My Twin Turbo setup. Insight encouraged, Flaming not allowed!

ASSISTANCE Forced Induction
1

Inspired by a thread I read a long time ago on HMT,
http://www.homemadeturbo.com/forum/index.php?board=1;action=display;threadid=19375
and a pair of Supra twin turbos practically 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 finally finish a t3/t4 setup on my built lsvtec (you may remember me from “the road to 300 whp” thread) 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 more than 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- running the SSTS system
Ls Vtec with forged internals and block guard
gsr cams, AEBS intake mani, Hondata IM Gasket, ITR valve springs, etc
HKS bov,
JRC intercooler
750cc injectors, walboro 255, Motorola Map sensor
My goal is now 300-400 WHP

The plan is to start out by using the turbos in the same way they work in a stock supra. If you are not familiar with the Supra Sequential Turbo System, here is a link…

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

It basically directs the exhaust from all cylinders into just one turbo first, then the ecu switches to true twin mode at a certain rpm/load.

I’m going to be building a log-style manifold (needed for SSTS) and I need to get in contact with Ben Ogle to see if he will help me program two more outputs from the ECU to control the VSV’s (all part of the SSTS). This is what the turbos look like…







Look how easy they made it for me. With this, I only have to deal with 1 intake pipe, and 1 intercooler pipe, and 1 downpipe!

For tuning, I will be using the vtec trigger wire to trigger the turbo #2 instead of vtec. This way I can have a seperate map for when the second turbo spools up. Otherwise the ecu wont be able to differntiate between one turbo at 10lbs and two turbos at 10lbs. Then I’ll use a new programable output to switch on vtec. I’ll use the second new output to trigger the pre-spool on turbo #2. It will happen like this…

Accelerating from say 1400 rpms… Turbo #1 only will be spooling. At 4k, Vtec engages. At 4600 or so, turbo #2 will begin to pre-spool. at 5k turbo #2 will fully spool and join in on the fun. Then i’ll quickly hit the rev-limiter at 8800rpms, lol. Of course I’ll have to experiment with what rpm each of these events will take place to find the best combo.

As you can see, I’ve been putting a lot of planning into this, and I’m quite excited to make it happen. I know it’s a lot of info at once, but let me know what you think!

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I’m having trouble seeing pictures. Is there a reason you chose supra turbos?

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I fixd the pix

4

this is great and I hope it works out well. Keep us up to date with pictures, progress and the inevitable frustration from such a project. :salute:

5

none of your links and pics works mang:whisper:

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intrested to see how this is gonna turn out. looks like you have done your research.

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:corn:

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linx fixd. Also, I chose the supra turbos because I recieved a random phone call from an old friend that said, “hey I got a pair of turbos from a Supra for sale, are you interested?” Then I thought maybe I’ll rebuild them and sell them for more. When I saw them in person, I thought “Shit, why don’t I just use them on my car? I could actually save money by using these and selling my one turbo! Plus how many people can say they have a TWIN TURBO Integra!” That’s when I began doing research and learned about the SSTS system, and that’s when I decided I had to do it. I just loved the idea of being challenged and being the first to do this successfully.

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im with DH on this one, diffinatly sounds like youve done your homework on this one and im eager to see some progress on this.

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Now, I understand your reasoning and I want to make sure you know I’m not being an ass on this one. I know I’m known as one of the site dickheads but I have some honest questions.

  1. Are you aware of the Apex’i twin turbo Integra and its designers’ conclusions that everything they did could have been done with a single turbo?

  2. Don’t most Supra owners opt out of the SSTS system for either a parallel or single turbo setup?

  3. When all is said and done, will you be satisfied enough with just being the first to do something knowing that you could’ve achieved the same result [probably] cheaper and easier?

  4. How are you going to fit that thing in the engine bay, and how much fabrication are you expecting to have to do? How much are you anticipating the electronics troubleshooting to cost?

Like I said, honest questions. I’m of an engineer’s mentality (that is, doing the most with the least) so my personal stance would be getting the furthest with the least amount of work and money, and from what I can see the only thing that would be a drive to do this is the “I’m the first” factor… otherwise it doesn’t hold much logical sense to me to go through all of the work just to end up where Joe Nobody got with his ebay kit and 8 hours worth of work in his Dad’s garage. I’m open to the fact that there may be a lot to it I don’t see, so I’m genuinely asking for you to enlighten me a bit.

:up:

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dH, I wonder about you sometimes!
Anyways, I though the same when I saw this thread, I figured that it’s possible but not practical. I can’t understand why someone would spend the money to over build a motor without the intentions of using it to it’s full potential. I can’t seem to understand that line of thinking.
Example… Sleeved block, pistons, rods, ARP, complete valvetrain and their goal is 250 whp.

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Good questons, and I’m glad you asked!

  1. Yes, I am aware of a few twin turbo 4cyl setups that do in fact work, but not as well or the same as a well matched single turbo. One of the reasons it was taking me so long to finish my single turbo setup on my car was because I was losing interest in a project that had already been done 234762958721985 times before. This is my chance to do something that will be different. I like different (Don’t get me wrong, i’m not a goth or anything, lol!). And I’m not trying to “break new grounds”, or try to make it better than a single setup or anything like that.

