WC Engineering : Comparing Turbo Specs

WC Engineering > Technical Articles > Comparing Turbo Specs

Comparing Turbo Specs

1990-1994 Lotus Esprit SE: T3-50
1994-1995 Lotus Esprit S4s: T3-60
WC Engineering Stage I: T3/T4 Hybrid Ceramic BB
WC Engineering Stage II: T3/T4 Hybrid Ceramic BB

Turbo Vocabulary
CFM:	Air flow in cubic feet per minute at 15°C. 1.5 CFM is required for 1 HP. 13.07 CFM is 1 pound of air at 15°C.
PR:	Pressure ratio. Output pressure of turbo referenced to absolute zero pressure. NOTE: figures here are described as pressure above atmospheric.
PPM:	Pounds per minute of air flow.
RPM:	Shaft speed in RPM. Higher RPM causes more heating of the charge air.
Eff:	Efficiency. The higher the efficiency, the less heating of the charge air.

T3-50

Trim Size
50

Maximum Flow
30 lbs/min at 2.20 PR with 58% Eff and 157,000 RPM

Optimum Flow
From 11 lbs/min at 1.5 PR through 21.4 lbs/min at 2.3 PR

With the given information, the T3-50 turbo used on the Lotus Esprit can provide a maximum 30 lbs of air or 392 CFM or 261 HP sustained.

T3-60

Trim Size
60

Maximum Flow
34 lbs/min at 2.3 PR with 64% Eff and 143,000 RPM

Optimum Flow
From 11 lbs/min at 1.4 PR through 23.1 lbs/min at 2.3 PR

Power output at maximum flow is 296 HP sustained.

WC Engineering Stage I Ceramic Ball Bearing Turbo

Maximum Flow
41 lbs/min at 2.4 PR with 65% Eff and 115,000 RPM.

Optimum Flow
From 15 lbs/min at 1.6 PR through 30 lbs/min at 2.6 PR

Power output at maximum flow is 357 HP sustained.

When operated in the normal Esprit parameters of the 2.0 PR (14.7 psi of boost), this unit provides 25 lbs/min of air while still inside the 76% efficency window. The SE turbo only provides 15 lbs/min at this level and the S4s turbo only provides 17.5 lbs/min.

WC Engineering Stage II Ceramic Ball Bearing Turbo

Maximum Flow
47 lbs/min at 3.0 PR with 72% Eff and 126,000 RPM.

Optimum Flow
From 17 lbs/min @ 1.6 PR through 37 lbs/min at 2.5 PR

Power output at maximum flow is 409 HP sustained.

When operated in the normal Esprit parameters of the 2.0 PR (14.7 psi of boost) this unit provides 34 lbs/min of air while still inside the 76% efficency window. The SE turbo only provides 15 lbs/min at this level, and the S4s turbo only provides 17.5 lbs/min.