Muad'Dib 4.7L stroker build

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Re: Muad'Dib 4.7L stroker build

Post by SilverXJ »

My opinion on people spinning tires, even with the stock 4.0L, is that they are running crappy tires with little traction. With the stock 4.0L I could spin the stock tires. After I got rid of the stock tires I could not. Same size, just a stickier tire. Same thing in the rain. Stock tire was a nightmare pulling away from a light.. needed 4 full time to stop the slipping. Good paid of tires and the full time is there just for extra confidence and the slippery spots.
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Re: Muad'Dib 4.7L stroker build

Post by IH 392 »

Muad'Dib wrote:Still feeling a little let down and feel like maybe cam choice is ok.. I was shooting for around 275...
My desktop dyno simulation with that cam shows a "guesstamation" of only 222hp @ 4000rpms and 336ftlbs of torque @ 2000rpms.
You can get more power out of ANY engine!!!
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

Well crap.. maybe the power im "not" feeling IS because of cam choice.....
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

What would you guys recommend to get a little more power out of what i currently have?

I need to upgrade the whole exhaust system to a 2.5" mandrel bent set-up thats for sure...

Maybe advance cam?

Match Intake manifold to Head like i should have done but didnt?

Im at a loss.

This was my first performance build ive ever done let alone a "real" engine rebuild. And although the power output and money put down has kind of put a bad taste in my mouth im trying to focus on the positive and realise that i did it mostly myself (with the help of you guys of course) and i did it the way i wanted to do it. I have to be happy for that if not for anything else. And for all i know my butt dyno is out of tune and im making more power than i think.. just at a dead stop trying a couple WOT runs.. im getting no wheel spin with bald tires. Now if i take it around a turn and slam the throttle thats another story altogether... but i could do that with the 4.0 too.
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Re: Muad'Dib 4.7L stroker build

Post by shawnxj »

what cam did you end up with? i don't see it on your parts list on the first page. only thing i could suggest is a bigger cam but your not gonna gain that much more power. the lunati 63501 i chose comes out on my desktop dyno at 266hp@4500 rpm and 363tq@2500 rpm and that's a fairly big cam. there are bigger but i was hoping to keep some gas mileage and still have the power i want. after i get this built if it turns out i'm disappointed in it i'll sell it and swap in an ls. woulda been a $1000 cheaper for me to do the ls in the first place and my build is only running me about $2500 so far. still need to deck the block, rebuild the head and buy a timing chain and pushrods but otherwise everything else is sitting in my kitchen
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

My cam is in the first post... its the Mopar P4529229AC.

Found out a few things today:

1.) With the AC off you make more power lol ;)

2.) have some renewed faith in my stroker today. I don't know what changed, or if it has broken in more and is sealing up nicely, but today its been feeling a little more torquey. At a complete stop, WOT = massive burn out. Maybe with all my shit talking, my Jeep decided to show me up. I don't know what could have changed with it other than sealing up nicely. If it seals up more i will be way more than impressed because with the change today it was a huge performance increase.

3.) Doing WOT runs, i'm running rich at around 10.5-11... usually around 11. Not sure how to cure that yet.

Two future plans..

1.) 2.5" mandrel bent exhaust system.

2.) Fix intake "tubing" into Throttle Body. Its pretty restrictive with the stock 91-?? rubber tubing.
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Re: Muad'Dib 4.7L stroker build

Post by seanyb505 »

Regearing will give you a huge off the line boost but will slightly lower your fuel economy. Do you have an auto or manual? If you have a manual it's as simple as grabbing the rear axle from any auto XJ. That is if you haven't gone to larger tires and regeared yet anyway.

Regarding Valvoline VR-1: is the off the shelf stuff any good or do you have to get the formula that the chain stores don't sell?
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

seanyb505 wrote:Regearing will give you a huge off the line boost but will slightly lower your fuel economy. Do you have an auto or manual? If you have a manual it's as simple as grabbing the rear axle from any auto XJ. That is if you haven't gone to larger tires and regeared yet anyway.
I have the AW4, but im stock all the way around so re-gearing is nowhere but in the future and would really be pointless right now with stock tire size. My 3.55's are perfect. I do have a Dana44 waiting to be regeared in my storage so thats a future to do when i move away from modding the engine.
seanyb505 wrote:Regarding Valvoline VR-1: is the off the shelf stuff any good or do you have to get the formula that the chain stores don't sell?
Its my understanding that its all the same. Only one place in town had the 10w30.. however multiple places had straight weight or 15w+.
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

This weekend i built and installed an adjustable MAP sensor. My goal is to lean her out a bit at WOT. Was running down to 11 when @ WOT, and i want to get it up to 12.7ish. My factory MAP voltage is 5.06v. I adjusted my adjustable to 4.5v

This morning was the first time i actually drove it much with the adjustable MAP, and i tell you what the engine didnt like that at all. It took longer to crank over and start, and it ran a bit more lean then usual. I let her warm up a bit till everything settled in, and when i left for work, the engine felt sluggish. AFR shows 14.7 - 15ish. Im sure i need to up the voltage .. however i havent done a WOT run yet.

