It's the sad truth that many car mod enthusiasts get taken for suckers every now and then. A louder exhaust, for example, is a mod that always gives you the feeling of more speed - but often it's not matched by the reality. New cams might give more power up top, but through the gears often the car can be in fact be slower... Certainly, it's rare for anyone to go out and quantify how much extra performance his or her mods have achieved. So imagine how impressed we were to hear that Melbourne's Access Auto Engineering had this trick-looking Nissan S15 Silvia (a customer's car) dyno'd after every individual power mod was executed. "Ahhh," we thought, "readers will surely get a lot of useful information outa the story behind this car." Sort of a S15 modifier's 'bible'.
So let's get down to it and fill you in on what Andy Chen of Access has done to his friend Remus Goh's 2001 Nissan Silvia...
Once the vehicle's factory-fitted SR20DET had been fully run in, the guys at Access drove it around the corner to BGT's Dyno Dynamics chassis dyno for a 'baseline' power pull. Running pump Premium Unleaded and the standard 0.85 Bar (12.5 psi) boost pressure, the rear tyres were turned to the tune of 120kW. Not too bad for a stock everyday SX - but, of course, not enough to negate the need for aftermarket add-ons.
Andy of Access says the first two mods for a S15 - or any vehicle in the Nissan S-line-up - should always be the intake and exhaust. Of course, this is pretty elementary stuff but in the case of the Nissan, the gains found with these simple changes are dramatic. The particular exhaust system fitted to Remus's yellow S15 was - at this stage - an A'PEXi N1, with a stainless steel mandrel dump pipe off the back of the turbo and high-flow 3-inch cat converter. Intake airflow was then enhanced thanks to an A'PEXi pod filter (in case you're wondering why it's all A'PEXi gear, Access Auto Engineering is an approved Australian distributor of the parts).
On Remus's car, these two mods saw power climb from 120 to a massive 142kW at the rear wheels. With just an exhaust and intake!
With the barely-touched SR20DET now pumping out around 18 percent more power, the guys fiddled with the turbo wastegate actuator for a tiny increase in boost - from 0.85 Bar up to 0.90 Bar (12.5 psi to just over 13 psi). It was bugger-all of a boost increase really - but the BGT Dyno Dynamics chassis dyno sure picked up a marked improvement. Just that extra whiff of psi it pulled another 6kW - sliding the tally up to 148kW at the wheels.
Obviously, the SR-engine was hangin' out for more boost.
Up until this point, Remus hadn't had to shell out all that much cash for his newfound grunt. However, the following mods gobbled up disproportionately more dosh. Next, an A'PEXi Power FC plug-in programmable ECU was entrusted to take over the control of the standard fuel and ignition systems. Incidentally, every car we've seen running a Power FC computer has started, idled and run absolutely beautifully. Not something that can be said for the majority of cars we see running aftermarket management....
So with the ability to tune more aggressively than Nissan Australia had decided to, the Power FC hand module was prodded until a full 10kW gain was seen at the back wheels. These air-fuel mixture and ignition timing changes bumped the max power figure up to 158kW.
Turbo boost control was next on the agenda, and Access came to the party with an A'PEXi (like you're surprised!) AVC-R electronic controller. Andy informed us he only likes to take a stock Nissan engine - such as this - to a safe maximum of 1.0 Bar (14.7 psi). This baby, however, was pushed a little further - to 1.2 Bar (17.6 psi).
This extra shot of boost encouraged a full 175kW at the rear tyres. Note that an A'PEXi blow-off valve was also inserted at this stage - though it made no difference to power because the standard item wasn't leaking.
As a high-boost safety precaution, Andy stressed to Remus that intercooling should be upgraded to suit a.s.a.p. So - before anything had enough time to go 'bang' - an A'PEXi GT-spec front-mount air-to-air 'cooler kit was slotted in behind the standard front bumper bar (which need to be modified just a little). The just-fitted blow-off valve also had to be relocated.
Oddly enough, the Dyno Dynamics chassis dynamometer revealed that the new intercooler gave zero increase in power. One-seventy-five kilowatts was all that they were gonna get from this particular combo (we're guessing largely due to the limitations of the standard turbo).
During the build-up process, Remus had graced his car with various eye-catching body mods (like the factory yellow paint isn't enough!) There's now a race-style carbon-fibre T-wing, A'PEXi stickers down the sides and across the bonnet and a tough-looking set of Volk Racing 17s. These are clad in 235 and 255 Falken rubbers, which fill out the guards nicely thanks to the lowered stance afforded by Tein adjustable coil-overs.
Inside there was little that needed doing. Complementing the factory Silvia trim is an aluminium shift knob, fire extinguisher, Alpine head unit and A'PEXi electronic boost gauge and turbo timer.
With the remaining total of 175kW at the back wheels, Andy was keen to see what sort of quarter mile times this relatively mild brace of mods equated to. Just before the run was made, however, the exhaust system was again altered - this time to a lightweight titanium system (which, Andy says, didn't affect power against the N1 pipe work).
So - at Melbourne's Calder Raceway and kickin' around in a pair of slick rear tyres - the S15 blasted over the beams in only 12.7 seconds.
After running that 12.7, the next logical mod was an up-sized turbocharger - but the guys were taking their time selecting which set-up would be the best for the street. After all, they'd grown to love the amount of power and response they'd gotten so far. As Andy says, all of their extra power had come at no expense to response, drivability or low-down torque. It really was a case of having it all.
But, unfortunately, the guys are no longer contemplating what sort of turbo to trial; just after our photo shoot, the Silvia got totalled. It spun into a roadside pole and it is no more.
Them's - literally - are the breaks....
Contact:
Access Auto Engineering
+61 3 9873 0133
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