First introduced way back in 1979 the Jetta has had quite a few revisions over the years.
It was a similar size to the Golf and offered the budget concious executive an alternative to the more expensive larger cars.
Early models benefit greatly from tuning and looking at the options around for the Golf particularly the GTi you will get a wide selection of options.
The Jetta is badged as a Bora - especially in more recent years in most countries since 1998 so we will focus on the pre 1998 Jetta tuning options and leave the newer models to our Bora article.
Many Golf engine options were available in the Jetta line up. The Mark 2 in 1984 had a nice 1.8l engine although an engine swap to a more recent engine is usually your best bet. Our current best pic for your JettaTuning project is the 1.8T engine offering upto 180 bhp in standard form. With a remap and the upgraded KO4 turbo you will see power gains nearing 300-350bhp!
We have seen conversions which include the VR6 engine with a tuned output over 250bhp fitted to the 1992 model revison. The VR6 then is the best engine in the Jetta lineup for tuning, at least until better and newer engines came along. It certainly makes a great sound when it's being driven hard.
VW often skimped on the performance options compared to the more powerful Golfs options.So in all cases we suggest that you fit at least Golf GTi spec mods such as brakes. The suspension is also skewed towards a soft comfortable ride, we would recommend getting some adjustable shocks fitted and lowering the car by about 30mm but remember to get a Jetta Specific kit as the weight of the car is very different to the Golf.
The following modifications are usually performed by our members, decide how far you want to go before you begin.
Getting the right mods for your planned usage of the car is vital. Stage 3 (competition) mods just don't work well on the road.
Stage 1 mods: Exhaust, Panel air filter, Remap, lighter flywheel
Stage 2 mods: Ported and polished head, Fast road cam, fuel injector & fuel pump upgrades,power clutch
Stage 3 mods: Engine balancing, adding or upgrading forced induction (turbo/supercharger), Internal engine upgrades (pistons/head/valves), competition cam, sports gearbox.Whilst a lot of car part makers will claim peak BHP figures what you really need is a dyno plot showing the full torque curve. One of the most significant with the best cost to power gain, engine mods you can do is to fit a fast road cam. Don't forget to uprate the fuelling when you are increasing the power - it makes the car more thirsty. Using uprated injectors and a bigger capacity fuel pump deals with the fuelling issue.
VW Jetta intake and exhaust modifications.
Don't overlook the intake and exhaust. when it comes to car tuning as it is essential to get the cars breathing right.Derestricting the airflow into the engine is the primary part of tuning so get a better flowing air filter. Induction kits sound great with the induction roar they create but due to the warm air in the engine bay they will not add noticable power and actually rob you of power. Fitting a high flow sports exhausts will certainly help air flow through the engine but do not go too large or you will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results. See our article on performance exhausts for details of the issue around large bore exhausts and how to choose the right size for your engine.
Getting a professionally flowed head with larger valves can fully release the engines power. Your clutch can sap a lot of your power if it starts to slip and the standard clutches are only ever good for power gains of up to 40 or 50%. Fit a performance clutch to avoid power losses through the transmission. Turbo engines are just begging to be remapped. You will see big power gains on most turbo engined cars including diesels making a remap one of the most cost effective modifications.
The later diesel turbo engines have a lot to offer as well but for some reason the 1.9 TDi from the Golf GTi with 150bhp was not an option. All the larger powered diesel engines respond very well from a remap.
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