Anyway, what is everyone doing about cold starts with an adjustable MAP? Are you running stock until warm, then switching over to Adj MAP, or is my voltage really that far off?

Ill be able to test more this week, but figured i would post up ;)

Thanks!
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Re: Muad'Dib 4.7L stroker build

Post by gradon »

Cold starts should be in the 13:1 range. If you went too low on the voltage, you'd see >15:1. Try 4.75V
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Re: Muad'Dib 4.7L stroker build

Post by SilverXJ »

The PCM may also take a bit to relearn the new voltage.
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

Well i tried 4.75 and it didnt lean me out enough.

I also noticed that when i adjusted my TPS i set it to 4.2v when from what i can tell its suppose to be 80% of the input. Well my input is only 4.71v so i set it to 3.77v and am giving that a try.

I played around ALOT with the MAP voltage today, and im down to 4.45v. This gets me just slightly over/to 12. I could probably drop it down to 4.4v and get up to 12.5 AFR.

Im keeping it at 4.45 and im going to see how it starts in the morning and all that.

Butt dyno doesnt really notice a difference... but i can definetly hear a difference. I cant describe the sound difference, but its there.

Otherwise besides trying to tune AFR, Engine runs well. I can feel it kind of give out in second gear at 4500rpms (CAM?). The RENIX shifts at like 4900 or 5000. It pulls to 4500 then it seems like it moves/hangs through 4500 to 5000 SLOWLY before i shift to 3rd and then i pull ahead again and run through 75 quickly.

Im thinking of getting a High Altitude CPS since i am at high altitude and i need a new one cause the wires are burnt from the old exhaust.
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Re: Muad'Dib 4.7L stroker build

Post by gradon »

What are the AFRs b/t 4500-5000? If fuel is there, maybe the cam isn't providing enough air. What valve springs did you use(I'd expect this result from people who used stock springs on cams with bigger than stock lifts)? What TB are you using(hopefully at least a 60mm)? Renixes HP peaked at 4500, but should still have 90+% up to redline(enough to pull it through).
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

gradon wrote:What are the AFRs b/t 4500-5000? If fuel is there, maybe the cam isn't providing enough air. What valve springs did you use(I'd expect this result from people who used stock springs on cams with bigger than stock lifts)? What TB are you using(hopefully at least a 60mm)? Renixes HP peaked at 4500, but should still have 90+% up to redline(enough to pull it through).
All my parts are in the first post...

229AC Mopar cam with stock (Recommended) valve springs that are brand new. 68mm Dodge Dakota TB. AFR is 12ish right now with the adj MAP all the way through the RPM range. Mind you im watching RPM's... im still making the speedometer climb nicely... but as stated between 4500 to 5000 in 2nd it seems to stop climbing so hard. I am worried about the air intake not allowing enough air flow though. im temporarily using the stock 91+ rubber peice that sits inside a 3.25" coupler. I am in the process of mocking up a better way to do it and still clear the hood.


This morning, i started the Jeep up and it only stumbled for like 1 second then caught itself and idled normally. AFR started out at 11.something and climbed to 12ish within 5 seconds. Stayed there for a few seconds, and then slowly climbed to 14.7 and kinda rocked back and forth between 14.5 and 15.5 during warm up. When i left for work i didnt feel the hesitation i did the prior day, so im thinking SilverXJ might be right. When i originally set the MAP voltage to 4.5v, i didnt get a chance to drive it... so the next day im sure the computer didnt like that. Since i drove a lot yesterday it kinda "learned" that it was going to get a lower MAP voltage and was prepared for that the next morning. Im currently at 4.45v, and i think im going to drop it down a tad more to 4.4v.

On my TPS, i need to adjust it again today.. i set it to 80% and again i was wrong.. it should be 83% which should bump it back up to 3.91v.
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Re: Muad'Dib 4.7L stroker build

Post by Muad'Dib »

Set TPS to 3.92v and have the Adj MAP down to 4.35v Now at WOT im right around 12.5 and im not going any lower on the MAP just to try and lean it up to 12.7ish... I feel kinda sketchy as it is about it. Im going to leave it there for awhile and see how i feel in a couple weeks.
If it feels right, then STROKE it!
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