Topic: Turbochargers

[Jeffy]

Since, this question keeps coming up in other threads lets put it all in here.

Questions like:

• Choosing a Turbo
• Mounting
• Engine Management
• Intercooling
• Bypass/Recirculation/Blow off Valves
• Timing
• Air/Fuel
• Any other Turbo related issues

PROJECTS

• Sean's Turbo Project
• Rob's Turbo Project

[tttppp54]

whats the easiest and/or the most cost effective way to control the fuel?

[Jeffy]

whats the easiest and/or the most cost effective way to control the fuel?

I'm no expert but I think that would depend on how much boot you're going to use.  For light boost, many mfgs. just use larger injectors or adj. fuel pressure regulators.  You can adjust the fuel level a little by getting an adjustable MAP.  Some people use a dedicated 5th injector and piggyback computer that compensates for the lean condition.  You could also bypass the whole OEM computer and run a custom one where you can remap everything and control timing, too.

[tttppp54]

so on say around 6-8 lbs of boost do u think larger injectors and an adjustable map sensor work?

[chrisfranklin]

I've owned & driven Turbo cars - domestic and foreign.  I have no self-control and the Turbo was boosting hard all the time. Gas mileage was shi-tacular. 

Wise man once said, "Power wants to be used." 

If I didn't have the cash for a V8 or diesel swap +tranny and install, I'd supercharge before I'd turbocharge a 2.5.   I know supercharging has a much longer track-record on Jeeps - meaning there's less chance that you'll end up beta-testing a company's supercharger, because kinks will have been worked out a while a go.  And I know I'd get mugged on gas mileage - turbo or super - either way

[oldjeep]

How about just swapping in the complete 2.4L from an SRT4 neon or caliber?

[Jeffy]

How about just swapping in the complete 2.4L from an SRT4 neon or caliber?

You should check out Turbo TJ's introduction thread he mentioned the problems.  There were enough issues that he jsut swapped the turbo onto his existing engine and even that wasn't straight forward.

http://4bangerjp.com/forums/index.php?topic=3092.msg23950

[Air Sierra]

Here is a can of worms that just opened 

If you have a 2.4L get a PT TUrbo exhuast and Turbo and I will sell you the bracket but it is a DIY mod as far as the 2.5L there is 505 performance or get a universal kit and make up a header and make it work!! 

[Jeffy]

Here is a can of worms that just opened 

If you have a 2.4L get a PT TUrbo exhuast and Turbo and I will sell you the bracket but it is a DIY mod as far as the 2.5L there is 505 performance or get a universal kit and make up a header and make it work!! 

As far as I know the 505 performance is a 4.0L kit though.  Will that be an issue?

"1991-1995 Turbo System
This system is for 1991-1995 Jeep with a 4.0L engine. The package includes a Garret Turbo, complete exhaust, Split second Electronic fuel management 2 bar map sensor, injectors (26-32lbs), all hoses and hardware, BOV, K&N Filter, boost guage. Must be fuel injected and no after market computer chips."

For $3450.00, I don't see them selling many.  Not to mention stuff like the exhaust will have to be tossed since the manifolds won't match and neither will the head pipe.  I know Avenger and Hesco are cheaper too.

From a DIY, I would suspect this could be done for much less.  To keep cost down, wouldn't it be easier to mount the turbo after the stock manifold so a custom one doesn't have to be built.  (any issue with that?)  This is the way some other people have done it.

[Air Sierra]

Here is a can of worms that just opened 

If you have a 2.4L get a PT TUrbo exhuast and Turbo and I will sell you the bracket but it is a DIY mod as far as the 2.5L there is 505 performance or get a universal kit and make up a header and make it work!! 

As far as I know the 505 performance is a 4.0L kit though.  Will that be an issue?  Do you know what they use for engine management?  I would think that it would be easier to mount the turbo after the stock manifold so a custom one doesn't have to be built.  (any issue with that?)  This is the way some other people have done it.

The problem with mounting it after your exhaust manifold is the turbo will mounted low in the engine bay not good for water crossing.

