Updated: 14/03/04

My Serpent Impulse Pro

This is my Serpent Impulse, the car started life as the 2 speed Streetspec version. As you can see from the pictures by clicking the thumbnail images in the left hand table, the car has been upgraded with the addition of various Carbon Fibre and Aluminium option parts to improve the car beyond the spec of the Pro version.

When I was looking to buy the Carbon Fibre Top Deck, Serpent had announced the release of the new 705 so I had a real dilemma whether to wait for the conversion kit for the Impulse to 705, or proceed with the upgrade to Pro spec, by December 2002 Serpent still hadn't released the 705 and there was no word when the conversion set or any of the other upgrades would be available. At this stage I decided that the capabilities of the Impulse Pro, were far greater than mine as a driver, so I elected to carry on with the upgrade to Pro spec.

Ultimately the car will end up as a hybrid of Impulse Pro and 705 parts, my next additions when they are released will be the new Centax II clutch and LC Gearbox. I'm still running the standard rear Diff but really like the idea of the adjustability of the FPS Differential, however having seen various posts on the Serpent Forums indicating that the FPS Diff is too heavy for use on the Impulse I have had second thoughts. I recently spotted a post by Ronald Baar that suggested that Serpent are developing an addition for the standard Ball Diff to enable more adjustability, and that this may be available by February 2003 (watch this space).

The car is awesome! I'm running a Novamega SX12-RE, i've recently installed the Novarossi 5264 In-Line exhaust instead of the original .12/C1, this has really lifted the performance of the car, both in terms of acceleration and top speed. The installation of the Carbon Fibre top deck has lowered the centre of gravity significantly, the receiver, servos, fuel tank and battery pack now sit about 3mm lower than they did on the old composite top deck. With the aluminium braces installed in combination with the new top deck the car is now a lot stiffer. One of the problems that I have discovered with the car is finding wheels that fit, and don't rub on the rear uprights underneath the ball adjusters and the top and bottom of the front steering blocks. The Serpant wheels clear in these areas but because there isn't a lot of meat on the rims they flex and break easily. Most other manufacturer's wheels rub which affects the handling and performance, then they overheat and break. I have recently discovered the Graphite wheels supplied by a company called Modeltech, these wheels clear the uprights and steering blocks, but are also very light and stiff, this should have two benefits. 1/. The unsprung weight is lower, this should allow the suspension to work more efficiently by reacting to bumps faster. 2/. The gyroscopic effect shouldn't be as pronounced allowing the car to change direction more easily. When the weather improves and I can get some serious track time in, I should be able to evaluate their performance and give some proper feed back. Another problem that I have experienced is with rear end grip, mainly when coming off the power for corners and again when re-applying to power out. However, since receiving my Hudy Set-Up System I have stopped setting the car up as per the Serpent manual. I no longer set elevated camber because I was having to apply to much spring preload on the shocks to achieve the correct driving camber, it also meant that the car wasn't settled on its suspension and the ride height was a touch high because of that. I now set the down stops first as per the manual, followed by the ride height, then I adjust driving camber using the pivot balls only.

This updated procedure is recommended by both Serpent and Hudy, check out Michael Salven's publication for further details. I haven't had chance to test the car yet, but it certainly seems more compliant on the bench, the suspension sags out a little more, this means when you lift the front or rear of the car the wheels stay in contact with the ground longer, before there was very little sag, this I believe would cause the wheel to leave the ground too soon when it is unloaded, possibly being the main reason for the car spinning out, but only track time will tell!