Peak horsepower #s are more for bragging rights and not necessarily indicative of performance. Most people interested in this set-up are interested in spool, and the area under the curve.

Me personally, I am interested in keeping the quick spool that allowed me to get out in front of all the big single FDs , 03 Cobras, and Vettes that I've run, and have enough top end to stay out in front to 120+.

 

ah missed that at the top of the chart.

 

Nice numbers none the less. It's great to see the progress you guys have made. I'll be looking forward to seeing what the car does at higher boost levels.

When you mentioned that the car was still running rich, how rich are you talking?

Zach

 

10.6-10.8 across the board.

 

keep in mind guys that this is on a race-ported engine. I'd like to see this same setup on a mild street port or stock port since I feel a lot of people interested in this kit want it because its more streetable than a t78 and still has the top end kick. But what is the point if you're running it on a race-ported motor - driveability suffers.

 

so what kind of port are they talking about when they say "race" port? anyone have pics of their race port?

 

Mm...I have an idea . Might be a stupid one . Why not run 2 separate boost controllers . One for each turbo . You can set one at a lower boost level and on at a higher boost level .
Would that help that help the low end while still having top power ?

 

no

 

Why are you so hung of on sequentials???
Do you even know what you are talking about?


-Ted

 

I agree. I like the area under this twin kit's HP and Torque curve. This is really nice for street and autocross. Can't wait to see the other dyno graph when it is fully tuned. Then later you can slap on a couple GT2871's! :o)

 

I wonder how my twin GT3071 , semi pp. and jay-tech intake equipped FD will compare??

 

The 3071 will match a pp very nicely up to 30 psi at sea level. Waht hot side are you going with.....and I guess you changed your mind again about spending all this money on 2 turbos????

CW

 

I am going with 0.63 a/r hotsides , and yes I decided to sacrifice and make the car a GOOD overall performer, not just a high boost high RPM monster.

 

I can tell ya in about a month! Except i'll prlly still be on stock ports, and i'll be using a custom sheet metal intake totally diffrent from the jay-tech.

-Alex

 

ill be able to give dyno numbers on my bb twin t04e setup in about 900 miles of break in

 

What TO4e are those and whta are your post? I match up some super 50s to my engine but still scared about the fitting and pumbing.

Does anyone know how a single A/Rs and wheel size for a turbine relates to 2 turbos of smaller size?

CW

 

hmm so two gt30 with 71 trim should spool fine on extended street port right? looking for some .64 a/r....
hehe i wouldnt wanna do a whole project and end up worst then a single!!!

 

We don't know about the spool but the compressor map fits the flow of a pp engine.

 

I have a post about my turbos and setup in the 3rd generation section, thread is called "Just wanted to say thanks" https://www.rx7club.com/forum/showthread.php?t=417896 Im keeping the turbo specs quiet until I get dynoed, but they spool quick, anyone who says they wont hasnt physically driven a car with them, as for the plumbing, good luck its a royal pain, especially if you want true equal length manifold runners, add that to the true dual exhaust and it was a nightmare getting to fit.

 

When will this kit be available for a 3 rotor?

 

Can you direct me to the exhaust barrel ??

 

Any updates?

 

yah whats the latest news

 

Expanding on what Kevin said, his point "A" is valid as to direct comparisons between twins versus a single. Theoretically, if said twins were exactly half the size (with proportional differences in compressor and turbine efficiencies), the twins would spool quicker. The effect of bearing friction is negligible compared to the additional inertia require to spin the larger turbine and compressor.

However, the GT28R is not half of the size of a 35R nor are the efficiencies comparable among compressor and turbine maps. Number crunching indicates spool times should not be much better with twin 28Rs versus a 35R. For example, at 35R will make about 14 PSI at 3500 RPM. On a stock ported 13BREW, this equates to a pressure ratio of 2.2 (with conservative pressure drop) at 20 lbs/min (corrected). Using the same formula, but halving the flow for one rotor, a 28R will still have the same pressure ratio (As Max so eloquently pointed out), but have to do this at 10 lbs/min. The compressor maps say it ain’t so. We would expect 10 lbs/min at a pressure ratio of 2 or about 12 PSI. A ported motor will do better, but not necessarily in proportion to the enhanced flow rates. If you wanted the same boost response (with a stock port motor), the GT22/52 trim would fit the bill.

OTOH, the two GT28Rs will outflow the 35R but a good margin, so big HP can be expected from such a setup.

Turbine efficiencies are another story. Two 28Rs will prove more efficient and, again make more power.

In contrast to Kevin, I think this setup will generate a bit more heat than a single. The “larger surface area to exchange heat” using the twins will also require removal of that heat (exhaust temps to each turbo should roughly be the same as with a single, ceteris paribus). Additionally, since these turbos are roughly 2/3 to ¾ the size of a 35R each, the combined radiant surface area (compressor/turbine housings/downpipes) is greater resulting in higher under hood temperatures.

Back to your regularly scheduled program…

Gene

 

So whats the latest on this ?? , any more dyno numbers ? . I am finishing up my seup and would really like to see what this kit can do , so that I can get an idea of what to expect from mine ! , would I be making 500rwhp @ 15 psi ????