just ordered a maggie and wondering should I leave the headers on?
I am reading that headers cause boost loss--true?

 

Yep, you lose a little boost. Most folks with headers step down on pullies to get it back.

 

Yes,more air in more air out. Swap out for a smaller pulley to make up for the loss in boost.

 

,TOTALLY!!

 

 

Not "boost loss" in the same sense as turbo's (which come after the headers), which occurs because of the velocity loss of the bigger inlet pipe.

I actually think you wouldn't lost much with a maggie and stock heads, as the boost loss really occurs on the intake/cylinder. With AFR 255/70cc heads + cam, and a stock maggie setup - my expected boost of 7PSI ended up being 4PSI. We all kinda slapped our heads and went "DUH" (even though we informed maggie of the setup and asked them to pulley accordingly). Smaller front pulley's didn't do the trick, so it had to go out to Cali for a rear pulley swap. When I upgraded to the 122 case - we made SURE they pulley'd the rear so I could max it out @ 14lbs with a 3.2 - currently running 12lbs with a 3.3 (and a STOCK BOTTOM END).

So, KEEP your headers - smaller exhaust creates the flow bottleneck in clearing the cylinders that will kill off some power. An engine is an air pump - the more air you can get through it - the more power you can make. You MUST be able to effectively "exhaust" the additional air you're forcing in with a blower.

Another note: BEWARE THE CLOGGED CAT. After about 4K mi on boost with the (supposed) high flow cats that came with the SuperMaxx headers, one clogged solid, the other was on the way (clue, ran like a$$ and boost was up to 16lbs - another demonstration of the facts stated above - I wasn't getting MORE boost - I was impeding the clearance of the cylinders and getting a BACKUP). I ended up gutting the cats. Car got like 25% LOUDER, but I don't have to worry about killing the cat anymore...

Rick

 

thanks for the post RicK

 

How does the cat get clogged?

 

i think it melts and caves in

 

With headers, boost "loss" is a good thing, means that the A/F isn't getting backed up in the plenum.

You will get a similar "loss" in boost if you add ported heads.

 

Knkali, High boost is not always an indication of more power achieved, it's usually an indication of ristricted and poor airflow. I used to own a 93 Mustang cobra procharged and intercooled on a built 302 motor. At full throttle with 1 3/4 super comp headers, catless set up and 2 1/2 cat back dynomax tips, the boost gauge showed 17lbs of boost.

I swaped the motor and went with a full race 331 stroker motor, fully ported canfield heads, solid roller cam, and same exhaust and blower pulley. Boost went down to 11 psi due to efficiency, and the motor generated 105Hp and 80lbs of torque over the old set up. Yes boost was lowered, but due to efficiency of the new set up, hp and torque sky rocketed. HEADERS are a must with a supercharged application.

 

Feel'n good guys --thanks for the info. Looks like the AR's are staying on. Now looking for the hood at a good price.