Why Twin Turb?
#51
The Ancient
#52
Built Not Bought
iTrader: (14)
It's an Eaton M62 positive displacement with electronic clutch which is from a Mercedes SLK 230.
Regarding finishing it. I have a 20b and I have a bone stock FD that needs an engine. So I'm torn between which car to put the 20b in. I could put the 20b in the twincharged car and use its motor in the stock car. Or make the stock car. 20b and complete the twincharged car as it is today.
Regarding finishing it. I have a 20b and I have a bone stock FD that needs an engine. So I'm torn between which car to put the 20b in. I could put the 20b in the twincharged car and use its motor in the stock car. Or make the stock car. 20b and complete the twincharged car as it is today.
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gmonsen (01-04-20)
#53
The Ancient
#54
Rotary Freak
Originally Posted by BLUE TII
We know from Indycar that they considered twin 6758 equal to one 9180 in power. I believe they switched 0.60AR to 0.85AR depending on course layout on the twin 6758s.
Indy car considered twin 7163 with 0.85AR an improvement in power over twin 6758 and single 9180 with a slight reduction in response over the 6758s with the 0.60AR
Indy car considered twin 7163 with 0.85AR an improvement in power over twin 6758 and single 9180 with a slight reduction in response over the 6758s with the 0.60AR
With the old Lancia S4, and the steam powered electronics used there, was expecting a turbo and supercharged car to be a certainty by the 90s....still waiting in vain!
#55
10000 RPM Lane
iTrader: (2)
well I'm not sure an Indy engine is comparable given 2.2L capacity, 12,000 rpm RL, narrow powerband, and only 1.6 Bar boost; then there's the mastery of developing a system that can operate between series to parallel flow paths but ok ...
also power level that was around 600 hp and through these turbo changes is now heading to 900 - 1000 hp soon.
also power level that was around 600 hp and through these turbo changes is now heading to 900 - 1000 hp soon.
#56
Rotary Motoring
iTrader: (9)
High rev 2.2L V6 is about as close as you are going to get ti rotary dynamics in the piston world...
The ID of the inlet on my efr 7163s is 2".
That is the old standard size for turbo runners that would taper or merge down to T4 divided flange.
Turblown efr manifolds are 1.5" ID and taper down to the T4 divided flange.
Put two 6758 or 8163 exhaust housings side by side and compare it to the T4 flanged divided efr exhaust housing and you can see why two of 7163 0.85AR exhaust housings even with their little 63mm exhaust wheels flow as much as a 83mm exhaust wheel in a 1.25AR housing.
which is two steps above the largest 80mm efr exhaust wheel in the largest 1.45AR efr exhaust housing.
The ID of the inlet on my efr 7163s is 2".
That is the old standard size for turbo runners that would taper or merge down to T4 divided flange.
Turblown efr manifolds are 1.5" ID and taper down to the T4 divided flange.
Put two 6758 or 8163 exhaust housings side by side and compare it to the T4 flanged divided efr exhaust housing and you can see why two of 7163 0.85AR exhaust housings even with their little 63mm exhaust wheels flow as much as a 83mm exhaust wheel in a 1.25AR housing.
which is two steps above the largest 80mm efr exhaust wheel in the largest 1.45AR efr exhaust housing.
#57
10000 RPM Lane
iTrader: (2)
I’ll concede on AR with some reservation. I had considered 2x phi swallowing capacity, but it didn’t seem to match up between some real world twin vs single comparisons. That may just be due to the flow dynamic of the smaller compressor. Which the 7163 compressor just doesn’t work due to the dynamic differences of the 13B at lower rpm unless you sacrifice with an electronic boost vs rpm scheme to keep out of surge for half the powerband. None of the other comparable EFRs for a twin fitment provide any relief of that. So for both fitment and functionality the S252SXE stands out imo. Which was only my point from the start.
I’ll give you a good deal on a new 7163 with all the options including an additional 90* compressor housing though
I’ll give you a good deal on a new 7163 with all the options including an additional 90* compressor housing though
#58
Rotary Motoring
iTrader: (9)
I already got a couple 7163s, just need a good deal on a pot of gold to work on the rest of the set-up.
