Charger Forums banner
1 - 20 of 21 Posts

·
Registered
Joined
·
379 Posts
Discussion Starter · #1 ·
Just stopped by the local performance shop after seeing a black 2006 SRT sitting out front. Questioned the fellow about his dyno and installing mods, tunes, etc.. We walked out and he popped the hood on the SRT and there it sat. SWEET! He said it was putting out 486 at the wheels. Not sure if that is great or not? Sure looked good though. The intake turned down right behind the drivers side headlight and had the intercooler tucked up nicely behind the grill.
 

·
Registered
Joined
·
2,320 Posts
Yeah, 486 at the wheels aint too shabby at all, and thats about what to expect from your avergae SRT-supercharged vehicle. Hes probably at somewhere in the vicinity of 525-550 crank hp, so its where it should be. Paxton has had a supercharger out for some time now that seems to be working pretty well with the SRTs.

-Pat
 

·
Registered
Joined
·
23 Posts
They run good, but they don't run long. Hemi's don't take to forced air too well. BUT THEY LOVE CAMS !!!!!
 

·
Registered
Joined
·
488 Posts
Maybe the 5.7's dont ...but the SRT's are built stronger, just can't run too much boost on a stock bottom end.
 

·
Registered
Joined
·
144 Posts
Now when you say something like what DMR said about the HEMI not taking very well to forced air induction I have to ask the question. What objective, documented evidence can you give to back that statement up?

If you have it, just post it to the thread so I can see what my HEMI has in store for me. If you can't post the evidence because it is written somewhere, popint me to the document so I can go look for myself.

Oh! And any evidence that is based on he said or she said that cannot be backed up by real data is not credible in my mind.

I would appreciate it if we could nip this in the bud as Barney Fife use to say.
 

·
Premium Member
Joined
·
5,466 Posts
Under search, there are several threads and owners on the GSmotorsport SC that dumped the bottom end. About 6psi is the max for the 5.7. do the search on this, there are the answers. It's the tuning that kills them, the Predator is suppose to help solve this problem, with a good tuning guy doing it.
 

·
Registered
Joined
·
676 Posts
I'm sure that there are a few vendors on here that would claim that the Hemi is more than capable of handling 6-8 pounds of boost reliably, as long as you upgrade the proper parts and go with the proper tune to support the turbo/supercharger/NOS.
 

·
Registered
Joined
·
6,081 Posts
Under search, there are several threads and owners on the GSmotorsport SC that dumped the bottom end. About 6psi is the max for the 5.7. do the search on this, there are the answers. It's the tuning that kills them, the Predator is suppose to help solve this problem, with a good tuning guy doing it.
It's also GSM's silly fueling strategy (supplemental injectors in the intake instead of just replacing the stock injectors. That said, I don't think I would feel comfortable with more than 6psi without beefing up the bottom end regardless of which SC kit was used.

Best,
 

·
Registered
Joined
·
90 Posts
Well I'll be the first to say GSM is a bunch of tards that rapes people blind, but he's right about 5.7 motors. KRC has had problems as well with their project rams and hemi's. Also, SouthEast performance has had problems with their test kits. The problem is the more on the top end than lower end. the pushrods and valve springs are very weak. Sure, those can be changed, but I believe their were more internals as well that couldn't handle the boost right. Even ATI had problems, thats why it took over a year in testing. As it stands, a factory untouched 5.7 hemi can only handle 6PSi before things go BOOM. Its been tested by all the SC companies and shops. But don't take my word for it, call ATI up, or Vortech, or Paxton...I'm sure you'll get the same response.
 

·
Registered
Joined
·
175 Posts
The factory rods rods and pistons are powder metal and are only good for about 500 crank horse power before they give up the ghost; on 5.7s the crank is powder metal and also only good for about 500 hp. 6.1s have a forged crank shaft that should be good for 6-700 crank hp. The other big limiting factor is compression ratio more then 5 or 6 lbs of boost and detenation starts to become a real issue. My advice if you plan on building boost invest in a new bottom end and have the cumbustion chambers on the heads opened up a little to drop the compression ratio down to about 9 to 1 first, and if its a 5.7 get flat top pistons.
 

·
Registered
Joined
·
10,177 Posts
Yeah, it seems like 6 PSI is about the max without building a new bottom end.

So far, these cars have not proven to be good cars for modding no matter which model. Sure, you can do it. But to get large performance gains you are talking tens of thousands of dollars.
 

·
Registered
Joined
·
676 Posts
If you want to boost.....forge the bottom end and drop the compression ratio. It's the same formula for any engine. Lower compression allows for more boost. Easiest way to lower it would be to either put a spacer between the block and heads or decrease the stroke of your crankshaft. Also, could just order lower compression pistons too. Many solutions to the same problem....but they all cost a pretty good chunk of change :(
 

·
Registered
Joined
·
90 Posts
If you want to boost.....forge the bottom end and drop the compression ratio. It's the same formula for any engine. Lower compression allows for more boost. Easiest way to lower it would be to either put a spacer between the block and heads or decrease the stroke of your crankshaft. Also, could just order lower compression pistons too. Many solutions to the same problem....but they all cost a pretty good chunk of change :(
Thats if you want serious crazy boost. ATI makes a intercooled 6PSi kit, which will net more gains than the competitors.
 

·
Registered
Joined
·
676 Posts
Thats if you want serious crazy boost. ATI makes a intercooled 6PSi kit, which will net more gains than the competitors.
I know that ATI makes a pretty nice kit. I posted a thread stating that the 5.7 kits were coming out soon. The 6.1 kits are still in the works though and absolutely no supercharger will net you as much gains as a turbo will. It's just that it takes less power to spin an impeller using free exhuast gasses rather than using fuel and power to turn a belt driven impeller. Also, that isn't just for "serious crazy boost", that's for anyone who doesn't want to have to worry about putting a hole in their pistons once the carbon builds up and increases your compression ratio. It's better to spend the money and make something stronger than it needs to be imho, that way you don't have to worry half as much about it :wink:
 

·
Registered
Joined
·
65 Posts
Yeah, it seems like 6 PSI is about the max without building a new bottom end.

