Mopar Head Porting Templates' title='Mopar Head Porting Templates' />RB Techlt a hrefhttp www. Discovery Car Hirelt a EFFECTIVE RB head porting and flowtesting By far my most favored porting outcome is the GTR RB2. Its bigger bowl depth and superior as cast shape is a balltearer once ported correctly. On a full race port job i normally see well over 3. The exhaust also showing very hi air speed readings and a 7. My DWYER air speed pitot reads in thousandths of feet per second ,the rb. RB full port exhaust air speeds are well into 3. Flowbench inaccuracies calibration. Knowledgable engine builders porters will use there own flowbench as a back to back testing tool to record their readings and compare improvements and sometimes disprovements. A fool will run from shop to shop with his ported head comparing readings. Most flowbenches read different from bench to bench. Author Topic 383 432 Mopar stroker for the Challenger Read 20441 times. BBMheader3-1.jpg' alt='Mopar Head Porting Templates' title='Mopar Head Porting Templates' />I have calibrated my bench to the US edelbrock bench readings. This allows me to comparatively test against the US porters readings. RB porting outcomes,tuning,power. Porting outcome is dependant on the customers pocket as to how much can be done as it is charged out per hourly labor rate. The rb. 25 hydraulic heads, discerned by their short inlet long exhaust spring, are very popular as an entry level head but are limited in there useage. With a good portjob, our race hi lift springs and 2. Kilauea Mount Etna Mount Yasur Mount Nyiragongo and Nyamuragira Piton de la Fournaise Erta Ale. The rb. 25 NEO head shares the same port configure as the GTR RB2. GTR head. I personally prefer the GTR head for race application for its shim under bucket setup. The neo having a shim over bucket is succeptable to flipping out the shims under valve float situation. A correctly ported RB head of any style will make more power on the engine with any same said boost   eg. Recently porting an rb hydraulic head for a tunerbuilder after porting flowed 3. The whole combo was the same as previous except for the ported head, turbo, camtiming, compression all the same. On the dyno a 3. 7rwkw increase was seen from early boost right through. Something exceptional was the way it responded under boost with an earlier fatter power curve. The customers comments where it feels a huge increase below boost ,pulls harder through boost ,top end feels similar. INTERESTING he couldnt feel the top end bragging rights figure . The more power and torque the engine sees before the maximum top end figure is more crucial. This propels the car faster forwards and in any timed event we know what this means                                               RB power delivery,camshaft event, dynamic compression and valvefloat. Valvefloat is a serious problem which occurs in a turbocharged engine normally when boost is high. The valve spring is pushed open with the boost pushing against the back of the valve as its trying to close. Generally a spring requires the boost pressure added to its seat pressure setup to properly control the valve. In some circumstances intake plenum pressure seen at the valve can be more than the boost guage reads,dependant on blowoff valve setuptype and position. A faster opening ramp rate camshaft will require spring pressure adjustments depending on the rpm needed. As a rule of thumb factory cams with our upgrade springsetdropins will go 9. Resident Evil 4 Graphic Patch on this page. When using a 2. 72 profile with this ,same springs and boost, the rpm will need to drop to 8. The tell tale signs of valve float are a jagged top end dyno graph or a sharp dropoff in top end curve. The engine on the track shows no signs of valve float until later inspection of parts it is seen. Valve keeper recession in retainer, spring shim fretting, cam lobe unusual hi wear on the nose. Proper choice of parts with our experience will ensure no damage of engine internals. Camshaft dial in position is most important. Its very enjoyable on the dyno to move the cams around and see an earlier fatter dyno curve,, normally with some top end reduction,,,but this  will move the car forward QUICKER. Basically what is happening with cam positioning is the alteration of the engines dynamic compression. For example moving the cams in or increasing overlap will generally move the power higher and for a longer period of time, reducing the dynamic compression and opening up the engines breathing. Moving the cams out or decreasing overlap will generally drop off the top and bring the curve in quicker and fatter towards mid boost, closing up the engine or restricting its breathingpumping ability. All turbocharges and camshafts will respond slightly different but this is the general rule of thumb. Think of the engine as a forced air pump and moving cams is the tap controlling its pumping                                                                                     Darren Lewis. RB CRANK COLLAR FITTING. Our collars have precision ground internal bores which make it easy to gain the required. Crankshaft must be machined by an engine shop crankshaft grinder. Must be ground with a finish similar to a crank journal. Most crankshaft grinder operators are familiar with the precise measuring to gain the. The collar should never be fitted relying on the grub screws to hold it, with the correct. The grub screws are only to assure it not turning in event of pump lockup etc. Gently warm collar to a  light straw color and with a suitable mandrel knock the collar on very smartly. NOTE,  the heat soak from the collar will grab it very quickly so it must be a very fast knock on technique to assure it fitting home easily. Fit grub screws at journal end of collars at 1. We want to see our product fitted correctly so EMAIL with any questions. RB OIL PUMP FAILURES Every second phone call involves a discussion on RB pump failures. It is a dilemma that faces the unaware RB builder but can be addressed in several ways. Basically the 6 cylinder inline engine is not a balance friendly item to deal with at high rpm. The crankshaft harmonics through the inline 6 crank are inevitable and increase in magnitude as crankshaft stroke increases. This is no new engineering fact but has to be dealt with and manicured as per each individual combination and customers budget. The Nissan RB engine will go past or through its harmonic periods very quickly and this will interprate the success or the destruction of most combinations. Some turbocharger combinations will find a huge ammount of rpm per time and these are the oil pump killers. The cranks especially the long stroke RB3. We find in most race high rpm engines to stick with a 2. RB3. 0 to be limited to max rpm of 7. When using an RB3. The first sign of crank harmonics and too much rpm for a combination, is the loosening of the harmonic balancer bolt in operation. The bolt must be done up to 4. This cannot be achieved unless the flywheel or crank is held with appropriate tools. A knocking type hammer or torque wrench and car in gear WILL NOT achieve sufficient tension. The nissan gear tooth design is very weak and breakage will innherintly happen from tooth root to outer diameter in its thinnest area. The 2 flat internal gear drive flanks are also a weak driving design. Great for a stock engine as nissan designed it for but builders will find the flaws once modifying. Fixes for these issues are obviously in a race type application a conventional dry sump system. Some budgets and combos that do not allow will require an external wet sump style setup. Alternatively we can supply our moly billett gears which are successful in all 2. RB3. 0 limited to 7.