Faster Jeep

[Ed A. Stevens]

so after i get a stroker and fix what needs to be fixed replacements etc. this is what i plan to do ... let me know whats wrong with it or what should i change or get rid of...

Cold Air Intake
Gibson Cat Back Exhaust
Gibson Shorty Headers
Helix Throttle Body Spacer
MSD Ignition
8mm Plug Wires
Bosche Platinum Series spark plugs
Upgraded Fuel Pump & Lines

Start with what will work with the stock 4.0L or the stroker:

Cold Air intake with high flow filter == OK

Gibson Cat back == OK, but find a good muffler shop and get a quote for a 2.5 pipe from the header to the Cat, a 2.5" cat-converter, a 2.5 muffler (your choice) and 2.5" or 3" pipe out to the rear bumper (there is no magic to the Gibson name or product that cannot be improved upon by a good muffler shop).

Gibson header == OK, but almost everyone trades up to a Borla or Kolak header (a header is good, just buy it only once).

TB Spacer == I believe it's snake oil (it's your money, better spent on a larger TB).

MSD Ignition == The XJ ignition is as good (save your money -- and I have MSD's on all my older cars because MSD equipment is great, but not needed on an XJ).

8mm wires == Yes, Yes, Get a quality brand (Magnacore, Sorenson, MSD, Moroso, even Splitfire).

Bosche Platinum Plugs == Yes, just not +4's, Get regular style platinum plugs (the platnium is for wear resistance, learn about plug heat ranges to select a good plug for the conditions you drive, because getting the correct plug heat range is more important than the style of plug or platnium).

Fuel Pump & Lines == save your money, because the factory pump and fuel system can easily 30#/hr injectors and it is very unlikely you will ever exceed it's capacity.

The little needs of a stroker (the process posted by Bones) is what to expect for any high performance build up. The costs exceed the budget, the little tasks & items end up costing more than the simple machine work and basic assembly (injectors, pushrods, port matching, valve springs & retainers, cam indexing, balancing the assembly, adjustable MAP & fuel pressure regulator, and custom accessories and mounts, etc.).

The needs of a mild 4.0L build up are similar to the stroker, or any engine build-up, it's just that most engine builders do not have AMC I6 performance experience and know about the little details that will end up costing you more than expected (my mildly built 4.0L in my 88 has all but a few of the mentioned modifications needed for the stroker).

I would make an effort to ask around to identify a real drag strip in the area? The BS stops when the track timers start, and there is no better way to compare not only who won, but by how much (and where on the track the winner had an advantage: start reaction, 60 foot, 1/8th mile or 1/4 mile top-end). The cost to run is cheap, and it's legal, and safe (and girls dig real race drivers who prove it on the track). Get some Steam for that Bling and be a Champion.

 

[Eagle]

http://www.cnn.com/2003/LAW/05/19/ctv.drag.race.trial/index.html

As Ed Stevens wrote -- go to a legal drag strip.

 

[MudDawg]

I very strongly agree with the GO TO THE DRAGSTRIP!!!! idea...at the track, the clocks tell the true story. And if you test (at the track) you will finds out how well your tuning skills are progressing. I have been dragracing for over 30 years, mainly on Motorcycles with ET and MPH in the high 7 zone at 160+...I know or knew 9 people who over the years bit the big one racing on the street. Some ride bikes, but most drove cars or trucks.

As for myself, I have discovered the pleasure of going slow and getting muddy

 

[XJguy]

Another tip....the day you do race, gut your interior. Take everything you can take out of the inside while still allowing the Jeep to function right, including the carpet, this will save you at least 200lbs. Also do as I did, fabricate a smooth whole body under tray, make sure the materials you select are not flamable, much aerodynamics can be achieved with a slick underbelley. Also remove the wiper arms and your rear view mirrors, less wind resistance. As far as weight and aerodynamics there is mcuh tah can be done, just remeber if it does not make the engine go faster, make you safer, or help cut the wind..then its not needed. If you have tinted windows your buddies wont even know what you did on the inside, just dont let them take a peek. A conservative shot of nitrous would not injure your engine and would give you that last bit of HP that may mean a win or lose.