As far as engine management bigger injectors and a after market air/fuel insturment to know if you tuning is right. 505 performance might be able to make a header for the 2.5 since the 6 cylinder and 4 cylinder are kind of the same beast..

[Jeffy]

The problem with mounting it after your exhaust manifold is the turbo will mounted low in the engine bay not good for water crossing.

As far as engine management bigger injectors and a after market air/fuel insturment to know if you tuning is right. 505 performance might be able to make a header for the 2.5 since the 6 cylinder and 4 cylinder are kind of the same beast..

I took a closer look at 505's pictures under a microscope, they mount theirs on the passenger side of engine so they don't have to change out the manifold.  So the down pipe goes under the engine then back up on the passenger side but instead of going to the cat, it goes up to where the AC used to be.

There doesn't seem to be an intercooler used so it must boosting that much.



Found this picture, looks like theirs.

http://jeep.blogplot.com/13/img_Aug_19_2005_18_25?display=original

[Air Sierra]

The problem with mounting it after your exhaust manifold is the turbo will mounted low in the engine bay not good for water crossing.

As far as engine management bigger injectors and a after market air/fuel insturment to know if you tuning is right. 505 performance might be able to make a header for the 2.5 since the 6 cylinder and 4 cylinder are kind of the same beast..

I took a closer look at 505's pictures under a microscope, they mount theirs on the passenger side of engine so they don't have to change out the manifold.  So the down pipe goes under the engine then back up on the passenger side but instead of going to the cat, it goes up to where the AC used to be.

There doesn't seem to be an intercooler used so it must boosting that much.



Found this picture, looks like theirs.

http://jeep.blogplot.com/13/img_Aug_19_2005_18_25?display=original

My turbo is right were the AC compressor woould go I would like it higher but that is no possible when using the stock PT exhuast manifold......I would run a intercooler no matter how much boost I run a water to air so at low speed ( no air throu the radaitor area at low speed) there is good cooling for the air charge.

[Jeffy]

My turbo is right were the AC compressor woould go I would like it higher but that is no possible when using the stock PT exhuast manifold......I would run a intercooler no matter how much boost I run a water to air so at low speed ( no air throu the radaitor area at low speed) there is good cooling for the air charge.

Yeah, I think I'd run an intercooler too.  I noticed the biggest difference between your 2.4L and the 2.5L is that the exhaust manifold is already on the passenger side.  From what I understand, it's better to have the turbo sit as close to the manifold.  So would it be better to make a flange that bolts to between the manifold and the down pipe.  Perhaps an upturn then have it go down to get it up higher?  The only consideration is the intake manifold is on the same side as the exhaust so it would have to sit lower then the intake.  Heat might become an issue with them too close though.  Maybe I'll take some pictures of the 2.5L to put up in this thread.

The other issue with fuel, I was reading that adjusting the MAP isn't a good idea since it will only change the length of each squirt which could mean spraying when the valve closes.  So larger injectors and a vacuum controlled fuel regulator sound like a the right way without going to a piggyback system.  Then use some EM to watch over that.

[Air Sierra]

My last jeep had the 2.5L The intake is not a problem becuase the turbo intake face foward so you put a filter on the other side of the engine bay then it goes to the turbo, out of the turbo throu the intercooler then into the engine. So this is not a problem.

stock 2.4L:


Turbo mod in the pics it was not completey finished so some thing changed.

[wrangler387]

Your injectors fire with the valves closed all the time. It isn't a big deal. The issue with an adjustable MAP sensor is that it just jumps you up into the higher MAP bins (hense more fuel). but this means your jeep injects more fuel throughout the whole RPM bandwidth, and the stock bin probably only goes to 100kpa or so since it is N/A stock. This means there is no correction for more boost, your injectors only inject whatever the value is in that last bin reguardless. I'm running megasquirt for my fuel, i have my turbo mounted infront of the motor facing left/right instead of forward/backwards, since I was planning on putting a/c on my jeep. I dont think i will be completely my project since i think i'm going to be selling the jeep though.... I'll post some pictures of what i have accomplished so far later tonight, since i doubt i'll be making a thread now dedicated to my complete and running set-up.