Turbo Jeep Cherokee XJ-R Build

[bjoehandley]

that is awesome! I autocross a RX7 and often wondered what a XJ would be like since I have a shell and 2wd tranny but with a rotary and 5 speed for less weight. That thing is sick, keep on ripping it up!

Just think about how many rotors that will fit under the hood of an XJ.............is there a way to build a 6 rotor Rotory engine?

 

[IXNAYXJ]

Just think about how many rotors that will fit under the hood of an XJ.............is there a way to build a 6 rotor Rotory engine?

The 787B that dominated LeMans was a 4 rotor....don't see why 6 would be a problem. Lol

http://en.m.wikipedia.org/wiki/Mazda_787B

-M

 

[PseudoSport]

Hmm, with a little work to the trans tunnel this should fit no problem. Just need to find a custom eccentric shaft.

 

[CobraMarty]

12 rotary offshore boat engine

 

[Boostwerks.com]

Hmm, with a little work to the trans tunnel this should fit no problem. Just need to find a custom eccentric shaft.

lol. I'd love to see the crankshaft. :scared:

 

[PseudoSport]

It's finally autocross season. We'll be dusting off the XJ-R and going through a few things next weekend. Last year our BOV jammed open so that will be swapped with another cheap junkyard one. Also we need to figure out what tires we'll be running since 2 of the 275 Hoosiers corded. Can't complain since we got more then a dozen runs out of a free set of discarded tires.

 

[Root Moose]

V710s? Cheaper but fast enough?

 

[Tptrsn]

Probably faster than old Hoosiers!

 

[PseudoSport]

Normally we have been trying to find stuff for cheap since tires count in our budget but I’m not sure if we’ll be bring the Jeep back to the GRM Challenge. Maybe we’ll spend a little money on it this year.

Since my teammates don’t want to bring it back to the Challenge we’ve been thinking about what to do with the Jeep. Once thing we have considered is the Grassroots Ultimate Track Car Challenge since they now have a Crap Can class. Main issue with that is one of our teammates would need a NASA license. I know Dave has done a number of track days and has been to a HPDS but has not been signed off yet. Jeff has experience too but I’m sure how much more time or money it would for either of them to obtain a license. After that we would still have to sort the Jeep and add a roll cage.

The other thought was to enter 24 hours of Lemons in NH. Since tires, brakes, and other safety stuff is free plus we don’t have to claim fair market value on the free garbage we used to assemble the Jeep we could make budget. We’d have to run a free hacked up megasquirt I fixed and sell off a few unused stock parts but it should be doable. Worst case we end up with a few BS laps but still go out and have fun. I’m also curious how many laps the turbo 6 will do before it explodes. At least It’s easy enough to throw a non turbo 4.0 back in and swap maps in megasquirt. Down side is the risk of the Jeep getting mangled is much greater in Lemons so we’ve also talked about finding a free beat up XJ and swapping some parts around.

Either way we are just kicking around ideas for now.

 

[boostamante]

It's a cheap 50 trim T3/T4.

Yes, we are running MS1 with the 3.0 board. Its a complete stand alone computer controlling fuel and spark for under $200. Currently we are running around 7 psi but have had it up to 12-13 psi with the new intercooler. As far as power we did rush to try and get it on a dyno last year but found we had a big boost leak. We were hit 6 psi then tapered down to 4 by redline. Even so we made 201hp/263tq at the wheels. Another issue we had on the dyno is we could only do WOT pulls after 3000 RPMs or the trans would kick down a gear. We have since sorted out a few issues so hopefully this spring when the snow melts off the XJ-R we'll get it back on the dyno.

Incase anyone wants to megasquirt a 91-95 Cherokee I came up with this pinout. This is for use with a 91-93 distributor and a 6 vane shutter wheel:

The k-car in the back ground is now known as the Scaries and actually came in first last year. Pat and the guys have done an amazing job wit the car and you should see it now. If you have time check out their build thread.

http://www.turbo-mopar.com/forums/showthread.php?51514-Pat-s-GRM-ScAries!

The BMW Isetta has custom control arms mounted to the factory suspension points and a mazda rotory engine in the passenger seat. It defiantly bent the rules a little but I love seeing stuff like that show up as long as its within budget.

Oh and the red Miata in the background is mine. It was a challenge car from 2009-2011 and has placed as high as 4th over all. I miss that car.

Whoah! thanks a bunch for posting this. Maybe a turbo jeep will finally happen.

Did you guys run 12 lbs of boost on the stock block?

