Sunday, October 31, 2010

Black or White? Ultra Racing Front 4 Point Lower Arm Bar and Room Bar

These arrived together with my rear beam but I simply ran out of time. Besides I didn't really dig the white powder coating. White is about the worse colour for something meant for the bottom of a car and exposed to all the road grime, dust, dirt and anything else you can think of.

The lower arm bar is as its name implies, ties the front lower arms for a more rigid assembly. So why is rigidity so important? Well anything that flexes too much including a car's chassis, bushes, tyres, etc. becomes a sort of a spring by itself except that unlike a car's suspension system this spring is uncontrollable which is not good for handling. Per Mike Kojima "The lower control arms front mount in our car (N16/B15) hangs out in space unsupported. This causes the lower control arms to move under hard cornering load causing steering inaccuracy and tire contact patch loss."

The room bar is the bar linking both the B pillars behind the front seats and also serves to improve the car's chassis rigidity.

All Ultra Racing bars are made from steel as opposed to lighter aluminium. Ultra Racing claim via its website that all brackets are 4mm to 5mm steel while hollow steel tubes and oval tubes are 1.2mm to 1.6mm thickness. Ultra Racing also claim that as steel is stronger than aluminium for the same size and thickness and that in order for aluminium allow to be as strong as steel it has to be at least double the thickness thus the weight saving is not so apparent anymore. You be the judge but I know which material I would prefer if I had the choice. Let's just say that the top Japanese manufacturers such as Okuyama Motor Sports aka Carbing offer their bars with aluminium alternative.  

I have sent my Ultra Racing bars to be painted matt black and should get them back for installation in about a week. Stay tuned.

Friday, October 29, 2010

Clutch Hose Upgrade - Installed

I had my G Spec Performance braided clutch hose installed together with my rear beam and disc brakes. The clutch hose is meant for the QR25DE but fits the QG no worries. The only difference from stock is the longer length which is not a problem. Picture below of stock clutch hose.

The airbox had to be removed to facilitate installation of the clutch hose. Picture below of the installed braided clutch hose

A teflon hose with stainless outer braid is not as flexible as a rubber hose necessitating a longer length. And make sure you properly bleed the hydraulic clutch cylinder after changing the hose. My Motul RBF600 brake fluid also doubled up as clutch hydraulic fluid. I'm thinking of sending my stock clutch hose to an AN fittings and braided hose supplier for replication complete with aluminium alloy end fittings. Any takers?

Tuesday, October 26, 2010

Brake Upgrade Part 1 - Rear Disc Brakes and Beam Upgrade

Going fast is not only all about building horsepower. A car will also need to be able to stop as well if it is not to turn into a flying coffin. By some strange logic TC decided to equip the second or arguably the fastest Sentra variant in Bolehland with rear drum brakes. Drums are cheap to manufacture and the brake shoes are even cheaper. However they're mostly useless for hard and performance driving on something as big and heavy as the Slowtra. I decided to upgrade the rear brakes to disc brakes as the first part of my brake upgrade.

The rear beam on drum braked N16s do not come with the mounting bosses for the disc brake caliper so to upgrade to rear disc brakes one has to either try and weld the bosses on the beam itself or source for a used beam complete with rear disc brakes. I did try the third option which was to buy everything new but TC wanted to charged me in excess of three thousand smackers just for the beam alone and we haven't even started talking about the calipers, rotors, etc. Clearly going for a used beam is the only economical option. Oh and here's what you need for a rear disc brake upgrade:

1. Rear Beam from an N16 variant complete with disc brakes (caliper, brake rotor/disc, pads, brake hoses), axles, hubs, etc. The complete assembly. Even the dust boot on the drum is different from the disc brake so hardly anything cept the some bolts are reusable. I've decided to upgrade my brake hoses to PRO-RS items. Everything else is stock Nissan
2. Rear handbrake cables. The drum and disc brakes use different handbrake cables.
3. About 1 litre of brake fluid. I'm using Motul RBF600

It took me quite some time, ok more than 2 years in my case to finally find a decent condition rear beam.  Blame that on other life priorities. TCEAS in Bayan Baru did managed to source for me a beam two years back but that didn't really fit my grade. The calipers and pads are all stock items. No point going for performance items yet as I'm on stock front brakes and upgrading to rear pads with a higher coefficient friction will just spoil the braking balance. Besides I have part two, three, etc. to write :)

Pix below of my rear beam after unpacking. Even the service centre manager helped to unpack the goods. Thank You Sir! The beam has been repainted and likewise the calipers. I choosed silver for the calipers for the oem look. Don't really dig ricey red. The long dangling things are not "tentacles" but are the handbrake cables.

I also had my "works engineer" who sourced me the beam to upgrade the stock bushes on the beam trailing arms to Superpro items. Thank You Ah Tiong (Hoong Hooi Motorsport). Ah Tiong even painted the calipers when his regular painter declined due to "too much work". The stock bushes cannot be physically removed from the beam as its shell had to be reused for the Superpro. This means using a burner or welder to burn away the bush. The shell was then spot welded to the trailing arm and the Superpro bush fitted. Pix below of the Superpro rear beam trailing arm bush.

