RB25DET Tech:

Q: What are the advantages of installing an RB25DET over an SR20DET?

A: The RB25 is stronger, produces more horsepower without mods, is smoother, and delivers more torque. This engine has a 2.5 L displacement, VTC (variable timing control) , 9:1 compression, and a factory ball bearing turbo. The power band on this engine is much broader. The SR20DET feels like an on off switch as compared to the linear power of the RB25. As much as we love the SR20DET, there is no comparison in torque. Lastly, the RB25DET bottom end and transmission are much better suited for high horsepower applications. Think of it as a step up from an S-15 SR20DET.

Q: On average, how much will it cost if I do the conversion myself using your kit?

A: The cost depends on how you want to set things up and how cheap you can get the parts. To do things right, we'd recommend the following:

-SYKO Performance conversion kit
-SYKO Performance wiring service
-www.driveshaftshop.com one piece driveshaft
-Greddy intake manifold
-Front mount intercooler,
-FAL electric fans
-Aftermarket air filter
-Z32 fuel filter
-External power steering cooler (small auto trans. cooler works)
-High volume fuel pump
-Adjustable fuel pressure regulator
-S14 or aftermarket (Griffin or Fluidyne) radiator
-Misc. hoses, belts, fluids, etc.
On average, including the cost of a clip or a motor set with cross member, retail price on these parts should average about $6,500 to $7,000. When you consider how this setup can net you close to 300 HP, it is quite comparable to the cost of building a reliable 300HP SR20DET.

If you don't want to spend this much, you can do without the FMIC, Greddy intake, etc..

Q: Is this engine conversion smog legal?

A: No, it is not. This kit was designed for off road use only.

Q: Does the extra weight of the engine affect the handling?

A: In our opinion...No. We've been running an RB 25 powered S14 on the track for 5 years and we have no complaints in the cornering department. With minor adjustments to the tuning of the suspension, our car handles great. Keep in mind that our kit lowers the engine and sets it back for a lower center of gravity and better weight distribution. In addition, close to half the extra weight the RB25 carries is in the transmission. As this sits close to the center of the car, the front to rear weight distribution is not affected as much as people speculate. We've never found an RB owner who thinks it is a problem. It always seems to be someone who has never driven an RB powered car on a track that spreads these rumors.

Q: Do I need to cut up my car or pound out the firewall to install your kit?

A: No. Our kit is designed to fit without modifications to the firewall. However, in some cases, clearing about an 1/8" around the starter hump may be necessary. This can easily be done with a couple of taps from a hammer or with a pry bar. The only thing you need to cut are the holes to run your intercooler pipes through. This is no different than the holes needed to install an SR20DET.

Q: Why does the SYKO kit require the use of the R33 Skyline GTS-T cross member?

A: The mounting pads on the KA crossmember sit too far back to properly line up the RB. All other kits available use unattractive "angle iron" looking brackets (running front to rear) to mate the two. From a design perspective, this is less than ideal for handling the high levels of torque that the RB can produce. Not only does it put stress on the conversion brackets, but it also adds stress to the mounting point on the crossmember. In short, the brackets add leverage to the torque of the engine much like grabbing a longer breaker bar to loosen up a tight bolt.

Thus, the use of the factory R33 GTS-T crossmember is part of the solution. As the mounting pads on this crossmember align perfectly with the engine brackets it makes for a superior design. By adding our polyurethane conversion mounts, the engine is positioned lower for an improved center of gravity and further back for better weight distribution.

Q: Why do I need to use the installation kit as opposed to bolting the engine in using the factory R-33 parts?

A: While the engine can be bolted in by simply using the R33 crossmember, the factory rubber mounts situate the engine too high and too far forward. This does not give proper clearance for the hood or electric fans. Furthermore, the biggest issue is that the turbo exhaust elbow (O2 housing) will not clear the steering shaft. While many people use primitive methods to get around this (cutting and grinding) this can be a serious safety issue. The best solution we've found is to build a custom tubular exhaust elbow which gives substantial clearance to prevent the steering system from binding. Having peace of mind on the track makes it well worth spending the extra money to purchase our kit. Lastly, without our kit, you will need to fabricate a transmission bracket as well as a custom driveshaft. Paying a shop to do this for you would not be cost effective.

Q: What makes the design of the SYKO kit better than the others?

