Topic: Turbochargers

[sharpxmen]

The Mopar 2.5L turbo engine had a lowered compression ratio of 8.0:1 for durability purposes.  By comparison, the 2.5L AMC-derived engine as used in the TJ had a 9.2:1 compression ratio.  Needless to say, running high boost levels with a high(er) compression ratio is a very delicate balancing act; I certainly wouldn't recommend it for any "casual" wrenchers unless you don't mind rebuilding an engine after you've blown it up.

The old school FWD turbo Mopar engines have horrible cylinder head flow.  For example, the non-turbo TBI version of that 2.5L engine only made 100 HP peak at the crankshaft.  (Even the TJ 2.5L--itself no gift to head flow--manages 120 HP.)  To make serious power on the turbo Mopars, we have to run serious boost; 14-18 psi is pretty common and typically easy to do on pump gas (even for me where I'm limited to 91 octane here in Utah).

There are a number of guys around the country running 28-35 psi on their Mopar 2.5L engines, though I personally never went higher than 24 psi.  I usually could only run about 18 or 19 psi max on 91 octane; I would have to mix in some 100 octane in order to go higher (which is why I had a dash-mounted HI/LOW boost switch, with LOW set to 18 psi).

At one time I ran an old cylinder head which had been planed a couple times.  Fearing a higher compression ratio, I used a copper head shim to replace some of the lost chamber volume.  While this worked okay, lowering your static ratio will soften your off-boost power and response; I wouldn't really suggest doing this unless it was absolutely required due to head milling or you were dead-set on running very high boost pressure.

Anyway, I hope that helps answer your questions.  I don't pretend to know every last little thing about turbocharging, but I do have lots of experience and have done years of research about it.  I'll be happy to field any questions brought up here, and I'll let you know if any particular topic is outside my area of knowledge.

i was thinking of doing something similar to what the i6 stroker guys are doing - mill some off the top of the piston but leave the quench area intact - not sure how much you can safely take off though, i was hoping you have some insight into that. I'm currently working on a spare cyl head i have to get it equipped with 2.02 intake valves and roller rockers but there's no room to increase the chamber volume there (or at least i don't think there is) without altering the shape so i was looking for alternatives.

[jackel]

Old thread dug up I know.  I'd like to clarify some things to piece together a good set up.  First off, thanks for taking the time and effort to R&D a setup for the 2.5.  I have recently traded into a 2000 Jeep 2.5, After market header, Manual trans, 4" Susp Lift and 33" tires.  The 4 banger isn't that bad around town but falls on its face in a big way when it comes to the highway.

I have read that engine swaps to the 4.0 I6, 4.3 Chevy or 350 Chevy aren't worth the trouble as the frame varies slightly from the 2.5 to the 4.0 that it simply makes fitting other motors in a complete hassle.  Aside from the fact I don't want to have to deal with adapters and such to make it work.

Plans:
Pull the motor and do a fresh complete rebuild on it, bearings, pistons, hone, etc etc.  

My goal:  
#1
Turbo 8psi boost setup, Pull roughly an additional 50-75 HP and/or 50-75 pounds torque.  (I'm not looking for a monster, but I am looking for something with a bit more pep to handle the lift and tires and not be constantly shifting to 4 on the highway, mashing the pedal and nothing happening.

#2
This is OBDII and I have emissions to comply with.  I can do an emission waiver but am limited on allowed miles driven.  I'd like to stay compliant with no check engine lights and crap.

The SET-UP (as I can remember through the reading)


-TD-05 12B Turbo (from a 1989 Volvo, (that is set for 8 PSI max stock)(Internal waste gate)
-Blowoff Valve
-30pound injectors
-Split Second - PSC1-002
-**Fabricate the turbo mount near the A/C compressor**
-**Fabricate the exhaust routing from the stock manifold to the passenger side and forward up to the turbo**
-**Fabricate the exhaust routing from the turbo back to the stock exhaust components**
-**Fabricate the intake charge pipe to the throttle body with the blowoff valve**
-**Plumb in the turbo to the cooling system**
-**Plumb in the oil feed to the turbo from the lowest spot of the oil pan**
-**Plumb in the oil return line from the turbo to the "above oil volume level" portion of the oil pan**

The questions I have?  I may have missed it if mentioned already

On the 2.5 for the 2000 TJ:

-Will I need a different, higher volume/pressure fuel pump or will stock support 8psi on 30# injectors?

-Will (Split Second - PSC1-002) work for OBDII compliant vehicles or  OBDI such as your's for example?

-Will I need an adjustable fuel pressure regulator?

-Is it necessary to tune using a Wide-O2?


Thanks a ton for the info.  

