I don't want start a sequential vs. non-sequential debate, but I just wanted to offer my recent observations after completing the www.dontbearikki.com conversion.

Simply put, I wish I had done this years ago. Incidentally, I wasn't having any turbos issues other than dangerous spiking at the transition, which is a no-no considering the road & track events that I participate in.

In general it would seem that the typical concerns regarding this modification revolve around (1) boost threshold, (2) boost lag, (3) driveability, and finally (4) noise.

For reference purposes my mods are listed here:

http://www.opentracking.com/ramon_ceron.htm

(1) My boost guage goes from vacuum to boost at 2800 rpms in 3rd gear. At this point I will immediately have 3 lbs of boost. This is MORE THAN SUFFICIENT for everyday driving. I didn't have to change my driving style/pattern as I was always around 2700 rpm when cruising because of my large street ported engine.

(2) Full boost build up (12 lbs) takes about a second and probably arrives around 3400-3600 rpms, but I haven't pinpointed the exact spot because the rush is enormous and my eyes are definitely focused on the road when this occurs. Critical point--if you are purposely racing someone on the street (poor location) or on the track you will find that your shift points are above this area and thus shouldn't present an issue.

(3) I can drive around on local roads and/or highway without all the immediate boost and still have fun. If you are NOT trying to race everyone on the street at every stoplight then driveability is not an issue. I haven't even begun modifying timing with the PFC, which would only improve low end power.

(4) Noise is the only downside for most unless you have a Racing Beat Catback. For some reason my car seems to be real loud when I merely casually run through the gears. The noise isn't bad inside the car (windows closed), but COULD be an issue for those outside (not fully verified yet). Noise under WOP is similar to when I was sequential. Noise when driving at a constant pace (e.g., highway) is basically the same as before.

Some additional comments:
(1) the conversion took less than 2 hrs.
(2) despite all that has been written up (including this thread) I would STRONGLY recommend just trying this set up if you have a full exhaust setup and lightened flywheel. It can be reversed in less than 2 hrs. Everyone's definition of lag and more importantly driving style is different. Experiencing the modification is the best way in making this judgement.
(3) my car is faster now, not because of converting to non-sequential, but because I can NOW safely run a specific boost and hold it to 8000 rpms. My car feels so strong when the boost just builds. SMOOTH is the only term that comes to mind. Anyone who consistently tracks their car should consider this modification.
(4) even lauching my car and accelerating at WOP on the streets is easier and faster as there seems to less power fluctuations and erratic "activity" (subjective feeling) when doing this. I get the same results every damn time--never thought of the value and importance of consistent power delivery before.
(5) driving on the highway isn't an issue in 5th gear as long as you are holding speed of 70+.
(6) although low end power is LESS than sequential it is not weak/low in power. It's just RELATIVELY lower.
(6) remember you are always a single downshift away from an enormous rush of power (big FULL shove in the back as opposed to two strong taps--subjective comment again).

Just another data point for those considering this modification to contemplate.

Ramon

 

Good review, I am also considering going non-seq. thanks



Tony S.

 

I'll be going non-seq once I get my BNR secret weapon twins. But looks like everything will be put on hold pretty soon since the military just surprised me. But oh well. Good write up bro, I can't wait to convert mine!! Laterz.

Zach

 

I'm not sure about this. Anything under 5lbs and my car is a slow fat dog. In sequential, my 1st turbo kicks in @3500rpm and full boost = 4500rpm at which thime the 2nd turbo kicks in and full boost @5500rpm.

If both turbos can acheive full boost @4500rpm running parallel, then I would say non is better.

Are you looking at your gauges right? Maybe have a pasenger look at them for you. It sounds like you are saying you are reaching full boost "sooner" than you would running sequential?

 

Since its dontbearikki mod, and he is always talking up the purple box...does he run non-seq with the purple box? Is that possible (I guess that is my question)? There is a selection for 1 or 2 turbos, but is it a good idea to run non-seq with the purple box? TIA for anyone who can answer...

 

Rikki runs(from my info) runs a stock ecu re-tuned for a Greddy TD-06 and a PMS purple.

The Noise level can be lowered in a non-sequential car by cutting the flapper door out completely. This makes the car a non-sequential from now on car.

