Da1spaz247

Inspired by a thread I read a long time ago on HMT,
http://www.homemadeturbo.com/f...19375
and a pair of Supra twin turbos falling into my lap, I decided to do something a little less common than all the other turbo honda's on the road. I was just about to do a t3/t4 on my built lsvtec (already have the turbo and parts) but this oppurtunity came along and I decided to make a change in direction.

I am WELL AWARE that twin turbo 4cylinders are generally LESS EFFICIENT than single turbo setup. I am WELL AWARE that I will most likely be sacrificing power by doing two turbos, rather than one. Frankly, I do not care. I would rather have something a little more unique, therefore, I will proceed.

That being said, here is a little more info on the setup...

2 Supra turbos
Ls Vtec with forged internals and block guard
gsr cams, AEBS intake mani, Hondata IM Gasket, ITR valve springs, etc
HKS bov, not sure what size charge piping to use yet
JRC intercooler
750cc injectors, walboro 255, Motorola Map sensor
My goal is 300-400 WHP

The plan is to start out by using the stock turbos in the configuration they sit in a supra, so I can still use the cast upper-downpipe pieces, which goes to like a 3in outlet. Then all I have to do is build the manifold to go to each turbo. Then I'll join the hot side charge pipes with a y-pipe and it will be like a single turbo setup from there.

Biggest thing people say is that there will be lag. I would like to use the best size charge pipes to help reduce the amount of lag I'll get from running two turbos. Also, I thought I read something about a supra in stock-form spooling one turbo at a time by regulating the wastegates individually to decrease lag, anybody know anything more about this? And Last, would I be better off with a higher compression ratio to help spool-up time?

I'll be posting pics in the next couple days of what I got so far. Thanks in advance for looking, and any constructive criticism.


Modified by Da1spaz247 at 3:19 PM 9/18/2007


Modified by Da1spaz247 at 6:41 PM 11/29/2007

White Smoke

Those turbos are still kinda big for only .9 ltr. In for updates

Unsivil_audio

No, the biggest thing isn't lag. Its that your doing twice the work and using twice the parts than you would with a single turbo setup. And thats not hate either, twin turbo setups sound sweet.

Now first things to address, are you using the same sized turbo's from supra's? Meaning, I always thought one turbo was sized smaller than the other to help minimize turbo lag (I know thats how the factory FD rx7 setup is). Then the larger turbo would spool for top end power.

Also compression has no effect on turbo spooling characteristics. Displacement spools turbos, not compression.

tokesGTR

Both supra turbos are the same size. They use a complicated setup that directs ALL exhaust flow into one turbo initially for quick spool, then brings the second turbo online later for more top end power.

And charge pipe size isn't going to make a tit of a difference for lag, so think again.

integraRS-T

i hope u good luck wit ur setup but i know a local guy wit twins on a civic and its slow as ****

Reyke

hope it works hey don't feel bad a lot of people thought the turbo I put in my prelude would never spool, but whos laughing now

In for the updates

Archidictus

If unique is your goal, Godspeed Just as long as you're not doing it for function, you're alright in my book.

Topdawgg

Twin turbo = just for show

and for the newbs that have no idea what a turbo setup is....
when you say TWIN TURBO, people go nuts... its hilarious... but the real turbo guys just laugh..

Da1spaz247

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Unsivil_audio &raquo;</TD></TR><TR><TD CLASS="quote">Also compression has no effect on turbo spooling characteristics. Displacement spools turbos, not compression.</TD></TR></TABLE>

But wouldn't higher compression make more power, creating hotter exhaust which would help spool? I thought people always say higher compression with turbo spools quicker but is a lot more difficult to tune without it detonating. I'm thinking about aiming for around 9.5:1 - 10:1. I need to cc my b16 head to calculate what my compression ratio really is, because I don't know for sure if this head has ever been shaved.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tokesGTR &raquo;</TD></TR><TR><TD CLASS="quote">
And charge pipe size isn't going to make a tit of a difference for lag, so think again.</TD></TR></TABLE>

Why wouldn't it? Larger diameter pipes have more volume for the turbo to fill up before reaching positive pressure, so tell me how that wouldnt make a difference?

As for the complicated single-double turbo exhaust switch, it sounds like if I can get it to work on my car (I dont see why not), it would really help spool time. And if it worked well enough, this setup should work out pretty damn nicely. I'll have to examine the turbos more carefully and verify this. I do remember one of the wastegates looking kind of funky.

blwn95civic

i think it'd defenately be unique. I know where your comin from with this b/c it seems everybody has the same setup or very simular setups these days.

lambertincorp

good luck in for numbers and times

PhantomX

Finnaly! someone steppin up to the plate and doing this!! Post pix when you have some... I want to see this!!!

red_crx

iTrader: (2)

Good luck...I've personally never seen a twin turbo setup in person before. Crossed my mind back in 2000, but never tried it.

This link might be of some help to you:

https://honda-tech.com/zerothread?id=1973959


have fun!

Doostur

Good luck on the project. Subscribed.

