thats what my idea came out in my head but typed out the wrong way, sorry. with the exception of "at transition you have to spool up one large turbo. It may be slightly prespooled, in a manner similar to the way the 2nd turbo is right now, but I guarantee that the delay will increase." i meant somehow have the secondary prespooled just enough where its at 0psi, you know not at vacuum but not in boost either, thats how i raced my old 02 jetta on the highway...get the boost needle to read 0 and then on the third beep, puch it!.....the 3rd gear pulling this 4-door with 340hp and 318lb-ft up to 160mph.....that was somethin else...it spun a bit in 3rd too i love that thing, it was one of my DD's

 

^denial! You just don't buy an RX-7 cause you want reliability. :p Just messing but yeah turbo lag is the ghey sequential for life!

 

Ok I just got my car back yesterday...

Full sequential. There are some definite pro's and some cons.

Cons:
I have all the mods that people state about minimal lag. CAI, SMIC (PFS) DP,MD,magnaflow exhaust, I have a streetport too. Full boost by 3800 RPMS...yeah it's laggy. . People who get full boost by 2900 KUDOS! It's not the case with me. Ond oh yeah the car is louder.

Pro's:
Oh man the boost is just so predictable!, no weird *** spike at transition. The boost seems more constant/safer. I widened my twin turbo powerband by 700rpms. of course much simple system to diagnose


Overall: I don't regret it. IMO the pros outweigh the cons. But it would had been great to have my cake and eat it too.

 

^^ how bout some video...i always want to see fds in videos!!!

 

Yes, if boost is not raised past a certain point. I believe 12psi w/stock fuel??? Not sure.

 

Of course. Just limit boost to 10 psi. If you actually remove solenoids, you will have to properly deal with that -- resistors where necessary.

 

I miss my sequential.. 14psi at 1900rpms = amazing.

I'm sure I won't make full boost till like 3800rpms now.. yay =/.

 

Low brain power = non sequential. Part of what made the rx7 such great sports car was the sequential turbo system. Now having said that, IMO, a sigle turbo is the way to go for drag racing purposes only. As far as best performance when driving in the mountains, it is hard to beat the twin seq.

Just a thought and for those that can;t troubleshoot the twin sequential then single setup is a must. I know I've had my issues with the seq. and they are hard to troubleshoot.

 

^^ apparently you didn't read one single sentence of why I went non-seq.

so again:

I did it to get consistent, predictable boost and to simplify my system. My sequential boost used to be very stable that is until I started modifying my ride.

 

A lot of people forget to make the distinction between turbo lag (how long it takes to build boost when you apply accelerator) and boost threshold (RPM when min or max boost is made... one should qualify if the min boost or max boost is in question). While the max booost threshold is a lot higher--say 2000 RPM or so--on a non-sequential (or single for that matter) setup, there is pretty much zero "lag" past the upper threshold.

My car is full non sequential. I dunno about you guys, but past about 3500 RPM, when my right foot goes down the car has pretty much instantaneous boost (I get about 12 psi or so... spikes to 14 sometimes ) and hauls *** as a result If you're tooling around town, sure it's laggy.

 

both setups drive basically the same when you are driving it hard after the transition, so if all you do is drive hard (weekend car), what do you get from staying sequential other than a more complicated system?

why do people with hicas (4 wheel steering) nissans remove the rear wheel steering? because it doesn't make the car faster and just adds another failure point. same thing with the sequential control system.

and if you are well modded, you can spool both turbos before 4500rpm anyway, so why wait till then?

 

is only the reduction of back pressure what will allow a turbo to spool sooner?

 

basically. combined with a better flowing intake for more gains, and an IC with less pressure drop for more still. the more you mod, the sooner you're turbo's will want to spool generally.

it's no problem at all to get an instant 5 psi in the 2800-3k rpm range for me with the stock ic and main cat, and non ported seq components on the highway. and that's plenty for passing. you have to remember that it's not psi that moves the car though, it's flow. so even with 5 psi in non seq, that's 5 psi coming from 2 turbo's, and generating much less heat and backpressure than 10 psi coming from one. so it's not as if you are losing all of your low end turbo power by not getting as much boost.

 

Come on, no one has a response to this post?
This is clearly the best question / point made in this thread

 

^^^^
There's just so much to say that we don't know where to begin

As for the sequential vs. non-sequential debate, I really don't understand how people say that sequential is soooo unpredictable???? Everyone who owns an RX-7 knows when the second turbo kicks in. It's more a matter of "are you paying attention" when driving hard? It's all relative to what a person wants, but I can tell you this, I'd take a working sequential system over anything else any day. When I bought my car, the damn thing wouldn't even boost on the first turbo due to a clogged DP. Since then, I have been through the whole system, replaced every hose with silicone, and replaced every single solenoid....eliminated the emissions crap, and have not had one problem with my system in 3 years.

What's the point??: Do it right, Do it once. Bottome Line

Joe

 

If you want to buy me a 3-bar sensor and pay for Steve Kan to come back out, I'll run 17-18 psi on 100 octane and go for 400 rwhp.....

 

Exactly... whats the point?? Do it right, do it again three years later... Or just simplify and not worry about it. I chose the latter and increased my wot powerband.

 

3 years and no problems for me.


Who drives around at WOT?

 

A lot of people do - in their head.

Moving power up the rpm band is fine for a race car, but makes very little sense for a street driven car. I would love to know where the public roads are in the US where I can do three or four 6k+ rpm shifts in a row more than a few times a month.

The simplification argument makes no sense to me. Any time functionality is removed from a car, it is simplified somewhat - but this is a side-effect, not a goal.

These cars require attention on many fronts, and a few extra hours over a weekend replacing hoses and doing some solenoid and actuator checks is hardly a huge deal.

I guess waiting an extra 2k rpm for power because I have a fetish for removing three or four solenoids and a dozen or so three-inch hoses is a tradeoff I don't understand. In any case, someone who is capable of doing the non-sequential conversion themselves should have no trouble debugging a sequential system.

 

Well ok then, it largely depends on milage. Are we that dull? Do I have to connect the dots?

I WOT my car every time I take that bitch out. That is the only reason why I own it. My truck and my 71 VW ghia are for cruising around town.

 

I know, I was just making the point that if you go through the system properly the first time, then there should be no question to whether it should work.

 

The system was done properly when it came from the factory, and yet here we are lol. As far as when I did it, it was done properly and it worked fine. But there's that damn heat issue. Hoses get brittle, solenoids take a dump. It's just nature of things. With me after three years of use, I would have to go back and trouble shoot a problem every 3-4 months. I'm sure that you know that it's fun as hell to play let's find the cracked hose game. Another option was to redo my system all over again, but that was sooo much fun the first time that I felt I didn't deserve to have so much joy in my life lol. So I gave non-seq a chance, I wanted to see what the big debate was for myself. Verdict is that I like it but still I would not recommend it because it's all about preferences, and mods so basically it's up to the individual to make that judgemnt for themselves. But to say that non seq = low brain power is just an ignorant thing to say. As the only reason people go non-seq is because they can't figure out a problem.

Guys don't get me wrong. A properly working sequential system is great. Don't forget that I had a properly working one just a couple of weeks ago (then a solenoid took a dump), so the comparison is still fresh in my mind. For my purposes and experience (with my set up) non-seq was the way to go.