anyone intalled NHP full exhaust??? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

2K3_Boxster_S · 07-03-2009, 10:42 PM

Dynoed Today on a Dynapack, so there would be no questions about variables. there are no tension straps, no rollers, wheel spin, deflection etc.....

Dynapack info:
http://autospeed.com/cms/title_The-Dynapack-Dyno/A_0930/article.html

Video Results of my stock 2003 Boxster S:

http://s80.photobucket.com/player.swf?file=http://vid80.photobucket.com/albums/j179/ryancausey/boxterfinal1.flv&fs=1&os=1&ap=1

Looking at back on Dyno in 2 weeks Full NHP installed.

23109VC · 07-03-2009, 11:51 PM

can't wait for the results!!!! thanks for doing this - i'm sure I"m not the only one anxious to see the results. I'd also like to hear how it sounds.

aside from dyno numbers - I'd be interested in your subjective impressions as to how it seems to drive/perform - seat of the pants observations.

Topless · 07-04-2009, 12:48 AM

Yikes! Looks like a huge hole in performance at 4300 rpm. Low numbers for a Box S also. Bad MAF??? Spark plugs?? I have seen a lot of Boxster dyno results. Something looks very wrong here.

stateofidleness · 07-04-2009, 03:01 AM

i know nothing about dyno's and such, but 186hp on an "S"?
I thought my MY00 stock 2.7 was rated at 210hp... is yours low, or is mine high?

seems like the S should be putting out a lot more, even a stock one.

edevlin · 07-04-2009, 04:33 AM

Interesting stuff, keep the dyno sheets comming....

Ed

2K3_Boxster_S · 07-04-2009, 09:03 AM

Quote:

Originally Posted by stateofidleness

i know nothing about dyno's and such, but 186hp on an "S"?
I thought my MY00 stock 2.7 was rated at 210hp... is yours low, or is mine high?

seems like the S should be putting out a lot more, even a stock one.

its horsepower to the wheels, not what the engine can make. Those numbers put my car around 250 hp.

2K3_Boxster_S · 07-04-2009, 08:57 AM

Quote:

Originally Posted by Topless

Yikes! Looks like a huge hole in performance at 4300 rpm. Low numbers for a Box S also. Bad MAF??? Spark plugs?? I have seen a lot of Boxster dyno results. Something looks very wrong here.

nothing wrong with the car it runs great.

2K3_Boxster_S · 07-04-2009, 09:05 AM

Quote:

Originally Posted by Topless

Yikes! Looks like a huge hole in performance at 4300 rpm. Low numbers for a Box S also. Bad MAF??? Spark plugs?? I have seen a lot of Boxster dyno results. Something looks very wrong here.

go put your car on a dynapack and lets see whats going on.

Topless · 07-04-2009, 09:38 AM

Here is another dynapack run with a bone stock Boxster S for comparison.
http://i4.photobucket.com/albums/y144/bisimoto/DeSnorked986S.jpg

Do you see what I mean about your cars hole at 4300 rpm(down to 140 ft lbs)? Peak performance is much lower on your run also. I am not here to burn you down. I just figure if you want to get a good baseline run before tuning your car it should look similar to other stock Box S runs to be valid. Looking at your numbers I suspect a fouled/contaminated MAF.

Topless · 07-04-2009, 10:09 AM

Here is another run with a well tuned 98 Boxster spec car. The motor is a stock 2.5L crate motor that was recently installed. This run was under ideal conditions on a cool morning at sea level. These are the best results I have seen with a stock 2.5L. Note the big fat torque curve at 4500 rpm. This car sings.

http://www.boxsterspec.com/uploads/monthly_01_2009/post-49-1232326727_thumb.jpg

2K3_Boxster_S · 07-04-2009, 09:45 PM

Quote:

Originally Posted by Topless

Here is another dynapack run with a bone stock Boxster S for comparison.
http://i4.photobucket.com/albums/y144/bisimoto/DeSnorked986S.jpg

