View Full Version : Scetchs I told you about Rob

Captain Blacki McBlackerton
05-20-2005, 05:10 PM
Here are some very early sceths of 2 intake manifold ideas I came up with. They have pros and cons but I'll post them later b/c I have to get back to work. Warning it's in pencil and I did this pretty fast so there's mess ups

http://img5.imagevenue.com/loc143/th_d74_lastscan3.jpg (http://img5.imagevenue.com/img.php?loc=loc143&image=d74_lastscan3.jpg)

05-20-2005, 05:19 PM
#2 wont wrk. The runners would have to be 100% even in length and have a very long straight tube prior to the divider, otherwise, you would have 1 runner that is shorter than the rest getting most of the air and running lean as shit. Also, if you dont have the straight tube, the air will favor 1 passage more than the others and the same result will happen.

#1 is proven. Plenum/runner designs are the most effecient. I've been stirring an idea for making one in my head for a while now.

05-20-2005, 06:08 PM
andy is right, you need a plenum to help to evenly distribute the pressure and air equally.

tapered plenums help to keep the back cylinders from getting starved at the beginning of WOT, but once the plenum is fully pressurized, its all fair game between tapered and equal sized plenums.

#1 is a good design. :thumb

Captain Blacki McBlackerton
05-20-2005, 11:37 PM
thanks guys I was in such a rush I didn't realize my spelling was so bad.I was thinking for both an electronic individual throttles but due to the weight and programming issues related to it. The main reason I came up with the idea was to be able to near perfectly tune each cylinder verses an overall tune. To do this right it would probably have to be a race only manifold b/c I would plan to use 4 o2 sensors one tapped to each exhaust runner before the turbo. But I don't know if the would hurt the exhaust flow or if it would quickly nuke the sensors. This is just an idea I thought up on my way to Dallas yesterday. It came about because of compression tests done to each cylinder and that they are usually different and thought that ifyou reach the limits of tuning with injectors you could do it with the throttle bodies. I'll admit I'm still a noob when it comes to stuff like this, like for example the length of throttle bodies to use and running the cables etc. I just wanna see how close I am to something really worth building. So far from what I've read it seems pretty good. Thanks for the feedback guys

05-21-2005, 02:22 AM
But I don't know if the would hurt the exhaust flow or if it would quickly nuke the sensors.

the latter. Having the O2s so close to the head would end up frying them. It's way too hot that close to the engine for O2's to be of much use.

05-22-2005, 05:45 PM
No but 4 EGT's might not be bad and would probably be better than O2's for tuning.