Turbo MJ parts list

[ghetdjc320]

Hello all,

 

Have been playing around with the idea of adding a turbo to my built 4.0. My build thread has most of the motor specs so I won’t go into detail. My MJ is a 91 and I had originally thought of going the supercharged route. However, I prefer the adjustability of the turbo and also wanted to run an intercooler. I also want to keep my ac and a turbo just has more placement options as well. I plan on running the boostwerks turbo manifold but want to get suggestions and feedback regarding fuel and timing control. I plan to keep the stock ecu and am thinking of several options:

1. Split Second FTC1 (Pricey but control timing and fuel in boost)

2. Split Second Auxilary injector (would add fuel in boost but would not control timing)

3. Running a rising rate fuel pressure regulator to manually add fuel based on boost

 

Not sure which one of these options would be best but I’m looking for any first hand experience you may have. Looking to run a max of 10lbs of boost and I’m at sea level. Also looking for turbo size recommendations. Seen different views about going with a t3, t3/t4, 50 trim, 60 trim. Any feedback on what has worked for you? I like the idea of a water cooled turbo also (not the intercooler, the actual turbo). I am not considering an engine swap or any other options other than turbo at this point. I do have experience setting up stand alone fuel injection and can do basic tuning. Other than that there is really no Dyno tuning here on Guam so I would likely have to do a remote tuning session with splitsecond to get everything tuned correctly. Whatever input you can offer is much appreciated.

 

Thanks

[Dzimm]

Pretty much everyone will tell you to do an engine swap haha.  I don't think anyone on here has put a turbo on a 4.0l.  The info I've been able to find has come mostly from the pirate4x4 forum.

[mnkyboy]

If you are on Facebook, check out the boosted 4.0 owners club, boosting a 4.0l isn't uncommon and there's a ton of information on there.

 

For your OBD1 4.0l your kinda limited on options, I think something like Megasquirt will be your best bet for tuning,most of the split second stuff is only for the OBD2 ECUs.

 

I currently run a 91 ECU on my MJ and it's getting by but a standalone would be significantly better.

I'm working on going with Speeduino,but I'm finding that even though it's similar to Megasquirt, it is a bit less user friendly.

 

 

 

 

[ghetdjc320]

I contacted an eBay seller who is selling turbo manifolds for the XJ along with water cooled turbos. He seems to know his stuff well. He informed me that they are working on an adaptor harness that will allow us to run a newer obd2 ecu in our old obd1 trucks. Interesting concept. I’ve attached his message for reference. 
 

 

[ghetdjc320]

2 hours ago, mnkyboy said:

I currently run a 91 ECU on my MJ and it's getting by but a standalone would be significantly better.

I'm working on going with Speeduino,but I'm finding that even though it's similar to Megasquirt, it is a bit less user friendly.

 

 

2 hours ago, mnkyboy said:

 

 

 

 

What kind of boost are you running on the stock ecu? Any upgrades to fuel or timing?

[mnkyboy]

7psi on a stock ECU with a MAP adjuster and 24lb injectors, I also got an adjustable FMU but haven't installed it yet.

 

 

 

 

[mnkyboy]

Here's my truck, it's running a 2.5l 4banger and turning 37s.

 

 

[ghetdjc320]

Nice! The bobbed bed is a nice touch also. Split second recommended the ftc1. It would be spliced into the injector outputs and distributor outputs at the harness and has an internal 2 bar map. There are 2 map tables. One for timing and one for fuel. It sounds like that sort of setup would work but I have no one here who can dunk it to really get it tuned

[ghetdjc320]

Do you have an afr gauge? If so, how is it running?

[mnkyboy]

I do have a wide band, under boost the AFR stays around 12:1-13:1 which is not great but safe for lower boost,especially with my overkill intercooler set up.

 

I bought the FMU to see if I could get it a little richer but then bought the stand alone, if I don't get the Speeduino running on it soon I may toss the FMU on for a while.

 

[ftpiercecracker1]

1 hour ago, mnkyboy said:

overkill intercooler set up.

 

 

 

Does such a thing exist?

 

Also, why did you stick with the 2.5? From what i understand a boosted 2.5 has about as much power as a stock 4.0

[mnkyboy]

18 minutes ago, ftpiercecracker1 said:

 

 

Does such a thing exist?

 If one does exist, I've got it. I didn't want any problems at low speed on the trail.

 

There is a 4 gallon reservoir/ice box in the bed with an electric water pump, it moves fluid through copper tubing up to a front mount bar and plate style heat exchanger behind the grill, then through a laminova water/air intercooler under the supercharger, and through more copper tubing back to the reservoir.

 

And yes the system is grounded and has an anode in it to combat galvanic corrosion.

[ghetdjc320]

1 hour ago, ftpiercecracker1 said:

 

 

Does such a thing exist?

 

Also, why did you stick with the 2.5? From what i understand a boosted 2.5 has about as much power as a stock 4.0

I’d say at 7 psi he is putting out more hp than a stock 4.0 on the top end. 

[ftpiercecracker1]

38 minutes ago, mnkyboy said:

 If one does exist, I've got it. 

 

 

What are your intake temps? 90°? 

 

I just had a thought. Assuming all the plumbing necessary is done, if you submerged your a/c evaporator (thing IN the cab) in your water tank would that not continuously chill the water?

 

 

14 minutes ago, ghetdjc320 said:

I’d say at 7 psi he is putting out hp than a stock 4.0 on the top end. 

 

I assume you ment to say more hp?

