Sorry I didn't respond earlier , I have been busy with a furniture project. To answer the question at hand, the turbo adds power and in some cases speed but never top end speed. Let me explain: assume stock worksite tires. On flat ground w/o turbo the rtv would go 30 mph, with turbo it will still only go 30 mph but get there quicker. The speed of the rtv is limited by the engine revs and gearing. When I initially turned up the pump I also adjusted the throttle cable so the engine revs a bit higher giving me a little more speed. The turbo does absolutely nothing to increase the max rpm, so w/o changing the gearing or trans will not increase the top speed.
The turbo does increase speed going up a hill over stock because the machine has more power to maintain a higher speed. Again the top speed will not change. In other words, say I could go up a hill at 15 mph w/o turbo with my foot to the floor, with turbo I might go up the hill at 20mph because of the extra power, but in no event would I go over 30mph.
The deal with the surefoot tires is that in stock form the rtv would only go 17 mph because of the drag of the bigger tires; the extra size and weight of the tires, the drag from the aggressive tread and the extra width. With the turbo it will go 27mph because the the machine now has the power to reach max speed. I believe the reason the speedo only registers 27 mph is because the bigger tires throw off the reading.
