View Full Version : Is there a twincharged a4 1.8t (or any longitudinal 1.8t)?

05-06-2012, 12:47 AM
I've seen some supercharged a4 1.8ts but no twincharged (or even compound). The INA Rotrex looks like it'd work for twincharging, but development seemed to stop around 2009.

Kinda miss my ko3 insta-boost.

Curious because of this:
1.8l twin charged (6262 + vortech = 600hp+)



05-06-2012, 05:08 AM
money, money money! I'm very curious to see what the longevity is of the motor with that setup. It's pretty much maxed out for the type of driving he does.

05-06-2012, 06:25 AM
Do it!

02-22-2014, 08:08 AM

Necro bump with video.

02-22-2014, 10:34 AM
how would you supercharge an I4? like a belt driven procharger?

02-22-2014, 12:49 PM
There's a thread on the 1.8T forum on the vortex for a twin charged Jetta build. It's got a holset feeding into a roots supercharger. THAT is instaboost.

02-22-2014, 01:40 PM
Twincharging is not that great of idea and has been done long time ago though not on an A4 that i know of. The issue is to simplify the build you typically feed the turbo into the SC'r but the SC'r adiabatic efficecy is crap. They rarely break 60% where most turbo operate in the 70% range. The few successful ones I have seen run a supercharger with an electric clutch that turns off and when the turbos spools up but you have to use some trick setup to sperate turbo boost from SC boost since if you cut the SC off it no longer turns and would block the boost or any incoming pressure. When you compound boost it also multpily's how hot it gets which is very bad. The already heated up air gets heated again but by a multiple of the pressure you are running.

With diesel its no issue since there is no knock and you can get the incoming air as hot as you like.

If it were me I would do a sequential turbo build and use wastegates to block the flow to the larger turbo until the smaller turbo has made enough boost to spool it and then block the smaller turbo. Bigger diesel trucks work this way but the trick is to keep the smaller turbo from making boost and allowing the larger to simply blow through it. You wanna freak some people out pull up the to line and let them hear 2 turbos spool.

02-22-2014, 01:50 PM
Also rotrex and Vortech (or any centrifugal SC'r) does not really help out the way a twin charge setup is supposed to. Basically in a twincharge setup you use a SC'r that gives you instant boost which aids in spooling the larger turbo. Think of it like having a 1.6liter running 15psi. Basically you have turned the 1.6liter into a 3.2 liter which allows you to spool the larger turbo like a 3.2 liter engine. The rotrex or any centrifugal does not make instant boost like a roots or twinscrew does. It creates a linear power band that builds boost as you rev. They are more efficient though.

Look at the dyno above. They were making 520AWHP which they easily could have made on just the 6262.

Demonmk2- It really does not hurt the motor if it is ran like it should be. HKS made a twincharge setup for 1988-89 Supercharged version of the Toyota MR2 keeping the stock SC'r and turning it on and off based off TPS input and boost. That kit never had issues with longevity and took a SC'r 1.6 liter making 145hp all the way over 300hp on a completely stock block. At part throttle it made no boost while driving up the interstate or around town. However once you mashed the gas it would take it off.