Slides

Is that a real quick 2-3 shift on factory gearing then 3-4 or was there a bump in 3rd?

rx7srbad

It was a bump in 3rd...as I rolled into a 3rd WOT then into 4th.

I recorded the run. I'll have to do a better job next time with the dragy gps overlay.

rx7srbad

17psi cleaned up..touch better. Firmly in the 6s range now!

What kind of power do you think is needed to run a 100-200 in the 6.5s range? Looking at auto top nl dragy gps data for 100-200kph this puts the rx7 with 17psi on the G35-1050 on par with a 2020 AMG GTR Pro/Huracan Evo for 100-200kph! both modern weapons with all bells and whistles and lightning fast boxes!

rx7srbad

The rattles are old interior plastics! 18 to 20psi testing remaining.

I tried testing at 18psi but had issues with boost control. Working to fix a vacuum leak...then will get back to it.

rx7srbad

To add some real world context to what a 6.58s valid 100-200kph means for a 30 year old rx7?

Lets have a look at the valid and verified dragy gps 100-200kph data collected by Auto Top Nl. These guys have tested some absolute weapons on their channel.

Take a closer look at the weapons(and HP levels) on this list with all the bells and whistles. Not a single manual in sight and all with lightning fast boxes for a seamless gear change.



Now lets objectively take a closer look at the time lost by the rx7 because of it manual box and me granny shifting not double clutching like I should. Yes i'm getting all the excuses out haha!!

Im calculating from 100% TP in 3rd back to 100% TP in 4th and the time taken to make that entire manual shift happen.
3.50.521 is the section time in 3rd gear at 100% throttle (moments later as the TP falls to 0%.)
3.51.056 is the section time in 4th gear back at 100% throttle.
Total Time lost to the manual shift - 0.535s

Take note, in 3rd Gear at 8102rpm 100% TP i'm at 17psi (full boost level i was testing at). However in 4th gear 100% TP I'm at only 6.1psi. Almost 11psi outside the 17psi full boost window I'm testing at.
So how much time does it take to get back to full boost of 17psi? Lets take a closer look at the data.
For me the section time is 3.52.829 to get back to exactly 17psi. Im at 100% TP in 4th 3.51.056 = 1.773s to get back into full boost window of 17psi.

In summary, 0.54s lost during the shift and a further 1.8s to get back into the full boost window. Isn't it great considering the time lost that the FD can still lay down a mega respectable 6.58s 100-200kph on pump fuel at only 17psi. I imagine with a DCT box which can shift up seamlessly within 0.1s and keep the turbo at max boost the FD (without increasing a single hp) would easily run a low 6s range all day long.

TeamRX8

iTrader: (2)

we’re talking ~62.2 mph - 124.4 mph for the metrically deficient crowd

that’s maybe starting around 5000 rpm or so in 3rd gear if you have the 4.11 rear gear. So the impact of an open housing on spool there is going to be minimal because I’m sure you’re rolling into it quite a bit earlier. It does impact the response on the 3-4 shift as you noted. I’d still suggest that it’ll be even faster with the 1.06 divided T4 because of the difference at the 3-4 shift.

We’d need more data to say for sure; weight, rear diff ratio, tire OD, but I’ going to estimate it’s in the ~550 whp range.

good job.
.

rx7srbad

Thanks, lets see if there are any improvements going up to 20 psi on pump fuel and wi.
Correct i'm rolling into 3rd around 3500rpm
weight - 1260kgs (full wet weight, full tank of fuel + driver (80kgs) = 1,340kgs. I've got no real weight reduction in my car....its full fat etc.
4.44 rx8 final drive
245 40 17 Michelin pilot sport 4 all around.

iceman4357

iTrader: (2)

looks fun and fast. Looks like its making great power(over 500rwp). With 4.44 and 245 street tires in the back, I cant believe you are not all over the place in 3rd. My old setup was right at 500rwp and I had to get a ET street tire with stock 4.10 just to keep the rear end from trying to come around on me.

rx7srbad

Fascinating, perhaps the 4.44 is helping my acceleration but not sure im at the 500rwhp level as I def have traction in 3rd and 4th. I can feel it going a bit twitchy sometimes but still stay in the run. The video feels flat, it doesn't do any justice to the real fear factor behind the wheel. Def gets my heart pounding! lol

Quite a few have mentioned I would need to run approx 30psi to run 500rwhp/600 at the flywheel with the street port on the G35 1050 (wrong turbine wheel). Im only at 17psi atm.

TeamRX8

iTrader: (2)

I was assessing it some off my own results in an 500+ whp REW-swapped RX8 which also has a 4.444. It weighs close to 3150-3200# with my postcovid fat-tush in it. I don’t have that range directly though. I had a 1-4 gear log, but the shift into 3rd is above 100 kmh but also a 3rd gear only log during the same session and then cut & pasted them together.

