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I just thought I would give a heads up as to what I’ve been up to down here in sunny South Africa. As it turns out there are two types of QG18 engines here in SA, one is a UK spec Hatchback with NVTC (Nissan Variable Valve Timing) & an SA spec sedan with no NVTC, for info the current Australian Pulsar N16’s have NVTC as well as Fly By Wire Throttle. For a small country the aftermarket car scene is pretty big, not comparable to the US but not bad. The Nissan’s that rule the roost down here are the old SR20DE powered 200Sti’s (similar to the N14 Pulsar SSS) and SR20DET powered S14 200SX Coupes (Silvia’s). There is little or no interest in the Almera N16/B15 generation of cars, there are loads of them around but they have about nil street credentials as all the rental companies use them & most of them are QG16DE’s anyway. For the price its 118hp doesn’t really compare to the slightly more expensive options available here such as the Toyota RunX 1.8 Rsi (195hp), 206 2.0 Gti180 (180hp), Renault Clio 2.0 Sport (177hp) and Ford Focus 2.0 ST170 (170hp).
To try & keep up I have re-profiled the cams in my QG18DE Almera sedan. The profile is pretty mild and works well from low revs all the way to red line even though my engine doesn’t have NVTC. The profile is similer to a Schrick 250 profile but has a slightly smaller base circle. It was developed on a non NVTC engine so a much wilder cam can be run in a NVTC engine so there will generally be more gains. So far I haven’t had any wear issues on the cams, they were just reground & we found there was no reason to nitride them, as the hardening was deep enough.
The power measured on my standard 04 Almera was 61wkw (82whp) at 6100rpm. With custom branches (headers), a wet panel filter (locally made similar to K&N) & 57mm (2.25") mandrel bent exhaust & a Unichip piggy back ecu that went to 69wkw (92.8whp) at the same revs. Then with a mildly flowed head & re-profiled cams it went to 79wkw(106whp) @ 6500rpm. The figures may seem low but it was tested at high altitude as Johannesburg is almost 1830m (6,000 ft) above sea level & on average we have at least an 18% loss of power compared to figures achieved at the coast so theoretically the car should produce 93wkw (125whp) or almost 130kw (175hp) at the flywheel when tested at the coast. This is comparable to a standard SR20DE powered Sentra Sti which makes on average 73wkw at altitude & 86wkw at the coast (its rated at 105kw at the flywheel). So far my set-up has cost me about 1500US$, damn.
Obviously the cams weren't the only gain as the head was flowed as well but the car doesn't have a CAI, which would increase power further, but in general there could possibly be a gain of more than 10whp with a decent cam for the US cars if JWT do produce them. My engine currently has a very good torque curve pulling strongly from 3000rpm all the way to redline, my ECU is modified & currently I have the piggyback ECU controlling the rev limit still set at 6500rpm. If & when I get brave I’ll let it rev a bit more as the power is still climbing at max revs, from the power curve it could peak at about 7000 which could be worth about 5kw (7hp).
Possible future modifications include a custom centrifugal supercharger with an Intercooler that’s why I haven’t fitted a CAI yet; I don’t mind turbo’s but due to our hot, dry & thin air turbo’s spin a lot faster than at the coast to get to the same boost so reliability may be an issue, the best part about forced induction is there is very little power loss compared to the coast so boosted cars rule up here. Are any of you living in high altitude area’s & if so how has your reliability been with a Turbo. I know I need FI, I need to get into the 14’0s, my car is currently scratching to get into the 16’s. BTW as a comparison I went to the track this weekend & at this altitude the quarter mile for a standard Golf 5 GTI was 15.5s, a 350Z on street rubber was 15.0s, two BMW M3 CSL’s ran 14.4’s & 3 Vortech supercharged Z’s ran 14.0s, a 550hp GTR34 ran 12.8s & a Noble M12 ran 12.2s. A bit of boost goes a long way.
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