[sharpxmen]

The questions I have?  I may have missed it if mentioned already

On the 2.5 for the 2000 TJ:

-Will I need a different, higher volume/pressure fuel pump or will stock support 8psi on 30# injectors?

you're fine but if your calculations yield 30# injectors you will actually have 49-8=41psi (you don't have a vac/pressure port on the fuel pressure regulator, the fuel will have to overcome the boost in the intake so that is differential pressure) so calculate your injector flow based on that pressure at max boost (so would be more than 30lb/hr at 43.5psi as a result)

-Will (Split Second - PSC1-002) work for OBDII compliant vehicles or  OBDI such as your's for example?

not sure about OBDII - there was a guy here that tried to get it working on his TJ and ran into trouble, I have no idea why but could be related - look into AEM FI/C as it is listed as OBDII compatible (i think you can even get adapter connectors and not have to cut your harness) and from what i remember it also has an O2 signal modifier built in (so it will adjust the AFR in closed loop as well)

-Will I need an adjustable fuel pressure regulator?

not necessarily but it comes in handy

-Is it necessary to tune using a Wide-O2?

yes, it will make your life a lot easier

[sharpxmen]

-**Plumb in the oil feed to the turbo from the lowest spot of the oil pan**

Negative - you need to plumb the oil feed for the turbo on the pressure rail, common place is to split off with a T-fitting from the Oil Pressure Sender. the way you're thinking is not going to work, oil will not travel upwards from the pan to the turbo and will not flow no matter where you install the fittings and even if the turbo would be lower than the oil pan.

EDIT: unless you plan to have an external oil pump to feed the turbo (like an electrical one for example).

[GPSAR TJ]

those turbo dodges were incredible, had a bunch of glh omnis that I played with upgrading the comps, turbos , intercooling ect.. something about pullin away at the light in a 4 door shoebox that could move waay faster than it should was appealing. those minivans were incredible fast and saw some run in person, neat stuff. as for swappin a front drive 2.2/2.5 into a yj/tj, sounds interesting but man it was getting hard to find parts in the jy back then and most of them are scrap now so  dirt cheap parts would be an issue..

[sbsg2005]

i am currenly working on a turbo dodge swap slowly but i have had no trouble finding cheap parts other than forged pistons and those are never cheap the only other issue is finding the bellhouseing for the transmission cheap but a new one can still be had for around 200 bucks i got mine for 20 off of ebay.

[Vodkaman]

Keep us informed. I still have in mind to make such a swap to my TJ, though not any success story yet.

[turboTJ]

Hey everyone,

I was searching the net for help on my FTC1 tune and found the site. I am a long time jeeper and currently have a 97 TJ 2.5L AX5. I am running a 5lbs tri-country interia ring, centerforce clutch, terra-low NP231 Conversion, Dana 44 swap with Auburn EcTED limited slip-elec. lock, 5" procomp lift, 33s Procomp XT's, Warn 8K winch, lots of armour, terrflx belly up skid....

My latest mod was a turbo and FTC1 split second ECM. I am running about 7 psi of boost and new injectors off of a 2.5L Turbo Volvo S60R, the Turbo is a Garett T3, the exhaust is Pacesetter into a 2 1/2  down and outlet through a Thursh muffler and magnaflow cat.

I am having some some problem with the FTC1. After installing it the jeep ran great no predet except at higher rpms underload and a slight tip in heistation from stop.  I honestly have not yet tried to tune it as i wanted som advice. I contact Mark at Split Second who gave me some pointers... but I wanted some specific jeep experence and there appears to be some Turbo experence here. I know I need to leave the 500 RPM range cells alone, but Mark says I should use the same values for the 1,000 to 8,000 RPM ranges.

The jeep misfired last night and set an MIL last night and began to predetonate at all boost levels and RPMS. The engine didn't suffer any damage.  It idles fine and in neutral it runs through the RPM range without noise. SO I supect that the FTC1 goes into limp home mode with a DTC set? I will bring a scanner home tomorrow from my shop.

Any pointers on FTC1 Cell values or suggstions?

[sharpxmen]

Hey everyone,

I was searching the net for help on my FTC1 tune and found the site. I am a long time jeeper and currently have a 97 TJ 2.5L AX5. I am running a 5lbs tri-country interia ring, centerforce clutch, terra-low NP231 Conversion, Dana 44 swap with Auburn EcTED limited slip-elec. lock, 5" procomp lift, 33s Procomp XT's, Warn 8K winch, lots of armour, terrflx belly up skid....

My latest mod was a turbo and FTC1 split second ECM. I am running about 7 psi of boost and new injectors off of a 2.5L Turbo Volvo S60R, the Turbo is a Garett T3, the exhaust is Pacesetter into a 2 1/2  down and outlet through a Thursh muffler and magnaflow cat.

I am having some some problem with the FTC1. After installing it the jeep ran great no predet except at higher rpms underload and a slight tip in heistation from stop.  I honestly have not yet tried to tune it as i wanted som advice. I contact Mark at Split Second who gave me some pointers... but I wanted some specific jeep experence and there appears to be some Turbo experence here. I know I need to leave the 500 RPM range cells alone, but Mark says I should use the same values for the 1,000 to 8,000 RPM ranges.

The jeep misfired last night and set an MIL last night and began to predetonate at all boost levels and RPMS. The engine didn't suffer any damage.  It idles fine and in neutral it runs through the RPM range without noise. SO I supect that the FTC1 goes into limp home mode with a DTC set? I will bring a scanner home tomorrow from my shop.

