1sicsol

Ok guys hear me out. I'm having some trouble seeing the benefits on going single turbo, after all the dynos Ive seen, turbo kits, work,time, energy and the high costs to go single single turbo there really isnt much improvement on numbers compared to the potential of the twins. Considering this situation that most have a budget, and its usualy a leading factor in decision of going single. Im considering a single turbo BUT I need other positive outcomes that out way my negative outcomes.

I consider these three things as questionable (negative) factors in going single.* Please be advised Im speaking for the 13rew and 3rd gen rx7, pump gas only on RELIABLE boost settings.(not 20psi)*

1. It seems now about/ or almost 400whp can be detained on the twins with popular mods and tuning.

2. Consider that you rarely see over 430-450whp on single turbo on pump gas IF you get that... most single dynos I see are under 430whp anyway.

3. So why pay $3000 for the kit plus maybe an install for the same power or 30whp more? I dont see the value/point here. Why is it worth it spend all this money when you cant ever detain over 430whp anyway reliable on pump gas when you can nearly have just as much on the twins?

Another example:
Is it worth the $3500 for the gt35/40? it would nearly make the same hp as the non-sequential twins but with less lag? so less lag costs=$3500? this is no good.

I'm no expert and I encurage feedback others regararding this, because I need to learn what the big deal is besides the purpose of say "my fd is single turbo"

vspecpgt

there are lots of threads on this that you should be able to find if you search.

i'll give you 7 reasons because you have an rx "7".

1. less heat.
2. less complicated.
3. more efficient (sp?)
4. more power.
5. cheaper to rebuild.
6. wide variety of selection relating to boost response/max power
7. just plain looks cooler.

if you need more, just search using the above parameters.

1sicsol

Less heat is good and I see that as a good point. Ive searched and notice that everyone overestimates the power they might make on certain turbos. When you look at the dynos lieing around its far less then most claim that a turbo will make.
This is why I wanted to start a thread so that I dont start thinking to bias against single turbo when infast I may be wrong.

SlvrRexx

400whp on stock twins? and pump gas? wow, that **** ain't stock engine.

Zero R

iTrader: (1)

Doing this requires you to run the **** out of the stock twins not a very smart idea, I would rather make 400hp on lower AIT's


This is true but you can save a lot of complexity to your overall system, making it lighter(about 25lbs in some cases) easier to diagnose. Generate less heat when set up right, less back pressure, more efficient AIT's

Please see above, also why run something on the ragged edge when you can run 400hp and then still turn it up if you want to go to the track(room to grow).


$2999 and it kills me to see posts like this, how is it no good?????? just a few years ago people would have been paying HKS $5 or 6K for the same thing, and loving it.
running non-sequential puts stress on the primary turbo which will lead to premature failure, is less responsive, generates more heat, weighs more, leaves a lot less mess under the hood.


In the end it is up to the person wether or not they feel they want to spend the money, there are many benefits and few draw backs, it just depends on what it is worth to that person. Look at it this way If you make the same hp as you would on twins and reliablity and headaches are a concern, I will take 15lbs on a 35R over 15 lbs on the stock twins every time.

Dwood432

Ride in a single turbo FD. You might just change your mind

Like the others said, making 400 hp on the stock twins will significantly shorten their life. Is it worth it to make 400 on the stock twins and rebuild them all the time?

Wargasm

Realistically for 300 rwhp, just stick with the twins in sequential form and you'll be fine. For 400+, forget it. Even if you do squeeze close to that out of them, they won't last long.

Fd3BOOST

iTrader: (7)

This seems like a misinformed statement. At best you MIGHT squeeze 360hp off stock twins. This also as everyone else mentioned would put them under an excessive strain and they would not last long.

Things are not as they seem.

This is a fairly generalized statement. There is a huge difference in twins @ 15psi making 360hp estimated, for say a 35r @15psi easily making over 400hp.


You will still have to buy the supporting fuel system and EFI control. Which can easily cost another 3-4k.

Your starting to sound like my wife here D: There is simply no excuse for the need of more speed. Also 360hp isn't anything near 430 hp.
Just to drive it home more you will have a better system then the one your car was sold with. It's less complicated. It's more efficient and it offers more potential for speed. I thought it was pretty much the natural progression to want to go faster..

