N/A 20B motor
Thread Starter
Joined: Jun 2008
Posts: 5,859
Likes: 8
From: Los Angeles CA
N/A 20B motor
Do you guys think an N/A 3-rotor will be more reliable than a 2-rotor TT?
How would fuel consumption be different?
I've been told an N/A 20b would be more reliable than a piston engnie.
How would fuel consumption be different?
I've been told an N/A 20b would be more reliable than a piston engnie.
Thread Starter
Joined: Jun 2008
Posts: 5,859
Likes: 8
From: Los Angeles CA
Why aren't 20b N/A swaps more popular then? They produce a decent amount of power with alot more reliability. There is alot less reliability mods that have to be accounted for right?
Does anyone know anything about the gas mileage between a 2 and 3 rotor engine?
Does anyone know anything about the gas mileage between a 2 and 3 rotor engine?
Thread Starter
Joined: Jun 2008
Posts: 5,859
Likes: 8
From: Los Angeles CA
Yeah I've gotten quotes for an N/A swap and its MUCH cheaper than going non-N/A.
What is bump steer?
Knowing what we now know, can the 20b actually be more efficient than a TT 13b?
What is bump steer?
Knowing what we now know, can the 20b actually be more efficient than a TT 13b?
Joined: Mar 2001
Posts: 31,833
Likes: 3,232
From: https://www2.mazda.com/en/100th/
na 20b, will never match the mileage of a 13b. its 33% more engine to feel, more friction etc etc.
my 3 rotor running about 15:1 afr cruising on the freeway, would get about 20mpg (it was 19.9... 16 in mixed city/highway)
the fd 2 rotor stock, cruising between 3000-3150rpms will get about 24mpg.
3 rotor na is simpler, and should be dead reliable. with no intercooler, cooling becomes easier.
my 3 rotor running about 15:1 afr cruising on the freeway, would get about 20mpg (it was 19.9... 16 in mixed city/highway)
the fd 2 rotor stock, cruising between 3000-3150rpms will get about 24mpg.
3 rotor na is simpler, and should be dead reliable. with no intercooler, cooling becomes easier.
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http://en.wikipedia.org/wiki/Bump_Steer
Bump Steer
From Wikipedia, the free encyclopedia
Bump Steer is the term for the tendency of a wheel to steer as it moves upwards into jounce. It is typically measured in degrees per metre or degrees per foot.
On modern cars the front of the tire moves outwards, as the suspension is raised, a process known as the front wheels "toeing out". This gives roll understeer. The rear suspension is usually set up to minimise bump steer, where possible.
A typical value is two degrees per metre, or perhaps more, for the front wheels.
Excessive bump steer increases tire wear and makes the vehicle more difficult to handle on rough roads.
Solid axles generally have zero bump steer, but still have roll steer, in most cases. That is, if the wheels move upwards by the same amount, they tend not to steer.
Roll steer is an important part of the budget used to define a vehicle's understeer, known as a Bundorf analysis.
Difference between Bump Steer and Roll Steer
In a bump steer, both wheels rise together. In roll steer, one wheel rises as the other falls. Typically this produces more "toe in" on one wheel, and more "toe out" on the other, thus producing a steering effect. In a simple analysis you can just assume that the roll steer is the same as bump steer, but in practice things like the Sway bar geometry have an effect that modifies it.
Roll steer is usually measured in degrees of toe per degree of roll, but can also be measured in degrees of toe per metre of wheel travel.
Method of Adjustment
The linearity of the bump steer curve is important. If it is not straight then the length of the tie rod needs to be adjusted.
Bump steer can be made more toe out in jounce by lifting the rack or dropping the outer tie rod, if the rack is in front of the axle. The reverse applies if the rack is behind the axle. Usually only small adjustments (say 3mm) are required.
References
"Tires, Suspension and Handling" by John C Dixon
From Wikipedia, the free encyclopedia
Bump Steer is the term for the tendency of a wheel to steer as it moves upwards into jounce. It is typically measured in degrees per metre or degrees per foot.
On modern cars the front of the tire moves outwards, as the suspension is raised, a process known as the front wheels "toeing out". This gives roll understeer. The rear suspension is usually set up to minimise bump steer, where possible.
A typical value is two degrees per metre, or perhaps more, for the front wheels.
Excessive bump steer increases tire wear and makes the vehicle more difficult to handle on rough roads.
Solid axles generally have zero bump steer, but still have roll steer, in most cases. That is, if the wheels move upwards by the same amount, they tend not to steer.
Roll steer is an important part of the budget used to define a vehicle's understeer, known as a Bundorf analysis.
Difference between Bump Steer and Roll Steer
In a bump steer, both wheels rise together. In roll steer, one wheel rises as the other falls. Typically this produces more "toe in" on one wheel, and more "toe out" on the other, thus producing a steering effect. In a simple analysis you can just assume that the roll steer is the same as bump steer, but in practice things like the Sway bar geometry have an effect that modifies it.
Roll steer is usually measured in degrees of toe per degree of roll, but can also be measured in degrees of toe per metre of wheel travel.
Method of Adjustment
The linearity of the bump steer curve is important. If it is not straight then the length of the tie rod needs to be adjusted.
Bump steer can be made more toe out in jounce by lifting the rack or dropping the outer tie rod, if the rack is in front of the axle. The reverse applies if the rack is behind the axle. Usually only small adjustments (say 3mm) are required.
References
"Tires, Suspension and Handling" by John C Dixon
Never say never. Larger displacement doesn't mean the engine will always drink more fuel. You must take into account that the stock tranny is geared more for a less torquey 13b engine. Proper gear raitios would keep the cruising rpms lower and improve fuel economy on a 20b. Why do you think a 5.7L American v8 will get 28 highway mpg? Their highway rpms are around 2,000 rpm when crusing at 70mph. This is why I'm trying to find a suitable 6speed for my NA 20b with at least a .55-.60 6th gear ratio to drop the highway rpms.
Edit: Hmmmmmm after re-checking out IronMdnx's tranny thread that GTO 6speed transmission has the perfect gear ratios for the 20b and is stronger as well.
Last edited by t-von; Jul 7, 2008 at 10:57 PM.
Wasn't someone working on a T56 to put into a FD? Or am I dreaming. I remember reading it a while back.
Never say never. Larger displacement doesn't mean the engine will always drink more fuel. You must take into account that the stock tranny is geared more for a less torquey 13b engine. Proper gear raitios would keep the cruising rpms lower and improve fuel economy on a 20b. Why do you think a 5.7L American v8 will get 28 highway mpg? Their highway rpms are around 2,000 rpm when crusing at 70mph. This is why I'm trying to find a suitable 6speed for my NA 20b with at least a .55-.60 6th gear ratio to drop the highway rpms.
Edit: Hmmmmmm after re-checking out IronMdnx's tranny thread that GTO 6speed transmission has the perfect gear ratios for the 20b and is stronger as well.
Edit: Hmmmmmm after re-checking out IronMdnx's tranny thread that GTO 6speed transmission has the perfect gear ratios for the 20b and is stronger as well.
Joined: Mar 2001
Posts: 31,833
Likes: 3,232
From: https://www2.mazda.com/en/100th/
Never say never. Larger displacement doesn't mean the engine will always drink more fuel. You must take into account that the stock tranny is geared more for a less torquey 13b engine. Proper gear raitios would keep the cruising rpms lower and improve fuel economy on a 20b. Why do you think a 5.7L American v8 will get 28 highway mpg? Their highway rpms are around 2,000 rpm when crusing at 70mph. This is why I'm trying to find a suitable 6speed for my NA 20b with at least a .55-.60 6th gear ratio to drop the highway rpms.
Edit: Hmmmmmm after re-checking out IronMdnx's tranny thread that GTO 6speed transmission has the perfect gear ratios for the 20b and is stronger as well.
Edit: Hmmmmmm after re-checking out IronMdnx's tranny thread that GTO 6speed transmission has the perfect gear ratios for the 20b and is stronger as well.
