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why not quit playing the guessing game and get the car on a dyno?
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Unless it is the same dyno as someone else you are pissing in the wind anyway, no traceability in load cell, roller inertia or bearing drag and windage calculations. Everyone makes the joke about American miniature horses compared to dynodynamics and mainline for a reason.
why not quit playing the guessing game and get the car on a dyno?
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Its on the things to do list. I'll def get around to it based on my dragy gps data consistency.
Goal is to have 3 boost settings
low boost - low to mid 7s 100-200 (14-15psi testing looks promising)
mid boost - 6.5s 100-200 (17-18psi)
High boost - mid to high 5s. (??)
To summarize as the year comes to a close, I feel the 4" down pipe and exhaust system on my setup was a worthwhile upgrade. Looking at my own results on the previous setup 14 psi ran the 100-200kph in - 7.67s 15 psi ran the 100-200kph in - 7.38s Both already very respectable times compared to modern cars.
However, 1bar/14.5psi boost now runs a personal best for the 100-200kph sprint in 6.95s, which is a worth while gain.
Going up hill on the same setting. Fully optimized the G35-1050 on a street port is comfortably and consistently hitting low 7s to high 6s range at just 1bar boost. I was unable to achieve this pace previously. Looking at my data conservatively it is a gain of 0.27s in a manual car, which is significant considering i'm not running any additional boost.
Overall, I'm very pleased with the FD and the results this year.
Next year the plan is to visit SPA (Circuit de Spa-Francorchamps) on 19th October. The track day is already booked and perhaps drive to the Nurburgring after.
Also got a couple of Drag racing days booked at Santapod Raceway to see if i can setup the launch/boost by gear strat to hit those 10s 1/4m runs. Beyond that I'm already very pleased with the reliability of the overall package. Over 250 Dragy GPS pulls and still going strong. This may go on the fd at some point next year...to keep chasing dragy optimizations with the lowest boost threshold/max out the rpm range top end...see if power/tq holds to 8500rpm - 9k rpm. The G35-1050 may struggle top end but it has has performed miracles with hardly any boost being run through it which is very promising.
The slower progress on the 18+psi setting and above is a gremlin with my ignition system and also me being away on hols from Early December to Mid Jan which means progress wont take place until end of Jan/Early Feb. I really want to see what the G35 1050 can really do at 22-24psi.
Belated Merry Xmas and Happy New Year All. Hope to see more of you next year at the yearly U.K meet.
SPA, color me really jealous. i really enjoyed watching the F1 race at SPA which was the first time i looked carefully at the track. have you run there previously? how about Zandvoort?
BTW, a very brief look at the 35-1050 map looks like there is another 50/80 hp available with more boost. what is going on w your ignition?
looks good and is likely at or slightly more than mid-500ish whp ime
The only reason I had suggested putting it on a dyno is because it's the vehicle owner/thread starter who keeps asking for people to offer whp estimates based on the 100-200 kmh times being posted. We can opine all day long, but for a solid number it needs to be strapped down even though different dynos do output different values.
we can still get a feel for it from the acceleration data though; if you can pull it from the data, what’s the 160 - 200 kph time on your best run above? The 3-4 shift just prior to that skews assessment otherwise. Which 2 or so tenths difference in your times could be just the difference in shifting gears. Or if you have a 4th gear run only that will suffice.
also the manifold picture above indicates semi-pp ports. My expectation would be that the flow capability of semi-pp ports will max this turbo out before hitting the suggested peak rpm values. Bcause you don’t want this turbo to exceed the max compressor rpm limit on the far right of the compressor map.
That’s going to be beyond 700 whp flow capacity and you should maybe consider a higher capacity turbo and everything else needed to support it if that’s where you intend to go. Which would be a G40-1150 or G42C-1200, but obviously your call.
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SPA, color me really jealous. i really enjoyed watching the F1 race at SPA which was the first time i looked carefully at the track. have you run there previously? how about Zandvoort?
BTW, a very brief look at the 35-1050 map looks like there is another 50/80 hp available with more boost. what is going on w your ignition?
