Ive read every page of every thread that the 'Search' function found. Im just wondering, since almost every one of those threads was dated 1 or more years ago, how you guys are still liking having your turbos run non-sequentially?

My cars sequential system works fine (just did hose job, think I kinked a hose, easy fix), but I am still curious and interested in going non-sequential. Im not too worried about having a bit more lag, and like the idea of 'preventative maintenence'. Plus having a linear power delivery would be nice.

Anyway, just wondered how you guys that did your non-sequential are liking it still. Thanks.

 

I've had my car switched to non-sequential because of previous problems. I dont like it as much as the sequential system. The quick responce is nice to have imo with the sequentials. For non-sequential, lag wise, it feels like you're running a single turbo.

I've never had a problem since it was swiched over. Nothing has broken down. I get boost the same way, every time.

If I were you, I'd Keep your sequential set up until it breaks.

 

I went full non-seq about 4 years ago and love it, and would never go back.
My last dyno run is in the dyno forum.

Every one I know with a modded non-seq or single turbo would never go back to seq stock turbos.

Non-seq is for a well modded engine not for a stocker.

As I always said,"If you do not like shifting and keeping revs above 3000, and want low end torque; go buy a truck."

 

idk, i heard seq is too complicated

i love non seq, easier on the turbos for daily driving and when you hit boost, its like a one power punch..

i would def go back to seq

 

the only thing that makes the non seq feel like a single is the lag...a nice single pulls the bejesus out of you...non seq is the bastard stepchild...not the singles little brother.

i agree with your later statement...if sequential is working great...dont change a thing..its not worth it.

j

 

I love my full non-seq set up. Doing the full set up takes a bit of the lag away. I also notice I get better fuel milage. I used to get about 200-225 miles out of a tank but now I get 250-265. I also think is easier to drive too. I don't really know how to describe it but I found it easier t drive. Engine bay looks a lot cleaner too, well under the UIM.

*edit- I also ported the manifold and the exhaust entrance a little on the turbo.

 

I like mine on the highway and the strip, but for autocross its kinda laggy.

 

just a question here , say i went with the efini twin turbos that where on the japan rx-7's could i make that seq or is it already? and what is the difference between seq and non...if im not mistaken if your seq isnt that just the tranistion between the first and second turbo and with non seq you dont have that....have searched but still a little confused....

 

I agree with dont change it till you have problems and cant fix the seq. I loved mine in seq there was hardly no lag. Nowing that the boost is there no mater how slow you are going is a good feelng you never know when you will need it.

 

The lag horror stories can be blamed on people who were cheap and wired gates open, or went non-sequential while still having catalytic converters, or both. Properly converted, there is no noticeable lag.

That said, I wouldn't convert a properly working sequential car. Except my own.

 

Well how much would it actually cost for a decent non sequential turbo setup??

 

Uhh, free? You just mod your existing turbos, you don't get new ones.

 

Probably better to go non-seq. while there is no problem. But, what problem? Anyway, clean up the factory mess. Simplify, gasket-match, and port; free up the intake, the exhaust, and turbos. Done properly, you won't regret it.

 

My previous FD was non-seq and I loved the hell out of it. The FD that I have now is sequential and quite honestly, I'm not very happy with it. I do mostly freeway driving and rarely ever get the chance to take the revs north of 5k (where most of non-seq would be beneficial) because of traffic. I say, go non-seq and never look back. LOL!

 

You do know that past ~4,500 rpm, non-sequential is basically the same as sequential, right?

 

The efini twin turbos can either be in the seq. or non seq. setup. The sequential setup has one turbo that spools up in the low rpms and one in the high rpms. This website sells the efini turbos the cheapest. http://www.rx7.com/store/rx7/fdturbo.html

 

Yeah, but there *should* be slightly less restriction due to the flapper/s being taken out right?

Also, if you are going to do the non-seq mod correctly, wouldnt it be a good idea to get a little porting done while you have the turbos out to weld/remove the flapper/s?

