Turbo project

I am planning on doing a turbo for my 4.6 in a couple of months. So far, the only turbos I have come across at the pull-and-save are for smaller engines with displacement under 2.5L. The goals of my project are to create a set up with minimal lag, be able to run 2-5lbs of boost, and fit completely under the hood. I would like to have the manifold come strait out with the turbo next to the intake manifold, it looks like there is enough room. I would like to begin building the manifold soon, is there any special considerations when building one, do the runners need to be equall lengths? I will be making it out of my old renix manifold. Is it a good idea to go with a smaller turbo? It will spool quickley and I don't think 5lbs of boost is past there limits? All my parts will be from the pull-and-save, turbos are $16 IC's are $16, blow off vales and wastegates are $8. With my 24# injectors, adjustable MAP, and relocated IAT, the RENIX system should be able to adapt to the boost conditions and I should be able to get a working turbo system for under $150. Any input would be appreciated.

It looks like you'll beat me to my turbo setup but heres the best place to find the information you need. These guys know how to put it all together. It can take some time to get all the info you need plus i belive there are some books out there aswell.
http://autos.groups.yahoo.com/group/jyturbo/?yguid=112887697

Make sure to take lots of photos! There are a few others who would like to do the same.

As for the Manifold, I have no idea. I would just try and make the tubes as smooth and kink free as possable. With a turbo, flow is your friend. More air going in needs to somehow get out.

With the mods that you described with the bigger injectors, map adjuster, and IAT relocation, 5lbs of boost sounds safe. If at all possable take it and have it dynod. When on the dyno you can stick a wideband O2 sensor in the exhaust and fine tune the map sensor to A: get more power, and B: keep from leaning out the motor and blowing it up.

Another thing to consider is making the CPS sensor adjustable. I cant remember how much timing adjustement the Renix system can do but timing and a turbo are critical, as I have seen a few turbo cars make 10-15hp gains from changing the timing a degree or two.

Also, an adjustable fuel pressure regulator might be a good idea to help with the fuel delivery under boost when you really need it. They make boost dependent regulators, but I havent seen one specifically for a Jeep. Its all about experimentation.

Good luck

AARON

Quick thought: Why not make it a twin setup since the turbos are small?

I am going to set up an air/fuel guage after I bolt my stroker in so that should get me close with the fuel delivery. With the renix system you can run a high altitude CPS that offers a few degrees advance, I believe Bill Vista was even able to find a way to retard timing with it. I will most likely be doing this. I thought about a twin turbo set up but I have doubts about space. If I can't find a suitable single turbo then I might have to think more about the twin turbo.

JY turbo group

They are a good group, but most are ford freaks, a couple of ricers, and 1-2 SBC. I tried to get them to help me get my turbo set up, but they were all conflicting each other, and other info I got else were. I have a A/R Gerrat T04B that came off a 7.0L cat diesle engine, some say it wont wind up until ~4-5K, and others tell me it will start at 3K and spool out at 4K. There has been the issue of diesle exhaust not the same as pump gas, that it flows differntley differently. Until last night, no one was able to tell me how it was different. Some buddys of mine are diesle machs and they told me that a diesle runs around 18:1 CR. It flows more air than a pump gas. So with a smaller motor and a lower CR, that should even out the set up for me. IMHO

:anon:

Lake- That T4 may work well, however can say until you find out what the compressor and turbine housing ratios ect. What trim is that thing running. The pure volume of a T4 used on a 7.0 is huge. Generally speaking without seeing any figures on it, Id say that the turbo wouldn't spool until high RPM...about 4-5k on a 4.0L. The volumetric efficiency is very different on the 7.0 diesel vs. the 4.0. Although I am not certain what the change would be on the CR issue..since a 4.0 doesn't get up to 18:1 even on a good day. Maybe you could call turbo city for some advice. SOME of those guys are helpful.