I really dont think a 2 rotor could send a single 7163 into surge without antilag.
I would try it out with the T4 divided housing if you are looking for a badass 400ftlbs torque/350rwhp turbo.
#59
10000 RPM Lane
iTrader: (2)
There was a guy who put one on a Renesis 6-port RX8 and quickly went through several engines. It spooled almost immediately. He subsequently deleted everything he had online about it. It just depends what you’re shooting for. Nobody is going to try and get 30+ psi boost on a single, but dual in parallel is going to be in surge until around 5k -6k. 2.6PR is exceeded very quickly (19 lb/min) and the surge line is angled back sharply. S252SXE (7070) is already at 3.0PR by 18 lbs min.
if you layout a 13B like they did in this 2.0L thread post I think you’ll see what I mean
https://forums.vwvortex.com/showthre...#post111477498
if you layout a 13B like they did in this 2.0L thread post I think you’ll see what I mean
https://forums.vwvortex.com/showthre...#post111477498
#60
Rotary Enthusiast
iTrader: (8)
I haven't punted on weighing everything and since I don't have a hanging scale (or stripped REWs for that matter) I can't just pick up a 20B to get a gross weight from one I'd give a few individual weights. These are rounded to the nearest pound for ease of visualization, when I finish collating everything and throw it on a spreadsheet that I'll share you'll see everything to the nearest whatever it gets formatted to :P
Also the goal is a differential, not really to get ultra precise at the moment.
Part | 20B | REW
Eshaft | 25 | 14
Big Iron (includes gear) | 38 | 0
Intake Manifolds (Elbow to engine) | 31 | 21
Rear Iron (No gear) | 25 | 25
Center Iron | 26 | 26
Front Iron (No gear) | 24 | 24
Housings | 42 | 28
Rotors | 27 | 18
Total | 238 | 156
Diff | +82 | -82
Honestly this is a bit closer than I had thought it would be based purely on handling the parts individually and unfortunately I don't have a set of FD twins or a stock NA cast exhaust manifold to extrapolate what the exhaust side of both engines would be. That said I'm still very confident that an NA 20b in stock form would have been heavier from the factory than an REW as I dont believe the turbos, manifolds, and intercooler would weigh 82lbs + whatever the NA 20bs exhaust manifold would have weighed.
I could be completely full of **** and wrong though, I'm open to insight and please let me know if I'm forgetting anything of merit :P
Edit: I'm also aware that there are more parts that need to be weighed for a more accurate total such as tension bolts (20Bs with their extra thick set will fall further behind by a few lbs I estimate), gland nut (20b has a bigassed one), solenoids, waterpumps etc and I'm intentionally leaving off AC/PS and alternator.
Also the goal is a differential, not really to get ultra precise at the moment.
Part | 20B | REW
Eshaft | 25 | 14
Big Iron (includes gear) | 38 | 0
Intake Manifolds (Elbow to engine) | 31 | 21
Rear Iron (No gear) | 25 | 25
Center Iron | 26 | 26
Front Iron (No gear) | 24 | 24
Housings | 42 | 28
Rotors | 27 | 18
Total | 238 | 156
Diff | +82 | -82
Honestly this is a bit closer than I had thought it would be based purely on handling the parts individually and unfortunately I don't have a set of FD twins or a stock NA cast exhaust manifold to extrapolate what the exhaust side of both engines would be. That said I'm still very confident that an NA 20b in stock form would have been heavier from the factory than an REW as I dont believe the turbos, manifolds, and intercooler would weigh 82lbs + whatever the NA 20bs exhaust manifold would have weighed.
I could be completely full of **** and wrong though, I'm open to insight and please let me know if I'm forgetting anything of merit :P
Edit: I'm also aware that there are more parts that need to be weighed for a more accurate total such as tension bolts (20Bs with their extra thick set will fall further behind by a few lbs I estimate), gland nut (20b has a bigassed one), solenoids, waterpumps etc and I'm intentionally leaving off AC/PS and alternator.
Last edited by dguy; 01-06-20 at 05:56 PM.