 

[PseudoSport]

No problem, I was hoping someone might find the pinout useful even if they went with another standalone computer besides megasquirt.

Yeah we’ve had it up to 12 psi from the 50 trim T3/T4 on the stock 240k 4.0L but our intercooler and pipes are too small which makes it very inefficient at anything above wastegate pressure. We’ve look into a front mount but and came up with a few different options with larger pipes but that involved moving the radiator and cutting up the lower support. That also would have been more expensive then just welding a bunch of free crap together and hoping for the best.

 

[boostamante]

No problem, I was hoping someone might find the pinout useful even if they went with another standalone computer besides megasquirt.

Yeah we’ve had it up to 12 psi from the 50 trim T3/T4 on the stock 240k 4.0L but our intercooler and pipes are too small which makes it very inefficient at anything above wastegate pressure. We’ve look into a front mount but and came up with a few different options with larger pipes but that involved moving the radiator and cutting up the lower support. That also would have been more expensive then just welding a bunch of free crap together and hoping for the best.

Right on, not much room for a big ass intercooler in the front of an XJ. Unless, you use the intercooler as the XJ grill My plans are for 8 PSI of boost max.

ALso, did you guys get the MS system assembled or did you guys put it together as a kit?

Hope it's not too difficult for me to wire up. Im not SMRT like you guys. I'm borderline retarded... mainly in the reading comprehension dept. I prefer pics and videos.

With the MS installed is there a need to modify the fuel rail or alter it for fuel return or is that something that only needs to be done when running a FMU.

My turbo knowledge is mostly with Hondas ( 88-95's ) and so this is a tad different.

 

[PseudoSport]

We bought the Megasquirt as a kit and the average build time is about 6-7 hours. If you can solder it’s not bad to put together. Just take your time and follow the instructions and pictures. Trying to figure out how to wire it and what ignition set up you are running can be the tricky part. Then comes tuning.

Our fuel rail, pump, lines, and regulator are stock. All we did was run larger injectors and change the required fuel setting in megasquirt.

 

[boostamante]

We bought the Megasquirt as a kit and the average build time is about 6-7 hours. If you can solder it’s not bad to put together. Just take your time and follow the instructions and pictures. Trying to figure out how to wire it and what ignition set up you are running can be the tricky part. Then comes tuning.

Our fuel rail, pump, lines, and regulator are stock. All we did was run larger injectors and change the required fuel setting in megasquirt.

OK, so then with MS you dont need to modify the fuel delivery other than larger injectors.

So do you add MS to the stock harness or does it just bypass the injectors/distributor?

 

[PseudoSport]

At our power level all we had to change was injectors. You would run MegaSquirt in place of the stock computer. You can either build an adapter harness to make it plug and play which would also let you return to stock if needed or you can cut the harness like we did and solder on the MegaSquirt connector.

Some people have run is as a piggy back to the stock computer. This allows MS to control fuel and spark while the stock computer controls idle, electric fans, A/C, etc.

 

[O-Gauge Steamer]

Curious, what size injectors are you running? I had, initially, planned on being able to do an E85 tune so I stuck 40 lb injectors in my Heep. IMO, 36 lb would work just fine for my application.

But then, I am only running 7 pounds or so of boost...

 

[PseudoSport]

We are running 36 lbs injectors from a supercharged GM 3800. I've seen around 85% duty cycle at 7 psi. A slightly larger injector would be nice but the 36 lbs were free and work for now as long as we don't crank the boost.

 

[bjoehandley]

Curious, what size injectors are you running? I had, initially, planned on being able to do an E85 tune so I stuck 40 lb injectors in my Heep. IMO, 36 lb would work just fine for my application.

But then, I am only running 7 pounds or so of boost...

Let me know how the E85 turns out if you go for it, I'm trying to figure out a good and cheap way to convert my stock '98 over.

 

[O-Gauge Steamer]

At issue is the O2 sensor offset function of the F/IC. Others (ones that I hold in high regard...) have attempted to use this function without much success. The F/IC is tagged onto the line from the sendor to the PCM and attempts to override the voltage. It would be better if the signal was interrupted, processed and then sent to the PCM as is the crank/cam position sensors. Sadly, it is not.

That being said, the attempts that have been made were with the F/IC6. I run a F/IC8 so maybe it will work. Don't know...

So, for now, the E85 project is on permanent hold.

 

[gradon]

I got the F/IC6 o2 offset voltage to work in my 96 XJ with both a 6Kohm and a 10Kohm resistor. The PCM overrode the 1Kohm that the AEM instructions called for.