As I tried to explain previously elsewhere, the entire thing is based on the BW EFR turbo line and attempting to use it to plot out any other turbo is a bit questionable. Because now as you can see, they’re not necessarily equal for a variety of design differences.

I was a believer for a long time in the thread on RX7Club ranking turbos on compressor and turbine wheel inducer/exducer diameters, but came to realize how that doesn’t necessarily relate to different wheel designs and how they actually flow, and now is pretty much blown out of the water when it comes to (at least some of) the G-series line.
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Well the ONLY thing that is different is the turbine flow rates .... once you know what those are , there is nothing else to upset the calcs. Compressor eff. is entered by hand so that isn't an issue either.

This at 13psi ..... def better than old turbo for spoolup which seems to be improving for some weird reason(3rd gear 12.5psi by 3500). Chart you are referencing was at 14plus psi I believe so more to come!
https://cimg6.ibsrv.net/gimg/www.rx8...a32c855beb.png

Boost is now pretty much flatlining so looks like the boost creep wont be a problem.

EMAP for virtual dyno run shown (12.5psi at blue line 3450rpm )

https://cimg9.ibsrv.net/gimg/www.rx8...d7d1b44ba4.png

Brett,
Exceptional results! :score:​​​​​​​ You keep outdoing ....ehh... yourself. :yelrotflm

IMV Mazda w/h sold a ton more 8's w/ anything near that performance...even given the additional cost.

Brett - When you remade the "log manifold" for the new V-Band turbo did you keep the rear rotor as a separate channel like the old one or is it now combined with the front and center channels?



https://cimg2.ibsrv.net/gimg/www.rx8...63af1c638b.png
Original split flow manifold

It's a single scroll housing but I did still install a divider to avoid any possibility of reversion.

came to the same conclusion for the same reason myself, but am waffling between waiting on the divided T4 or moving forward with the open v-band. The main issue at the moment is Garrett isn’t releasing the G25 housing dimensions like they did on all the planned G30 housing options per the flange diagram on their website. I suppose I might try to look at the equivalent older housing on the assumption it might be the same as you showed between your old vs new housings.

Boost is nice and stable at 15psi :
https://cimg1.ibsrv.net/gimg/www.rx8...e6a7679398.png

the higher it goes, the better it gets

let ‘er rip :suspect:
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Seems to be that way :) although I've reached the whp max already .

Might look at a high torque powerband ...muhaha!

Seems quite quick now ...16psi with 300plus lb/ft from 4000 to 7000

https://cimg2.ibsrv.net/gimg/www.rx8...a7a0fb3a04.png

Boost cut set to 7200
spooling to 16 psi 3rd gear by 3670rpm

https://cimg6.ibsrv.net/gimg/www.rx8...2ef27fac63.png

Exceptional results yet again Brett, commendable in every way! Just for curiosity sake, do you have a rough idea, maybe plus or minus %, that your VD lines up to with an actual dyno pull/graph? I've no doubt the VD graphs are within an acceptable margin compared to a dyno, but I'm curious if you've done any comparison (maybe with other cars) as to what that margin might be? I know there are so many more factors to consider than just the numbers a dyno spits out, but just curious on your experience between the two.

Regardless, here you are making me question my REW swap :lol:

Thanks RMRx, VD can be very accurate or it can be miles off ...there are a lot of factors that can throw it off (operator error being the main one) . I have managed to get with 5-10whp of the mainline dyno I use pretty consistently by using the same stretch of road (which runs slightly uphill) and doing my best to keep my runs at the same weight/ambient temp/ wind speed etc . Even then you can get rouge data points that can throw it off massively. With the logs I'm showing I have normalised those data points by straightening the rpm line to give a more realistic dyno.
So with the results I'm showing ...pretty damn accurate IMO. I've shown my VD results to the Mainline dyno operator after an actual dyno and he was pretty amazed.

Re the REW swap comparison . One of my original goals was to try and get parity with the REW engine. In the last few years however I've had to give up on that notion. The results we see with EFR turbos on those engines ... I can never hope to emulate. But the Renesis does have its good points and it's still worth it to explore the possibilities IMO.

