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-   -   Turbos are coming out...go non-seq? (https://www.rx7club.com/3rd-gen-archives-73/turbos-coming-out-go-non-seq-24985/)

Hyperite 10-09-01 03:30 PM

Turbos are coming out...go non-seq?
 
Okay, as mose of you know, i'm pulling my turbos to port the wastegate. Reading up on some sites has gotten me thinking about going nonsequential. What do you guys think? My mods are:
PFS Downpipe, Midpipe, Catback, Intercooler
Profec B
Pettit Intake
Remapped ECU (I'm planning to get the PFC in the spring)

If you guys tell me to, I will :) But where can i get all the blockoff plates i need? I guess, what is the additional cost to do this.

Thanks!
~Tom

Bacon 10-09-01 04:07 PM

u only need 1 block off plate, the one that covers the airbypass valve, wich u can fab yourself, or go to a local machine/cnc shop and pay a bit but have it look nicer..

i loved my non-seq, but if u have a good workin seq i really wouldnt trade it,. i mean u can wire the nin seq, or do it through the pfc...i just liked the powerd band alot more, no guessin, no chance of something poping off...its alot cleaner under the manifold 2

Brad 10-09-01 04:42 PM

I'm in the same boat as you man...turbos are coming off and I'm thinking about non-seq. My question is do you have to have lots o mods to do this?? I only have CB and DP. I know it would be kinda laggy, but it wouldnt hurt anything would it??

Hyperite 10-09-01 09:00 PM

No, it won't HURT anything, it'll make it a little more reliable. But someone told me, the more mods you have, the more you should go Non-seq, so....idunno. I'm still having a huge problem getting the LAST bolt off the turbos. been working on it for like 2 days.

~Tom

Merciless 10-09-01 10:55 PM

single :fruit:

Hyperite 10-10-01 01:32 AM

yeah yeah....someday, when i have a few bucks. Hey, if anybody has ideas on how to get my last pain in the ass nut off the stud, lemme know. It's really rounded, and i can't get a wrench in there since it's recessed.
~Tom

mmaragos 10-10-01 10:54 AM

For those of you considering the nonsequential mod, check out this:

http://www.scuderiaciriani.com/rx7/non-sequential.html

Diehards have likely already seen this or know this, but there is a lot there that I never thought about.

Hyperite...sorry, no good ideas, how about some bad ones? Not too sure what the size of the nuts are...maybe you can use a slightly smaller English socket and force it on? I have never used one of those variable sockets (with all of the pins in them - I think Sears (Craftsman) has them), so I don't know how good they are or if they will hold up or if it will even fit to reach the nut. Commericals make them look like they will grab anything (rounded off nuts, etc).

Hyperite 10-10-01 10:57 AM

It's a 14mm nut, can't get a std set on there well, since it's even bigger than metric at that size. I JBwelded a 14mm socket on there, but guess what, after a day of curing, it still just cracked right off. I guess i'll probably have to just sit down there with a
grinder for a while and saw the fucker off. I talked to sears guys about both metwrench and that thing with the pins....they disavowed any knowledge of them (they knew what they were, but wouldn't tell me if they ever sold them or where i could get them now).
~Tom

1RedR1and1RedPEP 10-10-01 11:02 AM

I did the non- seq. mod early this summer and wouldnt go back if i could, wait a minute, i could and i still wouldnt.
It has proven to be trouble free and the performance is great.
There is a bit of low end that is lost but ill happily do without it. This car sees mostly track duty so the low end loss isnt really a concern.
With the non seq. mod i do recomend going with a straight thru exhaust and RRFPR to go with it. I have stock injectors run by a M2 S3 ECU and it runs very well.
Good luck
1R1

rx7tturbo 10-10-01 12:51 PM

From the Scuderiaciriani.com, read this...see if it's worth it. Read the paragraph in red. Boost control is the key!!!!

You can convert to non-seq without taking the turbo off by simply disconnecting 95% of the control system and wiring the precontrol stuff fully open or closed (ie. deactivate everything but primary wastegate.

This gives you 95% of the non-seq total mod but still let you go back to seq with no sweat. Lets you get a feel for how it works and responds and if you do not like it you can go back to stock. main advantange for most of us of non-seq is simple operation and reliability - plus drasticly reduced cracking of the exhaust side turbo houseing due to constant heat cycling of of seq control. Turbo control becomes 1000% simpler to troubleshoot to the level that even I, after lots of study etc can do it myself. There are only a few shop in the us that really understand the seq system and can keep it working right. If you do not live near one of them then you have some tough choices to make.

If your seq system is working OK now, leave it alone till you have trouble.