#61
The Ancient
dguy... Thanks for weighing all that. Helpful. I think you discuss the difference nibbling at the edges so to speak. Let's assume the exhaust manifolds between the 13b and NA 20b are of equal weight. If that were true, then the weight of the twin turbos and the intercooler get subtracted from the 82 pound difference you came up with. That difference then will be about zero. And, through all of this discussion, it should be clear that my "custom" 20b is actually a bit lighter than the stock 13btt.
#62
Rotary Enthusiast
iTrader: (8)
dguy... Thanks for weighing all that. Helpful. I think you discuss the difference nibbling at the edges so to speak. Let's assume the exhaust manifolds between the 13b and NA 20b are of equal weight. If that were true, then the weight of the twin turbos and the intercooler get subtracted from the 82 pound difference you came up with. That difference then will be about zero. And, through all of this discussion, it should be clear that my "custom" 20b is actually a bit lighter than the stock 13btt.
I also wonder if they would have gone with a larger volume of substrate in the cat given the 33% increase in displacement and potential scrubbing required even under low load/speed.
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#65
The Ancient
jpfd3s... You're absolutely right. I had presumed that they would not have needed the same type of manifold or downpipe for an NA motor as for the TT 20b as installed.
Okay. Okay, guys... Disregarding the manifolds and downpipes and whatever, but taking dguys weights for most things having a difference of 82 pounds and subtracting 32 pounds for the twins and 10 pounds (?) for the intercooler, that basic weight difference would be 40 pounds plus whatever differences there are in the exhaust manifolds (and whatever else). Whatever the difference ends up being I think any "modest" weight gain would have been worth it then and now. If the installed NA 20b would have added 100-150 pounds, but made 300 hp, had slightly better performance, and been far more reliable, it would have been a better decision in my opinion.
Truth is that, while I have a strong view on all this, I just wanted to build an NA 20b and have the car weigh what it did with the stock twins and did that.
Okay. Okay, guys... Disregarding the manifolds and downpipes and whatever, but taking dguys weights for most things having a difference of 82 pounds and subtracting 32 pounds for the twins and 10 pounds (?) for the intercooler, that basic weight difference would be 40 pounds plus whatever differences there are in the exhaust manifolds (and whatever else). Whatever the difference ends up being I think any "modest" weight gain would have been worth it then and now. If the installed NA 20b would have added 100-150 pounds, but made 300 hp, had slightly better performance, and been far more reliable, it would have been a better decision in my opinion.
Truth is that, while I have a strong view on all this, I just wanted to build an NA 20b and have the car weigh what it did with the stock twins and did that.
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gmonsen (01-07-20)
#67
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+1, if i did another 20B it would be NA, the noise is worth it...
as a complete aside, my friend has a 20B Cosmo, and it is just awesome, however it is NOT a sports car and there is nothing about it that is lightweight.
as a complete aside, my friend has a 20B Cosmo, and it is just awesome, however it is NOT a sports car and there is nothing about it that is lightweight.
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gmonsen (01-08-20)
#68
The Ancient
#69
Rotary Enthusiast
Speedhunters recently featured a JC Cosmo at the Tokyo Auto Salon: Garage Yamaguchi's 20B-PP Mazda Cosmo - Speedhunters
I'd love to see more of them on the road here. There must be a modern transmission that can bolt to the 20B.
Also, could a variable-geometry turbo work with a new rotary engine?
https://www.carsguide.com.au/overste...y-turbos-68205
I'd love to see more of them on the road here. There must be a modern transmission that can bolt to the 20B.
Also, could a variable-geometry turbo work with a new rotary engine?
https://www.carsguide.com.au/overste...y-turbos-68205
Last edited by HiWire; 01-17-20 at 01:41 PM.
#70
The Ancient
Speedhunters recently featured a JC Cosmo at the Tokyo Auto Salon: Garage Yamaguchi's 20B-PP Mazda Cosmo - Speedhunters
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the funniest thing about the Cosmo, today is how small it is. its a big car in 1989, but in 2020 its teeny.
#72
The Ancient
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