Contour Enthusiasts Group Archives Forums Modifications Duratec Performance SECONDAIRES - Some interesting findings

For anyone who has pinned or removed thier secondaries, have you noticed much loss in MPG. I am considering removing them right now in conjunction with getting the new lower manifolds and injectors from BAT, but I am worried that I will very significatly lower my milage. Thanks.

Pinned - No change in mileage over 5 weeks.

Do you have a returnless system? The BAT's lower, injectors, and rail is for a returnless system.

I liked them pinned, but keep in mind I am nowhere's near stock. Plus have 10.25CR and aggressive cams. (I.E. I'm setup for high rpm HP, not the compromises the stock cams/setup is designed for)

I adjusted my stop in approx. 3/4 of a turn last night. There was no noticeable improvement via the butt dyno. Possibly, the PCM needs to learn the new air flow. Couple of comments... Is anyone doing this adjusting with the upper still on? I tried and dropped my wrench, at which time it became absolutely necessary to remove the upper intake for retrieval purposes. It sure made adjusting the stop a lot easier with the upper off.

Brad Noon-How did you remove the shafts? They're swaged on at the linkage end. Did you grind/cut them off? I assume after you get one end released they just slide out....

Doesn't matter, swap your stock fuel rail if you have a return system car. Unless you have a '95 car with side feed injectors, that's all you need to do. The side feed injector cars will have to keep their stock injectors on the new lower... if they fit.



Once all of the butterflies are removed, the rails just slide out with a little wiggling. I didn't want to damage the shafts, so I hit them with a heavy dose of carb cleaner to remove most of the carbon from the rails prior to pulling them out.



Even with the 3 liter with the secondaries removed I've been getting 24-28 MPG. Not bad in my book.

Just for interest added to the 'dump the secondaires'.The 2002 BMW 7 Series,with two new V8 motors,has an intake runner length control system that changes the lengths from 9.1 > 26.5 inches.Very exotic system.Be interesting to see the BMW owners trash it for more power....right! :p

Those wacky Germans, what will they think of next? In about 10 years, every BMW will have the variable intake runner system. Pretty darn cool.

The secondaires are a 'runner length' control system! :rolleyes:

Here's a pic. Dont help much but thought I would post it.



We did just what brad said except the bols we used were very tight and we just used some silicone sealer to stop any leakage of air. Can't say if I noticed any MPG loss because I did this at the same time as the S/c. All I know is the car makes power way down low but that is prolly cause the air is getting through @ lower RPMS due to the forced air coming in from the S/C.

Did a little further testing yesterday. There is a noticeable improvement, albeit small, by cracking the stop open approx. 3/4 turn. Gather it took a little time for the PCM to relearn the new airflow. Gains are most noticeable between 2500 & 4500 RPM's, with better throttle response and pulling power. Fuel mileage was unaffected, possibly better. Got 33.2 mpg (Imperial) 27.7 (USG) combined highway/city on a 300 mile trip. For power comparison purposes this gain is about half what I got from the SVT t-body upgrade.