Lithium

OK, in terms of exhaust noise vs diagnosing this kind of thing - even if the exhaust itself hasn't suffered a collapsed muffler or cat (worth investigating) the sound can change and hint at other issues. - Suddenly louder can mean the wastegate is jammed open for some reason, or had some kind of mechanical failure. Remember, it leaks exhaust past the turbo which will be the most effective muffler in your exhaust - Suddenly quieter on full boost could mean your wg is not opening as much, or at all. This could suggest a boost leak or something along those lines - meaning your boost control is going full effort to try and hit target boost, and there isn't as much (or any) exhaust being bypassed around the turbine... DEFINITELY something you want to sort if it is happening. You shouldn't need a 4-port mac valve for a 2port actuator. You can actually use two 3ports plumbed to push and pull to similar effect, as well.

Haha I just recently saw a tuning post from a YB guy complaining about how rubbish the twin scroll 7064 is and that his old T3 was better. I suspect very much it's a setup issue as I know the 7064 isn't rubbish, but still amusing

Haven't seen much of the Gen2 GTX3076Rs, but I'd take an EFR7670 over a Gen1 GTX3076R from what I've seen. An EFR7163 would be a beast on an SR, though if you are going for high rpm there is a chance of choking it - I'd use the biggest housing you can get on that turbo.

I guess I don't know what turbos you are familiar with, but I feel like the most sensible way of describing one is if you were looking at something using "back in the day" turbo terms - its in the area of a Trust/Kinugawa T67 - Garrett GT3582R power wise but wanted better response (just to clarify, I'm not saying it will be like a supercharger - just something that is in that power range with less lag) then you should be happy with it.

Yeah, definitely noticed that - ANNNNND in the most "harsh" correction mode Dynapack dynos offer. No two ways about it, this is making some big power with a very wide delivery.

The Dyno plot I posted was the highest before they got nitrous involved

That's just bollux. What a ridiculous power delivery haha. For those who didn't watch the video - check out this power delivery, 300kw at 4000rpm on something holding power to 8500rpm... Like 875hp power. There isn't much to question there. Cheers for sharing!

Mph lie when you're looking for how a car delivers its power in situations other than drag racing

Nice! To be fair, this is a dyno result thread and posting a time slip but still no dyno sheet makes baby jesus cry. Very interested to see the delivery of this

(y) This is the post that got my attention btw: https://www.facebook.com/nzwiring/photos/a.263208990533912.1073741827.263205613867583/915378341983637/?type=3&theater

The dyno run attached does look quite a bit like it could be VVT turning off too early, I'm assuming that's sorted now? Saw a post on NZ Wiring's workshop page of a very similar setup/workshop which upgraded to an NZ Wiring CAS setup on an RB25 Neo recently, wasn't you by any chance? Very solid delivery for an RB25 making that kind of power, though. Should be a fun drive

Very nice! Can you please share the dyno plot? The peak power is solid, but not the most interesting part of that setup

Hahah that looks pretty familiar. I do very similar, before matchbot I just had an array of spreadsheets I used but MB does help/make me a little lazier than I used to be but handy because I don't have as much spare time as I used to so anything which makes it easier ftw. It's kinda handy that it dumps all the working out so you can effectively map turbine flow maps from other manufacturers out by adjusting the turbine expansion ratio and monitoring the turbine corrected flow, just making sure that you take into account the correction factors used for each. He's effectively talking about how much leverage is applied to each side of the WG, you need an ECU which can control two separate boost control solenoids independantly. One is for controlling how much "opening force" is applied to the gate, and the other for how much "closing force" is applied. If you can apply the full boost pressure to holding the gate closed, and non of the boost pressure to opening it - then you in theory can go way past the sprung pressure... but being able to fine tune both sides means you should be able to limit erratic behaviour as you reach boost targets. The closest to this you will achieve with the typical "single direction" boost control setups is using a 4-port boost control solenoid - the example you linked is slightly simpler again, "single direction" but with a 3 port solenoid which means you never have the option of applying full pressure exclusively to either side of the gate.

