As the title implies, this is only my experience on my car. I'm sure depending on what mods are on a given car, you'll get different results. This is on a 2003.5 G35 5AT coupe.

I bought the Crawford headers over a year ago, but finally got the time to get everything installed. They were Jethot coated before install. I had them installed at Street Image in Baldwin Park. It took them two days, good thing I didn't try the install myself.



Just a pic before install.

The "baseline" dyno is from July 2005 at Church Automotive. As most of you know, it's a dynapack, the absolute numbers are higher than a dynojet. But I'm comparing differences in power here, not absolute numbers. But I still expect someone to post that the numbers must be off, because it's higher than what they're used to seeing on a dynojet. I've seen stock non-revup 6MT 350z/g35s get about 255 on this dyno. Revup gets about 268-270, again ON THIS DYNO. Please don't try and compare this to a different dyno system, you'll get nowhere.

The mods from July 2005 are: popcharger, intake tube from Grubbs, ported throttle body, Crawford V5 plenum, a 1/4" spacer (yes, both, but it doesn't help more than just either a plenum OR spacer), japtrix B pipe, fuji Y-pipe, and the entire intake tract was port matched and polished from the venturi ring of the popcharger down to the intake on the heads.

This was some of the polish work:


The only mod since that time was the Crawford headers. I'm still running the stock ECU. It's the same dyno again. Obviously weather conditions are different, and I'm not running the exact same tank of gas (I can't make a full tank last 1.5 years). But I still ran 76 gas.


I don't have the data file yet, so I had to go off the printout. I like to plot averages vs. averages. I can tell you that the highest horsepower from July 2005 was 271.2@ 6422 RPM. Today it's 278.5@6416. But the mid range is an entirely different story.



Again, YMMV = your mileage may vary.

 

great numbers

 

Ouch! You lost low and midrange power only to gain a little power above 5800rpms. That's not good, man. Your car is now slower with the headers.

 

yeah man, i agree.... you should unistall that crap lol

 

EK,

Take off that 1/4" spacer.
Plus, when's the last time you had new plugs?

I just swapped out my plugs for some NGK Iridiums and she pulls like a beast again.

Let me know,
-DRU

 

Those are some serious "spagetti" headers !!!! Makes you wonder if they flow any better than stock.....

 

Yeah, I had Crawfords installed and although I hadn't done a dyno, I swear I'm a little slower.

 

weird, crawfords are considered the best headers for the 350z/g35

I was going to get them myself but chose Strup because with Jet hot the crawfords would be like $1400.

Also why didnt you do a dyno? After spending that much on headers..why not?

 

Crawfords are the best, so I hear, but with all of the "breathing" mods on NA engines, I'm convinced that you'll get no more than 10-15 hp. Don't get me wrong, I like the mods (setting myself up for SC soon), but I think these mods suit best "collectively" for FI, headers esp SC because of fitment. I think I got to a point of diminishing return with all of the current mods I have, feels like some torque is lost, believe me, I hate to admit it. Again, just my opinion.

 

With those mods, you should install UTEC in your car and get it tuned, then you'll really see/get the numbers you're looking for...

 

When I had my Stillen headers installed, I saw NO gain. In fact, it might have even gotten slower! lol

But after getting a reflash done... I love my car again!

 

what did Shawn say?

 

Hmm looks like you lost power from the beginning until you hit 5.8K RPM.

You lost about 10 whp at 5K RPM and started to gain and make more power from 5.8K to 6.4K and that was 8 whp at the top peak. It's not a good mod to me. Need ECU reflash maybe?

T

 

awesome! i still have crawford headers with otherwise stock exhaust (sans coupe middy), and still feel very nice low-end torque and high-end power improvement.

 

I'm running very lean with these mods now, and that's probably an understatement. I'm pretty sure that I'll need a good tune to maximize everything at this point. I just don't have $600+ right now for it at the moment. But I am done with engine mods, so a good tune is the most logical last step.

Meechin, I'm still running stock plugs. Shawn didn't add much, but he did find the results interesting.