Full-race's new toys
It's difficult for the masses to grasp some of this discussion, simply because it isn't evident to many here that spool characteristics and transient response are not a simple, two-dimensional affair, such as what is displayed on a dyno chart. It isn't easy to imagine what's happening. It simply must be driven to be fully understood, and that isn't a readily available option for most. This being the case, it will be a leap of faith for many at this point in time.
I have nothing to promote, nothing to sell. What I can say from first-hand experience with my own car (PT67R), and from first-hand experience with Drifto's car (GT3076R) is with the twin-scroll setups, the big turbo reacts much faster to changes in throttle position, and that makes for a much more responsive, lively feel to the car. I can definitely relate to the track experience and 2 sec lap improvement as quoted above, and I don't doubt it for a minute.
I have nothing to promote, nothing to sell. What I can say from first-hand experience with my own car (PT67R), and from first-hand experience with Drifto's car (GT3076R) is with the twin-scroll setups, the big turbo reacts much faster to changes in throttle position, and that makes for a much more responsive, lively feel to the car. I can definitely relate to the track experience and 2 sec lap improvement as quoted above, and I don't doubt it for a minute.
here is another 3071R graph on another mostly stock SR20DET where they compared it to a 2871R single scroll. whats interesting to note here is that the 2871 spools LATER than the 3071. This is counterintuitive in that they share the same exact compressor side, so the smaller GT28 turbine should spool faster due to its size. In fact, the bigger twinscroll 30R turbine is outspooling it due to the increased turbine efficiency that the twinscroll affords
check out the nissan plots above, should be a little more inline with what you are used to? Also there are a number of Full-Race singlescroll 3076R dynos on this site if you wish to compareI have read the great thread from cover to cover, and realise there is lots of expectations of you re this TS set up being the Holy Grail of resolving Lag... My experience with TS vs single is that TS tends to be more responsive and drivable as you press on the gas (either on part throttle or as you slam on WOT). The spool time is marginaly better, especialy on a large turbo bolted to a 2L. On a 2,3 - 2,4 its a lot better with full boost coming up to 300RPM earlier, in real world comparisons. on a 2L if you get 150RPM earlier spool its a lot! Top end power always suffers more with T/S because its now got more restriction to deal with
additionally, if you are losing top end, you have flow problems. While it is true that a twinscroll housing will have more exhaust gas friction, the pulse conversion spool benefits at low rpm combined with the anti reversion/scavenging benefits inherent to the twinscroll have a significant upside. If you lost top end something else was wrong with the setup
Funny, but back in the day, there were many discussions on the merits of transient response on www.theoldone.com. Most thought the guy was crazy. However, he really IS a genius of sorts. It's a good read, and there are great articles on what Geoff is trying to get across to some of our thicker headed members on the merits of transient response!
Nice....I take it no one makes a twin TS 30R setup for the Evo yet? Im kinda off witht the turbo numbers....3071 is the 30R and the 3076 is the 35R right?
Last edited by Turbo Kyle; Jul 24, 2007 at 07:19 PM.
actually they are both 30Rs. A GT3071R is the small 30R, and the GT3076R is the big 30R. The second two numbers in the title indicate the outer diameter of the compressor wheel in mm, the 3071 is a 71mm OD and the 3076 is a 76mm OD
the 3071R has a closer turbine to compressor match indicating better response, slightly better spool, and slightly reduced backpressure. This is the turbo preferred by our time attack test driver and our drift pilots. This turbo can do just shy of 500whp
the 3076R has a larger compressor. It can make more power than the 3071R but has slightly later spool, and slightly slower response. Most of our customers (and most evo guys) actually use this turbo and are still VERY happy with the response and spool, and they can be a bit more competitive on a drag strip. It can make a bit over 530-540whp
the 3071R has a closer turbine to compressor match indicating better response, slightly better spool, and slightly reduced backpressure. This is the turbo preferred by our time attack test driver and our drift pilots. This turbo can do just shy of 500whp
the 3076R has a larger compressor. It can make more power than the 3071R but has slightly later spool, and slightly slower response. Most of our customers (and most evo guys) actually use this turbo and are still VERY happy with the response and spool, and they can be a bit more competitive on a drag strip. It can make a bit over 530-540whp
Last edited by Geoff Raicer; Jul 24, 2007 at 07:29 PM.
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When will we see Evo-specific results of the twinscroll? The info so far is nice, and I don't want to be a wet blanket... but so far it's only speculation that these FR twinscroll setups will superior to other Evo offerings. Again, not to be a naysayer, I'm just pointing out the situation.
Didn't you do any testing before releasing them??
Edit: and by testing, I am referring to testing on an Evo...
Didn't you do any testing before releasing them??
Edit: and by testing, I am referring to testing on an Evo...
actually they are both 30Rs. A GT3071R is the small 30R, and the GT3076R is the big 30R. The second two numbers in the title indicate the outer diameter of the compressor wheel in mm, the 3071 is a 71mm OD and the 3076 is a 76mm OD
the 3071R has a closer turbine to compressor match indicating better response, slightly better spool, and slightly reduced backpressure. This is the turbo preferred by our time attack test driver and our drift pilots. This turbo can do just shy of 500whp
the 3076R has a larger compressor. It can make more power than the 3071R but has slightly later spool, and slightly slower response. Most of our customers (and most evo guys) actually use this turbo and are still VERY happy with the response and spool, and they can be a bit more competitive on a drag strip. It can make a bit over 530-540whp
the 3071R has a closer turbine to compressor match indicating better response, slightly better spool, and slightly reduced backpressure. This is the turbo preferred by our time attack test driver and our drift pilots. This turbo can do just shy of 500whp
the 3076R has a larger compressor. It can make more power than the 3071R but has slightly later spool, and slightly slower response. Most of our customers (and most evo guys) actually use this turbo and are still VERY happy with the response and spool, and they can be a bit more competitive on a drag strip. It can make a bit over 530-540whp
Nice...thanks for the info again....are the turbine wheels the same size on the 3071 and 3076?
depends, haha just kidding they are. what changes is the turbine housing from manufacturer to manufacturer. i'm sure there are different 30 serious wheels too but i'm pretty sure they're all generally the same.
Last edited by trinydex; Jul 25, 2007 at 10:31 AM.
When will we see Evo-specific results of the twinscroll? The info so far is nice, and I don't want to be a wet blanket... but so far it's only speculation that these FR twinscroll setups will superior to other Evo offerings. Again, not to be a naysayer, I'm just pointing out the situation. Didn't you do any testing before releasing them?? Edit: and by testing, I am referring to testing on an Evo...
there are two 30R turbines: the small 56.5mm (for use in internally wasteagated T25 flanged 3071s) and the bigger 60mm (found on the external gate 3071, 3076, and 3082). Those are the 2 GT30R turbine wheels
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that turbo was really designed to be used on nissan SR20DET engines where they use the stock style bottom mount manifold and a standard t25 o2 housing/downpipe. Doesnt really make much sense to use it on an evo...