You have got to check out this SR20DETT

[nrcooled]

Hey just wanted to share this with the board. This is a wild setup but from what he says laggy as hell. I will give him a gold star for oringinality and tons of work <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'>
Edit: I guess I could put the damn link (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1840443262)

[boosteds14]

thats what happens when u have only two cylinders pushing a turbo. what a waste

[nrcooled]

I guess he is just selling the turbo setup. &nbsp;It really doesn't make sense to me but that is just my opinion. &nbsp;And he has that setup in a truck <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'>

[TheTimanator]

shouldn't two small turbos spool up quicker than one large turbo? &nbsp;That's a crazy set up <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'> but its not the first SR20DETT I have seen. &nbsp;I think that he has some problems b/c there shouldn't be THAT much lag.

[uuninja]

Should spool up faster. However exhaust plumbing and manifold design have a lot to do with how fast a turbo will spool. Since it is a diy job it may not be as efficient as it could have been.

[nrcooled]

Like boosted said there is only 2cyls pushing a single turbo. &nbsp;Since exhaust gas flow obviously is reduced hence spool time increased. &nbsp;hell mine doesn't start spooling until 3 grand so double that to spool both hence the 5500-6000 spool points

[uuninja]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (nrcooled @ June 30 2002,12:18)</td></tr><tr><td id="QUOTE">Like boosted said there is only 2cyls pushing a single turbo. Since exhaust gas flow obviously is reduced hence spool time increased. hell mine doesn't start spooling until 3 grand so double that to spool both hence the 5500-6000 spool points</td></tr></table><span id='postcolor'>
He probably is using a log style manifold with 2 outlets. I can see why it would be really laggy. I was looking at manifold designs used in import drag cars. They actually split the exhaust ports 2 by 2 to drive the same turbo. A 2 cylender per turbo manifold design would probably be more efficient than a log style with two outlets.

Though I do remember one of the guys or a customer of (don't remember which) made a diy TT setup on his SR. As I remember it he didn't have that much of a problem with lag.

Oh and to clarify my prefious post should have read "two small turbo's should spool faster than one huge turbo".

But obviously they won't spool as fast as a single small turbo <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>. Though I don't think that the math 2x the trubo's = 2x the lag is correct.

[240 2NR]

Doesn't seem worth it to run two t25's to power a car at only 8psi. &nbsp;Seems like the lag wouldn't be worth the mild increase in pressure at the top end. &nbsp;Besides, he's only pushing 8psi, a number the stock T25 is capable of alone. &nbsp;Now if it was sequential and running 15psi out to about 9k rpm, that would be pretty cool.

[uuninja]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (240 2NR @ June 30 2002,1:29)</td></tr><tr><td id="QUOTE">Doesn't seem worth it to run two t25's to power a car at only 8psi. Seems like the lag wouldn't be worth the mild increase in pressure at the top end. Besides, he's only pushing 8psi, a number the stock T25 is capable of alone. Now if it was sequential and running 15psi out to about 9k rpm, that would be pretty cool.</td></tr></table><span id='postcolor'>
There is one thing that you are not taking in to account. PSI is only really a relevant number when it is used in relation with a known constant. In this case turbo size. If you think that 8psi is the same amount of air on a t25 as it is on a t78, then you have some reading to do.

The volume of air flowing from 8psi on 1 t25 != the volume of air from 8psi on 2 t25's. All things being equal, and both setups functioning at their optimum efficiency, 8psi on 2 t25's is roughly twice the amount of air induced in to said motor(this an over simplification, I know).

[Kreator]

Ok dumb question: Is it possible to run dual turbo set up with one (smaller) turbo spinning up another (larger) turbo? Or something like a dual setup with smaller turbo running at low rpms and bigger turbo at high rpms? (something along the lines of using nos at low rpms and then letting the turbo do the job?)

[andrave]

yeah thats been done before, the rx-7 TT and the porsche 959 both used that type of sequential turbo.
i think doing a DIY for that would be friggin hard though.
im not sure about the supra twin turbo or the skyline or other cars thta use twins, but i know the rx-7 has a sort of flap that opens at higher rpms to let the bigger turbo kick in.

[transient]

Supra's use a sequential twin turbo as well, though i'm not entirely sure how it works.

[Nismos14]

if hes spoolin up at 5500-6000 whats the point, when redline is like 7k?

[adey]

That little "flap" you speak of (andrave) is also known (and more popularly known) as a wastegate. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> &nbsp;...I think.
Kreator, yes, it's been done before... but since you don't seem to have known about them, good thinking. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

Transient- the Supra uses sequential turbos!?? I was under the impression that the 2JZ-GTE, like the RB26DETT, used two 'parallel' turbos. But I'm by no means a Toyota guy. (though I do like them Tourer Vs...)