A: As stated above, we keep the original Nissan design-- making for a stronger more reliable installation. In addition, our lightweight parts remove weight from the front of the vehicle and address safety issues in the design of the kit. If that isn't enough to convince you, just chose it because it makes your install look a whole lot cleaner.

Our exhaust elbow design gives a full 3" of mandrel bent flow, while replacing the heavy stock restrictive cast iron unit. It is designed to work with any SR20DET downpipe which is very easy to source. It is constructed from thick 16 gauge 304 stainless steel and TIG welded together. And yes, even our flanges are made of stainless steel for a long rust-free life.

Our mounts are made with CNC machined aluminum plates embedded in high durometer polyurethane. Our unique dual stage design firmly holds the engine in place, yet does an amazing job of insulating the chassis from engine vibrations. Just look at how thick our polyurethane insulators are and compare it to what other companies offer. At the same time, compare the surface area of where our polyurethane bonds to the upper and lower plates. This area is critical as it is the weakest point in any polyurethane or rubber mount. When you add the benefits of our outer aluminum "cage" (which limits how much the polyurethane can stretch), you get a system that can handle extreme racing conditions as well as very high levels of torque.

We have recently seen some companies resort to using a bolt straight through a block of urethane mount design. Beware of this type of system. While a bolt can hold an engine in place, it also transfers engine vibrations straight through the bolt leading to similar problems seen with solid motor mounts. At Syko Performance, we use our "Enginuity" to find innovative solutions rather than back yard remedies. We firmly believe that you will find our products to be the best available based on overall design, construction, and materials used in manufacturing.

Q: Can I retain my power steering?

A: Yes, the power steering system can easily be retained. It only requires a simple modification on the return (low pressure) line. Our instructions can clearly guide you through this.

Q: Can I retain my air conditioning?

A: Yes, AC can be retained, but it requires modifying the lines. This requires the help of a qualified AC facility to modify the lines and recharge the system. We recommend having someone evacuate the Freon from the system prior to starting the swap. Often times the removed Freon can be recycled, saving you some money when it comes time to recharge the system. Also, we recommend saving the compressor line fittings from your clip as they may be needed to modify the lines.

Q: What do you recommend using for a cooling fan?

A: The system requires about 2500 CFM airflow to cool properly. We recommend using the Flex-a-lite "Low Profile" fans as they are the thinnest we've found so far. With some modifications (removing the "FAL" aluminum disks behind the motors and grinding the shroud to fit tightly against the radiator), we've actually been able to mount twin Flex-a-lite fans (pullers) in conjunction with a stock S14 radiator. This is a very tight fit, but it can be done. If using a thicker aftermarket radiator, you will need to either ditch the pullers and opt for front mounting a pair of pushers, or notch out the radiator support and move the radiator forward. Another option is to mount a puller on the right side (behind the radiator) and a large pusher from the front.

As for radiators, chose a stock S14 KA radiator (thicker than S13) or go aftermarket aluminum. With these, we've had better results with the Griffin and Fluidyne than the Koyo. The Koyo is the thickest, which makes fan placement a bit more challenging.

Q: Do you offer wiring service?

A: Yes we do. Our wiring service is one of the best available. Utilizing our wiring service assures years of reliable service, "plug and play" connections, and a factory installed look. We don't just wire to get the car started. Our connections are soldered and sealed with heat shrink tubing, AFM and O2 wires are lengthened with shielded wire, and we take the extra time to make sure the ancillary circuits are connected.

We have studied the Nissan wiring circuits carefully and can assure that all our harnesses meet our high standards of performance. As we feel that conversion wiring is best left to professionals, please don't ask for "do it yourself" wiring information. We have spent countless hours studying each circuit and consider this to be a trade secret.

Q: If I use your kit, do I need to fabricate anything?

A: We are currently developing a front mount intercooler piping kit to be used in conjunction with the Greddy manifold. This will make the conversion a true bolt on. Until this is ready for market, you will need to fabricate your own piping. Other than that, everything should bolt up.

Q: What do I use for radiator and heater hoses?

A: You can use the factory Skyline RB25 radiator hoses. They need to be trimmed a little, but fit quite well. If you don't have them, please ask one of our dealers. We are asking them to keep these in stock. As for heater hoses, we suggest you go to your local parts house and piece something together. On the S13 chassis, you'll need to adapt the heater hoses from 5/8" to 3/4". On the S14 chassis, all components use 3/4" hoses.