Engine/Turbo selection for Winding roads
#1
Engine/Turbo selection for Winding roads
I've been contemplating on the engine / turbo setup for roads like "Tail of the dragon" and "Angel Crest Hwy", basically tight medium speed winding roads with lots of 2nd, 3rd gear turns.
I am currently running stock port engine with stock twins at 14-15psi and it feels very good; I wonder if anyone has thoughts and or experience on making it even better with another engine/turbo configuration.
I have Ohlin DFV, STOPTECH BBK and nice sticky tires ... so running gear is good.
Looking for something a fast spooling, a little more low end tq and not necessary more HP.
Or am I looking at this all wrong and I should focus on weight reduction to increase enjoyment?
I have a 93 touring and have taken out the BOSE snake, installed RZ Recaros, 2 piece rotors, 17inch light weight RS wheels, titanium midpipe and catback ......
Next weight reduction step is probably with a Antigravity ATX-30D to replace my current AGM battery.
Thoughts?
I am currently running stock port engine with stock twins at 14-15psi and it feels very good; I wonder if anyone has thoughts and or experience on making it even better with another engine/turbo configuration.
I have Ohlin DFV, STOPTECH BBK and nice sticky tires ... so running gear is good.
Looking for something a fast spooling, a little more low end tq and not necessary more HP.
Or am I looking at this all wrong and I should focus on weight reduction to increase enjoyment?
I have a 93 touring and have taken out the BOSE snake, installed RZ Recaros, 2 piece rotors, 17inch light weight RS wheels, titanium midpipe and catback ......
Next weight reduction step is probably with a Antigravity ATX-30D to replace my current AGM battery.
Thoughts?
#2
half ass 2 or whole ass 1
iTrader: (114)
Stock is best. If you want more power then you can raise the boost some or get a different final drive to change the driving experience. Stock twins are going to be your best set up for this. An efr would likely do very well also but the cost vs what you're going for wouldn't make much sense. Stick with optimizing the twins. Go bnr if anything
#3
RX-7 Bad Ass
iTrader: (55)
For those roads you don't need/want big power. Twins and response are the way to go.
I have 99 twins and they can dig me out of a corner on the Dragon like crazy. I leave the car in 3rd all the way through the dragon, typically pulling out of a corner at 2200-2500 RPM and it digs in and goes.
If anything maybe look at the 99 twins, they have a lot better response. I also got the 4:44 RX-8 ring and pinion, that improves response big time as well.
Dale
I have 99 twins and they can dig me out of a corner on the Dragon like crazy. I leave the car in 3rd all the way through the dragon, typically pulling out of a corner at 2200-2500 RPM and it digs in and goes.
If anything maybe look at the 99 twins, they have a lot better response. I also got the 4:44 RX-8 ring and pinion, that improves response big time as well.
Dale
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gracer7-rx7 (10-04-21)
#5
Rotary Motoring
iTrader: (9)
S2 RX-8 4.77:1 differential gear swap will help whatever engine/turbo you decide on.
FD has some long gears and you can get caught up between them on slow corners.
I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.
The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.
If you decide you want the simplicity of a single turbo I would go EFR 7670.
FD has some long gears and you can get caught up between them on slow corners.
I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.
The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.
If you decide you want the simplicity of a single turbo I would go EFR 7670.
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gracer7-rx7 (10-04-21)
#6
S2 RX-8 4.77:1 differential gear swap will help whatever engine/turbo you decide on.
FD has some long gears and you can get caught up between them on slow corners.
I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.
The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.
If you decide you want the simplicity of a single turbo I would go EFR 7670.
FD has some long gears and you can get caught up between them on slow corners.
I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.
The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.
If you decide you want the simplicity of a single turbo I would go EFR 7670.
The set up makes sense on race track or nice pavements.
There is some times sand, gravel and other liquid/debris on the ground that makes it less than ideal.
Last edited by pd_day; 10-03-21 at 03:46 PM.
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gracer7-rx7 (10-04-21)
#9
Rotary Motoring
iTrader: (9)
Well, in my experience your front tires are going to hit the sand and gravel before the rear tires when driving your vehicle using the forward gears so sand and gravel are most likely going to make you understeer off the outside of the turn before it has a chance to get under the rear tire.
Im being serious and speaking from my experiences.
I put my car in plenty of ditches.
"Ditches love cars, so I gave that ditch a car." Is a saying with my group.
Now I mainly race sanctioned events.
Our autox venue is an old WWII diragible airport in the sand dunes and we been racing on it unimproved. Lots of gravel and sand there.
Im being serious and speaking from my experiences.
I put my car in plenty of ditches.
"Ditches love cars, so I gave that ditch a car." Is a saying with my group.
Now I mainly race sanctioned events.
Our autox venue is an old WWII diragible airport in the sand dunes and we been racing on it unimproved. Lots of gravel and sand there.
