Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[TheBoy]

I'm sure Mantzel do one for the longer plenum. The obvious answer would be to use the right one, if you genuinely believe this modification will offer any improvement for your driving style (it'll be flat low down, impacting drivability, but may offer a near measurable gain at redline). Of course, there is a perfectly good reason that GM put in the complex intake they did after spending 100s of millions developing the car...

A shorter plenum is easily sourced, though the shorter cruise cables aren't so common. Or fit it using rubber elbows.

[zirk]

Must admit I did try a Mantzel on one of my old 3.0 MV6's, in conjuction with a  Courtenay Remap Chip, widdened Throttle Bodies, Ported Inlet Dividers, a K and N standard Panel Filter and more free flowing Stainless Cat Back system, it made a masive improvement at the top end but sucked my MPG out the window at normal driving, which I thought was a bit strange as I already knew the Remap gave better MPG if driven lightly.

Took the Mantzel off together with the KN Filter (MAF fobia) and got me MPG back, did seem a bit more torque'y at the lower end but still seemed to retain the extra top end, dificult to say unless you doing Mods bit by bit. 

[Kevin Wood]

Just like when the multiram system packs up, if you lose the torque at the bottom end you end up revving it more to make the same progress, so fuel economy suffers.

[cem_devecioglu]

any replacement not having a variable inlet system is primitive to say the least..  if its a daily driven car  ,  obviously fuel economy will suffer..  but if performance is the main goal there is a lot to do than a bolt on box.

[minifreek]

So in short, you need the shorter plenums to fit your box...


I will be fitting the longnose plenums to my 2.5 shortnose to aid in getting more torque as I have 4 G cams fitted and the bottom end torque has suffered, I have been told the the longnose plenums will get some if not all the bottom end grunt back... I will suck it and see, if there is a marked improvement they will stay, if not they will be binned and the shortnose plenums will be re-instated....

My engine spec BTW is 4 x G cams, 3.0 lower divider, 3.0 bottom pulley, Vectra Challenge car #20 ported heads, Powerflow exhaust and a heavy right foot