MaczPayne

iTrader: (5)

Getting them to run sequentially is not as easy as you think. Have you taken a look at the FD factory service manual?

Going back to TitaniumTT's post,

"...unless you plan on spending thousands of dollars to run them sequentially"

slo

iTrader: (1)

You can get the FD twins to run sequentially with 2 manual boost controllers (or one electronic for the actual boost control and one manual for the turbo pre control) , 3, 3 way vacuum solenoids, 2 RPM switches and and a 5 wire NC/NO relay, about 10' of vacuum hose 3 check valves and a vacuum and boost chamber.

I guess that is kinda complex, but if you already have the REW engine complete you can easily get it to work off a haltech E8 or E11, claudio got one to work off a Haltech E6k. Or even easier cheaper you could use a PFC.

Howard Coleman

iTrader: (6)

post number one...

"i need some ideas on how to make a manifold for a twin set up"



over 10,000 miles to date. lag? i make 200 rwhp at 4100 rpm, compare that to your typical GT42 dyno sheet. 364 ft pounds tq at 15.5 PSI. hp target is 630 at less than 25 psi boost. two 3 inch downpipes. internal wastegates. pump gas and alcohol only. no racegas. love the twins. FD

daily driver.

hc

FrankV702

iTrader: (14)

DAMN!! You've got some money put into that setup! Any pics of the manifold?



If you use a spacer for the FD twins on an FC, you won't have enough room for the DP to be efficient. I've tried it, and had VERY LITTLE space to work with for a DP. I dumped that in a hurry after seeing that and went back with the stocker for a while 'till I got my bigger single.

If you really want a twin turbo setup on your FC, buy one that's premade already for the application. If your going to spend the money on making one.. Use better turbos. I always thought about trying out two GT28s or similar. At least the flanges are somewhat more common then the stock s4 turbo flanges which would need to be custom made...

JSmith0101

iTrader: (6)

I have seen this FD on person, it is truly amazing.

And it's very clean, also.

Eight more months til I get to see it again.

arghx

iTrader: (3)

running FD twins would be completely retarded. What a waste. If you're going to twin turbo an FC, make it all custom (non sequential) just so you can say you did it.

slo

iTrader: (1)

Not if you swapped in a 13b-rew and want a fully smog legal car.

Wezzmo

this is a mates set-up which I am hoping to buy off him very soon, as he is going to a single...

the turbos are s5 with 12at exhaust housings..

dyno:


330 on only 12 psi is pretty respectable

RETed

On DD dyno too!
On a DynoJet, that should be 350 at the wheels...
Nice numbers, but...

A hybrid will hit that number easily with a LOT less work...


-Ted

MaczPayne

iTrader: (5)

And the truth shall set you free.

TitaniumTT

Are you joking? You must be joking. If you're not joking you should just slowly walk away from the thread becuase you have absolutely no clue what you are talking about. Seriously - no more talking about twin turbo's for you.

Just as proof though - FD twins run sequentially have MORE lag and LESS power than most singles. FD twins sequentially will have LESS lag and only slightly LESS power than the "rich mans non-sequential." FD twins sequentially will also make MORE power than the twin S5 setup shown above and I would venture to say have better response.

TitaniumTT

Which was more involved than I wanted to go. I also was dead set on using Rob's solenoids but the MAIN thing is I wanted 1 control unit for the whole thing & I just didn't have the faith in a PFC with a butchered frankensteien harness and a few other things that I was unsure of. There are two ways that I would do it..... My way (Motec) or YOUR way - 13B-REW swap with a PFC.

arghx

iTrader: (3)

if you are going through all the trouble to twin turbo an FC, why use turbos that small? and the HT12 is way smaller than an HT18. Have you ever compared them physically?

I'm not saying they're horrible (although a pain in the *** the keep running properly in sequential form), but they are only good for 330-350rwhp on most FD's. too much trouble for too little power in an FC. And yes I know how responsive they are. I've plenty of time helping my friend with his sequential FD. But I also know how annoying the boost drop is in transition when you crank up the boost.

TitaniumTT

Becuase all I'm looking for in terms of power is 350-375 RWHP. My MAIN focus is response.

They're good for more than 350RWHP not to mention there is always the BNR upgrade which is good for even more. As for the transition, yes it does kinda suck when the boost cranks up but I'm convinced it can be worked out with a shitton of dyno time and the proper hardware. Mazda got the transition VERY smooth..... why can't it be done again? The RPM range may need to be brought down and the transition boost may need to be on 8-10... maybe 12 PSI before letting it sign at 14+ but I'm confident that it can be made smoother than most are now

I have compared the two interms of size and it does seem logical that the two HT18's would make more power but they don't. I'm not going to argue with dyno results even inf there are FAR fewer on a twin HT18 setup. I would imagine it has something to do with the exhaust restrictions.

Havoc

Wezz I didnt know you where buying this For the FC Im assuming

Personally I like worm burners setup

http://members.westnet.com.au/helpme.../rx7/17jan.jpg

-Anth

arghx

iTrader: (3)

Because Mazda designed a system that works for lower boost. Look through the Power FC forums for example and you will see that nobody seems to have figured out how to avoid a significant drop in power and boost at transition when you crank the turbos up. I'm not saying it can't be done, but the knowledgeable people who have tried it have found significant limitations. Personally, I helped my friend with his sequential FD and the best we could get it with messing with the Power FC (stock solenoids and everything) was 14-10-14. It makes me wonder if the 99 spec sequential system, which is supposedly controlled in a different way, would be better at it.

Wezzmo

yep, hopefully anyways, always loved the look of the twins on jimslicks car, and my fc is in definate need of some more power!.