But back to what I posted the other day, a blower is the best bang for the buck, and you can always resell it or transfer it to another car should you want to. Turbos are better for top end than a 1/4 mile drag strip. They are also more expensive due to all the custom exhaust work they necessitate. Personally I would not stroke the 4.0, high revs are better suited for shorter stoke; forced induction is the way to go. Stroking is ideal for offroaders, not if you want to rev things up on a drag strip.

XJguy

 

[TriZZle904]

aight so ill try to find a drag strip somwhere near town... cause i would be interested in accurate times... so what next... who likes the above plan.. what needs to be changed... ???

 

[Bones]

1986xj, "His engine is way overbuilt, sounds like it was built for running in a JEEPSPEED race series XJ. Nothing wrong at all with that, he's just spent a lot more so he'll be able to squeeze those last few ponies out of his (those last few HP are always the expensive ones )"

Mike,
This is what I mean by a misconception about a stroker build. My engine is not overbuilt. Yes, I did add some things to try to make it more reliable, but I didn't do anything to squeeze out a few more HP. Actually I didn't even look at HP #'s while building it.

Granted you don't have to have SS valves but they were only a few $ more. I didn't need ported heads, but the porting I had done was very minor and aimed at efficiency not at top end. In all the porting was less than $200. A stock grind cam will cause pinging issues so the longer duration, bigger overlap cams are needed. In fact, I am going to a bigger cam right now because I had some ping with my torque cam I used at the rebuild. As for my remarks on the valve springs, retainers, and keepers, the valve train was one of the problems we had in my rebuild. It probably took 3-4 weeks to come up with a set of springs and related stuff that would work with the stock stem sized Mopar valves I wanted to run. I went with the stock sized valves to cut machine time but I may have been better off to have the head cut for the 2.02 valves and used Chevy parts. Yes, “stock” sometimes costs more.

As for pistons, if you are going to build a stroker for torque then you want to stay with the 4.0 rods. While people are experimenting with altering some cast pistons I think the only way to keep reliability is to use a custom set for the stroker set up. They only come forged and the cheapest I found was $600. While you can go the shorter 4.2 rods and off the shelf slugs there are quench height and compression issues related to them. Trying to work through the pinging this can cause could end up costing more than the forged custom pistons. If you don’t believe me, check out the cost of an adjustable MAP sensor from TurboCity and an adjustable fuel pressure regulator from HESCO. With the short rod stroker you will usually have to run premium fuel, which also has to be figured into the mix.

Though I didn’t need Total Seal piston rings, I was tired of blow by causing an oil slick in my air filter so I waited over a month for them to come off backorder.

The custom milling of the block and head is going to have to be done for either method of stroker build. In fact, it may be even more critical in the “budget stroker”.

The one thing I put in that wasn’t really necessary was the stud girdle. Again, I did it to help strengthen the motor and make it more reliable in the long run.

New injectors are a given. You have more CI’s to feed so you will need a bigger injector or you will run lean. It’s the same for either stroker build.

The cooling system on a XJ is already marginal. Now you are adding ponies and therefore more heat. It’s going to take a bigger radiator to keep things cool unless you are really lucky. This isn’t an optional thing for most and though it is not part of the stroker build it has to be figured into the overall cost of the package. I didn't need a $200 HESCO water pump, I could have use a $100 FlowKooler one and already had to replace it ( I was the first on the board to try one, it lasted less than one year and FlowKooler would not honor their warranty. I won’t by any more of their crap). The header wrap was done to try to decrease the workload on the cooling system, again, because of its marginal capacity. Borla is the only header manufacturer that will honor their warranty if you wrap it. I also got lucky and picked a new one up for about half the cost of retail.
What I didn’t say is that I already had a 2.5” cat and cat back set up so I didn’t figure that into the mix and as yet I have not added a larger throttle body but I think it would help (what’s another $300 bucks right?).

I’m not trying to talk anyone out of a stroker. I love the power of the motor. Ask Goatman how it did in CO last July. He was running with his foot to the floor coming up a pass while I hadn’t noticed we were climbing at the rate we were. I was running the AC, pulling my loaded pack trailer in overdrive, and was still pulling away from him.
What I am trying to do is give everyone a clear understanding of the “hidden” costs of a build and a reality check before they start tearing into their motors with visions of cheap stroker power.