I've been to the race track twice but never had a running fd at spa. There is a long straight (kemmel straight) as you go up eau rouge...and with enough power its quite easy to break into the 200+mph range. I'd be happy to hit 150mph gps verified as I will be gearbox and 4.44 final drive limited but more importantly just lap the circuit a few times to tick it off my wishlist with reliability. It is a brilliant track. The few times i had been there, they had the 90s f1 NA race cars on track and classic cars on track.... what a mega experience.
Not sure getting ign break up at 18psi+, looked at the wiring before i left for hols, there was no relay in the ign harness. I'll need to add a relay and see if it solves the issue. I changed/ gapped plugs but made no difference.
No haven't been to Zandervoort but have played the track including SPA many times on the my racing sim.
Its a modest sim rig....not high end with motion or traction loss system which would be ideal! Fanatec DD2 V3 Pedals Porsche GT3 Podium Wheel, Formula V2 Wheel, forza wheel....got a few different selection of wheels. GT1 EVO cockpit Advanced paddle module
I've been practicing on Assetto Cora for spa on the sim rig to learn the track layout and the right gear selection for each corner/straight but like always the real thing will be very different. I'm running street michelin ps4 tyres which dont have the stiffest sidewall etc....but this trackday is more about fun than setting any lap records etc! If it get really invested, i may get some cup 2s....but it is october and it will likely be cold/damp/wet...so mp4 is probably a good gamble to drive there, complete track day and head to nur!
I believe Kostas has the fastest FD RX7 lap at spa. He's an instructor at the circuit as well. Hoping he may be at the track on 19th October with his rx7.
looks good and is likely at or slightly more than mid-500ish whp ime
The only reason I had suggested putting it on a dyno is because it's the vehicle owner/thread starter who keeps asking for people to offer whp estimates based on the 100-200 kmh times being posted. We can opine all day long, but for a solid number it needs to be strapped down even though different dynos do output different values.
we can still get a feel for it from the acceleration data though; if you can pull it from the data, what’s the 160 - 200 kph time on your best run above? The 3-4 shift just prior to that skews assessment otherwise. Which 2 or so tenths difference in your times could be just the difference in shifting gears. Or if you have a 4th gear run only that will suffice.
also the manifold picture above indicates semi-pp ports. My expectation would be that the flow capability of semi-pp ports will max this turbo out before hitting the suggested peak rpm values. Bcause you don’t want this turbo to exceed the max compressor rpm limit on the far right of the compressor map.
That’s going to be beyond 700 whp flow capacity and you should maybe consider a higher capacity turbo and everything else needed to support it if that’s where you intend to go. Which would be a G40-1150 or G42C-1200, but obviously your call.
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I will do a dyno power run soon. Hopefully first quarter of the year.
Good question, you can figure out the 160-200kph time from the 100-200 dragy data posted above for all the runs.
This was the best run so far at 17psi. So 6.58s - 3.58s = 3.0s 160-200kph time.
The low boost pb previously was 7.38s 100-200 at 15psi - 3.51s 160-200kph time.
The current low boost pb at 14.5psi is 6.95s 100-200 run - 3.09s 160-200kph time.
This shows a real world gain of 0.42s when conditions are ideal. (manual change eliminated!)
The same low boost run going uphill at 14.5psi ran a 7.11s 100-200 - 3.21s 160-200kph time
So when conditions are not ideal the gains are 0.3s. Think I mentioned (conservatively) a gain of upto 0.27s for the overall 100-200kph run.
Eliminating that gear change is showing a bigger real world performance gain of upto 0.3s - 0.4s depending on conditions. (For my application, in my findings confirmed by dragy gps data).
I haven't really done any single gear pulls as the performance metric i'm chasing is the overall consistency/repeatability of the 100-200kph runs so they can be compared against a whole arsenal of modern/performance cars. I think there's always going to be a +- 0.2s consistency issue with a manual car. No way to get around it unless you have a dct/auto box for the 100-200 runs. However, the dragy reports have enough data / breakpoints to eliminate the manual gear change if required and if it is of interest.
Its just a large extend street ported engine, the semi pp manifold will be swapped with my engine builders standard 4 barrel lim whenever the time comes. I'm not going semi pp or bport (yet). I'll see how the 35 1050 does at 20-24psi, all depends on the dragy data.
