This section of the TTP X-Files is about tuning the Bonneville/T100 and Thruxton Triumph twins with bolt-on modifications. The Bonneville, T100 and Thruxton use the excellent 360° engine which is of course the traditional Triumph twin engine configuration. It outlines our experiences using different induction and exhaust configurations which are outlined below.
The initial dyno run was carried out on a factory standard 2010 EFI Bonneville with around 4200 miles on the clock and the SAI system was removed. The induction modifications used were the TTP
Stage 1 Torque Induction Kit with and without the internal airbox baffle (stage 1.5) and the TTP
Stage 2 Power Induction Kit. The exhaust silencers/system used were the Triumph Off Road Silencers (TORS), short free flowing silencers of less than 20"/50cm (not including link pipe), long free flowing silencers of more than 20"/50cm (not including link pipe) and a complete 2-1 system. All of the dyno graphs shown have the 'Factory OEM' run as a comparison.
Induction Modifications
There are three common variations of airbox modification for the Bonneville/T100 and Thruxton. Deciding on which airbox mods are right for you is very much dependant on how much power you want, where you want the power to be produced and how much time and money you're willing to invest in your bike.
- Stage 1 Torque Induction Kit - Basic Airbox Mods.
- Stage 1.5 - (Stage 1 Torque Induction Kit plus internal airbox baffle removal, click here for guide).
- Stage 2 Power Induction Kit - Airbox Replacement & Pod Filters.
Induction Comparison Dyno Graphs
The dyno's below compare each of the three induction systems with a specific exhaust system. This enables you to see what effect changing the induction has on your chosen exhaust.
Exhaust: TORSTORS with Stage 1 - Best torque up to 3,900rpm, but then Stage 1.5 gives better torque up to 7,400rpm.
TORS with Stage 1.5 - Slightly less torque up to 3,900rpm than Stage 1, but then pulls away giving better torque through to 7,400rpm where the curves are very similar to the rev limit. Best mods for general riding.
TORS with Stage 2 - Best overall top end power, but a significant loss of torque below 4,900rpm compared to Stage 1/1.5. Only worth running Stage 2 if you ride above 6,000rpm on a regular basis and don't mind giving up some of your mid range.
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Exhaust: Long free
flowing silencers
Long free flowing silencers with Stage 1 - Slightly more torque up to 3,800rpm than Stage 1.5, but then Stage 1.5 pulls away giving better torque to the rev limit.
Long free flowing silencers with Stage 1.5 - Loses out slightly to stage 1 up to 3,600rpm, but with better torque from there to the rev limit. Best mods for general riding.
Long free flowing silencers with Stage 2 - Best for top end power, but no benefits below 5,800rpm compared to Stage 1/1.5. Best mods for top end power. As with TORS, only worth running Stage 2 if you ride above 6,000rpm on a regular basis and don't mind giving up some of your mid range torque.
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Exhaust: Short free
flowing silencers
Short free flowing silencers with Stage 1 - Best torque up to 4,000rpm than Stage 1.5 and 2, but then loses out to both up to the rev limit.
Short free flowing silencers with Stage 1.5 - Loses out to stage 1 up to 4,000rpm, but with better torque from those revs to the rev limit.
Short free flowing silencers with Stage 2 - Best overall top end power, but no benefits below 4,800rpm compared to Stage 1/1.5.
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Exhaust: 2-1 System
2-1 system with Stage 1 - Better torque compared to a standard bike, but the benefits from pulling the internal airbox baffle and going to Stage 1.5 are massive and well worth the effort involved.
2-1 system with Stage 1.5 - Best torque up to 6,300rpm and then Stage 2 does slightly better to the rev limiter. Best mods for general riding
2-1 system with Stage 2 - Massive loss of torque up to 6,300rpm compared to Stage 1.5 and then gains the upper hand to the rev limit.
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Exhaust Modifications
For our exhausts selection we chose TORS, long free flowing silencers, short free flowing silencers and a complete 2-1 system as these are representative of the most used exhausts by owners on the Bonneville/T100 and Thruxton. With silencers, if the exhaust note is louder, then generally they give better power at the top end and sometimes in the mid-range unless little thought has gone in to the silencer design.
Exhaust Comparison Dyno Graphs
The below dyno's compare each of the four exhaust systems with each of the three induction systems. This enables you to see what effect an exhaust has on a particular induction system.
Induction: Stage 1
Stage 1 with TORS - Better torque up to 5,700rpm than a 2-1 system.
Stage 1 with long free flowing silencers - Good torque up to 4,300rpm, but can be beaten throughout the rev range by the short free flowing silencers.
Stage 1 with short free flowing silencers - Generally the best torque throughout the rev range.
Stage 1 with a complete 2-1 system - The worst torque figures up to 5,700rpm and then starts to pull back eventually giving the best top end figures.
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Induction: Stage 1.5
Stage 1.5 with TORS - Much better torque than a standard bike, but gives the lowest torque figures compared to the rest, as expected.