Ed A. Stevens, “The little needs of a stroker (the process posted by Bones) is what to expect for any high performance build up. The costs exceed the budget, the little tasks & items end up costing more than the simple machine work and basic assembly (injectors, pushrods, port matching, valve springs & retainers, cam indexing, balancing the assembly, adjustable MAP & fuel pressure regulator, and custom accessories and mounts, etc.).
The needs of a mild 4.0L build up are similar to the stroker, or any engine build-up, it's just that most engine builders do not have AMC I6 performance experience and know about the little details that will end up costing you more than expected...

Ed, I couldn't agree more!

Bones

 

[REDXJ4FUN]

Ok lrts did in to this some more. For the most part evryone has been giving great infoand as always there is a diverse and very knolaged group of XJers here. I've been reserching turbos and home grown set up for about a year now and some of the things i've seen are impresive. and if you can do any work your self you can get alot of bang for the buck using junk yard pats but for most people that just doesent work. another junk yad option that i have seen is using a super charger off of a toyota MR2. Also building a stroker for so drag raceing isn't that bad. People have been drag raceing 4.2 l for years the main thing to think about is matching your gears to your motor. if you motor builds a bunch of low end use higher (low #s) so that your using what you have and not just turning the snot out of a motor that doesn't want to. Thers many way to to make things quicker but it deffinatly helps to have guidence from those of us who have been there broke tha and blew the money to see what can happen.

 

[TriZZle904]

very true and thanx everyone for your input

 

[cjharr]

Mike,
While you can go the shorter 4.2 rods and off the shelf slugs there are quench height and compression issues related to them. Trying to work through the pinging this can cause could end up costing more than the forged custom pistons. If you don’t believe me, check out the cost of an adjustable MAP sensor from TurboCity and an adjustable fuel pressure regulator from HESCO. With the short rod stroker you will usually have to run premium fuel, which also has to be figured into the mix.

While quite true there are alternatives. After I bought a '87 Comanche 4WD with a 5 speed at what I thought was a very good price of $450.00, the engined died 2 days later. After doing a lot of research and pestering people with tons of questions, I opted for buying a 4.6 stroker (found out after I got to Texas it was a 4.7) from Groom's Engine in Nashville,TN. The engine, additional parts (ie: motor mounts, shocks, brakes, full tuneup, Python Racing Injectors, instrument cluster with gauges instead of idiot lights, and quite of few other parts), lifetime warranty on the engine, and mechanic's labor for replacing the engine (he also replaced the clutch slave cylinder and did some other work) set me back for $4200.00 for everything (which included the purchase of the MJ and registration). The engine itself (a long block) was ~$1600.00 and $200.00 for the lifetime warranty. The stock 4.0L long block was running at $1100 at Autozone. Due to time constraints of moving, I had to buy an assembled engine. I am running 87 Octane driving it gently and 89 octane for towing and having fun. As it is, I am trying to learn how to drive the sucker without chirping the tires too much . On wet roads I can forget using 1st gear and have to be extremely gentle starting and accelerating in 2nd gear. I have met a few honda's and mazda's that were disgusted at losing to a Jeep truck. The guy riding with me was shocked that I had only used 2nd and 3rd gear to do this. Since this is my type of driving during the day to safely merge with highway traffic, I do not see this as really racing. We did do the speed on a freeway late at night and only raced up to the 70 MPH speed limit. I also strongly endorse, as mentioned earlier in this thread, doing any racing in controlled areas like a track. It sounds like this is what he is looking for more than anything else after all is said and done.

 

[Dr. Dyno]

Dino has some good common sense mods but his numbers are obtained with a handheld stopwatch...and thus his HP numbers are ballpark at best.
I'm not trying to slam Dino...he's approach is valid...his numbers just shouldn't be considered "Emporical Data"

True enough. Without actual dyno numbers, my HP numbers are at best a good estimate but the performance numbers I took are valid though. I repeated them several times to make sure of that.
After I finished doing all the external bolt-on performance mods, ported the head, and raised the CR to 9.1:1, I was still craving for more performance so I satisfied it by building a 4.6 stroker (ooooooh yeaaaaaaaaaaaaah!)
_____________________________
Dino's "Mean Green Machine"
1992 XJ Laredo 4-dr - 193k miles - 19k miles on 4.6L HO Stroker
AX15, NP231, D35c, D30

265hp@4900/325lbft@3500, 1/4 mile = [email protected], 0-60 = 5.6secs
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks

Forever in the s__t. It's only the depth that varies!