I was being generous some; had originally written 500-550 whp and thought that was maybe too wishy-washy. Which again there are a lot of factors involved. The G35-1050 1.21 is roughly equivalent to an EFR9280 1.05 wrt flow potential and depending on how much porting, how much intake restriction, how much exhaust restriction, how heavy etc. Some of those previous responses are possibly based more on a smaller turbo working a lot harder and less efficiently.

Because again, in general many are underestimating the Garrett G-series turbos by assessing them on size due to their past experience rather than the actual flow potential of the latest technical improvements.

I agree though, with that tire and rear gear it would likely be lighting them up pretty good at 500+. In reality your overall weight is most likely lower than mine which would translate to a lower output generating similar numbers.

.

rx7srbad

Wow for a G35 1050 1.21 to flow as much as the 9280 is impressive to say the least. I had no idea. I mean the g35 is tiny in comparison to anything 9280 level. I will put the car on a dyno power run when im done with the 18-20psi tuning so we get a real idea and some dyno numbers which can be correlated to their respective 100-200 kph times.

Yh these G series turbos are impressive. I had nothing but issues with my older to4z (couldn't even run into the 8s range with 16psi for the 100-200kph)....changed the turbo and the results (for me) have changed completely. Never thought i'd be posting up mid 6s range 100-200kph.

I am starting to see the turbine wheel restrictions on the top end now with the G35 1050 1.21 ar. Got the 4" dp and exhaust system going on next week which should really help but i imagine 22psi will be the G35 1050 maxxed out. Will be great to see what it can do 100-200kph at that boost.

What are your thoughts on the G45-1125? it has a 1mm smaller compressor compared to the G35 1050 but a ridiculous 82mm turbine (for all the exhaust flow) compared to the tiny 62mm turbine of the G35. Although the G35 has the mismatched turbine wheel for rotaries....the 100-200kph times it is consistently putting down is impressive.

TeamRX8

iTrader: (2)

my thoughts are you’re greatly mistaken on multiple levels

if there’s an issue then it’s more likely the configuration of your setup in one or more ways, at which point a bigger turbo is not going to help anything.

you should maybe consider putting it on a dyno first to determine what it’s actually doing, because 500 whp output would only be scratching the surface of that turbo/housing potential if true.

but that’s how it usually goes; it can’t possibly be the turbo manifold, or insufficient wastegate size/bias, insufficient intake flow/porting including the intercooler, and so on.

You can build almost everything for 650 whp, but if one or more critical points create a 500 whp chokepoint then that’s going be where the entire effort ends up regardless.
.

Howard Coleman

iTrader: (6)

congratulations!

for being out there w the right foot on the floor
for using a measurement to track results
for SHARING the process
for picking a new tech turbo
for picking my favorite brand of ECU

like any process into unknowns there are ups and downs but the learning moves forward.

the G35 1050 is an AMAZING new turbo because it is so small you can almost put it in your pocket..

and yet the compressor map is a monster.



looks like 100 pounds per minute out of this tiny frame. that's in the low 700 rw rotary hp range! out of a frame similar to the back in the day GT3582. Thank you Honeywell Aerospace Division.

you are currently doing business at 17 psi... that's 2.15 PRs. as you can see the compressor is capable of over 600 rotary rwhp (80 pounds per minute.) you are probably around just over 500 given your description of the drive....

that would place you approx 67 pounds on the map.

"Quite a few have mentioned I would need to run approx 30psi to run 500rwhp/600 at the flywheel with the street port on the G35 1050 (wrong turbine wheel)."

no.

the G35-900 has a 5.13 sq inch wheel while the G35-1050 has a really nice sized (6.42) wheel. you will be comfortably over 500 at 20 psi. and you (may) be there now at 17.

"fear" generally starts in the 500 neighborhood.

as TeamRX8 suggests, you are nowhere near the limits of hotside flow from the turbo. there are many other links in the chain and if one of them isn't solid the chain breaks and the turbo stalls.

if you are looking to assure yourself that the links in your chain are optimised as to efficient flow my list in order of importance is:

IC pressure drop. pressure sensors before and after core. you want less than 2 psi, i tested four cores last year. based on what i learned cores are at the top of the list.

turbo manifold. many manifolds have 1.89 I D runners. they are fairly good for about 400 rwhp. 50 mm/2 inches is the winner.

porting... the primary port should be the focus. it can be almost doubled

exhaust last on the list as long as you have a 3 inch with no restrictions. WG needs DP at a smooth angle.

you probably will be just fine when you crank up the boost.

we are very interested in what you learn on the dyno as well as what happens at higher boost. the best way to make more power is to turn up the boost while being conservative with timing.

again, congrats for doing something interesting and sharing.