Stage 1.5 with long free flowing silencers - Good torque up to 3,800rpm, but then the short free flowing silencers pull away.
Stage 1.5 with short free flowing silencers - Good torque up to 3,800rpm and then pulls away from the rest and only beaten by a 2-1 system.
Stage 1.5 with 2-1 exhaust system - Average torque up to 3,200rpm, but then gives the best torque up to the rev limit.
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Induction: Stage 2
Stage 2 with TORS - Lowest torque figures except up to 3,400rpm and between 4,600 - 6,000rpm where they beat the 2-1 system.
Stage 2 with long free flowing silencers - Very good torque up to 3,600rpm, but then the short free flowing silencers pull away in the mid range with similar figures from 5,400rpm to the rev limit.
Stage 2 with short free flowing silencers - Good torque up to 3,400rpm and then pulls away to give an excellent mid range and top end.
Stage 2 with 2-1 exhaust system - The torque curve for this system with the stage 2 is not that impresive until you reach the very top end.
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EFI Bonneville/T100 & Thruxton Power & Torque Quick Reference Guide
Please click the tune number to see the relevant dyno graph. |
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| Tune |
Induction |
Exhaust |
Peak Power (BHP) |
Peak Torque (ftlb) |
Max Torque Increase |
| |
| OEM |
OEM |
OEM |
+0.0% (60.64) |
+0.0% (46.84) |
+0.0% |
| 1 |
Stage 1 |
TORS |
+5.6% (64.06) |
+8.4% (50.78) |
+15.9% @ 4,200 rpm |
| 1 2-1 |
Stage 1 |
2-1 System |
+10.8% (67.19) |
+7.4% (50.30) |
+7.4% @ 4,200 rpm |
| 2 |
Stage 1.5 |
TORS |
+4.5% (63.40) |
+10.8% (51.91) |
+16.8% @ 4,200rpm |
| 2 2-1 |
Stage 1.5 |
2-1 System |
+13.8% (69.02) |
+16.0% (54.38) |
+26.6% @ 4,100 rpm |
| 3 |
Stage 1.5 |
Long Silencers |
+7.8% (65.36) |
+14.2% (53.48) |
+19.4% @ 4,200rpm |
| 4 |
Stage 1.5 |
Short Silencers |
+9.4% (66.34) |
+12.6% (52.76) |
+22.3% @ 4,200rpm |
| 11 |
Stage 2 |
Long Silencers |
+14.1% (69.23) |
+15.3% (54.02) |
+18.5% @ 6,300rpm |
| 11 2-1 |
Stage 2 |
2-1 System |
+17.0% (70.95) |
+11.4% (52.16) |
+16.9% @ 4,200rpm |
| 12 |
Stage 2 |
Short Silencers |
+14.3% (69.31) |
+15.6% (54.14) |
+21.0% @ 4,300rpm |
The Best Combinations
After studying the dyno graphs and riding with the various induction and exhaust configurations there is one setup that we consider the outright winner, but this is based on the riding experience and not looks or sound of the exhaust system.
There are usually three points that draws you to an exhaust system for your bike,
- How it looks.
- How it sounds.
- The power delivery/curve of the system.
Points 1 & 2 usually dominate because they are down to personal taste and what fits with your bike's style. Point 3 is usually mute because the information generally isn't available. Twin Power now gives you the missing information, so you can now consider point 3 for your style of silencer/exhaust system in your decision. The power delivery/curve of the exhaust system can now be used to balance the other two points.
So, we are going to give the top three configurations based on the best torque/power curves and riding experience.
- Stage 1.5 (airbox baffle removed) Torque Induction Kit with a 2-1 system. - This combo is easily the winner due to the excellent mid range torque and very good top end power. The maximum torque increase of 26.6% @4,100rpm is excellent and will give excellent tractability throughout the mid range which will increase acceleration times. The top end power isn't the best compared to other comfigurations, but 2 bhp at the top end is only noticable to the most experienced rider and for most owners the difference between 69bhp and 71 bhp peak power is negligable. The only downside that I see personally, is that the sound of a 2-1 system on a 360° twin can't touch a 2-2 system.
- Stage 2 Power Induction Kit with short free flowing silencers - Short free flowing silencers generally give a slightly better torque curve than long free flowing silencers. The top end power is usually pretty equal between the two types of silencers, but the way the short silencers deliver torque gives them the slight edge and of course they are usually louder than the longer silencers.
- Stage 2 Power Induction Kit with long free flowing silencers - This combination only just beats the Stage 1.5 with long silencers combo and this is due to the extra top end power that the Stage 2 gives. The mid range is better with stage 1.5, but with stage 2 you gain around 4bhp more power at the top end, which is noticable and fun to use.
We hope this article will help you to be informed about the bolt on power mods available and may help to make your Bonneville, T100 or Thruxton right for you.
Keep the rubber side down & ride safely,
Mike
We have a guide on how to remove the internal airbox baffle
HERE and our testing on air filters
HERE determined which filters to use.
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All text and dyno run graphics are copyright of Triumph Twin Power ©2008-
