because I am having my motor installed and C2 Automotive is going to return my car to Seq from Non-Seq.(and charge me for doing the vac. hose job) I will have a streetported motor w/ all the BPU's(ie. IC, CAI, HF CAT, CB, DP, HKS TP, 1300cc inj's & Power FC)

So, should I even bother paying them to convert my car back to Seq and do the hose job?

93BlackFD

no, get the full non seq and a MID PIPE

mmonaco

Ya if you have a full exhaust and are thinking of going single than go non seq and see if you like slow building boost! The slower building the better IMO!!

Mahjik

iTrader: (1)

Well, I don't know if that is completely accurate. I know a few people who have put down around 360rwhp on the stock sequential twin setup, as well as kwikrx7 who dyno'd close to 400rwhp on the BNR Stage 2 sequential turbos.

The full non-seq conversion allows a little better flow (which equals a little more power) since the flaps and actuators are removed which is why you see higher hp numbers than the sequential setup.

AbadR1

iTrader: (1)

Cool I did not know that, hehe learn something everday. I just know if your running non boost kicks in around 3500rpm, but do not quote me on that. Running seq causes problem after 350rwhp. Because it is hard to get traction. Because boost would kick in so quick around 2500rpm. Plus secondary does not kick in til 4500rpm. Anyway Iam definitely thinking about running non. Since if you race, you would never go down to below 3500rpm anyway.

Mahjik

iTrader: (1)

You should take a look at some dyno plots first.

If you get some upgraded turbos, then they can/will spool faster than the stock ones which would make the difference between sequential and non-sequential not much of a difference. However, on the stock twin turbos, there will definitely be a difference.

911GT2

I say go non-seq all the way. Especially if you plan on going single, because the lag difference over the stock seq system would seem like a lot, but there should be little to no difference in lag between the non-seq and a single.

My theory is that there is so much involved in the seq system, that something is bound to break. My car is a daily driver, so I need it to work, every time I hit the gas, it needs to go, no questions asked. With 150 or so feet of hose, and god knows how many solenoids, something is gonna break. Even if you pay a shop, or take the time youself to go solenoid by solenoid, hose by hose, and make it work properly, everything is still 10 years old, and sometime soon, something else will go.

Sure seq is awesome when it works(supposedly, I've never felt it). But to me, it just isn't practical, and as you say, if you're actually racing, be it drag strip, track, or just smoking that ricer in the civic, it'll never be below 3500 rpm, so why bother?

jpandes

Thanks for the comments guys.

My car is already Non-seq.(13-14psi). I started this thread to try and figure out if I can save some $$$ on labor by having the shop not spend the time on doing the Vac hose job.

I'd love to have my car run sequentially again. I just don't trust that my mechanic or I, will be able to get my car to run a perfect 14-12-14 psi boost pattern. All those solenoids & check valves will still need to be working perfectly...

And, if there are even more inherent problems with the Seq. system while running more rwhp and boost, I'd rather just leave it as is: Non-seq. Rikki-style running 13-14psi. I guess that's what I'll do.

Mahjik

iTrader: (1)

What's the percentage you are racing ricers or have your car on the track verses driving through the city?

Honestly, I don't think there is any real hard data about it. It's just easier/cheaper to get more boost by going full non-seq which is why some people choose to to it. Since kwikrx7 is about the only one on the forum with BNR Stage 2's sequential, he's about the only guide we have. If I remember right, he wasn't boosting them very high when he made his dyno run (which was almost 400rwhp).

I guess it really depends on what you are looking for out of your car. Me? My car will be sequential for as long as I own it.

racer rx

There are a couple buddies here that run non-seq. as well. But they have had selenoid or boost troubles... to make their turbos run they had to go to non-seq. It was too hard to find where the problem was.

Myself I still have a perfectly (knocking on wood) working sequential system. And it feels great... and fun when the secondary comes on board. We have 3 3rd gens here that plan to drag race at the strip this year...
I guess I will see what their non-seq MPH is at the track to make me switch my perfectly running seq system over.

kwikrx7

If you already have the turbos out of the car, but the TCA/flapper door out if you go non-seq, it will help with flow as earlier stated. If you plan on racing or doing track time - go non-seq. If you look at non-seq vs. seq plots you'll see that non-seq will usually pull past the sequentials by 3500 rpms and make a little more power up top. There are less problems and less to worry about if running non-seq.

But the key is - IF IT IS STILL WORKING PERFECTLY - why mess with it. I am more of a V8/torque/low end power guy that when I hit the gas from any rpms it's going to pull. I don't need to have 10 second slips, I just like to go through the gears on back roads - this is definitely more fun in a seq. FD - I haven't had a problems since converting BACK to seq in March. Controlling boost is tough with a midpipe and sequential but I have a HF cat and have no problems - I even use the PFC to control boost. It usually comes down to how well the car is tuned also.

artguy

I push 381rwhp and 312lbs of torque and I dont have any issues with control...just need good rubber.

non seq is for the most part too laggy for me personally...i prefer throttle response and as minimal amount of lag as possible.

good luck


jason

ttb

little factoid - fd is first mass produced car with twin sequential turbo system :-D

rx7machine

Good to know..

homie

Just curious....how much power have you guys seen out of a non-sequential twin set up for the FD?

Mahjik

iTrader: (1)

Stock twin turbos:

https://www.rx7club.com/forum/showth...hreadid=152271

https://www.rx7club.com/forum/showth...hreadid=152260

Still waiting on some of the BNR upgraded turbo guys to get their cars dyno'd:

https://www.rx7club.com/forum/showth...hreadid=150528


M2 upgraded turbos (sequential though):
https://www.rx7club.com/forum/showth...hreadid=172977

homie

Thanks Mahjik !!!!!

fitzrx7

iTrader: (1)

I run 12-11-12psi every day on my stock turbo sequential car that makes 350 RWHP.

To answer your question it isnt hard to control at the trasition if you have good tires on the car and know how to drive. I would assume 245s on the stock rims would work with good rubber but I have 255s on 9" wide rims.

This works great and the best part is the boost comes on smooth from a stop, no need to do 3k clutch drops just to get the car moving from the line, just hit the gas and go.

If you are lazy or just cant find a competant person to work on the car then go ahead and keep the non-sequential, but if you want better drivability then keep the sequential.

If you have a Datalogit and the PowerFC then you can make the car run in non-sequential mode by simply changing the turbo transition RPMS to below you idle RPM.

Jon
'93 SSM base
350 RWHP on stock turbos