Well, the Nismo S-tune exhaust sounds great, but nothing to write home about in terms of gains. Picked up a nice bump down low, but other gains throughout the rest of the rev range were very minimal at best.

I think this pretty much confirms that the best bang-for-the buck gains are to be had with just the test pipes...

http://www.the370z.com/members/jordo...n-w-tp-cbe.jpg

http://www.the370z.com/members/jordo...ed-camparo.jpg



However, check out the gains going from just K&N filters to full exhuast (minus headers), and going bone stock to the three bolt on's!

http://www.the370z.com/members/jordo...n-w-tp-cbe.jpg

http://www.the370z.com/members/jordo...k-n-tp-cbe.jpg



Very, very curious to see what the headers do... if the major bottlenecks are the cats, then I'm not overly optimisitic at the moment, but we'll see...

Also still have the pod filters. Probably won't be able to make use of the OEM airboxes as I'd hoped, but will have plenty of heat shielding so should work nicely. Probalby install and dyno them either later this week or next week.

Hmm... one more. This is of another run with the test pipes vs TP + CBE (both with K&N) and the gains look more even throughout hte rev range... consistent bump of about 3-5 to the tires.

http://www.the370z.com/members/jordo...-w-tp-cbe2.jpg

Doesn't really change my conclusions, but just thought it was interesting that this one showed improvement throughout the powerband.

Great job on doing all the dyno comparisons. I really want to see how my car does on a dynojet.

Thanks :tiphat:

Do you know off hand if there are any independent before and after dynos that show gains of CBE after a test pipe?

I'm starting to think that whatever the first exhaust mod done is, that ends up being the the one that picks up 10 -15 whp (with test pipes being the least expensive for that gain) and everything else just adds another 3-7 here and there.

I can't believe that the stillen or FI exhausts are all that different in design. There's only so many ways to massage a N/A motor with exhaust tubing :icon14:

However, this does leave me wondering further about seeing the difference between X, H, and Y pipes.

I'd say the two major improvements in the Nismo S-tune design are the better flowing Y and the straighter flowing tail pipes out the single mufler.

Has anyone switched between any of these and done comparison dynos?

I have to redyno mine soon eventually and post it here the result.

Cool.

Will be experimenting with another set of K&N filters and will be going tomorrow if they can get me on the dyno to test.

Yah, might give them a call first. Is that your custom intake you are talking about?

I hope to get good numbers this time

Sort of. OEM intake tubes and MAFS tube (cut from airbox) attached to two larger K&N filters (RX-4870 Amazon.com: K&N RX-4870 Universal X-Stream Clamp-on: Automotive: Reviews, Prices & more ). Black metal canister-like heat shielding. Either will work or won't -- I'll take pics if I keep it on.

I think my last attempt failed because the filters were too small and keeping the factory airboxes on created too much restriction -- nice idea, but just didn't work.

Whether or not it picks up any power, I'll be putting on the HPS intake tubes soon and testing those as well.

EDIT: Just tried them out -- test drive felt hesitant so I'm going to wait until after the intake tubes get here to experiment one last time while I'm on the dyno -- I have no idea why I'm not having any luck with this -- this isn't rocket science :icon14:

Got the HPS intake tubes on... not too bad an install (thanks in part to a buddy of mine who lended a hand).

Didn't even need to take the strut bar off -- but what a HUGE PITA getting the factory airboxes in and out now... I may not bother experimenting with filters again just because of the hassle involved in the swap :icon14:

Will dyno tomorrow. If I gain a few whp, I'll be happy, if not, I'll probably sell these off...

Finally dynoed with the HPS tubes and also a final experiment with K&N filters.

I only have a few comments:

1. The HPS tubes appear to do NOTHING.

EDIT: After further evaualtion of the dynos, old and new, I would say these are worthwhile in conjunction with K&N panel filters. Alone, not sure, but with high flow filters, reasonable bang for the buck, but a slight PITA to install.

Carefully reviewing the dynos, it looks like I intermittently lost or gained 2-3 whp at various points -- perhaps a little touch up with a tune will help.

However, if with tuning the overall gain will be less than 5 whp, I'm just going to sell these off -- worthless IMO.

2. No idea why the cone filters flow so poorly -- possibly all due to heat soak? They were shielded, but maybe not sufficiently?

No idea, but for now I would say the factory airboxes plus K&N panel filters is definitely the way to go.

Moreover, I would add that I've seen dynos where the much acclaimed Stillen intakes only make about 6-8 whp -- well below what they advertise, and the same gain you can get from just the K&N panel filters, which are like 1/4 the price...

http://www.the370z.com/members/jordo...ne-filters.jpg


Oh... and just to amuse myself... here's my "bragging rights" dyno. I'm at 300+ whp with std correction apparently... wheee.... :rolleyes:

http://www.the370z.com/members/jordo...ights-dyno.jpg

Of course, N/A, I go by SAE correction (tends to overcorrect for FI, BTW), so this is fairly empty boasting...

One other thought: I'd say that N/A the Z is probably maxed out around 295-310 (figure closer to the higher end with lighter pulleys and LTH's). With similar mods, anything less than that is probably an overly conservative estimate and anything over 310 is probably a happy dyno.

I see no clear evidence of differences in drivetrain loss from MT to AT either -- in fact, with comparable mods, mine seems to puts down as much or even a bit more than the 6 speeds have on PP's dyno -- go figure.

That's all for now... :hello:

jordo, just did 3 pulls at proven power the other day. I have top speed exhaust and custom short rams and peaked at 275whp and 229 torque. Better than what I expexted, especially for an exhaust that uses the stock y-pipe (getting that changed out soon) and heat soaked short rams.

Anyways, im with you. Full bolt ons and we are talking maybe 290-305/310 whp NA. Our cars dont like to dyno very high. After the Y-pipe im prob done with mods for speed

Hey man, YGPM.

You may want to ditch the short rams -- I have no idea exactly why, but they don't seem to perfom as well as the OEM airboxes with a high flow panel filter.

Also, yes, I suspect that the greatest gains in an exhaust come from swapping out the OEM Y-pipe (still not clear on whether improved Y, H or X yeilds better gains).

I would see about a HFC or test pipes too -- I will have a set of TP's for sale very soon if you are interested.

Nissan 370Z Z34 G37 VQ37 08-10 Exhaust Y-Pipe, Y Pipe - eBay (item 230498398242 end time Dec-09-10 12:15:10 PST)

since i already have the exhaust, you think this should work ok.

and you really think i should go back to stock air boxes?

The Y-pipe will probably net you another 3-5 on the average throughout the rev range -- I'd say 6-8 max. Price seems reasonable.

As to the SRI's, unless you did a baseline with them off to confirm they made power over OEM, yeah I do. I think you'll make more power with the stock airboxes plus K&N high flow panel filters.

If it wouldn't be a huge PITA to test, I would at least try it out.

Also, next time you go, you might want to do a second set of runs -- the ECU takes a full pulls to adjust itself, and I always see the gains "magically" appear on the second set of runs.

they charge 30 for 3 runs. do you know what they charge for the hour. and would you be interested in meeting up and maybe splitting the hour