What is the weak point of my Build

[purple_jeep]

Hi Guys,

I am finding myself wanting more out of my poor Jeep Can you look at the following build and tell me what would be your suggested changes to improve output. Now I do some offloading so don't want to kill the low rpm completely by 90% of the time its driven on the road so that comes first.

My 98ZJ stroked to 4.6L with the following build:

Build thread: viewtopic.php?f=8&t=4596&start=105

Tune: Flyin Ryan

Parts:
Icon/Keith Black IC944 Forged Jeep Stroker Pistons 0.030" oversize
Hastings Moly Rings
SCAT 9-4.2L-3895
JP performance Timing Set
Melling M81A
Comp Cams High Energy™, 252H: Cam & Lifters CL68-200-4
Stock replacement Springs
Stock Valves
ACCEL 120330 Distributor Cap
ACCEL 130330 Distributor Rotor
NGK BKR7E Plugs
Amsoil Premium Protection 10W-40
AMSOIL Antifreeze and Engine Coolant ANT1G-EA
AMSOIL Ea Oil Filters EAO42-EA
99+ Intake
68mm Throttle Body
4" CAI
Walbro 255 pump
185 deg T-stat
2.5" Mandrel Bent Tailpipe

Machine Work:
Jet Clean Parts
Magnaflux Block
Magnaflux Head
Bore and Hone Block
Assemble Rods and Pistons
Valve Job
Magnaflux Rods
Deck Block to 0
Balance rods and rotating
Resize Rods
Grind/Polish and shotpeen
Install Cam Bearings
Check Line Hone

Cheers

Chris

[purple_jeep]

I am thinking Head work, porting & polish, match intake and exhaust porst, maybe bigger valves? Might need to change the cam but would prefer to avoid if possible as thats a big job :p

What are peoples thoughts on Nitrous?

Cheers

Chris

[BADASYJ]

You would definitly get the most bang for your buck with the nitrous. A cam change would really help you out as well. The rest of that stuff is small potatoes compared to what it will produce for you.

[Russ Pottenger]

For a 90% daily driven Jeep Application I see more downside than upside using NOS.

[jsawduste]

You would definitly get the most bang for your buck with the nitrous. A cam change would really help you out as well. The rest of that stuff is small potatoes compared to what it will produce for you.

Are you really this out of touch ? Sorry but your suggestions are not very practical. You are frankly becoming annoying having to rescue folks from your comments.

Before any work on the engine think about tire size and gearing.

[BADASYJ]

For a 90% daily driven Jeep Application I see more downside than upside using NOS.

To a point I do agree Russ, but we are in a stroker performance forum here not a grocery getting mall crawlers forum. When someone asks about nitrous 99% of the time they want to race and go fast, not drive around with it on. No idea what the other 1% do, maybe huff it lol. I see he is 90% road but regardless of what he uses it for there is no comparison when it comes to the power gained to dollor spent ratio. Not to mention the downtime time saved. Just my thoughts on it, that's all he asked for.

[BADASYJ]

You would definitly get the most bang for your buck with the nitrous. A cam change would really help you out as well. The rest of that stuff is small potatoes compared to what it will produce for you.

Are you really this out of touch ? Sorry but your suggestions are not very practical. You are frankly becoming annoying having to rescue folks from your comments.

Before any work on the engine think about tire size and gearing.

The head work, port matches, and big valves will give insignificant power at low rpms.Yes those things do help and provide a well rounded system but Nitrous and a cam will be what really wakes it up.
You aren't rescuing anyone dustybrains, all you do is confuse and badger people.

Quit stalking my posts you troll....

[jsawduste]

In plain English, dumbed down to your level.

BA are you really this ignorant or dumb ?

[purple_jeep]

Chill guys

Yeah NOS is more of a "hey that would be fun" than anything else i think.

Tires are 31", Diffs are 3.55, Transmission is 42RE and NP242 transfer case. I have a Ford 8.8 with 4.56 gears I plan to install as soon as I can afford to lock and truss it.

Cheers

Chris

[Cheromaniac]

My 98ZJ stroked to 4.6L with the following build:

Parts:
Icon/Keith Black IC944 Forged Jeep Stroker Pistons 0.030" oversize
Hastings Moly Rings
SCAT 9-4.2L-3895
JP performance Timing Set
Melling M81A
Comp Cams High Energy™, 252H: Cam & Lifters CL68-200-4
Stock replacement Springs
Stock Valves
99+ Intake
68mm Throttle Body
4" CAI
Walbro 255 pump
185 deg T-stat
2.5" Mandrel Bent Tailpipe

I think you're generally on the right track Chris but I'd suggest the following changes to your build spec:

1. Custom forged pistons (Russ Pottenger or Bulltear can supply) that are slightly taller than the IC944 pistons for zero deck clearance.
2. Pocket port the head and match the intake ports to the intake manifold runners.
3. Custom cam from Russ Pottenger that allows for stock valve springs.
4. Mandrel-bent 2.5" downpipe.