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scotty305 (10-05-21)
#10
Rotary Motoring
iTrader: (9)
The EFR 7670 was easy to modulate traction with for its HP. Much easier than my old T04B 60-1 turbo that made 40hp less and 100ftlbs less tq.
I think this was because of a couple reasons.
1) 7670 was very responsive and has the recirculating BOV back into the compressor anti-surge housing. You let off the gas a little and you dont lose all your boost and also, boost comes back right away.
So, your not doing the old flat foot steer through the wheelpspin driving like with a laggy turbo.
2) I had the boost cranked up with race gas so it was 420ftlbs tq and 420hp Dynojet. The fact that tq was equal to hp means torque took a **** at 5,000rpm. So, when the tires start to spin and engine rpms shoot up- torque dies off and its easier to modulate wheelspin.
But your point about increasing hp or tq not really helping in the curves is a valid point.
I had an auto RX-8 on Ohlins and the 18x11 295/30-18 DotRs from my FD and it would **** on the FD on a road where you cant use the gas and brakes. It just has higher cornering mph and you dont really care if it ends up in a ditch either (but, its an RX8, so it never did).
have you considered getting an RX-8 for the canyons?
I think this was because of a couple reasons.
1) 7670 was very responsive and has the recirculating BOV back into the compressor anti-surge housing. You let off the gas a little and you dont lose all your boost and also, boost comes back right away.
So, your not doing the old flat foot steer through the wheelpspin driving like with a laggy turbo.
2) I had the boost cranked up with race gas so it was 420ftlbs tq and 420hp Dynojet. The fact that tq was equal to hp means torque took a **** at 5,000rpm. So, when the tires start to spin and engine rpms shoot up- torque dies off and its easier to modulate wheelspin.
But your point about increasing hp or tq not really helping in the curves is a valid point.
I had an auto RX-8 on Ohlins and the 18x11 295/30-18 DotRs from my FD and it would **** on the FD on a road where you cant use the gas and brakes. It just has higher cornering mph and you dont really care if it ends up in a ditch either (but, its an RX8, so it never did).
have you considered getting an RX-8 for the canyons?
#11
Sponsor
iTrader: (41)
EFR 7670 is the ultimate replacement/upgrade for twins. It comes on fast and linear so you don't get the huge torque surge a modified twin turbo car can exhibit when the second turbo comes on which can put you into a wall. If you want more top end go with a 8374.
Last edited by IRPerformance; 10-05-21 at 09:20 AM.
#12
half ass 2 or whole ass 1
iTrader: (114)
Well he says hes just looking for a little more low end torque. The cost of going with an efr in pursuit of "a little more low end torque" isn't the assignment lol. Turbo, manifold, downpipe, intercooler, charge piping, fueling, ecu, tune.... imagine spending all that and all you needed to do was change your gearing 😕😕. Sounds like hes happy with the twins but just wants a little more on the bottom end.
#13
Rotor or no motor
iTrader: (24)
S2 RX-8 4.77:1 differential gear swap will help whatever engine/turbo you decide on.
FD has some long gears and you can get caught up between them on slow corners.
I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.
The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.
If you decide you want the simplicity of a single turbo I would go EFR 7670.
FD has some long gears and you can get caught up between them on slow corners.
I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.
The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.
If you decide you want the simplicity of a single turbo I would go EFR 7670.
#14
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actually Mazda USA has a ton of the whole assembly, RS08-27-100H, might be a better option, you'd need to swap it into the FD carrier (iron housing), but you'd get new bearings, gears, and the fancy back cover
Last edited by j9fd3s; 10-05-21 at 11:38 AM.
#15
RX-7 Bad Ass
iTrader: (55)
I think the 4.77:1 would be overkill for a street car. You'd be cruising on the highway at some ridiculous RPM. That would only make sense for a dedicated track car.
The 4.44's are in the sweet spot - they improve response but the car is still very street able. I get 22-23 mpg highway driving to Deal's Gap every year.
This also isn't the most crazy life-changing upgrade - you do it, the car seems more "eager" and can pull out at lower RPM's easier, that's about it. It's not like adding 50hp or something.
RX-8 diffs should be a dime a dozen, but parts for RX-8's are kind of weird now. Some of the parts people want a fortune for them and they aren't moving. RX-8's are dying off VERY quickly and I think a lot of them have been going to the scrap heap as-is, not even getting parted out.
Dale
The 4.44's are in the sweet spot - they improve response but the car is still very street able. I get 22-23 mpg highway driving to Deal's Gap every year.
This also isn't the most crazy life-changing upgrade - you do it, the car seems more "eager" and can pull out at lower RPM's easier, that's about it. It's not like adding 50hp or something.
RX-8 diffs should be a dime a dozen, but parts for RX-8's are kind of weird now. Some of the parts people want a fortune for them and they aren't moving. RX-8's are dying off VERY quickly and I think a lot of them have been going to the scrap heap as-is, not even getting parted out.
