Old gas cause a major HP loss?

[eric1h]

So I am pretty sure i know the answer...

I have been going over the car and every possible scenario to address the low HP numbers on my LS1

One thing that turned on the light bulb... the last time my car ran on track was the first week of April... I don't think i put any new gas in the since then and not sure if I had any gas treatment in there.

Could the old gas cause the low #'s I know old gas can cause pinging and other issues, but would the octane rating be low enough to cause crappy numbers but still run ok?

Just a thought...

i did drain the tank today and will refill with some 93 + Stabil gas treatment, and car goes back to the dyno tomorrow for some further tuning...

[Gatorac]

369rwhp is 434hp figuring a 15% drivertrain loss. How much were you expecting from that LS1?

[Panoz26]

Originally Posted by Gatorac

369rwhp is 434hp figuring a 15% drivertrain loss. How much were you expecting from that LS1?

[Dawgfan]

Thought I might chim in. I run Shell 93 octane and I feel I get pretty good performance with my 4.6??????????

[PRO SYSTEMS]

It depends on the fuel. But storing most oxygenated fuels in plastic jugs these days is a no-no. VP Q16 fuel for example has to be stored in a steel container. If you store it in plastic jugs or leave it in your fuel cell, in about a week a 700 h.p. engine will lose about 20-25 h.p.


Patrick James
PRO SYSTEMS

[Jim woodruff]

Originally Posted by PRO SYSTEMS

It depends on the fuel. But storing most oxygenated fuels in plastic jugs these days is a no-no. VP Q16 fuel for example has to be stored in a steel container. If you store it in plastic jugs or leave it in your fuel cell, in about a week a 700 h.p. engine will lose about 20-25 h.p.


Patrick James
PRO SYSTEMS

Patrick, Thanks for the insight on the storage and usage of fuel. It looks like unlike wine fresh is better. I always purchase my brake fluid in metal containers and will now store my fuel in metal containers. The VP containers have a plastic spout is that a problem?

[eric1h]

Originally Posted by Gatorac

369rwhp is 434hp figuring a 15% drivertrain loss. How much were you expecting from that LS1?

The car SHOULD dyno closer to 400whp, also the best dyno pull once the car was "tuned" was 338whp 333tq, WAYYYYY lower than it should have been.

The gas in my fuel cell was over 6-7months old, I'm just wondering if this could have contributed to the low #'s


Also, drained my oil pan, and found gas IN my oil, a long with some metal shavings, I am HOPING this is some left over crap from the old motor and not major damage from the shop running the car on the dyno with gas in the oil and not having proper lubrication. the oil was black and was runny like water!

Can a guy not catch a damn break?

[PRO SYSTEMS]

I would have someone look at your tuneup. If you are still using the EFI system have a look in the pipes..if its black...its rich and that causes loss of power and fuel in the oil. So have someone reflash the computer. I added headers to my GTS Viper and LOST power..until I reflashed the computer. The headers richened the engine up (typically its the other way around on carbureted car). So be aware that a reflash is probably in your future. EFI some folks say is friendly...but to me its a PIA as I know how to read data and tune and engine. Carbs always make more power and are much simpler to tune. This post oughta set the EFI guys on fire. LOL.

Patrick James
PRO SYSTEMS

[eric1h]

Originally Posted by PRO SYSTEMS

I would have someone look at your tuneup. If you are still using the EFI system have a look in the pipes..if its black...its rich and that causes loss of power and fuel in the oil. So have someone reflash the computer. I added headers to my GTS Viper and LOST power..until I reflashed the computer. The headers richened the engine up (typically its the other way around on carbureted car). So be aware that a reflash is probably in your future. EFI some folks say is friendly...but to me its a PIA as I know how to read data and tune and engine. Carbs always make more power and are much simpler to tune. This post oughta set the EFI guys on fire. LOL.

Patrick James
PRO SYSTEMS

Oh boy, here we go....
The good news, the car is a carb setup.

[PRO SYSTEMS]

Simple one then...contact your carb builder. Give him your data and carb serial build # and they oughta be able to give you a jetting change and or air bleed move that should be about dead on on the next hit.

[NZGTRA17]

Originally Posted by eric1h

The car SHOULD dyno closer to 400whp, also the best dyno pull once the car was "tuned" was 338whp 333tq, WAYYYYY lower than it should have been.

The gas in my fuel cell was over 6-7months old, I'm just wondering if this could have contributed to the low #'s


Also, drained my oil pan, and found gas IN my oil, a long with some metal shavings, I am HOPING this is some left over crap from the old motor and not major damage from the shop running the car on the dyno with gas in the oil and not having proper lubrication. the oil was black and was runny like water!

Can a guy not catch a damn break?

Did you spend much time trying to get the engine started after it was fitted Eric or did it pretty much flash straight into life? I have seen bad oil dilution from 3 reasons mainly;

1. lots of accelerator pump use when trying to start a stubborn rebuild,
2. when floats or needle valves are either sticking or incorrectly set, and 3. excessively rich jetting and the engine has done a bit of running.

All of these conditions would have made the car run badly until it was tuned so would have been obvious.

Regards the dyno figures Eric, again I would check what type of dyno the car was run on as not all dynos are created equal. Some brands by nature of the way they work produce higher or lower relative figurs. This is not important if you always run on the same dyno (highly recommend this) but makes a big difference if you are trying to compare your figures with others (who may have run on a different type of dyno).

I would be interested to see the fuel curves and power graphs for the last run that they did on the dyno. Can you photograph and post as this may assist with understanding what is happening.

Kel.