When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
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.
.
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.
Brett, Looking good...top end @ 10 psi ...very nice!
But the spool doesn't appear as good as with your previous set-up, i.e. 250 ftlbs @ 3750, and 290-ish ftlbs @ 4500.
What do you think ... more dialing in... or boost required; or hardware related?
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!
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 )
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?
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.
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
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.
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.
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.
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
01-08-2021, 08:31 PM
You keep outdoing ....ehh... yourself. 
although I've reached the whp max already .