Disadvantage is you need to dump the CATs to make it work well (you need the higher flow to reduce lag plus an open intake), its makes the car louder and instant 10-12 psi boost at 3000rpm is history - boost build slower (not really lag) and its about 4000 or more when its full bore. For no-brainer street performance the seq is hands down better.

I ran 2.5 yrs with the kluged up non-seq with no problems. When you permanately mod it to nonseq by physically removing and machineing/welding out the seq stuff you improve turbo eff so much that just about everyone who does this has boost control problems (ie. at 6000rpm and up you cannot keep boost under 14psi because you have exceeded what the wastegate with all reasonable mods & enlargements can handle.

Hyperite 10-10-01 02:26 PM

Yeah, but isn't that w/o a ported wastegate? I'm porting mine, which is the whole reason i'm exploring this.

rx7tturbo 10-11-01 10:51 AM

I believe that's the case even with ported wastegate.

Ask the people who have done it already...get them to honestly tell you if they have boost spike in higher PSI.

Scorpio 10-11-01 08:01 PM

You won't have any boost spikes with non-seq, but you may have boost creep (wastegate is wide open, yet boost is still slowly climbing past what you wanted).

You can solve this problem by adding back in a little restriction into the exhaust path...either a more restrictive cat-back or a hi-flow cat instead of a mid-pipe.

I swapped my hi-flow cat back in and the boost creep was gone (and I have a Trev ported wastegate).

I have some info on my projects page at:
http://www.micromanx.com/goble/rx7/projects.html

Hope this info helps...

KZ1 10-12-01 07:40 AM

For the record going non-seq is a performance dowon-grade. It reduces performance by many respects. However, it is much better than having sequentials that don't work properly. So, if you can't figure out your turbo problem or do not have a competant mechanic, going non-seq can be beneficial. but not comapred to propely running seq' system.

Also, from all this latest talk about these m2, etc ball b earing hi-flo twin setups, it seems as if they are a more expensive but better alternative to a singel too. Personally I love the sequential setup.

I thought about going non-seq after trying to fix my seq' setup for 5 months, but since I have it working now I woudl never do it.

Scorpio 10-12-01 11:55 AM

My non-seq mid-range tq and hp is better than most people's seq mid-range tq and hp (for similar boost levels) -- and I consider that a *huge* performance upgrade.

Making a blanket statement that non-seq is a "performance downgrade" is just plain wrong (or, just an opinion, which is fine :). For the record, it increases performance by many respects.

If you want to talk about low-end, then sure, you lose some low end--that's a specific area where non-seq perrformance is downgraded. If you want to talk about reliability and/or power-smoothness, then non-seq is a huge gain (ditto for mid-range), performance is definitely upgraded in those areas.

I'm not saying non-seq is better or worse than stock-seq...I'm just saying both have their advantages and disadvantages...and each person should decide is better suited to their likes and dislikes for their 7.

My statement has always been that non-seq is not for everybody and if you are thinking about it, try to drive a car (or in a car) that is non-seq and see what you think. After I did that, there was no question that I wanted it...and I've been much happier ever since. Different strokes for different folks.

kwikrx7 10-12-01 11:38 PM

When I went non-sequential I put on a midpipe and my car was extremely laggy - I didn't go WOT since it was a new engine so I don't know if I would have had creep or not - I do know that non-sequential made it much louder and laggy with a midpipe. If you have your turbos clipped it helps them spool faster. I swapped my mp with a hi-flo and it works 100% better - quieter, much more low-end pull-hardly any lag - I have full boost (13psi) by 3500-3800 rpms and with non-sequentials it pulls like a freight train all the way. This in no way is a performance downgrade. In the powerband you have atleast 20-25 more hp and more torque from 4K to 6K rpms over the seq-setup. I loved the seq feel down low but with the right mods you won't notice it much. Much more reliable, a little better cooling for the engine bay (a lot comes out) and more power where you need it. If your seq is working then leave it till you have problems. The stock setup is enjoyable. The more mods you have, the more the non-seq will benefit you.

TracyRX7 05-18-04 10:18 AM

If you have room around that last bolt try grinding 2 flat faces on it with a dremmel and locking on a big set of vice grips or if you want to try and be really good on the dremmel try to grind the sides down to a 12-13mm.

The seq/non-seq debate really comes down to the use of the car. If you're going to track the car and you heel/toe well then the non-seq should work well for you. If you're going to autocross or street drive you're probably better off staying sequential.

Montego 06-09-04 12:02 PM


Originally posted by TracyRX7
If you have room around that last bolt try grinding 2 flat faces on it with a dremmel and locking on a big set of vice grips or if you want to try and be really good on the dremmel try to grind the sides down to a 12-13mm.

^^ I think he most likely removed the bolt by now since it's only been 3 years. lol :D


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