Stroker power issue

Performance mods and Advanced Stroker discussion.
Post Reply
LDUStrokerDXB
Posts: 6
Joined: January 1st, 2020, 9:55 pm
Stroker Displacement: 4,6
Vehicle Year: 2004
Vehicle Make: Jeep
Vehicle Model: TJ 4.0

Stroker power issue

Post by LDUStrokerDXB »

Hello guys,

I've got a 2004 4.0 TJ and I've built a Stroker with the following specs:

2004 Jeep Wrangler 4.0 Stage 3 Jeep Stroker Kit 4.6L 9.3:1C.R.
DSS 4032 Forged Dish Pistons -21cc #IC944 (Standard Piston
Set)
Hastings Moly Rings #2M4815 (standard)
Scat Enterprises 9000 Series Cast Steel Crankshaft 3.895" Stroke
#9-4.2L-3895
Clevite Rod and Main Bearings
Scat Forged Rods W/ARP Bolts (Bushed) -
Howards camshaft
Intake 273° valve lift 0.48 exhaust 279° valve lift 0.48
Lobe sep. 114° intake CL 110°
Degree of duration @ 0.05
Intake 219°gross lift at cam 0.3
Exhaust 225°gross lift at cam 0.3
Lifters - 12
Timing Set - Timing Chain, Cam Gear, Crank Gear
Pushrods - 12
Dual Spring Valve Springs - 12
Valve Retainers - Steel
Valve Keepers - 12 Valve Set
Complete Gasket Set (Felpro) Upper and Lower gaskets
Durabond Camshaft Bearings with oil control groove
Freeze Plug kit for engine Block
Melling Oil Pump
Jeep LS Oversize Valve Kit
FlowKooler Hi-Flow Mechanical Water Pump
Cylinder head Bolt Set
1996-2006 Jeep 4.0L Girdle Spacer Kit
Jeep 4.0L High Performance Fuel Injectors - 24lbs | 252cc
Borla headers
Borla cat back system
Cat replaced by a 3" pipe
Edge 62mm throttle body
Ported head
K&N Cold air intake with a new filter


Before I've pulled the engine at 80000 miles the following mods where already done and I've been driving it for 50000 miles:

Borla headers
Borla cat back system
Cat replaced by a 3" pipe
Edge 62mm throttle body
K&N Cold air intake

Now I've stroked it with all the above mentioned parts, broke the cam in with SAE 10W40 and ZDDP additive at 2800rpm but unfortunately it has a little bit more power but almost not noticeable.

I've checked the following:

Ignition timing => Adjusted with the toothpick method (outer ring from the balancer has not moved).
Compression => Measured Compression between 177 and 182 PSI on all cylinders
MAP Sensor => OK
Throttle position sensor => OK
Intake air temperature sensor => Ok
Valve Lifters => I've checked them again and they are in the middle of their operating range also no noise

The engine runs smooth and fine it just doesn't have the power I've expected (around 275 crank HP)!

I do not know what to do anymore…

Any advice would be highly appreciated.

Thanks

Frank
LDUStrokerDXB
Posts: 6
Joined: January 1st, 2020, 9:55 pm
Stroker Displacement: 4,6
Vehicle Year: 2004
Vehicle Make: Jeep
Vehicle Model: TJ 4.0

Re: Stroker power issue

Post by LDUStrokerDXB »

Hi,

I forgot to mention the 50psi fuel pressure and the 255lph Walpro fuel pump.
User avatar
Cheromaniac
I live here
I live here
Posts: 3180
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Stroker power issue

Post by Cheromaniac »

I wonder if your injectors might be a little small and causing the engine to run lean. Check the plugs and see what you find.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
aschroeder78
Posts: 8
Joined: May 25th, 2021, 4:05 pm
Stroker Displacement: 4.6
Vehicle Year: 1997
Vehicle Make: jeep
Vehicle Model: wrangler

Re: Stroker power issue

Post by aschroeder78 »

I just went through a similar issue with my new build. I replaced my injectors with some bosch 27lbhr units and it was a massive improvement. i would really look into that
LDUStrokerDXB
Posts: 6
Joined: January 1st, 2020, 9:55 pm
Stroker Displacement: 4,6
Vehicle Year: 2004
Vehicle Make: Jeep
Vehicle Model: TJ 4.0

Re: Stroker power issue

Post by LDUStrokerDXB »

Hi aschroeder78,

did you run 24lbs injectors bevor you upgraded to 27lbs?