Awesome, thanks for that info.... and I'm just being bitter because I haven't gotten to the bottom of my issues with the REW swap yet lol... it will get there, but for now I miss my BrettSpeed tuned, boosted Renesis!

Also worth mentioning is that VD is easily manipulated to give high numbers. Below is the same chart as above (that has zero rouge data points on it ) showing what happens if I cut it at 7200 (where boost cut is activated) . Shows a higher peak which may or may not be a valid number ... I wouldn't trust it personally. If there was a rouge result close to there it can skew the result even more ...I've seen over 500whp in some instances. So while i know it can be accurate ...it's still only a guide and real dyno results are way more trustworthy.

https://cimg9.ibsrv.net/gimg/www.rx8...0797a45cb7.png

well again, the turbine housing on there is equal to the one most people run on EFR8374, but your compressor is equal to an EFR7670.

in other words, an REW engine with EFR7670 and 1.2+ A/R turbine housing (if they made one that big for that turbo, which they don’t) likely wouldn’t look too much different

and again again, even the G30 0.83 A/R turbine housing outflows the EFR7670 0.92 A/R that most people use over there.

https://cimg6.ibsrv.net/gimg/www.rx8...f471961133.gif

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I think you are discounting the fact that the efr twin scroll turbo is the perfect match for an REW with a short twin scroll manifold!
We can't ever hope to achieve the same spoolup results on a Renesis ... but the G25/G30s are certainly a step in the right direction.

So what's your best guess for spoolup with the 0.83 AR ? I'm thinking 300-500rpm improvement which would see 16psi by 3200rpm at best . That still doesn't compare well with the good 8374 twinscroll setups I'm seeing on a regular basis.

It’s hard to be sure given your particular exhaust manifold design, but it has to be quite a bit better. I agree it will never be equal, just that it can be a lot closer imo.

I think there are a number of ways to get it a lot closer still with a Renesis, but would rather not go into that in this thread.

Well , I may end up putting the 0.83 on there to find out just how good it is . But the 1.01 with the EMAP I'm seeing is certainly giving me the confidence to push things to the limit on this turbo.
If I add more ethanol and push the rpm boost cut back further who knows ...maybe a 25psi monster will evolve :suspect:

https://cimg3.ibsrv.net/gimg/www.rx8...1d0289585.jpeg

:rollingla

curious to know if you’d make any changes to this based on your experience so far?

No, there would be nothing to gain going bigger and going smaller would put me outside the flow chart.

no silly rabbit, I meant the map layout :dunno:
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oh ..... a little . At 18psi I wont be holding it to 7500 , more like 7000 . So line will go along to 54ish lbs then down.

ok, seemed like you were operating below that line, but I’m making some assumptions that you likely have the actual data for ...

Yes ...so far the highest I've logged is 17psi and that chart was drawn to show 18. I'm considering staying where i'm at right now and leaving it till the actual dyno before turning it up further . Mainly from concern about breaking drivetrain components. The car is getting pretty damn savage at these boost levels.

supercharger
 

Brettus ; Hi Brettus, it's been a long time since we had a chat. You still make improvements in your RX8 project. I'm still using the DNA supercharger kit in my 2004 6 port rx8. It has worked well for many years with some improvements every winter.299 rwhp on a Dynapack at the most. But I wanted more power so 2017 I bought a new shortblock and geared up 18% to max SC speed 80000 @9000rpm by a larger crank pulley and a Gates RPM Racing v-belt 6 ribbed that doesn't slip. Made the RacingBeat groves in the waterjackets (35-40 hours work including building the devise to to make it possible). Limited revs to 8800rpm.and a wastegate to limit the boost to 0,65-0,68bar . Higher torque at lower rpms. and also ceramic apex seals from NRS Rotary,Sven Nilsen and nice pieces from Pineapple Racing. Started 2018 and got 314-316 HP @ max 0,65-0,68bar boost and got higher torque at lower rpm's, also very nice driving qualities. After 2500km on a trackday I had an engine crash . Rear rotor with ceramic apex ,half sideseal went away and middle iron+ rear iron + Rear rotor + rotorhouse. More than half of engine is totally distroyed.