Gotcha. This is on the OS 3.15? It hasn't got a big tube manifold or something, has it? And with the turbine rpm pick up tests are you doing it on the road (ie, where there is gearing and weight of a vehicle involved) or is it steady state against a dyno? Depending on that lot, what you say paints the picture that could be interpreted to say that inertia isn't your primary problem and that it's got a lot to do with how your exhaust energy etc is being harnessed. 13Bs I guess aren't exactly lacking in creating exhaust energy I guess. That short-runner/high exhaust energy thing is why I kinda view twins as a no brainer on Vs and singles, and it'd be nice on the straight 6 if it weren't for the fact that everything was so cluttered that the benefits are arguably some what scuttled by the fact that pushing exhaust gas into the turbine isn't the only factor involved in making an engine perform What kind of spec is the best power vs drivability RB-based setup you're encountered so far?

There is actually some info on twins, a member has been running twin EFR6258s on a "good" RB28DETT setup in a track car for years and also tried the EFR7163s briefly. Here is the dyno results with the EFR6258s: And his comments on the EFR7163s:

What size engine and what kind of setup are you talking about re: this 3500rpm test btw? 3.2 with an EFR9180? I doubt Borg Warner are going to do a big enough EFR to justify an upgrade from a 9180, though I don't know for sure. How much of a rush are you guys in to change? Fairly safe to say that there is very likely to be changes in the turbo market before the year ends...

The only people I know who may have a chance of providing this kind of data is @bri73y or @Full-Race Geoff

That's pretty interesting, and pretty impressive really. I would not be in the slightest surprised if the rpm delta improves going to twin EFR7163s, to compare this kind of acceleration it'd be more accurate (though not perfect) to compare tip speed. 60,000rpm/s rate of change = 286m/s/s acceleration, which you need around 77,000rpm/s to match with the EFR7163s. I've never seen any inertia data and I've seen people make big assumptions one way or another, I'm not going to do the topic the injustice of me speculating wildly on that like it could be easy to fall in to. If we're going to end up with some real world data then we may as well wait for that and see where everything sits - hopefully there aren't other variables at play, like manifolding as close to equivalent and engine spec exactly the same otherwise it'll lose the meaning a bit. There really are two different discussions happening here though, from what I can tell - and it's probably worth identifying it so we're not all talking cross purposes. 1) Are the EFR7163s a better match for what RICE RACING is trying to do? By the sound of it, quite likely. 2) Are they going to be more responsive and/or drivable than a single EFR9180 with all other things equal - I'm not so sure, but very interesting to see. If they manage to be then that is a HUGE thing.

Sounds good! It'd be awesome if you do get some results, both dyno and real world. There is no magic or mystery in the idea that if you can make decent use of 25% more flow that you will go faster, whether you use a single or two turbos to get either result. One of the fastest GTRs in the world around a track will be going from a 9180 to 120lb/min of high mount twins so look forward to seeing how that comes together too