j9fd3s

iTrader: (3)

Garretts Maps are in corrected numbers, and they have equations

17psi with a 2psi pressure drop is 2.29pr, add an air filter (0.5psi) and we are at 2.37.
80lbs a minute then corrects to 74.156 lbs a minute.

still a good place on the map!

for the turbine, we need preturbo backpressure, post turbo back pressure and EGT

TeamRX8

iTrader: (2)

it’s actually simpler than that once you understand what we’re discussing in the other thread

if I read correctly this engine is only mildly street ported(?). That’s going to be a limiter because otherwise the turbo will need to be pushed a lot harder i.e. increased backpressure, attempting to force flow through the straw. A larger turbo won’t resolve this.

spdracerUT

G40-1150 with the 0.95 A/R turbine housing will spool faster and make more power at lower boost than the G35-1050 w/ 1.21 A/R turbine housing due to higher overall turbo efficiency. The higher efficiency will reduce your EMAP, hence more power at lower boost.

TeamRX8

iTrader: (2)

the Rob Dahm FC project result says otherwise. In order for the G40 recommendation to work the flow through the engine needs to be improved significantly. Otherwise it’s just as I explained in the previous post, except in this case the G40 will be so low in it’s operating range there won’t be sufficient energy in the oversize turbine to drive it there and it will be backing up into the compressor intake instead. Just like on the Dahm FC engine and they only have the -900 compressor.

I’m referring to BP or Semi PP type port and modified exhaust port type flow. Because then it will all occur at lower boost pressure. If this engine has only a mild street port then we’re in the “trying to force 650 whp through a 350 whp straw” mode. Which with such a high flowing turbine wheel and housing is a far from ideal selection. The extreme far end of what I’m trying to convey here is a PP intake port, which anyone on here half way knowledgeable knows that it thrives on high flow with very low EMAP. That’s when the seemingly way too big turbo shines. You’re not making the connection on this for the restricted flow case though.

So I was only half joking/trolling at the time when I suggested in the other thread that you must be consulting Dahm on making their turbo selections for the FC and Vette projects, but am starting to conclude that I might be psychic . Because they’ve been trying to do it exactly the way you’re suggesting, but falling short of the mark. However, when they then suddenly added semi PP ports to the Vette engine along with changing from the 1.21 open turbine housing to the 1.06 div T4 housing then you can see exactly what I’m saying here and in that other thread. Because with the addition of semi PP and tighter housing then they had too much flow potential through the engine for the turbo being used; this same G35-1050, and now they need the G40-1150 to match up with that porting flow capability.

Which I’m thinking you haven’t seen my reply back to you last night in that other thread on this same scenario.

So again, without sufficient porting to allow the appropriate thru-put flow at the appropriate boost range, a bigger turbo is not going to help. It’s just going to be oversized for the application with the expected result of using a way too big turbo. The turbo selection along the porting have to match up. A 700 hp turbo combined with 500 hp port sizing is not going to provide the result being suggested.

When you match them up properly, you get a result like this, which is only a BW S369 SX-E 1.01, and only has large street porting with pretty good exhaust porting and thus required high boost and E85 fuel to force the flow through. This 80mm impeller & 1.01 housing used here chokes at 35 lb/min, or approx equivalent to where the G40 0.85 housing is at:

https://www.rx7club.com/single-turbo...19whp-1140159/

same exact engine/everything, but at 17 psi:

https://www.rx7club.com/single-turbo...17psi-1133866/


and then a PP 13B for reference comparison:

• 695hp at rear wheels at 17psi boost
• 555hp at rear wheels at 12psi boost
• HKS T51R turbo

Dyno graph for the 13B turbo - 695hp at the wheels using 17psi boost & E10 fuel.




I want to stress that it’s not my intention to be overly critical or intentionally mock you in any way. You obviously have a lot of FI experience and would likely walk circles around me in a reciprocating piston engine application and other areas as well, but wrt Mazda rotary wankel engines it seems like possibly a bit shy of a comprehensive understanding of these relationships.
.

