Solved problem...catalytic converter

[V6POWER]

I took off my 'high flow' (yeah right) cat. and reinstalled my test pipe and my car runs like it used to. When the cat. was on I was running very rich (O2s=890s-830s; EGTs=1460s), could not build boost above 22#, and I had lost .4/3 mph in the 1/8 mile. I just did a 1/8 mile street test run and the O2s=840s-780s and the EGTs=1590s. I can now build boost easily at 23.5# I still have to do a little more tuning because I got 1.2* retard. Now I have to get back to the track to see if I regained my .4/3 mph. Thanks for everyones' help.

 

[turbo buicks]

thats weird b/c my dads vette mechanic said he had a 5.0 stang that lost torque w/o a cat. he said the cat helps the turbo build boost quicker and it needs more backpressure so i dont lose torque, LOL i dont think he knows what a turbo is.

 

[V6POWER]

You answered your own question...a vette mechanic who owns a mustang

 

[turbo buicks]

LOL

 

[UNGN]

Originally posted by turbo buicks
thats weird b/c my dads vette mechanic said he had a 5.0 stang that lost torque w/o a cat. he said the cat helps the turbo build boost quicker and it needs more backpressure so i dont lose torque, LOL i dont think he knows what a turbo is.

Time for your dad to find a new mechanic

 

[turbo buicks]

well its actually the vette mechaincs assistant/worker /employee guy. the vette guy is actually pretty knolwedgable about vettes. he owns like 2 or 3

 

[Darkside]

Hey,
Sell me that cat cheap, I'll gut that kitty!

 

[V6POWER]

I need it for emisssions.

 

[scottyb]

Originally posted by UNGN
Time for your dad to find a new mechanic

Ditto that.
My car gained 5 tenths in the 1/8 when I removed the 15 year old cat. clogger.

 

[Chuck Leeper]

"HIGH FLOW CAT"

If we do the math, we can understand why a single, cat could cause the car to slow down.
24# of boost is 1.6 atmospheres at sea level. The engine already sees 1 atmosphere and you have added 1.6 more.
To keep the math uncomplicated, assume the boost was 15.. now we have 2 atmospheres of air going thru the engine. Assuming the engine is 231 CI, we are now dealing w/ airflow to support a 462 Ci NA engine. I this case, it was more than 2, more like 2.6 X 231, for a total air flow for a 600Ci engine, naturally aspirated.
That's why the single cat,"hi flo", or any other, was acting as a restriction..
Bottom line is, if you want to run the boost, the system would have to be sized to handle the airflow..
Imagine what it would be like to put a cat system on a 400Ci turbo/blown engine!!...

 

[V6POWER]

Chuck--Thanks for the great explanation.