boosting the 4.0?

[Desertjr]

What would be the preferred engine management system? I believe Bryson(boostwerks) runs the aem fi/c? Others I've seen on megasquirt... Whats the price range on them? This would be going into a 1988, 5 speed, 4.0, 4wd. 4.2L mini stroker, ported 7120 cast(1.95/1.54 valves), 99-04 cam advanced 4*. Compression can be lowered some by dishing pistons.
I think the 2229 pistons would be the best "off the shelf piston" because its so thick..able to run a 30cc dish. So its got alot of material there to take a beating from heat or minor counts of knock. Budget in mind here. What else would you do to a boosted motor internally, besides forged pistons & tuning & injectors or cooling intake charge ect ect? That's all given stuff, but what little things, like clearances, gaping piston rings, stuff along those lines?
I've seen as much as 5-7psi with just a map adjuster & wideband. Others claim you'd need a way to control timing for knock, while some builds don't and run just fine without issue daily driving. Being a renix I have a working knock sensor, I also have egt & wideband & a map adjuster for tuning. It won't read positive pressure? or boost, so its only good for playing with fuel trims. I already know that but would anything more really be needed at such a low boost level? Again others have run the same amount or slightly more with a way of adjusting timing.
TurboTPI on jeepforum for example, turbo'd his grand. I believe at 8-10 psi with no changes to the timing map from what I have found. Just upgraded the fuel system and tuned it from there via wideband & map adjustments. I could manually retard my timing 1-2* or more via the CPS sensor. Others advance it up to 6* by simply shifting its position..1 could simply shift it the opposite way to retard timing as well.

I know turbo anything costs a bit of money, its not cheap, nor is it for beginners. I'm not a beginner but I do have a budget in mind! I'm asking honest questions because I want honest answers. Its been posted & asked previously on this forum and many others, but most of whats posted is, "oh you'll blow it to the moon", or "you NEED this or it won't work". Which is obviously false! Do I NEED a way of control timing at such a low boost level, or would it just be favorable? Obviously its favorable but seems unneeded if others in the past have gotten away without it? I'm too far into my 4.2L to back out and go 4.7L..so why not turbo the 4.2L came to mind, hence this thread!

[CobraMarty]

At 5-6 pounds boost, proper fueling and some sort of intercooling you could probably get away with no timing retard. Basically you need 1* retard for each pound boost. Since the stock 4.0 can tolerate 6* of advance with the CPS mod, by leaving it in the stock position you are already sort of have retard built in.

[Desertjr]

My build plan wouldn't change much other than pistons & piston dish. Using the 2229's would give .002 above deck. Using a .043 head gasket = .041 quench. Chambers 61cc. 99-04 OEM cam.
Now compression can go a few different ways. 19cc piston dish & install the cam 4* advanced giving more low end torque/power on the motor alone from the cam advance. IVCA = 49.95. This gives 8.8 static & 7.75:1 dynamic. Or install the cam straight up 0* and a 15-17cc piston dish which gives, 9.16:1 - 9.0:1 static & 7.87:1 - 7.71:1 dynamic pending the dish used. And would give a 53.95 IVCA.

Personally advancing the cam would give more power over all & gives less overlap which is good for boosted applications? And I think would be the stronger motor over all! And the compression numbers aren't that far apart and at that low of compression, should easily handle 5-7psi.

[Desertjr]

At 5-6 pounds boost, proper fueling and some sort of intercooling you could probably get away with no timing retard. Basically you need 1* retard for each pound boost. Since the stock 4.0 can tolerate 6* of advance with the CPS mod, by leaving it in the stock position you are already sort of have retard built in.

And I always thought the same. I think I'm over thinking the whole, "need a EMU to retard or play with timing". If anything I could always do the opposite of the n/a guys and reverse the cps to retard timing a few degrees. However I'll let you look at the compression numbers I just posted and see what you think lol. Its not a stock 4.0 I'd be doing it to. It'd have a much tighter quench, ported head, bigger valves, but ultimately more compression....

