T7Design | Honda K20 K24 Electric Water Plate Kit - Black

Honda K20 K24 Electric Water Plate Kit - Black

T7Design | Honda K20/K24 Alternator Underdrive Pulley 20%

Honda K20 K24 Alternator Underdrive Pulley 20%

Honda K20 K24 Alternator Underdrive Pulley 10%

£66.00 £55.00
Availability: In stock

Honda K20/K24 Underdrive Alternator Pulley 10% - Black

The T7Design Alternator Underdrive Pulley increases performance by reducing the force needed to overcome the inertia of the alternator during acceleration and gear changes, this will result in a snappier throttle response and more horsepower reaching the wheels.

Alternators, in general, have a broad generating power band with the Honda K20 alternator producing a reasonable output from just 1,500 rpm, with max output being produced from 4,000 to 18,000 RPM, with this latter figure technically being the maximum warrantied rev limit. In some applications, where the engine is spending most of its time in the upper half of its rev range, you simply do not need to drive the alternator at such a high speed. However, the only issue you would potentially face is a lower output at idle, in which case you may need to increase the idle speed to ensure the alternator is producing more current than is being consumed by the vehicles electrical systems. An underdrive pulley should also be considered if you have raised your rev-limit of your engine, for example if it is now 10% higher we would recommend fitting a 10% underdrive alternator pulley and so on.


  • Underdrives the alternator pulley to free up additional Horsepower.
  • Hard anodised black for superior finish, corrosion resistance and wear resistance.
  • Precision machined to very tight tolerances.
  • Almost half the weight of the OEM steel pulley.

Specification Metric Imperial
Weight - 10% Underdrive 0.145 kg 0.319 lbs
Weight - 20% Underdrive 0.175 kg 0.385 lbs
Weight - 30% Underdrive 0.177 kg 0.390 lbs
Weight - 40% Underdrive 0.203 kg 0.477 lbs
Weight - Stock Steel Pulley 0.275 kg 0.605 lbs
Construction Billet 6061-T6 Aluminium
Finish Hard Anodised Black
Manufacturer T7Design
Part Number 73F-3C7-D49
  • It is recommended to use an impact gun to remove the original alternator pulley.
  • Fits both models of Honda K20/K24 alternator.
  • For road applications we would not recommend going less than the 10% underdrive pulley, any less and you may find the OEM alternator cannot provide enough charge at idle with all electrical accessories turned on.
More Information
Honda Engine Code K20, K24
Honda Vehicle Code DC5, EP3, FD2, FN2
Vehicle Model Accord, Civic, Integra
Manufacturer T7Design

Shipping Information & Charges

VAT is included on the UK prices below, no VAT is applicable on ROW prices.

European Customers: We offer a next working day delivery service to most European countries, please get in touch for pricing.

ROW Customers: If you would like a more accurate shipping quote or a faster service via DHL please get in touch with your requirements.

United Kingdom & Northern Ireland

Service GBP 0 - 50 (inc VAT) GBP 50+ (inc VAT)
RM Second Class 3.60 N/A
RM First Class 4.20 N/A
DPD Next Working Day 9.00 9.00
DHL UK Next Working Day 8.75 8.75
DPD Next Working Day by 12am 16.50 16.50
DPD Saturday All Day 15.00 15.00
DPD Saturday by 12am 39.50 39.50
DPD Sunday All Day 19.50 19.50

Scottish Highlands & Islands, Channel Isles, Scilly Isles, Isle Of Man, Isle of Wight
Service GBP 0 - 50 (inc VAT) GBP 50+ (inc VAT)
RM First Class 4.20 N/A
DPD / DHL Two Day 17.30 17.30


DHL Tracked Delivery. Approx 2 - 7 days depending on distance from the UK.

Country Cost in GBP
AUT - Austria 30.00
BEL - Belgium 25.00
BIH - Bosnia and Herzegovina 50.00
BGR - Bulgaria 45.00
HRV - Croatia 35.00
CZE - Czech Republic 35.00
CHE - Switzerland 42.00
CYP - Cyprus 75.00
DNK - Denmark 30.00
EST - Estonia 35.00
FIN - Finland 35.00
FRA - France 35.00
DEU - Germany 28.00
GIB - Gibraltar 46.00
GRC - Greece 40.00
HUN - Hungary 35.00
IRL - Ireland 25.00
ISL - Iceland 50.00
ITA - Italy 32.00
LVA - Latvia 46.00
LTU - Lithuania 45.00
LUX - Luxembourg 26.00
NLD - Netherlands 26.00
NOR - Norway 45.00
POL - Poland 35.00
PRT - Portugal 35.00
ROU - Romania 45.00
SRB - Serbia 45.00
SVN - Slovenia 35.00
SVK - Slovakia 35.00
ESP - Spain 30.00
SWE - Sweden 35.00

Rest Of World

Below are the most popular countries we ship to world-wide. If your country is not listed please get in touch for a quote.

DHL Express: We offer shipping via DHL, please get in touch for pricing and more information on their Worldwide 1-2 day services.

Country Cost in GBP
CAN - Canada 60.00
JAM - Jamaica 50.00
JPN - Japan 70.00
MLT - Malta 58.00
MYS - Malaysia 50.00
NZL - New Zealand 52.00
RUS - Russia 50.00
ZAF - South Africa 49.00
THA - Thailand 55.00
USA - United States of America 70.00
SGP - Singapore 90.00


By Order Value: GBP 0 - 50 GBP 50 - 120 GBP 120+
AUS - Australia 40.00 60.00 80.00