So why all the hassle on the bushes? Picture below of the stock rear bush tells the whole story.

The stock soft bush is great for NVH as it allows for lotsa movement in all planes but this detrimentally impacts handling during hard braking and side load (cornering). The Superpro minimizes this. There is also the harder 90 durometer Superpro bush if one aspires to build and all out race car like the Dog III. I'm using the standard variant part number SPF1942K. The harder variant is SPF1942-90K. If you're interested in the bushes please contact me.

It took most of the morning to remove the stock beam. The exhaust heat shield had to be removed to access the handbrake assembly.

The PRO-RS rear braided brake hose installed to the caliper first. The mech managed to install the hose at the wrong side despite clear labels marking which side and which end. Luckily I spotted the mistake.
These are the ABS sensors for the rear wheel. Since the Slowtra does not have ABS these were removed. Per my TCEAS technician my beam's JDM as these use a different sensor compared to the MYDM N16 Sentra. There are two sensors (one per side) and part of the cabling is secured via brackets to the beam trailing arm.

The sensor goes here if  you're curious. I just grabbed a socket wrench quickly to help the mech to remove.

Picture below showing the drum brake beam vs the disc brake beam

The disc brake beam actually has a larger diameter compared to the drum brake beam. 65mm vs 55mm. IMHO the disc brake is able to generate more load and stress to the beam hence the need for a stiffer and stronger beam .

Picture of below of the beam installed on the Slowtra together with brake hoses.

Rear caliper and rotor.

All MYDM N16 and USDM non-Brembo equipped B15 variants run a 258mm diameter X 10mm thick solid rotors with same pad shape and size. Rear caliper has a single piston of 33.96mm. Compare this to the drum with a 203.2mm inner diameter and 17.45mm single piston. Clearly my stock 7/8" master cylinder is maxed out! Luckily brake pedal travel is not compromised and pedal feel is excellent with the PRO-RS braided brake hoses. Took quite some time to properly bleed all the brakes as I also had my front brake hoses upgraded to PRO-RS items. These might not stay too long on my car though as I have other plans for my front brakes.

Here's how the rear disc brake looks behind the wheel. Took the entire day to install and bleed the brakes. I also installed my braided clutch hose and changed the Slowtra's engine oil and oil filter.

Driving back home the improvements were immediately very obvious. The rear end felt more firm and planted. The brakes were so much better in terms of feel. Better stopping power was also noticeable. I'm not done though. I have a DBA 4000 series rear disc on order which should be arriving from Down Under in January. Have not decided on what rear pads to use yet. There's plenty of choices avail from EBC to Hawk to Carbotech so no worries there. And why am I only talking rear brakes when an FF car requires 70-80% front braking action? What about the front brakes? My front brakes pads are on its last legs but I'm not changing coz I'm planning to revamp my entire front brake config. And I mean it. Please be patient for Part Two and Three. I promise it won't take two years :)

Saturday, October 23, 2010

The Cost of Inflation! PRO-RS Brake Hose Kit

I first bought the PRO-RS stainless steel teflon braided brakes lines in anticipation of a rear disk brake upgrade for the Slowtra bout 2.5 years ago. The brake lines were sold when the project stalled. I've since bought back the same hoses but the price has gone up by ~ 8%. All I can say is Ouch!

Anyway here are the latest pictures. Packaging looks exactly the same as earlier.

Two of the hoses. These are for the rears.

The hoses look very well engineered. The centre tabs are for mounting and correct routing. Incorrect routing is often the most common cause of braided brake hoses rupturing or breaking into two as the hose will rub against the shocks or wheel rim eventually leading to wear of the hose outer braid, etc. and ultimately failure. PRO-RS braided brake hoses feature a stainless steel outer braid while the hose is teflon lined. Teflon is a material that has less flex and expansion compared to rubber thus eliminating the spongy brake pedal feel. The latest specification hose feature a transparent outer plastic sleeve which should help to better protect the hose from abrasion and dirt. Each hose is labeled for correct location of mounting. Excellent feature I must say as this eliminates the blur mechanic installing the hose in an incorrect location problem

Closeup of the end fitting. This end fitting goes to the brake pipe/line on the car. The other end is a regular banjo and mounts to the caliper. PRO-RS claims that its end fittings are Trivalent chrome plating goes to further elaborate that Trivalent chrome provides a safer and environmentally acceptable alternative to traditional chroming process of Hexavalent chromium. It decreases health hazards from airbourne chromium. Waste treatment and disposal costs are reduced because the process uses no Hexavalent chromium, no additives with strong oxidants, and has an extremely low metal concentration which is up to 95 percent lower than Hexavalent chromium. To my eyes the plating looks better than traditional cadmium plating and looks similar to the plating used on my G Spec Performance clutch hose.

IMHO from previous experience this is really one of the best bang for buck mods you can do for your brakes. Highly recommended. Oh and why did I buy the PRO-RS braided brake hoses? Well my rear beam + disk brakes and other yummy mods have already arrived as I type this post.