Discussion
A few of the guys I race with have been trying different things over the years to try and get that extra bit of performance without either pushing them over the class horsepower limit or jeopardising reliability. The latest thing they have been playing with is Ram Air. Not wanting to miss the boat or rely on others efforts (too much anyway) I want to have a bash at doing some close season ‘development’ work. The bike is a ’89 TZR 250 1KT, currently pushing out 53bhp on a dynojet, which is about 50/51 on the dynopro. Class limit is 53 on the dynapro.
So far the results have been negligible, with the only positive report coming from Snetterton where the rider felt a sudden increase in power down the back straight. Unfortunately this was happening too far down the straight for it to have any real benefit as it kicked in just as they were approaching the 150 marker. This was using nothing more than a hoover tube cable tied under the nose of the fairing and being fed in to the back of the air box. No mechanical force whatsoever, relying on momentum only to force the air.
So …ideas wise…I would like to run something small either side of the bike, say 38mm, as space is tight. Anything bigger could be squeezed in, but could suffer from being kinked which could hinder its operation. Termination would be a heath robinson affair into the back of the box, with the ‘funnel’ being in the same place as other bikes would have.
Fairings come off very regularly, so the ‘funnel’ needs to be easily detachable.
Does anybody have any ideas where (a) I can get bits from, like a funnel or bellow, whatever you would call it, and (b) and how can you get it to kick in earlier using the results from Snett as the model?
So far the results have been negligible, with the only positive report coming from Snetterton where the rider felt a sudden increase in power down the back straight. Unfortunately this was happening too far down the straight for it to have any real benefit as it kicked in just as they were approaching the 150 marker. This was using nothing more than a hoover tube cable tied under the nose of the fairing and being fed in to the back of the air box. No mechanical force whatsoever, relying on momentum only to force the air.
So …ideas wise…I would like to run something small either side of the bike, say 38mm, as space is tight. Anything bigger could be squeezed in, but could suffer from being kinked which could hinder its operation. Termination would be a heath robinson affair into the back of the box, with the ‘funnel’ being in the same place as other bikes would have.
Fairings come off very regularly, so the ‘funnel’ needs to be easily detachable.
Does anybody have any ideas where (a) I can get bits from, like a funnel or bellow, whatever you would call it, and (b) and how can you get it to kick in earlier using the results from Snett as the model?
Airbox has to remain the same.
I had always expected it to be in the nose rather than the sides.
Mixture - hadn't considered this. Currently there is only one circuit this would concern me, Snett
Steve...why does it only come in at 100mph? Is there any way of forcing it below that speed?
I had always expected it to be in the nose rather than the sides.
Mixture - hadn't considered this. Currently there is only one circuit this would concern me, Snett
Steve...why does it only come in at 100mph? Is there any way of forcing it below that speed?
The airbox draws air from a opening approx. 70mm x 40mm that on the standard bike would have a trumpet on it. We run without these. It faces towards the rear, close to the battery but it is not ‘fed’ air it is just freeflow. It has a decent amount of free area around this.
The filter is your normal road affair, fitting flat, suspended in the airbox. The carbs are connected to the airbus via the rubber inlets which are in good condition and make a good seal
The filter is your normal road affair, fitting flat, suspended in the airbox. The carbs are connected to the airbus via the rubber inlets which are in good condition and make a good seal
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