Lithium

You have the 20G eh? If so, thats not surprising - looking at the bigger picture from places where people have tried everything under the sun the 20G seems to give the GT3071R some real work to do, both seeming to drive similar and deliver similar results. The general impression I have is that the GT3076R gives basically nothing noticeable away to either (in terms of driving experience) but has the ability to generate a decent amount more power, which is one of the reasons you'll find in the big picture GT3071Rs aren't that common a choice given they bring nothing more to the table than a 20G for a bigger price - or as a balance, less to the table than a GT3076R for the same price.

Gutted about the coil, damn Skylines - good work on the dyno and autocross though, testament to the overall setup! Can we please finally see a decent RB26/EFR dyno plot?

Why are people talking about the 3566, isn't that just some rugged big old Garrett wheel thrown on a GT35 core to make a bit more power? Its not a Precision turbo, and odds are ultimately a frankstein thats not likely to be worthy of comparing to the turbos mentioned in this thread.

I am definitely a lot more sold on the new Precision CEA turbos than I was the older Precision units, very impressive results - though for what you describe there I still favour the likes of a ForcedPerformance HTA GT3076R, if not HTA GT3073R for an SR. Those things have an awesome reputation for response versus their normal Garrett (etc) counterparts, and just happen to punch above their weight too... the Precisions in that size range from all I've seen also punch above their weight, but tend to be a bit laggier too.

The new Precision PT6465CEA is now out and Sound Performance have tested it out against a PT6266 and PT6766 on a couple of different engines. First is a bog stock 2JZ running E85 on 36psi: Then just for prosperities sake they ran the same turbos to their limit on a fully built 3.4litre: Interesting to note that the 64mm made more power everywhere on the stock motor running "less than maxed out", the 67mm only came into its own when everything was pushed to their limits - which really shouldn't be too surprising.

I have more info to share on this, but I'll put it in the Precision turbo thread....

The 2J is mental, its a 3.4litre stroker running an angry head and 9.5:1 compression - good motor to get the best out of a turbo. Slightly OT, but from the same car the initial test was a PT6266 vs PT6766 vs a PT7175 - they just maxed out all turbos and posted the results: SP have also tested a new PT6466CEA which the results for are flabberghasting. Looks like a fricken awesome unit for a street 3litre. Naturally the power delivery and power levels are mental because of it being a big angry 2JZ - but its all relative. The EFR8374 is known to spool similar to a GT3582R, so the PT6266 etc are very very impressive for the power they make.

Speaking of twin scroll EFRs on 2JZs, heres an interesting dyno comparison - twin scroll EFR8374 maxed out on E85 on a Supra, compared with a PT6266BB (single scroll) doing the same: Tuner says intake air temps and exhaust manifold pressure were lower on the Precision turbo.

I feel the same way about both, and am somewhat envious you have both in the garage- especially with modern TS BB turbos tangling off them.

The extra 200cc Piggaz' car has would make a big difference. Sounds really promising so far man, I'd not be overly surprised if you got in the territory of your 430kw target at 25psi just on pump gas. Don't be shy on E85, lets see 500kw

Geoff - I thought for some reason you were going 7670 on the EVO? What fuel, boost etc are you going to push the S14 to? Very keen to hear how that goes, good luck sir... it'd be nice to finally start hearing nothing but good results from these things.

Nice, sounds like its on its way to being a bit of a monster - I bet it sounds awesome Whats the exhaust note like with the twinscroll setup? What turbine housing are you running, and what is response like? So 375kw was pump gas - right? If so, with 25psi and E85 this is going to be a weapon! Very cool!

I know that, but as soon as the surge goes it will be spooling as per normal - as will be evidenced by the fact that the wastegate is open. If the wastegate needs to open, the shaft speed is MORE than it needs to be... simple as that. Thats what VCT is there for, make more torque sub 5000rpm and will also make surge less likely by eating more of the air from the 20G. Should improve spool slightly too, more VE = more gas flow = more turbine driving.

GTScoTT - Easy way to prove you theory would be to pull the wastegate hose off and do a dyno run or a 3rd gear pull, if it doesn't free boost then you're quite right - my money is however on their being no issue with shaft speed, and that the wastegate is earning its cash keeping shaft speed down by those rpm... and I'm pretty sure people mentioned wastegate noise earlier on, which would imply that is definitely the case.

That would be pretty surprising...

Very very nice result - getting VCT working might actually help with the surge too.

Yep it was in that range on the dyno I tuned it on and it seems thats the generally accepted range for that type of setup on that type of boost. I didn't mention numbers as people on here get all weird about dyno types - so stuck with the basic facts, this is the kind of performance you should get with a stock RB25, stock manifolds, decent exhaust intercooler and ECU and about 17psi running on 98RON. Tune and all else being equal the real world results shouldn't vary too much, regardless what kind of numbers on what kind of dyno.

That reminds me - here's a .82a/r internal gated GT3076R setup with similar power: Its over 250kw, not quite 300kw - so doesn't answer either of the specifics but still gives an idea of what a very basic internal gated GT3076R setup can go like with a safe tune. That turbo is capable of much more on more boost/better manifold/external/cams etc, but still makes for a good all around setup.

^ Totally agree, especially with a GTX - I keep meaning to come in to add that 2c. RB25 and RB26 don't spool turbos much different at all, I've actually experienced both an RB25 and RB26 with equivalent cam specs, manifolds and .82a/r GT3582Rs and they both made very similar power and hit 20psi at 4300rpm.

Thats pretty sweet, cheers for sharing that - it shows that being pedantic about the little things really can make a difference between a "happy" and "not so happy" similar setup equivalent.

I acknowledged that some might, after changing tyres etc

Difference between this car and a mid 8s @ >170mph Supra is with this car you'd be able to take off the parachute and then lurk off into onto normal roads and have a comfortable drive home. You'd be home before the Supra has been loaded onto the trailer/street legal exhaust and tyres put back on. I can't wait till someone strips one of these AMS GTRs out and puts some slicks on them.

Surely he would have noticed that? Gotta be really really worried if he didn't! Noticed the boost plot was for the 1bar run though.

On the high boost run the lines are all over the place presumably due to a misfire, whether its dodgy tune, dodgy coil, valve float or something different - who knows. The build up of midrange looks good, I definitely wouldn't blame the turbo for the poor 1.4bar result... some issue needs to be resolved. Could end up pretty good once sorted Other than that, more subtle bumpiness in dyno plots are often more to do with "smoothing" the dyno software does on the data it gets from hardware than how than the car is actually running. The data generated from the dyno is less than perfect, if it were plotted in its raw form it'd look more like a bunch of random dots with a general trend which might look a bit like it could be a curve. The software has the unenviable job of finding a delicate balance of making it into a curve while keeping as much of the finer detail as possible but also keeping it "readable". Smooth it too much, and you could lose useful information - smooth it too little and it could end up just looking like a random lightning bolt. Also, the more you smooth it the lower the reading will be as it effectively draws the "highs" and "lows" closer together. While not a dyno example, this is the kind of thing that will be going on: Whats the ECU/Engine setup?

Awesome job! Looks fantastic, shame there are no power gains there but still a very sweet project and it'd be nice to think you may have improved response etc, +1 for video clips so we can hear the goodness We learn nothing by doing the same thing all the time.