Muad'Dib 4.7L stroker build

[cruiser54]

Working with someone who has a 4.6 Renix stroker.

Pings on hot days. ST is 79 to 91 and LT is 119 when warmed up.

timing is showing 14 to 15*. I've never observed higher than 12* when scanning a Renix.

Have you seen higher timing numbers?
What do you think of the fuel trims.

26# injectors

[Muad'Dib]

LT doesn't change on my MT2500 so I cant really speak to that, but ST seems too Rich (lower than 128; higher is lean). You want it to be as close to the median (1-256 is the range so 128 is median) as possible. IM the oddity that needs smaller injectors.. but most seem to get by with 24#. 26# would seem way too big to me and it seems to show in the STFT.

I haven't paid enough attention to my timing but I will take a look at mine with my 229AC and let you know what It reads at idle. The cam was installed straight up.

[CrankyD]

Now that you have had the motor running for a while how do you feel about your cam choice? I am building a 4.6 and I am concerned about not having enough off idle power and not being able to pull from extreme low RPM's. My other choice would be a stock 4.0 1995 cam or the Mopar 4529228ad. Thanks for the good documentation and follow ups.

[Muad'Dib]

Now that you have had the motor running for a while how do you feel about your cam choice? I am building a 4.6 and I am concerned about not having enough off idle power and not being able to pull from extreme low RPM's. My other choice would be a stock 4.0 1995 cam or the Mopar 4529228ad. Thanks for the good documentation and follow ups.

Super sorry for the delay. I find myself checking this website less and less... its quite sad on my part

Anyway to answer your question, I am very happy with my cam choice. Its amazing how much torque I seem to have.. although I have yet to Dyno the thing. I haven't had any cam issues and im running synthetic now too.

I am a speed demon though, so if I were to play with any configuration I would go with a more aggressive cam to give me higher RPM power. When shifting from 2nd to 3rd at WOT it tend to be between 4000 and 5000 RPM's for what seems like a long ass time (im sure its not that long). Id rather bang through that range and shift to 3rd pulling even more.

In summary seat of the pants power is pretty awesome. With certain ground conditions its very easy to break loose the rear end. Most cases though it throws you back and shoves off quickly. I have a larger throttle body too so that helps with the throttle response.

[NickInTimeFilms]

Hey man, I've read over the tail end of your build and it looks like we're in the same boat. 24# Injectors are just too much for my Renix 4.6L. ECU goes into closed loop and Short Term Fuel slowly drops to 0 then the computer gives up and runs it rich at 128. Stock injectors are running 106-120 ST fuel so it's actually metering now. I'll try those 19# Injectors you suggest and see If they don't help me as well. Thanks for the Tip, who woulda thunk?

[cruiser54]

I've got the 24# injectors in mine on the engine stand. Renix system on an HO Golen stroker.

Start there and see how it works?

[NickInTimeFilms]

Try em since you got em I guess. If you have a scan tool to hook up then you can see how the ecu adjusts the fuel trims. I tried 24# and it was huffing so much carbon monoxide I Damn near passed out. 22# 94xj injectors were also too big. The stock 19.6# seem to do well enough. I may get a wide band o2 just to make sure it's not running lean on the top end. An exhaust gas analysis will tell you what's going on down stream as well.

[cruiser54]

I have a DRB with the Renix adapter and cartridge.

[Muad'Dib]

I use my MT2500 and my Wideband for checking on mine... its nice to hear that I am not a complete lone ranger that needs smaller injectors.. HAHA

[NickInTimeFilms]

Find out anything useful on your wideband setup for tuning purposes? I got those 19.4lb/hr 712 Injector you suggested, works great. You wouldn't believe the carbon buildup on my pistons after 500 miles, looks like a chimney sweeper after a long day. Passed inspection with stocks injectors with flying colors.

[Muad'Dib]

I primary use the Wideband for validating that I'm running in the right AFR range during all the conditions that the Jeep goes through. If I see its off then I know "something" needs to be tweaked. Fuel pressure, failed TPS etc. I don't do any major tuning though.

[marcusofmagna]

So how did this build work out for you? Im building a 4.6, blocks in the shop being decked to .005, 0 just scares me. Scat crank, scat forged rods, KB 945's 630 P&P head, Y&T roller rockers etc... Looking forward to getting it done but a lot of stuff to consider!!!!

[Russ Pottenger]

So how did this build work out for you? Im building a 4.6, blocks in the shop being decked to .005, 0 just scares me. Scat crank, scat forged rods, KB 945's 630 P&P head, Y&T roller rockers etc... Looking forward to getting it done but a lot of stuff to consider!!!!

Marcus,

Hopefully you double checked and ran the numbers on your static compression ratio on your build.

If your coming up with anything close to a stock 58ish cylinder head combustion chamber volume you're going to wind up somewhere around a 10.5:1 static compression ratio

Russ

[marcusofmagna]

I,m new to strokers but not mechanics. As for the static ratio you are correct, the dynamic at the altitude I live is around 8.3:1 so pretty good but not monsterous.

[marcusofmagna]

I am extremely curious about the need, or should I say advantages of upping my TB diameter to maybe 65, or 68mm, and going to the 99 plus intake.
Any thoughts on this?