Black97VR4

Like everyone else said, you might get close to 400rwhp on the 99 spec twins but you're not going to get anything resembling reliabilty out of them.

A single turbo gives you so much more versatility. The 450rwhp a single makes on the street is lightyears more reliable than the 360 or so that the twins are just barely spitting out. Then when you got to the track you can run race gas and make 500rwhp+.

Then if something ever did happen to your single, most can be rebuilt very cheap compared to the twins.

We must then factor in all the heat that the twins generate that will no longer be in the engine bay, how much less cluttered it will be, the simplicity of having only a couple vacuum lines and no more rats nest. All of this leads to a more reliable car.

I've missed many points as well. All in all going single is a great thing if you can afford. The difference between single and twins is night and day.

blueskaterboy

anything with less lag than nonseq and i'll be happy.

i've ridden in a few FDs with stock seq, stock motor, running 12-13psi and it is NOTHING compared to my ported motor with nonseq, midpipe. the only thing i liked was the absence of lag, but you shouldnt be at a low rpm when your racing anyway, and lag is actually pretty nice in stop and go. i dont boost all the time. and for normal driving i shift at 3k so its pretty nice.

as stated by everyone basically you dont have to push a single as hard to get the same power, many of the smaller or ball bearing turbos spool almost as fast, less heat, less bs.

finally about a year after i kept asking about that apexi turbo, theres a dyno. now if i can get my hands on it for less than $5k !!!!

gfelber

For a street car, you can indeed make decent HP with the stock or modified stock twins. 400 RWHP stock or modified stock twin cars are exceptional cases, though it is possible to get a decent 360 RWHP (not as easy as one might might be led to believe) out of such a setup. Spending another $3,500+ for 40 HP or so may not be worth it to some, but HP is not the only factor to consider.

As Sean et al. mentioned, run these twin turbo cars very hard and you're asking for trouble as the turbos are performing well outside of their efficiency range. In fact, the entire turbo system (manifold, turbine housings, etc.) is performing outside of it's range. This shortens turbo life; causes cracks in exhaust manifolds, premature failure of vacuum lines & gaskets, generates excessive heat, and dramatically elevates intake temps and EGTs- factors which will most certainly shorten you motor's life.

The most compelling argument, IMO has to be improved reliability of the turbo system itself. If you've ever had to troubleshoot a persistent (and often intermittent) functioning sequential system you can appreciate this. Even stock twins run in parallel have potential issues with failing vacuum lines, seals and solenoids. There is also the issue of boost creep, even when manifold/WG porting is purportedly done properly.

I was absolutely fed up with the sequential transition above 4500 RPMs as it was affecting my performance on the track. This is a real handful (and potentially dangerous situation) when trying to balance the car through high speed corners during transition to full throttle. A finicky turbo control system which occasionally locks the turbos in parallel mode around 4K is a pisser too. I tried running the car in sequential mode and the boost threshold (some call it lag, but this is not correct) was much worse than with a properly sized single.

Finally, 400 RWHP single turbo cars seem to be the rule rather than the exception. A single turbo + fuel system + tuning + computer + enhanced cooling (about $8K) + misc other stuff is not a cheap proposition and you'll also have deal with the emissions police. However, this was well worth it for me. The siimplicity, reliability and elegance of design makes this car a much more pleasurable car to deal with on a day-to-day or year-to-year basis. And I can always turn up the wick

Gene

Poweraxel

Please use the SEARCH button. you will find many compelling reasons to dump the stock sequential twins

SPOautos

Let me tell you one MAJOR reason people go single.

They blow thier engine and now thier twins are dead. No one does cheap rebuilds anymore cause there arent any quality rebuild kits out there. This leaves with going for upgraded twins or 99spec twins both of which cost over $2K.

So here you are, you have your new engine sitting on the ground, your looking around at all the HUGE pile of **** that your going to have to put back in the car and you just say **** it and decide to leave it all out. So now your going to be running non seq which means lag. Hell if your going to pay over 2K and have some lag you might as well spend a little extra and go single.

