tsmysak1

Well, thought I would post my turbo experience for the general edification of the board. Somebody will read this some day and gain something.

I bought the car and it was almost completely stock with the exception that someone had put a downpipe on the car, thus removing the precat. It really ran hard, but there are some warnings about such things floating around, and so I went and bought a boost/vacuum gage to investigate. First blast up the highway yielded a 12+ psi on both the primary and secondary. The car has a stock intercooler. Conclusion : This is bad. A case of detonation waiting to happen. SEDs is a terrible disease (Severe Engine Damage Situation).

I read up on this to discover the two hose pills that control the boost level and prespool on the secondary. This was actually quite fun to learn about since this is a project for me. I have plans to keep the car as close to original as common sense allows. There are some things that need to be corrected of course.

I engineered a pair of valves to substitute for the pills. This is where the real fun begins.

The restriction in the short lines will be different from the restriction in longer lines, if you mount the valves in an accessible place. So this means you start from scratch trying to adjust these. I recommend mostly open. Since installing them I have managed to demonstate every conceivable boost pattern possible. 8-6-10, 8-12-10, 8-10-10, 10-6-10, 12-8-12, 10-8-11....and so on. When you have the primary lower than the secondary, it might not only be the control setting, but it also can be the control rod length on the prespool. Be forewarned that the adustment thread on the rod is often rusted due to the thermal cycling and is likely to break if you jack with it. Plan ahead.

Anyway, I had this 8-6-10 thing going on for a while. Safe but a bit pansy on the bottom side. There is a big difference between 8 and 10 psi. I took the valves off and blew through them to get a sense of how much restriction the system was seeing. The valves change restriction in a non-linear fashion, unless you get some high dollar stuff. You will be working with that last little bit of travel before they are all the way closed. I suggest getting small valves that match the size of the hose, or something that has a fine adjustment to it.

So after putting the airhandling back togther again (no small feat for a farm boy) I ran the car, 12-10-12. I set the prespool almost closed. This made me nervous, so I left the prespool tight and backed off the boost. 10-6-7 - Figure this one out. ??? I opened the prespool slightly and backed off the boost even more. I am back at like 11-8-10. It appears to me that the the prespool is really tricky. It is diverting primary boost to prespool the secondary, so the two controls are not really seperable. You increase the boost, you also increase the prespool to a point. If you increase the prespool, you lose boost on the primary. Argh! None of this explains how it is possible to get 10-6-7, but I do know the prespool was almost cranked closed. This should result in spiking, but I only witnessed that on one trial.

Well, I am not sure how helpful this info is, but I am convinced that you can use this method to get a good solid 10-8-10 pattern. I am not convinced that you can get to the ideal 10-10-10, although it should be possible. Today it boosted through the transition really flat, ...no lag....however, I do not expect this setup to work this way every time. The air was cool and moist.

Obviously the next step is a better system.