I understand it’s not semi-PP yet, but when you change to a semi-PP setup the G35-1050 is not likely going to have enough compressor to match the flow capacity at 8000+ rpm
that’s ~8 mph/sec acceleration in 4th gear on your 6.95 sec Dragy log, so yeah you’re definitely in the low-mid 500 whp range. This was from some logs I ran about a year ago:
pulled some other acceleration by gear rates out of the previous log:
assuming the car is likely over 3200 lbs w/driver, std. FD:RX8 5-spd, 4.444 R&P, 26.4” OD tire (255/50-16 MT E/T Street Drag unloaded) @ 18 psig air pressure
I understand it’s not semi-PP yet, but when you change to a semi-PP setup the G35-1050 is not likely going to have enough compressor to match the flow capacity at 8000+ rpm
that’s ~8 mph/sec acceleration in 4th gear on your 6.95 sec Dragy log, so yeah you’re definitely in the low-mid 500 whp range. This was from some logs I ran about a year ago:
That seems promising. Fantastic real world results for street use with only pump fuel at 14.5psi boost. I think the previous exhaust system with the 3" dp was perhaps not ideal. The 4"dp and full exhaust seems to have picked up some acceleration in the real world, which is great to see with good consistency on the dragy data.
Think Mr Dahm on his semi pp 35 1050 ran 600+ at 20psi or there abouts? least thats what the dyno said. I requested if he could do some 100-200 dragy runs. Hopefully he shares some data soon. Taking a closer look at the G40-1150 or G42 1200C if i go semi pp. Hopefully someone will post some results on these turbos with dragy data.
you need to study the compressor map better along with understanding what boost the turbo needs to be at to not be running out at low efficiency to achieve that reliably …
so again I don’t recommend semi-PP for 600 whp on this turbo, and not even really at all unless you’re shooting for 700+ but it needs a larger turbo for semi-PP regardless
an exception might be if you go with a smaller diameter; say 15 - 20mm rather than the standard full 30mm bore. I’m just pulling a rabbit out of my tailpipe guessing on that though.
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what’s the difference post-intercooler; negligible maybe like several degrees? 🤔. I suppose it depends, but there’s more to it than that operating across the bottom of the map.
the G40-1150 will accommodate it better regardless; lower or higher.
but particularly; those are only approximations and mostly based on the “oh my gaaaaaawd, OH MY GAAAAAAWD” youboob vids with a 1.06 turbine rather than the 1.21 here in this thread. I would actually expect it to be lower than indicated. In the one dyno vid at the very end whp was estimated to be around 740, but no way because it was actually a lot lower on the C-map than realized. Because on dyno vid 2 they were trying to dial it in around 600 whp, then suddenly switched to “we’re going to order a G40-1150” 🤔 , “but let’s just see what we can get down low by maxing it out”.
Which was 560 ft-lbs @ mid-4000 rpm range btw. Then claimed they maxed out the fuel system. So they had a 740 whp turbo on it, but not a fuel system to handle that? Go figure … 🤔 no, they maxed out the turbo then, but couldn’t get proper control of it previously when trying to tune it at the lower power level.
you see the thing about videos in general is they’re primarily visual and if you’re not really paying close attention and also not able to discern certain things then it’s not any different than magic shows, or pickpockets, (or forums too) etc. in that they create illusions and distract attention away from what’s really going on.
It’s like watching a cooking show and they’re making all these face gestures and talking it up about how good it smells and tastes. Yet for all you know it smells like dog farts and tastes like cat ****, but your mouth is still watering up just the same. And your watch is no longer on your wrist.
You might want to take the tinfoil hat off for a second and consider the Corvette was slapped together, blown up, rebuilt and they wanted to make it semi pp to try something new, then ran into fueling system limitations at the same time their priorities of testing the G40 became greater than maxxing out the G35.
Big numbers are unfortunately more interesting for 99% of the YT audience, which is important for Robs views -which is one of his biggest influences on what he tests. There's no conspiracy to hide power potential of a turbo or to put up a smoke and mirror show. Things are a lot less planned than you think.
You and I are the minority in wanting to see a proper foundation of fuel systems to test the response and maximum power potential out of a given turbo. I'm talking to Rob about back to backing and maxxing outthe G35-1050 and EFR 8374 on his semi pp engine, which would be better for road racing than the G40.
