TH-style downpipe vs. ported elbow and 3" ??
- Thread starter Mark
- Start date
turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
The exhaust flowing in stock elbow ported or not hits a wall and has to make a direct 90 degree turn.
The Houston or same style allows the exh to flow right out w/out the abrubt turn.
The stock elbow is restrictive in several ways:
1. The hard turn(Wall).
2. Turbulence entailed with the hard turn the gases must make.
3. Outlet to small
I don't have numbers but when the downpipe makes a noticeable change on the vac/na side of the engine along with boost side then you tell me.
Freer flowing exhaust equals less exh reversion equals cleaner combustion equals more power(HP/TQ). The turbo is restrictive enough anything past you want as freeflowing as possible.
I held off for a while due to expense but finally purchased the 3"THDP and all I can say is the car is completely different. They are some great deals right now on them.
The Houston or same style allows the exh to flow right out w/out the abrubt turn.
The stock elbow is restrictive in several ways:
1. The hard turn(Wall).
2. Turbulence entailed with the hard turn the gases must make.
3. Outlet to small
I don't have numbers but when the downpipe makes a noticeable change on the vac/na side of the engine along with boost side then you tell me.
Freer flowing exhaust equals less exh reversion equals cleaner combustion equals more power(HP/TQ). The turbo is restrictive enough anything past you want as freeflowing as possible.
I held off for a while due to expense but finally purchased the 3"THDP and all I can say is the car is completely different. They are some great deals right now on them.
I tested a THDP vs. a ported elbow at Bristol in 2001 with a mid-high 11 car. 6 runs each with everything else pretty much identical.
Averaging the top 3 of each and comparing netted a .05 and 1.5 mph improvement with the THDP. The THDP seems to really help above 5K RPM and the car will make more HP with it. If you stay below 5K (and my car does except going through the traps) I didn't notice much of a difference (hence the .05 ET difference).
Spoolup is probably better with the THDP, but my car spools fine without one.
Mid 11s and faster, Turbos larger than a TA49, motors that rev more than 5K RPM, the difference will be larger than I saw.
Averaging the top 3 of each and comparing netted a .05 and 1.5 mph improvement with the THDP. The THDP seems to really help above 5K RPM and the car will make more HP with it. If you stay below 5K (and my car does except going through the traps) I didn't notice much of a difference (hence the .05 ET difference).
Spoolup is probably better with the THDP, but my car spools fine without one.
Mid 11s and faster, Turbos larger than a TA49, motors that rev more than 5K RPM, the difference will be larger than I saw.
