13Whp 6 ft/lb gain.

 

I want the modded intake tube! And I want it now!

 

So how did you go from 318whp to

"full stock best pull was 349whp 376ft-lb
with intake elbow 362/382 ft-lb"

If only 13whp came from the intake???

JG

 

Temprature, it's no longer power robbing hot in texas

 

I believe the first numbers were from a few months ago. When he was working on the intake he went to the dyno did a run with the stock intake then switched to the new intake then did a run back to back. I'm pretty sure he did it this way cause you are gonna get more accurate results as the parameters are all gonna be the same since the dynos were pretty much back to back. Hence the 362-349 is the 13whp gain he is talking about. The 318 to the 349 I'm sure are the parameters I'm speaking of as now the weather is alot cooler.

 

Vance is correct the 318 pull Was just to get a base line in the summer. Now it's fall 349 is a BONE stock baseline.

You can see how much power 30 degrees OAT stole from the car

I would love to get some pulls in the dead of winter when OAT is ~30's but with my current cat issue it's just not gonna happen.

 

I get it now, wow 30Hp is not bad from just good cold weather. I've noticed this too in both of my cars (Jag STR and BMW Z3 Turbo) cold weather is way better for the FI and even any NA engines, for sure. The air is far more dense, more O2 per square inch...

I was very lucky today, I thought I had a broken water hose under the SC, but as I took the engine's cover off, I started the engine and using a big screw driver moved some of the watercooler's hoses out of the way, so I could see better, then I placed a broom stick on the driver's seat and made it rest on the gas pedal and moved the seat just enough to make the engine rev @ 2000rpm, then I looked again and coolant was coming out from the end of the two small hoses that attach to the thermostat housing. So I cut them about 3/4" short and clamp them back and now, no more leaks...!!! YEAY!

My 3# Pulley is on its way, and today I changed my thermostat with the "low temp" one sold by EuroToys, now I really need to look into this CAT delete operation.

JG

 

I'm not sure how the widebands are going to feel about the deleted cats I'm not 100% sure the PCM will cope with the lack of a difference between the upstream and downstream O2's You can run the risk of throwing the car Into limp mode from the PCM freaking out and not finding the cats. You might be venturing into uncharted territories.


-Just food for thought

 

+1

 

Quote:

Originally Posted by jag79

+1

To avoid this problem, you can buy O2 spacers, much like the spark plug non-foulers and install them with the second O2 sensors. They are cheap, and widely available. This is simply to fool the computer. By restricting the air flow through the sensors. You can even install more than one per sensor, if for some reason one can’t do the trick. I've seen people use as many as 3 in one install. By the way just to make it clear, this mod is only needed in the after CAT sensor (one on each side of course).

I did have one of these spacers in my Z3 turbo when I first did install the turbo. I took the Cat off and made my own strait 3" pipe with just mufflers at the end. No resonators or Cats, I was shooting for the max flow possible. But after I talked to my tuning guy NickG, he told me to just take off the second O2 out completely, he says the computer will ignore it, since there is no Cat in the system anymore... Now this might not be the case for the Jag's computer. But It could have been too, that it had to do with my custom made DME/ECU programming? I’m not sure, so I'll ask him anyways.

 

you can also either buy or make your own mil eliminators for the post cat 02 sensors.

I gutted the cats on my xjr and made a pair for each o2 sensor.

 

Yes another idea indeed. Which colour wire carries the signal? And how big of a resistor? voltage under 300mv? thanks for sharing this great info blaksplash.

JG

 

i used the info found here

it takes 1 each of these per side, so 2 each total. i got mine from radio shack

1.0uF 20% dipped tantalum capacitor
1.0 M Ohm 1/4 Watt 5% carbon film resistor (or 1/2W)

Unfortunately i did all that about 2 years ago so i can't remember exactly which wires were what. and the xjr is long gone so i can't check it.

But, if i remember correctly, the xjr's o2 sensor wires were 2 black, 1 gray, and 1 white. I used a voltmeter and some trial and error with an obd2 scanner on a laptop to check the readings.

 

Absolutly you can remove O2's out of a tune. But we are back to square 1 who can do it?
We are like Juan Ponce De Leon looking for the fountain of youth!

 

Buddy we are not deleting the O2 sensors. We are fooling the computer, by making it believe that everything is where is suppose to. This can be done either by installing the spacers so the air flow is less than an opened exhaust would be; then the computer thinks the Cats are there, or you can place a resistor in the wire that carries the signal to the computer, then the computer senses the signal, being weak, as if there was “less air” flowing through.

The Cats do the real chemistry job here, in simple words they remove the unburned gas and most of the waist that does and doesn’t ignite in the engine. But to the computer the only way to tell so is by reading the slower smaller amount of air going, that’s ultimately slowed and restricted by the Cats when installed. The sensor doesn’t altered the Chemistry of the gases going through that’s done by the Cat itself, the sensor only feels the air (small, slow flow), and by that its hot or cold temperature, and because of this, it then knows the concentration of oxygen in the mixture. There for the computer knows the Cats are installed or missing.

 

http://www.youtube.com/watch?v=QcZHVDcKfdM

here is one of the new dyno vids, from the 11 pulls.

 

I thought the 2nd O2 reads the amount of O2 that is left in the exhaust after it passes through the cats. I don't understand what hot or cold air has to do with anything?

 

Thanks for asking, a great question by the way. The more oxygen involved in the combustion the hotter the air will be... If you ever saw a burning flame (for example while using a soldering torch), up close the very tip with the blue color is where the hottest spot in the whole flame is located, that’s because this is where the most oxygen and fuel are reaching/reacting with each other, in this case the propane and the oxygen. This is why a “lean” running car will make more power, but it will too run Hotter!!!!!!. Also keep in mind the combustion of a "rich in fuel" running engine (higher mix of fuel vs. oxygen) will cool the exhaust gases too, and vice versa. This is known in the motor world as running “rich” or “lean”. It’s essentially all about the ratio of fuel and Oxygen at the time of ignition, that interestingly enough can be measure if you think about it, by just knowing the temperature of the (exhaust) gases after ignition, and since the computer has already pre-programmed tables with some specific temperatures that tell it what ratios of fuel/oxygen to the engine mean rich (cold) vs, lean (hotter). There for to “fine-tune” its efficiency the computer needs to constantly know the current temperature from the exhaust gases on real time, so it can then, recalibrate accordingly for all the different conditions, and achieve the most ideal ratio! The CATs will keep things clean.

So this is the real function of the O2 sensors, by reading the temperatures of the exhaust it knows how much O2 and fuel are being mixed...is simple (yes), but it gets the job done!

 

Love it!

 

As far as I've read, the O2 sensors do NOT measure temperature. They measure O2 (thus their name).

If you believe otherwise, please provide evidence.

The O2 amount is fine for closed loop control.

In engines where exhaust gas temperatures are needed, temperature sensors are fitted (as well as O2 sensors).