thats how they normally work, i rev mine up to 6000 and feather it off and it pops and flames about two feet long as well as little bursts, i had a few problems as i just fitted it and was not aware what was needed, so it diddnt work, went for a full decat, cold air kit, vta dump valve, and got small flames, messed around using different octane fuels and bobs ya uncle,