Re: 89 CSX 10 rides again!
If the car is still VNT, the free flowing exhaust will most likely overboost no matter what you do. They corked the exhaust to control the boost, as the 2.2 is too large for the tiny VNT turbo. Do you still have the stock air box on there with a regular filter? That will help some. I have CSX VNT #497 with a S60 VNT turbo on it and the car can fairly well control the boost with larger exhaust, but I've tried to choke it off as much as possible, and to be honest, I never wind it out because I know that it will just overboost. When I need to do some exhaust work, I'll put a more restrictive exhaust on the car.
I wouldn't think of doing a zener diode on the car. With the guys on the site offering flash modules for SBECs, and the tuning capabilities that come along with that and tools like the MPSciLink, I wouldn't dream of going back to the dark ages. Aside from that, I also wouldn't do it because you'll overspin a VNT in short order at higher boost levels. If you've ever had one apart, you can see that the wheels are tiny and the RPM necessary to generate more than stock boost levels is insane.
If you want to mess with the VNT a little, there is some good information from 5digits on TDG from back when. Testing for minimum attainable boost is included in there if I'm not mistaken.
http://www.thedodgegarage.com/turbo_vnt.html
thedodgegarage.com/5digits_turbos.html
https://www.youtube.com/watch?v=mQV3k5Ncl-8
Re: 89 CSX 10 rides again!
If you trick the map you'll probably get melted pistons the vnt will just put in tons of boost and lean it out
Re: 89 CSX 10 rides again!
It still has the original VNT. Couldn’t you just use a boost controller with the diode?
Re: 89 CSX 10 rides again!
Quote:
Originally Posted by
89csx10
It still has the original VNT. Couldn’t you just use a boost controller with the diode?
You're overboosting because the VNT can't control the boost. As you make more boost and more power, it will just runaway more and more. You're essentially trying to trick the map to allow the turbo to make all the boost it possibly can. That will probably cause detonation due to the insane heat the VNT will be putting out. It will also spin the VNT to death in short order. I attempted to find a compressor map for it, and the one crude map seemed to indicate that at "all of it" boost levels, you'll be further off the map than Columbus was.
What are your goals for the car? If you want a fun driver with instant boost and the street cred of it still being VNT, you'll need to cork the exhaust. If you want something significantly faster than stock, you'll need a different turbo. To hopefully put it in perspective, 5digits used to say that if you want to work on the exhaust of the VNT, just use a TBI muffler because they are higher flowing, but you won't overboost.
Re: 89 CSX 10 rides again!
Quote:
Originally Posted by
cordes
TBI muffler because they are higher flowing, but you won't overboost.
Did you mean higher backpressure?
Re: 89 CSX 10 rides again!
Well, it’s a learning experience for sure. Just a fairly stock driver was all I was going for, with mods being the exhaust and a stage 2 tune from Cindy. Maybe should have done some better research. I’m not driving the car as a daily or anything. It’s completely stock and I’ve owned it for about 12 years now. Just wanted to liven it up a tad. I won’t be redoing the exhaust, with putting the money into having it done and ordering it from FWD. I imagine the new computer will adjust for this to a certain extent and I certainly don’t want to kill a good car. Thanks for your replies guys.
Re: 89 CSX 10 rides again!
Quote:
Originally Posted by
chromguy
Did you mean higher backpressure?
If I recall correctly, the TBI muffler was higher flowing than the stock unit, but would still allow for the computer to control the boost.
Re: 89 CSX 10 rides again!
Quote:
Originally Posted by
cordes
If I recall correctly, the TBI muffler was higher flowing than the stock unit, but would still allow for the computer to control the boost.
Ah OK thanks
