Your thoughts on my slow car
- Thread starter T-top87GN
- Start date
BLACK6PACK
1 sec reaction King
- Joined
- May 24, 2001
Sorry about hijacking your thread. When it comes to fuels it can get rather complicated.
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
BLM is good, and I personally like to see it a hair lean down low
Shifts pretty normal
And you have a nice big and open exhaust
You still can crank it up a bit due to your fuel pressure going up and following your boost psi.
But still, with all your mods and that PT51 pushing 20psi you should be running much faster than that.
Hope to hear back that you found the missing link.
Shifts pretty normal
And you have a nice big and open exhaust
You still can crank it up a bit due to your fuel pressure going up and following your boost psi.
But still, with all your mods and that PT51 pushing 20psi you should be running much faster than that.
Hope to hear back that you found the missing link.
Bandit,
Keep in mind O2 readings by themselves are just a rough approximation to use for tuning. For example, if you are seeing knock and your O2 readings look like you are lean, then raising the fuel pressure might be a good thing to try. Even if there is no knock, sometimes raising the fuel pressure is better on some cars and sometimes lowering is better and you would only see this reflected by the 1/4 mile times (EGT or wideband O2 would also help) and trial and error may work best. Most people start with the fuel pressure recommended by the chip and work there way from there, usually only a couple pounds or so.
Also, as long as your fuel pressure regulator is working accurately you shouldn't have to change your fuel pressure everytime you adjust boost. Fuel pressure should increase with boost accordingly, that why people put fuel gauges on the hood so they can verify this. The only time you should have to increase fuel pressure with boost is if you have too little injectors and they are already being pushed. Keep in mind its important to have a chip for the boost range you will be using. Running too much boost on a street chip there's the possibility there's not enough fuel programmed into the chip and running too little boost on a race chip means there could be too much fuel. You should not have to adjust fuel pressure to make up for this.
I still think you are running decent times if you are using a street chip. A race chip and 25lbs boost you'll be in 11's with a good launch.
And BLACK6PACK, I don't see how your post has anything to do with higher octane making less power. If anything the statement backs up that higher octane makes the same power as lower octane. The advantage of the higher octane is that you can run more boost and/or more timing without getting detonation/knock. If you keep the same timing/boost with higher octane there is still a spark and the fuel ignites so you will still get the same power you had with less octane. Its not like the higher octane fuel doesn't ignite or anything, the spark assures that it does. Like stated, octane only has to do with the tendency to pre-ignite.
As far as MOST higher octanes burning slower..... on the flip side many burn faster. If you don't know which ones do what then its useless. It could be that the gas VP recommends for turbocharged cars and a lot of people use, C16, has a higher burn rate then normal since turbocharged cars tend to be lower compression cars and would benefit from a faster burning fuel before all the boost kicks in. Or maybe not, but without knowing for sure I wouldn't speculate one way or another.
Its nice to have a good discussion once in a while as a break while at work.
Keep in mind O2 readings by themselves are just a rough approximation to use for tuning. For example, if you are seeing knock and your O2 readings look like you are lean, then raising the fuel pressure might be a good thing to try. Even if there is no knock, sometimes raising the fuel pressure is better on some cars and sometimes lowering is better and you would only see this reflected by the 1/4 mile times (EGT or wideband O2 would also help) and trial and error may work best. Most people start with the fuel pressure recommended by the chip and work there way from there, usually only a couple pounds or so.
Also, as long as your fuel pressure regulator is working accurately you shouldn't have to change your fuel pressure everytime you adjust boost. Fuel pressure should increase with boost accordingly, that why people put fuel gauges on the hood so they can verify this. The only time you should have to increase fuel pressure with boost is if you have too little injectors and they are already being pushed. Keep in mind its important to have a chip for the boost range you will be using. Running too much boost on a street chip there's the possibility there's not enough fuel programmed into the chip and running too little boost on a race chip means there could be too much fuel. You should not have to adjust fuel pressure to make up for this.
I still think you are running decent times if you are using a street chip. A race chip and 25lbs boost you'll be in 11's with a good launch.
And BLACK6PACK, I don't see how your post has anything to do with higher octane making less power. If anything the statement backs up that higher octane makes the same power as lower octane. The advantage of the higher octane is that you can run more boost and/or more timing without getting detonation/knock. If you keep the same timing/boost with higher octane there is still a spark and the fuel ignites so you will still get the same power you had with less octane. Its not like the higher octane fuel doesn't ignite or anything, the spark assures that it does. Like stated, octane only has to do with the tendency to pre-ignite.
As far as MOST higher octanes burning slower..... on the flip side many burn faster. If you don't know which ones do what then its useless. It could be that the gas VP recommends for turbocharged cars and a lot of people use, C16, has a higher burn rate then normal since turbocharged cars tend to be lower compression cars and would benefit from a faster burning fuel before all the boost kicks in. Or maybe not, but without knowing for sure I wouldn't speculate one way or another.
Its nice to have a good discussion once in a while as a break while at work.
Mike;
d00d I am just as confused as you are.
Murphster;
I have always tried to maintain an O2 reading of around 770-780 at WOT and you know what? My car has always been slow. I guess I need to ignore those numbers and crank the boost till it knocks?
Ed;
That would be a great idea except that my speedo cable is messed up and I didn't know till I got to the track. So I have no MPH reading except the ones on the time slips. Thanks for reminding me I need to go fix that speedo cable tomorrow before I hit the track Friday.
Don't worry about hijacking the thread guys. This kind of discussion is always welcome as far as I'm concerned.
d00d I am just as confused as you are.
Murphster;
I have always tried to maintain an O2 reading of around 770-780 at WOT and you know what? My car has always been slow. I guess I need to ignore those numbers and crank the boost till it knocks?
Ed;
That would be a great idea except that my speedo cable is messed up and I didn't know till I got to the track. So I have no MPH reading except the ones on the time slips. Thanks for reminding me I need to go fix that speedo cable tomorrow before I hit the track Friday.
Don't worry about hijacking the thread guys. This kind of discussion is always welcome as far as I'm concerned.
BLACK6PACK
1 sec reaction King
- Joined
- May 24, 2001
murphster,
I'm always up for a good discussion and learning new things, and I agree that without knowing the exact chemical makeup of a specific gasoline its hard to tell if it burns slower or faster. In my post from the chemist the first paragraph clearly states that..."If an engine is not detonating, higher octane WILL MAKE LESS POWER. Use the lowest octane without detonation." Now while this isn't true 100% of the time its still a good rule of thumb.
Take a car in street trim with 93 octane and see what it does in the 1/4 mile. Then try 10 different high octane gasses with that exact same street setup and I would bet that the 93 octane would be faster than 9 out of the 10 high octane gasses.
I'm always up for a good discussion and learning new things, and I agree that without knowing the exact chemical makeup of a specific gasoline its hard to tell if it burns slower or faster. In my post from the chemist the first paragraph clearly states that..."If an engine is not detonating, higher octane WILL MAKE LESS POWER. Use the lowest octane without detonation." Now while this isn't true 100% of the time its still a good rule of thumb.
Take a car in street trim with 93 octane and see what it does in the 1/4 mile. Then try 10 different high octane gasses with that exact same street setup and I would bet that the 93 octane would be faster than 9 out of the 10 high octane gasses.
