Originally Posted by gabe3d

Even though many users have previously posted about the Cosworth Intake Plenum not performing well on non-FI car, no one has really done a good before and after test. So a few months back I took the plunge and shelled out the premium to get one to hopefully gain some power over my Motordyne 5/16th and MREV2.

As expected from cosworth and any premium items, Build quality, packaging, and looks were top notch.





Installation of the unit was straight forward, other than three things.
1. My box didn't come with a manual so I had to get one faxed from the vendor.
2. Installing the gasket for the carbon cap is really a pain in the butt and would appear to be very susceptible to leaks.
3. The bracket on the passenger side carbon cap is not meant to last. It broke off right after I started the engine. Luckily it's not vital for the operation of the plenum.



After installation, the manifold definitely looks a lot nicer than the stock setup and clears the strut bar much better. Please ignore the dirty engine bay.



Aesthetics aside, how did it perform? Driving the car around a noticeable power loss can be felt down in the lower and mid range. I was quite disappointed to say the least but I never trust my butt dyno so off to the dyno it went. Below is a series of two different test comparing the Cosworth on a fully NA engine.





Based on these tests, it is apparent that the Cosworth is not suited at all for my application so back to the Motordyne setup it is. But I must say that the one performance advantage the Cosworth has over the MD is the ability to sustain power pass 6500rpm... to be continued.

Originally Posted by lucid215

Can you run the cosworth with the plenum spacer

Originally Posted by WhosUrBuddiee

Also keep in mind Cosworth no longer sells the sexy cf caps. They raised the price and now give you cast aluminum caps.

Originally Posted by c_morse

No. Cosworth replaces the upper and lower plenum. Plenum spacer on a stock intake manifold goes between those two parts.