Lithium

With that amount of money, you're definitely braver than I am. I'd feel much more confident going with something like a Borg Warner EFR7064. On paper the GTX3071Rs looked good, but now the GTX prove to be laggier - and a GT3071R is virtually identical in spool to a GT3076R... I'm not sure the result is going to be worth it.

If you can get one for equal to or cheaper than a GT3076R, otherwise a GT3076R would make more sense.

The GTX series turbos seem to be laggier than their GT series counterparts - so while a GTX3076R flows better than a GT3076R, its also laggier. It makes it comparable to (and this has been proven) to a GT3082R in terms of power and lag. The problem with that you pay the price for a fancy new turbo that does nothing better than a previous already existing unit. In effect they are bigger compressors in terms of flow, cost and lag but with equivalent naming and the same flow on the turbine side - meaning things like a GTX3076R stands to choke, which could also be the case with a GTX3582R though thats just speculation.

I will say my 2c the last time, I think the GTX3076R is a waste of time and money. Use a normal GT3076R, if you want more power go a GT3582R.

Of course, except the GT3582R was running apparently around 30psi all the way through - the EFR8374 was running less boost in the high rpm according to the owner. GT3582Rs aren't known to crack 700whp - some people will argue 650hp is more than you'd see at the hubs from one

I am betting pretty similar spool wise but I'd not be surprised if the EFR is running a little more boost - more so than anything because the GT wouldn't have been any point pushing any more through.

Another result from someone with an Integra running a built K20A on race gas who went from a .82a/r GT3582R (around 650hp @ hubs) to an internally gated EFR8374: If I read it right, the owner believes that with a stiffer wastegate actuator so can holds 30psi to redline could yield some substantial gains - he is pretty confident there is a fair bit left in the turbo. Very impressive gains over the GT3582R with no more lag!

... because you felt like doing something redundant Very true Toyota give better factory support systems for their motors. However the 10second stuff, there aren't that many people who have even given the RB25 the opportunity to run 10s - Australia is probably one of the bigger modifiers of RB25s and it seems 80% of you put undersized turbos on them, its only been recently people seem to have started being more sensible with them imho. Of course if people put 400hp turbos on RB25s and 700hp on 1JZs the 1JZs are going to go quicker! You feel somehow like 40kw down with only slightly less lag would be faster overall? You should have just gone a smaller turbo on the RB25 as you had already started down that path - imho. It sounds like you had already done something silly to your motor somehow. I've done 90,000km running 1bar+ on a GT3076R (which I put on at around 100,000km) and my motor is still going strong despite all sorts of weird situations its been through. One of my friends has a 2JZGE Supra and his motor is more tired than more ffs. Car publications (particularly the far selling Oz ones) have a lot to answer for in terms of providing ill informed or biased opinions based on pub talk or whatever and having crowds of sheep treat it like scripture. I love the HPI issue where they compare the VR38 and the RB26 and they site long rods as a major disadvantage, then rattle off a bunch of completely back to front reasons that long rods are bad. Excellent

And a RB26 is a ridiculously short stroke.... RB30 has the same stroke as the current Type-R Honda motors run

Dodgey lecturer, balance the bottom end properly and it should be fine. I wouldn't be revving a normal VL RB30E over 7000rpm - but if you are going to build a new engine those generalisations don't apply.

No. A mate of mine has basically the same mods on his RB20DET as I have on my RB25DET. We both have upgraded turbos on stock manifolds, stock motors, aftermarket ECU and fuel system etc. My car is tuned on BP98 at 17psi and makes 301wkw, same dyno his car tuned on 30% ethanol and 21psi makes 295kw. He gives me a bit of a run for my money on midrange torque - probably more to do with extra boost and better fuel, but his falls flat at 6000rpm and mine keeps making more power. On the same fuel and boost I have roughly 50kw on him, better off boost torque and way better midrange. No comparison.

Very nice results Might have to try runs like at some point I am around a hub dyno again to see what the numbers look like to get an appreciation of what cars run at Status are like.

How?? The turbo builds boost slower than one with the 82mm GT series compressor.