Bought a new shortblock again 2020 and teared it down. Opened the exh port earlier by 3mm and polished all ports. Took the exh sleeves out (exiting work) to clean the irons from grinding metalparts also.

Now to the q about the side seal gap. I will use GOOPY Apex in this engine because the ceramics distroy so much when it happens.



What's your experience of side seal clearence when engine is boosted. I have searched and not found the figures for boosted engine. I realise that the seals grow in a higher engine temp under boost and to much clearence will make low compression. I haven't asked Rob@ pineapple Racing or Clive @ Racing Beat UK or Nandu @DNA yet.



This is a racing enthusiast born 1949



Rolf Östling





Sweden

Will reply via PM

well even at 18 psi, it’s still operating well below that line is my assessment

I suppose you don't to address it any more than the other thing; have it your way then. :)
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You are probably not taking into account the relatively restrictive intake on a low mount setup.

also:

if you mean the “restrictive intake on your particular low-mount design”, yeah, probably that and a few other things that might be particular to the way you’re doing it, in addition to RHD vs LHD differences. Just like I said several posts back:

Quote:

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Originally Posted by TeamRX8 (Post 4936044)

ok, seemed like you were operating below that line, but I’m making some assumptions that you likely have the actual data for ...

---

If that’s your position, then thanks for finally clarifying it. I suppose it’s good to validate that there are potential improvements to be made by people willing to eliminate those limitations.

Sure ... I made mine 3" and as free flowing as I could. It's not too bad but a filter straight off the turbo or a 4" intake ...is def. gunna flow better.

I don't think I've ever heard someone describe a renesis as "savage". This is crazy cool, hope it works out in the end.

Not sure when "the end" is . ........ I thought I was there 10 years ago ...lol

just throwing this out, re-imagine where you are now with a different turbo and consider the possibilities

the G35-900 is essentially an EFR8374 packaged in an EFR7670 envelope


https://cimg3.ibsrv.net/gimg/www.rx8...cf95dba32.jpeg

three things that come to mind :
1/ I'm not sure that I could get that to fit in a lowmount (comp cover is a LOT bigger than what I have).
2/ I'm not sure it would make anymore power than I already do ( whp ceiling is engine dependent not turbo-see '450' thread)
3/It won't spool as well as what I have.

It will fit, just not the way you’re doing it. It’s essentially a EFR7670 EWG size and a much larger/longer EFR9180 IWG fits between the engine block and the chassis.

Straight up, spool would be somewhat less due to the larger wheels and their increased MOI. Except it won’t be a straight up comparison since it can’t fit the way you’re doing it. Which is fundamentally in the most basic sense the configuration and positioning of the Greddy manifold with an EWG added; not exactly, but similar in a basic sense. How the two compare as a result of the different configuration and positioning is not so straightforward to discern prior to running it that way. My armchair opinion is that it can be improved.

Still not convinced on the other thing.
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I would not have designed it that way if there was more room to work with so sure it could be improved on.
Re the "other thing" ..... let's see what you can do!

There is more room to work with, you purposely chose not to make any more mods than you already did is all. It’s not a critique, it’s just what it is. I’ve brought some of it up in past discussions, but not everything that I think is possible.

The G35-900 has the exact same dimensions as the G30-700, just bigger wheels fitted into the same housing castings. Again, an EFR9180 IWG fits in there and it’s quite a bit larger in every direction. It’s just a matter of what’s required.


https://cimg4.ibsrv.net/gimg/www.rx8...7b1500956.jpeg


It only requires the necessary modifications, which I’ll just go ahead and say that imo some of the wall is using the original parts intended for NA use that aren’t necessarily a good choice for an FI Renesis application. The issue in general is the avg. RX8 turbo build is trying to do everything the cheap, and/or easy, and/or monkey see - monkey do way, rather than possibly looking for a better way. That’s a general statement not directed at any particular person. You’re obviously not the avg RX8 turbo builder, yet are kind of doing some of that too. The extreme opposite of it is the Landspeed RX8. There’s a lot of open middle ground between the two.