Do you see what I mean about your cars hole at 4300 rpm(down to 140 ft lbs)? Peak performance is much lower on your run also. I am not here to burn you down. I just figure if you want to get a good baseline run before tuning your car it should look similar to other stock Box S runs to be valid. Looking at your numbers I suspect a fouled/contaminated MAF.

hmm. yes I see what you are saying. your dyno sheet drops at almost the same exact point. not nearly as drastically though 10Lbs i think. I'm also looking at a difference in the Rpms and Mph, don't think that matters though. If its a plug or MAF you can not tell by driving the car. Plus shouldn't you get a CEL if it was the MAF?

Jake Raby · 07-05-2009, 07:48 AM

Quote:

Originally Posted by 2K3_Boxster_S

hmm. yes I see what you are saying. your dyno sheet drops at almost the same exact point. not nearly as drastically though 10Lbs i think. I'm also looking at a difference in the Rpms and Mph, don't think that matters though. If its a plug or MAF you can not tell by driving the car. Plus shouldn't you get a CEL if it was the MAF?

There are lots of issues that can reduce output without throwing a CEL.. some of these are MAF issues, others are fuel pressure or fuel injector related and even issues with catalytic converters.

Or a low power engine may have an impending mechanical issue... I haven't ever seen a healthy Boxster S engine that didn't make at minimum 205HP at the wheels.. That engine was very tired with near 30,000 track miles on it.

Jake Raby · 07-09-2009, 07:36 PM

Cool.. I consider the AFR data more important during this evaluation than the HP output... But then again, I average HP numbers before I even look at peak numbers, because peak is so very worthless unless you drive around at above 5,252 RPM ALL THE TIME.

2K3_Boxster_S · 07-10-2009, 10:18 PM

Quote:

Originally Posted by Jake Raby

Cool.. I consider the AFR data more important during this evaluation than the HP output... But then again, I average HP numbers before I even look at peak numbers, because peak is so very worthless unless you drive around at above 5,252 RPM ALL THE TIME.

Porsche has had my car since Monday (AC service) I get home from work today (Friday) "hey your car's ready". Not sure if I can get this done before 7/19. If not it's going to be another month. (out of town again, for work). I could just bolt up the exhaust, but I want to do this the right way. and from what every one has said about the Dyno sheets, something doesn't look right. which is why I insist on re-dynoing it.

This could take awhile. oh well,

2K3_Boxster_S · 07-19-2009, 06:14 PM

Ok, It didn't get done. I'm out of town again. return Aug. 15. It will be dyno'ed upon return on a roller dyno with AFR readings. Then NHP exhaust will then be installed and re-dynoed on same dyno. Sorry for the wait. But I feel an accurate baseline is needed so we can know what effects of the NHP setup is going to give us. Please hang in there. THANKS

here is a quote from the person who dynoed right after my on the same dyno:

"Yeah I thought yours seemed a little low even for a stocker.. but as they said that dyno is stingy. Dunno, mine dyno'd 90hp and 50ftlb down from last time.. but .. different style dyno, different conditions"

So yeah I'm gonna find a different dyno.

later

2K3_Boxster_S · 08-16-2009, 01:51 AM

Following has been installed:

5w-40 Castrol Syn

6 new Interpulse Plugs

NHP Full Exhaust installed

I can not tell specifically from driving on HP gains. I can say the back end broke loose like it never has before.

To me the sound is fine. if it gets to lound in the cabin all you have to do is go up a gear and it instantly quiets down to nothing. this is acceptable for me. but I also don't us the radio much.

try to dyno next weekend.

Old Beru Plugs

cnavarro · 08-16-2009, 10:12 AM

Long term update - probably a solid 8,000 mi on a full NHP exhaust on our '99 with sport cats. Cats started throwing a CEL about 2,000 mi and had to add o2 sensor extensions to fix the CEL. After the last track weekend, there's a rattle somewhere in the tip or mufflers, looks like their heat shield is coming loose.