spdracerUT

Porting on a rotary is analogous to cam duration, lift, and timing on a piston engine. It basically changes the VE of the engine changing the pressure ratio required to achieve the same power. Granted with modern piston engines, lift, timing, and duration are infinitely variable within a range while you obviously are stuck with fixed geometry porting on a rotary. Regardless, ported or not, the change in behavior in changing from one turbo to another will be the same. The main difference in turbo sizing for a rotary is that you REALLY want to keep the EMAP down as the apex seals do not tolerate knock. So you typically need to size the turbine wheel on the big side (diameter wise) relative to aftermarket turbos which tend to put too big of a compressor diameter for a given turbine diameter which negatively impacts blade speed ratio/turbine efficiency/overall turbo efficiency. People get away with it piston engine cars because they don't spit out pistons rings as quickly with detonation from excessive EMAP. Why do aftermarket turbos tend to stick too big of a compressor wheel for a given turbo? Because many people have the idea that bigger is always better. You want more power out of a turbo? Just put a bigger compressor on it! And ignore the turbine.... And that's how you end up with turbos that do make more power but with a lot more lag than if the turbine were properly sized too. If you go way back, like over 15 years ago, there use to be a Garrett GT3082 aftermarket turbo. You won't find a mismatched turbo in an OEM application because they do tons of simulation and then on-engine testing to hit very specific performance targets. The OEMs have to hit time-to-torque response targets and also fuel economy targets which means highly optimized high efficiency turbos. The G45 series is horribly mismatched as I've stated before. I think I've even said I don't like the G40-900 that much; I think they trimmed the compressor wheel down too far. It's basically like they put an inlet restrictor on the turbo which you can see in the top speed line dropping like a rock as the flow starts to choke. They would have been better off putting on a smaller diameter compressor wheel with a bigger trim.

For reference on G35-1050 performance vs the G40-1150, a builder I know working on a twin turbo Audi R8 with the V10 got these performance differences. G35-1050 in 1.01 A/R made 1500whp at 20psi; a pair of them of course on the V10. G40-1150 with the 0.85 A/R spooled faster and made 1580whp at 18psi because it has much better overall turbocharger efficiency. If you recall, the GTX3584RS was a bit of a dog (not that responsive for the power it made) because the turbine wasn't sized properly to match the compressor. The same is true of the G35-1050.

TeamRX8

iTrader: (2)

except that example has nothing to do with the situation we’re discussing, because in that example the G40 isn’t way out of it’s operating range on the turbine side

they made 350 whp (46.5 lb/min) at 21 psi (2.45 PR) with IAT exceeding 200°F(!!!). There’s nothing efficient occurring here because a turbo operating that far out of it’s operating range isn’t any where near it’s maximum efficiency range

let’s break that down, but just so we understand each other; I wouldn’t choose a G35, I was only saying for where that engine is operating it’d be better than a G40. My choice for 350 whp is a G30-660 with 1.06 div T4. What this shows you is that even the G30-660 wouldn’t be pushed hard at the noted power output. The emap is easily within proper bounds on the smaller turbo and in not just a more efficient position, but the response will be superior:



.


.



G40 turbine is grossly out of effective operating range
.



G30-660 1.06 is not in an undesirable emap operating range.



the people liking your post might be eating up your word salad rhetoric with a big smile on their face, only because they don’t know any better. In reality you have nothing to offer relative to the actual application at hand except words and reciprocating piston engine results that aren’t even the least bit in relation to what’s going on this particular 13B engine & turbo combination.
.
.

BLUE TII

iTrader: (9)

I dont know the situation/set-up beyond G40 on 2 rotor, but my 1st thought would be boost leak or obstruction in the intake tract post turbo.

rx7srbad

Gentlemen, some very fair points made. I'm no expert when it comes to turbo sizing/13b engine efficiency. Perhaps i'm being over critical of what i am seeing in my own mapping setup. The weather here has been terrible so I haven't had the chance to test 18psi/higher!

The 13b in question is a large extend/street port and the engine builder assures me its the largest street port he would be comfortable building.
The car is going in for the 4" dp and exhaust system tomorrow. I'll retest from 12-17psi again to determine if there is a real world performance gain here.

Will push up to 20 to 22 psi soon and see what the 100-200kph times reflect. goal is to keep it reliable and see what the dragy gps results show. This to me means more than dyno numbers...needs to be reliable and repeatable in the real world rather than a specific power number.

Was hoping to get some 1/4 mile testing in as well. lets see how things go!

Slides

Got a degree with honours in Mech eng or worked at National measurement institute near the top of the game in gas flow and near atmospheric gas pressure?

The turbo wasn't selected to remain on a near stock s4 motor in that specific case, even then (excluding you failing to account for pressure drops and filter loss) you actually demonstrated the G40 compressor at at least as good efficiency and the turbine not as close to choke, we are talking generally large extent to semi-PP range at AI/alcohol fuel applications for G40.

Noone is suggesting G40 as the go to for dead stock engine bays, you are making a fool of yourself claiming to be some kind of rotary magician.

TeamRX8

iTrader: (2)

not at all; a not so smart man never learns, a smart man might eventually learn, but a wise man learns from other people’s mistakes.

instead of focusing on education level, try being the wise man.
.

Slides

I want other people to be wise by taking Spdracer's advice not just you bagging him.

fendamonky

iTrader: (6)

Sorry man, every post you make comes off as arrogant and condescending. You're turning into a walking example of projection. Step back and humble yourself if you want to be raken seriously.