What class of fuel scoop are you using? I am only using class 4, so maximum scoop rate is under 170 units per second.
4A... 343units/s is maximum and I'm fairly close to the star at that moment, but DBX is still doing OK and there is still some wiggle rom before hitting the exclusion zone... The temperature goes to roughly 64 or so... But I can park there at this scooping rate and stay there indefinitely, no harm to the ship... When I'm done FSSing the system, I hit accelerate (at that point I'm usually also refuelled) and when the star turns yellow on my radar, I hit Jump button while still being in the scooping zone, the temperature goes to roughly 70-80 before I leave the scooping zone, but then it drops back and I jump...
In boring systems with only a star or two and no planets, I usually traverse the star full throttle at distance that allows for around 300 units/s scooping, which nearly refuels the tank, but since there is no reason to hit FSS, I usually hit Jump button while still scooping at a rate of roughly 230units/s and jump shortly after I leave the scooping zone... Temp reaches roughly 87 or so but drops to 70ish when jumping... This way, I can do around 60 jumps per hour...
The outfit below is not perfect, I know, I was outfitting my DBX after playing for roughly a week or two, so I did not really know how to do it properly... But 27ly jump range suits my needs just fine... The 4A shield saved my butt plenty of time... I'm hitting planet surface fairly often (mostly because I know I'm invincible)...
I'm now heading to Colonia to fix my outfit for a longer jump range and also to fit an SRV...
4A SHIELD GENERATOR
4A FUEL SCOOP
3C AUTO FIELD-MAINTENANCE UNIT
3E CARGO RACK
2E CARGO RACK
2E CARGO RACK
DETAILED SURFACE SCANNER
1E ADVANCED DOCKING COMPUTER
4A POWER PLANT
4A THRUSTERS
5B FRAME SHIFT DRIVE
3D LIFE SUPPORT
4A POWER DISTRIBUTOR
3A SENSORS
5C FUEL TANK
1I LIGHTWEIGHT ALLOY
2F MULTI-CANNON [GIMBALLED]
2D BEAM LASER [GIMBALLED]
HEAT SINK LAUNCHER
POINT DEFENCE