I think you are missing the point, basically 17deg is the most timing you should be able to get in there. He said that going higher resulted in knock, not that he was getting knock there. The reason I asked what power and timing levels people are hitting in Oz with those setups and dynos is thats the best easy measure of where people are reaching the max stable cyl pressures as measured on a DD dyno with that fuel, so really there is no reason I can see that he should be trying to push timing further than that. He has reached the limit where everyone else has, so there is nothing different or wrong. If he wants to push more timing into it than that (and the only reason you'd want to do so is to try and make more power) then he probably needs to look at an inherant change of some sort. The obvious/simplest one to go for is to get some alcohol into the fuel flow. It'd naturally be a good idea to do whats possible to cool intake charge (as always) but going from other peoples results, all thats going to do is increase the safety margain.

Thats what I was thinking too, glad I asked... I thought I might have been going mad or something. I suspect there is no problem, the car is making what you'd expect on that boost, with that fuel, with that turbo

How much power do you guys normally expect to make on BP98 at 17psi on an RB25? And how much timing are you expecting to be able to put into it?

OK I am even more disappointed with the GTX3076R than I thought I would be. I had said before anyone tried results than I suspected it was going to be more or less like an expensive GT3082R, but it actually looks laggier than I expected it would be. To be honest I am starting to doubt that the GTX3071R will be as awesome as I thought it would be. Now it looks like its probably going to end up with (baring in mind there is pretty much no noticeable spool difference between a GT3071R and a GT3076R) a GT3076R which makes slightly more power with slightly more lag. Hardly worth it. My prediction - when more Borg Warner EFR results come in, the GTX turbos are going to be made to look stupid. Not convinced here. The GTX 76mm compressor appears laggier than the GT 82mm compressor, which has imho a better overall pumping efficiency. Its basically got nothing on it, going from results I've seen so far. The GTX 76mm so far seems like an expensive waste of space to me. Why bother with a GTX3576R when there is a perfectly capable GT3582R which appears like it'll have no more lag, at least worth mentioning?

To make a low compression RB24?? I'd use the RB25 rods too, personally - a little more rod length couldn't hurt.

Bugger... won't necessarily show the real comparison

Awesome, very very keen to see how that goes on an RB25 - should be good! Any details on the engine spec?

Tuner should probably be able to see symptoms of this while tuning - thats with the CAS. I'd also expect this to be an obvious issue at all boost levels.

Only reason I asked for the map was I wanted to see what was happening with timing and fuel in the higher load zones, IMHO at 14psi its making reasonable power for the boost level - so the fundamental flaw isn't related to the engine's inherant ability to use air and make power... there is something that changes when it goes from 14psi to 18psi. If the tuner was having to do weird things to keep everything happy, I thought it might be a clue given its the closest to having the car right in front of me. The power curve tracks the previous one - usually with a boost leak or a restriction of sorts the curve will change shape a bit, but in this case it actually looks like the boost level is different but its hardly reflected at all in torque or power anywhere in the curve. At the moment it seems easiest to blame the inlet manifold, though there are apparently other cars which have made more on the stock one on pump gas - I haven't seen any in person myself however, as most people seem to go aftermarket after 300kw.

On pure non-alcohol fuel? That hp rating will be based on 91MON I'd say.

I'm guessing it could just be a very "peaky" compressor map... higher boost it might offer more flu

I'm not convinced there is such a thing as a master tuner. Sure, people will get better at it but at the end of the day its just a brave sod who reads a bunch of clues required to reach an end point and takes the necessary steps to reach said end point. If they are lucky and the end point set by whoever put the car together is a good one then the tuner stands to achieve God status when in fact they just did what they had to do. If the end point was always going to be a bad one, then their name can easily become mud for just providing an inevitable result. There will obviously be people with varying degrees of ability to read the clues and take the best possible steps to be able reach the inevitable - but so long as you are reading clues and realistically taking guesses (however educated) you're never the master of the situation If someone deems themselves a master, I'd personally approach with caution... as I'd say from my experience with this so far its a game where the old "The more you know, the more you know you don't know" thing runs very true. You stand to learn a lot very quickly, so pay attention. Just my opinion, of course.