[Smokeyyank]

http://www.boostwerksengineering.com/40L-Turbo-Manifold-_p_17.html

 

Check out boostwerks. Id love a boosted 4.0 have toyed with the thoughts but same issues always come up. Intercooler and cooling. So far the most effective way I found was a remote mount turbo as it moves the turbo out of the engine bay reducing heat and allows a smaller intercooler. 

[mnkyboy]

I haven't installed an IAT gauge yet so not sure on intake temps but after hours of wheeling on hot summer days the intercooler is still cool to the touch, it would be interesting to get some actual temp readings.

 

I stuck with the 2.5l mostly to see what I could do with it, I figure if I get tired of playing with it I can swap something else in since the rest of the truck is already built to handle it, the truck has an AX15 in it so a 4.0l or something would be fairly easy to swap in.

But think the little 2.5l actually works pretty good in a wheeler, 2.5l trucks are balanced better than the very nose heavy 4.0l trucks which works pretty well offroad.

When the truck was still naturally aspirated it could hold it's own with 4.0l rigs on the road,it surprised a few 4.0l owners.

With the supercharger it feels considerably more powerful than my 4.0l 5spd XJ.

 

 

 

 

 

 

 

 

[ghetdjc320]

2 hours ago, Smokeyyank said:

http://www.boostwerksengineering.com/40L-Turbo-Manifold-_p_17.html

 

Check out boostwerks. Id love a boosted 4.0 have toyed with the thoughts but same issues always come up. Intercooler and cooling. So far the most effective way I found was a remote mount turbo as it moves the turbo out of the engine bay reducing heat and allows a smaller intercooler. 

I have a hood scoop that would work well for a low profile Intercooler possibly or I could use a water to air cooler. Boostwerks is what I was planning to use for the manifold. I also like that it located the turbo nicely under the intake manifold for a clean install. My biggest concern at the moment is fuel and timing. Also though about just adding a 7th injector under the throttle body like boostedtech does with their supercharger setups. 

[ftpiercecracker1]

Can someone explain to me why the 4.0 can only handle such minimal boost? 

 

Ive heard talk about the HG being pushed out, but i just can't wrap my head around that because the clamping force exerted by the studs across the head must be equivalent to thousands of pounds of pressure.

 

 

How much could the boost be increased if you could get a solid copper gasket? Grooves and O-rings?

 

[mnkyboy]

Seems to be mainly tuning issues, people blow up their engine and blame the engine.

 

There's people in the boosted 4.0l group exceeding 20psi

[ghetdjc320]

6 hours ago, ftpiercecracker1 said:

Can someone explain to me why the 4.0 can only handle such minimal boost? 

 

Ive heard talk about the HG being pushed out, but i just can't wrap my head around that because the clamping force exerted by the studs across the head must be equivalent to thousands of pounds of pressure.

 

 

How much could the boost be increased if you could get a solid copper gasket? Grooves and O-rings?

 

It can be boosted beyond that. From what I’ve seen hg failure occurs somewhere around 10-12p. Lbs of boost. I am running a cometic mls gasket with the easel rock aluminum head and arp bolts. My engine should be able to handle more boost but I really want to dial in my tuning to squeeze out the best performance vs just increasing boost pressure. I’ve been reading into MegaSquirt to see what all would need to be done and it seems very straightforward. I may start with the MegaSquirt first and get it tuned we’ll then add the blower

[Smokeyyank]

Megasquirt is a good platform to do your tune off of. As for the intercooler issue i was mentioning the problem is the lack of airflow and then getting heat soak especially if you're crawling. If you are just cruising around town probably not as much of an issue. Water cooled IC can work just have to route it correctly. Can also use a water menthol kit or  NOS intercooler spray kit. 

[A-man930]

I thought long and hard about this exact topic.  Here are some of my thoughts:

1. The 4.0 is an afterthought in this chassis (originally had a GM V6); this is what led to the silly radiator arrangement and cramped quarters.  
2. iron head 
3. non-crossflow head
4. exhaust has to cross over to the passenger side at some point...
5. aforementioned tight quarters for a charge-cooler

I was going to go with megasquirt, use coils from an LS, maybe use e85, etc. etc.

 

I never did any of it.  

 

I'm putting a TDi in it instead.  

 

That being said, I'd love to see it done and I'm sure all of these problems can (have been) overcome.  Best of luck and please post your progress!!

[WeezyBlue]

Around 8psi is when you can start seeing head studs stretch, hence the blown head gaskets.

 

7psi on a 4.0 will make it feel like a decently powered V8. A turbo 2.5 sounds like a lot of fun. 

 

I think if you're going the homebrew route, a turbo is easier than a supercharger.

 

I've had problems with my split second on my 05 TJ but that's an NGC PCM and so far removed from the old 2.5 that it's not even relatable in terms of issues to overcome.

[ghetdjc320]

4 hours ago, WeezyBlue said:

Around 8psi is when you can start seeing head studs stretch, hence the blown head gaskets.

 

7psi on a 4.0 will make it feel like a decently powered V8. A turbo 2.5 sounds like a lot of fun. 

 

I think if you're going the homebrew route, a turbo is easier than a supercharger.

 

I've had problems with my split second on my 05 TJ but that's an NGC PCM and so far removed from the old 2.5 that it's not even relatable in terms of issues to overcome.

Mine should be safe to 12-15 psi or possibly higher. I’m running the aluminum head with all arp fasteners and a cometic hg

[krustyballer16]

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