Jeep TJ SRT4 build

crice

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Jun 30, 2021
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Alright I’m ready to lose my mind reading threads that never get answered lol. I’m going to be turboing my 04 SE 2.4 after I found it it’s the same motor in the Neon SRT4. This will be somewhat of a build thread and somewhat of a question thread. I’ve already bought a exhaust and intake manifold, injectors and fuel enrichment piggyback system. I’m also going to do a rebuild on the motor with HOPEFULLY SRT4 internals(hoping someone can answer if that’s doable or been done?). Also plan to put in a nv3550 tranny(does anyone rebuild these to handle more than the rated 300ft/lbs?) not long after I do the motor work, and possibly Dana 44s if I can find them or atleast a super 35. So here’s my Jeep Brad in all his glory, and here’s to a college kid staying broke because of him :)

image.jpg
 
looking good! waiting to see how this turns out!
Thank you! Also forgot to add I’d like to tune the pcm to run E85 by someone who’s good with Neon SRT4s, would like a 87 tune as well if possible, not sure if that’s doable to have 2 tunes on a stock pcm
 
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There is a thread over on JF where someone swapped a SRT4 into his TJ and it ended up taking more than he originally thought but it is running. I'll see if I can find the thread and put a link here for you.

Edit: Here ya go. Hope this might help you some with this project.

https://tinyurl.com/brx7xp5
 
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There is a thread over on JF where someone swapped a SRT4 into his TJ and it ended up taking more than he originally thought but it is running. I'll see if I can find the thread and put a link here for you.

Edit: Here ya go. Hope this might help you some with this project.

https://tinyurl.com/brx7xp5
Yes I’ve seen that infamous video of him smoking the mustang lol. A few key differences for me are that I want to stay manual, keep my pcm, and rebuild my block rather than dropping in a whole other one, I can get a full SRT4 rebuild kit for about $500 so that’s probably what I’ll end up going with.
 
Thank you! Also forgot to add I’d like to tune the pcm to run E85 by someone who’s good with Neon SRT4s, would like a 87 tune as well if possible, not sure if that’s doable to have 2 tunes on a stock pcm
You can tune for different fuel grades. You will need to get a harness that has the ability to work with flexfuel sensor. The sensor will detect which fuel it is getting and make the adjustments as needed.

MightyCarMods on Youtube does this all the time on their builds so they can run E85 or other available gas grades.

EDIT - If you are indeed wanting an E85 tune, then you may need to ditch the factory PCM and use an aftermarket ECU made for the Neon SRT4, that way it is somewhat plug and play.
 
Yes I’ve seen that infamous video of him smoking the mustang lol. A few key differences for me are that I want to stay manual, keep my pcm, and rebuild my block rather than dropping in a whole other one, I can get a full SRT4 rebuild kit for about $500 so that’s probably what I’ll end up going with.

Well I haven't read thru his whole build thread so didn't know if it could help any or not.

For tuning your PCM I'd talk to Flyin Ryan Performance and he's also a member on here.
 
The stock PCM can only store one tune at a time. If you want a tune for each you will have to flash it back and forth. Problem becomes if you have a few gallons of 93 left in the tank and top it with E85 you may end up with E65 or something like that. Also depending on where you live they sometimes blend ethanol differently depending on the time of year. I have tested everything from E90 to E60 from the pump. It's also worth noting that ethanol doesn't play well with some fuel tanks. I have seen some tanks primarily the ones with PVC liners start to degrade with ethanol.
What piggyback are you planning on running?
What injectors do you have?
An 87 octane tune is doable if you keep lower compression and have boost control with a low base setting.
I remember when you could buy the SRT-4 piston and rod combo for $13 a piece and get an entire ring set for $11. That was from Dodge back when the SRT-4 was new. You could build a 500hp engine for $500.
I have the 3550 and am running right at 300 ft/lb with no issues. I did spike 500 ft/lb and broke the transfer case output shaft. I wouldn't plan on running more than 3-400ft/lb without upgrading the transmission and transfer case.
 
You can tune for different fuel grades. You will need to get a harness that has the ability to work with flexfuel sensor. The sensor will detect which fuel it is getting and make the adjustments as needed.

MightyCarMods on Youtube does this all the time on their builds so they can run E85 or other available gas grades.

EDIT - If you are indeed wanting an E85 tune, then you may need to ditch the factory PCM and use an aftermarket ECU made for the Neon SRT4, that way it is somewhat plug and play.
I’ve heard we can tune our stock pcm from a few different people, is that not doable if I want to run e85 vs 87 or 93?
 
