so the last plenum had a vacuum chamber that shared the vacuum between both plenums. the problem is that the iac fed into this chamber, and when the iac opened it was jacking up the map values and the iac would just keep opening more and more, untill the vacuum looked right for an idle....the end result was a 2500rpm idle.
to fix this, im making a whole new plenum. in this the vacuum will come from a combined chamber of both plenums. the iac will feed into a seperate chamber where there will be an individual tubes going to each velocity stack. here is a paint diagram....
and when my camera decides to load ill show you the pics of my new supplies
__________________
87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
__________________
87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
Actually, they way you have the picture you should use that for IAC/everything no problem. My guess the last plenum had a leak or the MAP was only reading one side.
The MAP and brake booster need strong vacuum that's not shared with anything.
If the TB you are using does not have a built in IAC, then running an external one that feeds both sides is recommended.
If you are going custom I'd keep the plenum's seperate with the TB blades. Then just make a connection on the back/center of each plenum with a T that goes to the brake booster, and another for MAP farther away from that one, then a smaller one for whatever else like FPR.
__________________ New 2010 project (click image)
1994 3100 BERETTA. 200,000+ miles
16.0 1/4 mile when stock. Now ???
Original L82 Longblock with LA1, LX9, LX5 parts
Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.
it has an iac in the tb, but the problem is getting it to feed both plenums equally.
the map was feeding off the same chamber that fed everything else. in other words it didnt get acurate readings.
i see what your saying there, make it true dual plenums and then run a connection between the two for the map, one for the brake booster and one for fpr and one for pcv
__________________
87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
I just found that, haven't looked at it all that much but has some cool stuff I thought you might get some ideas from maybe?
__________________ New 2010 project (click image)
1994 3100 BERETTA. 200,000+ miles
16.0 1/4 mile when stock. Now ???
Original L82 Longblock with LA1, LX9, LX5 parts
Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.
__________________
87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
Last edited by merlot566jka; 12-26-2007 at 10:53 PM.
Reason: i need a cnc machine
Thats one of twm's injection systems on that manifold, it has the same flange faces as a set of tripple barrel webers.. I have been trying to find a cheaper set of the webers or zenith's for a couple of years now.. I had that plan after I built my first manifold, little did I know thay actualy made them..
Linear Mode
