How To: Build your own 4.0L turbo Cummins (Beware...170+ pics)

[kastein]

I think you may not know how to calculate mileage.

 

[yossarian19]

Another consideration:
Increasingly tough emissions requirements mean that the super-thrifty Honda engines of yesterday couldn't be sold as a new car today. Oxides of nitrogen, a greenhouse gas, are made up around 2,000 degrees - which also happens to be (I think) really efficient combustion temperatures. With nitrous oxide emissions having to decline every year, automakers have to get more fuel economy out of less potential, or find a way to clean it all up before the tailpipe.

Gearing wise.. it all depends. My 30s & 3.55s got me 22 mpg across the Great Plains on one trip. My 31s & 3.55s would probably get me 21 - 22 on the same trip. Around town, my mileage is around 13.75 on the last tank. The factory setup w/ 28s & 3.55s is a good compromise and functions really well on the street & the highway but is by no means the only acceptable gearing.

 

[Begster]

I think you may not know how to calculate mileage.

X2.

I don't see how you think your 87 XJ that probably gets 13-14 mpg can out perform newer cars that have 26+ mpg city, and 30+ mpg highway. Are you thinking you're getting better gas mileage because you guys have to fill up the same amount of times per week or something?

 

[eflores]

Um my 89 xj's have all gotten 20 ish mpg...

 

[Super mud]

X2.

I don't see how you think your 87 XJ that probably gets 13-14 mpg can out perform newer cars that have 26+ mpg city, and 30+ mpg highway. Are you thinking you're getting better gas mileage because you guys have to fill up the same amount of times per week or something?

I was comparing to similair cars like the i6 trailblazer my mom drives. Actually pretty close in mpg after I researched it but for a 20 year difference kind of lame. Also I was talking about all cars for example Honda has a new hybrid (Crz) that only gets 38mpg while in the 80's the civics were getting over 40.

 

[RedChuck]

yeah but eco cars were go carts then and now they are significantly bigger and heavier with lots of new techy bits in them. the difference is in how much car you get with the same mileage. just look at the evolution of one of those cars

but... if you wanna discuss this start a new thread don't high jack the turbo build thread

boostworks did you get it on a dyno yet? i wanna see some numbers.

 

[XJEEPER]

Dyno...dyno....dyno.....dyno.....

My rig is no longer my daily driver, so a winter power add project is on my radar.

 

[Finaltheorem47]

Dyno! Dyno! Dyno! Dyno! Dyno!

 

[casual]

A few questiions for turbo sizing! Theres 2 guys I've been watching, 1 is running a .60 comppressor and .48 exhaust housing, the other is running a .50 compressor & a .63 exhaust housing. Both running 8lbs but there rigs are so different you can't gauge spool time lol, 1 is on 31's the other ones 42's...
I wanna do a boosted 4.0 for my daily driver.. probably 6-8lb..possibly 10lbs if it'll take it without detenation. I have a 5speed, with 3.55's and 31's..3" lift. Just looking for a fun fast setup. Using a SAFC II/Neo to tune it.
Any advice or suggestion n which turbo to go for and help or advice??

My full build is...60 over bottom end, o deck .048 quench. maybe just a tad higher or than stock compression..but with the tighter quench it wouldn't matter. Ported head, stock cam..Looking at the comp 200 but haven't decided yet.

 

[Boostwerks.com]

Personally, I'd go with the larger A/R housing and would even go larger if possible. My Borg Warner has a .63ar but also has a P trim turbine wheel which is much bigger than the standard "stage 2 or 3" T3 wheel. Going smaller will only choke the motor more in the upper RPM's as well as making it easier to be in boost all the time so the mpg will suffer.

Typically I like a turbine housing to be fairly large and laggy so that it's possible to drive around without even getting into boost. Even out of boost the turbo will increase low rpm VE which in turn boosts torque all while keeping the AFRs in the 14.7 area. This can also help you pass emissions, and allow the most power on pump gas.

Overall I've been VERY happy with my Borg Warner 57 Trim T3/T4 and highly reccomend it. I've also had very good luck with Garrett turbos as well. Either way I'd shoot for a mid size T3/T4 with a minimum of a .63ar housing.

Lastly I'd stick with the stock cam if your looking to turbo your 4.0. Most aftermarket cams will just raise the RPM in which peak torque occurs while doing little to nothing for low RPM torque.

 

[KJurasek]

Impressive work. Thanks for the insight on the AEM controller. I will be looking into it for my Piggyback.

 

[jeepboy381]

Where is the dyno slip?

 

[XJEEPER]

Bump for updates. My front D30 polish has been recently installed, and the rear 8.25 shall be thrown in soon as well. It's worth noting since I'll be off to the dyno as soon as it's in.

Bryson, what does a dyno session cost in CO?

 

[Boostwerks.com]

It's still on my "to do" list.

My customer's orders will always come first. Not to mention my day job and wife. $ is great, but so is a life.

My avatar selection is no coincedence.

 

[h-townxj]

Hey Boostwerks do you happen to recal which HEX file your sing on your tune. im curious if mine is causing my stalling problems. this has all started ever since i reflashed it. but i also had a bad battery at the time. also used an old charger afraid i might of burnt the ECU but trying to rule out other problems first.

 

[gradon]

I'm using the x3.81.hex, but mine's a 96 obd2(transition year that still used obd1 type sensors), so might not be as picky as the 97+ can bus obd2.

 

[h-townxj]

I guess I ment hex file oops. I left what was in mine on it. Then the other day I changes to 107 and then that's when all my sensor issues started

 

[classicherokee98]

First off perfect build boostwerks!! ive been thinkin and planing a turbo build for a while now and you helped me with some bumps i came a cross like the tuning. this might be a stupid qus. but i live were the lovey emisson is a plug in, and was wondering if you are or did trip a SES light? some insight would be great
~thanks~

 

[Talyn]

I guess I ment hex file oops. I left what was in mine on it. Then the other day I changes to 107 and then that's when all my sensor issues started

You meant the Z hex file. I'm running the Z107 on my 2000 XJ and it works fine aside aside form a cold start issue that isn't related to the AEM. I originally had the Z110 installed... bad idea. The PCM did not like that at all. Remove the AEM from the loop and install the bypass plug that came with it to diagnose if its the AEM or PCM or something else.

 

[h-townxj]

Ya I've tried that the only issue has been with my 36lb injectors it runs so rich it's hard to tell. I guess I'll have to change em again... Such a hassle lol stupid top mount sc