Hellcat Spacer Plate Comparison

hellcat spacer plates before run comparison
hellcat spacer plates 6200rpm comparison
Results are very impressive to say the least, as I’m sure you guys know this car is at high altitude 6000ft + so gaining HP is a difficult task.

Boost pressure has 100% been leaking via the stock intake gaskets, I’ve broken down 5000rpm and 4000rpm but haven’t bothered with screen shots as I don’t have the time, results are very similar to 6000rpm they are:

No spacer / Spacer fitted
5003rpm / 5004rpm

44% IDC / 45% IDC
11.92 AFR / 11.87 AFR
194.1KPA / 199 KPA
16.5 Deg timing / 15.5 Deg timing
109.4f (43c) IAT / 98.6f (37c) IAT

No spacer / Spacer fitted
4000rpm / 4002rpm
34% IDC / 36% IDC
11.92 AFR / 11.87 AFR
198 KPA / 201 KPA
11.3 Deg timing / 10.1 Deg timing
105.8f (41c) IAT / 96.8f (36c) IAT

Since this car is at altitude and making less boost pressure to sea level the breach of boost pressure at sea level might be higher with the higher level of boost being created.

Currently it is losing 2.72% of the boost 0.75psi (without the plates).
In effect the spacer plates are gaining back and increasing boost pressure by 0.75psi.
(0.75psi gain in boost pressure might be higher at sea level)

It’s also a very good result to see a 37rwhp gain with timing being 1 degree lower, you could imagine seeing another 10-20rwhp with 1-2 degree’s more timing being added in the tune.


AFR and IDC both show that it was also slightly richer on the spacer plate run.

Without the spacer plates fitted you can imagine the pressure in the crankcase is much higher, the pistons are going to struggle pushing down into that pressurized crankcase.

Now that the boost isn’t leaking into the crankcase the pistons will travel down with more ease and the engine will be able to accelerate faster as well as the gain in HP acquired from the colder intake temps/increase in boost pressure.

Install video, before/after dyno results

In summary:
You’d rather your boosted air pressure enter combustion vs the crankcase
The colder IAT is because the entire blower is now running colder being isolated from the engine
As well as the IAT sensor being more isolated from the heat source of the engine
Less pressure in the crankcase, engine will accelerate faster
hellcat spacers before and after