Unsivil_audio

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Da1spaz247 &raquo;</TD></TR><TR><TD CLASS="quote">But wouldn't higher compression make more power, creating hotter exhaust which would help spool? I thought people always say higher compression with turbo spools quicker but is a lot more difficult to tune without it detonating. I'm thinking about aiming for around 9.5:1 - 10:1. I need to cc my b16 head to calculate what my compression ratio really is, because I don't know for sure if this head has ever been shaved.</TD></TR></TABLE>

Thats the theory, but as we've seen real world tests say otherwise.
http://forums.evans-tuning.com...=1612

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Da1spaz247 &raquo;</TD></TR><TR><TD CLASS="quote">
Why wouldn't it? Larger diameter pipes have more volume for the turbo to fill up before reaching positive pressure, so tell me how that wouldnt make a difference?</TD></TR></TABLE>

Because the amount of time difference between filling 2.5" charge pipes and say, 2", charge pipes, is literally milliseconds. Personally I wouldn't go any smaller than 2.5" It'll do you good, I promise.

I'm unfamiliar with the sizing on stock supra twins, any a/r's or trims? They're t3's correct?

I would use a external wastegate setup, it'll be much simpler. Personally dont even worry about how fast turbo spool is until your done building it and have driven it. Chances are you'll be completely happy with it.

Da1spaz247

Unsivil_audio, Thank you for that link. That answered my question exactly! I'll go for the lower 9:1 compression ratio. Not sure on the trims yet, hopefully I'll be picking them up tonight so I can snap some shots. They looked pretty tiny to me when I saw them, smaller than a TD04.

And, I should have added about the charge piping that I was thinking there would definately be a difference, but I didnt know whether it would be measurable. Like you said, milliseconds.

As for external gate, thats not a bad idea, but I want to finish looking into this two-stage spool thing before I decide whether to utilize the system or not. I've already got a good external wastegate if I decide to go that route.

turbosi03

Regarding the two stage spool setup, what if you use 1 external waste gate to regulate boost on turbo A. Feed downpipe from turbo A to turbo B inlet, Also merge wg dump tube into down pipe before turbo B inlet. Then have second wg to control boost on turbo B. Make single dp for exhaust from turbo B to muffler etc...

Not sure if that's a generic sequential setup or not.


Modified by turbosi03 at 4:21 PM 9/19/2007

Da1spaz247

hmm, interesting idea. A little more complicated than I was hoping though. I'll think about it a little more.

Here are some pics from the same turbos that someone is selling on ebay, mine are the same thing.

Notice how small the turbine housings are? That should help spool time eh?




Hope he doesn't mind me borrowing his pics, lol.

Now, looking at that, maybe you guys can help me decide on a manifold design. I could build a log style so all four runners are connected, more even flow to each? Or, I could do an equal length tubular manifold with runners 1 & 4 to one turbo and 2 & 3 to the other. Hmm.

Unsivil_audio

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbosi03 &raquo;</TD></TR><TR><TD CLASS="quote">Regarding the two stage spool setup, what if you use 1 external waste gate to regulate boost on turbo A. Feed downpipe from turbo A to turbo B inlet, Also merge wg dump tube into down pipe before turbo B inlet. Then have second wg to control boost on turbo B. Make single dp for exhaust from turbo B to muffler etc... </TD></TR></TABLE>

Thats what I would for simplicity sake, that way he's only dealing with one downpipe instead of worrying about how to merge two. Also, this way he could mount 1 wastegate on the manifold itself that could regulate boost for both turbos. And if that wasnt good enough, 1 more could be mounted on the pipe between the two turbos.

turbosi03

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Unsivil_audio &raquo;</TD></TR><TR><TD CLASS="quote">
Also, this way he could mount 1 wastegate on the manifold itself that could regulate boost for both turbos. And if that wasnt good enough, 1 more could be mounted on the pipe between the two turbos.</TD></TR></TABLE>

Well from what I was thinking, the first wg wouldn't be able to control both turbo's because I suggested to run that dump tube back into exhaust before the second turbo... So there's less wasted gas energy.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Da1spaz247 &raquo;</TD></TR><TR><TD CLASS="quote">I could build a log style so all four runners are connected, more even flow to each? Or, I could do an equal length tubular manifold with runners 1 & 4 to one turbo and 2 & 3 to the other. Hmm.
</TD></TR></TABLE>

I don't think you can do a sequential setup if you use two cylinders per turbo. Need to figure out if you want a sequential or parellel setup.

Unsivil_audio

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbosi03 &raquo;</TD></TR><TR><TD CLASS="quote">Well from what I was thinking, the first wg wouldn't be able to control both turbo's because I suggested to run that dump tube back into exhaust before the second turbo... So there's less wasted gas energy.</TD></TR></TABLE>

Good thinking I must've missed that.

alterdcreations

Then you want a bigger second turbo so it wont cause too much back pressure.
maybe that small supra turbo then a big t70 .

Da1spaz247

That does sound like a cool idea, but for the sake of keeping cost down, I'm going to stick with using both of the supra turbos to start. I think I am missing a few pieces to make the factory sequential system work, so I need to look into that before I decide if I'm going to be utilizing that or not. If not then I'll just do the parrallel setup, which would be nice and straight foward at least. Looking at these turbos in person again makes me think that spool wont really be an issue. They are pretty tiny.

Da1spaz247

WOW... so much for simple. Here is a link that explains how the system works. Its called SSTS.

http://www.lextreme.com/sqtt.html

I am going to bounce this around in my hollow head for a while and see if I can come up with a slightly more simple way to make the system work for me. One thing that would help would be not being terribly concerned with a "smooth" transition from one turbo to two. I will need to get a few of those control valves from a supra owner too.

This is going to be fun!

cptengineer

It's already been done. It was a baby blue CRX back around 1998-2000 on the east coast and was an apexi car. Had poor results, I talked to the guy and I believe he said he had problems with tuning and other BS, cant remember. maybe some one here has a pic, oldschool