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Don't let the Harley heat monster ruin your riding.
Reduce  Engine Surging
Improve Throttle Response
Reduce Engine Ping


HD 2007/2008 Engines

High Heat on 2007/08 HD engines

HD 2007/08 Performance Recommendations

Cool your exhaust temperature with the Wide Band O2 upgrade for 2007/08 HD

Harley Camshaft Specification Tables

HD Twin Cam Engine Builds
TC 128 HP 95 CID
TC 100HP Street Engine

The basics of Fuel Injection explained

Rammer Performance Air Cleaners
TC Performance Heads 100+HP

Pro Tuning on a Shade Tree Budget


2007/2008 Harley-Davidson Engine Performance

Harley-Davidson's new line of 2007/2008 engines is a major shift from previous years. The Twin Cam engine size has grown from 88CID to 96CID with a longer stroke. The HD CVO engines are now 110 CID. There are upgrades to the standard 96CID engine to 103CID by installing a "big bore kit" and to 110CID by installing a stroker crankshaft with the big bore upgrade. All Twin Cam bikes now have 6 speed transmissions. The very problematic cam area has also been re-engineered, requiring different cams from previous years (with the exception of 2006 Dyna models).

The 2006 Dyna's and all HD 2007 engines have a reputation for very hot exhaust systems. This problem is well documented for the 2007 FLH's, but does exist on all the bikes. This issue is directly related to the EFI closed loop operation mode at idle and cruising speeds. In closed loop mode, the narrow band O2 sensors used by the Delphi ECU hold the air fuel ratio at 14.7:1 which is good for EPA compliant emissions but creates a very hot exhaust pipe. Nightrider has a fix for this issue that will reduce the exhaust temperature, lower the operating temperature and improve throttle response.
Nightrider has come up with a fix for this problem. Read about our fix  here.

An even bigger change is the fact that all HD's including Sportster, now have fuel injection with dual O2 sensors. This allows the engine to run in a closed loop mode of operation where the fuel mixture is controlled by the 02 sensor.

While HD does not publish horsepower numbers in its sales literature for the 96CID (1584cc) or 110CID engines, Nightrider was able to find horsepower numbers from Harley. As you can see below on the dyno sheet listed below (Figure 1), the TC96CID engine for Dyna's and Softail'sproduces around 68 horsepower and 83 torque in stock trim. The same bikes with an HD/SE Stage 1 engine makes around 81 horsepower and 96 torque. We have additional HD/SE engine configuration HP/Torque numbers in our Twin Cam HP Gallery.

2007 HD Twin Cam 96CID Dyno Chart
Figure 1

Additional Dyno charts located on FLH based bikes (Figure 5) show the large difference in power. Stock FLH's produce 71 horsepower and 90 of torque. This same engine in HD/SE Stage 1 trim makes 79 horsepower and 96 of torque.

The difference in power between Dressers and Dyna/Softails is due to the exhaust system. FLH's have a very large volume in the exhaust system which allows the exhaust to fill this space while the noise is being dampened prior to exiting the mufflers. This shows the benefits of a crossover in the exhaust and having larger mufflers. While few riders are willing to put FLH sized mufflers on their Dyna or Softail, it does show the effectiveness of the FLH exhaust in streetable engine combinations.

Harley-Davidson did publish some interesting power improvement percentages in the Fall 2006 issue of its Enthusiast newsletter.  From the information listed below it must be assumed that you can upgrade the exhaust system and intake system on your 96CID engine without any changes to the ECU. Nightrider has historically been a proponent of exhaust system only upgrades with no EFI remap, but now HD has published that HD/SE exhaust upgrades and no EFI upgrades can be added to your bike without warranty implications. The table below summarizes power improvements as published by Harley-Davidson.

  Maximum % Power Improvement
No Remap
Maximum % Power Improvement
HD Stage 1 Remap
HD SE SE Street Power Mufflers
SE Air Cleaner Kit
SE Street Power Mufflers
SE Air Cleaner Kit
SE ECM recalibration
Twin Cam 96CID 3% torque
7% horsepower
7% torque
12% horsepower
Sportster 17% torque
8% horsepower
22% torque
15% horsepower

Recommended Upgrades for 2007 HD Twin Cam engine

More Dyno Charts
Figure 2
2007 HD Sportster Dyno Sheet
Figure 3
2007 HD Dyna Dyno Sheet
Figure 4
2007 HD Softail Dyno Sheet
Figure 5
2007 HD FLH Dyno Sheet

Recommended Upgrades for 2007 HD Twin Cam engine


Table of Contents
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Nightrider COPYRIGHT

Ask us a Question

Modification, Installation, Maintenance and Tuning Index  will help you find most of the information you want on one page.

How to get Professional Tuning Results at home
Testing the Innovate Motorsport LM-1 portable air fuel meter

Profession Tuning on a Shade Tree Budget

Veypor VR2 Data Logger and Instrument Panel
Video Installation and Demo
Purchase VR2

Engine Performance
How to Build a
TC96 2007 Engines
TC88 70HP Stage1  
TC95 128HP Stage 3
TC95 100HP Street
TC96 2007 Stage 1/2
EVO 64 HP Stage 1
EVO 74 HP Stage 2
EVO 82 HP Stage 3
EVO 95 HP Stage 3
883 to 1200 Upgrade
Shovelhead Modifications

New EFI for EVO and TC

Performance Gallery
Horsepower Gallery
Evolution 80
Twin Cam 88/95
Evolution Unlimited
Sportster Unlimited
Drag Strip Gallery
Land Speed Racing Gallery
CV Carburetor
Modifying the CV carb
Tuning a CV carb
Selecting a cam
Install a TC 88/95 cam
Install a Big Twin cam
Install Sportster cams

Camshaft Specifications
Twin Cam

Exhaust Systems
EVO Exhaust Testing
TC Exhaust Testing
Khrome Werks AR100 test
Making Drag Pipes Work

Shop Manual
Carburetor Troubleshooting
Finding Manifold Leaks
Cylinder Heads
Pistons and Cylinders
Belt Drive
Shop Manual Appendix
$20 Bike Lift
Plug Wires
Spark Plugs
Engine Tuning
Nitrous Oxide
Motor Oil
Stutter Box
General Information
WEB Links
Buy Books and Manuals
Performance Calculations
Estimate Horsepower
Estimate 1/4 Mile Time
Estimate Top Speed

Engine Displacement
Exhaust Length
Gear Ratios
Air Density

The Nightrider Diaries
The ramblings of a genius a, a madman and something in between.

Where is Sifton Cams?

Autocom Active-7 tested

Harley-Davidson EFI
-EFI basics explained
-EFI modifications explained

183 HP, 2 carbs, 2680cc

Copyright 1997-2006  Stephen Mullen, Oldsmar, FL -+-