Yeah, pretty sure we've all discussed this before - though it doesn't really fix the room for dump pipes, intake piping etc however it seems some people have got reasonable setups in there which may allow the turbos all the breathing they need. The other trick with dual plenums (or twin turbos in general) is if you really are doing things properly and carefully, you probably should have separate load calculations done for each set of cylinders with it's own turbo. @AdapTronic 's Modular ECU supports tuning separate banks where dual plenums are involved, dealing with the fact that even with a seemingly symmetrical mechanical setup will result in the two banks having different flow and different boost characteristics... which is potentially being a significantly bigger trap (which is more often overlooked) for making a tune which doesn't suit the engine perfectly than the typical concern people have tuning RBs where they give a little extra fuel to certain cylinders. Yeah absolutely, I wasn't saying that 3.2litre at 11,000rpm is the same as a 2.2 at 11,000rpm - though perhaps I got a bit hung up on the idea that 6500rpm is a lot of rpm when it's about the equivalent to a 3.2 at 4500rpm. The concept I was getting at still applies, though - if you have a setup where the 9180 is rolling over at 7500rpm, a pair of 7163s might give you a fairly decent amount more usable rpm with less of a cost at low rpm. So laggier, but the amount of torque spread at the higher end more than makes it up - you just shift you rpm range to the right a bit. No issue on the inlet side in which setup? I believe there is an issue with the inlets on low mount twins on an RB, but definitely not with a single on a V6 - totally agreed with the exhaust being the big issue with a V6 single turbo setup, different problems but similar end result where a turbo doesn't perform as well as it could with a different environment. Yeah gotta say, a serious full house 3.2litre with a pair of 7163s would be very interesting to see - the potential is strong if they can be made to work in unison with each other than the engine at the higher end of their power potential. The way I view it however is that it's the equivalent to going to a bigger turbo setup that suits the higher needs better, a bit later in the rpm but potentially has a slightly better cost vs reward... which is often the case when you end up with a parts match that better suits the target. It's not so simple as "one size fits all".

Sorry I should clarify here, I am all for twin turbos on V6s - which is is a completely different engine bay configuration to a straight 6. With a straight 6, twins have to be kept on one side of the engine so they end up tripping over each other's plumbing as well as other things that need to occupy engine bay space - there seems to almost always end up being compromises made which could negatively affect the performance of the turbochargers... which may otherwise be capable of better performance. With a V, a single turbo needs to be fed by exhaust gases from sets of exhaust ports facing in opposite directions on the opposite sides of a V - ending up with different, but still relevant compromises made in exhaust manifold and piping design over what would be ideal. It's easier to make an optimal single turbo setup on a straight 6, and it's easier to make an optimal twin turbo setup on a V6 - the results usually seem to reflect that in practice, from what I've seen so far. That aside, Indy cars spin to >11,000rpm so I'm not sure I'd refer to them and EFR7163s as a "low rpm" setup. Spinning a highly efficient 2.2litre engine to >11,000 sounds like a thing which could easily result in the EFR9180 choking the engine a bit, while I don't know at all for sure - it wouldn't surprise me too much if the gains, even if not power gains, are in adding width to the power band by holding power better at the higher rpm... not picking up more power at the basement, but "helping" at the lower end by allowing gearing/shift points which are better suited to the huge rpm they've built those motors to live in. If you have a comparison between an equivalent and a single "true split pulse" setup going through gears it would be really really interesting! Definitely all keen for data which can help back up, or justify re-assessing my opinions. It's all part of the mission to work out how to make things go better

Is the boost control issue sorted? Still looks a little on the lazier size

Interesting, more power seems like a no brainer - but you expect some improvement in response as well with the twins? I am assuming you're talking at least EFR6758 size? Please share results if you do it, if there is any "cake and eat it too" solution over the EFR9180 on an RB I'd be quite keen to see it - but I definitely don't have anywhere near the confidence that the twin kits will deliver to suggest someone change... but in data we trust.

Hi, sir... I found this thread doing a search and it is nice I was asked (as often happens) to try and match a nice turbo for a mates RB25 track car with some very specific requirements, ie ball bearing, within a limited budget, T3 open flanged and able to make around 450kw @ hubs on E85 on a Dynapack dyno. I did some crawling around and decided to pay more attention to the GTW3476R than I had really given it previously (Garrett took AGES to release flow data for them) and I was actually pretty blown away by the match that they give, at least on paper. They actually look like an awesome combination from that point of view. How have you found you found yours so far? Real world response etc fairly acceptable for the power you are making? Was that power figure "all in"? Cheers

"Since this first step is all about low-end torque and throttle response, I thought the HKS route would be the best option." Riiiiiightttt