I am new to this forum, and the world of eurocars and how they make horsepower, but Iam not new to American cars and motorcycles and how we make horsepower. Ihave built a number of Harleys from the ground up, a couple of American cars and spent 2 years with a semi pro NHRA Top Alcohol Funny car team, so Ido have some knowledge.
I am doing tons of research on buying a "fun car" and the Crossfire really has my eye in a big way. This is going to be a "project car" from the minute it rolls into my driveway and I want safety, reliability and performance in that order.

Before the oldtimers here tell me to "search", let me say I have. This is a massive database going back years, and the amount of information here is massive, but being a forum, it's not always easy to locate and it comes in pieces. Some info in a hundred forums and another piece in another hundred. I am seriously impressed with what's here, but for a neophyte, it's difficult to sort thru.

I have some performance questions about the NA XF and want to focus specifically on that. I fully understand the SRT and what it offers, but what it offers comes at a price of lacking certain abilities I find attractive. Please refrain from the "but the SRT has this or the SRTdoes this" comments.

With a NA XF, I know that the engine, as it comes stock, has the ability to generate one hell of a lot more horsepower that it comes with. Mercedes has a long history of racing and that technology has created an entire aftermarket industry just to make horsepower, and that includes engines not using superchargers. With the difference in cost between a NA and an SRT, Im thinking of taking that money and building a XF engine to significantly increase the horsepower. I have read the turbocharger thread and the problems encountered. I've searched online and don't find any other sources that have gone down this road and offer a system for the XF, which is a shame.

With a NA engine, and using bolt on parts, to improve intake airflow, engine management software, ignition, a complete exhaust system, what are the reasonable horespower increases that could be seen? I've have read the threads where this engine is dissed because it doesn't have the "forged rods" and other parts in the SRT, but Iknow enough about engines that it would be possible to easily increase the horsepower in this engine by at least a factor of 2 without even beginning to worry about the ability of the internals to take that kind of power. The question is how much horsepower can be made with this NA engine and how to get there, and in what order?

I may well buy an SRT, in fact Iam leaning heavily that direction, but before I do I want to look long and hard at going down this path. I plan on finding exactly the right car and keeping it, making every winter downtime to make changes. My goal is one very fast, responsive car that holds the road like a slot car, and is not something you see very often.

I want to tap the wealth of knowledge that exists here, but like every internet forum out there, on every subject imaginable, there are those who actually have the knowledge, and those that talk like they do. I really want to talk to those ofyou who are not only enthusiasts, but gearheads.

 

Well, here is the sum of my knowledge on the NA engine, listing the mods I have done :
1. Needswings CAI ( single, dual is overkill on an NA )
2. 74mm throttle body
3. Eurotune engine tune.
I think ( no dyno ) I am somewhere around 260 HP with these mods.
From EVERYTHING I have read, exhaust mods return very little on the $ spent, although I did install an OBC Racing catback ( Borla Chinese rip-off ).
The only thing I might still do is a brake upgrade with SRT6 front rotors and calipers.

 

There are some dyno charts on here showing NA hp and as I recall they do not show too much above 200 hp at the wheels.
A factor of two increase would mean 400 hp and the SRT engine can just make it. Figures are from my head so I might be out a few hundred hp.
I am not answering the first post so any inference that I am is purely conjectural.

 

Onehundred80

I didn't mean to imply that this engine can reach 400hp as a NA, just that the internals such as the cast rods should be able to accept such horsepower.

 

I think a few have thrown NOX at it, but not too much info on the forum about that.
You can also do research in the MB forums on any model with 320 in it to see what they have done.

 

Onehundred80

I didn't mean to imply that this engine can reach 400hp as a NA, just that the internals such as the cast rods should be able to accept such horsepower.

 

I'm not sure what kind of performance you want to attain, but I know of only one NA car to have broke into the 13's, and that was with NOS.

 

How much power it makes all depends on how much money you are willing to spend, but with this being a mercedes engine, the aftermarket support is not there.
And depends on what you want to do with your car, fun car that gets good milage, or a weekender to romp on.

 

And if you want to do a v8 swap, the nsg370 is good for 279 or 289 lbs torque, so no bigger than a mb 5.0, a 5.5 if you know somewhere that can beef up the 6 speed trans from a jeep wrangler, then the engine swap is tuning to make run.
And there has been other conversion like a full hemi swap and a LS swap, full kit new ls computer and harness and all the goodies to have the ls run in a XFire will cost the same as just a tune to make a 5.0 mb engine run, but also have to change out gauge cluster, wiring, ignition etc.
As I said depends on budget and what you want to do with it.

 

The OP has not been around in just over ten months.

 

op ???????

 

OP = Original Poster.

 

What I thought, didn't know November 2017 to January 2018 was 10 months apart.

Huh,
Need to learn atleast 1 thing a day or that day is wasted, guess that makes me good for today

 

I appreciate the responses but I decided to go in a different direction and purchased a 2007 Mercedes SL55 AMG with a supercharged v8. I drove an SRT and while it was a fun car, the SL55 is just a better all around car for us. The luxury is pure MB and the torque is mind boggling. Enjoyed reading about the Crossfires and learned an awful lot, bot pro and con.

 

Sorry, I do not know how I came up with that.
Guess I am an idiot, or I answered another post in the wrong thread.

 

Bet you got a laugh
I bet I have more brain fats