Seing double?, Now tested double D-jet performance! Options

[larss]

Anybody tried double D-jet air boxes and TB before?

(IMG:http://www.914world.com/bbs2/uploads_offsite/www.lsmteknik.se-10787-1389339349.1.jpg)


/Lars S

[Brian Mifsud]

So what do you gain with Double Throttle Bodies and Two Plenums?

I can understand that if I bumped the Stock Displacement of a 2.0, I'd get higher vacuum at the same RPM (making no changes to valve and cams). I'm assuming that this higher vacuum gets out of the range of the MAP sensor so the computer doensnt' get signal to send MORE gas?

If I split the airflow into two seperate throttle bodies, I can see how Pressure-Drop or Vacuum would be reduced quite a bit for the same airflow since I'm flowing only to 2 cylinders.

Is this the idea?

[larss]

So what do you gain with Double Throttle Bodies and Two Plenums?

To be honest - I dont know yet. This is an experiment I set up, could not resist to make it since I had all the stuff and it is a super easy modification (so far).
The Engine is a 1911cc with standard 1,7 heads and std 1,7 D-jet, not started with the double arrangement yet. Its a street car, Im not looking for race performance.

The theory is thet the larger displacement needs more air (and fuel) and hopefully the two 1,7 airboxes and TB's and can give some more air. Fiddeling with the MPS, CHT and fuel pressure will bring more fuel. I may have used a single 2,0 TB with manifolds instead if I had one.

If I split the airflow into two seperate throttle bodies, I can see how Pressure-Drop or Vacuum would be reduced quite a bit for the same airflow since I'm flowing only to 2 cylinders.

Yes lower vacuum sensed by the MPS means more fuel as far as I understand.


/Lars S