I really should be spending money on my FD... but you get that...lol

TitaniumTT

I feel that the Power FC is limited in the way that it controls the sequential system. You have more hands on experience than I do but through my research I didn't feel that the PFC would allow me the control that I felt we needed to get the transition smooth. With the PFC can you contol all 5 solenoids independantly?

My plan to the control of the twins involves a Motec M820, Rob Bailey Industrial Solenoids and 3 pressure inputs and 5 seperate solenoid outputs. Monitoring MAP, secondary turbo pressure, and exhaust manifold back pressure I feel confident that with independant control of the 5 seperate solenoids and programming that says when the exhaust manifold pressure is this, or the MAP = that, start to open the prespool, correlate the 2ndary turbo pressure with the MAP and control the charge control and charge relief based on the difference between the two..... I think it will work. I have yet to start building said map but I've spoken to a few people in the industry that are highly regarded and they see no reason why it can't be done. And these are people that make thier living working for professionals that need **** done regardless of how impossible it may be.

slo

iTrader: (1)

Wrong, I have driven one power FC car running 16PSI the transition lost 2PSI only in first and less in the higher gears, many others have gotten great results with the PFC, the real problem is controlling the pre-spool everything else is just a digital ON/OFF switch, the pre spool is the key to all.

slo

iTrader: (1)

TitaniumTT, your car will be a blast to drive and fast, but for the kind of money your spending you could have twin GT28Rs with the right specs running parallel you could have 15+ psi by like 2500rpm and thats off turbos with the overhead to support way over 450 WHP on race gas and at least 400 on pump.

here is a link to a post by a member with larger parallel twins than even a GT28r

https://www.rx7club.com/showpost.php...1&postcount=54

He is seeing 20PSI by 3500 rpm.

What this translates to is better or equal low end power, even probably extreme low end that stock or BNR sequentials, and much better power from about 3500 on with a hell of a lot more overhead for less or equal money, and no possible boost transition issues.

Oh and a much simpler system where brand new turbo's are still available off the shelf for about 600 dollars each.

I would go parallel twin with GT28Rs (maybe larger) if not for my issues with smog legality, my car is legal (well as far as they can tell for the first time ever).

Hell with an FC you could do dual 3 in downpipes and dual 3 inch exhausts for a true dual turbo setup, and use even smaller turbo's (GT25s) meet your power goal and have boost even lower.

You gotta figure mazda themselves wouldn't have messed with the sequential turbo system if they didn't have to push through cat converters and overly quiet exhaust systems.

TitaniumTT

Thanks - for all the time it better be a blast When I was doing alot of this research and deciding on how to take this project (literally 2 years ago at this point is when I bought the 13B-RE and the twins shortly after.... jeez that's along time) I really didn't find any info on parallel twins nor did I really have enough faith in my fab skills to build a proper manifold. The sequential thing was also a 9 or 10 year old dream after driving an FD and getting out with a hardon proclaiming, "THOSE TURBO'S WILL BE ION MY CAR ONE DAY!" I was also really concerened about response and there wasn't a whole lot of info - that I could find anyway - on parellels and their response. It was also a preconvieved notion of mine that they would be laggy and that was one of, if the not the biggest concern of mine.

The good news is the big money that would've been spent (ECU) is already spent and if I decide to go down that parallel road in the future, as opposed to the BNR's - it would certainly be cheaper as the Stg 3's are $2400. If the turbo's are $600 each, I could probably put the rest of the system together for under $1200 and I'm getting a little more confident in my Stainless welding ability which would of course be key. I think at that point the only concern becomes exhaust noise. Hopefully by then the car will be smog exempt, something I'm not looking forward to in a month or so as the emmission ****'s of CT (I know - not nearly as bad as CA) refused to renew my reg until I passed - *******. Looks like I'll be doing my tuning on an engine or trailering the car to the dyno.

Definately something to think about in the future though.... I'm intrigued now thanks

arghx

iTrader: (3)

well then either I'm not looking in the right places or everyone seems to be hush-hush about this stuff. Was this car using restrictor pills? Stock boost control and precontrol solenoids or aftermarket? The Power FC really doesn't give you much control over specific aspects of the sequential system from what I can see. You set a precontrol boost level and duty cycle (the "secondary turbo" boost setting in the datalogit?) which doesn't seem to have a whole lot of effect on transition from the little bit of messing with it I have done, and then you set a wastegate boost level. Then your only other settings are what RPM it decides to disable the sequential system and go non sequential (or turn the sequential system back on when in decel). I haven't heard of any way to specifically control any of the other solenoids through the PFC. You are leaving that up to the computer.

I don't doubt a Motec and aftermarket solenoids could do a better job. I like the PFC, I still haven't heard definitively what you're supposed to do to make transition better and why it works. Just a lot of hearsay.

TitaniumTT

That right there is pretty much exactely what I was finding in my research and exactely why I wanted to stay away from the PFC - cannot control individual solenoids seperately and independantly. I thought that to be key to achieving a smooth transition on a motor that the turbo's were never meant to be on.

slo

iTrader: (1)

Yes it can, it has too... the stock computer controls the solenoids independently, so does the PFC.

Or perhaps I am missing something in this response.

slo

iTrader: (1)

IIRC he has an after maket EBC, one of the good ones that has a 2D boost/RPM table, the precontrol gets used to control the boost up to the transition, the wastgate doesn't even open.

He did something else unusual, he had replaced the restrictor with an MBC but was still running the stock solenoid, and I believe there where no other chages made.

There is another thread in the FD section where a guy managed to get a perfect 10-9-10 transition with 2 manual boost controllers in place of the pre-control and wast gate control solenoids.