  2. Yes, most supra owners get rid of the SSTS for the sake of simplicity, and because these turbos are small and they want more HP. Because of the SSTS, you can’t just swap in bigger turbos and retain the system, unless Toyota made bigger ones with the same unique turbine housing on the second turbo.

  3. Yes. Like I said, it’s already been achieved easier a billion times. But, keep in mind this will actually be cheaper. Let me point out that the assembly you see in the pics above cost me $100. My single turbo cost me $400 for a decent (at best) T3/T4, and then I had to sink another $250 into rebuilding it (needed new shaft, bearings, and seals). Plus I now have no need for my external wastegate, so I get to sell that too. And building this custom manifold will be cheaper than the one I bought.

  4. I’ve already put it in the engine bay. Since I’m using a civic radiator with a push fan, clearence shouldnt be a problem. I’ll have to fabricate the log manifold (I’m going to cut, fit and tack it and have a professional finish it with a Tig) and I’ll have to have the flanges for the turbos made, which wont be a problem. Then I’ll have to fabricate the intercooler piping and downpipe which you have to do with a single setup anyways.

As far as electronics, I’ll be using the stock ECU with my Ostrich and WB02. Or, if that doesnt work out, I’ll have to use 2 rpm switchs (not as much flexibility with programability as I would like). Neither one is expensive.

The Supra had 320hp completely stock, and was said to have usable boost as early as 1800 rpms. I know that I’m using the same turbos with almost 1/2 the displacement, so I’m not quite sure how they are going to work for me. And I’m glad I have the chance to be the one that finds out FIRST HAND, instead of always reading about other peoples experiments.

Believe me, I’m glad you asked those, I don’t want to miss anything in the planning of this. Got more? Keep em coming.

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That’s awesome. Normally I’d be the first one in line to be on the hate committee, but I can honestly say I’m really looking forward to the outcome of this one.

As for what I can see off hand, you’re going to have a problem with spooling and electronics. The electronics part is tedious but “easy,” since all it will take is someone knowledgeable sitting there with it until its done. The spooling problem is a different matter. I don’t know engine dynamics as well as some people but I’m not sure half the displacement equals exactly half of the exhaust energy… I think it also has to do with compression ratio and number of cylinders as well (due to losses in the exhaust flow out of they cylinder into the manifold). This can be inferred from the observation that similar boost lag on a Supra isn’t necessarily had from a turbo twice as big as one on a comparably lagged Integra.

I guess the short version of what I’m trying to say is, the system is not as complex as it appears on the surface when you break it down. Not counting fabrication and electronics, the only thing I can see being a big problem is getting that first turbo going. I don’t know turbos too well and I don’t know where the “spooling” or smaller turbo size on the Supra fits relative to those spun by Integra engines, but if full spool on the first turbo gets too close to the 4600 threshold you’ll have overlap issues with both your powerband and your electronics. The only way to solve it would be to change or modify the first turbo to spool sooner.

Again, I don’t know turbos that well to know if the first turbo is small or large for a B series engine… I’m just talking what I would infer from observation between the two engines and their differences.

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Damn! Now all I have to do is win over Junkman and Armed Farret and I’ll have an ego so big my head won’t fit through the door, lol!

Anyways… I know what you are saying with the spool time differences between different number of cylinders, displacement size etc, I too do not know the mathematics involved to accurately estimate the rate of spool on each or both turbos.
According to a thread I read from Evans tuning http://forums.evans-tuning.com/viewtopic.php?t=1612
, compression has very little to no impact on spool time, even though its counter intuitive. So I’ll aim for 9.25-9.75:1. It should be a good balance of pre-boost power and heavy-boost tunabilty.

I do know that each turbo appears to be smaller than a TD04 turbo, so they’re fairly tiny. And I don’t know if I want the first turbo fully spooled before switching to both, or halfway spooled or what. I can’t control when #1 begins to spool, but I anticipate it to spool very quickly because it would “in theory” be exactly the same as running it as if it were a small single turbo setup. My guess is it will reach a full spool around 2.5-3k rpm under a good amount of load, and that’s being conservative.

I’m thinking that if the setup works out the way I want, but I can’t reach my peak HP goal, then I’ll look into swapping the compressor side of one or both turbos with that of a bigger toyota turbo. If it spools too slow, I can always downgrade to the JDM 2JZ-GTE turbos, they’re actually smaller than US ones… go figure.

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that could be pretty cool if you get the thing tuned right. thats gonna be the tricky part. id like to see it work. still cant believe you went this route when u already had the t3/t4 though. good luck!

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good luck.

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That’s all you got for me Armed Ferret? Come on now.

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you expected something more?

i wanted to subscribe to the thread for the updates. :wink:

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:rockon: Well… da1spaz247 can do anything he put his mind too. He has helped me with the build of all my db2’s. he in addition has done a RHD del sol with a b16. He did my friends celica GT-Four 3s-gte swap. and too many others to list. So i know he can handle and research all that comes up. BUTT kyle get your car on the road!!!

later

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don’t doubt it. just subscribing to the thread is all. :slight_smile: