Updated Again 01/18/08
There is a lot of misinformation floating around this forum concerning our suspensions. Perhaps this thread will help to dispel some of that erroneous information. I am no expert, I have very limited mechanical knowledge at best. Therefore, I only quote folks with considerable expertise concerning our suspensions. I provide plenty of links, facts, tech information, and expert, professional advice. Think of this as a collegiate level research paper on B13, B14 and B15 suspensions. Every source gets cited, as it should be.
I continuously keep this thread updated and current with any new offerings or information. Suggestions, corrections, or helping me with pertinent information or relevent photos is welcomed. "XXX" anything currently means I need more information or sources. I will incorporate things as rapidly as possible given my schedule. Typically new items show up every four (4) weeks or so.
If you find something I am missing that is pertinent to this thread, then by all means PM me. Or you can post it yourself in this thread, and (assuming you are on track) I will incorporate it into the thread body itself.
I *clearly* indicate where I may be guessing on a few items.
I hope you find this enlightening.
Shawn B
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Appendix:
I. Overview of the B13, B14, B15 Suspensions
* What is the differences between the three chassis codes?
* I want to get the rear beam on my B14, B15 bent.
* Why our suspensions are not easy to modify correctly.
* How Stuff Works link for those as ignorant as I am.
* Mike Kojima Lays The Information Smackdown
* Suspension component diagram and part numbers.
* Foreign websites, use the N14.
II. Conventional Struts and Springs
* Nissan OEM Stock Spring Rates
* SR20 Forum Exclusive Springs: Hypercoil and Road Magnet
* Other Springs: B+G, Dropzone, Eibach, H&R, Megan Racing, Progress, Tein, Tokico, Vogtland...
* KYB AGX struts
* Custom Shortened Koni's (abreviated to CSK's in this thread)
* Other struts...Tokico Blue, etc....
* Bumpstops
* Strut Boots
* Strut Mounts...OEM, Motivational
III. Coilover systems
* Advance Design and Ground Control
* B+G
* Bits N Peices
* Hot Bits
* Ksport (or D2's)
* Motivational Engineering
* Progress
* Shigspeed
* Shocktek
* Tein
IV. Bushings
* Energy Suspension - Downsides, "suspension bind", and do you really need them?
* Superpro
* Whiteline
* Spherical metal bushings
V. Braces
* FSTB options: Cusco, Courtesy, E-Bay, Nismo, Stillen, Whiteline
* Triangulated FSTB
* RSTB options: Active Tuning, Bolt In Bars, Cusco, IKEA brace, Whiteline
* Blehmco lower control arm brace
* NuTech lower control arm brace
* Progress lower control arm brace
* Whiteline lower control arm brace
* Traction bars
* Fender braces
* Foam filling the chassis
* Roll Bars and Roll Cages
* Harness Bars
VI. Sway Bars
* What the hell is a sway bar?
* Nissan OEM Stock Sway Bars
* Intrax
* Nismo
* NuTech
* Progress
* Suspension Techniques
* Whiteline
VII. Camber Kits
* What is camber?
* Camber bolts or "crash bolts"
* Cusco
* Ground Control
* Ingalls
* Stillen
VIII. A Few Words About Wheels & Tires
* How unsprung weight affects your car.
* How to do your own alignment.
* Conversion Tables for Rims and Tires.
* What size wheels and tires should I buy?
* Where should I buy tires?
* Stock OEM wheel information for the B13 and B14.
* How much tire and wheel can I stuff under my vehicle?
* Why in the hell are B14 OEM SE-R rims so damn popular on B13's?
XI. Limited Slip Differentials
* What is an LSD?
* JGY
* Nismo
* Nissan OEM
* Phantom Grip
* Quaife
X. Glossary of Suspension Terms
* Websites and links.
XI. Recommended Suspension Set-ups
A half-dozen basic recommended set-ups.
* What OEM parts do I need to replace?
* Daily Driver
* Daily Driver plus auto-cross/HPDE.
* Serious Racing? Never. You guys on on your own, you already know more than me. Uh....go look at the coilover section and leave me alone.
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I. OVERVIEW
What is the differences between the three chassis codes?
The B13 suspension is comprised of an independent McPherson strut suspension in both the front and rear.
The B14 and B15 suspension is comprised of an independent McPherson strut suspension in the front, and a solid rear beam.
Quote:
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Originally Posted by Choaderboy2
The B13/B14 front suspension is virtually identical. The B14 rear suspension works but has some inherent flaws, mostly a super high roll center. B14's require beam bending and a lot of rear roll stiffness to work.
When sussed out, B14's handle pretty good.
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98sr20ve drops knowledge on the B13 vs. B14 rear suspension:
http://www.sr20forum.com/showthread....uspension %22
Quote:
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Originally Posted by 98sr20ve
Beam= no bump steer, no toe adjustment stock, both tires always even with the road on smooth surface.
B13 IRS= bump steer, ability to follow the independent movement with both wheels, stock toe adjustment.
If you want a sweeping and overly simplified generality....
1) B13 better unless you can get the rear beam bent
2) B13 better slower speeds/b14 better fast speeds with a bent beam
3) B13 easier to setup for most people.
4) B13 better unless you can get the rear beam bent and then refer back to #2
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I want to get the rear beam on my B14, B15 bent.
98sr20ve (Steve) drops knowledge on bending the rear beam on a B14 to vastly improve the handling:
http://www.sr20forum.com/showthread....%22B14+beam%22
Why our suspensions are not easy to modify correctly.
Everyone wants to put a performance suspension on their car. It is a terrific first mod that paves the way for future modding. Going fast in a straight line is not nearly as fun as negotiating the curves. Having a ton of power is no good if you end up in a ditch. A performance suspension invariably includes a drop of some sort, and let's be honest, our cars look better a little lower than stock.
Lowering your B13/14/15 is a slightly tricky endevour. You cannot just "slam" a B13/14/15 on any old springs and struts and expect it to work correctly. The OEM B13/14/15 chassis has three (3) inches of suspension travel. When you start lowering the car, you can easily run out of suspension travel. Running out of suspension travel means bottoming out your struts, slamming off your bumpstops, possibly damaging the struts and/or losing control of your vehicle. Not exactly what you were looking for when you decided to buy a new performance suspension.
From:
Sticky on Sentra Lowering Springs! - NissanForums.com, this is what Mike Kojima has to say:
Quote:
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Originally Posted by Mike Kojima
A question that comes up every day thats annoying is lowering springs for the B13 and B14 Sentras.
These cars have very little wheel travel and cannot be lowered more than 1-1.5" without badly affecting the ride and handling. H&R spring are way too low and too soft, so are Eibach sportlines and even the less low prokits.
Get these only if you are into looks, the car will ride the snubbers in a turn and handle poorly. B14's have so little rear wheel travel that they will ride very bad as well. This is a rice mod.
The only lowering springs that are any good for B13 and B14's are the hypercos and they must be teamed up with a decent shock like a KYB AGX. They have decent spring rates and will really turn your car into a G machine.
Eibachs and H&R's will work well only when using Motivationals shortend struts and shocks for conventional shaped springs with Motivational/koni foam bumpstops and the Motivational rear shock mount for B14's. These will let you get your wheel travel back and even give a real nice ride.
Anyone asking these question over and over can now get flamed!
Mike
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More of Mikes wisdom from:
NissanPerformanceMag.com
Quote:
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Originally Posted by Mike Kojima, Nissan Performance Magazine
Article: Project Racer Suspension Upgrades
The NX has an independent McPherson strut suspension on all 4 corners. While this is a good thing, the NX suffers from a lack of wheel travel. When a car rolls in a turn, the suspension travel on the outside wheels is gobbled up by the roll. If the suspension bottoms out under roll, the spring rate will effectively become infinite and a disproportionate amount of weight will get transferred to that end of the car causing the tires to run at a large slip angle. This will cause the car to immediately slide at the end of the chassis that bottoms out first. This situation is so bad that trying to lower an NX/Sentra much more than 1" will result in bottoming under roll with any sort of reasonable spring rate.