The thing is; as much money as you’ve obviously spent over the years, how much could have possibly been spent taking it in a different direction instead? Hind sight is always 20/20, so certainly not faulting you for that, but at the same time it pays to be observant of those who did what they did. I think we’re both sincere in our beliefs; it seems clear you sincerely believe doing those things is a dead end street due to the whp limit theory, but my sincere belief is that you may have boxed yourself into a blind corner and aren’t seeing a path out.

So I’ll just go ahead and say that my concept started as a street purpose, but am now rethinking it for a competition purpose, which requires shuffling things around from maximizing low end torque to instead maximizing work area under the powerband curve. I’m sure you likely understand more what that means than most of the other forum members will. What is likely not so clear is the path being envisioned to try and make it happen.
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Yes...some good points in there.
I definitely approached it from the point of view of not deviating too far from what was already there. My goals were more geared towards doing something that could be easily replicated by others and proving that you don't need an engine swap to make an awesome sportscar out of an rx8.
In that sense , I'm happy with the results and not too upset about the money I spent getting to here.

Virtual dyno @ 16psi
https://cimg2.ibsrv.net/gimg/www.rx8...a7a0fb3a04.png


Actual dyno at 15.5psi tapering down to 14.35 at peak (415whp@ 7563rpm):
Note : power is in WHP but torque is in NM (yes that is weird but it's just how they do it )
https://cimg7.ibsrv.net/gimg/www.rx8...46b30d29a7.jpg


The red line is pretty close to the virtual dyno but that was the first run and was cut short just so we could review logs . All the runs after that matched the green line. I'm thinking heat soak into the LIM is what is causing the lower numbers so currently have it apart again to do some better heat shielding.

Below are from top : EMAP , IMAP , AFR
https://cimg6.ibsrv.net/gimg/www.rx8...d3ad3c79c8.jpg


Below shows same info but cursor is on peak for the red line:
https://cimg6.ibsrv.net/gimg/www.rx8...19223a77c4.jpg


Didn't raise the boost as planned because I wasn't happy with the IAT logs ...more work to do there too :(

looking good brett

you're on e50 right brett? I wonder if leaning it out just a tad more could net more power?

Was on E40 ..... but yeah It lost some power when I added fuel ...not talking a lot though.

Well I'd say your VD is within an acceptable margin of error :lol:

Heh .... well on peak it's not too bad but at the wrong rpm and a bit optimistic everywhere else. Still ............... not far off at all.

Hey @Brettus, I'm curious since you've clearly done extensive research regarding your turbo selection, have you considered a Xona Rotor turbo? I'm looking at the XR 6564S specifically. Unfortunately, since Xona/Tial is a smaller company (unlike Garrett & BW), there aren't any compressor maps available. :(

XR 6564S X2C - Xona Rotor
Compressor: 58/79mm inducer/exducer
Turbine: 72/64mm inducer/exducer

Seems to me like a favorable turbine to compressor ratio, akin to @TeamRX8's assessment of how your setup is equivalent to an EFR7670 compressor & EFR8374 turbine. But hey, what do I know? lol
Looking forward to seeing how your build progresses!

Edit: Btw, has there been any porting done on your motor? Apologies if this has already been mentioned somewhere.

Brett,

I want to commend you for continuing to develop your ideas and spend time and money, and then post them here. You are doing real-world work, and I appreciate it. I am not a Renesis FI guy, (I own a turbo BMW with a very ancient and rudimentary kit installed), so the FI stuff is not high on my interest list, but I still read almost all of your posts. I know sometimes your ideas don't pan out, but you are curious, and you make your mistakes publicly, which takes courage. So thank you for providing so much information to the forum. And for not giving up on the Renesis.