90Rexx

so i could potentially be doing a twin turbo setup on an SOHC civic this winter for someone. The setup will include a small turbo, like a T25 style turbo, and then a larger T3/T4 turbo. Can anyone give me some input as to how i should configure the exhaust side? such as should i just run a regular turbo manifold, then the exhaust from one turbo runs to the other ect?

i understand this is not a very cost effective way to gain power.. my customer is more looking for the "bling" factor of twin turbo... so im enetrtaining doing this setup.

also feel free to chime in about other issues i may have such as oil feed lines to each turbo ect.

95civhb

You could run a custom manifold, and run a small turbo off each pair of cylinders (seems to me you wouldn't want to run it sequentially because of firing order... somebody chime in on that?), but that would seem rather pointless... I'm thinking you might have some clearance issues...

I'm thinking an advantage with going that route would be that it would be easier to tune...

the idea of using a smaller turbo to spool a larger turbo is fairly common in the diesel world... not a lot of gas guys do it.. I'm guessing tuning is the difficult thing with that.. maybe get ahold of a potential tuner and talk to them about it... it'd definitely be cool to see though!

there are probably some more knowledge guys/gals that could chime in on this..

turbojdmhatch

been done on a b series...guess its possible with a d series...good luck getting it to run correctly

vadimkag

Go back to homemade turbo lol

spoolin turbo s

what about using these from a 93+rx7 i don't think i've ever seen anyone use these turbo with any other type of setup


well first off unless your using too identical turbo's then its not going to be a "twin" turbo setup

I'd make it with the smaller turbo feeding the larger turbo tells how much power your wanting to get out of this and we could help with turbo choices

also how much money is in the budget for the turbo's?this very important to decide on turbo choices

let me know the budget for the turbo's and how much power you want and ill give you my opinion of what turbo's you should use

if the budget is small i can tell you 2 junkyard turbos that would work
if the budget is big i can tell you 2 garrett gt or 2 bullseye borg-warner turbo's to use

let me know i'd like to see how this goes , because anything different is a real interest to me for doing something different

NonovUrbizniz

as above... you'd want to run the smaller turbo first then have it's wg and DP run into the inlet of the larger turbo...

It will definatley work but it's probobly not going to be too efficient... the smaller turbo will start to choke out once the larger turbo spools... you might have to do twin 38mm or larger WG off the first turbo so once the pressure gets too high on the exhaust manifold side for the smaller turbo it just WG dumps it into the intlet for the larger turbine....

Definately going to be a tricky setup though as you'll have differenent WG pressures you want the small turbo's WG to open at and the larger turbo to open at... also the additional pressure in the larger turbo might back up on the smaller one... you may need to have anti-reversion tubes between the small and large turbo... although that's still not a gaurantee.

Definately an interesting idea and I've always thought that it "could" work out great... but then you look at cars like the RX above and the older sequential dual turbo S4's and the first thing EVERYONE does on those is to pull those off and put on a larger single turbo... they just make more, and better yet more efficient power.

90Rexx

thanks for all the info so far. The guys budget is minimal so im looking at using possibly Some junkyard T25's. probobly going to be going the "twin" route instead of the sequential route. two T25's should make for a decently low spool time and with two of then churning i should get some decent volume of air out of them. i can imagine using identical turbos is also going to be easier to tune, and i also wont have to worry about jimmy rigging a crazy WG setup for each turbo dumpnig into the next ect.

anyone have any opinions on how they should be setup as far as manifold design? is 2 cylidners really enough to spin a turbo or should i have one turbo just dump into the next?

also any input on the oiling situation? im worried running an oil line to each turbo might drop the oil pressure too much...

Tony the Tiger

It will be fun and peppy with a twin turbo setup, and to grab a lot of attention at a local Honda meet...lol. I managed to get a crowd of 50+ people around my car and all I told was a few friends about it.

Eventually though, the TT setup did not perform as well as I've expected.