CW. said:

I am planning on doing a turbo for my 4.6 in a couple of months. So far, the only turbos I have come across at the pull-and-save are for smaller engines with displacement under 2.5L. The goals of my project are to create a set up with minimal lag, be able to run 2-5lbs of boost, and fit completely under the hood. I would like to have the manifold come strait out with the turbo next to the intake manifold, it looks like there is enough room. I would like to begin building the manifold soon, is there any special considerations when building one, do the runners need to be equall lengths? I will be making it out of my old renix manifold. Is it a good idea to go with a smaller turbo? It will spool quickley and I don't think 5lbs of boost is past there limits? All my parts will be from the pull-and-save, turbos are $16 IC's are $16, blow off vales and wastegates are $8. With my 24# injectors, adjustable MAP, and relocated IAT, the RENIX system should be able to adapt to the boost conditions and I should be able to get a working turbo system for under $150. Any input would be appreciated.

Click to expand...

Are you planning to draw through the TB? If so, move the MAP and IAT upstream of the turbo. The MAP only reads vacuum, the IAT should read what enters the turbo from the same location as the MAP vacuum.

I would reuse as much of the factory intake as possible for the initial configuration. This allows you to focus on tube routing for the TB to turbo, and turbo to intercooler and then manifold (rather than building something more complex to begin with). If the initial turbo proves too small (cannot provide WOT boost at highway rpm) then a simple system is easier to upgrade.

The theory to keep the compessed volume minimal is true, but impractical when blowing through a large intercooler (essentially blowing through a radiator). The benefit of an intercooler is greater than an idealized flow path and volume.

Buy and study the turbo books for the effective airflow vs. rpm & compression ratio calculations with the size turbo you can find (to predict what will happen with the cheap parts). You will spend considerable time tuning, so make everything else simple.

Buy everything the P&S has available, including the air to air intercooler.

Good luck, and keep us posted.

Thanks for the tips. I agree on keeping it simple, this is the type of project that could get overly complicated and expensive in a hurry. I all ready have the IAT in the air tube and I was wondering about how the MAP would react to posotive manifold preasure rather than vacume. This weekend I will hit the junkyard and pick up everything I might need.

Ed A. Stevens,

Wouldnt a water to air intercooler be easier to set up than an air to air unit? The reason I ask is where the hell are you going to mount an air to air intercooler and piping on an XJ with out it being in dangers way such as being smacked by a rock?

Then on the flip side, how would you set up a water to air unit? I see the mounting of a mini radiator and running water hose easier than tubing supporting an air to air unit.

Thanks,

AARON

I think a water injection system may be easier than an IC, especially for lifted off-roaders like me. I have always had a concern with injecting water into my engine though.
I did a search for homebrew water injection and found some usefull information.:
http://www.lehigh.edu/~erp4/saab/Upgrades/WaterInj.html
http://website.lineone.net/~da.cushman/misc/mannject.html
http://home.att.net/~stevemon/AlcoholInjMod.html
I also was thinking about running a 7nth injector off of the #1 wires and running the lines to a water tank.

WI Chemical Reaction

It can be a little confusing, but I get the idea.

:repair:

I was thinking of putting in injectors and running a t off the rail, or do an extra fuel manigement to control water injectors. Using the megasquirt.

MrShoeBoy said:

Ed A. Stevens,

Wouldnt a water to air intercooler be easier to set up than an air to air unit? The reason I ask is where the hell are you going to mount an air to air intercooler and piping on an XJ with out it being in dangers way such as being smacked by a rock?

Then on the flip side, how would you set up a water to air unit? I see the mounting of a mini radiator and running water hose easier than tubing supporting an air to air unit.

Thanks,

AARON

Click to expand...

I would think you would need to find a water to air intercooler, first, before deciding what is easier to install?

The XJ is a challenge to find room for any intercooler. Maybe the first attempt should be without an intercooler?

