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New to Jeep world and modding them

9K views 61 replies 15 participants last post by  Passmg2 
#1 ·
I am in the market for a 12-15 SRT GC and have several questions and any help would be appreciated. I have been in the diesel racing side of things my whole life and want something new and different.

1. What is the weakest part of these jeeps when adding horsepower that usually break first?

2. How much horsepower can stock internals and transmission hold reliably with the occasional sprint to 130 on an entrance ramp etc?

3. How lenient are the dealerships about voiding warranties?

4. Any big differences in engines or materials used from 12-15? For example on my truck they changed the internals a few times and still same engine and same body style they called them job 1, job 2 and job 3. and job 3 were stronger than the previous, so basically just asking if jeeps have anything like that or are they all the same?


I apologize for my lack of knowledge in this field but I really appreciate any help in advance!

Just trying to do my research before I buy and build!


Thanks!
 
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#2 ·
1. Forced induction supposedly. Can't boost them safely (depending on what that means to you) without internals.

2. They are a bit of a wildcard but anything over mid-500's crank seems to be iffy.

3. Totally depends on the service writers.

4. Don't know the previous motors but the 6.1s appear to be built a bit more stoutly when it comes to FI.
 
#5 ·
Awesome. Thanks for the help. I will give demon a call

So a tune, CAI and exhaust wouldn't be putting anything under too much stress?

What hp #s would that get me to

if i put a blower on it would the only thing really needing to be replaced is the crank?

Thanks for all the help!
 
#8 ·
I would save the money on the exhaust & run 6 psi with a conservative Jersey Boy or Johan tune and you'd get 525-550 awhp easy. If you want it louder remove the resonators. If you're going to beat on it / high boost / crappy tune / crappy kit then you'd need to replace rods & pistons with forged - not the crank - it's already forged. IMO as I'm a self-proclaimed expert... :silly:
 
#9 ·
Dont like coffee so thats good to know!

Looks like Ill do exhaust and procharge it with a lite tune and then from there get things forged one by one until I can get a more aggressive tune.

With having that 525-550 what times could I be seeing and how hard could that be driven before it starts to have problems?

Thanks guys really appreciate the help
 
#10 ·
I recommend as others have talking to Skip at Demon Performance. He will look after you and be totally honest. They did mine. You can see the numbers in my signature. 600-650 would be max all wheel horsepower on cast pistons & rods but ask Skip. All I have is their D-1SC kit / 3.5" pulley and Kooks headers / Kooks full exhaust and Johan tune. Seriously, the exhaust probably doesn't add that much but does help air flow & I would imagine combustion chamber temperatures. 525-550 awhp should be 11s. From what Demon Performance has told me you won't have any problems until you start sensing knock during data logging. But it is definitely worth a call to Skip!! I would love to see one of their kits on a WK2 with nothing else and see what it does. The 4-5k for a full exhaust or whatever it was will probably net you 30 - 35 hp although I'm talking out my a*s again. Just going by what I've heard. Contact me if you want to ask more questions and good luck bud!
 
#21 ·
I lost ringlands at 6.5psi and I thought I was safe. I have a forged motor now. I don't know what to tell you. You see everyone say on here that these 6.4s don't like boost with cast pistons. I would have to say forged for peace of mind. If I did it again with a stock motor I would do meth kit and custom tune.
 
#22 ·
Meth is the way to go! I was at 10psi with my 6.1 and never had any issues. I know the ringlands on the 6.1s are bad as well. That being said my tune was not tuned with the meth on. We tuned with it off and then i added the meth for an extra buffer. It still added another 20 at the wheels without being tuned for it. Oh and the intake temps were so nice :)

I am actually debating on grabbing an afe intake and meth kit for this one just to keep the temps down...
 
#23 ·
Here is the times for bolt ons vs stock.... '12

stock...best 1/4 13.1
AFE intake 13.1...no difference expect for sound
AFE intake plus AFE cat back...... stock tune 13.3, 91 oct diablo tune 13.1..... (pissedoff.com!!!)
Bolt ons...waste of time unless you want to sound better and go slower.

If you want to get faster get a blower and be done. Low PSI till you can build your motor. I am saying f**k it now and will soon pull my motor and trans out, build and come back with 1000hp. I will go twin turn go. Much easier on all parts. Balls out or go home for me
 
#24 ·
I said afe for thes simple fact you can drill it for meth and i dont want to tap my stock intake. If your expecting gains from intake and exhaust its been proven minimal at best. currently im running 4.3/12.9 stock. I would just like to get the intake temps down and consistent. Meth is a very simple way to go about it. And with a controller switch changes over to boosted applications very easy.

I took the gamble on a blower on my 6.1 without building the bottom end and I swear the meth saved me. Even if I chose to go built/boosted with the 6.4 meth will be on it.
 
#26 ·
To be honest bud (dub spelled backwards lol, not sure the significance) but I don't think it's easily found where I am and at 15-20 mpg now and 1/4 of my tank rendered useless by twin 405s I would be concerned that I would need a greater volume of fuel. Is this not the case with e85? Thanks man.
 
#27 ·
You're correct in volume but not via larger tank, rather bigger hoses from tank to fuel rail.

For example the n54 engine in my e92 335i requires a lpfp aftermarket, & either PI (port injection) or TBI (throttle body injection) to run full e85 100% of the time.
As I only have a stage 2 lpfp I only run an e60 tune on my 335i.

HOWEVER: the N54 in the z35i bmw convertible can run full e85 all day as it has beefier fuel lines, a more stout factory lpfp, and I believe a better hpfp. SO that car needs nothing but a tune to take advantage of full e85.

I am shocked no one is running e85 or a blend of it on these rigs cause you guys have heat issues as it is with IAT's in the summer like we do on the BMW forums. We supplement this with a better FMIC but also with e85 as well :)
 
#28 · (Edited)
I have a Demon Performance Fore twin Walbro 405 fuel pump return fuel system. Will that handle e85, I don't know. I was concerned with the greater volume of fuel I would burn through shortening the range of my Jeep on a tank of fuel. It's something I haven't researched as I'm happy with the performance and IATs are much lower with the scoop. Also, I have a Snow, Stage 2 Boost kit half installed.

Edit: Here's the fuel system I really have and not the one I thought I had and lied about above. I checked with Skip. It's a Demon Performance spec'd Fore return style fuel system, AEM 1200 primary pump and TI 465 secondary pump and stainless steel lines. Like Tim said, Skip said I'm good for ethanol...woohoo!
 
#33 · (Edited)
Unless he was using cheap summit steel braided rubber hose any decent fuel line will be e85 compatible. I always suggest running PTFE lines or hard lines.

E85 has a lot of misconceptions surrounding it. To say it eats fuel lines and pumps is a broad and incorrect generalization. Running e85 is fine if you have the pumps, injectors and tune to support it.


Sent from my iPhone using Tapatalk
 
#38 ·
I have a fuel gauge under the hood that reads 63psi at idle. I have not figured out a way to look under there while bombing down the road. I have an Innovate dual Wideband to register air / fuel ratios which I monitor with my Trinity. If I didn't say that right then, by all means, someone smart please correct my lingo. Thanks.
 
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