FG mkii header question - feels sluggish?

[JayTay03]

Evening all,

 

I’ve fitted some Pacemaker 4495s with an eBay high flow cat to my FG mkii ute, when I purchased the car recently it had an Xforce cat back fitted to the stock cat pipe, with stock headers.

 

I know that the 4495s are typically better at providing greater gains in the upper rev range, however I really do feel that in this case the low down torque has suffered as compared to the stock manifold.

 

Is this an unusual experience? There seems to be some conflicting information around, as a lot of what I have read suggests the 4495 should make more torque and power across the entire rev range when compared to stock manifold and cat. I’m considering getting a set of 4490s, as id rather not feel I have to constantly thrash the tits off the car to make power.

 

For reference, car has growler intake and underdrive pulleys fitted, no tune. ZF 6 speed.

 

Any help or advice based on others’ experiences would be appreciated.

Edited 04/03/21 11:13 AM by JayTay03

[k31th]

 

yep, if you shift the power band a little into the higher revs, this usually comes at a cost to the lower revs.

 

Try a high-flow cat as well, it might help to even it out a bit... but if you just want the reasonable sound and similar to stock torque curve, the 4490's are a good idea.

 

You should just get a tune to see if it can compensate for the 4495's and the minor low-down grunt loss and also to make use of the growler and under-drive (get some injectors and a cat while you're at it)

[JayTay03]

Thanks for the reply and the welcome mate, I’ve got a high flow cat installed, as I mentioned, it’s one of the fairly common eBay high flow cats (extra bung for post cat o2 sensor.

 

I do understand there being a clear trade off in region of greatest efficiency based on pipe diameter and collector design etc. but it does seem to me at the moment that there is a noticeable pillaging of torque down low and that suggestions a high flow cat and 4495s will make more power everywhere than stock may not be entirely accurate.

Just took the car for a quick squirt and logged 0-100 in 6.5 on damp roads (inside speed limit, of course), so I suppose that’s not too bad for a Ute without a tune. In sports mode it did actually feel much better/quicker to respond and work with what appears to be reduced low rpm torque, I haven’t really used it to date as I didn’t think it would make much of a difference.

 

Would be nice to see a dyno sheet for the same car same day etc. only change being the 4490/4495.

 

Looks like I need to bite the bullet and get an X4!

[k31th]

oh, my bad, read it wrong haha you talked about a cat-back after mentioning you got the headers and cat... helps if I'm paying proper attention  

 

You'd be stoked to be doing 6.5 0-100 in an N/A... sounds like it's tuned, haha

 

Just marketing from pacemaker that the headers will increase power somewhere but not take away power from somewhere else, that's all.

 

I do remember somebody doing a back-to-back of 4490 vs 4495's but I can't remember if it was even on this forum or on AFF.

 

You don't need an X4 anymore, you can get a tune via hptuners or PCMTEC which goes straight onto your PCM without needing a box so can work out far cheaper to get tuned properly, especially as the N/A's don't need a ton of fiddling to get them in the right area with a tune in comparison to the turbo variants.

[JayTay03]

Yeah, definitely happy when I saw the numbers, was through the OBD port, so fairly comfortable with accuracy. Will keep digging to see if I can find the post, sounds like one of those all time stickies in the NA forum.

 

Thanks for the tune recommendations,  will definitely look into the other options, appreciate you sharing your knowledge mate.

[k31th]

yeah; I couldn't find it in a cursory search of this forum, so I'd suggest looking over on AFF

 

plenty of people here talking about 4495's or 4490's, but nobody with a direct comparison dyno chart that I could find, which is what I was thinking of.