We will see how the G40 handles the extra flow of the semi pp engine, but it was too laggy on e85 for a street ported motor for road racing use.
I agree the g40-1100 has room to grow and bigger exhaust is better- if you dont mind the decrease in response over the smaller turbo.
Im visual myself and do like efficiency- I just have seen that big turbos at low boost make good #s on 2 rotors even when in inefficient area of the compressor map.
I’m not engaging in a pissing match in this thread with you guys again. Somebody used a G40 and it had too much lag for road racing, but no information otherwise on turbine AR or any other specs. Did I suggest they use a G40? This is a pump gas drag thread. Which goes back to the other things you want to incorrectly argue about.
Namely, the G35 1.21 turbine housing he has on there now with the G35-1050 maxes out at 35 lb/min flow. The smallest G40 0.84 turbine housing maxes out at 35 lb/min flow. You clearly don’t understand that relationship wrt 600 whp output on a 13B. My response to your tin hat comment is that your sphincter has such a tight grip around your throat that you can’t think straight due to a lack of oxygen.
I strongly suggest that the OP go back and watch those two dyno videos again in detail. If anyone else disagrees then fine.
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These threads are always worthless. If people have strong opinions, go do some back to back tests. I don't know if I've ever seen any one that said they would do it actually follow through though haha.
I’m not engaging in a pissing match in this thread with you guys again. Somebody used a G40 and it had too much lag for road racing, but no information otherwise on turbine AR or any other specs. Did I suggest they use a G40? This is a pump gas drag thread. Which goes back to the other things you want to incorrectly argue about.
Namely, the G35 1.21 turbine housing he has on there now with the G35-1050 maxes out at 35 lb/min flow. The smallest G40 0.84 turbine housing maxes out at 35 lb/min flow. You clearly don’t understand that relationship wrt 600 whp output on a 13B. My response to your tin hat comment is that your sphincter has such a tight grip around your throat that you can’t think straight due to a lack of oxygen.
I strongly suggest that the OP go back and watch those two dyno videos again in detail. If anyone else disagrees then fine.
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To elaborate on my previous statement of the G40 being too laggy for road racing on a street ported 13B: Robs FC has a mild street port, D-port exhaust, and the G40-900 with a .85 AR (the smallest G40) and I felt it was too laggy. It doesn't make 200lb-ft of torque until 3,600rpm and chokes pretty hard at 6,500rpm. I'm sure it will perform better once he puts a better IC setup on it.
I haven't driven the C5 yet with the G35-1050 with the 1.21 A/R, but that turbo looks amazing on the semi-pp engine. It makes 200lb-ft at an insanely low 2,900rpm!!! Then it made over 600whp from 7,300-8,000rpm, peaking out at 612whp at 7,850rpm before running out of fuel and dropping off hard at 8k rpm. This was 20psi on E85. The turbo also made 560lb-ft at 4,300rpm at 24psi before running out of fuel, which is also extremely impressive.
You pointed out that both of Rob's turbos (the FC & Vette) have the same 35lbs of exhaust flow. However, it was too laggy on the street ported FC due to the less exhaust volume from the engine turning a larger and heavier turbine wheel. Now the increased flow from the semi-pp motor on the Vette turning a lighter and smaller turbine wheel of the G35 made it super responsive with great low end torque, while being capable of 600+whp. It could probably make close to another 15-35whp with more injector or race fuel and/or water injection.
For road racing at lower power levels, the G35-900 (and/or a smaller AR) might be a better option for either the Vette or especially the FC (which is Rob's goal). It's also important to not fall out of boost on shifts for road racing or drag racing, as OP found out.
For the OP, Sometimes shifting at a higher rpm even though power is falling off will make the rpm in the next gear more favorable. This is easily determined by calculating and mapping the thrust curve of the engine (engine torque x gear ratios).
"It doesn't make 200lb-ft of torque until 3,600rpm"
it is interesting to me that you look at that. when i want to get an initial understanding about the "curve" i look at the RPM where the motor first makes 200 rwhp.
i also have an excel file of 87 dyno runs corrected to SAE with power between 5000 and 7500 at 500 intervals. each of the 5 power prints is totaled and the highest total wins the race.
12-04-22, 06:37 AM