I did mine a few months ago with a built B18C1 and twin GT2860R's.. I first started with a custom sequential setup utilizing the factory Supra TT OEM hardware (compressor intake control valve, exhaust control valve, vacuum storage tank and solenoid, pre-spool function, all controlled via ECTune) and managed to spool one turbo up to 20 PSI at under 3500RPM. Unfortunately, our motors are too small and whenever the next turbo kicked in, the VE of the motor greatly increased and boost instantly drops way too much. After several days of dialing the sequential setup on the dyno, there was no way to make the two turbos spool up in a controlled systematic fashion. Under a full load pull from low RPM on the dyno, it managed to get a pretty smooth curve with minimal dips. But once I've held the RPM to around 6000RPM and then go WOT, the second turbo kicked in way too late (turbos were tuned via boost vs RPM vs TPS vs duty cycle) and never worked out. Load changes all the time, and on a MAP sensor based system, it is IMPOSSIBLE to dial it in. With a MAF sensor, yes maybe with a bigger motor, but not a MAP system when PSI does not mean HP/TQ and engine load.

I've then reverted to with a simple parallel TT setup (removed all the valves, re-did the exhaust/DP) and it gained a good amount of midrange as well as boost response. I had twin GT2860R turbos (rated for about 33 lbs/min each) and it spooled 400-500RPM faster than a single turbo rated nearly identical (GT4088R). On the streets, the turbo managed to achieve about 4-5 PSI at low RPM's, and takes a sec or so to get that boost at low-mid RPM's which made the car really peppy in traffic and regular driving. The two smaller turbos were efficient at low exhaust flow, and the setup had some good useable torque around town.

However, once I start winding up the two turbos up to their max rating, the twins did not carry the inertia like a big single turbo. Boost would drop out between shifts, and boost builds slowly at higher RPM's (it takes a lot of winding up to get up to 24+ PSI). In the end, it was a lost cause, and since I am a huge fan of instant boost and high engine response, I went back to the single.

I didn't bother making a new thread about it because of the lack of interest here on Honda-tech (I try not to post up boring material for the folks here)... But if you need any info, just PM me.. I do not suggest going with any sort of a sequential turbo setup. After researching and testing for weeks, you must have a bigger displacement motor to be able to carry out a sequential function properly. A high revving Honda motor is the worse candidate for a sequential TT setup of any sort.

Here's are some pics and a vid:



http://www.youtube.com/watch?v=CZpjigAbIY0

90Rexx

cool great info.....thanks alot. how did you do your oil lines? just 2 lines running off the pressure sender with restrictors at the turbo?

nonpoint986

do a compound setup...this is where i learned how to do it. perfect referance also.

http://www.dsmtuners.com/forums/cust...bo-set-up.html

spoolin turbo s

2 t25 off an eclipse or if you wanted 2 that were even smaller you could get the 2 turbo's that come on a 300z tt, or 2 k03 turbo's from a 2000+ mk4 gti, jetta, or beetle
you should talk to tony as he is a very resourceful and helpful person
he could tell you which cylinders should be paired together with the manifold or possible could even buy his manifold and replace the b flange with a d series flange if that would work

the VW turbo's are extremely reliable even when abused way out of there efficiency range

let us know how it goes, and what you decide to go with.......the twin route would be much easier than a sequential setup

there was a guy that did a twin turbo with 2 small t3's on a ls.......on homemadeturbo.com if i remember correctly it had really nice powerband

i think the find it on where all the old guys on site went to a site called realhomemadeturbo.com after someone no one liked bought the old site

tony how was the turbo's setup in that video? and are any of those cars you have listed your daily? if i had all of those it would have to be sleeper camry for me. Is it still on stock transmission?

g230sport

idk **** about turbos, but that rx7 idea is damn near the coolest ive seen. i could see that def working, couldnt you pretty much use the rx7 setup, and just make a flange for it, and get it all welded up?

only problems i could see would be space and clearances...

89turboaccord

something like this would be cool.

http://www.turbos.bwauto.com/products/r2s.aspx