Would it make sense to put it on a dyno and to remap the ECU with the 24lbs injectors or should I get the 27lbs injectors first of all?
Randy Bobandi
I made it to triple digits!
I made it to triple digits!
Posts: 152
Joined: December 22nd, 2020, 8:50 am

Re: Stroker power issue

Post by Randy Bobandi »

Is your 04' an Automatic? If so, that's the 42RLE transmission. It's gonna be a dog no matter what engine you put in it. That transmission has an electronically controlled torque converter clutch (EMCC) and a .69 final drive ratio. The EMCC is a function of the TCM modulating the L/R solenoid during the 3/4 shift. It was meant to soften the shift, yet all it does is prolong the shift and causes shudder and lugging. That's the last thing you want when your 4th gear is .69:1.

Either way, if your Jeep is Auto or Manual, you need to get it tuned. HPTuners is fully compatible with your ECM, you can do it yourself. Or you can schedule an appointment with your local tuner. Via manifold pressure, the factory tune only allows 24'-28' of timing at wide open throttle. That's nothing. 34 degrees is standard. The fuel table is incredibly restrictive as well. Make use of that 255 LPH pump and get the thing tuned properly.

24 LB/HR (252cc) are not sufficient. 27 LB/HR (283cc) would be a decent upgrade but you may need more injector to reach your 275HP goal. I don't know how the whole 24 LB/HR injector thing started for these engines. I wouldn't run less than 400cc on a 4.7L Jeep straight 6 engine.
LDUStrokerDXB
Posts: 6
Joined: January 1st, 2020, 9:55 pm
Stroker Displacement: 4,6
Vehicle Year: 2004
Vehicle Make: Jeep
Vehicle Model: TJ 4.0

Re: Stroker power issue

Post by LDUStrokerDXB »

Hi Randy,

It’s a 5 speed manual.

27 pounders (Bosch) are ordered once I’ve installed them we’ll put it on a Dyno and have the ecu tuned.

Thanks for the feedback
aschroeder78
Posts: 8
Joined: May 25th, 2021, 4:05 pm
Stroker Displacement: 4.6
Vehicle Year: 1997
Vehicle Make: jeep
Vehicle Model: wrangler

Re: Stroker power issue

Post by aschroeder78 »

im not sure exactly what injectors were in it before, there are no identifying numbers on them. ran great stock but serious lack of power in higher rpm and would not go over 60mph. i hear good things about messing with the ecm. if you have the availability of a dyno and can re program it im sure it would help.
LDUStrokerDXB
Posts: 6
Joined: January 1st, 2020, 9:55 pm
Stroker Displacement: 4,6
Vehicle Year: 2004
Vehicle Make: Jeep
Vehicle Model: TJ 4.0

Re: Stroker power issue

Post by LDUStrokerDXB »

Hi,

I’m quiet sure the cam timing was dot to dor when I installed it but out of curiosity would the engine run if it is one tooth off ? The engine runs very smooth, I’ve expected it to much rougher with the new cam...
LDUStrokerDXB
Posts: 6
Joined: January 1st, 2020, 9:55 pm
Stroker Displacement: 4,6
Vehicle Year: 2004
Vehicle Make: Jeep
Vehicle Model: TJ 4.0

Re: Stroker power issue

Post by LDUStrokerDXB »

Sorry, I meant dot to dot on the gears.
Post Reply

Who is online

Users browsing this forum: Ahrefs [Bot], Amazon [Bot] and 13 guests