VW Vortex - Volkswagen Forum banner

Cis Turbo. Need help tuning

4K views 2 replies 3 participants last post by  RevolutionMotorsportsCt 
#1 ·
This is my first post ever on any forums.. I'm honestly stumped with this car though and can't seem to pull any answers off posts from years ago so here it goes. I took my 1980 rabbit with a 1.5 cis and turbo'd it this winter with a Garret t3/t4 out of a Volvo 240. I rebuilt the turbo, spins beautifully. Kept the factory wastegate (seems to be working well). (I've also wired the wastegate shut to see if it was my problem and it didn't boost anymore than before). Max I get for boost is like 4 pounds. Also doesn't start to build boost until like 3500 rpms, then its cutting out and popping at 5. Now to add to my problems I can't figure out where I should be setting my timing or where I should be setting my air/fuel ratio adjustment on the fuel dizzy plate( I've adjusted both everywhere). It seems like the more retard my timing is boost builds quicker but the car is sluggish and when I advance it I can only get one bar at like 4 grand and still runs out of fuel or something around 5 grand. This car ran beautiful and would rev out to 6+ no problem before I put a snail on it 🙄. I also don't know if the wur check valve is facing the right direction or if it is even needed on a boosted setup. Or if my vaccum in general is setup correctly, like my pot on the distributor where I left the back open but ran vaccum on the front. I drew up a diagram for my vaccum lines but I can't seem to tag it with this post. I'll try again later. Any pointers or help would be appreciated. I can take photos of anything that would help. Thanks
 
See less See more
#2 ·
Diagnosis is what you need to learn. You cannot just throw parts at a engine and expect it to work.

So, what is your fuel pressures like? Do you have a gauge? If not, you need one and know how and where to hook it up. You also need to know where the pressures should be. There is a cold and hot spec. All warm up regulators are different but the pressures run close to being the same.

How is your ignition system. By adding a turbo, you are really putting a big stress on the coil. I had a turbo Fiat X1/9 back in the day. One time, I could not get past 5psi boost. I tried everything. Once I threw on a new coil, I had plenty of boost. The fact was there was not enough energy for the spark to jump the plug gap with pressures above 5psi.

Again, I would stop with making adjustments willy nilly and start setting things up properly. Set the timing to stock and leave it there. Set the fuel pressures to stock and leave it there. Put everything to stock and then see what happens. Work in small steps, record what you are doing. It will take a lot of time and it will be agravating but it's what has to be done so you know what to do next.

There is no simple answer to your problem.

My 2 cents, your turbo is way to big for your car. You'll never build boost where you want it. Only at the top end.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top