Lowering a car to reduce the height of the center of gravity is one of the main things you can do to reduce weight transfer across that chassis to help keep load on all 4 wheels when cornering. Unfortunately the B13 platform does not tolerate lowering. So what can one do when building a race version of the car where we want to lower it at least 2 inch? The answer is a shortened strut. If the car is lowered by 2" and the strut is also shortened by the same amount, the center of gravity height can be significantly reduced while maintaining travel. This is the only way to really get a Sentra/NX of this era to handle well no matter what you have been told.
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Sport Compact Car had this to say:
Quote:
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Originally Posted by Sport Compact Car July 2000
Most people, no matter what we tell them to do, buy springs when they want to lower their car, but they don't change the shocks. At the same time, as shocks wear out, many people replace their worn-out shocks with stiffer aftermarket shocks without changing the springs. What this means is that aftermarket springs tend to be low, but not particularly stiff. If they were as stiff as they need to be to keep the suspension from bottoming out, they would be too stiff for stock shocks and, in most cases, even too stiff for off-the-shelf aftermarket shocks. The aftermarket shocks, of course, are too soft because people might use them with stock springs. Oh, the horror.
Componding this problem is the fact that Nissan almost always builds its cars with insufficient compression travel in the front suspension, so lowering the car means putting it perilously close to the bumpstops at all times....
With the SE-R, it seems, simple bolt on suspension work isn't going to cut it. So what's the solution?
Obviously the springs need to be stiffer to keep the shocks from bottoming out. The shocks also have to be stiffer to control the stronger springs. But above all, we need more compression travel. There are two ways to increase compression travel. First, the strut can be redesigned with a shorter shaft. This will increase compression travel and decrease droop travel. The other option for increased compression travel is to simply raise the upper mounting poinit of the front strut - a solution that would seem to involve major re-engineering of the body. (Author not credited)
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Quote:
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Originally Posted by Sport Compact Car April 2005
The B13 Sentra's fundamental suspension issue is travel. There isn't much of it. Lowering a B13 with conventional lowering springs has always led to disaster. Inevitably, the springs were designed to lower the car enough to please rice boys and were made soft enough for a cushy ride when paired with stock struts. This is the standard formula for aftermarket lowering springs and the reason we almost never put them on our project cars. Low and soft always gives you a bump stop-thumping street machine. (Author Dave Coleman)
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Quote:
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Originally Posted by Sport Compact Car July 2005
If the Classic has a fault anywhere, it's in the old chassis' suspension. In stock form, the B13 has little travel and horrible geometry. (Author Mike Kojima)
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Nissan Performance Magazine from this link:
NissanPerformanceMag.com
Quote:
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Originally Posted by Nissan Performance Magazine
The largest obstacle to tackle then was the lack of suspension travel on our B13 chassis. Most lowering springs have soft spring rates and they also reduce your amount of suspension travel. So, even though you're looking good, every time you hit a pothole or sudden change in the road surface you have to crank the wheel like a driver in a drift video. The really trick suspension setups correct this problem by using a shortened shock/strut body to increase the available amount of wheel travel. With these setups you can still lower your car for looks but more importantly improve your ride quality and handling characteristics. (Author Aaron Labeau)
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How Stuff Works -
Howstuffworks "How Car Suspensions Work"
This is for those, like me, that are mechanically ignorant. This link covers the basics of a modern suspension in general. Click and be enlightened.
Mike Kojima Lays The Information Smackdown - This is so good it is flat-out stunning:
http://www.sentra.net/tech/garage/suspension.php
NOTE: Understand that some information contained in that link is...dated. This article was written by Mike before Hyperco, let alone Road Magnet springs. Before half the coilovers in that section of this thread even existed. You have to view some of the information, specifically on commercially available springs (H&R, Eibach) and products (NuTech is out of business), in that article with a
historical perspective. However, all of the rest of the info is dead accurate today, still completely relevant, and it's freakin' brilliant. Read it all, twice.
B13 Suspension Components diagram and part numbers:
http://www.sr20forum.com/showthread.php?t=59815
Cross reference the N14 against B13 products. Check with your supplier.
Quote:
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Originally Posted by hpro123
And as in ALL "foreign" companies, check applications for N14 as well. They are identical. Some RNN14 are also identical, others are not.
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