Any pointers on FTC1 Cell values or suggstions?

how do you tune it - do you have a wideband O2 logger of any sort? Innovate just released a new product, is called MTX and has programmable O2 outputs but you would also need at least an SSI-2 in addition to that (to log your MAP and rpm at least, keep in mind that FTC1 will output the modified value for the MAP reading so you might need another 2bar map sensor to get the real MAP reading unless you calculate the output based on your modded cells). The MTX looks great for the price compared to LC1 but has a couple of less features (doesn't seem to support instantaneous output on the analog O2 outputs and the error can only be programmed as 0v and not high impedance - not sure if the latter has any importance though), i didn't personally use the MTX so i cannot speak of it first hand, i have an LC-1, the advantage of the MTX is that it already has a programmable gauge for the same price as the LC-1 which doesn't have one.

Since you have an OBD2 you could also use a scanner and watch the fuel trims but you'd be limited to the narrowband output not to mention the challenges in open loop.

Without any log data would be fairly hard to tune your system accurately.

[turboTJ]

The FTC1 is programed with a propirety software and a connection using a 9 pin serial port cable. The software enables your to control injector pulse width and injection timming by altering fuel maps.

http://www.splitsec.com/

[sharpxmen]

 i know what FTC1 does, i have one. You will need a way to know where your AFR is at for various table cells MAPxRPM and adjust the modifier value in that cell according to your log (increase or decrease the output so the AFR hits your target). The problem is you can't guess.

so that's why I asked how do you tune it. SSec guys can give you a predefined table which can be a relatively ok starting point but you still need to do your own tuning based on your injectors and fuel pressure, if you're way off on the AFR you might need to change injectors or alter your fuel pressure (latter is more difficult on a TJ but there are solutions for that as well).

[st.chevrolet]

turboTJ  No offense but the SplitSecond  FTC-1 is not an ECU or ECM as you call it, it is a piggyback Fuel/Timing calibrator which modifies the signal to the stock ECU. And regardless of what you've been told don't hold your breath about getting a Jeep ECU re-flashed.
As far as tuning read this: http://www.splitsec.com/technotes/Piggyback_Tuning.pdf  to fully understand what Sharpxmen is trying to tell you, and what it requires to tune your setup.
I have not turbo'd an OBDII 2.5 but am quite familiar with a turbo'd OBDI 2.5 and in my opinion you'll need some form of intercooling either an intercooler or chemical intercooling (water/methanol injection) which is what I use and also has additional benefits. http://www.alcoholinjectionsystems.com/a11/116+-Octane-With-Water-Injection!/article_info.html
Once the FTC-1 is all setup I think that's the best way to go as you'll have more control over your AFR.
It will take a lot of trial and error to get it tuned right throughout the rpm ranges but it will be well worth it.
Good Luck
Sean

[jfrabat]

Sean and Sharp,

So where do you recommen d getting the split second from?  Any place cheaper than the rest?

By the way, Sean, I am still debating which way to go, if water-methanol injection or intercooler.  Which tank do you use, where is it mounted, and how often do you need to refill it?

[sharpxmen]

Sean and Sharp,

So where do you recommen d getting the split second from?  Any place cheaper than the rest?

By the way, Sean, I am still debating which way to go, if water-methanol injection or intercooler.  Which tank do you use, where is it mounted, and how often do you need to refill it?

directly from Split Second is you safest bet. But i would ask for one with O2 modifier, I didn't get one like that and I'm not sure if they have one for the Jeep (i think i saw it somewhere though so it doesn't hurt to ask). that way you can adjust your AFR when in closed loop as well once you start getting boost or you risk it to be too lean. Or you can go with a programmable O2 but the downside is that you'll enrich the mixture all the time which would hurt your mpg quite a bit (not that our Jeeps have great mpg anyway).

there are some models that have programmable control output too so you could control water/meth injection straight off the Split Second unit, but then again I'm not sure if the one compatible with Jeep PCM has that feature.

[st.chevrolet]

Felipe I bought my PSC1-002 & ARM1 (AFR meter) directly from Split Second.
I do not recommend going with an intercooler only, unless you want to start playing with timing which will
require using a SplitSecond FTC1 (Fuel/Timing calibrator)(Sharp uses this) instead of the
PSC1-002 (Fuel calibrator).
Water/Methanol Injection has a lot of additional benefits over an intercooler.
Read:http://www.alcoholinjectionsystems.com/a11/116+-Octane-With-Water-Injection!/article_info.html
also:http://www.alcoholinjectionsystems.com/a10/Knock-Knock.-Who-is-the-there...-Detonation!/article_info.html
Ideally both an intercooler & water/meth. would be better yet. However I have not yet found the need to add an intercooler to my YJ, the Water/Methanol injection & PSC1 have allowed my YJ to run like it came from the factory with the turbo. As far as my water/meth. tank its 3.78L and needs filling approx. once a month,
I will email you pics of my setup its simple an cheap.
Sean