And intercooler no, meth injection yes. No space for a intercooler ANYWHERE. dual batteries, hidden winch setup, OBA compressor & keeping the a/c...I won't have the room. I had already planned a small, very small, .5GPH injection for my motor even if it was n/a..only for really hot days, but also to help "steam" clean the motor every now and again of carbon or oil deposits. Point being I have a meth injection kit on hand, would just need a properly sized nozzle for the boost levels being run.

EDIT: to add this is probably the 5th or 6th logged thread of a turbo inline 6. Stock timing curves, just playing with fuel. However only very few are sticking around and updating on reliability & such. But the basic seems don't push it too far, to much boost, not enough fuel ect ect, which again is obvious stuff!
http://www.jeepforum.com/forum/f12/few- ... ndex4.html
This guys numbers are great! 200hp & 260ftlbs at the wheels! My 4.2L stroker is only estimated at 310ftlbs at the crank lol. Add in 5-7psi & possibly retard the timing 2* or so, and I should be plenty safe..of course it'd all be in the tune when its dynoed. Until that point I'd never know. Anyway that would put me close to 300ftlbs I'd guess? Between the compression bump, head work, tighter quench... And to boot my estimated torque curve now is 310ftlbs from 2000-3600rpm or so according to desktop dyno. Thats with advancing the 99-04 cam 4*, installing straight up nets me 275-280ftlbs.

[SilverXJ]

Montelibre ran a supercharger on his stroker with no fuel modifications other than larger injectors. It failed and holed piston. http://www.jeepstrokers.com/forum/viewt ... f=5&t=2474

Then there is this guy, which kind of disappeared. http://www.jeepstrokers.com/forum/viewt ... f=5&t=2477 He was just planning on running the stock map w/o a piggy back. But I think he got an FTC1... and I has hoping it would get interesting. I don't know how its running though.

You are also using cast pistons, which won't be forgiving to a lot of knock. They may take more than a hyper. I know you are concerned about cost, but you may want to think of a forged piston from Bulltear. You can spec the dish size, but their pistons are designed to work with the 4.2L crank and 4.0L rods. They may be able to do something for your mini.

Modifying the CPS will retard timing across the whole band, not just where you need it. Putting the IAT in a warmer spot will also retard timing

You could do the wait and see experiment since you have a wide band. However, I don't think the PCM will be happy with injectors large enough to run the turbo & stroker w/o some kind of piggy back. Cold start up will be nasty with a surging idle. At one point I had 27 lb injectors on my stroker, which were way too large. For the first two minutes of start up the idle would go up and down and the exhaust would be very rich. The PCM just couldn't tune enough fuel out at that point to be happy. I would recommend an AEM FIC6 (one for a Neon) if you want a piggy back. The FIC 8 is also an option as it has some more features over the FIC 6, but it costs more.

[Desertjr]

Montelibre ran a supercharger on his stroker with no fuel modifications other than larger injectors. It failed and holed piston. http://www.jeepstrokers.com/forum/viewt ... f=5&t=2474

Hmm...same motor? Piston damage looks 100% identical. You can see small circles located around the hole in the pistons in the thread and in these pictures? I ask because I was going the I out that motor for parts and was curious what all it had done?
http://www.naxja.org/forum/showthread.php?t=1097521

[CobraMarty]

Running the stock cam advanced 4* and decrease overlap is good. Straight up would also work. Run 1.7 roller rockers to get a little bit more lift out of the stock cam. Only use forged pistons. Don't retard the CPS across the whole range, only retard under boost. You want as much advance as possible without detonation when N/A to get crisp throttle response, power, and mileage.

I would consider doing this build in 2 steps. Build the stroker, install it, break it in, Get the stock ecu tuned, get it running properly. Then install the super/turbocharger and address the need for added fuel and timing retard then.

A couple of things will happen.
1-something will break in the stroker during 'break in period' first 1000 miles and not due to boost
2-it will run great, tuned well and be very satisfied and stop here
3-add the forced induction and not get it tuned right, run lean or too advanced timing and break or 'hole' something
4-add the FI and everything tunes well and you live happily ever after

There are many examples of those that tried to short cut the process and where are they? broken and frustrated.
Do it right, Do it once. That works for me.

[SilverXJ]

Running the stock cam advanced 4* and decrease overlap is good.

