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468Chevelle
01-17-2007, 10:37 PM
I just purchased a 1989 Chrysler Lebaron convertable with a 2.5l turbo. Its in very nice shape. 121k miles (odometer broken), automatic. I get in it and flog on it. It has a factory boost gauge which shoots to 15 psi and the vehicle just rips. It has a mits. TE04H turbo. I put a scanner on it and it has a target boost of 18 psi. I thought these were suppose to boost to 7 or 10 psi. I checked the gauge. It is correct. I even have been able to mark where 20 and 25 psi are on the gauge. My plan is to put a used 3.3l throttle body on it, install the zener diode, and buy Alky Control methanol injection and slowly turn up the boost. I'm looking of 13 second runs. What do you think are the chances? Any other cheap and simple mods to help my cause? Anybody tried this on a Lebaron? Thanks for any input

slasky
01-17-2007, 10:39 PM
Don't waste your time with changing the throttle body.

Whorse
01-18-2007, 02:10 AM
I have a 90 lebaron, and these suckers are HEAVY. The 89 CSX was over a second faster in the quarter mile with the same engine, just different transmission and less weight.

Darkwolf
01-18-2007, 02:24 AM
Shouldn't go over 9psi from the factory and you should be hitting cutout at 14.7 so either the gauge is flaky and most of the factory ones are or somebody has messed with it. They mitsu might make your goals a bit hard to reach. They suck or is it blow ;)

468Chevelle
01-18-2007, 11:33 PM
I'll take it to the track for a baseline and post the results. The boost gauge shows 15 psi before it pops from the overboost. I'll get a zener diode in it. To be safe, I'll put a 100 octane in and run it. I forget, is it a 4.5 volt or 4.7 volt diode?

TurboGLH
01-19-2007, 12:17 AM
4.5v stock or 4.7v on a mopar performance computer.

1FastCSX289
01-20-2007, 12:30 PM
Yea, it might be tough with that mitsu turbo......and how are you planning to add fuel beyone the 14.7 cut out? Just the alky?

Really, your best bet would be to dump the mitsu, even if its just for a stock garret. Put a MP head gasket on it at the same time. Get a custom cal, 3 bar MAP, +40 injectors, and if youre stuck on alky, use it for the intercooling effect. Oh, and dont forget a larger exhaust. And as Slasky said, dont worry about the larger T.B. unless youre going with a ported head and intake.

This route will obviously be more expensive (maybe 5-600 bucks), but it will give you much better, more reliable results.

Snailpower
01-21-2007, 10:44 PM
Following this thread closely, since I just bought the same car. Mine goes into overboost right now, so I am still sorting out the problems. I sure don't want mine to run in the 13's, but would be real happy with a high 14/low 15.

Oh yeah, what the heck is a zener diode and what does it do/where does it go???

cordes
01-21-2007, 11:40 PM
Oh yeah, what the heck is a zener diode and what does it do/where does it go???

The zener diode allows the computer to only see so many volts so you can run more boost (over 14.7) and eliminate the overboost cutout. They are also refered to as map clamps in some circles.

Whorse
01-21-2007, 11:45 PM
To elaborate on the zener diode question, zener was the guy who invented it, hence the name. It's a diode that is placed across an electrical circuit, and limits the amount of voltage that goes past it down the circuit. For example, if you are getting 14.7psi at 4.5V, and you want to run more boost, get a zener diode that is as close to 4.5V without going over and the computer will always think it's only boosting to 14.7psi.

Darkwolf
01-22-2007, 02:04 AM
You can also use a cutout raiser instead of a zener
http://www.xmission.com/~dempsey/perform/injector.htm
Thats what I run on my van.

468Chevelle
01-26-2007, 10:57 PM
I was reading up on Alky control system. Basically the idea is to watch your o2 and knock, and slowly back down the fuel and add more methanol. You get the cooling effect of alky and raised octane rating to prevent the knock. The only way I can think of is to change the zener each time to a lower voltage and raise the gain on the alky control. 1/4 mile after 1/4 mile test should show the improvement. I know the mitsu sucks (or blows), I just want to see how far you can get on the stock stuff before it time to improve. Probably just wishful thinking for anything near 13's, but interesting to see if the 14's is possible. What do you think?