So far, these cars have not proven to be good cars for modding no matter which model. Sure, you can do it. But to get large performance gains you are talking tens of thousands of dollars.
You have to remember as well, the Hemi engine is still a new platform by engine standards. Look at how long it took for the 4.6L fords to get a good aftermarket following. The 4.6 had been in production steadily since 93 and only within the last three to four years have really come up to speed on aftermarket coverage, around a decade on the road. GMs are lucky in the fact that their aftermarket is huge and almost immediately have goodies available.

Mopars have also been traditionally based around Mopar Performance Parts, a select few aftermarket companies, and some guys that knew how to Voodoo the cars very well. They have never really had the aftermarket following of the GMs or Fords.

It'll come, it just takes time and money
 

·
Registered
Joined
·
184 Posts
Yeah, it seems like 6 PSI is about the max without building a new bottom end.

So far, these cars have not proven to be good cars for modding no matter which model. Sure, you can do it. But to get large performance gains you are talking tens of thousands of dollars.
That's odd, my turbocharged 300C with an all stock internals 5.7 has over 24,000 miles on it with the turbocharger. It seems to be quite happy running between 8-9 psi.

As I have said many times, the trick is keeping the AFR's and the EGT's both in check. My EGT's under full boost never run more than 50 degrees above the max I have seen on stock engines, and in low boost (5-6 part throttle) AFR's flat line between 11.9 - 12.9 (higher the boost the lower the AFR number) and in full boost they run 11.5 - 12.5 (11.5 at 9psi).

I have never had any mechanical problems with the drivetrain, and still run the stock plugs. I find that very few people ever monitor their EGT's, and that is just as critical as watching your AFR's.

Mr MoPar
 

·
Registered
Joined
·
184 Posts
If you want to boost.....forge the bottom end and drop the compression ratio. It's the same formula for any engine. Lower compression allows for more boost. Easiest way to lower it would be to either put a spacer between the block and heads or decrease the stroke of your crankshaft. Also, could just order lower compression pistons too. Many solutions to the same problem....but they all cost a pretty good chunk of change :(
Dropping the compression ratio is primarily done in response to elevated cylinder temps and/or a hot intake charge. If you drop your compression one point, that equals nearly 3.5 psi boost.

Higher compression ratio will net more HP for the same boost level as long as you can keep the EGT's in check. A cool dense intake charge coupled with water/methanol injection does wonders on higher compression engines.

On the dyno in 90+ degree air temps, my intake temps peaked at 140 degrees, I have seen those temps on a stock engine. My IAT is upstream of the injection point, so my intake temps are running 50 - 70 degrees cooler than the IAT sensor sees.

Mr MoPar
 

·
Registered
Joined
·
720 Posts
That's odd, my turbocharged 300C with an all stock internals 5.7 has over 24,000 miles on it with the turbocharger. It seems to be quite happy running between 8-9 psi.

As I have said many times, the trick is keeping the AFR's and the EGT's both in check. My EGT's under full boost never run more than 50 degrees above the max I have seen on stock engines, and in low boost (5-6 part throttle) AFR's flat line between 11.9 - 12.9 (higher the boost the lower the AFR number) and in full boost they run 11.5 - 12.5 (11.5 at 9psi).

I have never had any mechanical problems with the drivetrain, and still run the stock plugs. I find that very few people ever monitor their EGT's, and that is just as critical as watching your AFR's.

Mr MoPar
I'd like to know mroe about this turbo u have.........production kit yet?
 

·
Registered
Joined
·
184 Posts
I'd like to know mroe about this turbo u have.........production kit yet?
Yes it is in production. System designed and produced by Creative Induction Systems (CIS) and available through Power Ported Performance for both 5.7 and 6.1 engines.

A couple weeks ago, I ran a 12.95 @ 109.77 with a crappy 2.2+ 60ft time. This was on a 2006 300C with an all stock 5.7 (factory cats and sparkplugs) with just the bolt on turbo system. Car was at full street weight (nothing removed) had 3/4 of a tank of fuel, a 12" sub and amp in the trunk (including the spare tire), running 20" rims with the SRT RSA tires set at 26 psi.

Boost was set to be proportional as I was only bringing in about 5 psi in first and second and ramping to 8.8 psi just before the shift into third. This was due to traction issues with the RSA's which was hurting the 60 ft times also.

With traction, it would be in the 12.3 - 12.5 range which is not to bad for a lowly 5.7 with just a bolt on power adder. You have to keep in mind, that the 5.7 has taller rear end gearing than the 6.1 which makes it more difficult to get in this range on a 5.7.

I am aware others with 5.7's have gone into the 12's without forced induction, but they have serious powertrain modifications to get there (heads, cams, headers, hi flow cats/exhaust, stall converters, pcm flashes, tranny flashes, some with nitrous, weight reduction, race fuel, etc.). This was with one out of the box bolt on that the owner can do over a weekend.

It is capable of far more boost than I am running, one of the R&D units in Florida input a bogus number in his boost control and went to 16psi on his 6.1 engine. No he did not pop the motor and it is not forged. But his AFR's and EGT's are under control plus the water/methanol spray increases with increasing boost which is probably why he didn't pop the top as he didn't get any detonation.

Mr MoPar
 

·
Registered
Joined
·
7,082 Posts
So...how much HP do you have with the turbo? Cost?
 
1 - 20 of 21 Posts
Top