V-Twin Boost Plug-In Fuelling Fixer

Has anybody fitted the v twin boost supplied bt Gussibits? States it smooths out lower speed and increases inital acceleration? Be interested ti hear from anyone that hasd fitted it?

yes I have it, and the velocity stack and big bore header pipes and crossover.

VTB was fitted first, and used for a few weeks with no other upgrades.

The v twin boost on its own does make a difference but it’s subtle, slightly better pick up at low speeds.
Velocity stack then added makes another small improvement, so fitting both together at the same time you will notice more of a change.

Removing the catalytic converter made a much bigger difference, with all three of these modifications the bike is so much improved I wish I had done it when I bought the bike.

Much more fun to ride, great improvement to throttle response. Riding modes make a much more noticeable change now with sport mode feeling a bit too twitchy in town but great on fast rodes. Engine braking is reduced but I felt it was too much before and needed constant throttle input or the bike would slow down quickly.

Top speed doesn’t seem higher but I’ve not been able to fully test that yet, however it goes up through the gears way quicker. Pulls from lower in rev range, 2500rpm and up feels good but even down to 2000rpm there is still better response. It will redline easily now if I’m not gradual with throttle, it picks up so fast.

At 5k rpm set on cruise control it used to sit at indicated speed of 80mph, now it’s 83mph.

Oh and the sound, even through the standard silencer, is now a proper rumble with a nice pop now and then on deceleration. I have the mistral conical silencer on order too, according to Mistral this won’t change HP just sound and small torque increase.

For insurance purposes I emailed Mistral who were very helpful and gave me the estimated total increase in HP for all parts fitted as 5.5. Dyno charts available on website as well for most parts.

I definitely notice the increase when overtaking now, I can stay in one gear higher than before in many situations and am having to relearn my gear changes a bit. It is less snatchy at low speeds (except sport mode, because it picks up faster), greatly improved on open roads, sounds better… The only downside apart from cost is if you have neighbours and are in/out at night it’s a bit louder, but it’s not massively louder, just the exhaust was so quiet before it will be more noticable.

Very happy with the total package, expensive but worth it. VTB on its own not a dramatic improvment. I think its designed to work best in conjunction with the bigger headers and crossover pipes.

Thanks for the heads up and comprehensive explaination. Did the insurance accept the figures and did it make mach difference to annual premium? Cheers Tonybrode

no change to premium at all and they accepted the figures as I forwarded the email from mistral to the broker.

you can see the VTB sensor wire in the photo I uploaded to the foglight connector/USB plug thread, the black wire in the left lying across the frame.

usually it rests in the glove tray

Hi, I’d love to know how the “upgrades” you made changed the gearing such that the bike went went faster for the same rpm. Is some sort of magic involved?


I don’t think you’re actually interested and just want to point out it’s mechanically not possible, so you work away and explain that to me and I’ll carry on enjoying my bike.

the speedo isnt accurate anyway so I’m not bothered about a 3mph difference, it rides better and yes they are upgrades, no magic involved.


I’m not going to get involved in the booster plug debate one way ot the other, but I think thishttps://www.grisoghetto.com/t1426-booster-plug?highlight=booster+plug is worth a look:

Griso Ghetto is generally a reliable source of information and I’d be inclined to take on board what is offered.

lol, pretty unanimous opinions there.

on the plus side it’s easy to remove, I’ve seen reviews saying it improved the running after fitting the crossover pipes rather than being fitted first as I did, I’ll take it off and see what difference there is.

i looked at beetlemaps but afaik he doesnt do V85tt maps yet?

I had found this too:

That looks interesting. As with any map change, always good to be able to revert to the standard map, should the need arise…

A question - has anyone got a computer hookup with their V85TT yet and if so can you do the normal servicing and diagnostics with it?

Alternative - you can get your bike mapped and dyno at somewhere like BSD nr Peterborough, there are other around such as Hilltop. I had used a few of the beetle maps, but had an area in the map that needed sorting so I went to BSD.

is there a beetlemap now for V85TT? the last I had read was he wasn’t able to get into the ECU so hadn’t made one for it yet.

It must be doable since the company I posted above seem to offer it.

I found this link about fuel injection systems that mentions marelli specifically which may be of interest:


Booster plugs will not have an effect during closed loop operation but still affect open loop, how much it gets adjusted during learning mode to even out the differences between the two modes seems to be the question.

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That’s what i enjoyed about this club/forum. There is always a wealth of information and advice about most subjects; with generally respectful debate and opinions.
Cheers Tonybrode

I suppose I should mention I have a 1200 sport…

Wow what an informative read. Thanks Sid :+1:

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