How Much Horsepower Loss....

[BB]

....from using lower grade of gas than premium???

Withgas prices as they are, I've been using the mid-grade gas lately to save some $. I can tell that there is some loss of HP with the lower grade of gas.

On the way home today, i got to wondering, does using the lower grade of gas result in an actual loss of HP or is the decrease in performance due to something else when the timing is adjusted to compensate for less octane.
Curious,
Bill

[Mean Green]

Originally Posted by BB

....from using lower grade of gas than premium???

Withgas prices as they are, I've been using the mid-grade gas lately to save some $. I can tell that there is some loss of HP with the lower grade of gas.

On the way home today, i got to wondering, does using the lower grade of gas result in an actual loss of HP or is the decrease in performance due to something else when the timing is adjusted to compensate for less octane.
Curious,
Bill

Timing is pulled and power is lost. All that to save a measly $1-$1.50 a tankful by using mid grade. IMHO it isn't worth it.

[BB]

Understood MG!

But.....how much HP loss is there? Anybody know?
Bill

[CREWZIN]

BB,

In order to measure HP loss you'd have to put you car on a dyno. Have you ever seen a dyno pull in person. The engine is taken to red line a few times to get accurate readings. Putting a lower grade gasoline in the tank and having the computer retard the timing would mean your redlining the engine in a non-optimal configuration.

First a couple of pulls with premium gas to get a base-line reading then again when you use up that gas and fill up with a lower octane gas to find out what you already know.

Will it damage anything? Let us know when you try it.

[Taggert_LOA]

Originally Posted by BB

Understood MG!

But.....how much HP loss is there? Anybody know?
Bill

I would say atleast 10-15 hp. but it's not the HP it's the fact the computer retards timing and dumps fuel to prevent detenation killing MPG. you will actually spend more money, buying a lesser grade fuel more often. it's kinda a dumb question to ask. you bought the car knowing what grade fuel was required. if 4.25 a gal is too much then trade it in and get a camry.

[Dream4]

Originally Posted by BB

Understood MG!

But.....how much HP loss is there? Anybody know?
Bill

As you may or may not know, the only difference between the GT HO 220-230hp and the 180hp "turbo lite' is the PCM, along with the use of the higher octane fuel, the increased hp is from more timing and boost, allowed by the higher octane fuel, along with more fuel by increased injector pulse time, so if you use regular gas as used in the 180hp turbo, the timing is pulled back due to spark knock, along with lower boost levels because of the timing cutback, you will be very close to the 180 "turbo lite" levels, but running rich due to injector programing at WOT, you will still use the same amount or more of gas, but with approx 40 less hp. So you will spend the same amount or more money for the same mpg because of the programming of the PCM. Now if you had the proper programmed PCM you might save a little at the pump depending on your type of driving.

If you had a boost gauge you could the tell approx. the difference, as the "lite" runs about 10 psi of boost stock and the GT HO approx. 14 psi, and it is about 8 to 10hp increase, or decrease for every pound of boost gained or lost.

[bados]

Also, I think another difference between the 180 light and HO is that the HO has larger injectors.

I use Costco gas here in So. Florida. It's 93 octane for the price of mid grade. The attendant there told me the gas is supplied by Amoco. Car runs great, performs grade without any problems.

[CREWZIN]

Originally Posted by bados

Also, I think another difference between the 180 light and HO is that the HO has larger injectors.

I could be wrong, but starting in 2004 all PT Turbo's had the same injectors (bigger) and there were still Turbo Lite's being sold so the main difference would be the computer programming.

Stage 1 only included a new computer from 2004 upwards to prove my point.

[Dream4]

Originally Posted by bados

Also, I think another difference between the 180 light and HO is that the HO has larger injectors.

All injectors in both the 180hp and the 220/230hp engines are the same after 2003, the '03 turbo engine was only 215hp and had 47.4 lb/hr = 524.7 cc/min, (There was no "lite" turbo in '03), The '03 Stage 1 kit, and all 2004 and up turbos have 52.2 lb/hr = 577.1 cc/min injectors, the only difference is PCM programming, all other parts in the 180 & 220/230hp engines are the same, other than the late '05 & up 230hp engines have the newer composite intake manifold.

[CREWZIN]

Originally Posted by Dream4

All injectors in both the 180hp and the 220/230hp engines are the same after 2003, ...... The '03 Stage 1 kit, and all 2004 and up turbos have 52.2 lb/hr = 577.1 cc/min injectors, the only difference is PCM programming

I think that's what I just said.