As mentioned earlier, N2O is great bang for the buck but I'd consider it the cherry on the cake and it does become expensive if you have to refill the nitrous bottle frequently. The engine only has to run lean once on the giggle gas and what happens next isn't a laughing matter.

[BADASYJ]

I agree, n2o is the cherry on the pie. Its no joke and should only be used at the track or when absolutely needed. It will melt a hole in your piston if something does run afoul and an injector locks or clogs up. A dry setup would be the safest route to go though.
Good point on the gearing dustybrains. The gearing you plan on running (4.56) will most definitly give you more zip on take off and low speed wheeling but it might be a little hard to live with while running 31s down the highway. 3.73s would wake it up some as well as maintaining your lower cruising rpms and they can be easily sourced from junk yards everywhere. I wouldn't go lower then 4.10s with 31s if you do much highway driving though as your mileage and longevity will suffer.

[jsawduste]

I agree, n2o is the cherry on the pie. Its no joke and should only be used at the track or when absolutely needed. It will melt a hole in your piston if something does run afoul and an injector locks or clogs up. A dry setup would be the safest route to go though.
Good point on the gearing dustybrains. The gearing you plan on running (4.56) will most definitly give you more zip on take off and low speed wheeling but it might be a little hard to live with while running 31s down the highway. 3.73s would wake it up some as well as maintaining your lower cruising rpms and they can be easily sourced from junk yards everywhere. I wouldn't go lower then 4.10s with 31s if you do much highway driving though as your mileage and longevity will suffer.

See BA, I`m not a bad guy but you need to tailor your responses to the subject matter. This isn`t Drag Racer Weekly it`s Jeep Strokers. Some of your responses could be better thought out. Not stalking you but following a topic of interest, just like you.

Your absolutely correct that NO2 properly introduced is hands down one helluva hit. It would be, however, not very practical for a typical stroker based application.

Gearing is often an overlooked option. This link will allow you to play with the numbers and come up with a combination that might be helpful in your quest for power. A customer of Russ`s and friend of mine runs a WJ with 35`s and 4.56`s. While I haven't run the numbers the owner is very pleased with how it performs.
http://www.grimmjeeper.com/gears.html

Respect that you don't want to get back into the engine. If it does becomes an option the comments Dino made would help quite a bit.

[purple_jeep]

I do want to goto 33" tires hence looking at the 4.56 ratio.

I think you're generally on the right track Chris but I'd suggest the following changes to your build spec:

1. Custom forged pistons (Russ Pottenger or Bulltear can supply) that are slightly taller than the IC944 pistons for zero deck clearance.
2. Pocket port the head and match the intake ports to the intake manifold runners.
3. Custom cam from Russ Pottenger that allows for stock valve springs.
4. Mandrel-bent 2.5" downpipe.

As mentioned earlier, N2O is great bang for the buck but I'd consider it the cherry on the cake and it does become expensive if you have to refill the nitrous bottle frequently. The engine only has to run lean once on the giggle gas and what happens next isn't a laughing matter.

For #1 I did have the block decked to zero deck so is that the same thing?

For #4 I do have a 2.5" Mandrel-bent down pipe, actually whole exhaust including opening up the output flange on the header, sorry for the confusion.

For #2 and 3 thats I guess what I am looking at doing. Is it about a 50/50 split in potential improvements or is one likely to provide more than the other.

Cheers

Chris

[jsawduste]

Chris, consider adding a little more cam via a higher ratio rocker arm. Stock is a 1.6 ratio and Russ can se you up with 1.7`s. You net a couple degrees of duration and increase the valve lift with out having to do a cam change.

Your at a 433 lift now. Changing the rockers will bump you to 462.

Just bought a set from him and plan on doing that to my personal stroker. My experience is that I ought to feel the most gains down low and be able to hold the top a few RPM longer. Not a bunch but enough to hopefully feel.

Standard rules of engagement to make sure you have the travel and pressures in your springs to handle the extra lift.

[Cheromaniac]

For #2 and 3 that I guess is what I am looking at doing. Is it about a 50/50 split in potential improvements or is one likely to provide more than the other.

Head work will reap benefits even with the stock cam so definitely worth doing. Higher ratio roller rockers will have a further additive effect by opening the valves further and for slightly longer.