Also, dont forget about putting things together yourself. You can get a real nice 62-1 setup for right about $2K with a nice manifold and everything. Obviously you'd need the supporting mods to make over 400rw but your still need the same supporting mods to make that power on twins as well.

Anyway, just thought I'd share why a lot of people end up going single.


NOW, if you dont have all the supporting mods the most economical route to take is some BNR stage 3 twins for about $2K that will bolt up like stock.

To be honest though, all you guys that think the twins create huge ait temp problems....well, I've never seen that. My air temps didnt budge under boost with a good IC. I think what the problem was is that people had IC setups with a lot of pressure drop and they were running the turbos out of thier eff range.

Anyway, good luck....hope you figure out what you need/want

Stephen

Zero R

iTrader: (1)

I definitely have on a few customer cars almost all are run out of their eff. range when they came in here as you stated below.The other problem is just because the AIT's are low doesn't mean the turbo's themselves aren't generating way more heat than they should, just means you've patched it with a better cooler.

Jason

iTrader: (5)

Rob,
When you bring your car down we can talk about your options. One way to go would be ported motor, Non-Seq/ported manifold running around 15lbs of boost. We have a few cars running that setup making 360-370 RWHP. The question is how long will the stock turbos handle that. Most of these cars arent driven on a daily basis.
Another option is ported motor, small single turbo. I have a couple of kits that will be out in the next couple of weeks. One is a GT35R for under $3k and have a couple that will be in the $2600 range. They will give a more reliable setup in the long run with the possibilty of more HP depending on boost.

Jason

apneablue

I have the GT35R...Basically I went with this becuase
1. I wanted more power than the stock twins
2. I wanted something easier to work on

There is such little support with this car unless you live next to Gotham, RP, RX7Store, or other...I wanted more power reliably..

The last time i dynoed on my stock twins at 14psi with all boltons I got 317rwhp...I felt that was pushing the twins a bit much...especially if you daily drive it. Now running the 35R at 12psi it pulls much harder than the stock twins at their peak HP (that I saw) and the turbo is still 5psi away from its sweet spot.

Single = good
twins = Not bad, but not good as single

gfelber

Totally agree. I made 362 RWHP with the 35R at 12 PSI and the car wasn't fully dialed in. Unfortunately, we toasted the clutch so I couldn't do any more runs.

Gene

apneablue

What clutch were you using?

gfelber

Well, I'm embarassed to say it was a stock disk with a HD PP. We weren't surprised at all Going to try an RPS 6-puck with HD PP.

Gene

Zero R

iTrader: (1)

Gene I am guessing your happy with the kit then?

gfelber

It freakin' rocks! I'll post a big write-up on my website when I get the final tuning/clutch done (and I get the website back online).

Thanks a bunch!!!

Gene

Zero R

iTrader: (1)

Snook

iTrader: (12)

you cant make that much power on the twins and if it does happen its not permanent.
you'll just have to ride in a car to get the feeling.
it costs WAY more than 3000 lol seriously about 10k and a shitload of time on labor and thinking. its only for people that strive for their fd to be the best and need more power. if you are happy running 14psi on the twins having 335rwhp and pushing the **** out of the poor things then stay with it. If you are bored with the speed then its for you

ZoomZoom

iTrader: (2)

The GT35R kit is a great street kit. It offers alot. Ive owned one.
The Twins are old. The manifolds crack on all of them. The Heat is high. I noticed a huge drop in water temps when i went to a single. Also the replacement cost of stock twins is the same of a good single kit. So why replace with stock twins? You have more power potential , Much much more reliable boost pattern. My stock twins would fluctuate alot due to how hot the car was. My single boosts the same every time. Its also more linear. The stock twins are all over the place. Also you can turn up the boost on a single to 29 psi and run race fuel (with the right fuel system) and smoke any stock twin car.
So why buy a single? There is a real question waiting to be asked. Why replace stock twins with another set of stock twins for 3k?

Boosted!

Whats up Jason? This is Mike's thread. (Mike with the silver FD that came down to rx7store with me in The summer)

Anyways...i will talk to you on the weekend