I’ve heard we can tune our stock pcm from a few different people, is that not doable if I want to run e85 vs 87 or 93?

Yes you can by contacting a company like FRP who offers customs tunes. You'd need to contact him about if he can do tunes for e85. For different octanes yes he can make you tunes for that.
 
The stock PCM can only store one tune at a time. If you want a tune for each you will have to flash it back and forth. Problem becomes if you have a few gallons of 93 left in the tank and top it with E85 you may end up with E65 or something like that. Also depending on where you live they sometimes blend ethanol differently depending on the time of year. I have tested everything from E90 to E60 from the pump. It's also worth noting that ethanol doesn't play well with some fuel tanks. I have seen some tanks primarily the ones with PVC liners start to degrade with ethanol.
What piggyback are you planning on running?
What injectors do you have?
An 87 octane tune is doable if you keep lower compression and have boost control with a low base setting.
I remember when you could buy the SRT-4 piston and rod combo for $13 a piece and get an entire ring set for $11. That was from Dodge back when the SRT-4 was new. You could build a 500hp engine for $500.
I have the 3550 and am running right at 300 ft/lb with no issues. I did spike 500 ft/lb and broke the transfer case output shaft. I wouldn't plan on running more than 3-400ft/lb without upgrading the transmission and transfer case.
I’ll be putting in Bosch 750cc injectors while I run 87, I’ve heard I’m going to need 1000cc if I want to run e85 so might have to upgrade? and I’ll be putting in either 8.0 or 8.5 compression pistons when I do the rebuild, I’m using a split second fuel enricher. It’ll def be low boost for now to try to prevent detonation since I can’t retard timing without a tune. When I get it tuned I’m hoping for maybe 300-350ft lbs

https://splitsec.com/product/lsc1-001-universal-fuel-enrichment-module
 
I’ll be putting in Bosch 750cc injectors while I run 87, I’ve heard I’m going to need 1000cc if I want to run e85 so might have to upgrade? and I’ll be putting in either 8.0 or 8.5 compression pistons when I do the rebuild, I’m using a split second fuel enricher. It’ll def be low boost for now to try to prevent detonation since I can’t retard timing without a tune. When I get it tuned I’m hoping for maybe 300-350ft lbs

https://splitsec.com/product/lsc1-001-universal-fuel-enrichment-module

Many people are going away from SplitSecond stuff with the better available tuneability now offered for Jeep PCM's.
I'd contact a company that does tunes before i bought anything and see what they can and can't do plus what they recommend.

Have you looked at the 2 other current active turbo threads going on right now? While not the 2.4 there is still a lot of good information in them.
 
Many people are going away from SplitSecond stuff with the better available tuneability now offered for Jeep PCM's.
I'd contact a company that does tunes before i bought anything and see what they can and can't do plus what they recommend.

Have you looked at the 2 other current active turbo threads going on right now? While not the 2.4 there is still a lot of good information in them.
I haven’t I’ll have to do that, I already bought the enricher but maybe I’ll contact some places around me and see what it’ll run me
 
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I haven’t I’ll have to do that, I already bought the enricher but maybe I’ll contact some places around me and see what it’ll run me

Ryan from Flyin Ryan Performance is very knowledgeable and has great customer service from all I've heard. 10-15 years ago SplitSecond was the go to place for forced induction on our rigs since at that time no one really dappled in Mopar/Jeep/Dodge PCM's and especially the Jeep PCM. But now that they have been messing with the PSM's and able to do some better tuning I seem to see a lot more people who have taken the splitsecond stuff off and gone with a custom tune.
 
Ryan from Flyin Ryan Performance is very knowledgeable and has great customer service from all I've heard. 10-15 years ago SplitSecond was the go to place for forced induction on our rigs since at that time no one really dappled in Mopar/Jeep/Dodge PCM's and especially the Jeep PCM. But now that they have been messing with the PSM's and able to do some better tuning I seem to see a lot more people who have taken the splitsecond stuff off and gone with a custom tune.
Yes that will inevitably be the goal to get a custom tune, the $200 enricher is a better option than a $600 tune for me now atleast
 
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This is my thread but I got a new account lol. A lack of funds and time has made me put this off for a while, but we’re back at it soon. And some plans have changed! We’re going to pick up an srt4 motor Saturday
 
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