Dale
#16
half ass 2 or whole ass 1
iTrader: (114)
i have a 4.7 in my car and its as dale describes. ~4k at ~75mph is kind of annoying on the highway. i stay within a 30mi or so radius of its parking spot whenever i drive it so its never for very long but cruising is limited by rpm and i think that concept is wild. im sure i COULD cruise at a higher speed but sitting at 5k+ while doing it, im not interested
#17
Rotor or no motor
iTrader: (24)
Still available new. RS08-27-110A. its not cheap, but none of the ring and pinion sets are
actually Mazda USA has a ton of the whole assembly, RS08-27-100H, might be a better option, you'd need to swap it into the FD carrier (iron housing), but you'd get new bearings, gears, and the fancy back cover
actually Mazda USA has a ton of the whole assembly, RS08-27-100H, might be a better option, you'd need to swap it into the FD carrier (iron housing), but you'd get new bearings, gears, and the fancy back cover
i ended up buying a complete pumpkin from an R3 Rx8 to get the ring and pinion. not only they are expensive, they are hard to find
Last edited by R-R-Rx7; 10-05-21 at 01:23 PM.
#18
Rotor or no motor
iTrader: (24)
i have a 4.7 in my car and its as dale describes. ~4k at ~75mph is kind of annoying on the highway. i stay within a 30mi or so radius of its parking spot whenever i drive it so its never for very long but cruising is limited by rpm and i think that concept is wild. im sure i COULD cruise at a higher speed but sitting at 5k+ while doing it, im not interested
#19
I did find someone selling a 4.77 from a S2 RX8 for $480, looks like it might be a poor fit from being too short.
S1 RX8 diff can still be found readily available for $150-$200.
I somewhat want to go EFR 7670, but only if I can run it with a Petitt ECU. I am waiting for DJ to confirm, but I think he lost motivation.
S1 RX8 diff can still be found readily available for $150-$200.
I somewhat want to go EFR 7670, but only if I can run it with a Petitt ECU. I am waiting for DJ to confirm, but I think he lost motivation.
#21
10000 RPM Lane
iTrader: (2)
imo a 6-spd would make more sense than a 4.777, but obviously a bigger investment
surprised this latest NissanZ/CD009 conversion hasn’t come up on the forum yet, been out for 4 or 5 months now
which they also offer the trans and diff mounts for the ppf delete as well
https://www.fischracingtech.com/prod...adapter-system
requires using a Z based flywheel/clutch though is the only thing I consider a downside on it, offset by the dedicated cast bellhousing I suppose.
.
surprised this latest NissanZ/CD009 conversion hasn’t come up on the forum yet, been out for 4 or 5 months now
which they also offer the trans and diff mounts for the ppf delete as well
https://www.fischracingtech.com/prod...adapter-system
requires using a Z based flywheel/clutch though is the only thing I consider a downside on it, offset by the dedicated cast bellhousing I suppose.
.
Last edited by TeamRX8; 10-06-21 at 01:00 AM.
#23
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um Mazda would do the all of the above, if you can drop a little weight, add a little power (either hp, or gearing, at the wheels), and improve the suspension, you can make a big net difference
#24
Rotary Motoring
iTrader: (9)
This thread was about engine/turbo for tight winding road. I went into gearing as its related to power delivery.
If we are going into chassis set-up...
the biggest improvement in performance for tight widing roads/tracks (to the car) and also one of the most cost effective is wheels and tires.
I run 18x11 +45 wheels front and back with 285-305 wide DOT race tires.
Word of caution, higher cornering speeds mean wrecking at increased speeds as well.
Just having fun and performance be damned has its merits. *cough Miata*
If we are going into chassis set-up...
the biggest improvement in performance for tight widing roads/tracks (to the car) and also one of the most cost effective is wheels and tires.
I run 18x11 +45 wheels front and back with 285-305 wide DOT race tires.
Word of caution, higher cornering speeds mean wrecking at increased speeds as well.
Just having fun and performance be damned has its merits. *cough Miata*
#25
Wheels and tires are the first things I've optimized.
After multiple sets of rims and tires, I've settled on 18x10, 18x9 BBS LMs with 275 and 255 Firehawk Oval 500 tires.
Works great at a wide range of weather/temperature, enough traction going straight but can get loose in the corners and still have that "dancing" feeling in my hands.
As is sits
friends I’ve met on my midnight run
After multiple sets of rims and tires, I've settled on 18x10, 18x9 BBS LMs with 275 and 255 Firehawk Oval 500 tires.
Works great at a wide range of weather/temperature, enough traction going straight but can get loose in the corners and still have that "dancing" feeling in my hands.
As is sits
friends I’ve met on my midnight run
Last edited by pd_day; 10-06-21 at 04:17 PM.
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the_saint (10-08-21)
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