Advanceing the cam will increase the DCR a bit. You can't change the overlap by advancing or retarding the cam. It must be reground.

Get the stock ecu tuned, get it running properly.

I believe he has a 1990, not tuning.

Montelibre ran a supercharger on his stroker with no fuel modifications other than larger injectors. It failed and holed piston. http://www.jeepstrokers.com/forum/viewt ... f=5&t=2474

Hmm...same motor? Piston damage looks 100% identical.

Different engines. Montelibre is in Spain, the other in California.

[Desertjr]

Running the stock cam advanced 4* and decrease overlap is good. Straight up would also work. Run 1.7 roller rockers to get a little bit more lift out of the stock cam. Only use forged pistons. Don't retard the CPS across the whole range, only retard under boost. You want as much advance as possible without detonation when N/A to get crisp throttle response, power, and mileage.

I would consider doing this build in 2 steps. Build the stroker, install it, break it in, Get the stock ecu tuned, get it running properly. Then install the super/turbocharger and address the need for added fuel and timing retard then.

A couple of things will happen.
1-something will break in the stroker during 'break in period' first 1000 miles and not due to boost
2-it will run great, tuned well and be very satisfied and stop here
3-add the forced induction and not get it tuned right, run lean or too advanced timing and break or 'hole' something
4-add the FI and everything tunes well and you live happily ever after

There are many examples of those that tried to short cut the process and where are they? broken and frustrated.
Do it right, Do it once. That works for me.

2 step process sounds the best I think. And ya tuning for me would mean a full stand alone. So I've gotta map adjuster..but I should be ok with my low expectations if its running at the right afr. Now to decide if I should low the dynamic and static from my n/a step, to a "possibly" boost setup?
It would be 9.5 static & 8.4 dynamic & .039 quench roughly after todays calculations. Boost would be 9.1 static & 8.0 dynamic and quench would be .040. I could lower this a bit by dishing the pistons a bit further. I could go safely down to 8.5 static & 7.5 dynamic.
Pistons would be the 2229s which are cast not hyperuwatchacallems. I think BullTear are 500 a set and like 4 month wait time right? Any other options for forged? If I could get a 30cc dish I can get down to 8.3 static & 7.3 dynamic and could go lower with a deeper dish of course for lower.

[Desertjr]

I was all curious couldn't I order a set of forged pistons from 505? I know they are a hassle and such but their pistons aren't made by them so I should be alright! They give you the option of 8.5:1-13.5:1...I would of course find out the pin height and piston dish to get the correct compression in my motor.

[CobraMarty]

2 step process sounds the best I think. And ya tuning for me would mean a full stand alone. So I've gotta map adjuster..but I should be ok with my low expectations if its running at the right afr. Now to decide if I should low the dynamic and static from my n/a step, to a "possibly" boost setup?
It would be 9.5 static & 8.4 dynamic & .039 quench roughly after todays calculations. Boost would be 9.1 static & 8.0 dynamic and quench would be .040. I could lower this a bit by dishing the pistons a bit further. I could go safely down to 8.5 static & 7.5 dynamic.

What year is your XJ? Renix? Full stand alone- bag that, too much $, What displacement do you plan? 9.1 static and 8.0 dynamic would be fine with your low boost build.

[Desertjr]

2 step process sounds the best I think. And ya tuning for me would mean a full stand alone. So I've gotta map adjuster..but I should be ok with my low expectations if its running at the right afr. Now to decide if I should low the dynamic and static from my n/a step, to a "possibly" boost setup?
It would be 9.5 static & 8.4 dynamic & .039 quench roughly after todays calculations. Boost would be 9.1 static & 8.0 dynamic and quench would be .040. I could lower this a bit by dishing the pistons a bit further. I could go safely down to 8.5 static & 7.5 dynamic.

What year is your XJ? Renix? Full stand alone- bag that, too much $, What displacement do you plan? 9.1 static and 8.0 dynamic would be fine with your low boost build.

4,2l stock 99 cam. Renix era.
And actually adding my elevation..around 2000ft drops my compression to 8.7/7.6 for the boosted setup(dished pistons) or 9.1/8.0 n/a setup.