Stroker numbers nowhere near what I thout it should be.

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jmarsh1082
Posts: 2
Joined: June 5th, 2023, 9:49 am
Stroker Displacement: 4.7
Vehicle Year: 2003
Vehicle Make: Wrangler
Vehicle Model: Rubicon

Stroker numbers nowhere near what I thout it should be.

Post by jmarsh1082 »

Hi, everyone!
I'm first time poster. Also Its my first Tj build.
Im looking for some opinions on my stroker build. I feel my dynoed HP at the wheel is way to low. I purchased most the parts from Clegg. I had the stroker built at a local machine shop.
I hope this doesn't come across as being paranoid, however the parts I built I feel should have gave me much more HP.
Im wondering if they actually madie it into the motor.
Please advise.
List of parts:
Stage 3 Hypereutecitc piston .060 over.
Hasting moly ring.
Scat Crankshaft.
Scat 4340 connecting rods.
Clevit rod and main bearings.
Balanced Rotating assembly.
Stage 1 cam kit with howards lifters.
Clegg/ harland, roller rocker arms
24lb injectors.
62mm throttle body.
FlowKooler water pump.
Melling oil pump.

Work done:
I wont list every thing.
Resurface block deck.
Resurface cylender head.
Ballanced parts.
Port heads.
Bore to .060 over.
Valve grind.

Dyno results:
Compression test: 160 per cylinder.
Last dyno pull,
hp - STTPrw Max 171.1.
STPTrq Max 220.5.
Lamb_1 Max 0.875.
I'll be honest I have no idea if these numbers are good or bad.
Im a home mechanic, learning as I go.
Im wondering if my cam is not aggressive enough.
Thank in advance!
Randy Bobandi
I made it to triple digits!
I made it to triple digits!
Posts: 156
Joined: December 22nd, 2020, 8:50 am

Re: Stroker numbers nowhere near what I thout it should be.

Post by Randy Bobandi »

jmarsh1082 wrote: June 5th, 2023, 10:24 am I feel my dynoed HP at the wheel is way to low.
170 wheel HP. What tire size? What transmission and gear ratio? What fuel? Max HP RPM? Max Torque RPM?

You only have 24# injectors, basically stock TJ. Probably a stock TJ fuel pump. Probably a stock TJ ECU.

Stock fuel system + stock ECU = Stock power. You could put a 481x and a Lenco in your TJ, with stock fuel and ignition it'll make 200 HP.
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Cheromaniac
I live here
I live here
Posts: 3190
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Stroker numbers nowhere near what I thout it should be.

Post by Cheromaniac »

jmarsh1082 wrote: June 5th, 2023, 10:24 am Last dyno pull,
hp - STTPrw Max 171.1.
STPTrq Max 220.5.
Your numbers actually look OK for a mild stroker.
What transmission do you have, and which gear was used for the dyno pull?
Also what axle gear ratio and what size tires are you running?
All of these factors will have a bearing on the dyno results.
BTW, the stock fuel pump is fine.
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:
jmarsh1082
Posts: 2
Joined: June 5th, 2023, 9:49 am
Stroker Displacement: 4.7
Vehicle Year: 2003
Vehicle Make: Wrangler
Vehicle Model: Rubicon

Re: Stroker numbers nowhere near what I thout it should be.

Post by jmarsh1082 »

Hey, thanks for the reply!
I'll try to answer all the questions.
I believe it was a 5th gear pull at 110 mph.
Its a 03 Rubicon so 4:10 stock gears?
33 inch tires.
Running premium fuel.
I have a fuel regulator delete kit with after market fuel pump.
And a fuel regulator.
The jeep has high flow exhaust a bigger air intake I think 63mm. Id have to go look.
AFE air box. Banks headers.
My goal was something like a golen engine hp and tourke.
It ended up costing way more for way less.
Thanks for your guy's feedback.
User avatar
Cheromaniac
I live here
I live here
Posts: 3190
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Stroker numbers nowhere near what I thout it should be.

Post by Cheromaniac »

Using 5th gear (NV3550 transmission I presume) with 33" tires definitely wouldn't have helped the dyno numbers! They should have used 4th.
Stock 4.0 engined Jeeps like yours typically put down about 135rwhp so if we assume a 29% drivetrain loss, yours would be making about 240hp & 310lbft at the crank. That's on par for a mild stroker.
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