Another common intercooler method is to use an A/C evaporator as a refrigerated intercooler (run the A/C compressor to cool the intake air). With the limited room in an XJ, this may be the best solution (and one than can be turned on and off).

I would not expect a turbo to be the ideal supercharger for an off-road XJ. The concern is heat, excessive heat with the turbo, in addition to the XJ cooling issues. The turbo may be more efficient supercharger (great on the street), but the heat generated and contained in the exhaust may present a larger problem off-road where low speed cooling is already limited in the XJ.

OK I think I have an IC solution figured out. I am going to build a circuit that triggers a fuel injector everytime the #1 spark fires. I will work basically like a timing light. I will inject the water/alch. mix into the airtube. The injector should atomise the water well enough to not damage the turbo, and there is no risk of hydrolocking the engine from an accidental siphon.

Ed A. Stevens,

The A/C idea is totally off the wall! I never thought about that. I am going to look into that. Sounds really sweet if it where set up correctly.

As for the heat, I dont see why a good water pump like a Flowkooler, 180 t-stat, and a good aftermarket radiator such as a modine should have any problems handling the heat so long as everything was in correct working order. As long as an eye is kept on the temp gauges and nothing is getting excessivly hot, there shouldnt be a problem.

CW,
That sound like a good idea but what type of injector where you looking at? There are mister tips that are specificaly for turbo setups and they cant be that cheep. Would TDC on #1 be enough spray or too much?

AARON

BTW: This is a great thread so far Lets keep the info coming!

I was planning on prototyping the water injection system with one of my stock injectors and a canibalized section of my stock fuel rail (everything was upgraded for my stroker) I will install a thermometer in the intake and play with the setup until I have the coolest temp I can get out of it.

propane

I wish i could find where I had read it but propane injection can take care of 2 things at once. first off its a very high octane fuel to help prevent leaning out and the second is that when released in its gas form it is kinda an inercooler in a bottle. therer are some small innercoolers from ricers both air to air and water to air that would work in the tigh confines of the XJ.

I went to the junkyard yesterday and got all the parts I need to finish my stroker. I passed up a turbo that was in a Le Baran Turbo because it was so small, there are several of those in the yard and it seems like they get robbed really fast. Should I go for the turbo or keep looking for something bigger? I guess I could just use it to prototype with and then upgrade if I think I need to. I got all the materials for my injection system and I will post a writeup when I complete the project, along with the turbo manifold construction. I may do the injection just so I can use regular gas on my stroker (it basically raises the octane level) and work the bugs out of the system before I install the turbo. I am planning on running an alcohol/water mix so the extra fuel in the mix should help when I'm in boost.

From turboing my 6.2 Chev diesel, here's what I learned. BTW, I built the manifold myself and socred a used RayJay sized for the application.

You MUST have a near-vertical return line for the oil return. Uphill or near horizontal are absolute NO-NOs. Use 3/4" ID hose or larger since it will be coming out foamed in some applications.

Make sure you have enough room around the turbine housing for heat issues.

Intercoolers are nice, so consider where to put one if you don't do it now. The higher the PSI, the more interesting an intercooler becomes. Air-air is fine.

Be sure to size your turbo appropriately. Get one off something in the similar 4-4.6L range.

Consider a wastegate, either attached or upstream. This can save your motor.

Recently there was an article in one of the Honda mags where they turbo'd an FI CRX. Looked pretty simple overall. Routing the tubing was the hard part.

Let us know how it comes out!

The more I think about it I don't see any practical way of mounting the turbo next to the intake manifold. I was looking at a diagram of the deisil xj's turbo and it sits below the engine, pretty much where the manifold ends on the 4.0. I think it would be much easier to bolt the turbo up down there and then just run the intake line up. I would make a skid for it, and the UCA isn't a concern for me because of my long arms.

P.S. I have the water injection circiut finished, I just have to get my stroker runnin so I can test it. If everything works out I will post a writeup.