 

contrary to what labreck says...there is lag and it is felt....it does take more time for both turbos to spool. period.

if sequential is working then great...if its not...then its a major pain in the *** and most people quit on it and go non seq.

around town...non seq sucks. out on the highway it is a lot of fun....but not even half as fun as a decent single. weeeeeeeeeeeeeeeeeeee.

 

A street-ported engine and a stand-alone changes that, esp. if you aren't doing everything to go single at one time due to whatever constraints.

But, I have to admit that I was given a raging ride in a sequential and ported setup. Unfortunately, all the effort that went into that build seemed cheated of the simplicity, which yields easier diagnosis and better cooling.

This car is at its pinnacle in non-seq. and a single turbo is but a tweak away and that is soon coming.

The I/C is water chilled and was hand-fabbed from a Thunderbird Super Coupe I/C. The intake is interesting and an E6K and battery relocation are two other features.

Damn, my pics won't attach.

 

Have you ever driven a sequential car that made 14-15 psi by 3,200-3,300 rpm?

There may be a small increase in lag when compared to sequential, but it's nothing that would greatly impact drivability and it's barely noticeable when the conversion is done right. I've driven both sequential and non-sequential back to back on the same day, and I've driven three different non-sequential cars converted properly, and if you can find something to complain about, you shouldn't be driving an RX-7. Period.

There are three factors which must be met...

1. Manual transmission only
2. Internal gates should be removed and wastegate enlarged
3. No catalytic converters

I suppose if you lugged the engine at low rpm and were afraid to downshift it might suck. Were you driving around in 4th gear or something?

 

This statement is true with qualification .... above xi rpm in yi gear.

To me, lag is cleanly tested by off-throttle a few secs then wot.

Non-seq at it's best will have more lag below ~3.5k rpm than stock seq. It will have a lot of lag below 3k. That is significant to some, but not to you and many others.

The only 4 turbos I drove that were nearly without lag were a Starion, A4 1.8T, 280Z-t, and my FD. My old 924T had very little lag.

 

Fair enough. Maybe it's my habit of grabbing a lower gear when I want to get somewhere in a hurry. Rolling in third at ~35 mph and grabbing second means instant spooling of the turbos.

Unless I was cruising in 5th on the highway and just stepped down on the gas in the current gear to slowly pass someone, I can't see any situation where I'd be trying to accelerate quickly from low rpm in the current gear. It's not conducive to maximum acceleration even with a sequential setup.

 

Come on guys, it's all logic here. The non-sequential is in no way better, other than simplification, period. Anything you can say about non-seq, I can say the same about sequential, plus I have full boost by 3300 rpm. Other than what I already admitted (simplification), what can non-seq offer that seq doesn't offer, plus more? You say a linear powerband? BS, you get almost no power, until 4200, and BAM, both turbos are full spool and you get a hard kick in the ***. If I drop clutch at 3500, I have a linear power band, full boost, all the way to red line provide linear power, not something that kicks in later. You can't make any more power with non-seq than you can Seq, because no matter what you do, seq does the exact same thing, once both turbos come online. You say that is has to be "properly converted" and you will feel no difference in lag, but now you aren't on a level playing field. If you say you can't have cats with non-seq, then you should compare a sequential system with no cats, and again, the Seq system will rock the no-seq system. Lag will be even less than it was before in the seq system. This is not debatable. A car with a seq system working correctly, racing the exact same car with a non-seq system, will smoke it.

 

Well, that and a well-documented improvement in mid-range power.

How much boost? 10-11 psi? Let me know how you manage 15 psi off the primary turbo in a sequential system, because that's what I'm talking about when I say full boost. 15+ psi.

Bullshit.

I don't think anyone's arguing that non-sequential provides more peak power.

No one removes the catalytic converters on sequential 5-speed cars?

Not true. Non-sequential makes higher boost levels earlier and therefore has more mid-range power than sequential.

Sure it is. In fact, if you said that the sky was blue, I'd argue that it was green just for the hell of it because I don't think you have any idea what you're talking about.

Riiiight... which is why a non-sequential FD was the first into the 10s on a stock motor. Next.

 

Only if it's the full conversion.