 

to each their own.

j

 

Remember if you're "only" getting 5 psi or whatever, you're getting it on BOTH turbos as long as you're below the would be transition point on a sequential car.

 

do you have any dyno results?

 

I don't have a dyno plot of my car, but I'm sure you can find one somewhere on the forum. Again, a dyno plot is just a series of numbers. If you have time one weekend just try it out. If it's not for you then you can undo it rather quickly. I've seen dyno plots before and based on what I know now they don't tell the whole story--lot of this is based on driving style as well.

 

Hmmm...I'll have to see what kind of boost pattern the JDM Type RS/RZ twins give me?

I didn't you had a large street port from Dave. Mine's a mild street port...15% enlarged primary intake and exhaust ports, 25% enlarged secondary intake ports.

 

Ramon,
I'm glad to hear the conversion went well. The biggest thing I liked about non seq was the smoothness on the road course. Hmmm, now that i think about it, that is the only thing I liked about non seq
From looking at dyno charts and comparing seq with non seq, the non seq setup always seemed to have more area under the curve and always looked better on paper.

 

When you do the full non seq conversion, you'll love it even more. The best mod I've ever done to my car. IMO. CJ

 

My question didn't get answered!

 

GoRacer, I guess I didn't answer your question because I didn't quite understand it. You mentioned that you get full boost (e.g., 12 lbs) on your 1st turbo by 3500 rpms. That's perplexing as you should get at least 10 lbs by 2700-2800 rpms in say 3rd gear for example. Also just before the transition (i.e., 4500 rpms) you might see a little dip in boost, but then it should hit full boost IMMEDIATELY with the second turbo coming online--in fact it will probably spike (hence my problem). Unless I understand you wrong, which is very possible, I'd say there is something wrong with your control mechanism.

 

has anyone had much success installing the seq/non-seq switch set up? i know it's floating around here somewhere

I don't like the non-seq all the time because of the noise (dp, mp, Greddy SP is pretty loud as it is) and the low end lag, but it would be nice to just switch it on when i wanted to eliminated the transition and have some fun.

 

Manny:

I too am curious about your new 99 spec turbos in the sense that I wonder if you will be able to control boost spikes. Although I recall you have a high flow cat which will probably help a lot.

Josh:

From what I recall (maybe a thing of the past) you were "racing" 100% of the time Basically I just like things to be simple and reliable--remember my boost problems at VIR last year? No more of that crap.

Meanwhile let me know if you sent the check in for Spring MADS http://www.mazdadrivers.com


R

 

Boost "starts" @3500rpm and "not" full boost, it begins there and full boost on 1st turbo is @4500 when the transition begins, then full boost for the 2nd and/or both is @5500rpms.

This should be normal, not a problem with my control system. Is this not normal for every one elses RX-7?

How are you getting "and you other guys" claiming the same thing running parallel = instant full boost? If boost kicks in @3500 then you can not instantly have full boost @3500. You would have to be starting boost @2500rpms.

M2 claims parallel boost would only "begin" @4500rpms, the same as the 2nd turbo jumping in with transition in sequential mode.

 

GoRacer- I start seeing boost ~2000 and 10psi ~2500rpm. Unlike rceron I spike on primary boost, and secondary is 8psi at changeover climbinig quickly back to an even 10psi all the way to redline. I think you should be getting boost much before 3500.

 

There is something wrong with your FD In a sequential FD, 10 psi should be seen at 2500 rpms - non-seq. (depending on full conversion or not) 10 psi sould be around 3500.

Non-seq definitely has it's advantages - but it's not for me. i just switched back to sequential

 

WHAT!? You are saying your stock twins spool up @2500rpm and M2 ball bearings take longer to spool @2800rpm? ...ok, some reply with the real facts cause I don't beleive this.

 

U may want to check with KwikRX7 since he had non -seq on the BNR and they were a bit sluggish like a single....... he jumped back to sequential.........

 

oops....... didn't see the response by Kwikrx7.....

 

I just got home from driving around. I have non-seq in 3rd gear I get full boost (10-11psi) at 4500 rpms. For the record: I have an intake, street port, DP, HiFlo and TRUE non-seq - w/stock CB.

I'm pretty sure everything (that is pertinent) is working well in my car.