GTM Performance Engineering: GTR Manifold Conversion

Mike@GTM

Yes, it will work with the 7AT.

Considering that the OEM GTR upper plenum is $958 by itself, are you really that surprised?

The stock fuel rails do not work with our lower manifold. Also, the inside diameter of the stock rails is quite small.

The throttle bodies are the same for both the VHR and the VR38DETT. That said, they are in different locations and since we make our own turbo kit as well as this conversion, it's only logical for us to have the appropriate piping available for both to work together.

Thanks.

For your first question, that would be assuming that the port is a perfect circle, which it is not. That said, the cross sectional area of the port is 1669mm^2.

For your second question, the stock fuel rails are not compatible with this manifold. The crossover is not long enough to span the width of our lower manifold. You could cut the crossover and mounting tabs off the factory rails, weld on A/N fittings and new tabs to make it work, if you really want to.

The thing is, the inside diameter of the factory fuel rail is surprisingly small. As you can see below, we cut the crossover to get a better look at things and they are very small (~5mm =~ 0.197"). While the inside diameters of the rails themselves are 11.25mm as shown in the last picture, the restriction is in the feed lines and crossover.


That is precisely why we offer the various components for the conversion separately. You can purchase the lower manifold by itself along with one of our fuel rail setups (either -6 or -8). For the hardware, it will come with the adapter manifold.