Super Street Network

Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
 |   |   |  SEM Motorsports Intake Manifold - Upping The Velocity
Subscribe to the Free
Newsletter

SEM Motorsports Intake Manifold - Upping The Velocity

SEM Motorsports 1.8T Intake Manifold Upgrade

Dec 4, 2013

Key Features

  • Designed and constructed by SEM from A365-T6 aluminum and heat-treated
  • Plenum features 2.75L of internal volume for increased flow capacity to supply enough volume for higher rev limits
  • Shallow profile design maintains lower CG (center of gravity); will accommodate various 1.8T swaps
  • Large inside diameter and calculated runner length to support higher peak hp
  • Standard stock TB and 80mm TB-sized flange openings available (custom options available upon request)

SEM motorsports intake manifold upgrade cast aluminum Photo 2/7   |   Made of thick, high-quality cast aluminum, the SEM intake manifold is designed to optimize the powerband of the 1.8T engine and bolt in without any custom modifications.
SEM motorsports intake manifold upgrade stock vs SEM Photo 3/7   |   Thanks to a larger plenum design and integrated velocity stacks, SEM’s intake manifold provides a significant increase in air over the stock unit.

Test Mule

2003 Volkswagen Golf GTI 20th Anniversary

Engine 1.8L turbocharged 4-cylinder

Relevant Mods Unitronic Stage 2 software, SEM 3-inch Turboback exhaust with high- flow catalytic, AEM intake, AEM cold air

Description

The VW community isn’t exactly touted as a bunch of performance-driven enthusiasts. Instead, most focus on ride height and wheel fitment. However, that’s not to say there aren’t individuals out there looking to go fast and hungry for power mods. The GTI lineage of Golfs has proven to itself be a real contender from our German counterparts. And with a turbocharged engine, there’s plenty of room for improvement.

Intake manifold upgrades are usually seen as hard-core mods that are only done when engines are making big power and the stock unit is choking airflow. While this rings true in many cases, a properly designed intake manifold can actually be a worthwhile upgrade to any engine.

SEM Motorsports set out to build a manifold for the 1.8T that would improve flow and throttle response while gaining horsepower and torque throughout the entire rpm range. Cast from durable, lightweight, A365-T6, aluminum metal, the SEM intake manifold is designed to replace the stock 1.8T manifold with no modifications necessary.

The plenum features a 2.75L internal volume capacity, and combined with integrated velocity stacks, the increased airflow especially helps the upper rpm range where the stock intake manifold struggles to keep up.

SEM also put a lot of thought into fuel injector placement on the runners to ensure optimal fuel atomization into the combustion chamber. To ensure equal flow of both fuel and air into the engine, a tapered plenum design is used.

The manifold is compatible with all VW/Audi 1.8T applications, and its shallow profile means it can be used in many swap applications as well. It fits the stock throttle body, however, those looking for more power can order the 80mm option. SEM also offers longitudinal intake manifolds for VW Passat/Audi A4 1.8T, which are different in design but will have similar gains.

SEM motorsports intake manifold upgrade installation Photo 4/7   |   Thanks to the up-front intake manifold placement, installing the SEM piece is a quick and straightforward affair.

Results

Using Magnus Motorsports’ in-ground Dynojet, the stock manifold–equipped GTI spun the rollers to a peak whp number of 188, and torque crested at 208 ft-lb. We let the engine cool off for about 25 minutes, and then we attacked the stock intake manifold. It was off in another 25 minutes, and the new SEM intake manifold was bolted and buttoned up in no time. Having the manifold at the front of the engine makes this swap an easy one, which any novice mechanic can attempt.

The black finish of the SEM intake manifold adds a lot of style points to the engine bay, but performance is where it really shines. Power figures instantly jumped to 208 whp and an even more impressive 243 wtq. That extra volume really does pay off, and it’s not just in the high-rpm range. As the dyno plot shows, significant gains are made in the midrange and continue on to redline. Remember that this is a stock turbo, so it falls flat up top. With a better performing snail upper rpm, power production should increase significantly.

Often when air-altering modifications are made, boost pressure can increase—and that’s where the gains come from. We were careful to note max boost before and after the SEM intake manifold (23 psi), and it was within a half psi, so it’s safe to say that the design of the manifold can be credited for the extra power, not an increase in psi. It’s rare to see an intake manifold deliver more power without altering or shifting the powerband, but the SEM unit does just that. It delivers gains where they count, on both torque and horsepower fronts, therefore getting a big thumbs-up from us.

SEM motorsports intake manifold upgrade SEM manifold Photo 5/7   |   SEM Motorsports Intake Manifold - Upping The Velocity
SEM motorsports intake manifold upgrade stock manifold Photo 6/7   |   Not only does it look a hundred times better than stock, but it adds a stout 21 whp and 35 wtq to the powerband.

Gains Made

+ 20.64 whp
+ 35.19 wtq
Before 187.73 whp and 208.23 wtq
After 208.37 whp and 243.42 wtq

SEM motorsports intake manifold upgrade horsepower gains Photo 7/7   |   SEM Motorsports Intake Manifold Upgrade Horsepower Gains

BROWSE CARS BY MARKET

MORE HOW TO

What begins as an itch to lower your car's ride height, turns into a full-blown coilover installation. We should all be familiar with the thought process—because let's face it, wheel gap is just unattractive.
Ceso BagayFeb 21, 2019
WillyWerx, aka William Galan, figures heavily in this last entry of Ryan Hoegner's 911SC, giving a master class in proper vintage Porsche restoration
Bob HernandezFeb 14, 2019
Outfitting a GR WRX with fresh pads and rotors
Bob HernandezFeb 5, 2019
AC Schnitzer used data from 2 record-setting successes to dial in parts developments for the BMW F90 M5
Bob HernandezJan 31, 2019
Shifting our focus to the chassis, in particular revamping this Porsche's suspension as well as its brakes and topping it all off with a one-off roll bar
Bob HernandezJan 29, 2019
Sponsored Links

SEARCH ARTICLES BY MAKE/MODEL

Search
CLOSE X
BUYER'S GUIDE
SEE THE ALL NEW
NEWS, REVIEWS & SPECS
TO TOP