Can somebody splain why, cause I 'm not quite sure I understand. The last time I went to the1/8" mile strip, I removed the air cleaners and the car ran about 2 tenths slower than with them in?



See car mods below

 

What were you using for an air filter housing? My first shot would be turbulence of higher temp air ingested, or a combo of both.

 

Removing the cleaner leans out the A/F ratio of the car. If you had enough fuel before and removed the filter it could have caused a leaner condition than you wanted. Just a possibility.

 

My car has the stock (restricted I know!) dual air filter plastic intake system + K+N filters--modified MAF (Bosch).

One other person had the same possible explanation, that with the amount of airflow with the filters in place --at WFO--the amount of gas being dumped at max matches the amount of air coming in.

With the filters removed there is an increase in airflow volume and even thought the Maf sensed that, it was pumping at max, which he said means that possibly a slight increase in fuel pressure at the AFPR, or in the chip programming, would be able to take advantage of the increased air flow and keep the correct air/fuel ratio.

Now, if that is so, I need to figure out if this IS what is happening.

I guess the first and easiest thing to do is check the fuel pressure and try increasing it and see if it runs any better?

Anybody have any other suggestions?

Thanks,
Craig

 

Can you explain how that happens if the air filters are upstream of the MAF?

As far as the original question, you can't compare the two setups fairly with only two runs. There are two many variables involved. You need to make several runs with filters, and several without, and compare them to try to reduce variability.

 

Uhh, sucking pre-heated air from the radiator?

You supposedly gained a minor power increase from losing the intake friction of the air filter. But you also pulled pre-heated air into the engine. The loss due to heated air (especially the hot air in the engine bay while you are in the staging lanes, then on the line waiting for the tree) is more than the power gained from the filter delete. You didn't flush the pre-heated air from the engine bay until you were a good distance down the track (when there was enough air speed to flush the hot air). That's one reason why cold air intakes are better at the track.

Hot intake air = less power.

That's my guess.

 

Well, for every 11 degrees that you drop intake air temperature, you pickup between .5 - 1.0 % more hp.

 

The air intake source was the same--I did not remove the plastic housing--just the filters and resealed the oem plastic housing, so the air would still be routed past the ambient air temp sensor and through the MAF.

 

The stock OEM dual filter housing--just removed the filters and resealed the system.

 

As well as playing with the fuel pressure, I think I'm gonna hook up my scanner--make a few runs and see if it shows the car leaning out--both with and without the air cleaners in place.

Thanks for all the info--given me a couple things to think about--will post after I have more info!~

 

Hey Craig, have you done any chip tuning yet to that car? I know its nowhere near stock.

If you haven't.. PM me, maybe I can burn you a chip that could help you out, plus I can pull some data and see what your car is really doing.

 

It has an Ed Wright chip right now.

I am supposed to get a Mikeeee chip next weekend, before he sells all his rig to buy a clutch for his car.

 

Hotter air + a "Slighty" leaner condition = just enough to trip the knock sensor.

Knock sensor sends signal to ECM which retards the hell out of the timing.

Power loss.....


Case closed....

 

Self installed toggle switch that temporally disables knock senser had knock senser off for 2 of the 3 runs.

 

Hey Craig, its been awhile..
Im not sure about the sequence of things.
But it sounds like you are comparing two runs that you made recently to previouse runs you made in the past.
Did you run the these times with and with out filters during the same outing?

Rob

 

Hey Dude! Where U been?

All runs were in the same 3 hour time span.

2 with
3 without
4 with

 

I have been working 6 days a week 10 plus hours a day trying to get caught up. (wich will probaly never happen) I was told that we are fixin to back to 5 days a week when we do I'm goin to do some catch'n up with you guys !

Back to trying to decipher your delima.
What kind of filters you running ?
Did your trap MPH increase or decrease or just your time drop?
I was thinking of different possibilities and since no one has said it yet .
I was wondering if you gained some horse power/torque out of the hole enough for it to cause a 2 tenths of traction loss ?

 

 

modded 5.7. It isnt stock. TRACTION sounds like a problem. Try some DR's with and without the filter and i think they will be pretty much the same. Thats why they have bracket racing so you people with consistancy have a better chance then people with 5,000,000,000 horsepower.

My $0.02

 

See post immediately above

Had the Nittos DR's on--hooking up very good--low 1.8 60 ft times!--which I'm told for a mid 8 sec 1/8 mile car is pretty good?