FDNewbie

iTrader: (10)

Something I haven't fully understood yet is why so many companies (greddy, hks, etc) and shops specialize in single and twin turbo kits, yet no one offers a sequential twin turbo kit??

I asked one guy one time who makes turbo kits, and he replied "yea I can do it, if you bring me some Mazda engineers" lol.

I guess I'm missing why it's so difficult to do...given that you wouldn't be starting from scratch. Don't you have a template to either use or at least copy from, be it from our or supra's turbos?

And I don't beleive it's simply due to a lack of demand...as a lot of people are big sequential fans, yet upgrade to a single since the stockers can only push so much...

ijneb

BNR sells upgraded twins? Pettit sells highflow twins... the 99 spec twins flow more.. A-spec also sells a kit with two T-25's (I think) I must have missed the point of your question, or you havent shopped around.
-Ben

prew

iTrader: (9)

i think hes talking about something like the twins on rx7store. something that can make single turbo power without maxing themselves out, i dont think any of the hybrid twins can.

steve prew

FormerPorscheGuy

Sequential twins are commplicated, if you don't believe me then look at our rats nest.

911GT2

Well, the turbos themselves don't dictate whether they're seq or not, the control system does. As ijneb pointed out, you can get aftermarket upgraded twins from a bunch of places and run them sequentially.

And if you're talking about having an aftermarket bolt-on sequential turbo kit for a car that is otherwise not-turbo'd or not seq turbo'd, then theres a whole list of reasons. First and foremost is the complexity, hence the turbo builders reponse to your question. Second is the price. The R&D time on something like that would make the price for the kit probably well over the $10k mark, which no one would buy. And third is the demand. The seq system on our cars always has issues, why would someone take their otherwise probably reliable car, and add an overly complex turbo system to it?

FDNewbie

iTrader: (10)

Yea I guess I should have restated my point...

The 99s and the BNRs use the stock housings, correct? Ie, there isn't THAT much of a difference over the stockers (99s are good for what...300ish hp? The BNRs are rated at right around 400hp.) Prew's right...I'm talking about completely upgraded twins (larger twins) that are run sequentially, and can make some serious hp #s.

Sure, sequential is complicated, but I also don't think it's impossible. And running twins at like 18+ psi at 60% efficiency isn't what I have in mind, ya know?

Like 911GT2 said, there's a wide variety of aftermarket twins you can pick up, but none of them are set up to run sequentially. Have any of you heard of someone who makes a control system to run these aftermarket/upgraded twins sequentially? Cuz that's specifically what I'm looking for, and have never seen...

johnisenglish

You can certainly fabricate a sequential turbo setup using entirelly non-stock parts, but it would require quite a bit of time, money and planning relative to a single turbo setup, and for the vast majority of applications its just not worth it.

MakoDHardie

It would be a waste to install some current technology high performance compressor groups on the same small, cracked, restrictive manifold. In order for it to be worth it, you'd have to fabricate a new manifold and to keep it sequential, install the little flapper in the manifold and then configure the compressors onto some sort of custom turbine housing that can allow them to share the same source of exhaust gas for spooling and then a new y-pipe substitution would have to be fabricated if the setup didn't fit right up on the stock one....probably wouldn't considering how small the stock compressor outlets are and the stock y-pipe is made for them.

Singles and twin kits as we know them (not BNR style upgraded twins), are much easier and more efficient to produce because they're a simper, and better, exhaust manifold, normal turbos, and a custom downpipe. piping to the intercooler is fabricated by the buyer so that isn't stress that's added to the manufacturer. Once you get rid of the sequential setup, you could go on aobut the differences between twins and single setups, but they share the same principle. Just two separate rotating groups instead of one big one.

FDNewbie

iTrader: (10)

Do you know someone who could/would do such a thing?? Eg., garrett t-25s can flow enough for 500hp (from what I understand), but running them parallel would give you considerable lag. Imagine if you could fabricate or even modify the sequential control system on our twins, and use it to control these t-25s. That would be incredible...reliable 500hp sequential twins. Is that too much to ask? Or too far a stretch??

t-von

iTrader: (8)

I don't think it's too far fetched. It's just that fabricating a single set-up is so much easier to do.

Personally, I would love to see someone put forward the effort using todays technology and engineer a much better manifold that will support upgraded turbos. Then engineer the set-up so it can be run off of the stock actuators. Too bad the Fd left our shores at such an early age because someone probably would have engineered something like this by now.



Edit: I just thought of something that could work better! I'm not possitive but was there talk about using an electricaly assisted turbo charger for the hydrogen Renesis? If so, manufactures could use something similar to assist a larger single turbo in the lower rpms. Think about it......the electrical turbo would run (depending on load) in the lower rpm's while the larger single is getting spooled up by the exhaust as normal and eventually joins in at full boost. Plumbing should be easy because only the compressor side of the electrical turbo would be plumbed into the piping of the exhaust driven turbo. In the end you would have the advantages of the stock seq system while being far less complicated, with reduced heat and making more hp. What do you guys think?

z8cw

Try TEC in Golden, CO...they rebuild turbos and make custom application. I know he uses the original manifold, rebuilds and modifies it and then mates it up with different turbos. Not sure what power they are supposed to make.

Claus

PVerdieck

Because it isn't worth it. The market isn't there for that. It is a hassle to do all of that for twins, especially for a car whose total US production run was so low. In addition, monster single solutions are there for those wanting more power.

The best question, would be is there a JDM solution for this? If not, then you sure won't see any US solution for this.

FDNewbie

iTrader: (10)

Good point. But there are quite a few twin kits in Japan, although all are running parallel.

BUT...given what you said, ok, it may not be financially worth it given that there isn't enough demand. Yet I take it that it CAN be done, eh?

I'm gonna check out TEC...I thought I heard about someone a while back who got some upgraded twins from them, correct?

T-von, your idea sounds very intriguing...

SPOautos

The reason is no one would pay for it cause it would cost a fortune. Think about the manifold design with all the flappers and doors and actuators involved. Then there is the new Y pipe that would be needed. It would be complex to fab everything up then rework till it actually runs right and has a good transition. Then you'd be hard pressed to sell 50 of them, especially at the price it would need to be. I dont think the RX7 store has ever sold even one set of those twins on thier site cause the price for twins is soooo much more. Then you throw in the WAY more complex manifold design and the new Y pipe with an actuator controlled flapper. Then you have the whole intake setup that probably wont bolt up which is another issue. You need twics as many oil and coolant feed lines and drain lines as compared to a single kit.

It just goes on and on and on. It would be extremely expensive to design, build, test, and having running properly then you'd have to sell it for such a high price that everyone would just get some single turbo kit that costs $2500 less.