XRAY - Model racing cars

Hi,

I am considering changing to a .28 engine, but I would like to hear your guys advice.

The car is a XT8 2009, RB .21 WS7 III w/ RB EFRA 3001 pipe, the engine is rather new, properly tuned, and I cannot lean it more on either the bottom or high. Stock diff setup (7, 10, 7), stock gearing except I am using a 14T clutchbell. New Xray 1.71 alu shoes and extra hard springs.

The track (HRCR north of Copenhagen) is fast and in general I am happy with the way the car is handling using this setup. I need to use 14T gearing to have enough speed for clearing a fast, low double jump.

The only problem is, that the car does not accelerate fast enough from very low speed before two succesive, large double jumps. The buggies all do it easy, and I didn't have any problems when I was using a .28 Sirio engine.

I prefer the characteristics of the .21 engine so I'd rather stay with that. But I am considering switching to an .28 engine (e.g. RB RT28 or RT9) to solve the problem.

What are you guys thinking?

Thanks, Torben

Stick with the .21 and run a 13t clutchbell.

3 things. I have a couple friends that use your engine & have no problems on any of the jump infested short runup tracks we use here in southern califoria & their top speed is the same as everybody else & better on than most on long straight tracks & I almost never see loose a drag race coming on to the straight,meaning low rpm to high the motor builds power as quickly as most other motors.

Next is what I hear not experience because I dont have to use those new efra 3xxx series pipes but,I have head nothing but they kill power across the board & most people hate them.

Lastly,& I dont remember wher I read this(maybe Neo Buggy)but I think that many of the older 2xxx series pipes that make power are legal again for some reason.I would check into that as I do have experince with your motor making many buggy & truggys fly,unless there is something wrong with your particular motor.

Good luck.